Background
The high operational cost of MRI limits its utility for hepatocellular carcinoma (HCC) screening. Abbreviated‐protocol dynamic contrast‐enhanced MRI (aMRI) may help lower cost while maintaining the high accuracy of complete‐protocol diagnostic MRI (cMRI).
Purpose
To compare aMRI to cMRI for HCC detection in cirrhosis patients.
Study Type
Cross‐sectional study.
Study Population
Cirrhosis patients undergoing MRI for suspected HCC.
Field Strength/Sequence
1.5T and 3T; aMRI (coronal T2‐weighted, axial dynamic contrast‐enhanced T1‐weighted fat‐suppressed sequences); cMRI (aMRI sequences and unenhanced axial T2‐, T1‐, and diffusion‐weighted sequences).
Assessment
From each cMRI, an abbreviated exam was created by extracting only the aMRI sequences. Five radiologists independently reviewed aMRI and cMRI and assigned per‐patient screening results by the presence/absence of any actionable observation per Liver Imaging and Reporting Data System v2018 (LI‐RADS 4, 5, M, or TIV categories). Per‐patient HCC status was determined by the composite reference standard of histopathology, follow‐up imaging, consensus expert panel imaging review, and clinical follow‐up.
Statistical Tests
Interreader agreement between aMRI and cMRI was compared with that of cMRI and tested for interchangeability against a tolerance margin of 0.05. Per‐patient screening sensitivity, specificity, and accuracy were compared between aMRI and cMRI and tested for equivalence against a tolerance margin of 0.05.
Results
In 93 cirrhosis patients, five radiologists recorded on average 121 liver observations. Interreader screening agreement probability (and 95% confidence interval confidence interval [CI]) was 0.914 [0.900, 0.926] between aMRI and cMRI, and 0.927 [0.908, 0.942] for cMRI; their difference was within the 0.05 margin for interchangeability. In 86 patients in whom a final HCC status could be determined, the detection sensitivity and specificity of aMRI was 0.921 [0.864, 0.956] and 0.886 [0.844, 0.918], within the 5% equivalence margin to cMRI, 0.936 [0.881, 0.965] and 0.883 [0.840, 0.915], respectively.
Data Conclusion
Abbreviated‐protocol screening MRI is interchangeable with, and equivalent to, complete‐protocol diagnostic MRI for per‐patient HCC detection in cirrhosis.
Level of Evidence: 4
Technical Efficacy: Stage 6
J. Magn. Reson. Imaging 2020;51:415–425.