Thoracic manifestations of adult T-cell leukemia/lymphoma on chest CT: difference between clinical subtypes.

PURPOSE: We aimed to evaluate thoracic computed tomography (CT) findings in adult T-cell leukemia/lymphoma (ATL) and their differences among clinical subtypes. METHODS: Thoracic CT scans of 49 ATL patients were retrospectively reviewed. On CT scans, the presence of lung parenchymal abnormalities (10 patterns), enlarged lymph nodes, pleural and pericardial effusions, and subcutaneous nodules was evaluated by two radiologists in cooperation. According to the Shimoyama criteria, the patients were divided into aggressive ATL group (n=28, acute and lymphoma types) and indolent ATL group (n=21, chronic and smoldering types). Differences in the prevalence of the CT findings between the two groups were examined. In the indolent ATL group, CT scans of 10 patients who eventually underwent transformation to aggressive ATL were also evaluated. RESULTS: In aggressive ATL, enlarged lymph nodes (68%) was the most frequently observed finding. Several patterns of lung abnormalities were observed, such as ground-glass attenuation (36%), bronchial wall thickening (32%), nodules (29%), and centrilobular opacities (29%). In indolent ATL, enlarged lymph nodules (24%) and bronchiectasis (24%) were relatively frequently detected. Overall, the incidence of abnormal findings was higher in aggressive than in indolent ATL, except for bronchiectasis. Patients with transformation to aggressive ATL frequently demonstrated enlarged lymph nodes (80%). CONCLUSION: On thoracic CT, enlarged lymph nodes and various lung and airway abnormalities, such as ground-glass attenuation and bronchial wall thickening, were observed in ATL patients, particularly those with aggressive ATL. Bronchiectasis was similarly found in patients with indolent ATL and aggressive ATL.

Adaptive Iterative Dose Reduction Using Three Dimensional Processing (AIDR3D) improves chest CT image quality and reduces radiation exposure.

OBJECTIVE: To assess the advantages of Adaptive Iterative Dose Reduction using Three Dimensional Processing (AIDR3D) for image quality improvement and dose reduction for chest computed tomography (CT). METHODS: Institutional Review Boards approved this study and informed consent was obtained. Eighty-eight subjects underwent chest CT at five institutions using identical scanners and protocols. During a single visit, each subject was scanned using different tube currents: 240, 120, and 60 mA. Scan data were converted to images using AIDR3D and a conventional reconstruction mode (without AIDR3D). Using a 5-point scale from 1 (non-diagnostic) to 5 (excellent), three blinded observers independently evaluated image quality for three lung zones, four patterns of lung disease (nodule/mass, emphysema, bronchiolitis, and diffuse lung disease), and three mediastinal measurements (small structure visibility, streak artifacts, and shoulder artifacts). Differences in these scores were assessed by Scheffe's test. RESULTS: At each tube current, scans using AIDR3D had higher scores than those without AIDR3D, which were significant for lung zones (p<0.0001) and all mediastinal measurements (p<0.01). For lung diseases, significant improvements with AIDR3D were frequently observed at 120 and 60 mA. Scans with AIDR3D at 120 mA had significantly higher scores than those without AIDR3D at 240 mA for lung zones and mediastinal streak artifacts (p<0.0001), and slightly higher or equal scores for all other measurements. Scans with AIDR3D at 60 mA were also judged superior or equivalent to those without AIDR3D at 120 mA. CONCLUSION: For chest CT, AIDR3D provides better image quality and can reduce radiation exposure by 50%.

Kurtosis and skewness assessments of solid lung nodule density histograms: differentiating malignant from benign nodules on CT.

PURPOSE: The purpose of our study was to assess pulmonary nodule characteristics using density histogram kurtosis and skewness and to distinguish malignant from benign nodules. MATERIALS AND METHODS: Ninety-three lung nodules on CT were analyzed, including 72 malignant and 21 benign nodules. They were completely solid or solid with limited ground-glass opacity. Based on their CT characteristics, nodules were categorized into type A, homogeneous nodules with uniform internal structures and clear margins, and type B, inhomogeneous nodules with heterogeneous structures or uneven margins. Kurtosis and skewness were calculated from density histograms to compare type A and B nodules and malignant and benign nodules. Receiver-operating characteristic (ROC) curves were generated to assess kurtosis and skewness for discriminating between different nodule types. RESULTS: Type A nodules (n = 35) had greater kurtosis and reduced skewness (p < 0.001) compared to type B nodules (n = 58). Malignant tumor kurtosis was greater than that of benign nodules (type A, p < 0.05; type B, p = 0.001). Type B malignant tumors had reduced skewness compared to benign nodules (p < 0.05). ROC curves provided relatively high values for the area under the curve (0.71-0.83). CONCLUSION: Kurtosis and skewness assessments of density histograms may be useful for differentiating malignant from benign nodules.

320-Row wide volume CT significantly reduces density heterogeneity observed in the descending aorta: comparisons with 64-row helical CT.

The aim of this study was to compare density heterogeneity on wide volume (WV) scans with that on helical CT scans. 22 subjects underwent chest CT using 320-WV and 64-helical modes. Density heterogeneity of the descending aorta was evaluated quantitatively and qualitatively. At qualitative assessment, the heterogeneity was judged to be smaller on WV scans than on helical scans (p<0.0001). Mean changes in aortic density between two contiguous slices were 1.64 HU (3.40%) on WV scans and 2.29 HU (5.19%) on helical scans (p<0.0001). CT density of thoracic organs is more homogeneous and reliable on WV scans than on helical scans.

Diffusion-weighted MRI and PSA correlations in patients with prostate cancer treated with radiation and hormonal therapy.

AIM: To investigate the correlation between signal intensity (SI) on diffusion-weighted imaging (DWI) and the levels of prostate-specific antigen (PSA) in patients with prostate cancer treated with radiation and hormonal therapy. PATIENTS AND METHODS: Forty-four patients with prostate cancer treated with hormonal therapy and radiation therapy were evaluated. Areas with high SI on DWI were detected and the apparent diffusion co-efficient (ADC) values were measured. The ADC values and PSA levels were compared between patients with high-DWI SI and patients with a normal DWI signal. RESULTS: Fourteen patients had high SI on DWI. The mean ADC value in these cancerous lesions was lower than in non-cancerous tissues. The mean PSA level in patients with high-DWI SI was significantly higher than in patients with a normal signal. CONCLUSION: The present results suggest that SI on DWI appears to correlate with PSA levels in patients with prostate cancer treated with radiation and hormonal therapy.