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Kidney morphology in pregnancy using T2-weighted MRI

Research output: Contribution to journalArticlepeer-review

Original languageEnglish
Pages (from-to)548-552
Number of pages5
JournalClinical Radiology
Issue number7
Accepted/In press2022
PublishedJul 2022

Bibliographical note

Funding Information: The authors thank Jim Carmichael for advising on the study concept and training in the measurement of kidney morphology and Jacqueline Matthews for her help in data extraction. The iFind study is funded by the Wellcome Trust (IEH Award 102431). L.C.C. is funded by the National Institute for Health Research (NIHR) (Research Professorship RP-2014-05-019 ). K.W. and F.C.R. are funded by the NIHR Biomedical Research Centre based at Guy's and St Thomas' NHS Foundation Trust and King's College London and the NIHR Clinical Research Facility . The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. Publisher Copyright: © 2022 The Royal College of Radiologists

King's Authors


AIM: To report the morphology of maternal kidneys captured on fetal magnetic resonance imaging (MRI) including kidney length, volume, renal pelvis diameter, and corticomedullary differentiation in pregnancy. MATERIALS AND METHODS: A retrospective study of maternal kidney morphology captured incidentally on fetal MRI. Women without chronic kidney disease, with a complete view of both kidneys and a singleton pregnancy were included. Kidney length, maximal renal pelvis diameter, kidney volume, and corticomedullary differentiation ratio were measured independently in duplicate. Associations with maternal and pregnancy variables were explored using linear regression. RESULTS: MRI images from 42 women were performed at 22–32 weeks' gestation. Serum creatinine concentrations are not checked routinely during pregnancy and were available for 15 (36%) women, with a median creatinine of 57 μmol/l (IQR: 50–63 μmol/l). Mean interpolar lengths were 10.9 and 10.4 cm for the left and right kidneys and varied with height. Mean maximal renal pelvis diameters were 9 mm and 12 mm, with upper reference intervals of 17 and 25 mm for the left and right kidneys, respectively. Renal volume in pregnancy was within the non-pregnant reference interval and varied with height and gestation. CONCLUSIONS: Maternal kidney length and volume in pregnancy are within the normal reference intervals for non-pregnant women. Renal pelvis diameter in pregnancy measured using MRI is substantially higher than described previously by ultrasound, with implications for routine reporting.

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