Minwen Zheng

Low concentration contrast medium for dual-source computed tomography coronary angiography by a combination of iterative reconstruction and low-tube-voltage technique: Feasibility study

OBJECTIVES To assess the impact of low-concentration contrast medium on vascular enhancement, image quality and radiation dose of coronary CT angiography (cCTA) by using a combination of iterative reconstruction (IR) and low-tube-voltage technique. MATERIALS AND METHODS One hundred patients were prospectively randomized to two types of contrast medium and underwent prospective electrocardiogram-triggering cCTA (Definition Flash, Siemens Healthcare; collimation: 128 mm × 0.6mm; tube current: 300 mAs). Fifty patients received Iopromide 370 were scanned using the conventional tube setting (100 kVp or 120 kVp if BMI ≥ 25 kg/m(2)) and reconstructed with filtered back projection (FBP). Fifty patients received Iodixanol 270 were scanned using the low-tube-voltage (80 kVp or 100 kVp if BMI ≥ 25 kg/m(2)) technique and reconstructed with IR. CT attenuation was measured in coronary artery and other anatomical regions. Noise, image quality and radiation dose were compared. RESULTS Compared with two Iopromide 370 subgroups, Iomeprol 270 subgroups showed no significant difference in CT attenuation (576.63 ± 95.50 vs. 569.51 ± 118.93 for BMI< 25 kg/m(2), p=0.647 and 394.19 ± 68.09 vs. 383.72 ± 63.11 for BMI ≥ 25 kg/m(2), p=0.212), noise (in various anatomical regions of interest) and image quality (3.5 vs. 4.0, p=0.13), but significantly (0.41 ± 0.17 vs. 0.94 ± 0.45 for BMI< 25 kg/m(2), p<0.001 and 1.14 ± 0.24 vs. 2.37 ± 0.69 for BMI ≥ 25 kg/m(2), p<0.001) lower radiation dose, which reflects dose saving of 56.4% and 51.9%, respectively. CONCLUSIONS Combined IR with low-tube-voltage technique, a low-concentration contrast medium of 270 mg I/ml can still maintain the contrast enhancement without impairing image quality, as well as significantly lower the radiation dose.

Effect of reduced x-ray tube voltage, low iodine concentration contrast medium, and sinogram-affirmed iterative reconstruction on image quality and radiation dose at coronary CT angiography: Results of the prospective multicenter REALISE trial

BACKGROUND Both low tube voltage and sinogram-affirmed iterative reconstruction (IR) techniques hold promise to decrease radiation dose at coronary CT angiography (CCTA). The increased iodine contrast at low tube voltage allows for minimizing iodine load. OBJECTIVE To assess the effect of reduced x-ray tube voltage, low iodine concentration contrast medium and IR on image quality and radiation dose at CCTA. METHODS Two hundred thirty-one consecutive patients with suspected coronary artery disease were enrolled in this prospective, multicenter trial and randomized to 1 of 2 dual-source CCTA protocols: 120-kVp with 370 mgI/mL iopromide or iopamidol (n = 116; 44 women; 55.3 ± 9.8 years) or 100 kVp with 270 mgI/mL iodixanol (n = 115; 48 women; 54.2 ± 10.4 years). Reconstruction was performed with filtered back projection and IR. Attenuation, image noise, signal-to-noise ratio, and contrast-to-noise ratio were measured and image quality scored. Size-specific dose estimates and effective doses were calculated. RESULTS There were no significant differences in mean arterial attenuation (406.6 ± 76.7 vs 409.7 ± 65.2 Hounsfield units; P = .739), image noise (18.7 ± 3.8 vs 17.9 ± 3.4 Hounsfield units; P = .138), signal-to-noise ratio (22.5 ± 5.4 vs 23.7 ± 6.1; P = .126), contrast-to-noise ratio (17.5 ± 5.5 vs 18.3 ± 6.1; P = .286), or image quality scores (4.1 ± 0.9 vs 4.0 ± 0.9; P > .05) between 120-kVp filtered back projection-reconstructed and 100-kVp IR-reconstructed series. Mean iodine dose was 26.5% lower (18.3 ± 0.5 vs 24.9 ± 0.9 g; P < .0001), mean size-specific dose estimate was 35.1% lower (17.9 ± 6.6 vs 27.5 ± 8.2 mGy; P < .0001), and effective dose was 34.9% lower (2.3 ± 1.0 vs 3.5 ± 1.1 mSv; P < .0001) with the 100 kVp compared with the 120-kVp protocol, respectively. CONCLUSION Using low x-ray tube voltage and IR allows for decreasing the iodine load and effective radiation dose at CCTA while maintaining image quality.

Accuracy, image quality, and radiation dose of prospectively ECG-triggered high-pitch dual-source CT angiography in infants and children with complex coarctation of the aorta.

RATIONALE AND OBJECTIVES To evaluate the diagnostic accuracy, image quality, and radiation dose of prospective electrocardiogram (ECG)-triggered high-pitch dual-source computed tomography (DSCT) in infants and young children with complex coarctation of the aorta (CoA). MATERIALS AND METHODS Forty pediatric patients aged < 4 years with suspected CoA underwent prospective ECG-triggered high-pitch DSCT angiography and transthoracic echocardiography (TTE). Surgery and/or conventional cardiac angiography (CCA) were performed in all patients. The diagnostic accuracy of DSCT angiography and TTE was compared to the surgical and/or CCA findings. The causes of misdiagnosis and miss were analyzed, and the advantages and limitation of both imaging modalities were evaluated. Image quality of DSCT was evaluated, and effective radiation dose was calculated. RESULTS The sensitivity, specificity, positive predictive value, negative predictive value, and overall diagnostic accuracy of DSCT in evaluation of complex CoA were 92.37%, 98.51%, 97.32%, 93.57%, and 96.25%, respectively. There was a significant difference in the accuracy between DSCT and TTE (χ² = 9.9, P＜.05). For a total of 80 extracardiac anomalies, the sensitivity (98.8%, 79/80) of DSCT was greater than that of TTE (62.5%; 50 of 80). On the contrary, for 38 cardiac anomalies, the sensitivity (78.9%, 30 of 38) of DSCT was lesser than that of TTE (100%; 38 of 38). The mean score of image quality was 4.27 ± 0.73. The mean effective radiation dose was 0.20 ± 0.09 mSv. CONCLUSIONS Prospective ECG-triggered high-pitch DSCT may be a clinical feasible modality in the evaluation of pediatric patients with complex CoA, providing adequate image quality, high diagnostic accuracy, and low radiation dose.

Dynamic Contrast-Enhanced MR Imaging in a Phase II Study on Neoadjuvant Chemotherapy Combining Rh-Endostatin with Docetaxel and Epirubicin for Locally Advanced Breast Cancer

Background: Anti-angiogenesis is a promising therapeutic strategy for locally advanced breast cancer. We performed this phase II trial to evaluate the anti-angiogenesis and anti-tumor effect of rh-endostatin combined with docetaxel and epirubicin in patients with locally advanced breast cancer by dynamic contrast-enhanced magnetic resonance imaging in 70 previously untreated locally advanced breast cancer patients. Methods: The study population was randomly assigned to neoadjuvant chemotherapy with docetaxel and epirubicin (neoadjuvant chemotherapy group) or neoadjuvant chemotherapy combining rh-endostatin with docetaxel and epirubicin (neoadjuvant chemotherapy+rh-endostatin group). The anti-angiogenic and anti-tumor effects of both regimens were evaluated by serial dynamic contrast-enhanced magnetic resonance imaging and microvessel density measurements after final surgery. Results: The results suggested a higher clinical objective response (90.9% vs. 67.7%, P = 0.021) and greater reductions in tumor size (67.2% vs. 55.9%, P = 0.000), Ki-67 proliferation index (32.79% vs. 12.47%, P = 0.000), tumor signal enhanced ratio (64% vs. 48%, P = 0.018), and Ktrans (67% vs. 39%, P = 0.026) in neoadjuvant chemotherapy+rh-endostatin group than those in neoadjuvant chemotherapy group. In addition, the microvessel density value in the neoadjuvant chemotherapy+rh-endostatin group was significantly lower than in the neoadjuvant chemotherapy group (18.67 ± 6.53 vs. 36.05 ± 9.64, P = 0.000). Moreover, the microvessel density value was significantly correlated with Ktrans after neoadjuvant chemotherapy+rh-endostatin treatment (r=0.88, P = 0.00). Conclusions: The neoadjuvant chemotherapy+rh-endostatin treatment significantly repressed angiogenesis in locally advanced breast cancer and synergistically enhanced the anti-tumor effect of neoadjuvant chemotherapy. Serial dynamic contrast-enhanced magnetic resonance imaging data including reductions in tumor size and Ktrans, could provide non-invasive evaluation for chemotherapeutic efficacy and, consequently, optimization of individual chemotherapy for locally advanced breast cancer patients.

Spontaneous dissection of left anterior descending coronary artery: the diagnostic role of dual-source computed tomography.

Spontaneous coronary artery dissection is usually diagnosed by an urgent coronary angiography. We report a case of spontaneous coronary artery dissection of the left anterior descending coronary artery, which was diagnosed by dual-source computed tomography. Subsequent coronary angiography confirmed the result. Computed tomographic coronary angiography can be a complementary diagnostic tool for the assessment of coronary artery dissection.

[Imagings of coronary total occlusion using dual-source computed tomography].

OBJECTIVE To analyze the imaging characteristics of coronary arteries with total occlusion (TO) lesions shown by dual-source computed tomography CT (DSCT) coronary angiography. METHOD The clinical data of patients who were diagnosed as coronary heart disease together with total occlusion lesions between March 2008 and March 2010 were retrospectively analyzed. RESULTS In a cohort of 140 patients with 152 TO lesions, TO vessels in right coronary artery, left anterior descending artery, left circumflex coronary artery, or left main coronary artery were 68, 48, 20, and 1, respectively. Side branch TO were found in 15 vessels, in which 13 cases were found to be with TO in two coronary arteries. The length of TO was 5-58 mm, mean (16.8 ± 3.9) mm. TO lesions with a length ≥ 1 cm accounted for 91.4%. The appearance of stump in TO were abrupt occlusion (n=68) , blunt occlusion (n=64) , and mouse-tail occlusion (n=20) . Among all the TO lesions, 73% were soft plaque or mainly soft plaque together with minimal calcification. Mixed plaque and calcified plaque were less seen. Ten TO segments presented with dilated lumens were thrombogenesis. There were 25 TO segments angulated or tortuosity, which were most frequently shown in right coronary artery. DSCT only presented 3 TO with clear collateral vessels and no TO with bridge collateral vessels was shown. CONCLUSIONS DSCT can provide most necessary information of coronary TO lesions. Therefore, it can be used to guide surgeries on TO lesions and improve the success rates of surgeries.

Identification of CTA-Based Predictive Findings for Temporary and Permanent Neurological Dysfunction after Repair in Acute Type A Aortic Dissection

The aim of this study was to determine CT risk findings predictive of temporary neurological dysfunction (TND) and permanent neurological dysfunction (PND) after surgical repair for acute type A aortic dissection (ATAAD). A total of 255 patients (41 ± 16 years, 79% male) with ATAAD underwent aortic CT angiography (CTA) and surgical repair consecutively from January 2013 to June 2016. The CTA findings of the 255 patients for the thoracic aorta and carotid artery were analysed to identify risk factors predictive of TND and PND. Thirty-eight patients (15%) suffered TND, and 18 (7%) exhibited PND. Common carotid artery (CCA) dissection (OR = 4.63), lower enhancement of unilateral ICA (OR = 3.02) and aortic arch tears (OR = 2.83) were predictors of postoperative TND, while PND was best predicted by retrograde ascending aorta (aAO) dissection (OR = 5.62) and aortic arch tears (OR = 6.74). In CCA dissection, the extent of the entire CCA and proximal ICA (P = 0.014), a low-enhancement false lumen with re-entry (P = 0.000) and a severely narrowed true lumen without re-entry (P = 0.005) significantly increased the risk of postoperative TND. In patients with ATAAD, specific CT findings allow the individual risk of postoperative TND and PND to be identified and may guide subsequent surgical management.

The effect of without using anisodamine during CT enterography on image quality, diagnostic performance and latent side effects

OBJECTIVE To examine whether no anisodamine injection before CTE was feasible without impairing image quality and diagnostic performance. MATERIALS The change of mural thickness and luminal diameter were compared between using and no using anisodamine. The diagnostic performance of small-bowel disease was analyzed and compared. RESULTS No motion artifact was detected in two groups. There was no significant difference regarding the change of luminal diameter and mural thickness (all P>0.05). The diagnostic accuracy of small-bowel disease was no significant difference (P=0.63). CONCLUSION Lack of anisodamine injection before CTE did not impair image quality and diagnostic performance compared with CTEs performed with anisodamine injection.

Combined CT angiography of the aorta and craniocervical artery: a new imaging protocol for assessment of acute type A aortic dissection

Background To investigate the feasibility of combined computed tomography angiography (CTA) of the aorta and craniocervical artery in acute type A aortic dissection (ATAAD) and the value of incremental craniocervical information. Methods Combined CTA of head, neck and aorta was performed in patients with suspected aortic dissection and 243 ATAAD patients were analyzed. The image quality and radiation dose were assessed. Valuable craniocervical CTA findings were determined for further surgical analysis. Results The mean dose-length product (DLP) was 314.11±29.31 mGy.cm. The image quality of craniocervical arteries were 100% diagnostic. Intimal flap involving carotid arteries was detected in 47% of patients, and significant stenosis of true lumen was observed in 60% of common carotid arteries (CCAs). Hypodensity and hypoplasia/occlusion of carotid arteries were also detected and apprised surgeons. The tortuosity of carotid artery was found in 90.9% of patients. Bilateral antegrade selective cerebral perfusion (ASCP) was performed in 21.1% of aortic arch surgery based on 7 hemodynamic variation types of the circle of Willis (CW) determined by cranial CTA information. Conclusions A combined CTA of head, neck and aorta is feasible with low radiation dose and diagnostic image quality. Incremental information on craniocervical pathology and anatomy may be useful for surgery repair of ATAAD.

Renal artery to inferior vena cava fistula after nephrectomy

A 70-year-old man presented with worsening shortness of breath and lower extremity edema for 6 months. He had experienced exertional dyspnea and palpitation for 5 years. He also had a history of severe hydronephrosis with right kidney calculi, and the right kidney had been removed 28 years earlier. His blood pressure was 113/56 mm Hg, and his heart rate was 90 beats/min. A systolic rumbling murmur was audible on the apical region. Color-flow Doppler imaging showed mild mitral regurgitation, severe tricuspid regurgitation, and a shunt from the abdominal aorta to the inferior vena cava through a fistula (A, arrow). An oblique transaxial contrast-enhanced dual-source computed tomography maximum-intensity projection image (B) and the posterior view of a volume-rendered coronal projection image (C) demonstrated communication (arrows) between the descending aorta (DAO) and the inferior vena cava (IVC) via a tortuous aneurysmal vessel that seemed to arise from the right renal artery (RRA). The left renal artery (LRA) was normal, but the inferior vena cava and the left renal vein (LRV) were severely dilated. A renal artery-to-inferior vena cava fistula is a rare complication after nephrectomy. The possible cause of the fistula might have been the mass ligation of the renal pedicle, which then developed into a pseudoaneurysm. The pseudoaneurysm of the right renal artery then eroded into the inferior vena cava, resulting in a chronic arteriovenous fistula.