mSv In Group Research Articles

Evaluation of Low-kVp Low-Volume Iodinated Contrast Protocol for Coronary CT Angiography Using Retrospective ECG Gating.

Objective The aim of this study was to evaluate the use of low peak kilovoltage (kVp) low-volume iodinated contrast protocol for performing coronary computed tomography (CT) angiography (CCTA) in patients using retrospective electrocardiogram (ECG) gating. Materials and Methods Hundred prospective patients undergoing CCTA were studied in two groups, A and B, using 70 kilovoltage (kV) and 120 kV protocols with half and standard intravenous volumes of injected iodinated contrast, respectively. All patients had heart rates less than 100 beats/min and body mass index (BMI) less than 31 kg/m 2 . Both the groups were evaluated for signal-to-noise (S/N) and contrast-to-noise (C/N) ratios along with radiation dose delivered in millisievert (mSv), and for image quality (IQ), on per patient and per segment basis. Results Patients with group A showed statistically reduced radiation dose of 1.86 mSv compared with 6.86 mSv in group B patients. Marked reduction in image noise with statistically improved S/N and C/N ratios in all coronary vessels was seen in group A. S/N ratios in group A were 20.25, 18.68, 19.04, 17.41, and 18.69 for aorta, left main, left anterior descending, right coronary, and left circumflex arteries while they were 13.34, 11.12, 10.96, 9.74, and 8.67 in group B patients. C/N ratios were also higher in all vessels in group A patients, that is, 19.48, 19.48, 19.04, 19.48, and 17.68, compared with group B patients, who had 12.43, 10.03, 9.23, 9.57, and 8.23 ratios ( p < 0.0001). No significant difference in IQ per patient and per vessel was seen between both the groups. Discussion Retrospective ECG-gated low-kVp low-volume iodinated contrast protocol provides good diagnostic quality angiograms in patients with BMI up to 31 kg/m 2 and with heart rates of less than 100 beats/min with three times reduced radiation dose. The reduced volume of contrast reduces the cost as well as the chance of contrast-induced nephropathy.

Feasibility of Ultra-Low-Dose CT for Bronchoscopy of Peripheral Lung Lesions.

Background and objectives: Thin-section computed tomography (CT) is essential for identifying small bronchi during bronchoscopy using radial endobronchial ultrasound. Some patients should receive an additional CT for a thin-section image. We performed a retrospective study with a prospectively collected database to identify the optimal radiation dose for thin-section CT during peripheral bronchoscopy. Materials and Methods: In total, 91 patients with peripheral lung lesions underwent thin-section CT (both standard CT as a reference and ultra-low-dose CT (ultra-LDCT)). The patients were randomly assigned to one of four groups according to the ultra-LDCT parameters: group 1 = 120 kVp, 25 mAs; group 2 = 100 kVp, 15 mAs; group 3 = 120 kVp, 5 mAs; and group 4 = 100 kVp, 5 mAs. Two radiologists and two physicians analyzed both the standard CT and ultra-LDCT. Results: The effective doses (EDs) of ultra-LDCT significantly differed among the four groups (median EDs were 0.88, 0.34, 0.19, and 0.12 mSv for groups 1–4, respectively; p < 0.001). Median differences in peripheral airway wall thickness were higher in group 4 than in other groups (differences in median wall thickness measured by two radiologists were 0.4–0.5 mm and 0.8–0.9 mm for groups 1–3 and group 4, respectively). Bronchus signs on ultra-LDCT in groups 1 and 2 were well correlated with those of the standard-dose CT (accuracies of two radiologists and two pulmonary physicians were 95–100%). Conclusions: Our results indicate that ultra-LDCT with ED of >0.34 mSv (ED of group 2) is feasible for peripheral bronchoscopy.

The Value of Low-dose Prospective Dual-energy Computed Tomography with Iodine Mapping in the Diagnosis of Gastric Cancer.

This study investigated the radiation dose and value of prospective dualenergy computed tomography (DECT) in the diagnosis of gastric cancer. Sixty patients scheduled for computed tomography (CT) for preoperative staging were divided into two groups. Thirty patients (Group A) underwent a single contrast-enhanced abdominal CT acquisition using a dual-source mode (100 kV/140 kV). Weighted average images of the two-kilovolt acquisitions and iodine maps were created. The remaining 30 patients underwent a standard CT scan (Group B). Two observers performed a blinded read of the images for gastric lesions, evaluating the image quality and recording effective dose. During the blinded read, observers found 90% (27/30) of the cancers in both groups. The mean imaging quality scores were 2.1±0.9 for Group A, and 2.3±1.1 for Group B. The effective mean doses were 6.59±0.59 mSv and 25.86±0.44 mSv for Groups A and B, respectively. Compared with the control group (B), the imaging quality in the low-dose group decreased a little, but the radiation dose substantially decreased by 74.6%. The new DECT technique is valuable for examining gastric cancer patients. The dualkV scan mode can substantially reduce radiation dose while preserving good diagnostic image quality.

Radiation dose and image quality of high-pitch emergency abdominal CT in obese patients using third-generation dual-source CT (DSCT)

In this third-generation dual-source CT (DSCT) study, we retrospectively investigated radiation dose and image quality of portal-venous high-pitch emergency CT in 60 patients (28 female, mean age 56 years) with a body mass index (BMI) ≥ 30 kg/m2. Patients were dichotomized in groups A (median BMI 31.5 kg/m2; n = 33) and B (36.8 kg/m2; n = 27). Volumetric CT dose index (CTDIvol), size-specific dose estimate (SSDE), dose length product (DLP) and effective dose (ED) were assessed. Contrast-to-noise ratio (CNR) and dose-independent figure-of-merit (FOM) CNR were calculated. Subjective image quality was assessed using a five-point scale. Mean values of CTDIvol, SSDE as well as normalized DLP and ED were 7.6 ± 1.8 mGy, 8.0 ± 1.8 mGy, 304 ± 74 mGy * cm and 5.2 ± 1.3 mSv for group A, and 12.6 ± 3.7 mGy, 11.0 ± 2.6 mGy, 521 ± 157 mGy * cm and 8.9 ± 2.7 mSv for group B (p < 0.001). CNR of the liver and spleen as well as each calculated FOM CNR were significantly higher in group A (p < 0.001). Subjective image quality was good in both groups. In conclusion, third-generation abdominal high-pitch emergency DSCT yields good image quality in obese patients. Radiation dose increases in patients with a BMI > 36.8 kg/m2.

Pedicle screw insertion with patient-specific 3D-printed guides based on low-dose CT scan is more accurate than free-hand technique in spine deformity patients: a prospective, randomized clinical trial.

Screw misplacement incidence can be as high as 15-30% in spine deformity surgery, with possible devastating consequences. Some technical solutions to prevent misplacement require expensive devices. MySpineTM comprises a low-dose CT scan of the patient's spine to build a virtual model of the spine to plan the screw trajectories and a 3D-printed patient-specific guide system to prepare the screw trajectories and to implant the screws in the vertebrae in order to increase reproducibility and safety of the implants. The aim of this open-label, single-center, prospective randomized clinical trial with independent evaluation of outcomes was to compare the accuracy of free-hand insertion of pedicle screws to MySpineTM 3D-printed patient-specific guides. Twenty-nine patients undergoing surgical correction for spinal deformity were randomized to Group A (pedicle screws implantation with MySpineTM) or Group B (free-hand implantation). Group A received 297 pedicle screws, and Group B 243 screws. Forty-three screws in Group A crossed over to free-hand implantation. Screw position was graded according to Gertzbein in grades 0, A, B or C, with grades 0 or A considered as "safe area." Total fluoroscopy dose and time were compared in six patients of each group. Comparing the two study groups, we observed a statistically significant difference between the two groups (p < 0.05), with 96.1% of screws in the "safe area" in Group A versus a 82.9% in Group B. Group-A patients had a mean effective dose of 0.23mSv compared to 0.82mSv in Group B. Patient-specific, 3D-printed pedicle screw guides increase safety in a wide spectrum of deformity conditions. In addition, the total radiation dose is reduced, even considering the need of a low-dose preoperative CT for surgical planning. I. These slides can be retrieved under Electronic Supplementary Material.

Safety and Efficacy of Combined Transarterial Embolization and Percutaneous Radiofrequency Ablation for Liver Tumors Using Cone-Beam CT and Needle Navigation Software in a Single Session

PurposeTo assess the safety and efficacy of single-session transarterial embolization and radiofrequency (RF) ablation for hepatic tumors with the use of needle navigation software. Materials and MethodsRetrospective analysis was conducted of 24 patients with liver cancer undergoing embolization followed by RF ablation between May 2014 and August 2017. Twelve patients each underwent (i) embolization and computed tomography (CT)–guided RF ablation during different sessions (group 1) and (ii) embolization followed by RF ablation with cone-beam CT and Needle Assist software in 1 session (group 2). Median age (70.5 y [range, 58–78 y] vs 70.5 y [range, 50–82 y]; P = .76) and performance status (0/1) were comparable between groups. Median tumor size was significantly larger in group 2 (2 cm [range, 1.0–7.3 cm] vs 3.2 cm [range, 1.1–9.6 cm]; P < .03). Procedure time, effective dose, and number of scans were examined. Efficacy was assessed by modified Response Evaluation Criteria In Solid Tumors after 1 month. Safety was assessed by Society of Interventional Radiology adverse event classification. ResultsGroup 1 had a mean of 8.5 CT scans, vs a mean of 5.0 cone-beam CT scans in group 2 (P < .001). Median procedure times were 110 min in group 1 and 199.5 min in group 2 (P < .001). Median effective doses were 68.8 mSv in group 1 and 55.4 mSv in group 2 (P = .38). There was no difference in complete response between groups (66.7% vs 63.6%; P = 1). ConclusionsTransarterial embolization followed by RF ablation with cone-beam CT and needle guidance software in a single session seems to be safe and effective.

Radiation dose and image quality in intraoperative CT (iCT) angiography of the brain with stereotactic head frames.

Intraoperative CT (iCT) angiography of the brain with stereotactic frames is an integral part of navigated neurosurgery. Validated data regarding radiation dose and image quality in these special examinations are not available. We therefore investigated two iCT protocols in this IRB-approved study. Retrospective analysis of patients, who received a cerebral stereotactic iCT angiography on a 128 slice CT scanner between February 2016 and December 2017. In group A, automated tube current modulation (ATCM; reference value 410mAs) and automated tube voltage selection (reference value 120kV) were enabled, and only examinations with a selected voltage of 120kV were included. In group B, fixed parameters were applied (300mAs, 120kV). Radiation dose was measured by assessing the volumetric CT dose index (CTDIvol), dose length product (DLP) and effective dose (ED). Signal-to-noise ratio (SNR) and image noise were assessed for objective image quality, visibility of arteries and grey-white differentiation for subjective image quality. Two hundred patients (n = 100 in each group) were included. In group A, median selected tube current was 643mAs (group B, 300mAs; p < 0.001). Median values of CTDIvol, DLP and ED were 91.54mGy, 1561mGycm and 2.97mSv in group A, and 43.15mGy, 769mGycm and 1.46mSv in group B (p < 0.001). Image quality did not significantly differ between groups (p > 0.05). ATCM yielded disproportionally high radiation dose due to substantial tube current increase at the frame level, while image quality did not improve. Thus, ATCM should preferentially be disabled. • Automated tube current modulation (ATCM) yields disproportionally high radiation dose in intraoperative CT angiography of the brain with stereotactic head frames. • ATCM does not improve overall image quality in these special examinations. • ATCM is not yet optimised for CT angiography of the brain with major extracorporeal foreign materials within the scan range.

Ultra-Low-Dose Neck CT With Low-Dose Contrast Material for Preoperative Staging of Thyroid Cancer: Image Quality and Diagnostic Performance.

Although CT has been used as a complementary diagnostic method for the preoperative diagnosis of thyroid cancer, it has the shortcomings of substantial radiation exposure and the use of contrast material (CM). The purpose of this article is to evaluate the image quality and diagnostic performance of 70-kVp thyroid CT with low volumes of CM versus conventional 120-kVp thyroid CT protocol. Eighty patients referred for preoperative thyroid CT were randomly divided into two groups (group A: 40 patients, 70 kVp, 60 mL of CM; group B: 40 patients, 120 kVp, 100 mL of CM). Quantitative and qualitative image quality and radiation doses for the two groups were compared using the Mann-Whitney U and chi-square tests. Degrees of agreement between preoperative CT staging and pathologic results were evaluated and compared using the Wald statistic. Calculated signal-to-noise ratios of different anatomic structures, calculated contrast-to-noise ratios, overall image quality, subjective noise, and streak artifacts were not significantly different between the two groups (all p > 0.05), and neither were the accuracies of preoperative CT staging (all p > 0.05). The estimated effective doses were significantly lower in group A (mean [± SD], 0.52 ± 0.14 mSv in group A and 2.28 ± 0.29 mSv in group B; p < 0.001). Ultra-low-dose 70-kVp CT with a low volume of CM provides sufficient image quality for preoperative staging of thyroid cancer and substantially reduces the radiation dose compared with standard 120-kVp CT.

The Value of 16-cm Wide-Detector Computed Tomography in Coronary Computed Tomography Angiography for Patients With High Heart Rate Variability.

The aim of this study was to investigate radiation dose and image quality of coronary computed tomography (CT) angiography (CCTA) for patients with high heart rate variability (HRv) using 16-cm wide-detector CT scanner. One hundred sixty-six patients with uncontrolled heart rate underwent CCTA on a 16-cm wide-detector CT system and were divided into 2 groups based on their HRv for analysis: group A (n = 95, HRv ≤10 beats/min [bpm]) and group B (n = 71, HRv >10 bpm). Images in both groups were reconstructed with motion correction algorithm. Subjective and objective image qualities were analyzed. There were no significant differences in age, body mass index, and heart rate (68.1 ± 11.4 vs 67.6 ± 12.3 bpm) between the 2 groups (P > 0.05). However, group B had significantly higher HRv than group A (33.5 ± 24.4 vs 7.8 ± 1.2 bpm, P < 0.001). All images were acceptable for clinical diagnosis. Compared with group A, image quality scores in group B decreased slightly (4.1 ± 0.5 vs 4.0 ± 0.6). However, the difference was not statistically significant. The mean effective doses were both relatively low at 2.2 ± 1.1 mSv in group A and 2.6 ± 1.4 mSv in group B. Single-heartbeat free-breathing CCTA can be performed for patients with high HRv using 16-cm wide-detector CT scanner to achieve diagnostic image quality with low radiation dose.

Concentric Stereotactic Technique of Percutaneous Endoscopic Transforaminal Discectomy and Radiation Exposure to Surgeons

In percutaneous endoscopic transforaminal discectomy (PETD), surgeons are exposed to intraoperative radiographic radiation over a long-term career, which may be correlated with high risk of iatrogenic radiation hazards. The purpose of this prospective cohort study was to assess the impact of concentric stereotactic technique on radiation exposure to surgeons in PETD. Patients who underwent conventional PETD were regarded as group A, whereas those undergoing PETD with concentric stereotactic technique were considered as group B. The primary outcomes were cumulative radiation dose to the surgeon's eye, thyroid gland, and breast. A total of 34 patients were treated in group A and 30 patients were treated in group B. The cumulative radiation dose of the eye per operation was 0.017 (0.58/34) mSv in group A and 0.010 (0.31/30) mSv in group B, which meant a reduction of 41.18%. The cumulative radiation dose of the thyroid gland per operation was 0.018 (0.60/34) mSv in group A and 0.011 (0.33/30) mSv in group B, which meant a reduction of 38.89%. The cumulative radiation dose of the chest per operation was 0.039 (1.33/34) mSv in group A and 0.023 (0.70/30) mSv in group B, which meant a reduction of 41.03%. There were no significant differences in hospital stay, visual analog scale score of waist and leg pain, Oswestry Disability Index score, MacNab satisfaction, and complications between the 2 groups (P > 0.05). The concentric stereotactic technique can effectively reduce radiation exposure to surgeons by about 40%.

Low-dose paediatric cardiac and thoracic computed tomography with prospective triggering: Is it possible at any heart rate?

ObjectiveTo demonstrate that the use of step-and-shoot (SAS) mode in paediatric cardiac CT angiography (CCTA) is possible at heart rates (HR) greater than 65 bpm, allowing low-dose acquisition with single-source 64-slices CT. MethodsWe retrospectively included 125 paediatric patients (0–6 years). CCTA was performed with SAS at diastolic phase in 31 patients (group D, HR < 65 bpm), at systolic phase in 45 patients (group S, HR ≥ 65 bpm) and with non-gated mode in 49 patients (group NG). Effective dose (ED) and image quality using a 3-grade scoring scale (1, excellent; 2, moderate; 3, insufficient) of group S were compared with group D for coronary examinations and group NG for entire thorax vascular anatomy. ResultsFor coronary indications, median ED was 0.6 mSv in group D versus 0.9 mSv in group S (p < 0.01). For whole thorax indications, median ED was 2.7 mSv in group NG versus 1.1 mSv in group S (p < 0.001). The mean image quality score was (1.4 ± 0.6) points in group D, (1.4 ± 0.7) in group S for coronary indications (p = 0.9), (1.3 ± 0.6) in group S for whole thorax indications and (2.0 ± 0.0) in group NG (p < 0.001). ConclusionSAS mode is feasible in children with HR greater than 65 bpm allowing low-dose CCTA. It provided comparable image quality in systole, compared to diastole. SAS at the systolic phase provided better image quality with less radiation dose compared to non-gated scans for whole thorax examinations.

Subtraction CT angiography in head and neck with low radiation and contrast dose dual-energy spectral CT using rapid kV-switching technique.

To investigate the application of low radiation and contrast dose spectral CT angiology using rapid kV-switching technique in the head and neck with subtraction method for bone removal. This prospective study was approved by the local ethics committee.64 cases for head and neck CT angiology were randomly divided into Groups A (n = 32) and B (n = 32). Group A underwent unenhanced CT with 100kVp, 200mA and contrast-enhanced CT with spectral CT mode with body mass index-dependent low dose protocols. Group B used conventional helical scanning with 120kVp, auto mA for noise index of 12HU (Hounsfield unit)for both the unenhanced and contrast-enhanced CT. Subtraction images were formed by subtracting the unenhanced images from enhanced images (with the 65keV-enhanced spectral CT image in Group A). CT numbers and their standard deviations in aortic arch, carotid arteries, middle cerebral artery and air were measured in the subtraction images. The signal-to-noise ratio and contrast-to-noise ratio for the common and internal carotid arteries and middle cerebral artery were calculated. Image quality in terms of bone removal effect was evaluated by two experienced radiologists independently and blindly using a 4-point system. Radiation dose and total iodine load were recorded. Measurements were statistically compared between the two groups. The two groups had same demographic results. There was no difference in the CT number, signal-to-noise and contrast-to-noise ratio values for carotid arteries and middle cerebral artery in the subtraction images between the two groups (p > 0.05). However, the bone removal effect score [median (min-max)] in Group A [4 (3-4)] was rated better than in Group B [3 (2-4)] (p < 0.001), with excellent agreement between the two observers (κ>0.80). The radiation dose in Group A (average of 2.64 mSv) was 57% lower than the 6.18 mSv in Group B (p < 0.001). The total iodine intake in Group A was 13.5g, 36% lower than the 21g in Group B. Spectral CT imaging with rapid kV-switching in the subtraction angiography in head and neck provides better bone removal with significantly reduced radiation and contrast dose compared with conventional subtraction method. Advances in knowledge: This novel method provides better bone removal with significant radiation and contrast dose reduction compared with the conventional subtraction CT, and maybe used clinically to protect the thyroid gland and ocular lenses from unnecessary high radiation.

Image quality and radiation dose of coronary CT angiography performed with whole-heart coverage CT scanner with intra-cycle motion correction algorithm in patients with atrial fibrillation.

To evaluate image quality, coronary evaluability and radiation exposure of coronary CT angiography (CCTA) performed with whole-heart coverage cardiac-CT in patients with atrial fibrillation (AF). We prospectively enrolled 164 patients with AF who underwent a clinically indicated CCTA with a 16-cm z-axis coverage scanner. In all patients CCTA was performed using prospective ECG-triggering with targeted RR interval. We evaluated image quality, coronary evaluability and effective dose (ED). Patients were divided in two subgroups based on heart rate (HR) during imaging. Group 1: 64 patients with low HR (<75 bpm), group 2: 100 patients with high HR (≥75 bpm). Written informed consent was obtained from all patients and the institutional ethics committee approved the study protocol. In a segment-based analysis, coronary evaluability was 98.4 % (2,577/2,620 segments) in the whole population, without significant differences between groups (1,013/1,024 (98.9 %) and 1,565/1,596 (98.1 %), for groups 1 and 2, respectively, p=0.15). Mean ED was similar in both groups (3.8±1.9 mSv and 3.9±2.1 mSv in groups 1 and 2, respectively, p=0.75) CONCLUSIONS: The whole-heart-coverage scanner could evaluate coronary arteries with high image quality and without increase in radiation exposure in AF patients, even in the high HR group. • Last-generation CT scanner improves coronary artery assessment in AF patients. • The new CT scanner enables low radiation exposure in AF patients. • Diagnostic ICA maybe avoided in AF patients with suspected CAD. • Whole-heart coverage CT scanner enables low radiation exposure in AF patients.

Feasibility of high-pitch spiral dual-source CT angiography in children with complex congenital heart disease compared to retrospective-gated spiral acquisition

To investigate the use of second-generation dual-source high-pitch computed tomography in obtaining confident diagnostic image quality using a low radiation dose in young patients with congenital heart disease (CHD). From July 2014 to June 2016, 50 consecutive children <4 years with complex CHD underwent electrocardiography (ECG)-triggered dual-source computed tomography (CT). The patients were assigned randomly to two groups: high-pitch (pitch 3.4) spiral dual-source CT acquisition (group A) and retrospectively spiral dual-source CT acquisition (group B). The image quality, diagnostic accuracy, coronary artery origin, course demonstration, and radiation exposure were compared between the two groups. Fifty examinations were performed (group A, 25; group B, 25). There were no significant differences in image quality, diagnostic accuracy, coronary artery origin, and course demonstration between the two groups. The image quality scores were 1.3±0.4 in group A and 1.1±0.3 in group B (p=0.2). The diagnostic accuracy was 100% in both groups. The coronary arteries were traceable in 80% in group A and 84% in group B (p=0.7). A single coronary artery was identified in one case in group A and the left anterior descending (LAD) branch originated from the right coronary artery (RCA) in one case in group B. There were significant differences in the effective doses between the two groups (0.40±0.20mSv in group A and 2.7±1.0mSv in group B, p<0.05). Intra-cardiac and extra-cardiac malformation, coronary artery origin, and course malformation can be visualised clearly using a high-pitch ECG-triggered dual-source CT with a low radiation dose and good image quality in patients with CHD.

Non-Electrocardiogram-Triggered 70-kVp High-Pitch Computed Tomography Angiography of the Whole Aorta With Iterative Reconstruction: Initial Results.

To evaluate the feasibility of non-electrocardiogram (ECG)-triggered 70-kVp high-pitch aortic computed tomography angiography (CTA) with iterative reconstruction (IR) and reduced contrast agent using second-generation dual-source CT (DSCT). Seventy-seven patients were examined: group A (n = 21), 70-kVp high-pitch (3.2) CTA, 60 mL contrast agent and IR on second-generation DSCT; group B (n = 29), standard-pitch (1.2) CTA, automatic tube voltage selection, filtered back projection and 80 mL contrast agent on second-generation DSCT; group C (n = 27), 120-kVp standard-pitch (1.2) CTA, filtered back projection, and 80 mL contrast agent on first-generation DSCT. Computed tomography values, noise, signal-to-noise ratio, contrast-to-noise ratio, and subjective image quality were compared. Computed tomography values and noise of all aortic segments in group A were increased compared with groups B and C (P < 0.05). Group B showed the highest signal-to-noise ratio and contrast-to-noise ratio for all aortic segments (P < 0.05), whereas no significant differences were found between groups A and C (P > 0.05). Mean effective dose was 0.88 ± 0.08 mSv for group A, reduced by 93% compared to group C and by 90% compared to group B. Non-ECG-triggered 70-kVp high-pitch aortic CTA with IR provides equivalent diagnostic image quality with 90% reduction of radiation dose and 25% reduction of contrast volume compared with standard 120-kVp CTA.

Coronary CT angiography in obese patients using 3(rd) generation dual-source CT: effect of body mass index on image quality.

To evaluate the image quality of coronary CT angiography (CCTA) in obese patients using a 3(rd) generation, dual-source CT scanner. We retrospectively evaluated 102 overweight and obese patients who had undergone CCTA. Studies were performed with 3(rd) generation dual-source CT, prospectively ECG-triggered acquisition at 120kV, and automated tube current modulation. Advanced modeled iterative reconstruction was used. Patients were divided into three BMI groups: 1)25-29.9kg/m(2); 2)30-39.9kg/m(2); 3) ≥ 40kg/m(2). Vascular attenuation in the coronary arteries was measured. Contrast-to-noise ratio (CNR) was calculated. Image quality was subjectively evaluated using five-point scales. Image quality was considered diagnostic in 97.6% of examinations. CNR was consistently adequate in all groups but decreased for groups 2 and 3 in comparison to group 1 as well as for group 3 compared to group 2 (p = 0.001, respectively). Subjective image quality was significantly higher in group 1 compared to group 3 (attenuation proximal: 4.8 ± 0.4 vs. 4.4 ± 0.6, p = 0.011; attenuation distal: 4.5 ± 0.7 vs. 4.0 ± 0.8, p = 0.019; noise: 4.7 ± 0.6 vs. 3.8 ± 0.7, p < 0.001). The mean effective dose was 9.5 ± 3.9mSv for group 1, 11.4 ± 4.7mSv for group 2 and 14.0 ± 6.4mSv for group 3. Diagnostic image quality can be routinely obtained at CCTA in obese patients with 3(rd) generation DSCT at 120kV. • Diagnostic CCTA can be routinely performed in obese patients with 3 (rd) generation DSCT. • 120-kV tube voltage allows diagnostic image quality in patients with BMI > 40kg/m (2) . • 80-ml contrast medium can be administered without significant decline in vascular attenuation.

Interest of intra-operative 3D imaging in spine surgery: a prospective randomized study.

We report a single-center, prospective, randomized study for pedicle screw insertion in opened and percutaneous spine surgeries, using a computer-assisted surgery (CAS) technique with three-dimensional (3D) intra-operative images intensifier (without planification on pre-operative CT scan) vs conventional surgical procedure. We included 143 patients: Group C (conventional, 72 patients) and Group N (3D Fluoronavigation, 71 patients). We measured the pedicle screw running time, and surgeon's radiation exposure. All pedicle runs were assessed according to Heary by two independent radiologists on a post-operative CT scan. 3D Fluoronavigation appeared less accuratein percutaneous procedures (24% of misplaced pedicle screws vs 5% in Group C) (p=0.007), but more accurate in opened surgeries (5% of misplaced pedicle screws vs 17% in Group C) (p=0.025). For one vertebra, the average surgical running time reached 8min in Group C vs 21min in Group N for percutaneous surgeries (p=3.42×10(-9)), 7.33min in Group C vs 16.33min in Group N (p=2.88×10(-7)) for opened surgeries. The 3D navigation device delivered less radiation in percutaneous procedures [0.6 vs 1.62mSv in Group C (p=2.45×10(-9))]. For opened surgeries, it was twice higher in Group N with 0.21 vs 0.1mSv in Group C (p=0.022). The rate of misplaced pedicle screws with conventional techniques was nearly the same as most papers and a little bit higher with CAS. Surgical running time and radiation exposure were consistent with many studies. Our work hypothesis is partially confirmed, depending on the type of surgery (opened or closed procedure).

The Feasibility of Combined Coronary and Supra-aortic Arteries CT Angiography with a Single High-pitch Acquisition Protocol using Dualsource CT

Objectives: To compare the image quality and radiation dose of combined coronary and supra-aortic arteries CT angiography (CTA) with a one stop shop single high-pitch acquisition protocol to that of separately acquisition protocol. Materials and methods: This study screened 211 consecutively symptomatic patients who were suspected coronary artery disease and/or cerebrovascular diseases and a total of 164 patients were included in this study. Each group of 82 patients were randomly assigned in a 1:1 fashion to one of high-pitch combined coronary and supra-aortic arteries CTA acquisition protocol (group A) or separately acquisition protocol using high-pitch mode coronary CTA and Dual-energy mode carotid-cerebrovascular CTA (group B). The objective image quality including the enhancement values, image noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of coronary and supra-aortic arteries were measured and calculated. The subjective image quality was evaluated according to the image quality scores. Results: The average enhancement and image noise of supra-aortic arteries in group A were significantly higher than that of group B. The SNR and CNR measurements in the intra-cranial and extra-cranial carotid arteries did not show a statistically significant difference (all P>0.05). No significant difference was found for the mean image quality score either in coronary arteries or in the intra-cranial and extra-cranial carotid arteries between the two groups with regard to each score rate. The effective radiation dose was 1.36 ± 0.37 mSv in group A and 2.39 ± 0.38 mSv in group B (P<0.01). Conclusion: The results of our study indicate that the combined coronary and supra-aortic arteries CTA with a one stop shop single high-pitch acquisition protocol provides a high image quality and success ratio along with significant reduction of radiation exposure and less contrast material, compared to that of separately acquisition protocol.

Performances diagnostiques des tomoscintigraphies myocardiques de stress, réalisées avec une caméra à semi-conducteurs et un protocole très faible dose

IntroductionThis retrospective study aimed to assess the performances in the detection of coronary artery disease patients of the stress myocardial perfusion imaging (MPI) performed with a semiconductor camera, a very low dose stress-rest protocol and short recording times. Material and methodsWe analyzed consecutive MPI exams, which has been routinely planed with the “D-SPECT” semiconductor camera, a 1-day stress-rest protocol, very low doses of Sestamibi-99mTc (120MBq at stress and 360MBq at rest for a 75kg body weight patient) and short acquisition-times targeting the recording of 500 myocardial kcounts (on average, 8min for stress and 3min for rest). The ability to detect coronary artery stenosis (>50% diameter reduction) was assessed in a group of 118 patients, who had coronary angiography at ≤3months from MPI, and normalcy rate was assessed in a group of 74 patients showing a low pretest probability of coronary artery disease (<10%). ResultsSensitivity, positive predictive value and global accuracy for identifying the 81 patients with ≥1 coronary artery stenosis were 85%, 83% and 78%, respectively; and normalcy rate was 96%. Mean effective doses were: (1) 4.9±1.4mSv in the group with coronary angiography and where most exams (90%) comprised both stress and rest MPI; and (2) 1.9±1.5mSv in the low probability group and where most exams (70%) comprised only stress MPI. ConclusionWhen performed with a sensitive semiconductor camera and a very low dose stress-rest protocol, MPI provides high diagnostic performances, equivalent to those documented with conventional cameras in the same study setting, but with dramatic reduction of patients’ radiation.

Electrodiagnostic evaluation of patients with carpal tunnel syndrome regarding the presence of subjective and physical findings

Aim of our study was to evaluate the changes of median nerve conduction velocities by electrodiagnostic procedure in carpal tunnel syndrome (CTS) patients with and without present subjective and physical findings. We have evaluated 116 patients that were diagnosis with CTS. Subjective findings: weakness, numbness and night pain were analyzed. Further physical findings were evaluated: Tinels sign, muscles hypotrophy and weakness according to muscle manual test (MMT). Duration of complaints was evaluated as well. Electroneurographic findings included: estimation of median nerve motor terminal latency (mMTL), sensory velocity (mSV) and motor velocity (mMV). Significantly longer complaints were present in patients who experienced night pain (p=0.015) and those with muscles weakness on MMT (p=0.016). Statistically significant increase for mMTL values was noticed for patients with Tinels sign (p&lt;0.045), present muscles hypotrophy (p&lt;0.001) and weakness on MMT (p&lt;0.001). There is significant decrease for mMV in group with present Tinels sign (p=0.048), muscle hypotrophy (p=0.003) and weakness on MMT (p=0.002), and for mSV in group with present muscle hypotrophy (p=0.008) and group with weakness on MMT (p=0.019). Multivariate logistic regressional analysis shown that only for hypotrophy, mMTL variable presents significant independent contributor (p=0.009). For the diagnosis confirmation and treatment planning along with elecroneurography it is necessary to evaluate patients with CTS clinically, since different clinical manifestations are correlating in different degree with electroneurographic findings.