Assessment of Focal Liver Lesions with 4-Phase Dynamic FLASH MR Imaging: Usefulness of Early Image Acquisitionfor Characterization of Arterial Phase

PURPOSE: To document the usefulness of early image acquisition using the contrast-enhanced dynacic MR imagingfor characterization of various focal hepatic lesions during the arterial phase. MATERIALS AND METHODS:Seventy-nine patients with 145 focal liver lesions (71 hemangiomas, 59 hepatocellular carcinomas and 15metastases) underwent breathhold dynamic MR imaging using a fast low-angle shot sequence. After obtainingunenhanced T1-weighted images, four phase MR images were obtained 10, 35, 60 and 300 seconds after starting theinjection. Patterns of contrast enhancement were analyzed for each lesion, with an emphasis on first phase images. RESULTS: Forty-two of the 59 HCCs (71%) showed prominent contrast enhancement during the first phase. HCCssmaller than 2cm in diameter showed a more homogeneous enhancement pattern than those which measured 2cm ormore(24/25 vs 12/17;P<.05). Hemangiomas showed a globular enhancement pattern during the same phase in 51 of 71cases (72%), a finding which was more apparent in those whose diameter was 2cm or more(35/54 vs 16/17, p<.05).During the first phase of imaging, 12 of the 15 metastases showed peripheral enhancement of their thick rim. CONCLUSION: The use of early image acquisition on dynamic MR sequences is helpful in character-izing lesionsaccrding to their pattern of contrast enhancement.

Risk Factors of Pneumothorax in Percutaneous Fine Needle Aspiration Biopsy of the Lung

PURPOSE: Percutaneous fine needle aspiration biopsy is known to be a useful diagnostic method for the diagnosis of various pulmonary diseases. Its diagnostic yield is high, and it is safe, but complications such as pneumothorax can occasionally occur. We reviewed the complications arising after needle aspiration biopsy and analyzed the risk factors of pneumothorax. MATERIALS AND METHODS: The medical records and radiographic studies of 157 patients with various pulmonary diseases who underwent needle aspiration biopsy of the lung between 1990 and 1996 were retrospectively reviewed. The clinical features, treatment, and courses of complications were reviewed, and risk factors of pneumothorax such as depth and size of lesion, diameter of needle, number of punctures, and obstructive pulmonary abnormalities were analyzed. RESULTS: Complications occurred in 40 of 157 cases (25.5%), namely pneumothorax in 26 (16.6%), hemoptysis in 11 (7%), hemothorax in two (1.3%), and recurrence of malignancy at the site of aspiration in one (0.6%). When the patients were divided into three groups according to depth of lesion, there were significant difference in the incidence of pneumothorax ; the results were as follows : less than 2cm, 12.9% ; between 2 and 4cm, 24.1% ; and larger than 4cm, 57.1% (p<0.05). In pulmonary function testing, FVC (forced vital capacity) of patients with pneumothorax was less than that of patients without (2.6+/-0.9L vs 3.1+/-0.8L, p<0.05), but FEV1 (forced expiratory volume in 1 second), FEV 1% (percentage of predicted FEV1), FEV1/FVC,and FVC%(percentage of predicted FVC) were not different between the two groups. The incidence of pneumothorax in patients with pleura-attached lesion (9%) was lower than that of those with non-attached lesion (26%, p=0.01). The age of patients, size of lesion, diameter of the needle, guidance methods and number of aspirations showed no significant relationship with pneumothorax. CONCLUSION: In needle aspiration biopsy of the lung, depth of lesion and passage of a needle through aerated lung are significant risk factors of pneumothorax.

Detection of Diffuse calcification in a Pulmonary Nodule: Diagnostic Accuracy of Chest Radiolograph and correlation with CT

PURPOSE: To evaluate the diagnostic accuracy of chest x-ray interpretation of diffuse calcification of pulmonary nodules. MATERIALS AND METHODS: On plain chest radiograph and CT, 152 pulmonary nodules with diffuse calcification in 98 patients were selected. The nodules were of various diameters : 44 were of 0.5 - 1cm (Group1), 58 were of 1 - 2cm (Group 2), and 50 were of 2 - 3cm (Group 3). On plain chest radiograph, diffuse calcification was considered to be present when the density of pulmonary nodules of 0.5 - 1cm and 1 - 2cm indiameter was greater than that of the overlapping area of the second and fifth ribs. The density of nodules 2-3cmin diameter was compared with that of the mid-claviclar cortex; calcification was considered to be present when the density of the former was greater than that of the latter. Diffuse calcification of a pulmonary nodule on CT image was considered to be present when more than 10% of the area of the nodule showed a higher attenuation than the surrounding rib cortex. RESULTS: The overall diagnostic accuracy of chest radiographs in the detection of diffuse calcification was as follows : sensitivity 77.6%, specifity 89%, PPV (positive predictive value) 82.3%, NPV(negative predictive value) 86.9%. In group 1, sensivity was 96%, specifity 89.5%, PPV 91.6%, and NPV 94.9%. In group 2 nodules, sensitivity was 77.8%, specifity 91%, PPV 89%, and NPV 81.4%. In group 3, sensitivity was 56%,specifity 88% PPV 56% and NPV 83.9%. CONCLUSION: Chest radiographs showed relatively high accuracy in the diagnosis of diffuse calcificatio of pulmonary nodules, particulary when the nodule was less than 2cm in diameter. As the nodule increased in diameter, diagnostic accuracy declined.

Neuroblastoma: Computed Tomographic Findings

PURPOSE: To evaluate the characteristic CT findings of neuroblastoma, we studied neurobalstomas. METHODS AND MATERIALS: We analysed CT findings of available 25 cases among pathologically proved 51 neurobalstomas from Jan. 1983 to Sept. 1990. RESULTS: The most frequent site of origin is adrenl gland (40%) and the second is retroperitoneum (32%) and the third ismediastinum (16%). Characteristic CT findings are as follows:Calcifications within the tumor is detected in 86% of abdominal neuroblastomas and 50% of mediastinal origin. Hemorrhagic and necrotic changes within the tumor is noted at 86% in the tumor of abdominal origin and 25% in mediastinal neuroblastomas. Contrast enhanced study showed frequently septated enhanced appearance with/without solid contrast enhancement. Encasements of major great vessels such as aorta and IVC with/without displacement by metastatic lymphnodes or tumor are frequently seen in 90% of abdominal neuroblastomas. Multiple lymphadenopathy are detected in 95% of abdominal neurobalstomas and 25% of mediastinal neuroblastomas. The most common organ of contiguous direct invasion is kidney in 6 cases and the next one is liver but intraspinal canal invasion is also noted in 2 cases. CONCLUSION: We concluded that diagnosis of neuroblastoma would be easily obtained in masses of pediatric group from recognition of above characteristic findings.

CT findings of small cell bronchogenic carcinoma

No abstract available.