ABSTRACT: To reduce radiation dose for retrospective ECG-triggered helical 256-slice CTCA by determining an optimal body size index to prospectively adjust tube current.
102 consecutive patients with suspected CAD underwent retrospective ECG-triggered CTCA using 256-slice CT scanner. Six body size indexes including BMI, nipple level (NL) bust, thoracic anteroposterior diameter at NL, chest circumference (CC) at NL, left main and right coronary artery (RCA) origin level were measured and their correlation with noise was evaluated using linear regression. An equation was developed to use this index to adjust tube current. Additional 102 consecutive patients were scanned with the index-based mAs adjustment. A t-test for independent samples was used to compare radiation dose levels with and without the index-based mAs selection method.
Linear regression indicated that CC RCA had the best correlation with noise (R(2)=0.603). Effective radiation dose was reduced from 16.6±0.9 to 9.8±2.7mSv (p<0.01), i.e. 40.9% lower dose with the CC RCA-adapted tube current method. The image quality scores indicated no significant difference with and without the size-based mAs selection method.
An accessible measure of body size, such as CC RCA, can be used to adapt tube current for individualized radiation dose control.
European journal of radiology 06/2012; 81(11):3146-53. · 2.65 Impact Factor
ABSTRACT: There are a limited number of reports on the technical and clinical feasibility of prospective electrocardiogram (ECG)-gated multi-detector computed tomography (MDCT) in infants with congenital heart disease (CHD).
To evaluate image quality and radiation dose at weight-based low-dose prospectively gated 256-slice MDCT angiography in infants with CHD.
From November 2009 to February 2010, 64 consecutive infants with CHD referred for pre-operative or post-operative CT were included. All were scanned on a 256-slice MDCT system utilizing a low-dose protocol (80 kVp and 60-120 mAs depending on weight: 60 mAs for ≤ 3 kg, 80 mAs for 3.1-6 kg, 100 mAs for 6.1-10 kg, 120 mAs for 10.1-15 kg).
No serious adverse events were recorded. A total of 174 cardiac deformities, confirmed by surgery or heart catheterization, were studied. The sensitivity of MDCT for cardiac deformities was 97.1%; specificity, 99.4%; accuracy, 95.9%. The mean heart rate during scan was 136.7 ± 14.9/min (range, 91-160) with a corresponding heart rate variability of 2.8 ± 2.2/min (range, 0-8). Mean scan length was 115.3 ± 11.7 mm (range, 93.6-143.3). Mean volume CT dose index, mean dose-length product and effective dose were 2.1 ± 0.4 mGy (range, 1.5-2.8), 24.7 ± 5.9 mGy·cm (range, 14.7-35.8) and 1.6 ± 0.3 mSv (range, 1.1-2.5), respectively. Diagnostic-quality images were achieved in all cases. Satisfactory diagnostic quality for visualization of all/proximal/distal coronary artery segments was achieved in 88.4/98.8/80.0% of the scans.
Low-dose prospectively gated axial 256-slice CT angiography is a valuable tool in the routine clinical evaluation of infants with CHD, providing a comprehensive three-dimensional evaluation of the cardiac anatomy, including the coronary arteries.
Pediatric Radiology 05/2011; 41(7):858-66. · 1.67 Impact Factor
ABSTRACT: To analyze the CT/MRI features of Castleman's disease of the abdomen and pelvis.
CT/MRI images of 6 cases of pathologically confirmed Castleman's disease of the abdomen and pelvis were retrospectively reviewed. All the patients received plain CT scan and dynamic enhanced scan, and one had an additional MR scan.
One case was identified as the disseminated type with multicentric enlarged lymph nodes and hepatosplenomegaly, and 5 cases were found to have localized type, of which 3 had retroperitoneal, 1 had mesentery and 1 had pelvic lesions. On CT scan, all the 5 cases with localized lesions showed single, round or ellipse soft tissue masses, with intra-tumoral calcification in 2 cases, fascial thickening around the mass in 3 cases, and satellite nodules in 4 cases. Enhanced scanning revealed obvious enhancement in the arterial phase and continuous enhancement in the portal vein and delayed phase in all the lesions, with an attenuation pattern similar to that of large vessels; enlarged blood vessels within or around the mass were displayed in each case. In 4 cases, the intra-tumoral radial or fissured non-enhanced areas in early stage of enhancement were gradually filled up as the scan time was delayed. The patient receiving MRI showed hypo-intensity on T(1)WI and hyper-intensity on T(2)WI, presenting with an enhancement feature similar to that of CT.
Castleman's disease in the abdomen and pelvis is rare and liable to misdiagnosis, but its characteristic imaging features can help in the diagnosis and differential diagnosis.
Nan fang yi ke da xue xue bao = Journal of Southern Medical University 01/2011; 31(1):129-32.
ABSTRACT: To explore the computed tomography (CT) and magnetic resonance imaging (MRI) features of desmoid-type fibromatosis, and improve the diagnostic accuracy and understanding of the disease.
The CT and MRI features of 18 cases of surgically and pathologically confirmed desmoid-type fibromatosis were reviewed retrospectively. Among the patients, 10 received CT pre- and post-contrast scanning, and 8 patients had MRI pre- and post-contrast scanning. The CT and MRI features were analyzed in comparison with the pathological findings.
In the extraabdominal cases, the tumors occurred in the head and neck in 3, in the dorsal part of the chest in 2, in the abdominal wall and groin area in 9, and in the peritoneal cavity in 4; concomitant Gardner syndrome was found in 1 case. In 4 cases the tumor occurred within 1 to 3 years after abdominal surgeries. Pathologically, the lesion was hard and composed of fusiform fibroblasts and myofibroblast. The cells showed no obvious heteromorphism with few karyokinesis, growing invasively and recurrent locally but without distant metastasis. Immunohistochemically, the fibroblasts and myofibroblasts expressed vimentin, and the myofibroblasts were positive for SMA. On CT and MRI, the lesion appeared benign with malignant growth pattern, and caused compression of the adjacent organs and vessels or encasement of the vessels; the border was unclear without encapsulation, and necrosis and calcification was scarce. The density and signal of the tumor were well distributed. Twelve patients displayed obvious enhancement and 5 showed uneven enhancement.
The CT and MRI features of desmoid-type fibromatosis are characteristic, and CT and MRI are valuable modalities for the diagnosis and differential diagnosis of the tumor.
Nan fang yi ke da xue xue bao = Journal of Southern Medical University 11/2010; 30(11):2495-7.