CLINICAL APPROPRIATENESS GUIDELINES ADVANCED IMAGING Apprpriate Use Criteria: EFFECTIVE JANUARY 1, 2019 Prprietary 8600 West Bryn Mawr Avenue Suth Twer Suite 800 Chicag, IL 60631 www.aimspecialtyhealth.cm Apprpriate.Safe.Affrdable 2017 2019 AIM Specialty Health 2057-0119
Table f Cntents Descriptin and Applicatin f the Guidelines... 4 Administrative Guidelines... 5 Ordering f Multiple Studies... 5 Simultaneus Ordering f Multiple Studies... 5 Repeated Imaging... 5 Pre-Test Requirements... 6 Histry... 6... 7 General Infrmatin/Overview... 7 Scpe... 7 Technlgy Cnsideratins... 7 Definitins... 8 Clinical Indicatins... 9 Cngenital and Develpmental Cnditins... 9 Ataxia, cngenital r hereditary... 9 Develpmental delay (Pediatric nly)... 9 Cngenital cerebral anmalies... 10 Infectin... 10 Infectin... 10 Inflammatry Cnditins... 11 Multiple sclersis and ther white matter diseases... 11 Inflammatry cnditins, unspecified... 11 Trauma... 11 Trauma... 11 Tumr r Neplasm... 12 Acustic neurma (Adult nly)... 12 Pituitary adenma (Adult nly)... 13 Tumr nt therwise specified... 13 Miscellaneus Cnditins... 14 Bell s palsy (peripheral facial nerve palsy)... 14 Cerebrvascular accident r transient ischemic attack... 14 Dementia (Adult nly)... 15 Hrner s syndrme... 16 Hydrcephalus/ventricular assessment... 16 Mental status change and encephalpathy... 17 Mvement disrders (Adult nly)... 17 Neurcutaneus disrders... 18 Pseudtumr cerebri (Pediatric nly)... 18 Seizure disrder... 18 Seizure, refractry... 19 Cpyright 2019. AIM Specialty Health. All Rights Reserved. 2
Trigeminal neuralgia and persistent idipathic facial pain (Adult nly)... 20 Periperative/Periprcedural Imaging... 20 Lumbar puncture risk assessment... 20 Signs and Symptms... 20 Dizziness r vertig... 21 Headache... 21 Hearing lss... 25 Papilledema... 25 Syncpe... 26 Tinnitus (Adult nly)... 26 Visual disturbance... 26 Cdes... 27 References... 27 Histry... 34 Cpyright 2019. AIM Specialty Health. All Rights Reserved. 3
Descriptin and Applicatin f the Guidelines The AIM Clinical Apprpriateness Guidelines (hereinafter the AIM Clinical Apprpriateness Guidelines r the Guidelines ) are designed t assist prviders in making the mst apprpriate treatment decisin fr a specific clinical cnditin fr an individual. As used by AIM, the Guidelines establish bjective and evidence-based criteria fr medical necessity determinatins where pssible. In the prcess, multiple functins are accmplished: T establish criteria fr when services are medically necessary T assist the practitiner as an educatinal tl T encurage standardizatin f medical practice patterns T curtail the perfrmance f inapprpriate and/r duplicate services T advcate fr patient safety cncerns T enhance the quality f health care T prmte the mst efficient and cst-effective use f services The AIM guideline develpment prcess cmplies with applicable accreditatin standards, including the requirement that the Guidelines be develped with invlvement frm apprpriate prviders with current clinical expertise relevant t the Guidelines under review and be based n the mst up-t-date clinical principles and best practices. Relevant citatins are included in the References sectin attached t each Guideline. AIM reviews all f its Guidelines at least annually. AIM makes its Guidelines publicly available n its website twenty-fur hurs a day, seven days a week. Cpies f the AIM Clinical Apprpriateness Guidelines are als available upn ral r written request. Althugh the Guidelines are publicly-available, AIM cnsiders the Guidelines t be imprtant, prprietary infrmatin f AIM, which cannt be sld, assigned, leased, licensed, reprduced r distributed withut the written cnsent f AIM. AIM applies bjective and evidence-based criteria, and takes individual circumstances and the lcal delivery system int accunt when determining the medical apprpriateness f health care services. The AIM Guidelines are just guidelines fr the prvisin f specialty health services. These criteria are designed t guide bth prviders and reviewers t the mst apprpriate services based n a patient s unique circumstances. In all cases, clinical judgment cnsistent with the standards f gd medical practice shuld be used when applying the Guidelines. Guideline determinatins are made based n the infrmatin prvided at the time f the request. It is expected that medical necessity decisins may change as new infrmatin is prvided r based n unique aspects f the patient s cnditin. The treating clinician has final authrity and respnsibility fr treatment decisins regarding the care f the patient and fr justifying and demnstrating the existence f medical necessity fr the requested service. The Guidelines are nt a substitute fr the experience and judgment f a physician r ther health care prfessinals. Any clinician seeking t apply r cnsult the Guidelines is expected t use independent medical judgment in the cntext f individual clinical circumstances t determine any patient s care r treatment. The Guidelines d nt address cverage, benefit r ther plan specific issues. If requested by a health plan, AIM will review requests based n health plan medical plicy/guidelines in lieu f the AIM Guidelines. The Guidelines may als be used by the health plan r by AIM fr purpses f prvider educatin, r t review the medical necessity f services by any prvider wh has been ntified f the need fr medical necessity review, due t billing practices r claims that are nt cnsistent with ther prviders in terms f frequency r sme ther manner. Cpyright 2019. AIM Specialty Health. All Rights Reserved. 4
Administrative Guidelines Ordering f Multiple Studies Requests fr multiple imaging studies t evaluate a suspected r identified cnditin and requests fr repeated imaging f the same anatmic area are subject t additinal review t avid unnecessary r inapprpriate imaging. Simultaneus Ordering f Multiple Studies In many situatins, rdering multiple imaging studies at the same time is nt clinically apprpriate because: Current literature and/r standards f medical practice supprt that ne f the requested imaging studies is mre apprpriate in the clinical situatin presented; r One f the imaging studies requested is mre likely t imprve patient utcmes based n current literature and/r standards f medical practice; r Apprpriateness f additinal imaging is dependent n the results f the lead study. When multiple imaging studies are rdered, the request will ften require a peer-t-peer cnversatin t understand the individual circumstances that supprt the medically necessity f perfrming all imaging studies simultaneusly. Examples f multiple imaging studies that may require a peer-t-peer cnversatin include: CT brain and CT sinus fr headache MRI brain and MRA brain fr headache MRI cervical spine and MRI shulder fr pain indicatins MRI lumbar spine and MRI hip fr pain indicatins MRI r CT f multiple spine levels fr pain r radicular indicatins MRI ft and MRI ankle fr pain indicatins Bilateral exams, particularly cmparisn studies There are certain clinical scenaris where simultaneus rdering f multiple imaging studies is cnsistent with current literature and/r standards f medical practice. These include: Onclgic imaging Cnsideratins include the type f malignancy and the pint alng the care cntinuum at which imaging is requested Cnditins which span multiple anatmic regins Examples include certain gastrintestinal indicatins r cngenital spinal anmalies Repeated Imaging In general, repeated imaging f the same anatmic area shuld be limited t evaluatin fllwing an interventin, r when there is a change in clinical status such that imaging is required t determine next steps in management. At times, repeated imaging dne with different techniques r cntrast regimens may be necessary t clarify a finding seen n the riginal study. Repeated imaging f the same anatmic area (with same r similar technlgy) may be subject t additinal review in the fllwing scenaris: Repeated imaging at the same facility due t mtin artifact r ther technical issues Repeated imaging requested at a different facility due t prvider preference r quality cncerns Cpyright 2019. AIM Specialty Health. All Rights Reserved. 5
Repeated imaging f the same anatmic area (MRI r CT) based n persistent symptms with n clinical change, treatment, r interventin since the previus study Repeated imaging f the same anatmical area by different prviders fr the same member ver a shrt perid f time Pre-Test Requirements Critical t any finding f clinical apprpriateness under the guidelines fr specific imaging exams is a determinatin that the fllwing are true with respect t the imaging request: A clinical evaluatin has been perfrmed prir t the imaging request (which shuld include a cmplete histry and physical exam and review f results frm relevant labratry studies, prir imaging and supplementary testing) t identify suspected r established diseases r cnditins. Fr suspected diseases r cnditins: Based n the clinical evaluatin, there is a reasnable likelihd f disease prir t imaging; and Current literature and standards f medical practice supprt that the requested imaging study is the mst apprpriate methd f narrwing the differential diagnsis generated thrugh the clinical evaluatin and can be reasnably expected t lead t a change in management f the patient; and The imaging requested is reasnably expected t imprve patient utcmes based n current literature and standards f medical practice. Fr established diseases r cnditins: Advanced imaging is needed t determine whether the extent r nature f the disease r cnditin has changed; and Current literature and standards f medical practice supprt that the requested imaging study is the mst apprpriate methd f determining this and can be reasnably expected t lead t a change in management f the patient; and The imaging requested is reasnably expected t imprve patient utcmes based n current literature and standards f medical practice. If these elements are nt established with respect t a given request, the determinatin f apprpriateness will mst likely require a peer-t-peer cnversatin t understand the individual and unique facts that wuld supersede the pre-test requirements set frth abve. During the peert-peer cnversatin, factrs such as patient acuity and setting f service may als be taken int accunt. Histry Status Date Actin Reviewed and revised 07/26/2016 Independent Multispecialty Physician Panel review and revisin Created 03/30/2005 Original effective date Cpyright 2019. AIM Specialty Health. All Rights Reserved. 6
General Infrmatin/Overview Scpe These guidelines address advanced imaging f the brain in bth adult and pediatric ppulatins. Fr interpretatin f the Guidelines, and where nt therwise nted, adult refers t persns age 19 and lder, and pediatric refers t persns age 18 and yunger. Where separate indicatins exist, they are specified as Adult r Pediatric. Where nt specified, indicatins and prerequisite infrmatin apply t persns f all ages. See the Cding sectin fr a list f mdalities included in these guidelines. Technlgy Cnsideratins Cmputed tmgraphy (CT) is preferred in the fllwing situatins: initial evaluatin f cranicerebral trauma; evaluatin f acute intracranial hemrrhage (parenchymal, subarachnid, subdural, epidural); evaluatin f calcified intracranial lesins; sseus assessment f the calvarium, skull base, and maxillfacial bnes, including detectin f calvarial and facial bne structures; and imaging f midline structures and ventricular system. CT is utilized less frequently in neurimaging due t inferir reslutin when cmpared t MRI. CT als has a tendency t result in beam-hardening artifact adjacent t the petrus bne, which may limit visualizatin in prtins f the psterir fssa and brainstem. Standard anatmic cverage f head CT is frm the base f the skull t its vertex, cvering the entire calvarium and intracranial cntents. Cverage may vary depending n the specific clinical indicatin. Disadvantages f CT include expsure t inizing radiatin and risks assciated with infusin f idinated cntrast media, including allergic reactins r renal cmprmise. Magnetic resnance imaging (MRI) is preferable t CT in mst clinical scenaris. It is the study f chice fr visualizatin f brain parenchyma and white matter tracts. It is als preferred fr imaging f the psterir fssa and brainstem structures. Standard anatmic cverage f head MRI is frm the base f the skull t the vertex, cvering the entire calvarium and intracranial cntents, including the internal auditry canals. Cverage may vary depending n the specific clinical indicatin. The presence f implantable devices such as pacemakers r defibrillatrs, a ptential need fr sedatin in pediatric patients, and claustrphbia are the main limitatins f MRI. Infusin f gadlinium may als cnfer an unacceptable risk in persns with advanced renal disease. Diffusin-weighted imaging (DWI) is a specific MRI sequence that gathers infrmatin n the mvements f water mlecules in the brain. DWI is mst cmmnly used t diagnse pathlgies in which water mlecules demnstrate less ability t mve thrugh the histlgic structure f the brain. Cmmn examples include acute ischemic strke, abscess, and certain tumrs. DWI can als be used t image structure f white matter tracts by a prcess called diffusin tensr imaging (DTI), which uses the data frm the scan t make calculatins. DTI may als be useful in neursurgical planning. Functinal MRI (fmri) is primarily utilized fr mapping primary brain activities related t mtr, sensry, and language functins. Studies have demnstrated that fmri is cmparable t the intracartid sdium ambarbital prcedure (Wada test) and direct electrical stimulatin fr language lcalizatin. fmri is nninvasive, des nt require inizing radiatin, and has a shrter time requirement fr imaging and pstprcedural recvery. Psitrn emissin tmgraphy (PET) prvides functinal infrmatin abut brain activity by mapping the relative cncentratins f certain raditracers within the parenchyma. PET brain imaging is primarily used t evaluate bld flw, metablic changes, and neurtransmitter dynamics, and is frequently perfrmed in cnjunctin with CT fr anatmic lcalizatin. PET/CT can be used t evaluate many types f dementia and memry disrders, and it can als be used t lcalize epileptic seizures r stage brain tumrs. Cpyright 2019. AIM Specialty Health. All Rights Reserved. 7
Magnetic resnance spectrscpy (MRS), usually perfrmed with standard MRI, prvides a bichemical prfile f metablic cnstituents in tissues. Alteratins in specific metablites such as chline and creatine are assciated with certain disease states; this infrmatin can be used as an adjunct in cases where standard MRI fails t distinguish between diseased and healthy tissue. In neurimaging, MRS is useful fr differentiating between tumr, necrtic tissue, and certain types f infectius lesins. Definitins Phases f the care cntinuum are bradly defined as fllws: Screening testing in the absence f signs r symptms f disease Diagnsis testing based n a reasnable suspicin f a particular cnditin r disrder, usually due t the presence f signs r symptms Management testing t direct therapy f an established cnditin, which may include preperative r pstperative imaging, r imaging perfrmed t evaluate the respnse t nnsurgical interventin Surveillance peridic assessment fllwing cmpletin f therapy, r fr mnitring knwn disease that is stable r asymptmatic Statistical terminlgy 1 Cnfidence interval (CI) range f values which is likely t cntain the cited statistic. Fr example, 92% sensitivity (95% CI, 89%-95%) means that, while the sensitivity was calculated at 92% n the current study, there is a 95% chance that, if a study were t be repeated, the sensitivity n the repeat study wuld be in the range f 89%-95%. Diagnstic accuracy ability f a test t discriminate between the target cnditin and health. Diagnstic accuracy is quantified using sensitivity and specificity, predictive values, and likelihd ratis. Hazard rati dds that an individual in the grup with the higher hazard reaches the utcme first. Hazard rati is analgus t dds rati and is reprted mst cmmnly in time-t-event analysis r survival analysis. A hazard rati f 1 means that the hazard rates f the 2 grups are equivalent. A hazard rati f greater than 1 r less than 1 means that there are differences in the hazard rates between the 2 grups. Likelihd rati rati f an expected test result (psitive r negative) in patients with the disease t an expected test result (psitive r negative) in patients withut the disease. Psitive likelihd ratis, especially thse greater than 10, help rule in a disease (i.e., they substantially raise the pst-test prbability f the disease, and hence make it very likely and the test very useful in identifying the disease). Negative likelihd ratis, especially thse less than 0.1, help rule ut a disease (i.e., they substantially decrease the pst-test prbability f disease, and hence make it very unlikely and the test very useful in excluding the disease). Odds rati dds that an utcme will ccur given a particular expsure, cmpared t the dds f the utcme ccurring in the absence f that expsure. An dds rati f 1 means that the expsure des nt affect the dds f the utcme. An dds rati greater than 1 means that the expsure is assciated with higher dds f the utcme. An dds rati less than 1 means that the expsure is assciated with lwer dds f the utcme. Predictive value likelihd that a given test result crrelates with the presence r absence f disease. Psitive predictive value is defined as the number f true psitives divided by the number f test psitives. Negative predictive value is defined as the number f true negatives divided by the number f test negative patients. Predictive value is dependent n the prevalence f the cnditin. Cpyright 2019. AIM Specialty Health. All Rights Reserved. 8
Pretest prbability prbability that a given patient has a disease prir t testing. May be divided int very lw (less than 5%), lw (less than 20%), mderate (20%-75%), and high (greater than 75%) althugh these numbers may vary by cnditin. Relative risk prbability f an utcme when an expsure is present relative t the prbability f the utcme ccurring when the expsure is absent. Relative risk is analgus t dds rati; hwever, relative risk is calculated by using percentages instead f dds. A relative risk f 1 means that there is n difference in risk between the 2 grups. A relative risk f greater than 1 means that the utcme is mre likely t happen in the expsed grup cmpared t the cntrl grup. A relative risk less than 1 means that the utcme is less likely t happen in the expsed grup cmpared t the cntrl grup. Sensitivity cnditinal prbability that the test is psitive, given that the patient has the disease. Defined as the true psitive rate (number f true psitives divided by the number f patients with disease). Excellent r high sensitivity is usually greater than 90%. Specificity cnditinal prbability that the test is negative, given that the patient des nt have the disease. Defined as the true negative rate (number f true negatives divided by the number f patients withut the disease). Excellent r high specificity is usually greater than 90%. Clinical Indicatins The fllwing sectin includes indicatins fr which advanced imaging f the brain is cnsidered medically necessary, alng with prerequisite infrmatin and supprting evidence where available. Indicatins, diagnses, r imaging mdalities nt specifically addressed are cnsidered nt medically necessary. It is recgnized that imaging ften detects abnrmalities unrelated t the cnditin being evaluated. Such findings must be cnsidered within the cntext f the clinical situatin when determining whether additinal imaging is required. Cngenital and Develpmental Cnditins Ataxia, cngenital r hereditary Includes ataxia-telangiectasia, fragile X syndrme, and cngenital anmalies f the psterir fssa Advanced imaging is cnsidered medically necessary fr diagnsis and management when the results f imaging will impact treatment decisins. - CT r MRI brain Develpmental delay (Pediatric nly) Advanced imaging is cnsidered medically necessary fr evaluatin f EITHER f the fllwing cnditins: Cerebral palsy Significant delay r lss f milestnes in ANY TWO (2) f the fllwing dmains: Activities f daily living Cgnitin Mtr skills (grss/fine) Scial/persnal Cpyright 2019. AIM Specialty Health. All Rights Reserved. 9
Speech/language - CT r MRI brain Cngenital cerebral anmalies Includes Chiari malfrmatin, cranisynstsis, macrcephaly, and micrcephaly Advanced imaging is cnsidered medically necessary fr diagnsis and management when the results f imaging will impact treatment decisins. - CT r MRI brain - Ultrasund required as the initial study t evaluate macrcephaly in patients under 5 mnths f age Ratinale Cngenital anmalies f the central nervus system can be classified 2 int disrders f drsal/ventral inductin such as myelmeningcele, hlprsencephaly, Dandy-Walker variant, r cranisynstsis, disrders f neural prliferatin such as micrcephaly and megalencephaly, disrders f neurnal migratin such as schizencephaly and crtical hetertpias, and disrders f myelinatin such as adrenleukdystrphy and Canavan disease. There are characteristic imaging patterns fr each f these cngenital abnrmalities, making imaging an imprtant diagnstic test. Repeat imaging and surveillance imaging are indicated nly if neurlgical cmplicatins f these cnditins are suspected such as hydrcephalus. The American Academy f Neurlgy recmmends neurimaging in the diagnstic evaluatin f a child with glbal develpmental delay, 3 which is defined as a delay in 2 r mre develpmental dmains grss/fine mtr cntrl, speech/language, cgnitin, scial/persnal, and activities f daily living that affect children under the age f 5 years. 4 While histry and physical exam are sufficient t establish the diagnsis in up t a third f cases, 4 structural abnrmalities n neurimaging are seen in 14% f unselected patients and in 41% f patients with suggestive physical exam findings such as macrcephaly r fcal neurlgical deficits. 3 Cerebral palsy is the mst cmmn physical disability in childhd and refers t a syndrme f vluntary mvement r psture that manifests befre age 2. 5 MRI has a high sensitivity (86%-89%) fr the cnditin 6 with 70%-90% f patients having identifiable structural abnrmalities. Neurimaging in general and MRI in particular are recmmended by the American Academy f Neurlgy t help establish the diagnsis. 7 MRI is the preferred imaging mdality fr evaluatin f cngenital and develpmental abnrmalities f the brain because it is mre sensitive than CT fr the detectin f mrphlgical abnrmalities f the brain parenchyma and because it des nt require inizing radiatin. Abnrmalities n MRS have been assciated with develpmental delay, but have nt cnsistently been shw t imprve diagnstic yield f change management as either an add-n r a replacement test t MRI. 4 CT may be preferred t better characterize cngenital abnrmalities that primary invlve the calvarium, such as cranisynstsis. 8 Ultrasund is als sensitive and shuld be cnsidered in clinical practices with expertise in the technique. 9 Ultrasund is an accurate and reliable initial mdality fr evaluating macrcephaly in nenates, and it can identify a small percentage (2%) f patients wh require neursurgical interventin. 10 Macrcephaly withut fcal neurlgical deficits has a very lw (3.5%) incidence f cngenital abnrmalities, and add-n MRI r CT detectin has a very lw (0%) impact n management. 11 Infectin Infectin Advanced imaging is cnsidered medically necessary fr diagnsis and management when the results f imaging will impact treatment decisins. - CT r MRI brain Cpyright 2019. AIM Specialty Health. All Rights Reserved. 10
Inflammatry Cnditins Multiple sclersis and ther white matter diseases Advanced imaging is cnsidered medically necessary fr diagnsis and management when results f imaging will impact treatment decisins. - MRI brain - CT brain (when MRI cntraindicated) Inflammatry cnditins, unspecified Advanced imaging is cnsidered medically necessary fr diagnsis and management when the results f imaging will impact treatment decisins. - CT r MRI brain Trauma Trauma Des nt apply t patients with bleeding diatheses r intracranial shunts in whm advanced imaging may be perfrmed when the results will impact management decisins. ADULT Advanced imaging is cnsidered medically necessary in the initial evaluatin f head trauma when a mechanism f injury has been identified and ANY f the fllwing features is present: Age 65 years r lder Retrgrade amnesia At least 2 episdes f emesis Evidence f pen, depressed, r basilar skull fracture Fcal neurlgic findings Glasgw cma scale less than 15 r altered mental status High-risk mechanism f injury Seizure PEDIATRIC - CT brain fr initial evaluatin - MRI brain (fllwing CT, when required t direct management r infrm prgnsis) Advanced imaging is cnsidered medically necessary in the initial evaluatin f head trauma when EITHER f the fllwing is present: Nn-accidental injury Trauma assciated with ANY f the fllwing features: Altered mental status Cpyright 2019. AIM Specialty Health. All Rights Reserved. 11
Change in behavir Vmiting Lss f cnsciusness Histry f high-risk mtr vehicle accident r ther mechanism f injury Scalp hematma when yunger than age 2 years Evidence f basilar skull fracture - CT r MRI brain Ratinale AIM adult trauma guidelines fllw well established clinical predictin rules fr this indicatin. In particular, AIM guidelines fllw the Canadian Head CT rules (CCHR) develped and externally validated n thusands f Nrth American level 1 trauma center patients, a ppulatin at highest risk fr clinically significant head trauma. 12 While bth the New Orleans Criteria and the Canadian Head CT rules have excellent sensitivity (100% CI: 96%-100%) fr clinically imprtant brain injury, the Canadian Head CT rules achieve this sensitivity with substantially greater specificity (range 37%-50.7% vs 3%-12.7%), 13-15 resulting in imprved verall diagnstic accuracy. Of nte, patients with new fcal neurlgical deficits and seizures are usually candidates fr neurimaging regardless f whether they are pst-traumatic, and altered mental status (Glasgw cma scale < 15) is als addressed in separate AIM guidelines and as such is included here as criteria even thugh it is nt a part f the CCHR clinical predictin rule (which als applies t patients with a Glasgw cma scale f 13 t 15). Patients with a bleeding diasthesis r intracranial shunts were excluded frm the develpment f the CCHR, s imaging can be perfrmed whenever clinically significant trauma is suspected. Guidelines fr pediatric head trauma fllw a similar apprach, adpting the Pediatric Emergency Care Applied Research Netwrk (PECARN) rules fr the detectin f clinically significant brain injury. The PECARN rules were develped (33,785) and validated (8627) in multiple Nrth American emergency departments 16 with fr example subsequent separate multicenter gegraphy validatins. 17 Sensitivity f PECARN in this ppulatin is 98.8% (CI 89%- 99.6%) and the rule did nt miss neursurgical head trauma in any pediatric patients. 16 While PECARN is less specific (53% vs 91%) cmpared t clinical gestalt, the rule is substantially mre sensitive (~100% vs 60%), 18 althugh the greater specificity f clinical gestalt is questined by ther studies. 19 Cmpared t ther clinical predictin rules fr pediatric head trauma (including CATCH and CHALICE), PECARN has a higher sensitivity (100% vs 91% and 84%, althugh cnfidence intervals verlap) and has undergne mre extensive external validatin. 19 High-risk mechanisms as defined in the AIM adptin f PECARN include mtr vehicle cllisin with patient ejectin r rllver, death f anther passenger, pedestrian r bicyclist withut helmet struck by a mtrized vehicle, high-impact head trauma, falls frm mre than 3 feet. CT is the preferred imaging mdality fr acute head trauma because it is mre sensitive fr intracranial hemrrhage and fracture, mre readily available than MRI, and takes less time t perfrm. 20 MRI is an add-n advanced imaging test in select cases f acute head trauma, especially in situatins where abnrmalities n the neurlgical exam are unexplained by head CT r are wrsening r prgressive. 21 MRI is mre sensitive fr the evaluatin f diffuse axnal injury (DAI) and micrhemrrhage, which may explain this discrepancy. The presence f DAI has been assciated with a mdest (dds rati = 3) risk f unfavrable utcme, 22 althugh there is currently n effective treatment. 23 Other experimental advanced imaging techniques such as DTI, fmri, and MRS are prmising, but have nt been cnsistently shwn t change management r imprve patient level prgnsis as add-n tests and are nt in widespread clinical use at this time. 24 Tumr r Neplasm Acustic neurma (Adult nly) Als see indicatin fr hearing lss. Advanced imaging is cnsidered medically necessary fr management f knwn acustic neurma in ANY f the fllwing scenaris: Symptms suggestive f recurrence r prgressin Fllwing cnservative treatment r incmplete resectin at 6, 18, 30, and 42 mnths Cpyright 2019. AIM Specialty Health. All Rights Reserved. 12
Pst resectin baseline imaging and fllw up at 12 mnths after surgery - CT r MRI brain Pituitary adenma (Adult nly) Advanced imaging is cnsidered medically necessary in EITHER f the fllwing scenaris: Diagnsis f suspected pituitary adenma when supprted by symptms and labratry findings Management (including periperative evaluatin) f knwn adenma - CT r MRI brain Ratinale Pituitary adenmas can be bradly classified int clinically functining (hrmne-secreting, typically presenting with abnrmal lab values and systematic signs/symptms with r withut neurlgic nes) and clinically nnfunctining (typically presenting with neurlgical signs/symptms related t reginal extensin and mass effect). Fr suspected functinal adenmas, the Endcrine Sciety recmmends MRI in patients with bichemically prven acrmegaly t evaluate fr a functining pituitary adenma as well as t visualize tumr size and reginal extensin; CT is suggested if MRI is cntraindicated r unavailable. 25 In additin, the American Cllege f Radilgy identifies MRI with and withut cntrast as usually apprpriate fr patients with hyperthyridism, hyppituitarism, Cushing s syndrme, hyperprlactinemia, diabetes insipitus, and preccius puberty. 26 The Cngress f Neurlgical Surgens recmmends MRI as the advanced imaging mdality f chice in the preperative diagnsis f nnfunctinal pituitary adenmas with ptential supplementatin by CT, but ntes insufficient evidence t supprt MR spectrscpy, perfusin, and PET/CT fr this indicatin. 27 Pituitary applexy is a special case f pituitary adenma that results frm acute hemrrhage r infarct f the pituitary and that presents with severe headache (up t 97%), visual deficits, and/r phthalmplegia, and requires emergent MRI. 26,28 Applexy is cmmnly assciated with pituitary adenmas (up t 90% f the time). 28 The Cngress f Neurlgical Surgens als recmmends fllw-up MRI fr patients with knwn nnfunctinal pituitary adenmas after surgery r radiatin therapy, but ntes that the evidence is insufficient t make recmmendatins abut the frequency f imaging with the exceptin f surveillance. Additinally, subttal resectins shuld be fllwed mre clsely than grss ttal nes, and surveillance shuld begin at least 3 mnths after surgical interventin. 29 Fr patients with functinal adenmas that are causing acrmegaly, the Endcrine Sciety recmmends MRI at least 12 weeks after surgery r serial MRI in patients receiving pegvismant medical therapy, 25 while the American Cllege f Radilgy recmmends MRI with and withut cntrast fr further characterizatin f the pstperative sella. 26 A pituitary incidentalma is a previusly unsuspected pituitary lesin that is discvered n an imaging study perfrmed fr an unrelated reasn. 30 The majrity f pituitary incidentalmas are adenmas and the cnditin is prevalent ccurring in 10% f autpsy specimens. 30 Fr incidentalmas identified n CT, the Endcrine Sciety recmmends a dedicated MRI t further characterize. Fr adenmas that are nt treated, the Endcrine Sciety recmmends peridic surveillance at 6 mnths and 1 year with suggested tapering f subsequent fllw up frequency fr stable findings. 30 Tumr nt therwise specified See Onclgic Imaging guidelines fr management f an established tumr. Advanced imaging is cnsidered medically necessary fr evaluatin f suspected tumr when supprted by the clinical evaluatin. - CT r MRI brain - MRS t differentiate tumr frm ther diagnses such as abscess r anther infectius/inflammatry lesin when a structural brain lesin has been identified Cpyright 2019. AIM Specialty Health. All Rights Reserved. 13
Miscellaneus Cnditins Bell s palsy (peripheral facial nerve palsy) Advanced imaging is cnsidered medically necessary in EITHER f the fllwing scenaris: Additinal neurlgic findings suggestive f intracranial pathlgy (atypical presentatin) Symptms persisting beynd 6 weeks in the absence f additinal neurlgic findings - CT r MRI brain Ratinale Bell s palsy is an idipathic disruptin f facial nerve functin that typically manifests as facial nerve paralysis and ipsilateral facial muscle weakness. It is mst cmmnly self-limiting, reslving in 60%-90% f patients. 31,32 While Bell s palsy is a diagnsis f exclusin, it is rare fr intracranial lesins t cause islated facial nerve palsy. 31 Neurimaging fr Bell s palsy is generally reserved fr patients with additinal neurlgical signs and/r symptms r in cases that fail t respnd in a self-limited fashin. When imaging is apprpriate, MRI is recmmended ver CT, 33 as MRI can visualize bth the cisternal and intracanalicular curse f the 7th cranial nerve. Specialty sciety and practice based guidelines recmmend against rutine imaging fr Bell s palsy. The American Academy f Otlarynglgy Guideline recmmends that clinicians nt rutinely perfrm diagnstic imaging fr patients with new-nset Bell's palsy. 34 The American Cllege f Radilgy states "In general, Bell's palsy patients need nt be imaged unless the symptms are atypical r persist fr > 2 mnths." 33 Cerebrvascular accident r transient ischemic attack See Vascular Imaging guidelines. Advanced imaging is cnsidered medically necessary fr diagnsis and management when the results f imaging will impact treatment decisins. - CT brain is preferred fr evaluatin f acute hemrrhagic cerebrvascular accident - MRI brain is preferred fr subacute r chrnic hemrrhage and ischemia Ratinale Cerebrvascular accident (CVA), als knwn as strke, is the fifth leading cause f mrtality and ne f the leading causes f mrbidity in the United States. The American Strke Assciatin predicts that nearly 800,000 peple will suffer a strke in 2018, f which mre than 120,000 will die. 35 A strke is a cnditin caused by insufficient bld flw t the brain. The 2 main types f strke are ischemic and hemrrhagic. Ischemic strkes are caused by an cclusin f an arterial bld vessel and cmprise almst 90% f all strkes. 36 These can develp lcally (thrmbtic strke) r riginate frm ther parts f the bdy (emblic strke). Hemrrhagic strkes, n the ther hand, are caused by bleeding, either intraparenchymal r subarachnid. In bth frms, patients may acutely present with partial r full paralysis f muscles, visin and speech disturbances, r change in level f cnsciusness. 35 Transient ischemic attack (TIA) has been traditinally defined as the sudden lss f neurlgic functin that recvers cmpletely within 24 hurs. TIA cnfers an increased risk f strke 11.3% (95% CI 7.5% t 16.6%) within the subsequent 90 days 37 and may be related t mimics such as migraine, epilepsy, functinal disrders, and neplasm in up t 50% f cases. Althugh the diagnstic yield f neurimaging fr an alternative etilgy is lw (< 5%), 37 imaging with CT r MRI is imprtant t exclude a rare but treatable structural cause like a tumr r subdural hemtma. As clinical predictin rules such as the ABCD2 scre miss up t 20% f pst-tia strkes 38 and as MRI (with diffusinweighted imaging) may identify strkes in up t 34% f patients, 37 neurimaging may be helpful in selecting patients fr subsequent treatment, which may include mre aggressive medical management such as dual antiplatelet therapy and high-dse statin therapy. 39 Vascular imaging may be indicated t identify critical extracranial stensis, as these patients benefit frm cartid endarterectmy r stenting 40 and echcardigraphy may be used t diagnse atrial fibrillatin. 41 Patients presenting with acute strke wh are candidates fr tissue plasmingen activatr (tpa) r mechanical thrmbectmy benefit frm immediate advanced brain and head and neck vascular imaging (CT/CTA r MR/MRA), as advanced imaging was a majr selectin criterin fr the 5 recent randmized cntrl trials MR CLEAN, ESCAPE, REVASCAT, SWIFT PRIME, and EXTEND IA) that established the net benefit f thrmbectmy in selected patients. 42 With the recent publicatin f the DAWN and DEFUSE-3 trials, patients with acute strke and wake-up strke presenting with 6-24 hurs may be candidates fr thrmbectmy when MR r CT perfusin shws a mismatch between at risk tissue and infarct cre. 43,44 Cpyright 2019. AIM Specialty Health. All Rights Reserved. 14
In patients presenting with strke wh are nt candidates fr tpa r mechanical thrmbectmy, strke evaluatin may invlve neurimaging t establish the diagnsis and vascular imaging t identify critical extracranial stensis r as 35, 45 therwise needed t infrm management. Regarding mdality selectin fr vascular imaging, ultrasund has cmparable sensitivity (> 95%) t advanced nninvasive vascular imaging (CTA/MRA) fr anterir circulatin TIA r CVA. Ultrasund als has gd negative predictive value fr critical stensis, and is ften used as an initial exam with advanced vascular imaging as a prblem slving tl r fr preperative planning. 46,47,48 Fr psterir circulatin infarcts, advanced vascular imaging is mre sensitive than ultrasund and is usually the primary mdality f chice when indicated t direct management. 49 Dementia (Adult nly) Advanced imaging is cnsidered medically necessary in EITHER f the fllwing scenaris: Initial evaluatin t exclude a secndary cause f symptms Evaluatin f rapidly prgressive symptms - MRI brain - CT brain (when MRI cntraindicated) A ne-time FDG-PET scan fr differentiating between frnttempral dementia and Alzheimer s disease is cnsidered medically necessary prvided that ALL f the fllwing cnditins are met: A recent diagnsis f frnttempral dementia r Alzheimer s disease made by a physician experienced in the evaluatin f dementia Dcumentatin f cgnitive decline f at least 6 mnths duratin A cmprehensive clinical evaluatin, including ALL f the fllwing: Histry and physical examinatin, including an assessment f activities f daily living frm a well-acquainted infrmant ther than the patient Cgnitive scales r neurpsychlgical testing Labratry testing t evaluate fr metablic causes f cgnitive impairment Structural imaging f the brain (CT r MRI) t identify a structural cause fr cgnitive impairment The evaluatin has nt clearly identified a specific neurdegenerative disease r ther cause fr the clinical symptms Results f the PET scan will help clarify the diagnsis in rder t guide future treatment A brain SPECT has nt been btained fr the same indicatin Nte: Dcumentatin f this evaluatin, including results f all testing, and a current list f medicatins are required. Ratinale Dementia is an umbrella term fr a grup f symptms assciated with a decline in memry and ther cgnitive functins. Neurdegenerative disrders, f which Alzheimer s disease is the mst cmmn, are ften respnsible fr dementia. 50,51 Tw kinds f advanced imaging, structural and functinal, are available fr further characterizatin f dementia. Structural imaging includes MRI and CT, and evaluates fr masses and fr mrphlgic changes in the brain parenchyma. Functinal imaging includes PET/CT and SPECT, and evaluates fr metablic changes in the brain parenchyma. Structural imaging Advanced structural imaging is recmmended by multiple specialty sciety guidelines t exclude a treatable cause fr dementia, such as neplasm, hydrcephalus, r subdural hematma. 52,53,54,55,56,57,58 The ratinale fr this recmmendatin is that n clinical predictin rule has sufficient accuracy t exclude treatable causes f dementia, 57 and apprpriately 2.2% f patients presenting with dementia will have a treatable cause (such as subdural hematma, hydrcephalus, r neplasm) that advanced imaging can identify. 56 Cpyright 2019. AIM Specialty Health. All Rights Reserved. 15
MRI is the preferred advanced imaging mdality fr initial evaluatin. It is mre sensitive than CT fr the evaluatin f treatable causes and ffers the secndary benefit f imprved cntrast between grey and white matter; hence MRI prvides better assessment f patterns f parenchymal atrphy that characterize specific frms f dementia (fr instance, supranuclear palsy, frnttempral dementia, and primary prgressive aphasia). 59,52,53 Advanced structural imaging (MRI preferred) is indicated t exclude new treatable causes in a previusly imaged patient with dementia, particularly when there is rapid (e.g., ver 1 t 2 mnths) unexplained decline in cgnitin r functin. 60,61 Advanced imaging shuld be undertaken in the assessment f a persn with cgnitive impairment and unsuspected cerebrvascular disease, if it wuld change the clinical management. 60 Functinal imaging The American Cllege f Radilgy indicates that advanced imaging mdalities such as FDG-PET are nt rutinely used in cmmunity r general practices fr the diagnsis r differentiatin f frms f dementia. 59 Hwever, FDG-PET may be useful in select circumstances as a prblem-slving technique t direct management. The Eurpean Federatin f Neurlgical Scieties recmmends its use in thse cases where the diagnsis remains in dubt after clinical and structural MRI wrkup and in particular clinical settings. 52 Gauthier et al. 62 indicate that FDG-PET may be useful in frming a differential diagnsis fr a patient with dementia wh has undergne the recmmended baseline clinical and structural brain imaging evaluatin and wh has been evaluated by a dementia specialist, but whse underlying pathlgical prcess is still unclear, preventing adequate clinical management. Evidentiary basis fr the abve recmmendatins includes several diagnstic accuracy studies f FDG-PET using clinical assessment as the reference standard. These studies fund a diagnstic accuracy f 93% fr differentiating Alzheimer s disease subjects frm healthy subjects, with sensitivity f 96% and specificity f 90%. Hwever, use f a clinical reference standard instead f histpathlgy limits internal validity. A multicenter analysis in 138 patients with histpathlgical diagnses reprted that FDG-PET crrectly identified the presence r absence f Alzheimer s disease in 88% f the cases, with a sensitivity f 94% and a specificity f 73%. 52 MRI variants including fmri and MRS are nt recmmended by high quality evidence based guidelines fr rutine use in dementia imaging. These mdalities d nt have a rle in the evaluatin r mnitring f dementia, 52 and are intended nly fr specialized clinical and research settings. 60 Future studies with large number f participants and lnger perid f fllw up are needed t allw firm cnclusins n the value f fmri as an add-n test t MRI, fr instance, in early detectin f dementia and n predicting is. 62 Hrner s syndrme Advanced imaging is cnsidered medically necessary fr diagnsis and management when the results f imaging will impact management. - MRI brain - CT brain (when MRI cntraindicated) Ratinale Hrner s syndrme is cnditin that results frm a disruptin f the sympathetic nervus supply t the eye and is characterized by the triad f misis, ptsis, and anhidrsis. 63 Evaluatin f Hrner s syndrme begins with a cmplete neurlgical and phthalmlgical examinatin, which may reveal an etilgy fr the cnditin such as surgical trauma. Additinal neurlgical features such as additinal cranial nerve deficits may lcalize the pathlgy t the brain, in which case a sequential diagnstic testing strategy starting with brain MRI may be pssible. In nnlcalized cases, the entire curse f the culsympathetic pathway may need t be visualized, including an MRI f the brain and an MRI, CT, r MRA/CTA f the neck if there is cncern fr cartid 64, 65 dissectin as a cause. The yield f diagnstic imaging in islated Hrner s syndrme is apprximately 15%-20% and the mst cmmn etilgies identified by neurimaging are cartid artery dissectins and cavernus sinus masses. Children can als develp Hrner s syndrme and neurimaging typically MRI f the head, neck, and smetimes chest identifies a cause in up t 33% f patients. 66 Unlike with adults, neplasms such as neurblastma and Ewing sarcma are the mst cmmn etilgies fr Hrner s syndrme identified by neurimaging. Hydrcephalus/ventricular assessment Advanced imaging is cnsidered medically necessary in EITHER f the fllwing scenaris: Evaluatin f signs r symptms suggestive f increased intracranial pressure r hydrcephalus Management f established hydrcephalus and ventricular shunts Cpyright 2019. AIM Specialty Health. All Rights Reserved. 16
- CT r MRI brain - Ultrasund required fr initial evaluatin in patients under 5 mnths f age Ratinale Hydrcephalus is dilatin f the ventricular system resulting frm bstructin f cerebrspinal fluid flw r excess prductin. 67 Hydrcephalus can be further classified based n physilgy and time f nset. Physilgically, hydrcephalus can be cmmunicating (n macrscpic bstructin t cerebrspinal fluid (CSF) flw but inadequate resrptin in the subarachnid space) r bstructive (where a mass lesin blcks CSF flw within the ventricular system). Temprally, hydrcephalus can be classified as cngenital (present at birth) r acquired (ccurring after birth). 68 Neurimaging can be used t diagnse hydrcephalus based n clinical signs and symptms f increased intracranial pressure and t fllw changes in ventricular size after treatment r when recurrence is suspected. Cngenital hydrcephalus is mst cmmnly caused by aqueductal stensis, which can be visualized n MRI. Other etilgies such as neural tube defects, Chiari malfrmatin, and Dandy-Walker Syndrme are disrders f brain parenchyma frmatin ptimally visualized by MRI. While the evidence is insufficient t recmmend a specific threshld fr ventricular size change t evaluate treatment respnse, 69 changes in ventricular size measured by either CT r MRI can be helpful t assess fr shunt malfunctin. 70 Nrmal pressure hydrcephalus (NPH) is a type f acquired hydrcephalus that typically ccurs in lder adults and is characterized by the triad f gait disturbance, urinary incntinence, and memry impairment. NPH is als characterized by the presence f nrmal CSF pressure n lumbar puncture (LP), neurimaging findings f enlarged cerebral ventricles, and imprvement after ventricular shunting. While neurimaging either by MRI r CT can suggest the diagnsis f NPH, there is incnsistent and insufficient evidence fr the prgnstic value f imaging findings such as periventricular fluid and aqueductal flw vids. 71 In nenates with pen fntanelles, cranial ultrasund allws reliable assessment f hydrcephalus and is the initial imaging mdality f chice, since it des nt require expsure f this high-risk ppulatin t inizing radiatin (unlike CT), r sedatin and/r prlnged immbility (unlike MRI). 72 Acquired hydrcephalus can als be secndary due t bstructing lesins such as intraventricular tumrs, intraventricular hemrrhage, r cllid cysts. Therefre, neurimaging plays a central rle in identifying an etilgy fr bstructin, with MRI being mre sensitive than CT in the majrity f cases. 67 Mental status change and encephalpathy Advanced imaging is cnsidered medically necessary fr initial evaluatin when dcumented by neurlgic exam and the results f imaging will impact management. - CT r MRI brain Mvement disrders (Adult nly) Advanced imaging is cnsidered medically necessary fr initial evaluatin f the fllwing mvement disrders, t exclude an underlying structural lesin: Hemifacial spasm Huntingtn s disease Multiple system atrphy Parkinsn s disease with atypical features Prgressive supranuclear palsy Secndary dystnia Other fcal r lateralizing mvement disrder, such as hemiballismus, athetsis, r chrea Nte: Imaging is generally nt indicated fr evaluatin f typical Parkinsn s disease, essential tremr, r primary dystnia. - CT r MRI brain Cpyright 2019. AIM Specialty Health. All Rights Reserved. 17
Ratinale Imaging has a limited rle in mst mvement disrder cnditins. The mst cmmn f these are essential tremr, with a prevalence f 5% f individuals ver the age f 65, and Parkinsn s disease, with a prevalence f 1% in this ppulatin. Structural MRI, as used in current clinical practice, des nt reveal significant abnrmalities in essential tremr. Diagnsis f essential tremr is based n clinical assessment f the phenmenlgical characteristics and its curse. 73 Parkinsn s disease is a clinical and pathlgical diagnsis, with MRI limited t atypical presentatins f the disrder. Patients shuld initially be referred t a specialist fr diagnsis. Rates f incrrect diagnsis fr specialists average ~7%, while thse fr nn-specialists run between 25%-47%. Typical presentatin: resting tremr, cgwheel rigidity, bradykinesia, with delayed nset f pstural instability. When clinical signs and symptms and respnse t medicatin are typical f Parkinsn s disease, neurimaging is nt required. 59 Atypical features f Parkinsn s disease 74 include the fllwing: falls at presentatin and early in the disease curse; pr respnse t levdpa; symmetry at nset; rapid prgressin; lack f tremr; dysautnmia (urinary urgency/incntinence and fecal incntinence, urinary retentin requiring catheterizatin, persistent erectile failure, r symptmatic rthstatic hyptensin). Imaging may be indicated in cases f atypical Parkinsn s disease t exclude treatable causes. Other mvement disrders such as multiple system atrphy have characteristic imaging features that may be used t crrbrate the diagnsis when clinically uncertain. 59,74,75 Dystnia is characterized by sustained muscle cntractins, frequently causing repetitive twisting mvements r abnrmal pstures. The diagnsis is clinical and specialist referral is recmmended. Features f primary dystnia include the fllwing: absence f assciated neurlgical signs r symptms ther than tremr; absence f additinal mtr abnrmalities (weakness, spasticity, etc.); early nset (< 21) starts in the limbs and may generalize; late nset ( 21) begins in the neck/arm/face and des nt generalize. Structural brain imaging is nt rutinely required when there is a cnfident diagnsis f primary dystnia in adults, but may be indicated t evaluate secndary frms f dystnia. 76 Neurcutaneus disrders Includes neurfibrmatsis, Sturge-Weber syndrme, tuberus sclersis, and vn Hippel-Lindau disease Advanced imaging is cnsidered medically necessary fr diagnsis and management (including periperative evaluatin) f central nervus system lesins assciated with a knwn neurcutaneus disrder. - CT r MRI brain Pseudtumr cerebri (Pediatric nly) Advanced imaging is cnsidered medically necessary fr diagnsis and management when the results f imaging will impact treatment decisins. - CT r MRI brain Seizure disrder ADULT Advanced imaging is cnsidered medically necessary in ANY f the fllwing scenaris: Initial evaluatin, t rule ut a structural brain lesin as a cause f seizure Evaluatin f seizures increasing in frequency r severity Prir t discntinuatin f anticnvulsant therapy in patients wh have nt been previusly imaged PEDIATRIC Advanced imaging is cnsidered medically necessary in ANY f the fllwing scenaris: Nenatal/infantile seizure (age 2 years r yunger) when EITHER f the fllwing is present: Cpyright 2019. AIM Specialty Health. All Rights Reserved. 18