Low-cost soft-copy display accuracy in the detection of pulmonary nodules by single-exposure dual-energy subtraction: comparison with hard-copy viewing.

This study endeavored to clarify the usefulness of single-exposure dual-energy subtraction computed radiography (CR) of the chest and the ability of soft-copy images to detect low-contrast simulated pulmonary nodules. Conventional and bone-subtracted CR images of 25 chest phantom image sets with a low-contrast nylon nodule and 25 without a nodule were interpreted by 12 observers (6 radiologists, 6 chest physicians) who rated each on a continuous confidence scale and marked the position of the nodule if one was present. Hard-copy images were 7 x 7-inch laser-printed CR films, and soft-copy images were displayed on a 21-inch noninterlaced color CRT monitor with an optimized dynamic range. Soft-copy images were adjusted to the same size as hard-copy images and were viewed under darkened illumination in the reading room. No significant differences were found between hard- and soft-copy images. In conclusion, the soft-copy images were found to be useful in detecting low-contrast simulated pulmonary nodules.

Comparison between computer-aided diagnosis and radiologists: assessment of pulmonary blood flow on chest radiographs.

To evaluate the performance of a computer-aided diagnosis (CAD) scheme for estimating increased pulmonary blood flow on chest radiographs, we compared computerized assessment with findings by radiologists. Our CAD scheme extracts selectively linear opacities corresponding to vessels in regions of interest (ROIs) in the right upper and lower lung zones on digitized chest radiographs, and then calculates a radiographic index as a physical measure that reflects the area of the extracted opacities in selected ROIs. As a measure of increased pulmonary blood flow, the upper/lower radiographic index ratio was calculated for each patient. Seven radiologists estimated the degree of increased pulmonary blood flow for the same images of ROI sets presented on a cathode-ray tube monitor in a randomized order. Between the normal-pulmonary capillary wedge pressure (PCWP) group and increased-PCWP groups, there was no significant difference in performance between CAD and radiologists (p = 0.105). However, when the normal and mild PCWP groups were compared, the performance of CAD was superior to that of radiologists (p = 0.001). This study indicates that our CAD scheme is promising for quantitative estimation of increased pulmonary blood flow, especially in mild cases.

Significant reduction of medical costs by differentiation therapy with all-trans retinoic acid during remission induction of newly diagnosed patients with acute promyelocytic leukemia. The Japan Adult Leukemia Study Group.

BACKGROUND: Differentiation therapy with all-trans retinoic acid (RA) induces more than 80% complete remission with the least complications in patients with acute promyelocytic leukemia (APL). The authors studied the cost-benefit of this new treatment modality compared with conventional chemotherapy in newly diagnosed patients with APL. METHODS: Costs were calculated retrospectively through the monthly bills of each patient to national health insurance and were compared between 36 patients treated with conventional chemotherapy in the AML-87 or AML-89 studies and 40 patients treated with all-trans RA alone or with all-trans RA plus low dose chemotherapy in the AML-92 study of the Japan Adult Leukemia Study Group who were treated at 22 university and cancer hospitals in Japan. RESULTS: Average medical costs except for antileukemic drugs during 2 months after admission were 4,164,026 yen (approximately US$46,300) in the chemotherapy group and 2,906,825 yen (approximately US$32,300) in the all-trans RA group (P < 0.0001). The difference resulted mainly from the costs of antibiotics and of platelet and erythrocyte transfusions. Average costs of antibiotics were 650,494 yen (approximately US$7,200) and 349,138 yen (approximately US$3,900), respectively (P < 0.0002), and those of platelet and erythrocyte transfusions were 1,016,190 yen (approximately US$11,300) and 633,444 yen (approximately US$7,000), respectively (P < 0.0020). CONCLUSION: During the remission induction therapy of newly diagnosed APL, all-trans RA significantly reduced medical costs. all-trans RA should be incorporated into the front-line therapy of patients with APL for medical and economic reasons.

Pleural invasion by peripheral bronchogenic carcinoma: assessment with three-dimensional helical CT.

PURPOSE: To evaluate the potential role of three-dimensional (3D) computed tomography (CT) in assessment of pleural invasion by peripheral bronchogenic carcinoma. MATERIALS AND METHODS: Twenty-four-second helical CT scans were obtained during a single breath hold in 42 consecutive patients with peripheral bronchogenic carcinoma. Conventional two-dimensional (2D) images and 3D reconstruction images were reviewed independently by three blinded observers, who reached a decision by consensus. All patients underwent surgical resection of the tumor, and CT findings were correlated with the findings in pathologic specimens. RESULTS: Twelve patients had visceral pleural invasion, five had parietal pleural invasion, and 25 had no evidence of pleural invasion. Visceral pleural invasion was identified on 2D CT images in two patients and on 3D reconstructions in 11. Parietal pleural invasion was identified on 2D CT images in two patients and on 3D reconstructions in three. CONCLUSION: 3D reconstruction imaging is superior to conventional 2D CT in assessment of pleural invasion by peripheral bronchogenic carcinoma.

Significance of the enhancement of GABA receptor binding with low affinity in the assessment of central effects of benzodiazepine derivatives: Analysis using a 1H-1,2,4-triazolyl benzophenone derivative (450191-S).

The central actions of 1-(2-o-chlorobenzoyl-4-chlorophenyl)-5-glycylaminomethyl-3-dimethylcarbamoyl-1H-1,2,4-triazole hydrochloride dihydrate (450191-S), a potent sleep-inducing and anxiolytic drug, were re-evaluated in terms of the affinity for benzodiazepine (BZP) receptor and the activation of ?-aminobutyric acid (GABA) receptor binding. The 450191-S showed only very low capacity to displace the bindings of [(3)H]diazepam, [(3)H]?-carboline-3-carboxylate-ethylester, [(3)H]Rol5-1788, [(3)H]Ro5-4864 and [(3)H]naloxone to cerebral synaptic membranes. Similarly, this drug had a weak and undistinguishable affinity to both BZPtype 1 and 2 receptors determined under the presence of CL 218,872. On the other hand, 450191-S as well as its active metabolites (M-1, M-2, M-A, M-3 and M-4) showed a remarkable activating effect on the GABA receptor binding with low affinity in cerebral synaptic membranes. This enhancement of the low affinity GABA receptor binding was found to be due to the increase of affinity (K(d)) but not to the change in B(max). Furthermore, it has been found that the observed accentuation of low affinity GABA receptor binding is well-correlated with the potency of the central actions of 450191-S such as potentiation of the hypnotic action of barbiturates and muscle relaxation. These results suggest that the central actions of 450191-S may be due to, at least in part, the activation of central GABA receptor binding with low affinity. The present results also suggest that the activation of low affinity GABA receptor binding may be a better criterion than the affinity of BZP receptor for elucidating the central action of a certain type of BZP derivatives.