Utility of radiologic imaging in the diagnosis and follow up of normal pressure hydrocephalus Poster No.: C-0312 Congress: ECR 2015 Type: Scientific Exhibit Authors: C. Rodríguez, D. Marquina, A. Mir Torres, C. Sebastián, C. Ospina, A. C. Vela, M. Marin Cardenas; Zaragoza/ES Keywords: DOI: Outcomes, Cerebrospinal fluid, Outcomes analysis, Diagnostic procedure, MR, CT, Neuroradiology brain 10.1594/ecr2015/C-0312 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. www.myesr.org Page 1 of 20
Aims and objectives To evaluate the utility of imaging features in the diagnosis of normal pressure hydrocephalus (NPH) and in predicting the outcome after ventriculoperitoneal shunt (VPS). To illustrate the radiological changes after surgery. To investigate whether there is a relationship between clinical outcome and onset time of symptoms. Methods and materials Introduction: Normal pressure hydrocephalus (NPH) is a treatable symptomatic complex, characterized by gait disorders, progressive dementia and urinary incontinence (Hakim- Adams triad). Even though the intracranial pressure in NPH has been considered to be normal, various studies have shown alterations which encompass a wide spectrum, from average normal pressures without fluctuations to high pressures with fluctuations. Etiology: With regard to the etiological mechanisms in NPH, there are idiopathic forms and forms secondary to other neurological processes (two-thirds of the cases), such as subarachnoid hemorrhage (the most frequent within this group), brain injuries, meningitis or intracranial surgery. The idiopathic forms of NPH generally appear in the 6th-7th decades of life, while the secondary ones appear at any age. Physiopathology: In normal conditions, during systole, the cerebral volume expands and a pressure wave is produced which compresses both the cortical veins and the lateral ventricles, which Page 2 of 20
secondarily leads to a descending flow of the cerebrospinal fluid (CSF) through the Sylvian aqueduct. On the contrary, during diastole, the decrease in the cerebral blood volume produces an ascending flow of CSF through the Sylvian aqueduct and enlarged ventricles. In NPH, due to a decrease in the distensibility of the cerebral parenchyma, the CSF tends to accumulate in the ventricular system, resulting in a much greater CSF in the aqueduct. Imaging findings: The preferred imaging modalities for the study of this entity are computed tomography (CT) and magnetic resonance imaging (MRI), whose main radiological findings are: 1. Disproportionately expanded ventricles (figure 1). 2. Rounded appearance of the frontal horns of the lateral ventricles (figure 1). 3. Ballooning of the 3rd ventricle (figure 1). 4. Increase of Evan s index (figure 2). 5. Expanded Sylvian fissures (figure 3). 6. Thinning of the corpus callosum, due to the pressure exerted on it by the dilated ventricles (figure 3). 7. Tight high-convexity subarachnoid spaces (figure 4) 8. Focal dilatation of the cerebral sulci (figure 4). 9. Periventricular hyperintensities related to chronic ischemia (figure 5). 10. Absence of signal in proton density weighted MRI due to an increase of the dynamics of CSF and the increased rate through narrow structures such as the Sylvian aqueduct (figure 6). Phase-Contrast Cine MR Imaging: Phase-Contrast Cine MR Imaging Technique with cardiac gating allow the study of the dynamic CSF flow measurements at the level of the acqueduct with an analysis that is both qualitative and quantitative, through the calculation of the velocity and the volume of systolic, diastolic and average flow, as well as the flow volume per cycle, called stroke volume (SV). The SV or volume of the CSF per beat is the flow volume during the diastole and during the systole measured in microlitres per beat. It is the average flow volume per cycle regardless of the direction (figure 7). In the year 1996, Bradley W. et al published an article affirming that the patients with a SV greater than 42 microlitres/beat were patients who were supposedly good responders to the implantation of VPS, while those presenting a stroke volume of less than 42 were Page 3 of 20
considered to be bad responders. Subsequently it was verified that the values of SV are modified throughout the evolution of the disease. Therefore, in the first months, there is a progressive increase in the values of this parameter, subsequently they reach a maximum value and finally there is a progressive decrease; thus, the question is posed of whether the time of evolution also affects the response to surgical treatment, as well as the values of the SV. Patients: Between January 2007 and February 2013, we examined 50 patients with suspected NPH. 21 patients were not candidates for VPS on the basis of comorbidity or age, 3 were on waiting list for surgery and the remaining 26 were treated with VPS. For the clinical and radiological evaluation in shunted patients, lumbar puncture, Katzman test, Evan s index, size of the Sylvian fissures, presence or absence of focal dilatation of the cerebral sulci, white-matter changes and SV were recorded. Onset time on symptoms until VPS and radiological changes after surgery were also recorded. Images for this section: Page 4 of 20
Fig. 1: Enlarged ventricles, rounded appearance of frontal horns and rounded appearance of frontal horns. Page 5 of 20
Fig. 2: Evans Index. Page 6 of 20
Fig. 3: Expanded Sylvian fissures and thinning of the corpus callosum. Page 7 of 20
Fig. 4: Tight high-convexity and focal dilatation of the cerebral sulci. Page 8 of 20
Fig. 5: White matter-hyperintensities. Page 9 of 20
Fig. 6: Hypointensity at the level of the aqueduct on proton density-weighted MRI. Page 10 of 20
Fig. 7: Stroke-Volume (SV). Page 11 of 20
Results The value of cine-pc in the study of NPH does not predict the response to the implantation of VPS, to the contrary of what was thought at first. There is no value of the SV above which patients will be good responders to surgery, as its value varies throughout the evolution of the disease and only reflects a state of hyperdinamia of the CSF. In our study, of the 26 patients operated on, 11 improved clinically, in all (5) or some symptom (6) (table 1). Of these 11 patients, 9 had been operated on in the first 12 months after the clinical diagnosis (table 2). With regard to the preoperative imaging study, 11 patients presented periventricular hyperintensities of absent or mild degree, of which 5 presented clinical improvement after surgery. Of the 15 patients with preoperative hyperintensities of moderate or generalized degree (table 3), 9 did not present clinical improvement after the shunt procedure (table 4). These differences were not statistically significant, due to the small number of patients included in the study. The imaging control studies after surgery showed reversal of the dilation of the Sylvian fissures in 2 patients, decrease of arachnoid spaces in 5 and recovery of the cerebral sulci in 7 (table 5 and figure 8). Among all patients with radiological improvement after VPS, 4 also experienced clinical improvement. We do not have long-term imaging controls, basically because many of the patients included in our study have been operated on recently or they have only been controlled by clinical evolution. Images for this section: Page 12 of 20
Table 1: Clinical improvement. Page 13 of 20
Table 2: Clinical improvement. Page 14 of 20
Table 3: Clinical improvement in absent-mild eriventricular hyperintensities group of patients. Page 15 of 20
Table 4: Clinical improvement in moderate-generalized periventricular hyperintensities group of patients. Page 16 of 20
Table 5: Radiological improvement. Page 17 of 20
Fig. 8: Radiological improvement. Page 18 of 20
Conclusion The presence of white-matter hyperintensities associated with ischemic degeneration in patients with NPH, and long time elapsed from onset of symptoms to VPS, were predictors of a poor outcome after shunt surgery. The fact that many patients were not candidate for surgery on the basis of comorbidity or age means an important limitation of the study sample. Personal information References 1. Adams RD, Fisher CM, Hakim S, Ojemann RG, Sweet WH: Symptomatic occult hydrocephalus with "normal" cerebrospinal-fluid pressure: a treatable syndrome. N Engl J Med 1965, 273:117-126. 2. Hakim S, Adams RD. The special clinical problem of symptomatic hydrocephalus with normal cerebrospinal fluid pressure. Observations on cerebrospinal fluid hydrodynamics. J Neurol Sci 1965;2:307-327. 3. Bradley WG Jr, Kortman KE, Burgoyne B. Flowing cerebrospinal fluid in normal pressure hydrocephalic states: appearance on MR images. Radiology 1986;159:611-16. 4. Bradley WG Jr, Whittemore AR, Kortman KE, et al. Marked cerebrospinal fluid void: indicator of successful shunt in patients with suspected normalpressure hydrocephalus. Radiology 1991;178:459-66. 5. Bradley WG Jr, Scalzo D, Queralt J, et al. Normal-pressure hydrocephalus: evaluation with cerebrospinal fluid flow measurements at MR imaging. Radiology 1996;198:523-29. 6. Bradley WG Jr. MR prediction of shunt response in NPH: CSF morphology versus physiology. AJNR Am J Neuroradiol 1998;19:1285-86. 7. Boon AJ, Tans JT, Delwel EJ, et al. Dutch Normal-Pressure Hydrocephalus Study: randomized comparison of low- and medium-pressure shunts. J Neurosurg 1998;88:490-95. 8. Marmarou A, Young HF, Aygok GA, Sawauchi S, Tsuji O, Yamamoto T, Dunbar J: Diagnosis and management of idiopathic normal-pressure hydrocephalus: a prospective study in 151 patients. J Neurosurg 2005, 102:987-97. 9. Bateman GA, Levi CR, Schofield P, et al. The pathophysiology of the aqueduct stroke volume in normal pressure hydrocephalus: can comorbidity with other forms of dementia be excluded? Neuroradiology 2005;47:741-48. Page 19 of 20
10. Kahlon B, Annertz M, Ståhlberg F, at al. Is aqueductal stroke volume, measured with cine phase-contrast magnetic resonance imaging scans, useful in predicting outcome of shunt surgery in suspected normal pressure hydrocephalus? Neurosurgery 2007;60:124-30. 11. Shprecher, D, Schwalb J, Kurlan R. Normal Pressure Hydrocephalus: Diagnosis and Treatment. Curr Neurol Neurosci Rep. 2008 September ; 8(5): 371-376. 12. Scollato A, Tenenbaum R, Bahl G, et al. Changes in aqueductal CSF stroke volume and progression of symptoms in patients with unshunted idiopathic normal pressure hydrocephalus. AJNR Am J Neuroradiol 2008;29:193-98. 13. Scollato A, Gallina P, Di Lorenzo N, et al. Changes in Aqueductal CSF Stroke Volume in Shunted Patients with Idiopathic Normal-Pressure Hydrocephalus. AJNR Am J Neuroradiol 2009; 30: 1580-86. 14. Hashimoto M, Ishikawa M, Mori E, Kuwana N. Diagnosis of idiopathic normal pressure hydrocephalus is supported by MRI-based scheme: a prospective cohort study. Cerebrospinal Fluid Research 2010;7:18. 15. Bargalló N, Auger C, Rovira A. Malformaciones congénitas en el adulto. Epilepsia. Hidrocefalia. del Cura JL, Pedraza S, Gayete A. Radiología Esencial. Primera Edición. Madrid: Editorial Médica Panamericana; 2009. 1227-1253. Page 20 of 20