Intravoxel incoherent motion MRI for early detection and assessment of renal injury after cardiac arrest and resuscitation in a rat model.

Abstract

OBJECTIVE: To investigate the utility of intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) for early detection of renal injury 24&#x2009;h after cardiac arrest and cardiopulmonary resuscitation. MATERIALS AND METHODS: Twenty-four male Sprague-Dawley rats were randomized into cardiac arrest (n&#x2009;=&#x2009;15) and sham-operated (n&#x2009;=&#x2009;9) groups. Five cardiac arrest rats died during the procedure, resulting in 10 cardiac arrest and 9 sham rats for analysis. IVIM-MRI and renal parameters were assessed 24&#x2009;h after cardiac arrest and cardiopulmonary resuscitation. Diffusion-related parameters, including apparent diffusion coefficient (ADC), true diffusion coefficient (D), pseudo-diffusion coefficient (D*), perfusion fraction (f), and exponential ADC (eADC), were obtained. The primary imaging endpoint was defined as D. Following completion of MRI, renal function, histopathology, and expression of apoptosis markers (Bcl-2, Caspase-3), water channel protein aquaporin-3, and tight junction proteins (zonula occludens-1, occludin) were subsequently evaluated. RESULTS: Despite preserved conventional renal function, IVIM MRI detected early renal alterations 24&#x2009;h after cardiac arrest. Compared with the sham group, eADC, D, ADC, D*, and f values were all significantly reduced. Histopathological analysis revealed pronounced tubular epithelial injury, increased apoptosis (Bcl-2, p&#x2009;<&#x2009;0.001; Caspase-3, p&#x2009;=&#x2009;0.010), and reduced expression of aquaporin-3 (p&#x2009;=&#x2009;0.039), zonula occludens-1 (p&#x2009;<&#x2009;0.001), and occludin (p&#x2009;<&#x2009;0.001). CONCLUSION: IVIM MRI enables early, noninvasive detection of renal injury 24&#x2009;h after cardiac arrest and CPR, reflecting tubular injury, tight junction disruption, and perfusion deficits, potentially facilitating timely intervention and improving prognosis. RELEVANCE STATEMENT: This approach may facilitate individualized therapy and improve post-cardiac arrest syndrome outcome. KEY POINTS: The long-term outcomes of cardiac arrest remain poor due to post-cardiac arrest syndrome. IVIM MRI enables early, noninvasive detection of renal injury after cardiac arrest and cardiopulmonary resuscitation. This approach may facilitate individualized therapy and improve post-cardiac arrest syndrome.