The diagnostic performance of our low-dose CT protocol for renal colic was excellent for all patients, and image quality and diagnostic confidence were significantly better for patients with a BMI≥25. However, our protocol also required exposure to a greater dose of radiation for these overweight and obese patients.

Objective: To evaluate an alternative method to reduce the acquisition coverage of urinary tract CT. Methods: This retrospective study included 365 abdominopelvic CT studies. Three radiographers simulated shortened acquisition coverages using three methods to determine the upper limit of the acquisition: Method 1 used the renal contours; Method 2 used the inferior margin of the 10th thoracic vertebra; and Method 3 used the point of intersection of the left diaphragmatic dome and the anterior margin of the vertebral bodies. Reductions in acquisition coverage and number of CT scans with a portion of the kidney excluded from the simulated reduced acquisition were compared between the three methods.Results: The mean 6 standard deviation reduction of acquisition coverage for the three readers with Methods 1, 2 and 3 were 20.5 6 4.8, 15.1 6 6.5 and 18.2 6 5.3%, respectively. Compared with Method 2, Method 3 allowed a mean scan length reduction of 3.6%. The proportions of CT scans with a portion of the kidney excluded from the simulated reduced acquisition with Methods 1, 2 and 3 and averaged over the three readers were 6.7, 0.7 and 1.4%, respectively, with no significant difference between Methods 2 and 3. Interreader and intrareader agreements were excellent with all methods, but interclass correlation coefficients were higher with Method 3. Conclusion: The method using the renal contours should not be used owing to its high proportion of kidneys with a portion excluded from the acquisition. Using the intersection of the left diaphragmatic dome and the anterior margin of the vertebral bodies for proximal landmark for urinary tract CT represents a new alternative method with a better reduction of scan length compared with the method using the inferior margin of T10 and with no significant increase in the number of kidneys with a portion excluded from the reduced acquisition. Advances in knowledge: A new method using the point of intersection of the left diaphragmatic dome and the anterior border of the vertebral bodies on the lateral scout radiograph is introduced to reduce the z-axis coverage of urinary tract CT scans.

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Computed tomography (CT) has become the reference technique in medical imaging for renal colic, to diagnose, plan treatment and explore differential diagnosis. Its main limitation is the radiation dose, especially as urinary stone disease tends to relapse and mainly affects young people. It is therefore essential to reduce the CT radiation dose when renal colic is suspected. The goal of this review was twofold. First, we wanted to show how to use low-dose CT in patients with suspected renal colic in current clinical practice. Second, we wished to discuss the different ways of reducing CT radiation dose by considering both behavioral and technological factors. Among the behavioral factors, limiting the scan coverage area is a straightforward and effective way to reduce the dose. Improvement of technological factors relies mainly on using automatic tube current modulation, lowering the tube voltage and current as well using iterative reconstruction.

Gastric wall fatty infiltration was significantly more frequent in men older than 45 years and patients with a body mass index greater than 25. It may represent a normal finding, but its relation to other pathologic conditions related to obesity remains to be explored.