An invasive minilaparoscopic biopsy of both liver lobes in AIH (AIH, AIH-PBC, and AIH-PSC) was more accurate for grading/staging disease activity than percutaneous biopsy, reflecting intrahepatic heterogeneity. Noninvasive LiverMultiScan cT1 demonstrated this heterogeneity, and its extent independently predicted disease flares, supporting multi-lobe sampling and cT1 for comprehensive assessment.