Diffusion-weighted magnetic resonance imaging indicates the severity of acute pancreatitis

Abstract

DW-MRI was a compatible and safe image option to differentiate tissue image patterns in patients with mAP, nAP, and nP, mainly in those with contraindications to contrast-enhanced MRI (which is classically required for determining the presence of necrosis) or computed tomography. ADC measures allowed precise differentiation between patterns 1, 2, and 3.

Prospective Assessment of Variability and Reproducibility of Diffusion-Weighted MRI and T2-Mapping of the Pancreas in Healthy Volunteers

“…are present likely arise from the wide range of data acquisition and analysis procedures implemented. For example, while more than two b-values were utilized in some studies [3,16], including the current one, others estimated ADCs using just 2 b-values (e.g., 0 and 800 secs/mm 2 ) [19,22]. The presence of intravoxel incoherent motion in DW-MRI data and how this effect was or was not accounted may have also influenced computed ADC values, particularly when low b-values were utilized [26].…”

“…For longitudinal investigation of the diseased pancreas, where multiple imaging evaluations are needed within a short timeframe, MRI has the added value over CT given the lack of substantial radiation exposure or need for exogenous contrast agents that enable identification of pancreatic pathology. To date, MRI methods, mainly diffusion-weighted MRI (DW-MRI) and T2-MRI, have shown sensitivity for detecting pathology in acute or chronic pancreatitis [3][4][5][6][7], autoimmune pancreatitis [8][9][10] and pancreatic cancer [11][12][13].…”

“…Such intracellular, extracellular and intravascular pathological events modulate microstructural properties of affected pancreatic tissue, and in turn, alter the random Brownian motion of water molecules in each biological compartment. From DW-MRI experiments aimed at measuring apparent diffusion coefficients (ADCs), it is known that inflammatory compared to healthy pancreatic tissue is characterized as having restricted water diffusion (decreased ADCs), while less restricted water diffusion (increased ADCs) occurs in necrotic lesions [3,11]. With respect to T2-MRI signals, presence of inflammatory infiltrates and parenchymal changes can be identified by regions of increased T2-weighted signal intensities or prolonged T2-relaxation times [5].…”

Recent Advances in Pancreatic MR Imaging: A Guide on How, When, and Why to Perform

“…The average ADC of acute pancreatitis is reported to be approximately 1.2-1.6 × 10 -3 mm 2 /s depending on the severity of pancreatitis. 32,33 ADC values are shown to correlate with the Balthazar score of severity of pancreatitis with lower values representing a higher score. 34 DWI can be used to identify mild acute interstitial pancreatitis especially in patients in whom contrast study cannot be done 35 (►Fig.…”

“…With successful treatment of pancreatitis, ADC values are shown to normalize. 36 Caution should be exercised in presence of necrotizing pancreatitis, as the necrotic area may show higher ADC values and lower signal on DWI due to loss of cell membrane integrity ("facilitated diffusion") 32 (►Fig. 9).…”