Comparison between Spiral CT and MR Imaging in Evaluation of Focal Hepatic Masses

PURPOSE: The main aim of this study was to compare spiral CT and MR imaging in the detection and characterization of focal hepatic masses. MATERIALS AND METHODS: Seventy-nine patients with 155 focal hepatic masses confirmed pathologically, or radiologically and clinically [hepatocellular carcinoma(HCC) (n =52), hemangioma (n=36), cysts (n =35), metastasis (n =27), intrahepatic cholangiocarcinoma (n =5)], underwent two- or three-phase spiral CT, and T1-, T2- weighted, and dynamic contrast-enhanced MR imaging. The detection and characterization of focal hepatic masses by these modalities were evaluated and compared. RESULT: The detection rates of spiral CT and MR imaging, respectively, were as follows: HCC, 81%(42/52) and 94%(49/52); hemangioma, 75%(27/36) and 100%(36/36); cysts, 80%(28/35) and 100%(35/35); metastasis, 67%(18/27) and 100%(27/27); and intrahepatic cholangiocarcinoma, 100%(5/5) and 100%(5/5). MR imaging was superior to spiral CT in mass detection of HCC, hemangioma, cysts, and metastasis (p < .05). The characterization rates of spiral CT and MR imaging, respectively, were as follows: HCC, 52%(27/52) and 71%(37/52); hemangioma, 67%(24/36) and 100%(36/36); cysts, 63%(22/35) and 100%(35/35); metastasis, 37%(10/27) and 100%(27/27); and intrahepatic cholangiocarcinoma, 40%(2/5) and 80%(4/5). In the mass characterization of HCC, hemangioma, cysts, and metastasis, MR imaging was superior to spiral CT (p< .05). CONCLUSION: In the detection and characterization of focal hepatic masses, including hepatocellular carcinoma, hemangioma, hepatic cyst and metastasis, MR imaging is superior to spiral CT.

Usefulness of CT Angiogra p hy after Metallic Stent Implantation of the Internal Carotid Artery

PURPOSE: To evaluate the usefulness of CT angiography in Patients with implantation of metallic stent for stenosed internal carotid artery. MATERIALS AND METHODS: Seven patients with atherosclerotic stenosis of the internal carotid artery underwent metallic stent implantation. All were male and their ages ranged from 36 to 69 years. A total of seven stents were placed in the internal carotid artery in five patients and in the carotid bifurcation in two. Spiral CT scans were obtained and CT angiographic images were reconstructed using MPR or curved MPR techniques at a workstation. The interval between CT and conventional angiography did not exceed six days except in one patient, in whom it was 61days. CT and conventional angiography were compared for stent position with respect to the carotid bifurcation, stent deformation, intraluminal filling defect, and luminal caliber and outflow. Luminal patency of the implanted stent was measured according to NASCET(North American Symptomatic Carotid Endarterectomy Trial) criteria, and statistically processed (p<.05). The presence or absence of intrastent thrombus and vascular wall calcification was determined using axial source images. RESULTS: In all patients, CT angiographic findings matched those obtained by conventional angiography. Complications such as migration or deformation of an implanted stent, intraluminal filling defect, change of luminal caliber or outflow of implanted stent were not observed in any patient. In two studies in which Wilcoxon signed rank test was used, degree of stent expansion correlated closely(p=0.237). Axial source images showed that in no patient was an intrastent thrombus present, though in five, vascular wall calcification of internal carotid arteries outside the stent was noted. CONCLUSION: CT angiography is useful for the assessment of positional change, occlusion, and luminal patency of a stent-implanted internal carotid artery.

Lumbosacral Lipoma: Gadolinium-Enhanced Fat Saturation T1 Weighted MR Image is Necessary?

PURPOSE: To evalute the usefulness of contrast-enhanced fat saturation T1-weighted imaging for the evaluationof spinal lipoma, compared with clinical symptoms and surgical findings. MATERIALS AND METHODS: Ten patients withlipomyelomeningocele, confirmed by surgery, were included in this study. In all cases, conventional spin echoT1-and T2-weighted MR imaging, and contrast-enhanced fat saturation T1-weighted imaging was performed to evaluateclinical symptoms, the position of the conus medullaris, the prescence of cord tethering, and associatedanomalies, and to compare the relative usefulness of the techniques. RESULTS: All ten patients were sufferingfrom lipomyelomeningocele without filum terminale fibrolipoma or intradural lipoma. All cases were associated withcord tethering. As associated anomalies, there were seven cases of syringomyelia without hydrocephalus oranorectal anomaly. To evaluate the position of the spinal conus and the prescence of cord tethering, conventionalT1-weighted imaging was more useful than the contrast-enhanced fat saturation equivalent. CONCLUSION: In patientswith early-stage spinal lipona, MRI is useful for evaluation of the causes and position of cord tethering andassociated anomalies Our results suggest that contrast-enhanced fat saturation T1-weighted images do not provideadditional information concerning spinal lipoma, and that for the diagnosis of this condition, conventional T1 and T2-weighted images are more useful than those obtained by contrast-enhanced fat saturation T1-weighted imaging.

Virtual Gastroscopy Using Spiral CT in Gastric Lesions

PURPOSE: To compare virtual gastroscopy using spiral CT with conventional endoscopy for the detection andevaluation of gastric lesions. MATERIALS AND METHODS: During a previous six-month period, 30 patients withpathologically-proven gastric lesions underwent conventional endoscopy and virtual gastroscopy using spiral CT.There were 18 cases of advanced gastric carcinoma, eight benign ulcers, and four submucosal tumors(two leiomyomas,two lymphomas). Source images of virtual gastroscopy were three-dimensionally reconstructed within an AdvantageWindows Workstation and virtual gastroscopy images were obtained using Navigator Software. On analysis, imageswere graded according to their quality (excellent, good, poor). Virtual gastroscopy images were interpreted by tworadiologists blinded to conventional endoscopic findings, and were subsequently compared with endoscopic findingsin terms of detectability and findings. In the cases of advanced gastric carcinoma, lesions were classifiedaccording to Borrmann's system. RESULTS: For virtual gastroscopy, overall image quality was excellent in 21cases(70%), good in five(17%), and poor in four(13%). Lesions were detected in 25 cases(83%). Among the 18advanced gastric carcinomas, virtual gastroscopy image quality was excellent in 14 cases(78%), good in two(11%),and poor in two(11%). Lesions were detected in 16 cases(89%). Two Borrmann type IV cases were not detected. Amongthe eight benign ulcers, virtual gastroscopy image quality was excellent in three cases(38%), good in three(38%),and poor in two(25%). The detection of lesion was possible in five cases(63%). In all submucosal tumors, virtualgastroscopy image quality was excellent. Lesions were detected in all cases. CONCLUSION: Virtual gastroscopyusing spiral CT is safe and noninvasive, and for the evaluation of gastric lesions may be complementary to axialCT. It successfully detects gastric lesions, and in depicting the pattern of gastric folds its image quality isexcellent.