UNENHANCED HELICAL COMPUTERIZED-TOMOGRAPHY FOR THE EVALUATION OF PATIENTS WITH ACUTE FLANK PAIN

Purpose: We determined the value of unenhanced helical computerized to mography (CT) in the diagnosis of acute flank pain in 105 patients eva luated for suspected stone disease. Materials and Methods: Noncontrast ed spiral GT was done in 105 consecutive patients seen in our emergenc y department to evaluate acute flank pain. All CT studies were reviewe d for the presence of ureteral or renal calculi, perinephric or periur eteral stranding, presence and degree of pelvicalicectasis or other ra diological findings. If necessary, an excretory urogram was performed to confirm the presence or absence of urinary stones. Patients were fo llowed to determine clinical outcome including the need for urological intervention. Results: Of the 49 patients determined to have stones 2 4 (49%) had spontaneous stone passage, 10 (20%) had improved symptoms without documented stone passage and 14 (29%) required surgical interv ention. In 29 of 51 patients (57%) with negative CT readings for stone disease a diagnosis was established by other intra-abdominal findings . In 21 patients (41%) no clinical diagnosis could be established, and 1 scan in a patient with a distal ureteral calculus was interpreted a s falsely positive. These findings yielded a sensitivity of 98%, speci ficity 98% and overall accuracy 96% for diagnosing ureteral stones. Co nclusions: Despite the limitations of helical CT in evaluating renal f unction and nonobstructing ureteral calculi, noncontrasted CT is a sen sitive imaging modality for the detection of urinary tract calculi and obstruction. The majority of our patients required no further imaging to determine the need for urological intervention. At our institution spiral CT has become the standard method to evaluate patients with ac ute flank pain leading to more rapid turnover in the emergency departm ent at similar or even reduced cost to conventional excretory urograph y.