This article reviews the computed tomography and magnetic resonance imaging (MRI) features of
renal tuberculosis (TB), including TB in transplant recipients and immunocompromised patients. Multi detector computed tomography (MDCT) forms the mainstay of cross-sectional imaging in renal TB. It can easily identify calcification, renal
scars, mass lesions, and urothelial thickening. The combination of uneven caliectasis, with urothelial thickening and lack of pelvic dilatation, can also be demonstrated on MDCT. MRI is a sensitive modality for demonstration of features of renal TB, including tissue
edema, asymmetric perinephric fat stranding, and thickening of Gerota's fascia, all of which may be clues to focal
pyelonephritis of tuberculous origin. Diffusion-weighted MR imaging with apparent diffusion coefficient (ADC) values may help in differentiating
hydronephrosis from
pyonephrosis. ADC values also have the potential to serve as a sensitive non-invasive
biomarker of renal
fibrosis. Immunocompromised patients are at increased risk of renal TB. In transplant patients, renal TB, including tuberculous
interstitial nephritis, is an important cause of graft dysfunction. Renal TB in patients with HIV more often shows greater parenchymal affection, with poorly formed
granulomas and relatively less frequent findings of caseation and
stenosis. Atypical mycobacterial
infections are also more common in immunocompromised patients.