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Purpose: Evaluating the status of disease progression is critical for planning a therapeutic strategy for esophageal cancer. In this regard, F-18 fluorodeoxyglucose-labeled positron emission tomography (PET) is one of the most useful diagnostic modalities. However, there is room to improve its diagnostic performance, such as distinguishing lymph nodal metastases from false positives. In this study, we examined the diagnostic accuracy of fluorodeoxyglucose PET accompanied by computed tomography imaging (PET/CT) to detect regional lymph nodal metastasis from esophageal squamous cell carcinoma (ESCC)., Methods: A total of 102 patients diagnosed as ESCC were subjected to this study. These patients had a preoperative PET/CT examination to evaluate the existence of metastasis. The values of maximum standardized uptake value (SUVmax) in primary tumors and in metastasized lymph nodes were measured to analyze their relationship with various clinicopathologic characteristics including the status of tumor cell proliferation, which was assessed by immunohistochemistry for Ki-67., Results: The SUVmax of the primary tumor was positively correlated with tumor size and vessel invasion, and was positively related with the SUVmax of lymph nodal metastasis, especially in cases of poorly differentiated ESCC. The SUVmax of metastasized lymph nodes was higher in larger-sized metastasized lymph nodes, whereas the Ki-labeling index of lymph nodal metastasis was positively related with the SUVmax per unit area (SUVmax/mm). The diagnostic accuracy of PET/CT (87.3%) was higher than that of conventional CT scans (78.4%)., Conclusions: The improved diagnostic accuracy of PET/CT can be explained by its ability to detect actively progressive metastasis at an early phase regardless of size.

Purpose: The present study assessed the usefulness of CT for diagnosis of pulmonary emphysema (PE) using teleradiology., Methods: We reviewed 95 cases (56 men and 39 women, ranging in age from 18 to 89 years) who had undergone CT examination between June 2002 and January 2003. CT images were transmitted via ISDN by DICOM to our hospital, and displayed in 4-image and 1-image format for reading on an image viewer., Results: In 72 of the total 95 cases, both 1-image and 4-image displays were normal, and no PE was detected. Of the remaining 23 patients, PE was found in 22 on 4-image display and in all 23 on 1-image display. The same grade and subtype were observed on 4-image and 1-image displays in 19 cases. On the other hand, difference in diagnosis between the two types of display was obtained in four cases, in which mild low attenuation areas (LAAs) such as grade 1 or grade 2 centrilobular emphysema were found on the 1-image display but not seen on the 4-image display., Conclusions: The diagnosis of PE can be made by CT examination using teleradiology even in cases of mild lesions, when, for example, LAAs were found on the 1-image display but not seen on the other one. Therefore, teleradiology enables rapid diagnosis even in medical institutions where no expert chest radiologist is present.

Background: We examined the factors of delayed enhancement of hepatocellular carcinoma (HCC) on dynamic computed tomography (CT)., Methods: Dynamic CT and angiography were compared in 113 patients who had undergone transcatheter arterial chemoembolization or transcatheter arterial chemoinfusion and were suspected of developing new HCCs., Results: Eight of 113 patients had HCC nodules that enhanced gradually from the arterial phase to the portal venous phase on dynamic CT and were fed by extrahepatic arteries on angiography. The feeding artery was an omental branch of the splenic artery in one lesion, an omental branch of the gastroduodenal artery in five, and the intercostal artery in two., Conclusion: We believe that the recurrence of HCCs delayed enhancement on dynamic CT because the hepatic artery was hidden and long narrow extrahepatic collaterals fed the tumor.

We report on the usefulness of spiral computed tomography (CT) with 3-dimensional (3D) reconstruction in the diagnosis of tracheobronchial abnormalities based on three cases of children with congenital tracheobronchial strictures. Images were reconstructed using a curved planar reformat and shaded surface display. The images obtained from our three cases of tracheal stenosis, subglottic stenosis and tracheobronchial strictures were extremely clear. Spiral CT with 3D reconstruction provides excellent anatomic delineation of the tracheobronchial airway, and is safe and less invasive than tracheobronchography.

Two cases of bronchioloalveolar carcinomas are presented. In both cases, chest CT demonstrated widespread ground-glass shadows. The findings on CT revealed tumor tissue character with tumor cell proliferation along the alveolar wall and air in the alveoli.

A CT-pathologic correlative study concerning the nature of the tumor margin was performed in 22 lung cancer cases with solitary nodules in the peripheral lung field. Three of 14 adenocarcinoma cases showed an ill-defined margin and an adjacent subtle high attenuation area on CT, representing alveoli lined by tumor cells. In the other 11 cases, both ill- and well-defined margins were seen on CT. A well-defined margin of the mass represented alveoli filled entirely with mucinous material or tumor cells. In three of six squamous cell carcinomas an ill-defined margin in CT represented the infiltration of lymphatic cells surrounding the tumor and continuous spread of tumor cells from neighboring alveoli. A well-defined margin in the other cases and two small cell carcinoma cases represented alveoli filled entirely with tumor cells. CT was shown to be very useful in the assessment of the nature of the margin of the tumor.

Scintigraphy with 99mTc-technegas was recently introduced for clinical imaging of lung ventilation. This method has been found to be useful in emergencies, to be more suitable for single photon emission computed tomography (SPECT) than other agents used in ventilation scintigraphy, and could reveal abnormalities in ventilation more easily than high resolusion computed tomography (HRCT) in pulmonary emphysema. We compared 99mTc-technegas SPECT with HRCT in six regions: the right upper, middle, and lower lobes, the left upper lobe, the lingula, and the left lower lobe, in 15 patients with pulmonary emphysema. Patients with centrilobular emphysema tended to show stronger changes in upper lobes than in lower lobes on both 99mTc-technegas SPECT and HRCT. Some regions showed no change on HRCT but various changes on 99mTc-SPECT. Patients with panlobular emphysema showed severe changes on 99mTc-SPECT in lower lung fields in which well-demarcated areas of low attenuation were not seen on HRCT. We conclude that 99mTc-SPECT is useful for detecting early changes and panlobular changes in pulmonary emphysema.

Interstitial pulmonary emphysema (IPE) is the initial manifestation of ventilator-induced barotrauma. We report two patients in whom computed tomography was useful in showing IPE.

There have been previous reports on the differentiation of benign pulmonary nodules from malignant ones using CT number. However, most of the nodules were without calcification, and diagnosis could be made only in limited cases. In the present study we established new multiple variables such as relative high density over the 75th percentile, inner gradient number (inner irregular rate), edge gradient number (edge irregular rate) and increased area rate (IAR). They are automatically calculated from CT data by computer. These variables are transformed into relative values, enabling comparisons of nodules without a standard reference phantom. With IAR, pulmonary nodules were classified into three types: type 1 (IAR 1.0-1.4), a high-density solid mass with well-defined margin; type 2 (IAR 1.4-2.0) between type 1 and type 3; and type 3 (IAR > 2.0) a low-density infiltrated mass with ill-defined margin. We studied 52 cases with solitary pulmonary nodules, whose diagnoses were confirmed either histologically or on follow-up. There were 34 benign nodules and 18 primary lung cancers. Using step-wise multiple regression with three variables, 42 of 52 cases were correctly diagnosed. Twenty-four of 28 type 1 cases and all 14 of type 2 cases were correctly diagnosed. This computer analysis is considered to be useful in distinguishing between benign and malignant solitary pulmonary nodules.

This study was undertaken to assess the usefulness of technetium-99m technegas scintigraphy axial images (technegas) compared with high resolution CT (HRCT) in 12 patients with pulmonary emphysema. All patients were male adult and heavy smokers and their mean age was 65. All patients inhaled 505 MBq technegas in several tidal volume breaths in the supine position without breath holding. SPECT imaging was performed by a Picker model Prism 2000. HRCT was performed after technegas. The technegas images showed different degree of changes from areas of heterogeneity to hot spots or defects. In emphysema, HRCT images showed low attenuation areas varying in size and number. In 4 of 12 patients, the degree of abnormal findings on technegas increased according to the degree of abnormal findings on HRCT. In the remaining 8 patients, however, more detailed findings were shown by technegas than by HRCT. There was no patients in which HRCT showed a greater changes than on technegas. HRCT can demonstrate low attenuation areas, even less than 5 mm in diameter. Moreover previous reports showed that aerosol inhalation would also demonstrate the airway disease. Assessment of the degree of involvement revealed by both methods indicated the superiority of technegas over HRCT. We conclude that technegas can represent the ventilation involvement easily more than HRCT in pulmonary emphysema.

Percutaneous transhepatic gastrostomy was performed in two patients, one with partial gastrectomy and Billroth I anastomosis and one with esophageal reconstruction with subtotal stomach, in whom oral feeding was precluded. In both patients, percutaneous gastrostomy with fluoroscopic guidance was impossible since the gastric remnants were small, had a high subcostal position, and were overlain by the transverse colon, lung and left lobe of the liver. The only route available to avoid the overlying bowel and lung was the transhepatic approach. The gastric remnants were punctured with a 22-gauge PTC needle through the left lobe of the liver with CT guidance, and an 8 Fr. Cope-type catheter was fluoroscopically placed in the gastric remnant or the duodenum after tract dilatation over the guide wire. No complications occurred during or after the procedures, and the condition of both patients was greatly improved. Although gastrostomy in patients with partial gastrectomy is thought to be very difficult, percutaneous transhepatic gastrostomy with CT guidance is easy and may be safe since adhesion between the liver and gastric remnant can prevent massive hemorrhage or displacement of the catheters.