Renal tuberculosis can involve the renal parenchyma and collecting system. Imaging plays an important role in diagnosis. On CT, early manifestations include papillary necrosis resulting in uneven calyceal dilation. Later stages show multifocal strictures throughout the kidney and collecting system. Ultrasound can detect tuberculous granulomas, cavities, and the evolution of lobar caseation over time. Advanced cases on imaging appear as complete lobar calcification, representing end-stage renal tuberculosis.

1. ROLE OF IMAGING IN
RENAL TUBERCULOSIS

2. Renal tuberculosis is a subset of genitourinary
tuberculosis
Tuberculosis can involve both the renal parenchyma
and the collecting system (calyces, renal
pelvis,ureter,bladder and urethra) and results in
different clinical presentations and radiographic
appearances.

3. Clinical presentation
Clinical features are often non specific and include
• Dysuria
• Pyuria
• Back ,flank pain or abdominal pain
• Microscopic or macroscopic haematuria
• Constitutional symptoms
Diagnosis can be obtained by culturing multiple first
morning-void urine samples, or by histology of imaging
guided biopsy or surgical specimens

4. Pathology
• Renal infection results from Haematogenous Spread
at the time of primary infection, with multiple micro-
abscesses developing at the site of periglomerular
capillary seeding.
• Normal Host Immunity is usually able to dampen the
disease with the usual development of a small
inactive granuloma.
• Usually there is a long latency between primary
infection and presentation which in most case occurs
due to host immunity becoming compromised.
• These quiescent granulomas then can reactivate,
grow and eventually communicate with the calyces,
leading to Downstream Infection.

5. Imaging modalities
• Plain radiograph
• Fluoroscopy
• Ultrasound
• CT

7. Pathological changes of renal
tuberculosis

8. Pathological changes of
renal tuberculosis

9. Radiographic features
• Both the renal parenchyma and the upper collecting
system (calyces and renal pelvis) can be involved.
The former is usually seen associated with the latter,
which is the most commonly involved site in the
genitourinary tract.
• Infection limited to the renal parenchyma has two
morphological appearances :
• pyelonephritis
• appearances are similar to pyelonephritis caused by
other organisms
• hypoperfusion and swelling of all or part of the kidney
• pseudotumoural type
• single or multiple nodules
• mimics renal cell carcinoma

10. Calcifications of tuberculosis
(a) Abdominal radiograph demonstrates extensive
calcifications forming a cast of the kidney and ureter.
(b) Photograph of the cut specimen shows complete
replacement of the normal kidney
by inflammatory debris

11. • Plain radiograph revealing classic lobar
pattern of calcification, which is
pathognomonic of end-stage renal
tuberculosis. Ureteral calcification is also
noted

12. Fluoroscopy: IVP
Traditional plain film IVP is quite sensitive to renal tuberculosis with only 10% of affected patients
having normal imaging.
Features include:
• parenchymal scars 50%
• moth eaten calyces: early finding
• irregular caliectasis
• phantom calyx
• hydronephrosis
Lower urinary tract signs also recognised include:
• Kerr kink
• sawtooth ureter
• pipe-stem ureter
• beaded or corkscrew ureter
• thimble bladder

14. Retrograde pyelogram shows that the upper
pole calix is stenotic (arrow) with associated
papillary necrosis.
The adjacent calix is fibrotic and distorted as
well.
Collimated image from intravenous
urography demonstrates
multiple papillary cavities.

15. intravenous urogram revealing the ‘classic’ lobar pattern of
calcification in a non-functioning (R) kidney

16. (R) ureteric stricture (white arrow) with ureteric calcification
(black arrowheads), pseudo-calculi (black arrow), and irregular
calcification in the parenchyma (circled area)

17. an upward pointing
(arrow) renal pelvic
calculus, suggesting
the presence of a hiked
up renal pelvis.
Multiple discrete
calcifications are
noted in an upper
polar tuberculosis
cavity (circled area)

18. (A) Intravenous urogram revealing lower infundibular (arrow) and renal pelvic scarring
(curved arrow). Note areas of papillary necrosis in the circled area, (B) Intravenous
urogram revealing papillary necrosis in the upper group of calyces, with irregularity of
the calyceal margins and the lateral margin of the upper infundibulum (dotted circle),
indicating spread of infection from the calyx to the infundibulum. (Healing forniceal
papillary necrosis of non-tuberculosis origin noted in a lower calyx (arrow), (C)
Intravenous urogram revealing multiple parenchymal cavities (black arrows) with areas
of papillary necrosis (white arrow) in the upper group calyces, bilaterally. The (L) upper
group (lateral division) calyceal outline is destroyed by adjacent granulomatous tissue
(arrowheads)

19. Bilateral percutaneous nephrostomogram revealing multiple filling
defects along the upper ureter, bilaterally, representing sumucosal
granulomas (empty arrowheads). The large filling defect noted in the (R)
ureter is a calculus (white arrow). The high density of the contrast in the
collecting systems is obscuring the sumucosal granulomas; however,
irregularity along the medial pelvic margin gives a clue to the presence of
the same (solid arrowheads)
normal

20. (A) Intravenous urogram revealing a non-functioning (L) kidney and a
small capacity urinary bladder. The combination is suggestive of a
tuberculosis origin for the non-function, (B) Intravenous urogram
revealing non-functioning (R) kidney. (L) Renal pelvic and upper
infundibular scarring (white arrowheads), resulting in uneven caliectasis.
A (L) lower ureteric stricture (arrow) and small capacity bladder (black
arrowheads)

21. Pyelo-cavitatory (arrowheads) and pyelolymphatic
reflux (arrows) noted on retrograde pyelography

22. Intravenous urogram revealing right upper infundibular (arrow)
and calyceal strictures, with cortical scarring. Pyelosinus
extravasation of contrast in the (L) kidney (arrowheads) suggests
the presence of fragile calyces

23. Delayed phase of intravenous urogram with a non-functional (L) kidney opacified retrogradely: Developing
lobar caseation in the U/3 of the (L) kidney (black arrowheads).
Note assimilation of the dilated calyces into the renal parenchyma.
Ragged hydrocalicosis(indicative of marked urothelial thickening) noted in the lower half of the (L) kidney
(arrows). Parenchymal demarcation is still clear adjacent to the same
(dotted line represents the non-visualized left renal outline).
(R) renal papillary necrosis is also seen (circled area) and so are calcified (L) paraspinal lymph nodes (white
arrowheads)

24. (A) Intravenous urogram revealing calcified (L) psoas abscess (black arrow), impinging
on the ureter and a calcified caseous renal mass
(arrowheads); more apparent on nephrotomography (B)

25. Ultrasound
Ultrasound is less sensitive than CT in detection of:
• calyceal, pelvic or ureteral abnormalities.
• isoechoic parenchymal masses.
• small calcifications.
• small cavities that communicate with collecting system.

26. usg
• (A) USG revealing
tuberculosis
granulomas of varying
sizes (white arrows),
• (B) USG revealing
larger granulomas–
the granulomas are
highlighted by the
vascular “cut-off”
(white arrows) noted
on this color flow
image

27. (A) High-resolution ultrasound images (acquired with a 7.5 MHz transducer)
demonstrate a small irregular caseous cavity (white arrow) in the upper part
of the left renal parenchyma,
(B) high-resolution ultrasound images revealing a tuberculous cavity with fine
septae within, in the lower part of the left kidney of another patient. Note
marked urothelial thickening in this dilated system,
(C) USG image revealing irregular sonolucent cavities, with a semisolid echo
texture

28. • (A) USG image revealing a
caseating tuberculous
granuloma,
communicating with a
calyx via a narrow tract
(white arrows), (B) USG
image revealing a large
thick walled caseated
tuberculous cavity
communicating with the
upper calyx (arrowheads).
Small granulomas are
noted inferior to this cavity
(arrows)

29. (A) USG image revealing hyperechogenic areas of caseation interspersed
with the echogenic sinus echoes. (coronal scan), (B) Oblique USG scan
reveals uneven caliectasis (white arrows) with a hazy interface and
urothelial thickening in the upper calyces. The lower calyceal region is
replaced by hyperechogenic caseous tissue, (C) Comparative USG image of
regular (evenly dilated) caliectasis with hyperechoic fungal balls (white
arrows) in a HIV-positive patient (note the hyperechogenic material is
lying within clearly dilated calyces and are not replacing them as happens
in tuberculous caseation)

30. • (A) Moderate-to-severe
urothelial thickening noted
throughout the visualized
urothelium. This is well
visualized on account of the
dilatation due to a
tuberculous ureteric
stricture, (B) USG image
revealing uneven caliectasis
with ragged urothelial
thickening (arrowheads).
Note significant debris in
the lower calyces

31. USG image showing evolution of tuberculous lobar caseation.
Different phases of destruction are apparent. (Lower group calyces
are completely merged with the parenchyma, midgroup calyces about
to merge, and upper ones almost merged). Arrowheads demarcate the
junction between residual parenchyma and the dilated calyces

32. (A) USG image revealing caseation with a developing lobar
pattern of calcification, in almost all calyces, barring the lower
group of calyces (white arrow) (B) USG image revealing classic
“lobar calcification”- pathognomonic of renal tuberculous (C)
USG image revealing a densely calcified kidney producing
acoustic shadowing that obscures underlying details. White
arrows point to junctions between the renal lobes

33. (A) USG image revealing
lobar caseation (A) Grey
scale and,
(B) Color flow image
demonstrating presence of
renal vasculature only
between the caseated
lobes

34. • (A) USG image revealing left
tuberculous perinephric
collection due to a ruptured
upper polar tuberculous
abscess. (A) Grey scale
image, (B)
• USG image revealing left
tuberculosis perinephric
collection due to a ruptured
upper polar tuberculous
abscess. Color flow image
revealing
• lateral extent of the renal
parenchyma

35. CT
• CT is the most sensitive modality for visualising renal
calcifications and CT IVP is more sensitive at identifying all
manifestations of renal tuberculosis .
• early
• papillary necrosis (single or multiple) resulting in uneven
caliectasis
• progressive
• multifocal strictures can affect any part of the collecting system
• generalised or focal hydronephrosis
• mural thickening and enhancement
• poorly enhancing renal parenchyma, either due to direct
involvement or due to hydronephrosis
• endstage
• progressive hydronephrosis results in very thin parenchyma,
mimicking multiple thin walled cysts
• amorphous dystrophic calcification eventually involves the entire
kidney (known as putty kidney)

36. CT
• Renal
tuberculosis.
Contrast
enhanced
nephrographic
phase CT shows
dilated calices
and thining of
the renal cortex
with thin
calcifications.

37. CT revealing parenchymal granulomas (black arrows) in
the (L) kidney with uneven caliectasis and ureterectasis accompanied
by urothelial thickening (white arrow). Note the hypoperfused renal
parenchyma and complete loss of corticomedullary differentiation in
the (L) kidney

38. • (A) Nephrographic and (B)
pyelographic phase of CT:
Showing a peripherally
enhancing granuloma (arrow) in
a horseshoe kidney.
• Diffuse inflammation mimicking
a lobar nephronia-like
appearance is also noted, with
perinephric extension (circled
area).
• Note loss of corticomedullary
differentiation in (A) in the left
third of this kidney

39. Lobar nephronia
• Lobar nephronia refers to an intermediate stage
between acute pyelonephritis and renal abscess, and is a
focal region of interstitial nephritis.
• It appears as a wedge of poorly perfused renal parenchyma,
without a cortical rim sign.

40. CT revealing caseous TB cavity (arrow) in the upper
pole of the (L) kidney: (A) axial and (B) coronal sections (MIP image).
Note non-functioning hydronephrotic (R) kidney, with a scarred renal
pelvis, in (B), which is a delayed scan

41. Axial CT revealing tiny granulomas (arrows) in both
kidneys, better appreciated on the (R). A left renal abscess with
perinephric extension. Note bilateral fascial thickening (arrowheads),
additional (B) axial and (C) coronal CT images revealing site of rupture into
the perinephric space (arrows). Drainage catheters are noted bilaterally

42. CT revealing Left TB renal
abscess (arrow) with
minimal perinephric spread
(arrowheads) in (A). The left
psoas muscle
is involved, better appreciated
in (B), Retroperitoneal fascial
thickening,
fat stranding, and small left
paraaortic lymph nodes are also
noted
with a loss of corticomedullary
differentiation of the affected
area in
the (L) kidney

43. CT revealing (A) focal renal cortical scarring (arrows)
and (B) focal cortical thinning (C) diffuse cortical scarring of the (L) renal
cortex. Renal pelvic scarring and resultant caliectasis are also noted

44. (A)Non-contrast CT image showing fine cortical calcification in the (L) kidney (white
arrow).
(B)The cavity (arrowheads) was communicating with the PCS. The urothelial thickening
(black arrow) is also well appreciated.
(B and C) non-contrast CT image showing punctate calcification [arrows in (B) and soft
(caseous) parenchymal calcification arrowheads in (C)].
(D and E) axial CT revealing the lobar pattern of calcification (arrowheads)

45. CT revealing multiplicity of
findings in urinary TB-uneven
caliectasis with no obvious
pelvic dilatation, parenchymal
scarring
(black arrow), cavity
communicating with PCS
(white arrow), urothelial
thickening and multiple
ureteral strictures (black
arrowheads)

46. (A) Axial and (B) coronal CT images revealing lobar
caseation of the (L) kidney. Note assimilation of the calyces into the renal
parenchyma. The calyces in the (R) sided hydronephrosis communicate
with each other and are clearly demarcated from the renal parenchyma.
Note the stricture of distal ureter with resultant proximal dilatation

47. MRI
Fat-saturated T2W FSE sequence MRI image showing
multiple small hypointense granulomas (thin white arrows) in the (R)
kidney. The (L) kidney shows caliectasis with heterogeneous intermediate
signal within on T2W images, due to caseous internal debris (thick arrow)

48. Fat-saturated T2W FSE sequence MRI image showing
small, slightly hyperintense, caseating granulomas (curved arrows),
and a tiny hypointense non-caseating granuloma (arrow)

49. (A) axial fat-saturated T1W FSE, (B) Coronal fat-saturated T2W FSE sequence and (C) post-contrast axial T1 fat-
saturated MRI images of the patient reveals multilocular cystic appearance in a case of tuberculous
pyonephrosis on right side.
There is significant global thinning of the renal parenchyma. The cystic lesions are predominantly hyperintense,
but reveal multiple scattered areas of intermediate signal within, along with few septae (black arrow).
The left upper pole renal lesion appears slightly hyperintense on T2-weighted images suggestive of a focal area of
caseous necrosis (white arrow)

50. (A) axial and (B) coronal fat-saturated T2W FSE
sequence and (C) post-contrast axial T1 fat-saturated MRI imagesshowing
a TB cavity (arrowheads) communicating with dilated calyces.
Note small peripheral non-enhancing hypointense lesion, suggestive of a
granuloma (white arrow). An enlarged pyramid is also noted (black arrow)

51. Fat-saturated T2W coronal MRI image of TB
pyonephrosis revealing a scarred renal pelvis and
marked dilatation of the collecting
system with severe parenchymal loss

52. Angiography
• Renal angiography shows no specific vascular changes in
renal TB.
• The vessels appear normal in the early case,
• while in the more advanced case, there may be zones of
irregularity (especially of the interlobar and arcuate
arteries) and even complete occlusion.
• In instances of TB pyonephrosis, angiography reveals the
appearance of hydronephrosis.

53. • Angiography is of greater help in determining how much
viable renal tissue remains and in the planning of partial
nephrectomy than it is in the specific diagnosis of TB.

54. Differential diagnosis
General imaging differential considerations include:
• papillary necrosis
• medullary sponge kidney
• TCC (transitional cell carcinoma) of renal tract
• SCC (squamous cell carcinoma) of renal tract
• xanthogranulomatous pyelonephritis (XGP)

55. Thank you