Apparent diffusion coefficient in pancreatic cancer: Characterization and histopathological correlations

Abstract

Purpose To clarify the components primarily responsible for diffusion abnormalities in pancreatic cancerous tissue. Materials and Methods Subjects comprised 10 patients with surgically confirmed pancreatic cancer. Diffusion‐weighted (DW) echo‐planar imaging (b value = 0, 500 s/mm2) was employed to calculate the apparent diffusion coefficient (ADC). ADC values of cancer and noncancerous tissue were calculated. Furthermore, ADC values of the cancer were compared with histopathological results. Results The mean (±standard deviation) ADC value was significantly lower for tumor (1.27 ± 0.52 × 10−3 mm2/s) than for noncancerous tissue (1.90 ± 0.41 × 10−3 mm2/s, P < 0.05). Histopathological examination showed similar proportions of fibrotic area, cellular component, necrosis, and mucin in each case. Regarding the density of fibrosis in cancer, three cases were classified in the loose fibrosis group and the remaining seven cases were classified in the dense fibrosis group. The mean ADC value was significantly higher in the loose fibrosis group (1.88 ± 0.39 × 10−3 mm2/s) than in the dense fibrosis group (1.01 ± 0.29 × 10−3 mm2/s, P < 0.05). In quantitative analysis, ADC correlated well with the proportion of collagenous fibers (r = −0.87, P < 0.05). Conclusion Collagenous fibers may be responsible for diffusion abnormalities in pancreatic cancer. J. Magn. Reson. Imaging 2008;27:1302–1308. © 2008 Wiley‐Liss, Inc.

A Pilot Study of Diffusion-Weighted MRI in Patients Undergoing Neoadjuvant Chemoradiation for Pancreatic Cancer

“…Another report found a correlation between preoperative ADC values and the amount of tumor fibrosis in patients who did not receive preoperative therapy. Tumors with a low ADC were found to be densely fibrotic [23]. The large amount of fibrotic tissue in pancreatic tumors may limit the delivery of radiosensitizing systemic therapy and lower the amount of oxygen available for radiation induced free radical formation thereby decreasing the effectiveness of chemoradiation therapy [24].…”

Apparent diffusion coefficient measurements of the pancreas, pancreas carcinoma, and mass-forming focal pancreatitis

“…However, the use of a the thin slice thickness and two b values did allow a rapid acquisition of images, albeit at a low signal to noise ratio (SNR) of DWI images and thus influencing the ADC values. PC has been associated with decreased ADC values compared to healthy pancreatic tissue due to the presence of fibrosis and increased cellularity which is associated with restricted water diffusion (13). Necrosis is a common feature of PC and is associated with increased ADC values due to increased motion of the water protons in the tissue (21).…”

“…Diffusion-weighted MRI and apparent diffusion coefficient (ADC) measurements have been applied to the abdomen (2)(3)(4)(5). The results suggest that ADC measurements can be useful in the evaluation of diffuse liver (6) and renal diseases (7,8) as well as for characterizing focal hepatic (4, 9), pancreatic (10)(11)(12)(13)(14)(15), and renal (16) lesions. The purpose of our study was to evaluate DWI findings and measure the difference between ADC values of normal pancreas parenchyma, mass-forming focal pancreatitis (FP) and pancreas carcinoma (PC).…”

Diffusion weighted MRI for detecting and monitoring cancer: a review of current applications in body imaging

“…When the tumor consists of prominent loose extracellular fibrosis (edematous fibrosis and loose collagen fibers) with a reduced cellular component, the ADC values are higher than in the normal pancreas. When there is a dense fibrosis and increased cellular elements, the ADC values are lower than in the normal pancreas (71). Pancreatic adenocarcinoma demonstrates restricted diffusion in DWI compared with the rest of the gland, with a high b value (1 000 s/mm 2 ).…”