Magnetic resonance imaging of intracranial tumors: Intra-patient comparison of gadoteridol and ferumoxytol

This study aims to compare gadoteridol with ferumoxy-tol for contrast-enhanced and perfusion-weighted (PW) MRI of intracranial tumors. The final analysis included 26 patients, who underwent 3 consecutive days of 3T MRI. Day 1 consisted of anatomical pre-and postcon-trast images, and PW MRI was acquired using gadoter-idol (0.1 mmol/kg). On Day 2, the same MRI sequences were obtained with ferumoxytol (510 mg) and on Day 3, the anatomical images were repeated to detect delayed ferumoxytol-induced signal changes. The T ₁-weighted images were evaluated qualitatively and quantitatively for enhancement volume and signal intensity (SI) changes; PW data were used to estimate the relative cerebral blood volume (rCBV). All 26 lesions showed 24-hour T₁-weighted ferumoxytol enhancement; 16 also had T ₂-weighted hypointensities. In 6 patients, ferumoxytol-induced signal changes were noted in areas with no gadoteridol enhancement. Significantly greater (P <.0001) SI changes were seen with gadoteri-dol, and qualitative analyses (lesion border delineation, internal morphology, contrast enhancement) also showed significant preferences (P =.0121; P =.0015; P <.0001, respectively) for this agent. There was no significant difference in lesion enhancement volumes between contrast materials. The ferumoxytol-rCBV values were significantly higher (P =.0016) compared with the gadoteridol-rCBV values. In conclusion, feru-moxytol provides important information about tumor biology that complements gadoteridol imaging. The rCBV measurements indicate areas of tumor undergoing rapid growth, whereas the 24-hour scans mark the presence of inflammatory cells. Both of these functions provide useful information about tumor response to treatment. We suggest that dynamic and anatomical imaging with ferumoxytol warrant further assessment in brain tumor therapy.