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Technical Note: Clinical translation of the Rapid‐Steady‐State‐ T 1 MRI method for direct cerebral blood volume quantification
Author(s) -
PerlesBarbacaru TeodoraAdriana,
Tropres Irene,
Sarraf Michel G.,
Chechin David,
Zaccaria Affif,
Grand Sylvie,
Le Bas JeanFrançois,
Berger François,
Lahrech Hana
Publication year - 2015
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.4932218
Subject(s) - medicine , white matter , magnetic resonance imaging , nuclear medicine , blood volume , extravasation , ultrasound , radiology , pathology , cardiology
Purpose: In preclinical studies, the Rapid‐Steady‐State‐ T 1 (RSS T 1 ) MRI method has advantages over conventional MRI methods for blood volume fraction (BVf) mapping, since after contrast agent administration, the BVf is directly quantifiable from the signal amplitude corresponding to the vascular equilibrium magnetization. This study focuses on its clinical implementation and feasibility. Methods: Following sequence implementation on clinical Philips Achieva scanners, the RSS T 1 ‐method is assessed at 1.5 and 3 T in the follow‐up examination of neurooncological patients receiving 0.1–0.2 mmol/kg Gd‐DOTA to determine the threshold dose needed for cerebral BVf quantification. Confounding effects on BVf quantification such as transendothelial water exchange, transverse relaxation, and contrast agent extravasation are evaluated. Results: For a dose ≥0.13 mmol/kg at 1.5 T and ≥0.16 mmol/kg at 3 T, the RSS T 1 ‐signal time course in macrovessels and brain tissue with Gd‐DOTA impermeable vasculature reaches a steady state at maximum amplitude for about 8 s. In macrovessels, a BVf of 100% was obtained validating cerebral microvascular BVf quantification (3.5%–4.5% in gray matter and 1.5%–2.0% in white matter). In tumor tissue, a continuously increasing signal is detected, necessitating signal modeling for tumor BVf calculation. Conclusions: Using approved doses of Gd‐DOTA, the steady state RSS T 1 ‐signal in brain tissue is reached during the first pass and corresponds to the BVf. The first‐pass duration is sufficient to allow accurate BVf quantification. The RSS T 1 ‐method is appropriate for serial clinical studies since it allows fast and straightforward BVf quantification without arterial input function determination. This quantitative MRI method is particularly useful to assess the efficacy of antiangiogenic agents.