Short-Term Measurement Repeatability of a Simplified Intravoxel Incoherent Motion (IVIM) Analysis for Routine Clinical Diffusion-Weighted Imaging in Malignant Liver Lesions and Liver Parenchyma at 1.5 T.

OBJECTIVES: To evaluate measurement repeatability of parameters derived from simplified intravoxel incoherent motion (IVIM) analysis of diffusion-weighted imaging (DWI) using 3 b-values. MATERIALS AND METHODS: 24 patients (16 male, 8 female, mean age: 67 years) with hepatic malignancy (HCC: 10, metastases: 14) underwent 29 liver MRI examinations at 1.5 T. Respiratory-triggered DWI (b = 0, 50, 800 s/mm2) was acquired twice. Parameter maps of the apparent diffusion coefficient ADC(0,800), estimated diffusion coefficient D' and perfusion fraction f' were calculated. Measurement repeatability for a region of interest (ROI) placed in one lesion and liver parenchyma per lobe was assessed by intra-session variation coefficients (CV). RESULTS: 86 ROIs (43 lesions, 43 parenchymas) were analyzed. Parameters did not significantly differ between measurements. Repeatability was excellent for ADC(0,800) and D' and good for f' in parenchyma (CVs: 7.3 %, 9.8 %, 13.0 %) and lesions (CVs: 7.5 %, 8.5 %, 11.0 %). Differences in CV-values between liver and lesions were not significant. Repeatability was better for the right than for the left lobe by tendency, for parenchyma (CVs: 6.4 % vs 8.4 %, 8.8 % vs 10.9 %, 10.5 % vs 16.0 %) and for lesions (CVs: 6.9 % vs 8.1 %, 7.5 % vs 9.5 %, 9.5 % vs 12.7 %). CONCLUSION: Measurement repeatability is excellent for ADC(0,800) and D' values and good for f' values using the simplified IVIM approach, both in lesions and liver parenchyma. Repeatability was better for lesions in the right compared to the left liver lobe. KEY POINTS: · Repeatability obtained by a simplified IVIM analysis approach is good to excellent.. · Repeatability is better for the right than for the left liver lobe.. · The simplified approach may be helpful in diagnosing and monitoring liver malignancies.. CITATION FORMAT: · Pieper CC, Sprinkart AM, Kukuk GM et al. Short-Term Measurement Repeatability of a Simplified Intravoxel Incoherent Motion (IVIM) Analysis for Routine Clinical Diffusion-Weighted Imaging in Malignant Liver Lesions and Liver Parenchyma at 1.5T. Fortschr Röntgenstr 2019; 191: 199 - 208.

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.