Evaluation of Radiation Dose and Image Quality using High-Pitch 70-kV Chest CT in Immunosuppressed Patients. / Evaluation der Strahlendosis und Bildqualität von High-Pitch-70-kV-CT-Untersuchungen des Thorax bei immunsupprimierten Patienten.

PURPOSE: The aim of the study was to evaluate high-pitch 70-kV CT examinations of the thorax in immunosuppressed patients regarding radiation dose and image quality in comparison with 120-kV acquisition. MATERIALS AND METHODS: The image data from 40 patients (14 women and 26 men; mean age: 40.9 ±â€Š15.4 years) who received high-pitch 70-kV CT chest examinations were retrospectively included in this study. A control group (n = 40), matched by age, gender, BMI, and clinical inclusion criteria, had undergone standard 120-kV chest CT imaging. All CT scans were performed on a third-generation dual-source CT unit. For an evaluation of the radiation dose, the CT dose index (CTDIvol), dose-length product (DLP), effective dose (ED), and size-specific dose estimates (SSDE) were analyzed in each group. The objective image quality was evaluated using signal-to-noise (SNR) and contrast-to-noise ratios (CNR). Three blinded and independent radiologists evaluated subjective image quality and diagnostic confidence using 5-point Likert scales. RESULTS: The mean dose parameters were significantly lower for high-pitch 70-kV CT examinations (CTDIvol, 2.9 ±â€Š0.9 mGy; DLP, 99.9 ±â€Š31.0 mGyxcm; ED, 1.5 ±â€Š0.6 mSv; SSDE, 3.8 ±â€Š1.2 mGy) compared to standard 120-kV CT imaging (CTDIvol, 8.8 ±â€Š3.7mGy; DLP, 296.6 ±â€Š119.3 mGyxcm; ED, 4.4 ±â€Š2.1 mSv; SSDE, 11.6 ±â€Š4.4 mGy) (P≤ 0.001). The objective image parameters (SNR: 7.8 ±â€Š2.1 vs. 8.4 ±â€Š1.8; CNR: 7.7 ±â€Š2.4 vs. 8.3 ±â€Š2.8) (P≥ 0.065) and the cumulative subjective image quality (4.5 ±â€Š0.4 vs. 4.7 ±â€Š0.3) (p = 0.052) showed no significant differences between the two protocols. CONCLUSION: High-pitch 70-kV thoracic CT examinations in immunosuppressed patients resulted in a significantly reduced radiation exposure compared to standard 120-kV CT acquisition without a decrease in image quality. KEY POINTS: · Third-generation dual-source CT units enable high-pitch 70-kV CT examinations of the chest.. · High-pitch 70-kV CT examinations show a significantly reduced radiation dose compared to standard 120-kV CT examinations.. · High-pitch 70-kV CT examinations of the chest show comparable objective and subjective image quality.. · Subjectively deteriorated image noise and sharpness of 70-kV CT did not impact diagnostic confidence.. CITATION FORMAT: · Yel I, Martin SS, Wichmann JL et al. Evaluation of Radiation Dose and Image Quality using High-Pitch 70-kV Chest CT in Immunosuppressed Patients . Fortschr Röntgenstr 2019; 191: 122 - 129.

Characterization of Severe Arterial Phase Respiratory Motion Artifact on Gadoxetate Disodium-Enhanced MRI - Assessment of Interrater Agreement and Reliability.

PURPOSE: To assess the interrater agreement and reliability of experienced abdominal radiologists in the characterization and grading of arterial phase gadoxetate disodium-related respiratory motion artifact on liver MRI. MATERIALS AND METHODS: This prospective multicenter study was initiated by the working group for abdominal imaging within the German Roentgen Society (DRG), and approved by the local IRB of each participating center. 11 board-certified radiologists independently reviewed 40 gadoxetate disodium-enhanced liver MRI datasets. Motion artifacts in the arterial phase were assessed on a 5-point scale. Interrater agreement and reliability were calculated using the intraclass correlation coefficient (ICC) and Kendall coefficient of concordance (W), with p < 0.05 deemed significant. RESULTS: The ICC for interrater agreement and reliability were 0.983 (CI 0.973 - 0.990) and 0.985 (CI 0.978 - 0.991), respectively (both p < 0.0001), indicating excellent agreement and reliability. Kendall's W for interrater agreement was 0.865. A severe motion artifact, defined as a mean motion score ≥ 4 in the arterial phase was observed in 12 patients. In these specific cases, a motion score ≥ 4 was assigned by all readers in 75 % (n = 9/12 cases). CONCLUSION: Differentiation and grading of arterial phase respiratory motion artifact is possible with a high level of inter-/intrarater agreement and interrater reliability, which is crucial for assessing the incidence of this phenomenon in larger multicenter studies. KEY POINTS: · Inter- and intrarater agreement for motion artifact scoring is excellent among experienced readers.. · Interrater reliability for motion artifact scoring is excellent among experienced readers.. · Characterization of severe motion artifacts proved feasible in this multicenter study.. CITATION FORMAT: · Ringe KI, Luetkens JA, Fimmers R et al. Characterization of Severe Arterial Phase Respiratory Motion Artifact on Gadoxetate Disodium-Enhanced MRI - Assessment of Interrater Agreement and Reliability. Fortschr Röntgenstr 2017; 190: 341 - 347.

Microwave Ablation (MWA): Basics, Technique and Results in Primary and Metastatic Liver Neoplasms - Review Article.

Purpose The locoregional interventional oncological treatment approach is an accepted modality for liver neoplasms, especially for hepatocellular carcinoma (HCC) and oligonodular liver metastases. Materials and Methods The main aim of ablation therapies like microwave ablation (MWA) is to eradicate all malignant cells in a minimally invasive technique under imaging guidance while preserving the healthy tissue with a sufficient safety margin (at least 5 mm) surrounding the ablated lesion. Results Ablation therapy can be performed via a percutaneous, laparoscopic or intraoperative approach under ultrasound, MRI or CT guidance for adequate localization and monitoring of the ablation process. Conclusion Ablation is the method of choice for oligonodular HCCs ≤ 3 cm. The technical success rate varies from 88 % to 98 % and progression-free survival (PFS) at 3 years from 27 % to 91.7 %. The same criteria apply to the therapy of liver metastases. Key Points · Careful selection of patients proves to be essential for optimum results of MWA. · Interventionists should be familiar with all aspects of complication and rapid assessment of imaging methods in order to evaluate induced damage by thermal ablation. · MWA seems to have some advantages over radiofrequency ablation, like shorter ablation time, less pain, less heat sink effect; however, scientific proof is needed. Citation Format · Vogl TJ, Nour-Eldin A, Hammerstingl RM et al. Microwave Ablation (MWA): Basics, Technique and Results in Primary and Metastatic Liver Neoplasms - Review Article. Fortschr Röntgenstr 2017; 189: 1055 - 1066.