Transrectal ultrasonography provides enhanced detection of distal ureteral stones compared to conventional imaging...

Non-contrast computed tomography (CT) is widely regarded as the gold standard for diagnosing ureteral stones; however, CT is not always immediately accessible in all clinical settings. Transrectal ultrasonography (TRUS) enables direct visualization of the distal ureter and may enhance diagnostic confidence during the initial evaluation of suspected distal ureteral stones. This study evaluated the clinical diagnostic performance of TRUS compared with conventional imaging modalities.

This retrospective study included 215 consecutive patients with suspected distal ureteral stones who underwent kidney-ureter-bladder radiography (KUB), intravenous urography (IVU), abdominal ultrasonography (US), and TRUS on the same day. Stone diagnosis was confirmed by spontaneous passage during follow-up (stone-positive group, n = 186), while 29 patients were classified as stone-negative. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for each modality. Comparisons were performed using McNemar's test.

Among stone-positive patients, KUB detected stones in 138 (74.2%), IVU in 148 (79.6%), abdominal US in 129 (69.4%), and TRUS in 184 (98.9%). False-positive findings occurred in six cases with KUB and nine with IVU, whereas none were observed with abdominal US or TRUS. TRUS demonstrated the highest sensitivity (98.9%) and specificity (100%), with a markedly superior NPV (93.5%). TRUS detected distal ureteral stones significantly more frequently than KUB and IVU (both p < 0.001).

TRUS is an effective imaging modality for detecting distal ureteral stones during initial evaluation and may serve as a valuable adjunct, particularly in clinical settings where immediate access to CT is limited.