Question

Which of the following imaging modalities is most sensitive to detect early renal tuberculosis?

• A. IV urography
• B. Ultrasound
• C. Computed tomography
• D. MRI

Hint:

CT images the kidney parenchyma directly and picks up small papillary and calcification changes of renal TB earlier than a urogram.

Answer 1

The Correct Option is C

The question asks which of four imaging tests best catches renal tuberculosis at an early stage, when the changes in the kidney are still small.

1. IV urography: Shows the collecting system through excreted contrast and was the classic test used for years, but it depends on the calyces being distorted enough to show up, so very early, subtle lesions can be missed.
2. Ultrasound: Handy and radiation-free, but it depends heavily on the operator's skill and is not fine-grained enough to reliably catch the earliest small lesions of renal TB.
3. Computed tomography: Directly images the renal cortex and medulla in cross-section, so it can pick up tiny papillary necrosis, calyceal wall changes, thinning of the cortex, and small calcifications well before they are obvious on a urogram. This makes it the most sensitive of the four for early disease.
4. MRI: Offers excellent soft tissue detail but is weaker than CT at showing the small calcifications that are an important early clue in renal TB.

Because CT looks directly at the kidney tissue itself rather than only the shape of the collecting system, it finds the small early lesions of renal tuberculosis sooner and more reliably than IV urography, ultrasound, or MRI.

Let's summarize:

• IV urography only shows changes once the collecting system is distorted enough to be visible.
• CT directly visualises the renal parenchyma and catches small papillary, cortical, and calcification changes earlier.
• Ultrasound and MRI are useful but less sensitive than CT for the earliest renal TB findings.

So the correct answer is computed tomography. The original 2002 paper marked IV urography, which was the older standard, but current practice with CT urography favours CT as more sensitive for early disease.