Spleen and splenic vascular involvement in acute pancreatitis: an MRI study

Abstract

Splenic vascular involvement and splenomegaly were common in AP. The vascular involvement was associated with the severity of AP. This complication should be considered when severity and prognosis of AP are assessed. Quantitative analysis of the spleen with IVIM might be a useful imaging biomarker for splenic perfusion changes in AP, especially in those with splenomegaly.

Early-phase vascular involvement is associated with acute pancreatitis severity: a magnetic resonance imaging study

“…We also observed that patients with splenic vein thrombosis determined in the late phase of AP showed signs of splenic vein phlebitis on their initial MRI scan. This new finding was probably due to early-phase vein inflammation, which eventually damages the endothelium, rendering the vessel susceptible to late-phase thrombosis (20,27). Also, patients with splenic vein thrombosis detected by initial MRI exhibited thrombus absorption on repeat MRI after treatment.…”

“…In addition, 44% of patients with splenic vein phlebitis had splenic vein stenosis in the early phase of AP. These new MRI findings may be explained by the close anatomic relationship between peripancreatic vasculatures and the pancreas itself, which results in local inflammatory spread and a weakened venous wall that is prone to collapse (17)(18)(19)(20). Interestingly, following treatment, the MRI signs of portosplenomesenteric vein phlebitis disappeared in most of these patients, suggesting that portosystemic vein phlebitis might be considered as a complementary sign for treatment evaluation.…”

MR imaging for acute pancreatitis: the current status of clinical applications

“…In acute pancreatitis, the spleen is also a commonly involved organ; common splenic abnormalities are splenomegaly and splenic infarction. In addition to routine sequences, quantitative analysis of the spleen with IVIM sequences might be useful for visualizing splenic perfusion changes in AP (14).…”

“…Studies have shown that MRI can display positive correlations between the time of improvement of the gastrointestinal tract abnormalities and the time of hospitalization, the disappearance time of abdominal pain and abdominal distention, and the normal time of amylase recovery and the recovery time of the diet (47). MRI can also show peripancreatic vascular changes, and the severity of vascular involvement is positively correlated with the severity of AP (14). In addition, the incidence of liver and kidney dysfunction, pulmonary inflammation, perirenal space involvement, interfascial plane involvement and abdominal wall edema increases with the severity of AP (50)(51)(52).…”

“…As an alternate method for diagnosing acute pancreatitis, MR imaging (MRI) and MR cholangiopancreatography (MRCP) shows great potential in clinical applications (7). The benefits of MRI for acute pancreatitis are as follows: (I) the MRI sequence for T2-weighted image (T2WI) is highly sensitive to liquid and thus can visualize a small amount of liquid in mild pancreatitis, T2WI can characterize non-liquid materials in the pancreatic collections better than CT (6); (II) MRI clearly shows the areas of necrosis without enhancement and is safe for patients who are unable to receive iodinated contrast material because of allergies or kidney failure (8,9); (III) MRCP can noninvasively evaluate the changes of the bile ducts (especially the distal bile duct, which is difficult for ultrasound to show) and pancreatic duct system and help diagnose the etiology of the disease (10); (IV) recent studies have found that in addition to the air bubbles, high signals on the MRI diffusion-weighted imaging (DWI) sequences can also indicate the existence of infection to preliminarily determine whether the accumulation is infected (11); (V) novel MRI techniques such as intravoxel incoherent motion (IVIM) imaging can assess both perfusion and diffusion of the diseased tissues (12)(13)(14); (VI) MRI can be used to stage AP and clearly show local complications. It has been reported that non-enhanced MRI is more reliable and accurate than CT in estimating the severity of AP (9); and (VII) finally, MRI does not require ionizing radiation and does not lead to adverse effects on the human body.…”