Quantification of Urinary Stone Volume: Attenuation Threshold–based CT Method—A Technical Note

Abstract

An attenuation threshold-based CT method can be used to quantify urinary stone volume even at low radiation doses. The most accurate and precise method utilizes variable attenuation derived from the attenuation of each stone and thin sections.

Association Between Left and Right Atrial Remodeling With Atrial Fibrillation Recurrence After Pulmonary Vein Catheter Ablation in Patients With Paroxysmal Atrial Fibrillation

“…22 Helms et al 12 demonstrated in a 12-month follow-up study of the both paroxysmal and permanent AF patients, using 3-dimensional MDCT that the sensitivity of large LA volumes Ͼ135 mL for predicting the recurrence of AF was 36%, and the specificity of such volumes was 96%. In the present study, the higher diagnostic accuracy of each atrial enlargement for predicting AF recurrence was obtained by quantitative 3-dimensional measurements in combination with a computer-and navigation-aided technique (OsiriX software), [17][18][19] and the value of combined atrial volumes had the highest diagnostic accuracy. The combined LA and RA enlargements may better express more remarkable, overall structural remodeling than examination of individual atrial remodeling.…”

“…OsiriX software allows the quantitative measurement of volume from 3-dimensional MDCT data. [17][18][19] Each short-axis 0.7-mm interval CT image was examined, and the region of interest was defined on the LA and RA areas ( Figure 2). Thus, RA and LA volumes were quantitatively calculated from 3-dimensional images, using OsiriX software.…”

Urinary stone size estimation: a new segmentation algorithm-based CT method

“…Eleven readers were included, four radiology residents with 1, 5, 5 and 5 years' experience and seven radiologists with 6,8,14,19, 20, 28 and 31 years' experience respectively.…”

“…A previous in vitro study using OsiriX software (OsiriX Foundation, Geneva, Switzerland) demonstrated that a semi-independent segmentation algorithm with a variable segmentation threshold had better results on calculus volume than a fixed threshold [6]. The image processing steps in the algorithm, apart from the segmentation threshold, was however not discussed in the article.…”

Ultrasonography versus computed tomography for initial investigation of suspected nephrolithiasis

“…1 Abdominal computed tomography (CT) has become the most common first-line imaging modality for investigating nephrolithiasis. 4,5 CT is attractive due to its high sensitivity for stone detection, ability to assess stone size, 6,7 and utility in making alternate diagnoses. The main limitations of CT include exposure to ionizing radiation, a high rate of incidental findings, increased cost per investigation, and its lack of demonstrated correlation with improved patient outcomes.…”