Portable Ultra-Low-field MRI in Africa: an Access Technology in Search of an Evidence Base Built Without a Safety Net

PURPOSE:Portable ultra-low-field (ULF) magnetic resonance imaging (MRI) is usually judged by how closely it approaches high-field performance. This opinion paper argues that, in many resource-constrained settings, the question is miscast, and sets out how the technology should instead be evaluated. METHOD:Drawing on recent systematic reviews and meta-analyses of portable ULF-MRI and on more than fifteen years of neuroradiology practice in Nigeria, the paper examines whether pooled diagnostic-accuracy estimates transfer to settings where the portable scanner may be the only imaging device available. RESULTS:Diagnostic accuracy and clinical utility are not the same thing. Pooled estimates were derived almost entirely where conventional MRI or computed tomography was immediately available; transferring them assumes comparable case-mix and workflow (spectrum and implementation effects) and, critically, overlooks that without a fallback, the consequences of false-negative, indeterminate and non-diagnostic examinations are far graver. A pooled acute-ischaemic-stroke sensitivity near 73% is a manageable adjunct with backup but means roughly one in four infarcts is missed and left uncorrected without it. Four arguments follow: accuracy estimates may be optimistic and are insufficient for unsupported pathways; interpretation capacity and medicolegal responsibility are decisive but underestimated constraints, alongside cost, power and connectivity; quantitative normative morphometry rests on non-African reference data; and low-field practice in Africa is a decades-old continuity. CONCLUSIONS:Portable ULF-MRI should be evaluated as an access technology on the terms its setting imposes, using a minimum outcome set - including non-diagnostic and indeterminate rates, downstream consequences, and cost per completed diagnostic pathway - not sensitivity alone.