Chul Hi Park

64 multidetector-row computed tomography for preoperative evaluation of gastric cancer: histological correlation.

Objective: To assess the accuracy of 64 multidetector-row computed tomography (MDCT) in the diagnosis and staging of gastric cancer. Methods: This study was approved by the institutional review board, and the patients involved gave informed consent. Forty-four patients (34 men and 10 women; mean age, 57 years) with gastric carcinoma underwent preoperative 64 MDCT (SOMATOM Sensation 64; Siemens Medical System, Forchheim, Germany; slice collimation, 0.6 mm; slice width, 5 mm; feed/rotation, 23 mm; pitch factor, 1.2; kernel, B30f; and gantry speed, 0.5 second per rotation). Gastric distension was achieved by ingestion of 8 g of effervescent granules. Scanning was performed during arterial and portal phases, as determined with bolus tracking and automated triggering technique after intravenous administration of 100 mL of contrast materials (4 mL/s). All computed tomography scans were retrospectively reviewed by 2 radiologists. Each tumor was staged according to the TNM classification system. All patients underwent surgery. Computed tomography results were compared with histological staging of tumor invasion depth and regional lymph node metastasis. Results: The accuracy of 64 MDCT for detection of gastric cancer was 90% (18/20) and 100% (24/24) in early and advanced gastric cancer, respectively, with an overall detection rate of 95% (42/44). Its accuracy for determination of tumor penetration depth was 89% (16/18) and 88% (21/24) in early and advanced gastric cancer, respectively, with an overall accuracy of 88% (37/42). Its accuracy for determination of lymph node metastasis was 90% (18/20) and 71% (17/24) in early and advanced gastric cancer, respectively, with an overall accuracy of 80% (35/44). Conclusions: The 64 MDCT is a promising technique for the detection and preoperative staging of gastric cancer.

Multidetector computed tomography chest examinations with low-kilovoltage protocols in adults: effect on image quality and radiation dose.

Objective: The purpose of our study was to assess the effect on image quality and radiation dose of chest multidetector computed tomography (CT) examinations with low-kilovoltage protocols for adults. Methods: This study was approved by the institutional review board of our medical center. Two hundred ten patients (83 women, 127 men; mean age, 56.1 years) requiring contrast-enhanced chest CT examination were randomly assigned to 1 of 3 protocol groups: (1) protocol A, the standard protocol, with 120 kilovolt (peak) (kV[p]) and 100 effective milliampere-second (eff mA s); (2) protocol B, with 100 kV(p) and 140 eff mA s; and (3) protocol C, with 80 kV(p) and 180 eff mA s. Each group included 70 patients. Contrast material injection protocols were standardized for all groups. Three radiologists blinded to the CT parameters used assessed images in random order for 20 items from 4 anatomical regions. They ranked the subjective image quality using a 4-point scale. The volume computed tomography dose index (CTDIvol) and dose length product (DLP) were displayed by the CT unit after the automatic exposure control-driven acquisition was recorded for each group; the differences were analyzed for statistical significance. Results: When the overall agreement was pooled from the 3 observers, the qualitative score analysis revealed no significant difference between the 100-kV(p) and the standard protocols (P > 0.05). However, when the scores were compared between the 80-kV(p) and the standard protocols, a marginal significance (P = 0.054) was observed. When the patients in the group with an 80-kV(p) protocol were subcategorized according to body mass index (BMI), the image quality scores of all BMI subgroups, of the 80-kV(p) protocol, were not significantly different from those of the standard protocol. However, an increase in the BMI tended to be associated with a decrease in the subjective image quality. The mean values of CTDIvol for 120-, 100-, and 80-kV(p) protocols were 5.042, 4.507, and 2.883, respectively. The mean values of DLP for each protocol were 187.5, 158.7, and 105.8, respectively. The CTDIvol and DLP of the low-kilovoltage protocols were significantly lower than those of the standard protocol (P < 0.01). The DLP of the 100- and 80-kV(p) protocols were reduced radiation exposure doses in 15.36% and 43.57%, respectively, as compared with the standard protocol. Conclusions: The use of low-kilovoltage protocol resulted in a significant reduction in the radiation exposure at chest CT, with image qualities comparable with those of the standard protocols.

Complications of pyogenic hepatic abscess. Computed tomography and clinical features

The purpose of this pictorial essay is to describe the computed tomography (CT) and clinical findings of the various complications of pyogenic hepatic abscesses. The CT and clinical findings of 81 patients who had a confirmed pyogenic hepatic abscess were analyzed retrospectively. Of the 81 patients, 21 cases of various complications from the pyogenic hepatic abscesses were encountered in 17 patients (21%). Two types of complications were observed in 4 patients. These complications included rupture into the pericardial cavity (n = 1), pleuropulmonary complications (n = 11), rupture into the gastrointestinal tract (n = 1), rupture into the peritoneal cavity (n = 3), rupture into the retroperitoneum (n = 1), vascular complications (n = 3), and biliary complications (n = 1). A knowledge of these complications is important for an early diagnosis and appropriate management.

Anomaly of the portal vein with total ramification of the intrahepatic portal branches from the right umbilical portion: CT features.

Purpose: To describe CT findings of portal vein anomaly with total ramification of the intrahepatic portal branches from the right umbilical vein. Methods: Retrospective analysis was performed in 6 patients with portal vein anomaly with total ramification of the intrahepatic portal branches from the right umbilican vein. We analyzed the position of the umbilical portion of the portal vein and ligamentum teres, and determined the intrahepatic branching pattern of the portal vein. Results: The umbilical portion and ligamentum teres were deviated to the right and seen above the gallbladder fossa in all 6 patients. All major braches of the portal vein ramified from the right umbilical vein in all 6 patients. Conclusion: The possibility of this portal vein anomaly should be kept in mind when hepatic resection or partial liver transplantation is required.

Computed tomography and sonographic findings of hepatic metastases from gastrointestinal stromal tumors after chemotherapy

Objective: The purpose of this study was to evaluate the computed tomography (CT) and sonographic findings in patients with hepatic metastases from gastrointestinal stromal tumors (GISTs) after STI-571 treatment. Methods: Computed tomography and sonographic findings of 8 lesions in 6 patients with hepatic metastases from GISTs that were treated with STI-571 were retrospectively analyzed. The change in size, attenuation, and echogenicity of the hepatic metastases from GISTs after STI-571 treatment was evaluated. Results: After treatment with STI-571, the hepatic metastases were decreased in size and the attenuation of the hepatic metastases was homogeneously hypodense on CT. Sonography revealed the hepatic metastases to be centrally cystic with a thin wall (n = 4) or predominantly solid (n = 4) after STI-571 treatment. On color Doppler sonography, no blood flow was identified within the solid portion of the mass. Conclusion: After treatment with STI-571, although the hepatic metastases from GISTs exhibit a cystic appearance on CT, they may appear as solid masses on sonography.

Utility of MR Cholangiography for Follow-up Examination after Metallic Stent Placement in the Bile Duct

Purpose: To evaluate the efficacy of MR cholangiography for follow-up examination after metallic stent placement in the bile duct. Materials and Methods: Between December 1999 and June 2000, 15 patients with biliary obstruction in whom metallic biliary stents had been placed underwent MR cholangiography during follow-up examination. The causes of obstruction were hilar cholangiocarcinoma (n=6), common bile duct cancer (n=5), gall bladder cancer (n=1) and pancreatic cancer (n=3). The types of self-expandable metallic stent employed were the nitinol stent (n=2), the Endocoil nitinol stent (n=3), the Ultraflexed Diamond stent (n=5), and the Wallstent (n=5). Using MR cholangiography, we measured the diameter of that part of the biliary stent which showed high signal intensity, assigning one point if this was less than one third of the stent diameter, two points if between one third and two thirds, and three points if more than two thirds. We decided that a higher score indicated fewer artifacts. Results: The score was 1.7-3 (mean, 2.3) points for the Endocoil nitinol stent, 1.7-2.3 (mean, 2) for the nitinot stent, and 1-3 (mean, 1.7) for the Ultraflex Diamond stant. In most cases, two thirds of the stent diameter was observed. For the Wallstent, the score was 1-1.7 (mean, 1.3) points and the inner portion of the stent was almost invisible. Conclusion: MR cholangiography is not useful for follow-up examination after the placement of Wallstents and three other types of nitinol stent in the bile duct.