Objective: To evaluate the feasibility and image quality of low-dose CT of the paranasal sinuses using iterative reconstruction with adaptive-iterative dose reduction in three dimensions (AIDR 3D) in comparison with conventional image protocols of older scanner generations. Methods: Sinus CT scans of 136 patients were assessed retrospectively. Patients underwent CT either with low-dose settings (Protocol A: 80 kV, 30 mA s; Protocol B: 120 kV, 15 mA s or C: 80 kV, 90 mA s) reconstructed using AIDR 3D (Protocols A and B) or filtered back projection (FBP) (Protocol C) or with standard dose (Protocol D: 120 kV, 80 mA s) and FBP. Image quality was assessed in consensus by two blinded readers scoring the diagnostic image quality (from 1 5 excellent to 5 5 non-diagnostic) and conspicuity of important anatomic landmarks (from 0 5 not visible to 2 5 completely visible; maximum score of 16 points) as well as osseous structures (maximum score of 12 points). Dose-length product, effective dose (ED), CT dose index and scan length were retrieved for each scan and compared. Results: Mean ED could be lowered by 82% when using Protocol A. The best image quality was found using Protocol B (mean score 5 2.1 ± 0.51). Conspicuity of relevant anatomic landmarks was best with Protocol A (mean score 5 11.97 ± 1.88). Protocol B provided the highest conspicuity of osseous structures (mean score 5 8.27 ± 1.58). Image noise was highest in images obtained using Protocol A. Conclusions: AIDR 3D allows a significant dose reduction while maintaining a good diagnostic image quality and conspicuity of relevant anatomic structures.
Objectives: The aim of this study was to investigate ultrasound time-harmonic elastography for quantifying aortic stiffness in vivo in the context of aging and arterial hypertension. Materials and Methods: Seventy-four participants (50 healthy participants and 24 participants with long-standing hypertension) were prospectively included between January 2018 and October 2018, and underwent ultrasound time-harmonic elastography of the upper abdominal aorta. Compound maps of shear-wave speed (SWS) as a surrogate of tissue stiffness were generated from multifrequency wave fields covering the full field-of-view of B-mode ultrasound. Blood pressure and pulse wave velocity were measured beforehand. Interobserver and intraobserver agreement was determined in 30 subjects. Reproducibility of time-harmonic elastography was assessed in subgroups with repeated measurements after 20 minutes and after 6 months. Linear regression analysis, with subsequent age adjustment of SWS obtained, receiver operating characteristic analysis, and intraclass correlation coefficients (ICCs) were used for statistical evaluation. Results: Linear regression analysis revealed a significant effect of age on SWS with an increase by 0.024 m/s per year (P < 0.001). Age-adjusted SWS was significantly greater in hypertensives (0.24 m/s; interquartile range [IQR], 0.17-0.40 m/s) than in healthy participants (0.07 m/s; IQR, −0.01 to 0.06 m/s; P < 0.001). A cutoff value of 0.15 m/s was found to differentiate best between groups (area under the receiver operating characteristic curve, 0.966; 95% confidence interval, 0.93-1.0; P < 0.001; 83% sensitivity and 98% specificity). Interobserver and intraobserver variability was excellent (ICC, 0.987 and 0.937, respectively). Reproducibility was excellent in the short term (ICC, 0.968; confidence interval, 0.878-0.992) and good in the long term (ICC, 0.844; confidence interval, 0.491-0.959). Conclusions: Ultrasound time-harmonic elastography of the upper abdominal aorta allows quantification of aortic wall stiffness in vivo and shows significantly higher values in patients with arterial hypertension.
Background Computed tomography (CT)-guided periradicular infiltration remains a frequent interventional procedure for treatment of low back pain. Purpose To present an interventional ultra-low-dose protocol for CT-guided periradicular infiltration therapy and assess its application at different body mass index (BMI) levels. Material and Methods Over a period of 14 months, 79 patients underwent 183 CT-guided interventions for single-site lumbar periradicular therapy using an ultra-low-dose protocol with a basic setup of 100 kV and 5 mAs. Procedures were performed via intermittent fluoroscopy. A retrospective review was performed to analyze the parameters tube current and tube voltage, dose-length product, and BMI. Results The interventional ultra-low-dose protocol allowed safe treatment of 91.1% of the patients without a need for adapting the protocol. In seven patients with a higher BMI (range, 31-38 kg/m; mean, 34 kg/m), the tube current had to be increased to retain sufficient image quality. Only patients with a BMI of 30 and higher showed a significant correlation between BMI and dose-length product ( P value = 0.02), resulting in a slightly increased dose ( P value = 0.002). Conclusion The protocol presented for the interventional part of CT-guided periradicular infiltration allows to safely treat patients with a median calculated effective dose of 0.045 mSv (converted from a dose-length-product of 2.26 mGy*cm). Patients with a BMI of 30 and higher required a higher calculated effective dose with just one patient slightly exceeding 0.1 mSv.
BACKGROUND AND PURPOSE: The Neck Imaging Reporting and Data System was introduced to assess the probability of recurrence in surveillance imaging after treatment of head and neck cancer. This study investigated inter-and intrareader agreement in interpreting contrast-enhanced CT after treatment of oral cavity and oropharyngeal squamous cell carcinoma. MATERIALS AND METHODS:This retrospective study analyzed CT datasets of 101 patients. Four radiologists provided the Neck Imaging Reporting and Data System reports for the primary site and neck (cervical lymph nodes). The Kendall's coefficient of concordance (W), Fleiss k (k F ), the Kendall's rank correlation coefficient (t B ), and weighted k statistics (k w ) were calculated to assess inter-and intrareader agreement.RESULTS: Overall, interreader agreement was strong or moderate for both the primary site (W ¼ 0.74, k F ¼ 0.48) and the neck (W ¼ 0.80, k F ¼ 0.50), depending on the statistics applied. Interreader agreement was higher in patients with proved recurrence at the primary site (W ¼ 0.96 versus 0.56, k F ¼ 0.65 versus 0.30) or in the neck (W ¼ 0.78 versus 0.56, k F ¼ 0.41 versus 0.29). Intrareader agreement was moderate to strong or almost perfect at the primary site (range t B ¼ 0.67-0.82, k w ¼ 0.85-0.96) and strong or almost perfect in the neck (range t B ¼ 0.76-0.86, k w ¼ 0.89-0.95).
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