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 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*

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 usefulness of dynamic spiral computed tomography(CT) during the portal phase with ahigher IV injection rate of contrast material in detecting hepatic metastases. MATERIALS AND METHODS: We reviewed two-phase dynamic spiral CT in 44 patients with hepatic metastases of pathologically proven primary malignancy. One hundred and fifty ml. of non-ionic contrast material was administered with a power injector at a rate of 5ml/sec., and two-phase images at 55-80 sec.(portal phase) and 2-5 min.(equilibrium phase) were obtained after thestart of bolus injection. Two phase images were compared for detectability of hepatic metastases according tosize, number and enhancement pattern. RESULTS: In cases of metastases less than 1cm, 113 lesions(100%) that showed clearly defined hypodense lesions were detected in the portal phase of dynamic CT. However, the equilibriumphase images showed hypodense lesions in 58 cases(51%) and isodense lesions in 55cases(49%). In cases of metastases 1-2cm in size, the portal phase images detected 70 hypodense lesions(92%) and six hyperdense lesions(8%). In the equilibrium phase, however, the lesions were hypodense in 54 cases(71%), hyperdense infour(5%), and isodense in 18(24%). In cases of metastases larger than 2 cm, portal phase images showed 29 hypodense lesions(97%) and one hyperdense lesion(3%). In the equilibrium phase, however, the lesions were hypodense in 25 cases(83%), hyperdense in two(7%), and mixed in three(10%). As compared with the portal phase, most metastatic lesions were detected as poorly defined hypodense or isodense lesions in the equilibrium phase and decrease in size due to peripheral enhancement. CONCLUSION: Dynamic spiral CT during the portal phase with a higher IV injection rate(5 ml/sec) of contrast material is a useful method for detecting hepatic metastases, especially small lesions less than 1cm.
Humans ; Liver* ; Neoplasm Metastasis* ; Tomography, Spiral Computed*

PURPOSE: To determine the different of enhancement patterns of hepatic hemangioma according to the lesionsize, using dual-phase spiral CT. MATERIALS AND METHODS: Fify-nine lesions in 45 patients with hepatichemangiomas were subjected to spiral Ct. According to size, the lesions were divided into two groups(< 2.5cm :n=34 ; >_2.5cm : n=25). The enhancement patterns of the lesions were classified as one of four types (homogeneoushyperdense, peripheral hyperdense, central hyperdense, or hypodense) during the early phase, and as one of fivetypes homogeneous hyperdense, peripheral hyperdense, central hyperdense, hypodense or isodense) during the delayedphase. We evaluated differences in enhancement patterns during the early and delayed phase according to lesionsize. RESULTS: During the early phase, the enhancement patterns of lesions large than 2.5cm were peripheralhyperdense(96%) or homogeneous hyperdense (4%);those of less than 2.5cm were peripheral hyperdense (53%),homogeneous hyperdense(26%), hypodense(18%), or central hyperdense(3%). Thus, hemangiomas in these two groupsusually showed a peripheral enhancement pattern during the early phase, but in those which were smaller than2.5cm, atypical enhancement patterns were more common. During the delayed phase, the enhancement patterns oflesions larger than 2.5cm were peripheral hyperdense (60%) or homogenous hyperdense (40%), while the patterns ofthose smaller than 2.5cm were homogeneous hyperdense (67%), peripheral hyperdense (24%), central hyperdense (3%),hypodense (3%), or isodense (3%). Thus, the enhancement patterns of lesions larger than 2.5cm were usuallyperipherally hyperdense during the delayed phase, while those smaller than 2.5cm showed a homogeneous enhancementpattern. CONCLUSION: The enhancement patterns of hepatic hemangiomas differ according to lesion size. A knowledgeof these differences is helpful in the diagnosis of hepatic hemangioma.
Diagnosis ; Hemangioma* ; Humans ; Tomography, Spiral Computed*

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.
Endoscopy ; Gastroscopy* ; Humans ; Tomography, Spiral Computed* ; Ulcer

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 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

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*