Sergio Margari MD, Presenter: Nothing to Disclose

Francesco Aldo De Cobelli MD, Abstract Co-Author: Nothing to Disclose

Giulio Pezzetti MD, Abstract Co-Author: Nothing to Disclose

Antonio Esposito MD, Abstract Co-Author: Nothing to Disclose

Alessandro Del Maschio MD, Abstract Co-Author: Nothing to Disclose

The exact pathogenesis of abdominal pain in patients with Paroxysmal Nocturnal Hemoglobinuria (PNH) has never been investigated by in-vivo imaging studies. We aimed to use Magnetic Resonance Imaging (MRI) for an accurate assessment of mesenteric vessels flow and small bowel microvascular perfusion, in order to identify early pathophysiological phenomena associated with abdominal pain in PNH patients.

Twelve PNH patients, six with abdominal pain (AP) and six without abdominal pain (NOP), underwent MRI in fasting conditions. Mean flow (MF) and stroke volume (SV) of Superior Mesenteric Vein (SMV) and Artery (SMA) were measured with ECG-gated phase-contrast flow-mapping sequences; mean areas under the curve at 60 (AUC60) and 90 seconds (AUC90) and Ktrans of the small intestine wall were assessed using Dynamic Contrast Enhanced MRI (DCE-MRI). Statistics were performed with Mann-Whitney test, Spearman's correlation and linear regression model.  

All MRI parameters were lower in AP than in NOP. Total AUC60: 84.81 ± 11.75 vs. 131.73 ± 18.89 (P < 0.001); total AUC90: 102.33 ± 14.16 vs. 152.58 ± 22.70 (P < 0.001); total Ktrans: 0.0346 ± 0.0019 min-1 vs. 0.0521 ± 0.0015 (P = 0.093 duodenum, 0.009 jejunum, 0.009 ileum). SMV: MF 4.67 ± 0.85 ml/s vs. 8.32 ± 2.14 (P = 0.002); SV 3.85 ± 0.76 ml vs. 6.55 ± 1.57 (P = 0.02). MF in SMV showed a positive correlation with total AUC60 (Spearman ρ = 0.882, P < 0.001), total AUC90 (ρ = 0.855, P = 0.001) and total Ktrans (ρ = 0.764, P = 0.006); linear regression analysis showed that MF in SMV was able to explain about 60-70% of MRI perfusion variability in the whole small intestine (R2 = 0.607, P = 0.005 total AUC60; R2 = 0.668, P = 0.002 total AUC90; R2 = 0.731, P = 0.011 total Ktrans). SMA: MF 6.95 ± 2.61 ml/s vs. 11.2 ± 2.32; SV 6.52 ± 2.19 ml vs. 8.78 ± 1.63 (P =0.07).      

Combined MR based assessment of blood flow in the mesenteric vessels and small intestine wall perfusion suggests that an impairment of small bowel blood supply is associated with the presence of abdominal pain in PNH patients. Comparing flow and perfusion parameters, MF in SMV resulted the most powerful small bowel wall perfusion independent predictor.

Small intestine blood flow and perfusion impairment, especially in the venous compartment and in jejunum and ileum, seems to be an early/reliable MRI marker of mesenteric ischemia in untreated PNH patients with abdominal pain.

Margari, S, De Cobelli, F, Pezzetti, G, Esposito, A, Del Maschio, A, Dynamic Contrast-Enhanced Magnetic Resonance Imaging of Small Bowel and Magnetic Resonance Flow Analysis of Mesenteric Vessels in Patients with Paroxysmal Nocturnal Hemoglobinuria with and without Abdominal Pain.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14003197.html