Hepatic Fat Quantification With Novel Ultrasound Based Techniques: A Diagnostic Performance Study Using Magnetic Resonance Imaging Proton Density Fat Fraction as Reference Standard.

Purpose: To assess the diagnostic performances of novel Tissue attenuation imaging (TAI) and Tissue scatter distribution imaging (TSI) tools in quantification of liver fat content using magnetic resonance imaging proton density fat fraction (MRI PDFF) as reference standard. Methods: Eighty consecutive patients with known or suspected non-alcoholic fatty liver disease (NAFLD) who volunteered to participate in the study comprised the study cohort. All patients underwent MRI PDFF scan and quantitative ultrasound (QUS) imaging using TAI and TSI tools. The cutoff values of ≥5%, ≥16.3% and ≥21.7% on MRI PDFF were used for mild, moderate and severe steatosis, respectively. Area under the Receiver operating characteristic (AUROC) curves were used to assess the diagnostic performance of TAI and TSI in detecting different grades of hepatic steatosis. Results: The AUROCs of TAI and TSI tools in detecting hepatosteatosis (MRI PDFF ≥5%), were 0.95 [95% Confidence Interval (CI): 0.91-0.99] (P < 0.001) and 0.96 (95% CI: 0.93-0.99) (P < 0.001), respectively. In distinguishing between different grades of steatosis, the values of 0.75, 0.86 and 0.96 dB/cm/MHz have 88%, 88% and 100% sensitivity, respectively, for TAI tool; and the values of 92.44, 96.64 and 99.45 have 90%, 92% and 91.7% sensitivity, respectively, for TSI tool. Conclusion: TAI and TSI tools accurately quantify liver fat content and can be used for the assessment and grading of hepatosteatosis in patients with known or suspected NAFLD.

Assessment of 3D T2-weighted high-sampling-efficiency technique (SPACE) for detection of cerebellar tonsillar motion: new useful sign for Chiari I malformation.

OBJECTIVE: To describe tonsillar blackout sign (TBS) on three-dimensional (3D)-SPACE, evaluate its performance in identifying Chiari malformation (CM1) as diagnostic marker, and investigate its role in differentiation of symptomatic and asymptomatic CM1. METHODS: One-hundred fifty-six patients were divided into two groups based on caudal displacement of cerebellar tonsils: CM1 (Group I) and non-CM1 (Group II). Group I was subclassified as symptomatic and asymptomatic by a neurosurgeon. Two radiologists evaluated TBS and cerebrospinal fluid flow abnormality. RESULTS: All subjects presenting TBS had CM1. Difference in presence of TBS between Group I and Group II was highly significant (P<.001).Grading of TBS in symptomatic patients was significantly higher than that in asymptomatic patients (P<.001). CONCLUSION: TBS is highly suggestive of CM1 and potentially useful in differentiation of symptomatic and asymptomatic CM1.