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bioRxiv2025

Towards whole-heart quantitative myocardial perfusion using a dual-sequence framework with multiband acceleration

Background2D Quantitative Myocardial Perfusion (Qperf) MRI is limited by its inability to provide complete myocardial coverage within a heartbeat interval. This study developed and evaluated dual saturation multiband-accelerated Qperf imaging to achieve near-complete left ventricular coverage in free-breathing at an adequate in-plane spatial resolution, using a semi-automated Myocardial Blood Flow (MBF) framework for quantification deployable directly on the scanner console. MethodsA dual-saturation single-band QPerf sequence was modified for multiband imaging, enabling the acquisition of 6 high-resolution myocardial slices plus Arterial Input Function (AIF) during free-breathing. The technique was evaluated in 16 sedated pigs (13 healthy and 3 with LAD occlusion) under rest conditions on a 3T MRI scanner. Additionally, two healthy pigs underwent stress imaging as well. Statistical comparisons were performed between multiband and single-band MBF values in corresponding AHA segments. ResultsQualitatively, multiband QPerf provided superior left ventricular coverage and comparable image quality to single-band Qperf MBF maps, potentially enabling a more comprehensive detection of perfusion defects at rest. Quantitatively, multiband QPerf yielded lower MBF values than single-band QPerf (p < 0.01). However, Bland-Altman analysis (mean difference: -0.17 ml/min/g; 95% CI: -1.12 to 0.79 ml/min/g) and Passing-Bablok regression (intercept: -0.01 ml/min/g; 95% CI: - 0.37 to 0.28 ml/min/g) indicated that such discrepancy remained within the expected confidence intervals. Furthermore, the Passing-Bablok slope (0.88; 95% CI: 0.73-1.06) confirmed that mb-QPerf maintained sensitivity comparable to sb-QPerf in detecting perfusion changes under rest conditions. Finally, there was an overall increase in MBF values during stress vs rest conditions (average MBF Ratio 1.67 {+/-} 0.31) when comparing healthy pigs. ConclusionMultiband-accelerated Qperf is feasible, providing improved left ventricular coverage, adequate in-plane resolution, and a semi-automated MBF quantification framework directly on the scanner console. Compared to its single-band counterpart, multiband QPerf demonstrated a more comprehensive visualization of perfusion defects and comparable sensitivity and accuracy in detecting perfusion changes at rest. Further research and clinical validation in patient populations are needed to confirm its utility in the diagnosis of coronary artery disease.

bioengineering↗

bioRxiv2019

The thalamic basis of outcome and cognitive impairment in traumatic brain injury

ObjectiveTo understand how, biologically, the acute event of traumatic brain injury gives rise to a long-term disease, we address the relationship between evolving cortical and subcortical brain damage and measures of functional outcome and cognitive functioning at six months post-injury.\n\nMethodsLongitudinal analysis of clinical and MRI data collected, in a tertiary neurointensive care setting, in a continuous sample of 157 patients surviving moderate to severe traumatic brain injury between 2000 and 2018. For each patient we collected T1- and T2-weighted MRI data, acutely and at a six-months follow-up, as well as acute measures of injury severity (Glasgow Coma Scale) and follow-up measures of functional impairment (Glasgow Outcome Scale extended), and, in a subset of patients, neuropsychological measures of attention, executive functions, and episodic memory.\n\nResultsIn the final cohort of 113 subcortical and 92 cortical datasets that survived (blind) quality control, extensive atrophy was observed over the first six months post-injury across the brain. Nonetheless, only atrophy within subcortical regions, particularly in left thalamus, were associated with functional outcome and neuropsychological measures of attention, executive functions, and episodic memory. Furthermore, when brought together in an analytical model, longitudinal brain measurements could distinguish good versus bad outcome with 90% accuracy, whereas acute brain and clinical measurements alone could only achieve 20% accuracy.\n\nInterpretationDespite great injury heterogeneity, secondary thalamic pathology is a measurable minimum common denominator mechanism directly relating biology to clinical measures of outcome and cognitive functioning, potentially linking the acute \"event\" and the long(er)-term \"disease\" of TBI.

neuroscience↗