Soo Yil Chin

Diagnosis of Recurrent Uterine Cervical Cancer: Computed Tomography versus Positron Emission Tomography

Objective To determine the accuracy of CT and positron emission tomography (PET) in the diagnosis of recurrent uterine cervical cancer. Materials and Methods Imaging findings of CT and PET in 36 patients (mean age, 53 years) in whom recurrent uterine cervical cancer was suspected were analyzed retrospectively. Between October 1997 and May 1998, they had undergone surgery and/or radiation therapy. Tumor recurrence was confirmed by pathologic examination or follow-up studies. Results In detecting recurrent uterine cervical cancer, the sensitivity, specificity, and accuracy of CT were 77.8%, 83.3%, and 80.5%, respectively, while for PET, the corresponding figures were 100%, 94.4%, and 97.2%. The Chi-square test revealed no significant difference in specificity (p = .2888), but significant differences in sensitivity (p = .0339) and accuracy (p = .0244). Conclusion PET proved to be a reliable screening method for detecting recurrent uterine cervical cancer, but to determine the anatomical localization of recurrent tumors, and thus decide an adequate treatment plan, CT was eventually needed.

Ct Findings in Malignant Tumors of Thymic Epithelium

Objective Differentiation of invasive thymoma from thymic carcinoma is important because of their different clinical behaviors. Retrospectively, we evaluated the CT findings of invasive thymomas and thytnic carcinomas to determine the differential points between them. Materials and Methods We reviewed the CT scans of 12 patients with invasive thymoma and 10 patients with thymic carcinoma that were confirmed by surgery or percutaneous needle aspiration. We analyzed CT scans, paying special attention to homogeneity, attenuation, invasion of adjacent mediastinal structures, pleural implants, mediastinal nodes, and extramediastinal metastases. Results Most of the invasive thymomas and thymic carcinomas were homogeneous and isodense with chest wall muscle. Irregular infiltration into the adjacent organ suggesting invasion was seen in 11 patients (92%) with invasive thymoma and 8 patients (80%) with thymic carcinoma. Pleural implants were observed in four patients (33%) with invasive thymoma and one patient (10%) with thymic carcinoma. Mediastinal lymphadenopathy was seen in one patient (8%) with invasive thytnotna and four patients (40%) with thytnic carcinoma. Metastases to the lung, adrenal glands, or liver were observed in four patients (40%) with thymic carcinoma but none with invasive thymoma. Conclusion Despite the similarities of CT findings between invasive thymoma and thymic carcinoma, there are some differential points. Thymic carcinomas were infiltrating tumor and were more commonly associated with mediastinal nodes and extrathymic metastases, but less commonly associated with pleural implants than invasive thymoma. Index Terms Thymus gland, neoplasms—Thytnotna—Computed tomography.

New Self-expandable Spiral Metallic Stent: Preliminary Clinical Evaluation in Malignant Biliary Obstruction☆

PURPOSE To describe a new self-expandable spiral-shaped metallic stent and to evaluate its clinical efficacy in malignant biliary obstructions. PATIENTS AND METHODS The stent was made of a 0.01-inch (0.25-mm) stainless steel wire bent in a zigzag pattern and was formed into a spiral configuration by differing the length of legs on each bend. One revolution was composed of 10 bends, and the stent was longitudinally connected by hanging each bending point of abutting bends, without use of suture or silver solder. Twenty-six stents were placed to relieve malignant biliary obstruction in 18 patients. Follow-up of 5-11 months (mean, 7 months) was obtained. RESULTS All stents were placed in the desired location, and no procedural complications were encountered. Within 1 week after placement, all stents regained 90% or more of their original diameters. Five patients died (range, 5-36 weeks), and 13 patients are still alive (range, 20-45 weeks). Two patients experienced recurrent jaundice and underwent further treatment. The stent was easily inserted, expanded well, was flexible, could be repositioned, and did not shorten. CONCLUSION Favorable clinical results were obtained with this spiral stent in malignant biliary obstruction, and further clinical testing is warranted.

Obstructive jaundice in gastric carcinoma: cause, site, and relationship to the primary lesion

ObjectiveObstructive jaundice is frequently present in patients with advanced gastric carcinoma. The purpose of this study was to assess the cause and preferential site of bile duct obstruction in patients with gastric carcinoma and to evaluate correlativity of biliary obstruction with the nature of the primary gastric lesion.MethodsCholangiographic findings of 54 patients with metastatic gastric carcinoma presenting with obstructive jaundice were reviewed retrospectively.The level of the bile duct obstruction was divided into four segments: segment 1, from an individual intrahepatic duct to the biliary hilum; segment 2, common hepatic duct (CHD) involvement from the biliary hilum to the level of the cystic duct; segment 3, the proximal half of the common bile duct (CBD); segment 4, the distal half of the CBD. To evaluate the characteristics of the primary gastric lesion, operative records and pathologic findings were reviewed.ResultsObstruction sites were segment 1 in eight patients (15%), segment 2 in 25 (46%), segment 3 in 17 (32%), and segment 4 in four (7%). The causes of obstruction were metastatic lymphadenopathy in the hepatoduodenal ligament (50 of 54) and direct invasion of the primary or recurrent tumor (four of 54). The location of the primary gastric lesions was the antrum, antrum and body, and body in 36 (67%), 17 (31%), and 1 (2%), respectively. Borrmann type 3 lesions were present in 72% of cases, and type 2 lesions in the remaining 24%. Histologic type was undifferentiated adenocarcinoma in 91% of patients, and differentiated adenocarcinoma in the remaining. Serosal invasion was shown in 96% of the patients.ConclusionOur results show that the cause of bile duct obstruction in advanced gastric carcinoma is predominantly metastatic lymphadenopathy in the hepatoduodenal ligament, and its preferential site is around the level of the cystic duct. Obstructing lesions showed characteristic cholangiographic findings.

Obliteration of the pulmonary vein in lung cancer : Significance in assessing local extent with CT

PURPOSE The purpose of this study was to evaluate the significance of obliteration of the pulmonary vein in assessing local extent of lung cancer with CT, particularly in regard to intrapericardial extension of tumor through the vein. METHOD Preoperative CT scans of 325 patients, who underwent thoracotomy for primary lung cancer, were reviewed. Among them, CT scans of 19 patients showed obliteration of the pulmonary vein up to its entrance into the left atrium, without filling defect in the left atrium. Surgical records of these patients were then reviewed to investigate the extent of tumor growth through the pulmonary vein, with particular emphasis on intrapericardial extension. RESULTS The surgical records revealed extension of tumor through the pulmonary vein beyond the pericardial reflection in 14 or 19 patients. In 10 patients showing obliteration of either the left of the right superior pulmonary vein, all tumors extended beyond the pericardial reflection (100%). Intrapericardial extension occurred in four of nine patients showing obliteration of either the left or the right inferior pulmonary vein (44%). The difference was statistically significant (p < 0.05). CONCLUSION When assessing local extent of lung cancer with CT, obliteration of the superior pulmonary vein is a highly suggestive finding for intrapericardial extension of tumor through the pulmonary vein. On the contrary, obliteration of the inferior pulmonary vein is believed to be a less reliable finding for intrapericardial extension of lung cancer.

Radiological prediction of the depth of invasion and histologic type in early gastric cancer

In cases of early gastric cancer (EGC), the depth of tumor invasion and histologic type are important factors in its prognosis. To predict the depth of invasion and histologic type by a double-contrast barium study of the stomach, 304 consecutive patients with EGC were analyzed, comparing barium study with pathologic findings. We predicted the depth of invasion and histologic type according to the lesion size, surface pat6ern, and surrounding mucosal pattern. The depth of tumor invasion was correctly diagnosed in 65.3% (66 of 101) of cancers limited to the mucosal layer (m), and in 59.1% (110 of 186) of cancers which have invaded to the submucosal layer (sm). The histologic type was correctly predicted in 78.9% (56 of 71) of a differentiated adenocarcinoma, and 73.1% (57 of 78) of an undifferentiated adenocarcinoma. Prediction of the depth of tumor invasion and histologic type was promising and showed good correlation to the pathologic findings.

Postpneumonectomy empyema:CT findings in six patients

Chest radiographs and CT scans, obtained in six patients with proven postpneumonectomy empyema, were retrospectively reviewed by comparing the radiologic image obtained at present with that obtained before symptom onset. Convexity or straightening of the concave mediastinal margin of the postpneumonectomy space was identified on CT scans in all of six patients (100%), while contralateral mediastinal shift was noted on both radiographs and CT scans in four patients (67%). Multiple air-fluid levels appeared equally on radiographs and CT scans in three patients (50%). CT depicted increased thickening of the parietal pleura (n=5, 83%) and the extrapleural tissues (n=3, 50%) and empyema necessitans (n=2, 33%), which were not apparent on radiographs. Postpneumonectomy empyema is characterized on CT scans by reversal of the normal concavity of the mediastinal margin with increased thickening of the residual parietal pleura. CT is superior to radiography in assessing the manifestations of postpneumonectomy empyema.

CT Findings of Pleural Dissemination from Lung Cancer

Purpose: The purpose of our study was to identify the CT findings that help detect pleural dissemination from lung cancer and to evaluate the usefulness of selected diagnostic criteria. Materials and Methods: After a computerized database search of 606 patients who had undergone thoracotomy for primary lung cancer, 23 patients were identified as h aving surgically documented pleural dissemination. From the same database, 50 pa-tients without pleural dissemination during thoracotomy were randomly selected as controls. Preoperative CT scans and medical records were rev i ewed retrospectively, and findings were compared between the two groups. Results: One or more of three types of pleural thickening (plaque-like, nodular, and fissural) were identified on CT as the most discriminating finding (sensitivity, 74 % ; specificity, 60 %; p = 0.007). The following findings were also significantly discriminating (p

Liposarcoma : MR Findings in the Histologic Subtypes

Purpose : To evaluate the MR imaging findings of liposarcomas of different histologic subtypes. Materials and Methods : We evaluated MR images of 21 patients (5 men and 16 women, mean age, 55 years) with liposarcoma and correlated the findings with the results of histopathology. In the study group seven liposarcomas were well-differentiated, seven were myxoid, three were mixed, two were pleomorphic, and one was round cell. Results :On T1 -and T2 - weighted images, six of seven well-differentiated liposarcomas showed signal intensity equal to the fat and hypointense septa, while the other showed low signal intensity on a T1 -weighted image, heterogeneoushigh signal intensity on a T2- weighted image, heterogeneous enhancement after the administration of contrastmedia and was dedifferentiate. Nine masses in seven patients with myxoid liposarcoma showed low signal intensityon T1-weighted images, six of the nine showed lace-like foci of high signal intensity. On T2 -weighted images, all masses showed homogeneous high signal intensity. After administration of contrast media, five of seven masses showed heterogeneous enhancement. Two of three mixed form were well-differentiated and myxoid types, and two subtypes were separable on MR. Pleomorphic, round cell, mixed type myxoid and pleomorphic and unclassified cases showed low signal intensity on T1-weighted images, heterogeneous high signal intensity on T2-weighted and heterogeneous enhancement. Conclusion : Using MR imaging, well-differentiated and myxoid liposcarcomas may be differentiated from other types.

MR Imaging of Osteosarcoma: Emphasis on Joint Involvment

Purpose : To evaluate MR imaging findings of joint involvement in patients with osteosarcoma Materials and Methods : Among 166 patients with osteosarcoma treated between January 1993 and July 1998, 67(44 men and 23 women, mean age 20 years) whose tumors had invaded the epiphysis were included in this study. Those with preserved normalbone marrow signal intensity between the tumor and cortical bone were excluded. Tumors were located around the knee (n=52), the hip (n=7), the shoulder (n=5), the ankle (n=2), or the wrist (n=1). For all patients, pre-operative spin echo pre- and post-contrast enhanced MR images were obtained. In all cases, we assessed the presence or abscence of intrasynovial mass, intraarticular disruption of cortical bone and articular cartilage, and joint effusion, and also evaluated the mass around the cruciate ligaments of the knee. All patients underwent surgery and MR findings were correlated with the results of pathologic examinations. Results : In six patients the tumor was found to involve the knee joint. Sensitivity and specificity for the intrasynovial mass (n= 6), intraarticular disruption of cortical bone and articular cartilage (n= 19), mass around the cruciate ligaments (n=7), and joint effusion (n= 12) were 83.3%, 100%, 83.3%, 33.3% and 98.4%, 78.7%, 95.6%, 83.6%, respectively, while accuracy for the intrasynovial mass and mass around the cruciate ligaments was 97% and 94.2% respectively. Conclusion: If MR imaging indicates the presence of a mass in the synovial cavity or around the cruciate ligaments, this is suggestive MR findings of joint involvement.