kingstonegems.com Precious Stones: Gems of the urogenital system Nordic Forum 2017, Helsinki, Finland Ken F Linnau MD, MS Emergency Radiology

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1 kingstonegems.com Precious Stones: Gems of the urogenital system Nordic Forum 2017, Helsinki, Finland Ken F Linnau MD, MS Emergency Radiology

2 59 year old woman Intermittent right flank pain Pain radiates into the right groin Hematuria No abdominal tenderness on exam What does she have? Diagnosis and differential What needs to be done? Medical treatment or surgical intervention

3 Outline - Nephrolithiasis Rationale approach to imaging diagnosis CT KUB vs US Differential considerations Imaging technique Low dose scan Positioning Unusual urolithiasis Indinavir stone Staghorn calculi XGP Bladder stones Dual Energy CT and nephrolithiasis

4 59 year old woman Intermittent right flank pain Pain radiates into the right groin Hematuria No abdominal tenderness on exam What does she have? Diagnosis and differential

5 59 yof rt flank pain and hematuria

6 CT findings of nephrolithiasis Dens calculus in the course of the urinary collection system Indirect secondary signs: Dilatation of the upstream collecting system Increases with duration of pain Perinephric fat stranding Includes the peripelvic renal fat

7 35 yof RLQ and rt flank pain

8 US findings of nephrolithiasis Echogenic calculus in the course of the urinary collection system Posterior acoustic shadowing Indirect secondary signs: Dilatation of the upstream collecting system Increases with duration of pain

9 CT or US for suspected nephrolithiasis? Non-contrast helical CT and Ultrasonography Both are appropriate initial imaging modalities. Missed diagnoses resulting in complications are equivalent. Serious adverse events are similar. Return visits to ED are similar. Length of stay in ED is longer when US is done by radiologist. Smith-Bindman R, et al. NEJM (2014): 371;12: 1100

10 CT vs US CT US Sensitivity vs 57 High specificity and positive exam confirms diagnosis Radiation 70% more dose at 6 months 41% needed CT after US Alternate diagnosis in 33% Smith-Bindman R, et al. NEJM (2014): 371;12: 1100

11 42 yof with right sided abdominal pain for several days. Now localizing to RLQ, N/V, WBC 13 tsd, UA: ++ RBC

12 DDx for nephrolithiasis Appendicitis, intestinal obstruction, diverticulitis: No hematuria, usually abdominal tenderness Ovarian torsion, ruptured cyst, dysmenorrhea Billiary colic or cholecystitis No hematuria Less common: Aortic aneurysm Intestinal ischemia Ectopic pregnancy Herpes zoster Hematuria useful disciminator No hematuria in 10-30% of nephrolithiasis, especially when onset of pain more distant

13 43 yom colicy LLQ pain, r/o diverticulitis

14 Treatment of urolithiasis Pain control: NSAIDs If urosepsis: emergent decompression Ureteral stent or nephrostomy Stone < 10 mm: usually passes Treat symptoms Stone > 10 mm: urologic evaluation Extracorporeal Shock Wave Lithotripsy (ESWL) Nephrolithotomy

15 43 yom colicy LLQ pain, r/o diverticulitis Pelvic phlebolith

16 31 yom rt flank pain

17 31 yom rt flank pain

18 CT technique Low dose technique Similar sensitivity and specificity for larger stones Less reliable for stones < 2 mm Less reliable in obese patients BMI > 30 Consider prone scanning position Allows detection of passed stones (dependent location)

19 53 yom rt flank pain, HIV+, on HAART

20 59 yof lt flank pain

21 59 yof lt flank pain

22 59 yof lt flank pain CT KUB from 3 months earlier

23 Staghorn calculi Struvite (Mg ammonium phosphate) or Ca++ carbonate apatite stones Branched stones that fill part or entire renal pelvis Infection stones Strong association with UTIs Urea splitting organisms (Proteus, Klebsiella) Can grow rapidly Deterioration of kidney function End-stage renal disease Urosepsis Surgical treatment often necessary Shock wave lithotripsy Percutaneous nephrolithotomy monfakwei/antlers

24 PV 87 yom s/p fall 10 min delayed

25 Xanthogranulomatous pyelonephritis (XGP, XPN) Renal tissue is replaced: chronic inflammation Dilated calices surrounded by Xanthomatous tissue ( yellow ) Unilateral Necrosis, inflammatory cells: lipid-laden macrophages Giant cells and cholesterol clefts Renal stones, often staghorn stones Infrequent association with renal cancer Peri-renal extension and fistulation Nephrectomy

26 60 yom CP, fall during wheelchair transfer

27 66 yom SCI patient annual surveillance

28 Bladder stones Urinary calculus in bladder Bladder outlet obstruction (e.g. BPH) Foreign body (e.g. urethral catheter) Infections with urea-splitting bacteria Neurogenic bladder

29 20 yof rt flank pain and hematuria

30 20 yof rt flank pain and hematuria Dual Energy CT image

31 Dual Energy (DE) CT Two x-ray sources and 2 data acquisition systems mounted on same x-ray gantry Each x-ray source has independent high voltage generator Allows for independent control of both potential and current E.g.80/ 100 kv & 140 kv Simultaneous low & high energy images can be reconstructed Courtesy S Nicolaou, UBC, Canada Remy-Jardin et al. Radiol Clin North Am Jan;48(1):

32 DE CT exploits X-ray spectrum Xrays: electromagnetic radiation of different wavelenghths: spectrum X-ray spectrum differs by kv x S 1 : 80 kv S 2 : 140 kv + SPS 80 kv 140 kv 140 kv + SPS Tin pre-filtration for 140 kv mm Sn Spectral separation allows characterization of materials photon energy (kev) Courtesy S Nicolaou, UBC, Canada and Siemens

33 Courtesy S Nicolaou, UBC, Canada Principle of Dual Energy CT

34 Principle of DE CT Courtesy S Nicolaou, UBC, Canada and Siemens

35 Material Characterization Materials can be differentiated by applying two X-ray spectra and analyzing attenuation differences. Technique works well for compounds with high atomic numbers taking advantage of the photoelectric effect ~Z 3 Bone Iodine Uroliths Courtesy S Nicolaou, UBC, Canada Johnson T et al. Eur Radiol. 2007; 17:

36 Image Based Methods Modified 2-material decomposition: Characterization of kidney stones Calcified stones are BLUE (heavy ions) Uric acid stones are RED (Nitrogen, Oxygen containing) HU at 80 kv high Z low Z HU at 140 kv Courtesy S Nicolaou, UBC, Canada

37 20 yof rt flank pain and hematuria Calcified stone, mixed composition

38 59 yof rt flank pain and hematuria

39 59 yof rt flank pain and hematuria Uric acid stone

40 DE CT stone characterization Uric acid stones respond well to medical therapy DE ratio around 1.0 Cysteine stones are resistant to ESWL Calcium stones are most common, different types Calcium oxalate monohydrate least susceptible to ESWL DE ratio < 1.4 Other calcium containing stones more fragile: ESWL DE CT can be helpful to in treatment decision making

41 Summary Hematuria? Non-contrast CT and sonography are equivalent first tests Use low dose technique and prone positon for CT Stone size and location is important for treatment DE CT for stone composition

42 Thank you. kingstonegems.com

43 References Ultrasonography versus computed tomography for suspected nephrolithiasis. Smith-Bindman R, Aubin C, Bailitz J, Bengiamin RN, Camargo CA Jr, Corbo J, Dean AJ, Goldstein RB, Griffey RT, Jay GD, Kang TL, Kriesel DR, Ma OJ, Mallin M, Manson W, Melnikow J, Miglioretti DL, Miller SK, Mills LD, Miner JR, Moghadassi M, Noble VE, Press GM, Stoller ML, Valencia VE, Wang J, Wang RC, Cummings SR. N Engl J Med Sep 18;371(12): doi: /NEJMoa PMID: In vivo characterization of urinary calculi on dual-energy CT: going a step ahead with sub-differentiation of calcium stones. Acharya S 1, Goyal A 1, Bhalla AS 1, Sharma R 2, Seth A 3, Gupta AK 1. Acta Radiol Jul;56(7): doi: / Epub 2014 Jun 17. PMID: