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Quantitative Perfusion-Weighted Magnetic Resonance Imaging in Uveal Melanoma. | LitMetric

AI Article Synopsis

  • The study investigates a new quantitative perfusion-weighted imaging (PWI) method for assessing blood flow in uveal melanoma, which could offer a more accurate analysis than existing semiquantitative techniques that don’t account for pigmentation or eye movement.
  • Researchers analyzed 47 patients’ MRIs before and after radiotherapy, using Tofts pharmacokinetic modeling to measure tumor vascular parameters, finding significant differences in perfusion metrics related to tumor pigmentation.
  • Results suggest that the new quantitative PWI parameters effectively indicate treatment response after radiotherapy, while the traditional semiquantitative methods remain valid due to the minimal changes observed in tumor pigmentation.

Article Abstract

Purpose: Perfusion-weighted imaging (PWI; magnetic resonance imaging [MRI]) has been shown to provide valuable biological tumor information in uveal melanoma (UM). Clinically used semiquantitative methods do not account for tumor pigmentation and eye movement. We hypothesize that a quantitative PWI method that incorporates these, provides a more accurate description of tumor perfusion than the current clinical method. The aim of this study was to test this in patients with UM before and after radiotherapy.

Methods: Perfusion-weighted 3T MRIs were retrospectively analyzed in 47 patients with UM before and after radiotherapy. Tofts pharmacokinetic modeling was performed to determine vascular permeability (Ktrans), extracellular extravascular space (ve), and reflux rate (kep). These were compared with semiquantitative clinical parameters including peak intensity and outflow percentage.

Results: The effect of tumor pigmentation on peak intensity and outflow percentage was statistically significant (P < 0.01) and relative peak intensity was significantly different between melanotic and amelanotic tumors (1.5 vs. 1.9, P < 0.01). Before radiotherapy, median tumor Ktrans was 0.63 min-1 (range = 0.06-1.42 min-1), median ve was 0.23 (range = 0.09-0.63), and median kep was 2.3 min-1 (range = 0.6-5.0 min-1). After radiotherapy, 85% showed a decrease in Ktrans and kep (P < 0.01). Changes in tumor pigmentation before and after radiotherapy were small and not significant (median increase in T1 of 33 ms, P = 0.55).

Conclusions: Quantitative PWI parameters decreased significantly after radiotherapy and can therefore can serve as an early biomarker for treatment response assessment. However, due to the nonsignificant changes in tumor pigmentation before and after radiotherapy, the current semiquantitative method appears to be sufficiently sensitive for detection of changes in tumor perfusion.

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Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC11385876PMC
http://dx.doi.org/10.1167/iovs.65.11.17DOI Listing

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