Feasibility and reliability of high-resolution phase-contrast quantitative-flow magnetic resonance imaging for assessing femoral head blood flow: a prospective study.

Background: The early identification of abnormal blood supply to the femoral head is crucial for timely intervention. High-resolution phase-contrast quantitative-flow (Q-flow) magnetic resonance imaging (MRI) is a promising non-invasive technique for quantitatively assessing blood flow to the femoral head. This study aimed to evaluate the feasibility and reliability of Q-flow in quantifying blood flow to the femoral head.

Methods: This prospective study included 10 healthy volunteers (mean age =35±8.38 years, 6 women), 10 women with systemic lupus erythematosus (SLE), who were using corticosteroids (mean age =36.1±5.47 years), and 10 age-matched healthy women for the SLE patients, who served as controls (mean age =36.2±4.83 years). Q-flow scans were performed on all the participants from October 2023 to August 2024. Q-flow reliability, including retest reliability between scans, and intra- and inter-rater reliability, was evaluated using data from the healthy volunteers. Further, the efficacy of Q-flow was evaluated by comparing the quantification data between the SLE and control groups.

Results: Q-flow showed good-to-excellent reliability for the arterial flow parameters [intra-class correlation coefficient (ICC): 0.61-1], except for the regurgitant fraction (RF; ICC: 0.01-0.97). Q-flow also showed good-to-excellent reliability for the vein flow parameters (ICC: 0.63-1), except for the retest reliability of the RF (ICC: 0.04-0.9), mean velocity (MV; ICC: 0.46-0.84), and peak systolic velocity (PSV; ICC: 0.5-0.73). Compared with the controls, the SLE patients had significantly reduced arterial flow in the medial femoral circumflex artery (MFCA) [stroke and stroke distance (SD), P=0.01 and P<0.01], lateral femoral circumflex artery (LFCA) [stroke, mean flux (MF), SD, MV, and PSV, all P<0.01], and deep MFCA (stroke, MF, SD, MV, and PSV, all P<0.01).

Conclusions: The high-resolution phase-contrast Q-flow technique exhibited acceptable reliability and the capacity to detect early changes in arterial blood flow to the femoral head, highlighting its potential clinical applicability.