Estimated radiation dose and image quality comparison of the scan protocols in dual-source computed tomography coronary angiography.

INTRODUCTION: Radiation exposure from computed tomography coronary angiography (CTCA) is of particular concern and several techniques have been introduced to lower the radiation dose. In this study, we aimed to compare the diagnostic image quality and estimated radiation dose of the three CTCA acquisition protocols in a recently introduced second generation dual-source computed tomography. METHODS: Two hundred consecutive subjects underwent dual-source CTCA by using high-pitch spiral, sequential and retrospective spiral protocols. Effective radiation dose, expressed in millisieverts, was calculated as the product of the dose-length product times a conversion factor of 0.014. Image quality was evaluated on a per-segment basis, with a four-point scale. RESULTS: For the high-pitch spiral, sequential and retrospective spiral protocols, mean effective radiation doses were 1.41 ± 0.56, 5.50 ± 2.06 and 7.79 ± 2.25 mSv and mean per-subject image scores were 2.8 ± 0.7, 2.2 ± 0.8 and 2.5 ± 0.8, respectively. Radiation dose of the high-pitch mode was significantly lower (P < 0.001) than the sequential and retrospective spiral modes, and statistical analysis for image quality revealed a significant difference between the high-pitch spiral and the sequential modes (P < 0.05). CONCLUSION: Dual-source CTCA using high-pitch acquisition considerably lowers radiation exposure in subjects with a low and stable heart rate and maintains good image quality, especially when the subjects have a body mass index ≤25 and a tube voltage of 80 or 100 kV is used. However, when sequential and retrospective spiral modes are used in the same device, mean radiation doses can increase roughly three and five times more, respectively.

A new transodontoid fixation technique for delayed type II odontoid fracture: technical note.

BACKGROUND: A different transodontoid screw fixation technique was studied in delayed type II odontoid fractures. This study presents observations on a different transodontoid fixation technique to remove and decrease the amount of sclerotic layers to accelerate the fusion process after the operation. METHODS: Ten cases of chronic type II odontoid fractures were operated on via transodontoid screw fixation between 2000 and 2007 which were admitted 6 weeks or later after the trauma. Four of these 10 delayed patients were operated on using a new anterior transodontoid screw fixation technique, whereas the other 6 delayed patients were operated on using classical anterior transodontoid screw fixation. RESULTS: Four delayed cases with type II odontoid fracture operated on via this new technique had good results throughout the minimum 38 months' follow-up period. We did not observe nonunion, infection, and/or other complications such as vascular or brain-stem injury. CONCLUSION: Transodontoid screw fixation should be considered as a preferable treatment modality. This surgical intervention may be an alternative to conservative treatment even for cases with delayed type II odontoid fractures.

Anterior cervical microdiscectomy with or without fusion.

BACKGROUND: Anterior cervical microdiscectomy (ACD) is commonly applied in the surgical treatment of cervical disc herniation. However, following discectomy procedure to perform a fusion process is still controversial. Therefore, a controlled, multicentric, prospective, randomized study was designed. MATERIAL AND METHOD: Totally 20 patients were operated. Eleven patients were operated with applying simple anterior microdiscectomy technique. Nine patients were operated via ACD and fusion with a semirigid plate technique. Preoperative and postoperative [immediate; postoperative first day and postoperative 1 y (mean 13.95 mo)] computed tomography studies and plain x-rays were obtained. The cervical disc and bilateral neural foramen heights of the operated level and adjacent segments were calculated. Pain assessment was performed using visual analog pain scale. Mann-Whitney statistical analysis method was applied to compare the outcomes for both groups. RESULTS: Satisfactory result was achieved in both groups. The pain scores for major complaint (arm pain) were decreased significantly in all patients after surgery regardless of the type of technique applied. The improvement in neck pain scores was significant only in patients who were treated with fusion procedure. There were no significant changes in disc height and neural foramen height measurements for both groups in adjacent levels in immediate and 1-year postoperative periods. The patients who were operated with simple ACD technique showed no significant decrease at postoperative first day in disc height and neural foramen height. However, the 1-year postoperative radiologic studies showed a significant decrease in disc height and neural foramen dimensions compared with preoperative values. The patients who were treated with fusion process showed a significant increase in disc height and nonsignificant increase in neural foramen heights at immediate postoperative study. However, with time, all dimensions showed significant decrease compared with preoperative values. CONCLUSIONS: ACD technique offers satisfactory outcome regardless of whether fusion process is applied or not. Fusion with semirigid plate offers an advantage at operated level in immediate postoperative period in regard of disc height and neural foramen height. However, semirigid anterior plates by definition do not stop subsidence and the advantage that is offered by this technique is not persistent. On the other hand, to apply fusion process with semirigid plate system offers significantly less narrowing in disc height compared with simple ACD technique.