Multi-slice spiral CT has been an outstanding progress in developmental history of CT technology. The technical indexes of all three respects, ie scanning range time and spatial resolution are all marked improved. And several robust post-processing techniques have been imported into CT data post-scanning reconstruction, which help massive volume data being sufficiently and optimally interpreted. Therefore, newer advances have been achieved both in clinical applications and diagnostic efficacy.
Tomography, Spiral Computed ; methods

PURPOSE: To evaluate contrast enhancement patterns of hemangioma according to size, as seen during thearterial and portal venous phase of spiral CT. MATERIAL AND METHODS: During a recent six month-period, 52patients with hemangiomas underwent two-phase spiral CT examination with 10mm collimation at 10mm/sec table speed,and with 100mL of contrast material(37g iodine) injected at a rate of 2.5 mL/sec. CT images of the hepaticarterial and portal venous phase were obtained with 30-second and 65-second delay, respectively. In 52 patients,82 hemangiomas were seen. The diameter of the tumors were as follows ; < or =10 mm(n=31), 11-20 mm(n=19), and> or =21mm(n=32). The enhancement patterns of tumors compared with attenuation of surrounding liver parenchyma weredivided into four types : peripheral high, uniform high, iso, and low. RESULTS: Overall, the most commonenhancement pattern was peripheral high(44/82, 53.7%), during the arterial and portal venous phase. The second andthird most common patterns were uniform high(11/82, 13.4%) and peripheral high-uniform high(9/82, 11.0%), alsoduring the arterial and portal venous phase. Sixty-one(74.4%) showed peripheral high attenuation andeleven(13.4%), uniform high attenuation, during the arterial and/or portal venous phase. In tumors smaller than20mm, low-low attenuation was seen in eight(9.8%), and iso-low attenuation in two(2.4%), during the arterial andportal venous phase, respectively. CONCLUSION: On two-phase spiral CT, the most common enhancement pattern ofhemangioma was peripheral high, seen during the arterial and portal venous phase. However, a small hemangioma lessthan 2 cm may show atypical patterns, including low and iso attenuation.
Hemangioma* ; Liver ; Tomography, Spiral Computed*

PURPOSE: To determine whether triple-phase multi-detector-row helical CT images of the liver improves the detection rate of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Forty-one patients with 103 HCCs underwent triple-phase multi-detector-row helical CT imaging of the entire liver after contrast administration. Early and late arterial phase images were obtained serially during a single breath-hold, and portal venous-phase images were then obtained. Each image set was independently assessed for the presence of HCC by two radiologists unaware of the possible presence of tumors, and for each phase the detection rate was determined. For each arterial-phase image, lesion conspicuity (attenuation of a tumor compared with that of its parenchyma) was calculated. RESULTS: For reader 1, the detection rates for the early arterial, late arterial, and portal venous phase were 81%, 77%, and 55%, respectively, and for reader 2 were 83%, 81%, and 68%, respectively (p>0.05). When triplephase imaging findings were combined, the detection rate was significantly higher than when only those of the early or late arterial, and portal venous, phase were used (p<0.05). Mean lesion conspicuity for the late arterial phase was higher than for the early arterial phase, but the difference was statistically insignificant (p>0.05). CONCLUSION: Triple-phase imaging of the liver, involving the early arterial, late arterial, and portal venous phase, and using multi-detector-row helical CT, increases the detection rate of HCC.
Carcinoma, Hepatocellular ; Humans ; Liver* ; Tomography, Spiral Computed*

PURPOSE: To evaluate the usefulness of the reconstructed 3-dimensional image on the personal computer in comparison with that of the CT workstation by quantitative comparison and analysis. MATERIALS AND METHODS: The spiral CT data obtained from 27 persons were transferred from the CT workstation to a personal computer, and they were reconstructed as 3-dimensional image on the personal computer using V-works 2.0(TM). One observer obtained the 14 measurements on the reconstructed 3-dimensional image on both the CT workstation and the personal computer. Paired t test was used to evaluate the intraobserver difference and the mean value of the each measurement on the CT workstation and the personal computer. Pearson correlation analysis and % incongruence were also performed. RESULTS: I-Gn, N-Gn, N-A, N-Ns, B-A, and G-Op did not show any statistically significant difference (p>0.05), B-O, B-N, Eu-Eu, Zy-Zy, Biw, D-D, Orbrd R, and L had statistically significant difference (p<0.05), but the mean values of the differences of all measurements were below 2 mm, except for D-D. The value of correlation coefficient gamma was greater than 0.95 at I-Gn, N-Gn, N-A, N-Ns, B-A, B-N, G-Op, Eu-Eu, Zy-Zy, and Biw, and it was 0.75 at B-O, 0.78 at D-D, and 0.82 at both Orbrd R and L. The % incongruence was below 4% at I-Gn, N-Gn, N-A, N-Ns, B-A, B-N, G-Op, Eu-Eu, Zy-Zy, and Biw, and 7.18%, 10.78%, 4.97%, 5.89% at B-O, D-D, Orbrd R and L respectively. CONCLUSION: It can be considered that the utilization of the personal computer has great usefulness in reconstruction of the 3-dimensional image when it comes to the economics, accessibility and convenience, except for thin bones and the landmarks which are difficult to be located.
Humans ; Microcomputers* ; Skull* ; Tomography, Spiral Computed

We report a case of Rasmussen aneurysm diagnosed by helical CT that well shows vascular imaging. Coil embolization of Rasmussen aneurysm stopped the bleeding successfully.
Aneurysm* ; Embolization, Therapeutic* ; Hemorrhage ; Tomography, Spiral Computed*

PURPOSE: To determine the incidence of hepatic hemangiomas associated with wedge-shaped parenchymal enhancements adjacent to the tumors as seen on two-phase spiral CT images obtained during the hepatic arterial phase and to characterize the two-phase spiral CT findings of those hemangiomas. MATERIALS AND METHODS: One hundred and eight consecutive hepatic hemangiomas in 63 patients who underwent two-phase spiral CT scanning during an 11-month period were included in this study. Two-phase spiral CT scans were obtained during the hepatic arterial phase(30-second delay) and portal venous phase(65-second delay) after injection of 120mL of contrast material at a rate of 3mL/sec. We evaluated the frequency with which wedge-shaped parenchymal enhancement was adjacent to the hemangiomas during the hepatic arterial phase and divided hemangiomas into two groups according to whether or not wedge-shaped parenchymal enhancement was noted (Group A and Group B). The presence of such enhancement in hemangiomas was cor-related with tumor size and the grade of intratumoral enhancement. RESULTS: In 24 of 108 hemangiomas, wedge-shaped parenchymal enhancement adjacent to hepatic tumors was seen on two-phase CT images obtained during the hepatic arterial phase. Mean hemangioma size was 22mm in Group A and 24mm in Group B. There was no statistically significant relationship between lesion size and the presence of wedge-shaped parenchymal enhancement adjacent to a hemangioma. In 91.7% and 1 00% of tumors in Group A, and in 9.6% and 17.8% in Group B, hemangiomas showed more than 50% intra-tumoral enhancement during the arterial and portal venous phase, respectively. Wedge-shaped parenchymal enhancements peripheral to hepatic hemangiomas was more frequently found in tumors showing more than 50% intratumoral enhancement during these two phases(p<0.01). CONCLUSION: Wedge-shaped parenchymal enhancements is not uncommonly seen adjacent to hepatic heman-giomas on two-phase spiral CT images obtained during the hepatic arterial phase. A hemangioma showing-wedge-shaped parenchymal enhancement tends to show more than 50% intratumoral enhancements during the arterial and portal venous phase.
Hemangioma* ; Humans ; Incidence ; Tomography, Spiral Computed*

Primary malignant melanoma of the esophagus is extremely rare, but must be included in the differential diagnosis of polypoid esophageal mass, when such a lesion is observed on radiological examination. We report here a case of primary malignant melanoma in the esophagus that was noted to have strong enhancement on CT and high signal intensity on the T1 weighted MR image.
Diagnosis, Differential ; Esophagus* ; Melanoma* ; Tomography, Spiral Computed*

PURPOSE: To determine the enhancing patterns of hepatocellular carcinoma(HCC) and the difference of enhancing patterns according to the tumor size, using spiral CT. MATERIALS & METHODS: We reviewed 213 lesions in 76patients who had been clinically or histopathologically diagnosed as HCC sufferer. The tumors were divided into three groups, according to size(&3 cm, 3-5cm and >5 cm). The enhancing patterns of tumor and capsule in the earlyand delayed phase were analysed. The enhancing patterns of the tumor were divided into five types(high, peripheralhigh, mixed, iso and low attenuation) in the early phase and four types(central high, mixed, iso, and low attenuation) in the delayed phase. The enhancing patterns of the capsule were divided into three types such asiso, low and high attenuation. RESULTS: High attenuating lesions in the early phase were as follows : below 3cm 72% ; 3-5cm., 60% ; above 5cm., 49%. Mixed attenuating lesions in the early phase were as follows : below 3cm., 1%; 3-5cm., 22% ; above 5cm., 36%. Thus, most HCCs were high attenuation type in the early phase, but as the tumorbecame larger, less high attenuation and more mixed attenuation was demonstrated(p<0.01). There was no difference of enhancing patterns according to the tumor size in peripheral high, iso and low-attenuating lesions. In the delayed phase most of the hepatomas appeared as totally hypodense lesions. For capsules, the results were as follows : below 3cm., 20% ; 3-5cm.,58% ; above 5cm., 73%. As the tumors became larger, more capsules were demonstrated(p <0.01). The capsules were visualized as iso or low attenuating rim in the early phase and high attenuating rim in the delayed phase. CONCLUSIONS: To determine the enhancing patterns of HCC using spiral CT is considered to be helpful in the diagnosis of HCC.
Capsules ; Carcinoma, Hepatocellular* ; Diagnosis ; Tomography, Spiral Computed*

PURPOSE: To evaluate the relative value of arterial, portal venous and delayed phase images of spiral CT in the detection of metastatic tumor of the liver. MATERIALS AND METHODS: Forty-three metastatic tumors in twelve patients were underwent tri-phasic spiral CT examination with injection of 120 ml ionic contrast material (36 g of iodine) at the rate of 3 ml/sec. Arterial, portal venous and delayed phase CT images were obtained 35, 65, and 360 seconds after the start of contrast injection, respectively. RESULTS: Arterial phase images detected 35(81%), portal venous phase images 43(100%), and delayed phase images 34(79%) lesions, respectively(p<0.05). All masses larger than 2cm(n=23) were detected in all three phases, whereas 60%, 100%, 55%of the masses smaller than 2cm(n=20) were detected in arterial, portal venous and delayed phase CT, respectively. The best contrast between masses and the hepatic parenchyma was in portal venous phase followed by arterial and delayed phase(p<0.01). In two hypervascular masses, the contrast was better in arterial phase. CONCLUSION: Portal venous phase of spiral CT is optimal in the detection of metastatic tumor of the liver. Arterial phase may be helpful for the detection of hypervascular metastasis. Delayed phase should be used restrictively.
Humans ; Liver* ; Neoplasm Metastasis ; Tomography, Spiral Computed*

PURPOSE: To evaluate the efficacy of two-phase dynamic helical CT, including the gastric mucosal phase, for the detection of atypical non-hyperattenuating early gastric carcinoma (EGC). MATERIALS AND METHODS: In 32 patients, we evaluated the two-phase helical CT findings of endoscopically suspected EGC for changes of the inner hyperattenuating mucosal layer, the hypoattenuating outer layer and the serosal surface. Two gastrointestinal radiologists working together reached their conclusions before pathologic diagnosis had been made. The first, so-called gastric mucosal, phase was obtained 38 -45 sec after the start of IV injection of 150 ml/sec contrast material at a rate of 4 ml/sec to obtain maximum enhancement of the mucosal layer. RESULTS: Among 32 patients, EGC was confirmed in 30 and AGC (T2) in two. Using two-phase helical CT, the detection rate for typical hyperattenuating EGC was 27 % (8/30). Lesions showing focal interruption of the mucosal layer without abnormal enhancement of the outer layer (EGC atypical enhancement pattern type 1) were detected in five patients during the mucosal phase, and were pathologically confirmed as 3 EGC IIc+III, 1IIc+IIa, and I IIb+IIc. Lesions showing a locally protuding lesion of the inner and preserved outer layers, with a smooth serosal surface (EGC atypical enhancement pattern type 2) and which could be distinguished from normal folds, were detected in six patients during the mucosal phase, and were pathologically confirmed as 2 EGC IIb+IIc, 1 IIc+IIa, and 3 IIc+IIb. Lesions were less distinct during the equilibrium phase, and there was no change in the enhancement pattern. The overall detection rate for EGC in which an atypical enhancement pattern was added to the typical one showed improvement (19/30, 63 % ). CONCLUSION: Helical CT using a two-phasic scan technique including the mucosal phase was efficient for various combinations of EGC II and/or III, including IIc. The findings were atypical and non-hyperattenvating, but reliable, and improved the overall detection rate.
Diagnosis ; Humans ; Stomach Neoplasms* ; Tomography, Spiral Computed*