This ask force delivered a systematic review and statement paper evaluating and summarizing data on renal T1- and T2-mapping in humans, and providing recommendations for upcoming research efforts in order to promote T1/T2-mapping into clinical practice.
Deliverable: review paper
Wolf M, de Boer A, Sharma K, Boor P, Leiner T, Sunder-Plasmann G, Moser E, Caroli A, Jerome NP
Magnetic resonance imaging T1- and T2-mapping to assess renal structure and function: a systematic review and statement paper
Nephrology Dialysis Transplantation, Volume 33, Issue suppl_2, 1 September 2018, Pages ii41–ii50, https://doi.org/10.1093/ndt/gfy198
Abstract. This systematic review, initiated by the COST Action PARENCHIMA, focuses on potential clinical applications of magnetic resonance imaging in renal non-tumour disease magnetic resonance relaxometry (MRR), specifically, the measurement of the independent quantitative magnetic resonance relaxation times T1 and T2 at 1.5 and 3 Tesla, respectively. Healthy subjects show a distinguishable corticomedullary-differentiation (CMD) in T1, and a slight CMD inT2. Increased cortical T1-values, that is reduced T1-CMD, were reported in acute allograft rejection (AAR), and diminished T1-CMD in chronic allograft rejection. However, ambiguous findings were reported, and AAR could not be sufficiently differentiated from acute tubular necrosis and cyclosporine nephrotoxicity. Despite this, one recent quantitative study showed in renal transplants a direct correlation between fibrosis and T1-CMD. Additionally, various renal diseases, including renal transplants, showed a moderate to strong correlation between T1-CMD and renal function. Recent T2 studies observed increased values in renal transplants compared to healthy subjects, and in early-stage autosomal dominant polycystic kidney disease (ADPKD), which could improve diagnosis and progression assessment compared to total kidney volume alone in early-stage ADPKD. Renal MRR is suggested to be sensitive to renal perfusion, ischaemia/oxygenation, oedema, fibrosis, hydration and comorbidities, which reduce specificity. Due to the lack of standardization in patient preparation, and acquisition protocols and adequate patient selection, no widely accepted reference values are currently available. Therefore, this review encourages efforts to optimize and standardize (multiparametric) protocols to increase specificity and to tap the full potential of renal MRR in future research.