The Value of Intracranial Hemodynamic Parameters Derived From Phase‐Contrast MRI in Predicting Severe Acute Mountain Sickness

ABSTRACT Background Severe acute mountain sickness (sAMS) impacts the quality of life in individuals rapidly ascending to high altitudes. Intracranial hemodynamics are pathophysiologically linked to sAMS and may assist in identifying individuals susceptible to sAMS. Purpose To explore the predictive value of intracranial hemodynamic parameters for sAMS prior to rapid high‐altitude exposure in normal subjects. Study Type Prospective. Subjects Seventy‐two healthy volunteers (median age, 26.5 years; 45 males). Thirteen developed sAMS (Lake Louise Score ≥ 10) after rapid ascent to 4411 m. Field Strength/Sequence 3‐T, phase‐contrast MRI (PC‐MRI). Assessment On the plains, four PC‐MRI scans were performed in each subject, with one PC‐MRI scan for each of the following states: normal breathing (NB), light Valsalva maneuver (VM), moderate VM, and heavy VM. Manual segmentation along the luminal boundary of the right internal carotid artery (ICA) and internal jugular vein (IJV) was performed to obtain the following hemodynamic parameters for each state: vascular sectional area (S), relative systolic peak waveform time (RT), arteriovenous delay time (AVD), mean blood flow (MBF), mean blood velocity (MBV), pulsatility index (PI), and resistance index (RI). Statistical Tests Independent t ‐tests, Mann–Whitney U tests, chi‐squared tests, one‐way repeated measures ANOVA, Friedman tests, univariable and multivariable logistic regression analysis. The predictive performance for identifying individuals susceptible to sAMS was evaluated using the area under the receiver operating characteristic curve (AUC) and the DeLong test. A p value < 0.05 was considered statistically significant. Results The independent predictive factors for sAMS were as follows: AVD under NB (odds ratio [OR] = 0.922), S IJV under light VM (OR = 1.031), RI ICA under light VM (OR = 0.858), S IJV under moderate VM (OR = 1.038), and S IJV under heavy VM (OR = 1.042). The predictive model using multistate parameters demonstrated a better AUC (0.876) compared with single‐state models. Data Conclusion PC‐MRI based intracranial hemodynamic parameters may have predictive value for identifying individuals susceptible to sAMS. Evidence Level 2. Technical Efficacy Stage 2.