CT-perfusion measurements in pancreatic carcinoma with different kinetic models: Is there a chance for tumour grading based on functional parameters?

Abstract

BackgroundTo evaluate the interchangeability of perfusion parameters obtained with help of models used for post-processing of perfusion-CT images in pancreatic adenocarcinoma and to determine the mean values and ranges of perfusion in different tumour gradings.MethodsPerfusion-CT imaging was performed prospectively in 48 consecutive patients with pancreatic adenocarcinoma. In 42 patients biopsy-proven tumor grading was available (4 × G1/24 × G2/14 × G3/6× unknown). Images were post-processed using a model based on the maximum-slope (MS) approach (blood flow-BFMS) + Patlak analysis (P) (blood volume [BVP] and permeability [k-transP]), as well as a model with deconvolution-based (D) analysis (BFD, BVD and k-transD). 50 mL contrast agent were applied with a delay time of 7 s. Perfusion parameters were compared using intraclass correlation coefficient (ICC), the Wilcoxon matched-pairs test and Bland-Altman plots.ResultsForty eight VOIs of tumours were outlined and analysed. Moderate to good ICC values were found for the perfusion parameters (ICC = 0.62–0.75). Wilcoxon matched-pairs revealed significantly lower values (P < .001 and 0.008), for the BF and BV values obtained using the maximum-slope approach + Patlak analysis compared to deconvolution based analysis. For k-trans measurement, deconvolution revealed significantly lower values (P < 0.001). Different histologic subgroups (G1-G3) did not show significantly different functional parameters.ConclusionThere were significant differences in the perfusion parameters obtained using the different calculation methods, and therefore these parameters are not directly interchangeable. However, the magnitude of pairs of parametric values is in constant relation to each other enabling the use of any of these methods. VPCT parameters did not allow for histologic classification.

Assessment of tissue perfusion of pancreatic cancer as potential imaging biomarker by means of Intravoxel incoherent motion MRI and CT perfusion: correlation with histological microvessel density as ground truth

“…We used the deconvolution model for CT perfusion analysis since it can tolerate greater image noise than compartment models and was reported to be well suited for measuring lower levels of perfusion [ 33 ], as expected in PDAC. The deconvolution-based BF tumor values obtained in our current study were similar to previously reported deconvolution-based BF tumor values in PDAC [ 34 ], but considerably higher than previously reported BF tumor values based on the maximum-slope approach in PDAC [ 34 , 35 ]. This difference between BF tumor values obtained from the different models might be attributable to differences in the two mathematical calculation methods [ 34 ].…”

“…The deconvolution-based BF tumor values obtained in our current study were similar to previously reported deconvolution-based BF tumor values in PDAC [ 34 ], but considerably higher than previously reported BF tumor values based on the maximum-slope approach in PDAC [ 34 , 35 ]. This difference between BF tumor values obtained from the different models might be attributable to differences in the two mathematical calculation methods [ 34 ]. Mean BV tumor and PEM tumor values were within the same range as those reported by Schneeweiß et al [ 34 ].…”

“…This difference between BF tumor values obtained from the different models might be attributable to differences in the two mathematical calculation methods [ 34 ]. Mean BV tumor and PEM tumor values were within the same range as those reported by Schneeweiß et al [ 34 ]. Also, mean values of the DWI IVIM parameters, as well as the histological microvessel parameters were within the same range as in a previous study by Klauß et al [ 19 ].…”

CT perfusion and diffusion-weighted MR imaging of pancreatic adenocarcinoma: can we predict tumor grade using functional parameters?

“…In contrast, Schneeweiss et al. (14) found no significant differences in perfusion parameters between different grades of pancreatic adenocarcinomas. Nevertheless, in the abovementioned study there were three groups of patients based on histological differentiation (G1–G3), while in the current study well- and moderately differentiated tumors were combined as one group because of rarity of well-differentiated tumors and due to similarity of their prognosis.…”

The feasibility of low-concentration contrast and low tube voltage in computed tomography perfusion imaging: an animal study

“…This technique has been widely employed in the quantitative analysis of acute ischemic stroke in the brain [1][2][3]. As post-processing strategies and software have developed, the application of CTPI has expanded to more settings, including the assessment of hepatic and pancreatic lesions [4][5][6][7][8][9][10]. Specifically, liver CTPI has been shown to provide valuable information for the diagnosis and prognosis of liver diseases such as hepatic cirrhosis, hepatocellular carcinoma, and cancer metastasis to the liver [7][8][9][10][11][12][13][14].…”