Imaging approach of renal diseases in immuno-compromised patients

1. Imaging approach of renal diseases in immuno-compromised patients Jacques le Roux 11/05/2012

2. The patients • The diseases • Approach • - clinical • - imaging options • - imaging approach

3. THE PATIENTS • The prototype – HIV/AIDS • 2. Any chronic disease e.g. • Cancer • - multiple myeloma • - leukaemia (most common malignant cause of bilateral ↑ kidneys) • - lymphoma (usually NHL) – kidney very common extranodal site • Collagen vasc diseases e.g. SLE (lupus nephritis) • DM • Chemoradiotherapy • 4. Transplant patients e.g. kidney, bone marrow

4. THE DISEASES • A. NEPHROPATHY • This is the diff Δ of renal failure – Pre, renal, post renal • Renal: (parenchyme disease) • Imaging can suggest a diagnosis • - the delayed (persistent) nephrogram/↑echos • Diagnosis remains histological e.g. • 1. Acute Tubular Necrosis - oedema • Most common cause of acute renal failure • Due to: • - drugs: Haart, antibiotics (AMPH B), contrast (Iodine), chemotherapy • - ischemia (renal art stenosis) • - renal transplant rejection • 2. Glomerulosclerosis – cell proliferation • DM, Lupus Nephritis • 3. Nephrocalsinosis - Calcifications • Hypercalcemia

5. B. RENAL INFECTIONS • 1. Acute pyelonephritis - DM (E.coli) • 2. Emphysematous pyelonephritis – gas forming • organisms - life threatening,DM • 3. Chronic pyelonephritis - reflux , obstruction (stones) • 4. Opportunistic infections – AIDS related • Pneumocystis jiroveci • TB, MAI (mycobact avium intracellulare) • Fungi (candida, aspergillus) • C. RENAL TUMORS • I.Non AIDS-related in imm. compr. patients • Non Hodgin Lymphoma • Leukemia • M. Myeloma • II.AIDS-related • NHL • Kaposi • RCC ( 8 times more)

6. D. DRUGS (AIDS RELATED)– HAART • 1. Direct(nephrotoxic) • - Nephropathy (ATN) • - Stones (dark) - Indinavir • - FANCONI syndrome (tubular dysfunction) • Kidney cannot reabsorb – glucose, amino acids, phosphate • Compl. Osteopenia - rickets • - osteomalacia • 2. Indirect– insulin resistance • ↑Colesterol→ renal art. stenosis→ HT • DM

7. APPROACH • Clinical: - history, renal function (↑ creat.) • Imaging options: • 1. ULTRASOUND - choice for screening (size, hydronephrosis) • Size 9-13 cm • Central echo complex(renal sinus) – dominates sonar picture • - Contains: - fat (↑echos), vessels • - renal pelvis (colleting system) • - surrounded by parenchyma • Parenchyma • 1 Cortex – similar or ↓echos compare to liver • 2 Medullary pyramids - ↓ egos (sonolucent) compare to cortex • - rounded or cone shape as they bulge into complex • Difference between cortex and medulla echos creates cortex-medulla differentiation • Color doppler – venous involvement of renal tumors

8. RENAL PARENCHYMA (NORMAL KIDNEY) • ADULT • Parenchyma equal or ↓ echo as liver • Central Echo Complex ↑ echo • NEONATE • Cortex - ↑ echo compared with liver • - Pyramids look like hydroneph

9. CT = choice for renal tumours (replaced KUB and IVP) • Precontrast – think gasses, masses, stones, bones • The 3 phases with contrast (CT -IVP) • i Corticomenullary (early arterial 20 – 90 sec) • - cortex enhances before medulla • - diff between them • ii Nephrogram ( 2 – 3 minutes) • - renal parenchyma uniformly enhance • - size, symmetry, contour, density, parench loss • iii Pyelogram – excretory (5 - 15 minutes) • - opacity collecting system • calyces cupped or clubbed • 3D for art and venous structures • 3 NM (frans en gerrit se speelveld) • DTPA (glom. function) • MAG 3 (tubular function) • DMSA anatomy (stays in cortex) e.g. • - scar tissue – pyelonephr. • Massas • 4 MRI – if contraindication

10. IMAGING APPROACH • KIDNEYS • BILAT RENAL DISEASE UNILATERAL • (Systemic-medical) (Focal-surgery) • Acute: Bilat. Large >13cm Chronic (end stage): bilat small <9cm • e.g. immuno compromised e.g. HT, DM • A. Nephropathy – is parenchyme disease (Edema, renal failure) • US CT • - Large kidneys and smooth - ↑kidneys • - ↑echo – parenchyma - Precontrast - ↑Att medulla (prot in tubuli) • (cortex more than liver) - Delayed nephrogram or striated • Loss of diff. (stripes in cortex is dilated tubuli with contrast - no • ↓echo-renal sinus fat uniform enhancem)

11. NEPHROPATHY • Large kidney (13cm) • ↑Echo – parenchyma • ↓Echo renal sinus fat • Loss of diff. RENAL FAILURE • Both kidneys small (< 9cm) • ↑ echo in parync. compared liver

12. AIDS NEPHROPATHY – MEDULLARY NEPHROCALCINOSIS • Medulla pyramids ↑ echo • Cortex and columns of Bertin (cortex between pyramids) normal

13. B. RENAL INFECTIONS • ACUTE PYELONEPHRITIS – CT with contrast • Wedges of ↓Att (edema) • Striated nephrogram • ACUTE PYELONEPHRITIS - US • Focal area ↑ echo PERIRENAL ABSCESS - CT • ↓ Att (fluid) • Gas bubbles • RENAL ABSCESS - US • Cystic mass with internal heterogeneous ↑echo fluid (debri)

14. EMPHYSEMATOUS PYELONEPHRITIS (GAS) X-RAY Striations in parenchyma – is gas in collective system

15. CHRONIC PYELONEPARITIS (REFLUX NEPHROPATHY) IVP Blunted calyx with overlying scar

16. END STAGE RENAL TB R Small and calcified L Compensatory hypertrophy

17. OPPORTUNISTIC INFECTIONS– IMAGING NON SPECIFIC • Pneumocystis jiroveci (fungus) MAI, CMV • - small cortical calcifications • - nephrocalcinosis • striated nephrogram • Fungi (candida, aspergillus) • - micro abscesses • hydronephrosis (fungal ball) • TB (renal second most common) ,from lungs • - Acute - abscesses • - Chronic - small scared KIDNEY,Ca++ ,strictures (ureters)

18. CANDIDA ALBICANS Pyonephrosis Nephrostomy in left kidney - previous hydronephrosis

19. RENAL ABSCESS – LEFT KIDNEY Pyelogram (excretory) Low att. mass with decreased excretion of contrast

20. TB ABSCESS - CT WITH CONTRAST Low att. with Ca⁺⁺

21. RENAL TB - IVP • R Hydronephrosis • Stricture mid uret

22. C. RENAL TUMORS IN IMMUNE COMPROMISED PATIENTS • Look for other sites of involvement • I. NON AIDS-RELATED • 1. Non Hodgkin lymphoma • Kidney very common site for extra nodal lymphoma • Renal parenchyma contains no lymph. tissue - comes from retroperitoneal nodes, renal • capsule (rich lymph vessels) or with blood/hematogeneous • Lesion (75% bilat.) • Classic: - large kidneys • Tumor surrounds kidney without compression of parenchyma • Encase blood vessels but lumen remains open • No thrombosis of IVC or renal vein • Enhance less than parenchyma • 2. Leukaemia • Most common cause of bilat. ↑ kidneys • Chloroma – focal mass in cortex • 3. M. Myeloma • Nephrocalsinosis - Hypercalcemia • Punched lytic bone lesions

23. NON AIDS-RELATED LYMPHOMA (NHL) • Coronal – CT with contrast • Bilat ↑ • No enhancement - homogenous

24. II. AIDS RELATED • 1 NHL • Usually multiple nodules • Solitary lesions • 2 KAPOSI • Rare in kidney – skin lesions • ↓Att • 3 RCC (8 times more) • Hypervascular • Trombosis – IVC, renal vein

25. RCC Solid ↑ echo mass (upper pole)

26. AIDS – RELATED LYMPHOMA Solitary mass – poor enhancement

27. DRUGS ---- HAART (INDINAVIR) - CALCULI ARE DARK - NO IMAGING SUPERIOR • SONAR - CALCIFIC FOCI • - If you see calculi – calcium, uric-acid, in this case was not • related to indinavir • Indirect signs • - Hydronephrosis in the absence of calculi

28. FANCONI SYNDROME WITH RENAL FAILURE • Bone scan – T99-MDP • Diffuse bone uptake • Kidney no uptake – kidney failure (no function)

29. L RAS - MRA

30. RAS - DOPPLER • Intrarenal art – Tardus parvus waveform • Parvus ↓ systolic peak • Tardus delayed before systolic peak • Main renal art - systolic peak ↑

31. RENAL TRANSPLANT ANATOMY • Kidney • R Iliac fossa – extraperit • Vessels – iliac (ext or common) • Ureter – trigone • Imaging • Choice - US - grayscale, doppler • - NM - MAG 3 • Additional - CT – anatomy,VASC, 3 phases • - MRI – contra indications

32. COMPLICATIONS • ↓ Kidney function(parenchyme disease) • 1. ATN – ischaemia, first week • 2. Rejection • Hyperacute – minutes • Acute – after 1 week • Chronic – after months • 3. Drugs (nephrotoxic) – Pat. Becomes ↓ immune • Cyclosporine – after 1 month • Post transplant lymphoproliferate diseases • (a) Lymphoma • (b) RCC • (c) Kaposi • IMAGING ↓ Kidney Function • US – grayscale (as before), egos,diff • NM - ATN – normal perfusion, ↓ excretion • - Rejection and cyclosporin - ↓ perfusion and excretion • To diff between ATN, rejection, cyclosporin • - Do biopsy (US or CT guidance)

33. B.Fluid collections- HAUL • 1. Hematoma – first day • 2. Abscess (fever) – first week • 3. Urinoma – first month • 4. Lymphocele – after one month • ** NM - Urinoma – takes up tracer – is in urine • - Lymphocele - no uptake (cold) • - usually – ureter-bladder junction • C. Vascular • 1. Prerenal – RAS, RA thrombosis • 2. Post renal – RVS, RV thrombosis • 3. Complications due to biopsy: • - AVF • - Pseudo aneurysm • If you suspect above named – do convent. angiography for stents (RAS) • - Thrombectomy (RV thrombosis) • - Embolization (AVF)

34. URINOMA Uptake of tracer LYMPHOCELE No tracer uptake • ATN • Normal perfusion • ↓ excretion

35. PULSE DOPPLER (SPECTRAL WAVE FORM) • Normal graft - low resistance waveform • - flow in sist and diast. • Acute rejection – end-diastolic flow absent • - high RI >.8 • Art. flow reversed in diast. • ?Severe rejection / ?ATN / ?renal vein thromb • - ΔΔ from renal vein thrombosis • Color Doppler – vein patent • Biopsy showed rejection

36. RENAL VEIN THROMBOSIS • Art. flow reversed in diast. (plateau) • No venous signal in vein PSEUDOANEURYSM Mid ren art– forward and reverse flow Do conv. angio • AVF • Turbulent flow • CT showed early filling of vein • Do conv. angio

37. References 1. Symeonidou C, Imaging And Histopathology Features Of HIV Related Renal Disease, Radiographics 2008; 28: 1339 – 1354. 2. Daneman A, Renal Pyramids Focused Sonography Of Normal And Pathologic Processes, Radiographics 2010; 30: 1287 – 1307. 3. Brandt WE, Fundamentals Of Diagnostic Radiology 3rd ed. 874 – 908. 4. Brown E, Complications Of Renal Transplantation: Evaluation With US And NM, Radiographics 2000; 20: 607 – 622.