Contrast-enhanced multi-detector row spiral computed tomography (MDCT) was introduced as a promising noninvasive method for vascular imaging. This study examined the accuracy of this technique for detecting significant coronary artery stenoses. Both MDCT (Sensation 16, Siemens, Germany, 12 x 0.75 mm collimation and 0.42 sec rotation speed, 120 kV, 500 effective mA, and 2.7 mm/rotation table-feed) and invasive coronary angiography (CAG) were performed on 61 patients (mean age 59.2 +/- 10, 44 men) who were suspected of having coronary artery disease. All patients were treated with atenolol (25 - 50 mg) prior to imaging and the heart rate was maintained below 65 beats per minutes during image acquisition. The images were reconstructed in the diastole around TI - 400 ms with a 0.5 mm increment and a 1.0 mm thickness. All coronary arteries with a diameter of 2.0 mm or more were assessed for the presence of a stenosis (> 50% luminal narrowing). Two independent radiologists who were unaware of the results of the invasive CAG evaluated the MDCT data, and the results were compared with those from the invasive CAG (interval 1- 27, mean 11 days). An evaluation of the CT coronary angiogram (CTCA) was possible in 58 of the 61 patients (95%). Image acquisition of the major coronary arteries including the left main trunk was available in 229 out of 244 arteries. Invasive CAG showed that 35 out of 58 patients had significant coronary artery stenoses by. patient analysis of those who could be evaluated showed that CT coronary angiography correctly classified 30 out of 35 patients as having at least 1 coronary stenosis (sensitivity 85.7%, specificity 91.3%, positive predictive value 93.8%, negative predictive value 80.8%). By analyzing each coronary artery, CAG found 62 stenotic coronary arteries in the 229 coronary arteries that could be evaluated. MDCT correctly detected 50 out of 62 stenotic coronary arteries and an absence of stenosis was correctly identified in 156 out of 167 normal coronary arteries (sensitivity 80.6%, specificity 93.4%, positive predictive value 81.9%, negative predictive value 92.8%). The non-invasive technique of MDCT for examining the coronary artery appears to be a useful method for detecting coronary artery stenoses with a high accuracy particularly with the proximal portion and large arteries.
Aged ; Coronary Stenosis/*radiography ; Female ; Humans ; Male ; Middle Aged ; Predictive Value of Tests ; Reproducibility of Results ; Sensitivity and Specificity ; *Tomography, Spiral Computed/standards

OBJECTIVETo study regular patterns of cone artifact resulted from interpolation algorithm of spiral CT.

METHODSBased on the principle of interpolation algorithm and back-projection reconstruction, a mathematical model of the reconstructed image was established to clarify the relation of the scanning parameters and the characteristics of the scanned object with the cone artifact. Experiments were carried out by a set of acrylic phantoms on siemens plus 4 CT scanners.

RESULTSThe artifact in the image was directly proportional to the table increment per gantry rotation of the scanner, and was positively correlated to the tangent of half cone-angle and inversely to the radii in the reconstruction plane of the phantom. The theoretical analysis was validated by experimental results.

CONCLUSIONThe cone artifact is related to the scanning parameters and the characteristics of the scanned object.

Algorithms ; Artifacts ; Computer Simulation ; Image Processing, Computer-Assisted ; methods ; standards ; Models, Theoretical ; Phantoms, Imaging ; Tomography, Spiral Computed ; instrumentation ; methods

OBJECTIVETo investigate the value and deficiency of Milan criteria for liver transplantation in patients with hepatocellular carcinoma (HCC).

METHODSBetween December 2001 and November 2005, 125 patients underwent orthotopic liver transplantation ( OLT), who measured up Milan criteria with preoperation computerized tomography (CT) scanning. The results of pre-transplant multidetector CT scan and post-transplant pathology were retrospectively analyzed, and survival rates were compared.

RESULTSPathology examination demonstrated that 97 cases met Milan criteria (77.6%), 26 cases exceeded Milan criteria,and the other 2 cases were diagnosed as nodular cirrhosis. The 1-,2-,3-,4- and 5-year survival rates for those met pre-transplant multidetector CT scanning pre-transplant met Milan criteria vs. those met post-transplant pathology post-transplant criteria were 92.0% vs. 92.8%, 87.2% vs. 90.7%, 86.4% vs. 89.7%, 86.4% vs. 89.7%, and 86.4% vs. 89.7%, respectively. There was no statistic significant difference (P > 0.05). The 1-,2-,3-,4- and 5-year survival rates were 73.0%, 65.4%, 61.5%, 61.5% and 61.5%, for those pathology exceed Milan criteria respectively. The difference between this group and each of the above two were statistically significant (P < 0.05).

CONCLUSIONSThe prognosis of OLT for HCC is good for those met Milan criteria by pre-transplant multidetector CT. Factors leading to poor prognosis such as portal vein tumor thrombi and lymphatic metastasis should be accurately evaluated avoiding for misjudgement.

Adult ; Aged ; Carcinoma, Hepatocellular ; diagnostic imaging ; pathology ; surgery ; Female ; Follow-Up Studies ; Humans ; Liver Neoplasms ; diagnostic imaging ; pathology ; surgery ; Liver Transplantation ; methods ; mortality ; standards ; Male ; Middle Aged ; Retrospective Studies ; Survival Analysis ; Survival Rate ; Tomography, Spiral Computed

OBJECTIVETo investigate the value of CT scanning in preoperative diagnosis of early cervical carcinoma.

METHODSAbdominal and pelvic CT scans (MPR pictures for 50 patients) in 102 cervical carcinoma patients proven by biopsy pathology were retrospectively analyzed and compared with surgical pathologic findings. The pathological stages included > or = Ia in 39 patients, Ib 1 in 35, Ib 2 in 21, IIa in 6, IIb in 1. The tumor detection ability, thickness of cervical tumor invasion, T stage and lymph node stage showed by CT scan were evaluated.

RESULTSCT was not able to detect < or = Ia cervical carcinoma, however, CT was able to detect tumors in 71.4% of > or = Ib 1 stage (45/63) and 71.4% > or = Ib 2 (20/28), it also showed the depth of tumor invasion in 39.7% > or = Ib 1 (25/63). The overall accuracy of CT staging for tumor was 69.6% and the rate of metastatic lymph node detection 63.6% (7/11). With additional MPR pictures of spiral CT, the detection ability, vaginal involvement and objective shape of cervical tumor was improved. The cervical carcinoma in CT scan was found to be as homogeneous in 54.9% of patients (56/102), hypodense or heterogeneous in 42.2% (43/102), lower density nodual in 41.9% (18/43); occasionally as heterogeneous or hyperdensity noduals or irregular border of the cervix. The features of metastatic lymph nodes in CT scan were rounded or spheroid shape of soft tissue noduals with heterogeneous density caused by central necrosis and rim enhancement.

CONCLUSIONCT scanning may be valuable in detection of > or = Ib 1 rather than < Ib 1 stage early cervical carcinoma. The additional MPR pictures of spiral CT is not only helpful in detecting tumor but also in determining the extension of cervical carcinoma.

Adenocarcinoma ; diagnostic imaging ; secondary ; Adult ; Aged ; Carcinoma, Squamous Cell ; diagnostic imaging ; secondary ; Cervix Uteri ; diagnostic imaging ; Female ; Humans ; Imaging, Three-Dimensional ; methods ; Lymph Nodes ; pathology ; Lymphatic Metastasis ; Middle Aged ; Neoplasm Invasiveness ; Neoplasm Staging ; Radiographic Image Enhancement ; Retrospective Studies ; Tomography, Spiral Computed ; methods ; standards ; Uterine Cervical Neoplasms ; diagnostic imaging ; pathology