Comparison of diagnostic performance between 1 millisievert CT enterography and half-standard dose CT enterography for evaluating active inflammation in patients with Crohn's disease.

PURPOSE: To compare the diagnostic performance of CT enterography (CTE) images obtained at 1 millisievert (mSv) and reconstructed with filtered back projection (FBP) and adaptive statistical iterative reconstruction (ASIR) with those of half-dose CTE images for the evaluation of active inflammation in patients with Crohn's disease. METHODS: Forty-six consecutive patients (mean age 29 years; range 15-59 years) with Crohn's disease underwent CTE which comprised a standard-dose scan at the enteric phase (45 s), a half-dose scan with ASIR at the portal venous phase (70 s), and 1 mSv scans with FBP and ASIR at the delayed phase (90 s) under a fixed 120 kVp and variable mAs. Two blinded readers independently recorded confidence scores for active inflammation in the ileum and terminal ileum, respectively. The diagnostic performance of each image set was compared by pairwise comparison of receiver operating characteristic curves. The established image findings on standard-dose scan and ileocolonoscopy served as the reference standard. RESULTS: A total of 92 bowel segments were analyzed. For reader 1, the diagnostic performance was increased from 1 mSv CT with FBP and 1 mSv CT with ASIR to half-dose scan with ASIR (AUC, 0.759, 0.794, and 0.845; P = 0.1429, P = 0.0107, respectively). For reader 2, there was no significant difference among the three image sets (AUC, 0.848, 0.865, and 0.845; P > 0.05, respectively). CONCLUSIONS: The diagnostic performance of 1 mSv CTE may be comparable to that of half-dose CTE.

Incidentally detected breast lesions on chest CT with US correlation: a pictorial essay.

With the increasing use of computed tomography (CT), incidental breast lesions are detected more frequently. When interpreting chest CT findings, it is important for radiologists to carefully review the breast to recognize any abnormal findings that could affect patient management. The purpose of this study is to discuss incidental breast lesions on chest CT with ultrasonography correlation that may be encountered in routine clinical practice.

Apparent diffusion coefficient for discriminating metastatic from non-metastatic lymph nodes in primary rectal cancer.

OBJECTIVE: To investigate whether the apparent diffusion coefficient (ADC) could be used to discriminate metastatic from non-metastatic lymph nodes (LNs) in patients with primary rectal cancer. METHODS: This study investigated 34 patients (male: 12, female: 22, mean: 62.7, range: 37-82) who underwent 1.5-T MRI with diffusion-weighted imaging (DWI) and subsequent surgical resection. A blinded radiologist measured the ADC value in each regional LN after referring to the T2-weighted images and DWI. The t-test was used to compare the mean ADC values of the metastatic and non-metastatic LNs. A ROC analysis was performed to calculate the diagnostic performance and obtain the optimal cut-off. The histopathological results were used as the reference standard. RESULTS: 114 LNs (46 metastatic and 68 non-metastatic) were matched and analyzed. The mean ADC of the metastatic LNs was significantly lower than that of the non-metastatic LNs (0.9 ± 0.15 × 10(-3) mm(2)/s; 1.1 ± 0.22 × 10(-3) mm(2)/s, P<0.0001). The area under the ROC curve was 0.734 (95% confidence interval, 0.644-0.812). When an ADC value of 1.0 × 10(-3) mm(2)/s was used as the cut-off, a maximum accuracy of 72% was calculated (sensitivity, 78%; specificity, 67%). CONCLUSIONS: Although ADC could be used to discriminate metastatic from non-metastatic LNs, the diagnostic accuracy is approximately 70%.