Which is the most sensitive imaging modality to detect early renal tuberculosis?

The most sensitive imaging modality to detect early renal tuberculosis is intravenous urography. Earliest urographic findings in renal TB is irregular calyceal contour which occur secondary to papillitis. Characteristic urographic finding in renal TB is 'phantom calyx' which refers to an obstructed, nonfunctional calyx proximal to an infundibular stricture. Early signs of ureteral TB includes dilation, ulceration and mucosal irregularity. Ref: Diagnosis of Genitourinary Disease By Main I. Resnick, 2nd Edition, Pages 289-90