Abstract 3725: Contrast Enhanced MRI with a Reduced Dose of Gadolinium for Measurement of Blood to Brain Influx Rate in Cerebrovascular Diseases
Dynamic Contrast-Enhanced MRI with a Reduced Dose of Gd-DTPA for Measurement of Blood-to-Brain Influx Rate in Cerebrovascular Diseases In vivo quantification of blood-to-brain transfer rate is of immense importance in diagnosis and monitoring cerebrovascular damages after stroke. Dynamic contrast-enhanced (DCE) methods in CT and MR have been used to collect data about the health of blood-brain barrier (BBB). However high dose of radiation in CT and high dose of contrast agent and long protocol time in MR limit the application of DCE methods in acute stroke imaging. The goal of this study was to investigate DCEMRI with a reduced dose of Gd-DTPA and reduced acquisition time for BBB quantification. Fifteen healthy subjects (23-85 years, 9M, 6F) were randomly divided into 4 groups. Each group received one of 4 different doses of Gd-DTPA (group I, 0.1mmol/Kg, n=4; group II, 0.05 mmol/Kg, n=4; group III, 0.025mmol/Kg, n=4; and group IV, 0.0125 mmol/kg, n=3) for DCEMRI. The MRI data acquisition was performed using a 1.5-Tesla Siemens whole-body scanner with a standard eight-channel array headcoil. Fast T1 sequence, TAPIR, was used to estimate the time-concentration of different doses of Gd-DTPA after IV bolus injection. In addition clinical laboratory data of time-dependent concentration of Gd-DTPA in plasma was obtained from contrast agent manufacturer. Clinical and MR-based data were analyzed for 1) nonlinearity effect of contrast on MR signal and 2) evaluate the percentage of MR sampling error. The reduced dose of Gd-DTPA was used to quantify the BBB transfer rate in 14 MS and 9 cerebral cavernous malformation patients recruited from other studies. Comparison of pharmaco dynamics of Gd-DTPA over a range of different initial doses (less than 0.1 mmol/Kg) shows that 1/4 of the standard dose renders less error in T1 sampling and provides a sufficient dynamics in the intensity of MR signal to achieve a shorter DCEMRI experiment. In comparison to the regular Gd-DTPA-enhanced images, the reduced dose of Gd-DTPA used in DCEMRI is more sensitive in BBB abnormality detection. Comparison of 4 different doses of Gd-DTPA showed that a dose of 25% of 0.1 mmol/Kg, when using a fast T1 mapping protocol, is optimal for BBB permeability quantification in patients. DCEMRI-based BBB influx rate measurements with reduced dose of contrast agent may offer a suitable and less risky biomarker for disease progression and drug trials. Imaging stroke; Left panel represent FLAIR anatomical image of patient with stroke. Right panel represents BBB transfer rate map.
- © 2012 by American Heart Association, Inc.