New Insights in Abdominal Pain in Paroxysmal Nocturnal Hemoglobinuria (PNH): A MRI Study

INTRODUCTION: Abdominal pain in PNH has never been investigated by in-vivo imaging studies. With MRI, we aimed to assess mesenteric vessels flow and small bowel wall perfusion to investigate the ischemic origin of abdominal pain. MATERIALS AND METHODS: Six PNH patients with (AP) and six without (NOP) abdominal pain underwent MRI. In a blinded fashion, mean flow (MF, quantity of blood moving through a vessel within a second, in mL·s(-1)) and stroke volume (SV, volume of blood pumped out at each heart contraction, in mL) of Superior Mesenteric Vein (SMV) and Artery (SMA), areas under the curve at 60 (AUC(60)) and 90 seconds (AUC(90)) and K(trans) were assessed by two operators. RESULTS: Mean total perfusion and flow parameters were lower in AP than in NOP group. AUC(60): 84.81 ± 11.75 vs. 131.73 ± 18.89 (P < 0.001); AUC(90): 102.33 ± 14.16 vs. 152.58 ± 22.70 (P < 0.001); K(trans): 0.0346 min(-1) ± 0.0019 vs. 0.0521 ± 0.0015 (P = 0.093 duodenum, 0.009 jejunum/ileum). SMV: MF 4.67 ml/s ± 0.85 vs. 8.32 ± 2.14 (P = 0.002); SV 3.85 ml ± 0.76 vs. 6.55 ± 1.57 (P = 0.02). SMA: MF 6.95 ± 2.61 vs. 11.2 ± 2.32 (P = 0.07); SV 6.52 ± 2.19 vs. 8.78 ± 1.63 (P = 0.07). We found a significant correlation between MF and SV of SMV and AUC(60) (MF:ρ = 0.88, P < 0.001; SV: ρ = 0.644, P = 0.024), AUC(90) (MF: ρ = 0.874, P < 0.001; SV:ρ = 0.774, P = 0.003) and K(trans) (MF:ρ = 0.734, P = 0.007; SV:ρ = 0.581, P = 0.047). CONCLUSIONS: Perfusion and flow MRI findings suggest that the impairment of small bowel blood supply is significantly associated with abdominal pain in PNH.