Chest radiographs obtained with shaped filters: evaluation by observer performance tests

The effectiveness of a shaped filter in improving nodule and infiltrate detection was measured by observer performance testing. Seven observers read 152 test radiographs of the chest obtained from human volunteers. Half the test radiographs had target images. Observer performance in detecting nodule or infiltrate images was compared with the shaped-filter system and with a conventional chest imaging system. The results were analyzed using receiver operating characteristic (ROC) techniques and indicate that the filter technique was not significantly different from the conventional technique in infiltrate depiction. Observer performance in detecting nodules was slightly worse on images obtained with the shaped-filter system.     

Quantitative US attenuation in normal liver and in patients with diffuse liver disease: importance of fat

Two methods are used to estimate ultrasound attenuation in liver. These were based on amplitude change and frequency change as a result of depth dependent attenuation. Evaluation of the two methods against a family of calibrated phantoms yielded correlation coefficients of 0.98 and 0.99, respectively. Liver attenuation in 26 control subjects was 0.50 and 0.52 dB/MHz/cm, respectively. Liver attenuation was estimated in 50 patients who later underwent liver biopsy. Comparison with quantitative histologic results showed that the presence of fat alone accounted for the increased attenuation associated with cirrhosis. Similar high attenuation values were found in patients with fatty infiltration. Fibrosis alone did not result in elevated liver attenuation. Cirrhotics without fatty infiltration had attenuation similar to that of the controls. Mechanisms of action are discussed.     

Calcification in pulmonary nodules: detection with dual-energy digital radiography

The authors undertook a clinical study to determine the accuracy of dual-energy digital radiography in revealing nodule calcification because calcification in a pulmonary nodule almost excludes the possibility of malignancy. Over a 6-month period, 61 patients with pulmonary nodules (less than or equal to 3 cm) or masses (greater than 3 cm) were examined on a prototype scanned projection unit using a dual-energy detector. In 49 of 61 patients, nodules were noncalcified, and in 12, they were calcified. In 57 patients, the benignancy or malignancy of nodules was established beyond reasonable doubt by pathologic confirmation in 38 and by strong inference in 19 (four patients with noncalcified solitary pulmonary nodules either refused further investigation or surgery or their follow-up was too short to permit exclusion of malignancy). Dual-energy radiography was found to be highly accurate in assessing the presence or absence of calcification in pulmonary nodules and thus in determining their benignancy or possible malignancy.     

Pseudoportal Doppler signal in the partially obstructed inferior vena cava

The Doppler spectrum of the normal inferior vena cava (IVC) shows a majority of flow toward the right atrium, with wide variations in flow velocity and direction owing to effects of the cardiac and respiratory cycles. Seventeen subjects underwent duplex sonography: nine children after liver transplantation, two children with right upper quadrant neuroblastoma, and six healthy control subjects. In six children the spectrum obtained from the IVC bore a strong resemblance to the unidirectional, low-velocity, continuous-flow pattern associated with the portal vein; these children included two children with biliary atresia and cirrhosis, two liver transplant recipients, and two children with IVC compression by neoplasm. In healthy children and adults, a pseudoportal Doppler signal in the IVC can be generated by subcostal right upper quadrant compression. The pseudoportal IVC appears to be a sign of partial IVC obstruction. Knowledge of this potential pitfall and meticulous morphologic imaging can help prevent mistaking the IVC for a patent portal vein.     

Long-range mapping of the Philadelphia chromosome by pulsed-field gel electrophoresis

The Philadelphia chromosome (Ph1) of chronic myelogenous leukemia (CML) contains sequences from chromosome 9, including the ABL protooncogene, that have been translocated to the breakpoint cluster region (bcr) of chromosome 22, giving rise to a bcr-ABL fusion gene, whose product has been implicated in the genesis of CML. Although chromosome 22 translocation breakpoints in CML virtually always occur within the 5.8- kilobase (kb) bcr, chromosome 9 breakpoints have been identified within the known limits of ABL in only a few instances. For a better understanding of the variability of the breakpoints on chromosome 9, we studied the CML cell line BV173. Using pulsed-field gel electrophoresis (PFGE), large-scale maps of the t(9;22) junctions were constructed. The chromosome 9 breakpoint was shown to have occurred within an ABL intron, 160 kb upstream of the v-abl homologous sequences, but still 35 kb downstream of the 5'-most ABL exon. bcr-ABL and ABL-bcr fusion genes were demonstrated on the Ph1 and the 9q+ chromosomes, respectively; both of these genes are expressed. These results suggest that the 9;22 translocation breakpoints in CML consistently occur within the limits of the large ABL gene. RNA splicing, sometimes of very large regions, appears to compensate for the variability in breakpoint location. These studies show that PFGE is a powerful new tool for the analysis of chromosomal translocations in human malignancies.     

介入化疗在宫颈癌近期疗效的观察

目的：探讨髂内动脉化疗或子宫动脉化疗栓塞在宫颈癌治疗中的意义。方法：给82例宫颈癌患者做髂内动脉化疗或子宫动脉化疗栓塞加放疗共97次，为观察组，另外选择与上述分期相近的81例为对照组。观察并评定各组疗效。结果：观察组CR23例，PR45例，SD9例，PD5例，有效率82．9％。其中11例介入治疗后手术。对照组，CR16例，PR38例，SD23例，PD4例，有效率66．6％。结论：髂内动脉化疗或子宫动脉化疗栓塞作为宫颈癌的辅助治疗行之有效，能缩小原发病灶，尽快缓解临床症状，与放疗结合，可提高治疗效果，具有较好的临床价值。