RESUMO
Introduction: 1.5 Tesla (1.5T) remain a significant field strength for brain imaging worldwide. Recent computer simulations and clinical studies at 3T MRI have suggested that dynamic susceptibility contrast (DSC) MRI using a 30° flip angle ("low-FA") with model-based leakage correction and no gadolinium-based contrast agent (GBCA) preload provides equivalent relative cerebral blood volume (rCBV) measurements to the reference-standard acquisition using a single-dose GBCA preload with a 60° flip angle ("intermediate-FA") and model-based leakage correction. However, it remains unclear whether this holds true at 1.5T. The purpose of this study was to test this at 1.5T in human high-grade glioma (HGG) patients. Methods: This was a single-institution cross-sectional study of patients who had undergone 1.5T MRI for HGG. DSC-MRI consisted of gradient-echo echo-planar imaging (GRE-EPI) with a low-FA without preload (30°/P-); this then subsequently served as a preload for the standard intermediate-FA acquisition (60°/P+). Both normalized (nrCBV) and standardized relative cerebral blood volumes (srCBV) were calculated using model-based leakage correction (C+) with IBNeuro™ software. Whole-enhancing lesion mean and median nrCBV and srCBV from the low- and intermediate-FA methods were compared using the Pearson's, Spearman's and intraclass correlation coefficients (ICC). Results: Twenty-three HGG patients composing a total of 31 scans were analyzed. The Pearson and Spearman correlations and ICCs between the 30°/P-/C+ and 60°/P+/C+ acquisitions demonstrated high correlations for both mean and median nrCBV and srCBV. Conclusion: Our study provides preliminary evidence that for HGG patients at 1.5T MRI, a low FA, no preload DSC-MRI acquisition can be an appealing alternative to the reference standard higher FA acquisition that utilizes a preload.
RESUMO
BACKGROUND: Despite a proliferation of technological advances in sinonasal surgery, "cold steel" instruments still comprise the core of the sinus surgeon's tools of the trade. Many of these implements retain eponyms that recall the legacies of prominent surgeons of the past. OBJECTIVE: This review aims to familiarize the reader with the lives of 10 men who designed and popularized some of the most recognizable sinus instruments, without which the practice of rhinologic surgery would be unrecognizable. RESULTS: Ten individuals whose inventions are still used to this day and retain their names: Hartmann, Killian, Freer, Blakesley, Weil, Frazier, Grünwald, Hajek, Takahashi, and Cottle. CONCLUSION: Review of the history of these instruments helps demonstrate how sinus surgery has evolved to where it is today. The men described in this review transformed the practice of rhinologic surgery with their ingenuity and perseverance.