Quantitative analysis of diffusion‐weighted magnetic resonance imaging of the pancreas: Usefulness in characterizing solid pancreatic masses

Abstract

Purpose:To evaluate whether measurement of apparent diffusion coefficient (ADC) and pure diffusion coefficient (D) can help to characterize solid pancreatic masses. Materials and Methods:Diffusion-weighted MR imaging was performed in both a patient group (n ϭ 71; pancreatic cancer [n ϭ 47], mass-forming pancreatitis [n ϭ 13], solid pseudopapillary neoplasm [n ϭ 6], and neuroendocrine tumor [n ϭ 5]) and a normal control group (n ϭ 11) by applying three b-factors of 0, 500, and 1000 sec/mm 2 . ADC 500 , ADC 1000 , D (ADC using b ϭ 500 and 1000 sec/mm 2 ), and perfusion fraction (f, 1-exp [-500 sec/mm 2 ϫ (ADC 500 -D)]) of normal pancreas, pancreatic cancer, and mass-forming pancreatitis were compared using the Kruskal-Wallis test. Receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic performance and optimal cutoff value of these parameters in differentiating pancreatic cancer from mass-forming pancreatitis.Results: Normal pancreas had significantly higher mean ADC 500 , ADC 1000 , and f than either pancreatic cancer (P Ͻ 0.001, Ͻ 0.001, and 0.004, respectively) or mass-forming pancreatitis (P Ͻ 0.001, Ͻ 0.001, and 0.002, respectively). ADC 500 , ADC 1000 , and D of mass-forming pancreatitis were significantly lower than those of pancreatic cancer (P ϭ 0.002, 0.004, and 0.014, respectively). Sensitivities and specificities in the diagnosis of pancreatic cancer were 72.3% and 76.9% for ADC 500 , 87.2% and 69.2% for ADC 1000 , 87.2% and 61.5% for D, and 42.6% and 92.3% for f, respectively. Conclusion:Measurement of ADC and D may be helpful in differentiating pancreatic cancers from mass-forming pancreatitis.

Imaging of gastroenteropancreatic neuroendocrine tumors

“…In the study by Liapi et al [40] , ADC values rose concomitantly with response to transarterial chemoembolization (TACE), in tandem with decreased enhancement of the treated lesions. For the primary lesions, DWI may allow for preoperative localization of tumors in the pancreas, especially those which do not demonstrate the typical hypervascular pattern [41,42] .…”

The effect of gadoxetic acid enhancement on lesion detection and characterisation usingT2weighted imaging and diffusion weighted imaging of the liver

“…The same radiologist performed the ROI measurement of the ADC values of the target lesions on DW images using MATLAB-based software (blinded), which automatically calculates ADC values of the areas within manually drawn ROIs [18]. For each target lesion, the ROI was placed in the same manner as the ROI measurement of the SI of the target lesion.…”

Decreased Blood Flow with Increased Metabolic Activity: A Novel Sign of Pancreatic Tumor Aggressiveness

“…Park et al (25) observed that high perfusion in pancreatic cancer detected on DCE-CT was associated with increased response to chemoradiotherapy. Also, the role of DCE magnetic resonance imaging has evolved in the field of perfusion imaging, and several groups have used it in evaluating the perfusion of benign and malignant pancreatic lesions (10,(26)(27)(28). Nevertheless, [ 15 O]H 2 O PET has been studied more extensively than either DCE-CT or magnetic resonance imaging, and is regarded by some authors as a gold standard in perfusion imaging (15).…”