First Clinical Evaluation of High-Pitch Dual-Source Computed Tomographic Angiography Comparing Automated Tube Potential Selection With Automated Tube Current Modulation.

OBJECTIVE: To investigate and compare the use of automated tube potential selection (ATPS) with automated tube current modulation (ATCM) in high-pitch dual-source computed tomographic angiography (CTA) for imaging the whole aorta without electrocardiogram synchronization. METHODS: Two groups of 60 patients underwent CTA on a dual-source computed tomographic device in high-pitch mode: ATCM (with 100-kV fixed tube potential) was used in group 1 and ATPS (with the same image quality options) in group 2. For the evaluation of radiation exposure, CT dose index and dose-length product were analyzed. Contrast and image quality were assessed by 2 independent observers. RESULTS: The ATPS group received a higher radiation dose than the ATCM group (P < 0.001) because in 80% of patients, the software switched to use of a 120-kV tube potential. In all cases, images of the aorta were of sufficient quality. CONCLUSIONS: High-pitch dual-source CTA of the aorta using ATPS is feasible in clinical routine, but is associated with higher radiation exposure than the ATCM protocol. This finding contradicts previously evaluations of ATPS based on single-source techniques.

70 kV computed tomography of the thorax: valence for computer-assisted nodule evaluation and radiation dose - first clinical results.

BACKGROUND: Computed tomography (CT) is the gold standard for evaluation of pulmonary nodules and is at the same time responsible for the majority of the collective effective dose. PURPOSE: To evaluate radiation dose and efficacy of computer-assisted detection (CAD) for solid pulmonary nodules in low dose chest CT performed at 70 kV. MATERIAL AND METHODS: CAD was performed upon chest CT with 70 kV and 100 kV (gold standard) at manufacture's recommended tube current of 87 mAs (collimation, 64 × 0.6 mm). Detection rate for pulmonary nodules and size measurements of both techniques were compared to each other. Radiation dosage in terms of effective dose (E) was measured using an Alderson-Rando Phantom. RESULTS: Seventy-four patients with 301 solid nodules were included in the study. CAD detection rate was similar for 70 kV (94.7%) and 100 kV (92.4%). Mean transversal nodule diameter was 5.5 mm for 70 kV and 5.7 mm for 100 kV with an average volume of 0.12 mL (both techniques). Derived from the phantom measurements patient examinations resulted in an E of 0.51 mSv (70 kV) versus 2.02 mSv (100 kV). CONCLUSION: 70 kV low-dose chest CT is suitable for CAD based lung nodule analysis at a fraction of the radiation burden of the standard technique. Since the measurements are highly accurate, 70 kV CT could be used for detection of pulmonal lesions as well as follow-up studies.

Comparative study between mobile computed radiography and mobile flat-panel radiography for bedside chest radiography: impact of an antiscatter grid on the visibility of selected diagnostically relevant structures.

OBJECTIVES: The objective of this study was to evaluate the diagnostic performance of 2 different imaging systems in adult bedside chest radiography and the impact on the visibility of selected diagnostically relevant structures in the images acquired with these systems, with and without an antiscatter grid. MATERIALS AND METHODS: We acquired bedside chest radiographs of 103 intensive-care patients (36 women, 67 men; age range, 17-90 years; mean age, 66.4 years) using 4 acquisition techniques (computed radiography [CR] and digital radiography [DR], with and without grid). Image quality was evaluated independently by 4 radiologists using a 9-point visibility scale. Evaluated were lung parenchyma, soft tissues, thoracic spine, foreign bodies, and the overall image quality. Interobserver agreement and differences between the systems were tested using an interclass correlation (ICC) test. Mean scores were compared using the analysis of variance, followed by the post hoc pairwise testing (the Tukey test) in case of multiple group comparisons and by the Student t test in case of single group comparisons (P < 0.05, significant). RESULTS: The image quality of the structures evaluated in the DR images with a grid was significantly higher than that obtained without a grid (P < 0.001) for all structures. The use of a grid in CR significantly improved the overall image quality, lung parenchyma, and soft tissue delineation (P < 0.001). Foreign body delineation, however, was significantly better in the CR images obtained without a grid (P < 0.001), whereas the 2 systems showed no significant difference regarding thoracic spine delineation (P = 0.554). The scores of the DR images were significantly higher than those of the CR images for all structures. The interobserver agreement was substantial for lung parenchyma (ICC, 0.77), soft tissue (ICC, 0.78), thoracic spine (ICC, 0.80), and the overall image quality (ICC, 0.78) and was almost perfect for foreign bodies (ICC, 0.81). CONCLUSIONS: The use of an antiscatter grid significantly improved the image quality of bedside DR radiographs. A similar effect was seen with CR radiographs but only for lung parenchyma, soft tissue, and the overall image quality. Mobile DR outperformed CR in all structures.

Analysis of disk volume before and after CT-guided intradiscal and periganglionic ozone-oxygen injection for the treatment of lumbar disk herniation.

PURPOSE: To quantify the change in volume in herniated lumbar disk after computed tomography (CT)-guided intradiscal and periganglionic ozone-oxygen injection and to assess the effects of patient age, sex, and initial disk volume on disk volume changes. MATERIALS AND METHODS: A total of 283 patients with lumbar radiculopathy received a single intradiscal (3 mL) and periganglionic (7 mL) injection of an ozone-oxygen mixture (ratio, 3:97; ozone concentration, 30 µg/mL). Under CT guidance, intradiscal and periganglionic injection was performed through an extraspinal lateral approach with a 22-gauge spinal needle. All disk volume changes were evaluated on CT 6 months after the procedure in all patients. RESULTS: Initial mean disk volume was 17.37 cm(3) ± 4.70 (standard deviation; range, 8.12-29.15 cm(3)). Disk volume reduction (mean, 7.70% ± 5.45; range, 0.29%-22.31%) was seen in 96.1% of treated disks (n = 272) at 6 months after treatment and was found to be statistically significant (P < .0001). In 3.9% of patients (n = 11), disk volume increased (mean, 0.59% ± 0.24; range, 0.11%-0.81%). Patient age correlated negatively with disk volume reduction (r = -0.505; P < .0001) at 6 months after treatment, whereas initial disk volume correlated positively with volume reduction (r = 0.225; P = .00014) after therapy. No correlation was noted between patient sex and disk volume reduction after treatment (P = .09). CONCLUSIONS: Intradiscal administration of medical ozone is associated with a statistically significant volume reduction of the herniated lumbar disk. The volume-reduction effect of ozone correlates negatively with the patient's age and positively with initial disk volume.

High-pitch dual-source computed tomography pulmonary angiography in freely breathing patients.

PURPOSE: To investigate pulmonary arterial (PA) enhancement, image noise, and artifacts related to breathing and heart motion in patients with suspected pulmonary embolism. MATERIALS AND METHODS: Seventy-six consecutive patients underwent computed tomographic pulmonary angiography (CTPA) in dual-source high-pitch mode (pitch 3.0, 100 kV, 180 mAs, 50 mL contrast material) without breathing commands. PA enhancement, image noise, signal to noise ratio, overall image quality, incidence of total or partial interruption of the contrast column in the PAs, and heart motion-related and breathing-related artifacts of the diaphragm and pulmonary structures were recorded. RESULTS: Mean central and peripheral PA attenuation was 404 ± 104 and 453 ± 119 HU; mean image noise was 11 ± 2 HU; mean examination time was 0.67 ± 0.09 s; and mean dose-length product was 142 ± 31 mGy cm. There were no motion artifacts of the diaphragm or pulmonary vessels related to breathing or heart motion. There was no case of partial or total interruption of the contrast column in the PA tree. No examination was rated nondiagnostic. CONCLUSIONS: High-pitch dual-source CTPA in freely breathing patients effectively produces images that are free of artifacts related to breathing and cardiac motion. Hence, Valsalva-related artifacts can be eliminated using this technique.

High-pitch dual-source CT angiography of the whole aorta without ECG synchronisation: initial experience.

OBJECTIVE: To investigate the feasibility, image quality and radiation dose for high-pitch dual-source CT angiography (CTA) of the whole aorta without ECG synchronisation. METHODS: Each group of 40 patients underwent CTA either on a 16-slice (group 1) or dual-source CT device with conventional single-source (group 2) or high-pitch mode with a pitch of 3.0 (group 3). The presence of motion or stair-step artefacts of the thoracic aorta was independently assessed by two readers. RESULTS: Subjective and objective scoring of motion and artefacts were significantly reduced in the high-pitch examination protocol (p < 0.05). The imaging length was not significantly different, but the imaging time was significantly (p < 0.001) shorter in the high-pitch group (12.2 vs. 7.4 vs. 1.7 s for groups 1, 2 and 3). The ascending aorta and the coronary ostia were reliably evaluable in all patients of group 3 without motion artefacts as well. CONCLUSION: High-pitch dual-source CT angiography of the whole aorta is feasible in unselected patients. As a significant advantage over regular pitch protocols, motion-free imaging of the aorta is possible without ECG synchronisation. Thus, this CT mode bears potential to become a standard CT protocol before trans-catheter aortic valve implantation (TAVI).

64-slice multidetector-row computed tomography in the diagnosis of coronary artery disease: interobserver agreement among radiologists with varied levels of experience on a per-patient and per-segment basis.

PURPOSE: To assess the interobserver variability of 4 radiologists with different levels of experience in the evaluation of 64-slice coronary computed tomographic angiography (cCTA). MATERIALS AND METHODS: Two board-certified radiologists with 10 and 8 years of experience in reading cCTA and 2 radiology residents, 1 with 3 years of experience in reading cCTA and 1 with experience in reading general computed tomographic scans but without dedicated cCTA training, participated in the study. All the observers independently analyzed 50 cCTA studies for signs of coronary artery disease (stenosis of 0%, ≤49%, 50% to 74%, 75% to 99%, or 100%). Diagnostic accuracy of the 4 readers for stenosis detection on cCTA was compared with that of conventional angiography on a per-segment and per-patient basis. No patients, vessels, or segments were excluded from analysis. RESULTS: On a per-segment basis, correlation between cCTA and invasive coronary angiography was good for readers with more than 10 (r=0.75), more than 8 (r=0.75), and more than 3 (r=0.73) years of cCTA experience. The correlation coefficient was poor (r=0.39) for the untrained reader. Sensitivity was not significantly (P=0.56) different between observers with more than 8 and more than 10 years of experience but was significantly (P>0.05) lower for the reader with less than 3 years experience and for the untrained reader. However, we found no significant difference in overall diagnostic accuracy on a per-patient (P=0.86) and on a per-segment level (P=0.72) among the 4 readers. CONCLUSION: The level of experience significantly influences the sensitivity of coronary artery stenosis detection at cCTA, and thus highlights the need for dedicated training in cCTA interpretation.

Dose and image quality at CT pulmonary angiography-comparison of first and second generation dual-energy CT and 64-slice CT.

OBJECTIVE: To compare dose and image quality of 64-slice, first and second generation dual-energy CT (DECT) for CT pulmonary angiography (CTPA). METHODS: Totally 120 patients, 30 in each group, underwent CTPA on a first generation (group 1: single-energy, 120 kV/145 mAs; group 2: DE, 140/80 kV, 70/350 mAs) or second generation dual-source DECT device (group 3: DE, 100/Sn140 kV, 120/102 mAs; group 4: DE, 80/Sn140 kV, 202/86 mAs). CTDIvol, DLP, background noise (BN), thorax diameter and attenuation in the pulmonary trunk were compared. RESULTS: Thorax diameter and attenuation in the pulmonary trunk did not differ significantly (p > 0.4 and >0.19) between the groups. Mean CTDIvol and DLP were significantly lower (p < 0.003) in group 4 (6.2 ± 1.6 mGy/170 ± 41 mGycm) compared to group 1 (8.5 ± 2.6 mGy/235 ± 117 mGycm), group 2 (9.2 ± 3.3 mGy/224 ± 122 mGycm) and group 3 (8.7 ± 2.8 mGy/246 ± 86 mGycm). BN was significantly lower (p < 0.0001) in group 4 (12 ± 3 HU) and group 1 (13 ± 6 HU) compared to group 3 and 2 (16 ± 6 HU and 23 ± 9). CONCLUSION: The use of second generation DECT in 80/Sn140 kV configuration allows for significant dose reduction with image quality similar to 120 kV CTPA.

Reconstruction of a mandibular defect with autogenous, autoclaved bone grafts and tissue engineering: An in vivo pilot study.

Reconstruction of bone defects with autogenous, autoclaved bone grafts has already been described but does have one major insuperable problem-the loss of the ostoinductive potential of the graft. In this study, we investigated if autogenous, autoclaved grafts in combination with tissue engineered bone can overcome this problem. An en-bloc resection was done in the mandible of eight pigs. The grafts were autoclaved and filled with autogenous, osseogen differentiated bone marrow cells and compared with four animals without bone marrow cells. After 120 days, the specimens were qualitatively and quantitatively evaluated by means of microradiography and light microscopy. Within the experimental group, osseous remodeling was detected in all cases and new bone formation was visible. Quantitative assessment of the osseous bridging of the osteotomy sites was significantly higher in the test group in comparison with the control group (p = 0.03). The histological evaluation by means of an osseous integration of the grafts revealed a statistically significant difference between both groups as well (p = 0.01). The results of this study indicate that the method investigated hereby represents a further possibility in the therapy of bony defects, such as those arising as a result of tumor operations.

Value of cerebral perfusion computed tomography in the management of intensive care unit patients with suspected ischaemic cerebral pathology after cardiac surgery.

OBJECTIVE: Adverse neurologic outcomes, like stroke, in intensive care unit (ICU) patients after cardiac surgery can have devastating consequences, among them increased mortality risk and, among survivors, loss of independence and a diminished quality of life. Non-contrast computed tomography (CT) remains a widely utilised modality for assessing stroke; however, it has a low sensitivity in the acute phase. Perfusion CT (PCT) has the potential of imaging stroke in its hyperacute phase. We evaluated the feasibility and results of the method among patients from the ICU. METHODS: The NCCT and PCT images of 33 retrospectively identified patients were included in this study. The diagnostic contribution of the PCT to patient management was classified according to one of three categories: (A) those that changed the preliminary (NCCT) diagnosis; (B) those that revealed additional pathology and/or specified more exactly findings that have been detected by NCCT or clinically suspected; and (C) confirmed the preliminary diagnosis. Neurologic outcome variables were also documented and associated with PCT lesions. RESULTS: Fifteen patients after coronary artery bypass graft (CABG) operation, 14 patients after CABG and valve surgery, and 4 patients after an aortic dissection (Type A) surgery underwent a NCCT with PCT 2.4+/-1.3 days after the operation. Twenty patients had bilateral internal carotid artery (ICA) stenosis (>50%), 11 patients had unilateral ICA stenosis (>75%), and 2 patients had no ICA stenosis. In nine patients (27.2%) the PCT changed the initial diagnosis of the NCCT and revealed ischaemic pathology. In 24 patients (72.7%), the performed PCT revealed additional pathology and/or more completely characterised findings that have been detected by the initial NCCT. In nine patients, PCT confirmed only the initial diagnosis. Patients with normal PCT findings had a favourable outcome; patients with large lesions in PCT in one or more vascular territories had an unfavourable outcome; seven patients with lesions in basal ganglia and/or semioval centre had a favourable outcome. CONCLUSIONS: PCT shows a greater sensitivity in detecting and mapping acute ischaemic stroke in ICU patients (after cardiac surgery) in whom conventional imaging findings are not in line with the severity of the clinical condition.

Coronary CTA: image acquisition and interpretation.

Computed tomography (CT) of the heart, because of ongoing technical refinement and intense scientific and clinical evaluation, has left the research realm and has matured into a clinical application that is about to fulfill its promise to replace invasive cardiac catheterization in some patient populations. By nature of its target, the continuously moving heart, CT coronary angiography is technically more challenging than other CT applications. Also, rapid technical development requires constant adaptation of acquisition protocols. Those challenges, however, are in no way insurmountable for users with knowledge of general CT technique. The intent of this communication is to provide for those interested in and involved with coronary CT angiography a step-by-step manual, introducing our approach to performing coronary CT angiography. Included are considerations regarding appropriate patient selection, patient medication, radiation protection, contrast enhancement, acquisition and reconstruction parameters, image display and analysis techniques and also the radiology report. Our recommendations are based on our experience which spans the evolution of multidetector-row CT for cardiac applications from its beginnings to the most current iterations of advanced acquisition modalities, which we believe herald the entrance of this test into routine clinical practice.