Variation in tube voltage for pediatric neck 64VCT: Effect on radiation dose and image quality

Exposure to ionizing radiation can cause cancer, especially in children. In computed tomography (CT), a trade-off exists between the radiation dose and image quality. Few studies have investigated the effect of dose reduction on image quality in pediatric neck CT. We aimed to assess the effect of peak kilovoltage on the radiation dose and image quality in pediatric neck multidetector-row CT. Measurements were made using three phantoms representative of children aged 1, 5, and 10 years, with tube voltages of 80, 100, and 120 kilovoltage peak (kVp); tube current of 10, 40, 80, 120, 150, 200, and 250 mA; and exposure time = 0.5 s (pitch, 0.984:1). Radiation dose estimates were derived from the dose-length product with a 64-multidetector-row CT scanner. Images obtained from the control protocol (120 kVp) were compared with the 80- and 100-kVp protocols. The effective dose (ED) was determined for each protocol and compared with the 120-kVp protocol. Quantitative analysis entailed noise measurements by recording the standard deviation of attenuation for a circular 1-cm2 region of interest placed on homogeneous soft tissue structures in the phantom. The mean noise of the various kVp protocols was compared using the unpaired Student t-test. Reduction of ED was 37.58% and 68.58% for neck CT with 100 kVp and 80 kVp, respectively. The image noise level increased with the decrease in peak kilovoltage. Noise values were higher at 80 kVp at all neck levels, but did not increase at 100 kVp, compared to 120 kVp in the three phantoms. The measured noise difference was the greatest at 80 kVp (absolute increases<2.5 HU). The subjective image quality did not differ among the protocols. Thus, reducing voltage from 120 to 80 kVp for neck CT may achieve ED reduction of 68.58%, without compromising image quality.

Efficiency Assessment of Multidetector-Row Computed Tomographic Angiography Using Reconstruction With Locoregional Perforator Flaps

Background: Reconstruction with the use of perforator flaps makes it possible to make the skin surface resistant to the influence of mechanical factors and as similar to the lost skin cover as possible. However, while planning any flap, along with the design of the required shape and size, its blood supply should be taken into account to ensure optimal viability. Therefore, the task to precisely determine the topographic–anatomical relationships suitable for the formation of a pedicle of perforators is still relevant. The aim of this study was to increase the efficiency of surgical reconstruction of wound defects by transposition of locoregional perforator flaps. Methods: The authors conducted a retrospective analysis of 72 cases of reconstruction by means of locoregional perforator flaps with vascular pedicle detachment to determine the efficiency of preoperative diagnostic preparation with the help of multidetector-row computed tomographic angiography (MDCT) in the process of reconstruction. Thirty-seven individual cases of surgical interventions were chosen using a case-controlled study from the study group when MDCT with angiography was used for preoperative planning of perforator flaps, as well as 35 control cases similar in terms of important predictive peculiarities with the reconstruction at the same level of difficulty. The patient groups were precisely matched by gender ( P = .950), age ( P = .804), flap area ( P = .192), and type of reconstruction that was performed. Results: In all cases, the location of the perforator with a diameter greater than 1.0 mm was marked. All perforators determined during MDCT scanning were faultlessly localized intraoperatively. The distance between the intraoperative position of the perforator and the position obtained in the result of the examination did not exceed 1 cm. There was no need to change the planned design of the flap intraoperatively. In all cases where MDCT was performed, the duration of the surgical procedure varied from 60 to 150 minutes (average: 120.77 [18.90] minutes) and was reduced by 49.40 minutes (95% CI: 39.17-59.63) compared with the patients who did not undergo preoperative visualization of perforators where the average duration of the operation was 170.17 (19.19) minutes (from 140 to 220 minutes). Among the patients examined by MDCT, surgical complications were noted in 5 cases (13.51%) compared to 14 cases (40.00%) in the control group. Conclusions: The preoperative MDCT for the locoregional perforator flap reconstruction makes it possible to increase the efficiency of patient treatment given the reduction in surgery duration by 49.40 minutes (95% CI: 39.17-59.63) on average and the reduction in the level of postsurgery complications from 40% to 13.5% compared with the group of patients in whom presurgical visualization was not performed ( P = .031).

Preoperative Determination of the Size of the Semitendinosus and Gracilis Tendon by Multidetector Row CT Scanner for Anterior Cruciate Ligament Reconstruction

Accurately measuring the length and diameter of the hamstring tendon autograft preoperatively is important for planning anterior cruciate ligament (ACL) reconstructive surgery. The purpose of this study was to assess the reliability of three-dimensional computed tomography (3D CT) scanning technique to produce the actual measurement of the gracilis and semitendinosus (GT and ST, respectively) tendon grafts' length and diameter for surgery. Ninety patients were scheduled for ACL reconstruction with hamstring autograft. Before the surgery, patients were examined under the multidetector row CT scanner and the ST and GT tendons were qualitatively measured by a volume-rendering technique. The length of ST and GT was measured with 3D CT compared with the length of the harvested ST and GT. The cross-sectional area (CSA) of ST and GT measured with 3D CT compared with the ST and GT graft diameter. Tendon size measured preoperatively and during surgery were statistically compared and correlated. The GT tendons length and cross-sectional area measured during surgery was both shorter and smaller compared with the ST tendon. GT and ST tendon length were correlated to patients' body index such as the height and weight (p < 0.05). However, the correlation levels were low to medium (r = 0.23–0.49). There was strong correlation between the lengths of GT (r = 0.76; p < 0.001) and ST (r = 0.87; p < 0.001) measured with the 3D CT and tendon length at surgery. There was a moderate correlation between graft diameter measured at surgery and 3D CT cross-sectional area (r = 0.31; p < 0.05). A multidetector row CT scanner can determine the ST and GT tendons' length and diameter. These measurements can be used for preoperative planning to help determine the surgical method and counsel patients on appropriate graft choices prior to surgery.