1. By: Dr Rekha Khare
MD Radiology

2. Clinical Presentation…..
 A 25 year young man came to the
x-ray department for ultrasound exam
 Complaints:
- rapid onset of high fever
- painful mass right flank

3. Ultrasound findings…..
Enlarged right kidney with dilated
pelvis with no hydrocalyx
Indistinct hypoechoic inferior pole

4. U/S finding contd…..
Huge heterogenous hyperechoic
perinephric mass lesion all over
involving inferior pole too
Bulky right psoas muscle

5. CECT as further imaging
Bulky right kidney with focal
non enhancing hypodense area
lower pole not sparing the
peripheral cortical rim
(renal infarction-cortical rim sign +ve)

6. CECT finding contd…..
Huge multi septate hypodense
soft tissue thickening mimicking
mass in perinephric space having
few small fluid collection involving
inferior pole also

7. CECT findings contd…..
Bulky right psoas muscle with
some hypodense lesion? collection
Mild hepatomegaly

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25. Clinical diagnosis…..
Acute pyelonephritis with severe
perinephric inflammation with
some fat stranding
no ureteric calculus 0r obstructive pathology

26. What is perinephric space?
Cone shaped retroperitoneal
compartment containing
kidney, adrenal, fat, fibrous
bridging septa & rich net work
of perirenal vessel & lymphatic

27. How PNS gets involve?
From outside lesion via -lymphatic
-direct
- in malignancy or infection
From inside renal lesion
-acute process, injury to the kidney,calyceal
rupture in acute ureteric obstruction

28. What is perinephric stranding?
It is linear areas of abnormal
increased attenuation in soft
tissue/ fat- resulting from:
- acute renal inflammatory or infective
lesion with NO HYDRONEPHROSIS
- calyceal rupture in acute ureteric
obstruction with HYDRONEPHROSIS

29. D/D perinephric mass lesion…..
Perinephric abscess/ urinoma/
hematoma
Mass/ lymphoma/ Tumour
Misc.…. Proliferative disease

30. Acute pyelonephritis…..
 It is an infection of renal parenchyma
usually caused by an ascending infection
from lower urinary tract
 Most common offending pathogen E.coli
 It is almost always curable with antibiotic
 No lasting damage to kidney

31. Case review after a month…..
Symptomatic relief
Advised: repeat U/S & CECT

32. Ultrasound after a month….
Minimal residual ill defined
right renal inferior pole
Perinephric space appears
clear

33. CECT after a month…..
Minimal residual lesion at
right renal lower pole
Perinephric space clear

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41. Case review after3 months…..
Patient fit and fine
On follow up imaging--
-no residual lesion on
ultrasound and plain CT scan

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46. Role of imaging…..
Imaging required to exclude-
-obstructed kidney
-previous renal pathology
-mass lesion
-high risk patient
Acute pyelonephritis: clinico-pathological
diagnosis

47. Follow up Imaging…..
Not really essential
Imaging changes can take
3-6 months to resolve
complication

48. References…..
1. Acute bacterial pyelonephritis
Dr Yuranga Weerakkody and Dr Frank Gaillard et al
Radiopaedia.org
2. Differential Diagnosis of Perinephric Masses on
CT and MRI
Antonio Westphalen, Benjamin Yeh, Aliya Qayyum,
Anil Hari and Fergus V. Coakle
American Journal Of Roentgenology,2004;183:1697-1702