A preliminary study published in Academic Radiology March 15 suggests dynamic contrast-enhanced MRI (DCE-MRI) can add value to the diagnosis of acute pancreatitis (AP) while subverting the use of perfusion CT, potentially paving the way for more irradiation-free analysis.
Perfusion CT is the modality of choice for some physicians looking to estimate the severity of a patient’s AP at an early stage and help predict the progression of pancreatic necrosis, Ran Hu, MS, and co-authors wrote in the journal. But it also requires intravenous injection of a possibly nephrotoxic iodinated medium and guarantees exposure to irradiation.
That’s where DCE-MRI comes into play, the authors said—as a safer alternative to X-rays or CT for assessing perfusion.
“DCE-MRI depends on acquiring a rapid sequence of images with high temporal resolution to analyze the relaxation effects of the contrast agent over the dynamic data-acquisition timeframe and to provide quantitative estimates of the physiological parameters associated with perfusion and/or permeability in vivo,” Hu et al. wrote. “Based on the pharmacokinetic model applied to fit the contrast-enhanced curves, quantitative parameters can be derived that reflect the vascular and structural characteristics of the target tissue.”
The researchers analyzed images from 81 AP patients and 26 normal subjects who underwent DCE-MRI, paying particular attention to perfusion parameters like the volume transfer coefficient (K-trans), plasma volume (PV) and area under the curve (AUC). Pancreatic parameters were compared between AP patients and controls, and in AP patients parameters were compared between edematous and necrotizing pancreatitis and among different grades of AP severity.
Hu and colleagues found K-trans, PV and AUC values were all lower in AP patients than in controls. Based on the MR severity index (MRSI), K-trans and AUC values were significantly different between mild and moderate AP and between mild and severe diagnoses, but not between moderate and severe AP. K-trans numbers were also significantly different between edematous and necrotizing pancreatitis.
“Pancreatic perfusion is significantly lower in AP patients than in patients with a normal pancreas, and pancreatic perfusion tends to decrease as the severity of AP increases,” the authors wrote. “In this study, DCE-MRI can be applied to differentiate between an AP and a normal pancreas, and the K-trans, PV and AUC values can be used as indicators to predict the severity of AP, which makes a significant difference in promoting timely treatment and improving patient prognosis.”