Imaging approach of renal diseases in immuno-compromised patientsJacques le Roux11/05/2012

The patients

The diseases

Approach - clinical- imaging options- imaging approach

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 siteCollagen vasc diseases e.g. SLE (lupus nephritis)DM

Chemoradiotherapy

4. Transplant patients e.g. kidney, bone marrow

THE DISEASES

A. NEPHROPATHYThis is the diff of renal failure Pre, renal, post renal Renal: (parenchyme disease)Imaging can suggest a diagnosis- the delayed (persistent) nephrogram/echosDiagnosis remains histological e.g.

1. Acute Tubular Necrosis - oedemaMost common cause of acute renal failureDue to:- drugs: Haart, antibiotics (AMPH B), contrast (Iodine), chemotherapy- ischemia (renal art stenosis)- renal transplant rejection

2. Glomerulosclerosis cell proliferationDM, Lupus Nephritis

3. Nephrocalsinosis - CalcificationsHypercalcemia

B. RENAL INFECTIONS1. Acute pyelonephritis - DM (E.coli)2. Emphysematous pyelonephritis gas forming organisms - life threatening,DM3. Chronic pyelonephritis - reflux , obstruction (stones)4. Opportunistic infections AIDS relatedPneumocystis jiroveci TB, MAI (mycobact avium intracellulare)Fungi (candida, aspergillus)

C. RENAL TUMORSI. Non AIDS-related in imm. compr. patientsNon Hodgin LymphomaLeukemiaM. MyelomaII. AIDS-relatedNHLKaposiRCC ( 8 times more)

D. DRUGS (AIDS RELATED) HAART

1. Direct (nephrotoxic)- Nephropathy (ATN)- Stones (dark) - Indinavir- FANCONI syndrome (tubular dysfunction)Kidney cannot reabsorb glucose, amino acids, phosphateCompl. Osteopenia - rickets - osteomalacia

2. Indirect insulin resistanceColesterol renal art. stenosis HTDM

APPROACH

Clinical: - history, renal function ( creat.)

Imaging options:

1. ULTRASOUND - choice for screening (size, hydronephrosis)Size 9-13 cmCentral echo complex (renal sinus) dominates sonar picture- Contains: - fat (echos), vessels - renal pelvis (colleting system) - surrounded by parenchymaParenchyma1 Cortex similar or echos compare to liver2 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 differentiationColor doppler venous involvement of renal tumors

RENAL PARENCHYMA (NORMAL KIDNEY)ADULTParenchyma equal or echo as liverCentral Echo Complex echo

NEONATECortex - echo compared with liver - Pyramids look like hydroneph

CT = choice for renal tumours (replaced KUB and IVP)Precontrast think gasses, masses, stones, bonesThe 3 phases with contrast (CT -IVP)i Corticomenullary (early arterial 20 90 sec)- cortex enhances before medulla- diff between themii Nephrogram ( 2 3 minutes)- renal parenchyma uniformly enhance- size, symmetry, contour, density, parench lossiii Pyelogram excretory (5 - 15 minutes)- opacity collecting system calyces cupped or clubbed3D 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

IMAGING APPROACH

KIDNEYS

BILAT RENAL DISEASE UNILATERAL (Systemic-medical) (Focal-surgery)

Acute: Bilat. Large >13cm Chronic (end stage): bilat small

NEPHROPATHYLarge kidney (13cm)Echo parenchymaEcho renal sinus fatLoss of diff.RENAL FAILUREBoth kidneys small (< 9cm) echo in parync. compared liver

AIDS NEPHROPATHY MEDULLARY NEPHROCALCINOSISMedulla pyramids echoCortex and columns of Bertin (cortex between pyramids) normal

ACUTE PYELONEPHRITIS - USFocal area echoRENAL ABSCESS - US Cystic mass with internal heterogeneous echo fluid (debri)B. RENAL INFECTIONSACUTE PYELONEPHRITIS CT with contrastWedges of Att (edema)Striated nephrogramPERIRENAL ABSCESS - CT

Att (fluid)Gas bubbles

EMPHYSEMATOUS PYELONEPHRITIS (GAS)X-RAYStriations in parenchyma is gas in collective system

CHRONIC PYELONEPARITIS (REFLUX NEPHROPATHY)IVPBlunted calyx with overlying scar

END STAGE RENAL TB R Small and calcifiedL Compensatory hypertrophy

OPPORTUNISTIC INFECTIONS IMAGING NON SPECIFIC

Pneumocystis jiroveci (fungus) MAI, CMV- small cortical calcifications- nephrocalcinosisstriated nephrogram

Fungi (candida, aspergillus)- micro abscesseshydronephrosis (fungal ball)

TB (renal second most common) ,from lungs- Acute - abscesses- Chronic - small scared KIDNEY,Ca++ ,strictures (ureters)

CANDIDA ALBICANSPyonephrosisNephrostomy in left kidney - previous hydronephrosis

RENAL ABSCESS LEFT KIDNEYPyelogram (excretory)Low att. mass with decreased excretion of contrast

TB ABSCESS - CT WITH CONTRASTLow att. with Ca

RENAL TB - IVP R Hydronephrosis Stricture mid uret

C. RENAL TUMORS IN IMMUNE COMPROMISED PATIENTSLook for other sites of involvement

I. NON AIDS-RELATED

1. Non Hodgkin lymphomaKidney very common site for extra nodal lymphomaRenal parenchyma contains no lymph. tissue - comes from retroperitoneal nodes, renal capsule (rich lymph vessels) or with blood/hematogeneous Lesion (75% bilat.)Classic: - large kidneysTumor surrounds kidney without compression of parenchymaEncase blood vessels but lumen remains openNo thrombosis of IVC or renal veinEnhance less than parenchyma

2. LeukaemiaMost common cause of bilat. kidneysChloroma focal mass in cortex

3. M. Myeloma Nephrocalsinosis - HypercalcemiaPunched lytic bone lesions

NON AIDS-RELATED LYMPHOMA (NHL)Coronal CT with contrastBilat No enhancement - homogenous

II. AIDS RELATED

1 NHLUsually multiple nodulesSolitary lesions

2 KAPOSIRare in kidney skin lesionsAtt

3 RCC (8 times more)HypervascularTrombosis IVC, renal vein

RCCSolid echo mass (upper pole)

AIDS RELATED LYMPHOMASolitary mass poor enhancement

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

FANCONI SYNDROME WITH RENAL FAILUREBone scan T99-MDPDiffuse bone uptakeKidney no uptake kidney failure (no function)

L RAS - MRA

RAS - DOPPLERIntrarenal art Tardus parvus waveformParvus systolic peak Tardus delayed before systolic peak Main renal art - systolic peak

RENAL TRANSPLANTANATOMYKidneyR Iliac fossa extraperitVessels iliac (ext or common)Ureter trigone

ImagingChoice - US - grayscale, doppler - NM - MAG 3Additional - CT anatomy,VASC, 3 phases - MRI contra indications

COMPLICATIONS

Kidney function (parenchyme disease)

1. ATN ischaemia, first week 2. RejectionHyperacute minutesAcute after 1 weekChronic after months

3. Drugs (nephrotoxic) Pat. Becomes immuneCyclosporine after 1 monthPost transplant lymphoproliferate diseases(a) Lymphoma(b) RCC(c) KaposiIMAGING Kidney FunctionUS grayscale (as before), egos,diffNM - ATN normal perfusion, excretion - Rejection and cyclosporin - perfusion and excretionTo diff between ATN, rejection, cyclosporin- Do biopsy (US or CT guidance)

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)

URINOMAUptake of tracerLYMPHOCELENo tracer uptakeATNNormal perfusion excretion

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

- from renal vein thrombosisColor Doppler vein patent

Biopsy showed rejection

RENAL VEIN THROMBOSISArt. flow reversed in diast. (plateau)No venous signal in veinPSEUDOANEURYSMMid ren art forward and reverse flowDo conv. angioAVFTurbulent flowCT showed early filling of veinDo conv. angio

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.