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The aim of this study was to evaluate the decreasing of cardiac motion artifact and whether the extent of ground-glass attenuation of idiopathic pulmonary fibrosis (IPF) was accurately assessed by electrocardiography (ECG)-triggered high-resolution computed tomography (HRCT) by 0.5-s/rotation multidetector-row CT (MDCT).ECG-triggered HRCT were scanned at the end-diastolic phase by a MDCT scanner with the following scan parameters; axial four-slice mode, 0.5 mm collimation, 0.5-s/rotation, 120 kVp, 200 mA/rotation, high-frequency algorithm, and half reconstruction. In 42 patients with IPF, both conventional HRCT (ECG gating(-), full reconstruction) and ECG-triggered HRCT were performed at the same levels (10-mm intervals) with the above scan parameters. The correlation between percent diffusion of carbon monoxide of the lung (%DLCO) and the mean extent of ground-glass attenuation on both conventional HRCT and ECG-triggered HRCT was evaluated with the Spearman rank correlation coefficient test.The correlation between %DLCO and the mean extent of ground-glass attenuation on ECG-triggered HRCT (observer A: r = -0.790, P0.0001; observer B: r = -0.710, P0.0001) was superior to that on conventional HRCT (observer A: r = -0.395, P0.05; observer B: r = -0.577, P = 0.002) for both observers.ECG-triggered HRCT by 0.5 s/rotation MDCT can reduce the cardiac motion artifact and is useful for evaluating the extent of ground-glass attenuation of IPF.

To evaluate the patency of coronary artery bypass grafting (CABG) with multidetector-row computed tomography (MDCT) in Japanese patients, who have narrower coronary arteries than Caucasians.Nineteen patients (12 men and 7 women, mean age: 63 +/- 12 years) with 33 coronary bypass grafts were examined with three-dimensional volume rendering (3D-VR) and curved multiplanar reconstruction (MPR) of MDCT. All grafts were compared with those obtained with selective graft angiography.For the 19 patients with 33 grafts, the overall sensitivity and specificity, compared with those for selective bypass angiography, were 96.7% and 100%, respectively.The patency of CABG in Japanese patients can be effectively evaluated with 3D-VR and curved MPR of MDCT.

To clarify the appropriate voxel dimensions required for pathologic evaluation of areas with ground-glass opacity on lung high-resolution computed tomography (HRCT).Synchrotron radiation CT (SRCT) images of autopsied lung speci-mens (n=25) that showed ground-glass opacity on HRCT were reconstructed with 12 different voxel dimensions ranging from 0.006 to 0.6 mm. The specimens were micromorphologically categorized into one of three pathologic groups: alveolar, interstitial, and mixed abnormalities. Each SRCT image was independently diagnosed as one of three pathologic groups by six chest radiologists. The diagnostic accuracy required to estimate the appropriate voxel dimensions was compared among different voxel dimensions by means of the Tukey test.Diagnostic accuracy with voxel dimensions less than or equal to 0.06 mm was significantly higher than that with voxel dimensions of 0.18 mm or more (p0.01). There was, however, no significance of difference in diagnostic accuracy with voxel dimensions of less than or equal to 0.06 mm. In addition, no significant difference in diagnostic accuracy was found with voxel dimensions of 0.18 mm or more.The appropriate voxel dimensions are approximately 0.06 mm for pathologic differentiation of areas with ground-glass opacity on HRCT.

Pulmonary atresia (PA) and ventricular septal defect (VSD) are usually associated with major aortopulmonary collateral arteries (MAPCAs). Preoperative evaluation of MAPCAs is essential for effective planning of unifocalization. Multidetector-row computed tomography (MDCT) with three-dimensional volume rendering (3D-VR) demonstrates MAPCAs as well as conventional angiography. We report two cases of PA and VSD associated with MAPCAs examined pre- and postoperatively by means of angiography and MDCT with the 3D-VR technique. MDCT with the 3D-VR technique had the potential to elucidate all MAPCAs demonstrated by invasive angiography. This technique is useful with preoperative conventional angiography as a standard examination for the planning of staged surgery.

The purpose of this study was to evaluate the usefulness of the coronal multiplanar reconstruction (MPR) view in comparison with transverse helical thin-section CT for both the determination of malignant or benign lesions and the differential diagnosis of solitary pulmonary nodules.Sixty-eight cases of pathologically proved solitary pulmonary nodule less than 3 cm in diameter were enrolled in this study. For the routine study, transverse helical thin-section CT (1.25 mm collimation, FOV 20 cm) covering the areas with solitary pulmonary nodules as well as whole lung helical thin-section CT (2.5 mm collimation, 1.25 mm reconstruction interval, FOV 34.5 cm, pitch 6:1, high-spatial frequency algorithm) were scanned with a multidetector-row CT (MDCT) scanner. From the whole lung thin-section CT data, coronal MPR views (2.5 mm slice thickness) were reconstructed on a workstation. ROC analysis was used for an observer performance study, in which three observers indicated their confidence level for the determination of malignant or benign lesion for the nodules by means of transverse thin-section CT and coronal MPR. In addition, the observers recorded appropriate disease entities as the final diagnosis of each case. Accuracies of the final diagnosis based on the two sets of images were compared with McNemer' s test.In terms of the determination of malignant or benign lesion, there was no significant difference between the two sets of images (coronal MPR and transverse thin-section CT; mean Az=0.853 and 0.854, respectively). In addition, accuracy of the final diagnosis based on coronal MPR views (74%) was almost equal to that based on transverse thin-section CT (71%) (p=0.3).The diagnostic efficacy of the coronal MPR view is comparable to that of transverse thin-section CT for the evaluation of solitary pulmonary nodules.

The purpose of this study was to construct a system that calculates mean glandular dose (MGD) in mammography in real-time on the RIS network.Measurement of the half-value layer (HVL) and exposure dose were measured according to the Japanese mammographic quality control manual. A parallel plate chamber (10X5-6M; soft X-rays only) was used for measurement. Exposure dose was measured from 26 to 32 kV.Effective energy (Eeff [keV]) could be determined from tube voltage (V [kV] ) using the measure of the HVL according to the following equations: for the Mo/Mo combination, Eeff = 0.1325V + 11.80; for the Mo/Rh combination, Eeff = 0.1435V + 12.20; for the Rh/Rh combination, Eeff = 0.1724V + 11.29. Exposure output (XmAs [mR/mAs]), which can be determined from dosimetry per 1 mAs, becomes the following equation if effective energy is expressed as a variable: for the Mo/Mo combination, XmAs = 2.1329 Eeff2 - 57.784 Eeff + 392.71; for the Mo/Rh combination, XmAs = 1.1919 Eeff2 - 31.924 Eeff + 212.23; and for the Rh/Rh combination, XmAs = 2.6929 Eeff2 - 82.831 Eeff + 643.54. The MGD conversion factor (DgN [mGy/mR]) can be determined from effective energy using the ACR protocol according to the following equation: for the Mo/Mo combination, DgN = (0.3962 Eeff- 4.3178) 10(-3); for the Mo/Rh combination, DgN = (0.3495 Eeff - 3.5479) x 10(-3); and for the Rh/Rh combination, DgN = (0.4498 Eeff - 5.0448) x 10(-3). However, in these cases, compression breast thickness (CBT) was 4.2 cm, and the ratio of adipose and glandular tissue was 50/50.MGD can be determined using mAs obtained from mammography, exposure output (XmAs), MGD conversion factor (DgN), and source-skin distance compensation factor (SSDcf) according to the following equation: MGD [mGy] = mAs x XmAs [mR/mAs] x DgN [mGy/mR] x SSDcf where SSDcf = (64/(64 - CBT [cm]))2.

To assess the detection and size of mediastinal and hilar lymph nodes by multiplanar reconstruction (MPR) view from isotropic voxel data sets obtained with multidetector-row computed tomography (MDCT).Thin-section CT of 27 patients with mediastinal or hilar lymph node swelling was obtained with a 25.6-cm FOV, 512 x 512 matrix, and two protocols: A) 0.5-mm collimation, 0.3-mm interval, and B) 2-mm collimation, 1-mm interval. MPR views with a 0.5-mm slice thickness were obtained from these two data sets. Postcontrast axial CT used 5-mm collimation (set C). Two observers evaluated the presence and cranio-caudal length of swollen lymph nodes. Two other board-certified chest radiologists evaluated all three sets and established a gold standard by consensus.The accuracy of detection was 76%, 73%, and 68% for sets A, B, and C, respectively. There was a significant difference between sets A and C (McNemar's test: p0.05) but not between sets A and B or B and C (p0.05). The cranio-caudal length of lymph nodes was significantly correlated with the gold standard only in set A (Pearson's correlation coefficient: r=0.53, p0.05).Non-contrast enhanced coronal MPR views constructed from isotropic voxel data sets may be substituted for axial enhanced CT for the evaluation of mediastinal and hilar lymph nodes.