Effect of increasing the sampling interval to 2 seconds on the radiation dose and accuracy of CT perfusion of the head and neck.

PURPOSE: To evaluate the effect of increasing the sampling interval from 1 second (1 image per second) to 2 seconds (1 image every 2 seconds) on computed tomographic (CT) perfusion (CTP) of head and neck tumors. MATERIALS AND METHODS: Twenty patients underwent CTP studies of head and neck tumors with images acquired in cine mode for 50 seconds using sampling interval of 1 second. Using deconvolution-based software, analysis of CTP was done with sampling interval of 1 second and then 2 seconds. Perfusion maps representing blood flow, blood volume, mean transit time, and permeability surface area product (PS) were obtained. Quantitative tumor CTP values were compared between the 2 sampling intervals. Two blinded radiologists compared the subjective quality of CTP maps using a 3-point scale between the 2 sampling intervals. Radiation dose parameters were recorded for the 2 sampling interval rates. RESULTS: No significant differences were observed between the means of the 4 perfusion parameters generated using both sampling intervals; all P >0.05. The 95% limits of agreement between the 2 sampling intervals were -65.9 to 48.1) mL/min per 100 g for blood flow, -3.6 to 3.1 mL/100 g for blood volume, -2.9 to 3.8 seconds for mean transit time, and -10.0 to 12.5 mL/min per 100 g for PS. There was no significant difference between the subjective quality scores of CTP maps obtained using the 2 sampling intervals; all P > 0.05. Radiation dose was halved when sampling interval increased from 1 to 2 seconds. CONCLUSIONS: Increasing the sampling interval rate to 1 image every 2 seconds does not compromise the image quality and has no significant effect on quantitative perfusion parameters of head and neck tumors. The radiation dose is halved.

Serum vitamin D level and bone mineral density in premenopausal Egyptian women with fibromyalgia.

Patients with fibromyalgia syndrome (FMS) have impaired mobility and therefore get less sunlight exposure, we postulated that they may be at increased risk of developing osteoporosis (OP). The aim of this study was to assess and compare serum vitamin D level and bone mineral density (BMD) value in patients with primary FMS (PFMS) and healthy controls. A total of 50 patients with PFMS participated in this case-control study, and 50 healthy females who were age-matched to the patients were used as the control group. Venous blood samples collected from all subjects were used to evaluate serum 25-hydroxyvitamin D3 (25-OHD). BMD was measured at the lumbar spine (L2-L4) anteroposterior, femoral neck and forearm by dual-energy X-ray absorptiometry. Patients with PFMS had significantly lower serum 25-OHD than controls (15.1 ± 6.1 and 18.8 ± 5.4 ng/ml, respectively, p = 0.0018). Apart from the BMD in the lumbar spine, which was significantly lower in the PFMS patients compared with controls (p = 0.0012), no significant difference was found in other measures of BMD. Compared to PFMS patients who had serum level of the 25-OHD >20 ng/ml, the patients with 25-OHD ≤20 ng/ml are more likely to have impaired short memory (46.4 vs. 13.6%, respectively, p = 0.0136), confusion (50 vs. 18.2%, respectively, p = 0.0199), mood disturbance (60.7 vs. 27.3%, respectively, p = 0.0185), sleep disturbance (53.6 vs. 22.7%, respectively, p = 0.0271), restless leg syndrome (57.1 vs. 27.3%, respectively, p = 0.0346) and palpitation (67.9 vs. 36.4%, respectively, p = 0.0265). Serum level of the 25-OHD is inversely correlated with visual analogue scale (VAS) of pain (p = 0.016), Beck score for depression (p = 0.020) and BMD at lumbar spine (p = 0.012). The lumbar BMD inversely correlated with VAS of pain (p = 0.013) and Beck score for depression (p = 0.016). This study confirmed high prevalence of hypovitaminosis D among in patients with PFMS. This study confirmed the concept that FMS is a risk factor for OP. Based on this, an early nutrition program rich in calcium and vitamin D, appropriate exercise protocols, and medical treatment should be considered in these patients in terms of preventing OP development.