Comparison Of Perfusion Parameters Research Articles

Contrast-enhanced 3T MR Perfusion of Musculoskeletal Tumours: T1 Value Heterogeneity Assessment and Evaluation of the Influence of T1 Estimation Methods on Quantitative Parameters.

To evaluate intra-tumour and striated muscle T1 value heterogeneity and the influence of different methods of T1 estimation on the variability of quantitative perfusion parameters. Eighty-two patients with a histologically confirmed musculoskeletal tumour were prospectively included in this study and, with ethics committee approval, underwent contrast-enhanced MR perfusion and T1 mapping. T1 value variations in viable tumour areas and in normal-appearing striated muscle were assessed. In 20 cases, normal muscle perfusion parameters were calculated using three different methods: signal based and gadolinium concentration based on fixed and variable T1 values. Tumour and normal muscle T1 values were significantly different (p = 0.0008). T1 value heterogeneity was higher in tumours than in normal muscle (variation of 19.8% versus 13%). The T1 estimation method had a considerable influence on the variability of perfusion parameters. Fixed T1 values yielded higher coefficients of variation than variable T1 values (mean 109.6 ± 41.8% and 58.3 ± 14.1% respectively). Area under the curve was the least variable parameter (36%). T1 values in musculoskeletal tumours are significantly different and more heterogeneous than normal muscle. Patient-specific T1 estimation is needed for direct inter-patient comparison of perfusion parameters. • T1 value variation in musculoskeletal tumours is considerable. • T1 values in muscle and tumours are significantly different. • Patient-specific T1 estimation is needed for comparison of inter-patient perfusion parameters. • Technical variation is higher in permeability than semiquantitative perfusion parameters.

Perfusion CT in Colorectal Cancer: Comparison of Perfusion Parameters with Tumor Grade and Microvessel Density

ObjectiveThe purpose of this study was to prospectively compare pre-operative computed tomography (CT) perfusion parameters with tumor grade from colorectal adenocarcinoma (CRC) and to correlate pre-operative CT perfusion parameters with microvessel density (MVD) to evaluate angiogenesis in CRC.Materials and MethodsPre-operative perfusion CTs were performed with a 64-channel multidetector row CT in 27 patients (17 women and 10 men; age range 32-82 years) who were diagnosed with CRC involving the sigmoid and rectum between August 2006 and November 2007. All patients underwent surgery without pre-operative chemotherapy or radiation therapy. Dynamic perfusion CTs were performed for 65 seconds after intravenous injection of contrast medium (100 mL, 300 mg of iodine per mL, 5 mL/sec). Before surgery, blood flow (BF), blood volume, mean transit time (MTT), and permeability-surface area product were measured in the tumor. After surgery, one gastrointestinal pathologist evaluated tumor grade and performed immunohistochemical staining using CD 34 to determine MVD in each tumor. The Kruskal-Wallis test was used to compare CT perfusion parameters with tumor grade, and Pearson's correlation analysis was used to correlate CT perfusion parameters with MVD.ResultsIn 27 patients with CRC, tumor grading was as follows: well differentiated (n = 8); moderately differentiated (n = 15); and poorly differentiated (n = 4). BF was higher in moderately differentiated CRC than well differentiated and poorly differentiated CRCs (p = 0.14). MTT was shorter in moderately differentiated than well differentiated and poorly differentiated CRCs (p = 0.039). The MVD was greater in poorly differentiated than well differentiated and moderately differentiated CRCs (p = 0.034). There was no significant correlation between other perfusion parameters and tumor grade. There was no significant correlation between CT perfusion parameters and MVD.ConclusionBF and MTT measurement by perfusion CT is effective in predicting moderately differentiated CRCs. However, perfusion CT is limited in distinguishing well differentiated and poorly differentiated CRCs. Pre-operative perfusion CT does not reflect the MVD of CRCs.

Tumor vascular leakiness and blood volume estimates in oligodendrogliomas using perfusion CT: an analysis of perfusion parameters helping further characterize genetic subtypes as well as differentiate from astroglial tumors

The purpose of this study was to determine the usefulness of perfusion CT (PCT) parameters particularly blood volume and neovascular permeability estimates (permeability surface area-product, PS) in the evaluation of oligodendrogliomas (OG), correlation with genetic subtypes of OGs (with or without loss of heterozygosity/LOH on 1p/19q) as well as comparison of perfusion parameters of OGs with astroglial tumors. Pre-operative PCT done in 21 patients with OGs was retrospectively correlated with our previously published PCT data for 32 patients with astroglial neoplasms (Jain R et al., AJNR Am J Neuroradiol 29:694-700, 2008). All OGs were also analyzed for genetic subtypes of with or without LOH. PCT parameters PS and cerebral blood volume (CBV) were obtained for the entire lesion and a statistical analysis done to correlate various histopathological variants. Low grade OGs (n=13) showed slightly lower CBV (1.42 vs. 1.72ml/100g; P value 0.391) and PS (0.56 vs. 0.95ml/100g/min; P value 0.099) as compared to high grade OGs (n=8), though not statistically significant. LOH positive OGs (n=13) showed higher mean CBV (1.59 vs. 1.45; P value 0.712) and slightly lower PS (0.68 vs. 0.75; P value 0.718) as compared to LOH negative OGs (n=8), although not statistically significant. Low grade OGs (n=13) showed higher mean CBV 1.42ml/100g as compared to low grade astroglial tumors (n=8) 0.95ml/100g (P value=0.08), however no statistically significant difference was noted for PS (0.56 vs. 0.52ml/100g/min, P value 0.695). Statistically significant differences were observed in CBV and PS values of high grade OGs and high grade astroglial tumors with the high grade glial tumors showing higher mean CBV (2.79 vs. 1.72; P value 0.03) as well as higher PS (2.37 vs. 0.95; P value<0.01), however this difference was not significant if only comparing grade III OGs with grade III astroglial tumors. PCT perfusion parameters including PS values do not help grade OGs despite showing a trend for higher CBV and PS in higher grade OGs. Similarly LOH positive OGs also showed slightly higher CBV, but again failed to reach any statistically significant level. Low grade OGs showed slightly higher CBV as compared to low grade astroglial tumors, whereas higher grade OGs showed significantly lower PS values as compared to higher grade astroglial tumors despite showing high CBV.

SU‐FF‐I‐89: A Comparison of Perfusion Parameters From the Kinetic Modeling of Head and Neck Cancers in DCE CT

Purpose: While various kinetic models are used for estimating perfusion parameters from contrast‐enhanced CT scans, the difference amongst the model results are not well researched. The aim of this study was to determine the discrepancy between two of the most commonly used kinetic models: maximum‐slope and deconvolution. Methods: Seven patients with head and neck tumors underwent dynamic CT scans with an injected contrast agent. Contrast enhancement curves were obtained by segmenting arteries, veins, and tumor ROIs from the CT scans. The maximum‐slope model was used to calculate the blood flow, while the Patlak analysis interpolated the blood volume ratio and the permeability. The central volume theorem determined the mean transit time. These parameters were also generated via a deconvolution method implemented in the GE's Advantage Perfusion 4 software. Results: The mean population values of all parameters ‐ blood flow (BF), blood volume (BV), permeability (P) and mean transient time MTT) ‐ were similar between the maximum slope and deconvolution methods (BV: 116 vs 107 ml/100g/min, BV: 6.9 vs 7.9 ml/100g, P: 29 vs 20 ml/100g/min, MTT: 4.9 vs 7.3 s). However, on the individual patient level the difference were significant (BF difference: 70% ±60 %, BV difference: 35% ± 30%, P difference: 75% ± 60%. and MTT difference: 35% ± 25%. Conclusion: No significant differences were found amongst the mean population perfusion parameters. However, on the individual patient level, the differences were significant between the maximum slope and deconvolution‐based CT perfusion methods.

Pancreatic perfusion measurements using a 3d gradient-echo mri-sequence with bolus-injection of Gd-Dtpa: Comparison of perfusion parameters in normal volunteers and patients with chronic pancreatitis

Pancreatic perfusion measurements using a 3d gradient-echo mri-sequence with bolus-injection of Gd-Dtpa: Comparison of perfusion parameters in normal volunteers and patients with chronic pancreatitis