No abstract

The new classification is useful for describing the imaging features of isolated dissection of the SMA.

BACKGROUND AND PURPOSE:Gadobenate dimeglumine has markedly higher R1 relaxivity compared to gadopentetate dimeglumine meaning that lower doses can be used to achieve similar contrast enhancement. Our aim was to prospectively compare single-dose gadobenate dimeglumine with double-dose gadopentetate dimeglumine for contrast-enhanced MRA of the supra-aortic vasculature.

Isolated superior mesenteric artery dissection (SMAD) is a pleiomorphic disease. A systematic approach requires adequate classification. The purpose of classification is to organize patients into groups, which should be clinically informative in order to assist medical decision making. Four classification systems, which were all devised based on the imaging appearance of the SMAD, have been proposed over recent years; 1e4 however, no consensus has emerged regarding which classification system should be used. Sakamoto et al. 1 categorized SMAD into four types. However, they did not consider the type of total thrombotic occlusion of the SMA. Yun et al. 2 categorized SMAD into three types, but they did not consider thrombosed false lumen with ulcer-like projection. Zerbib et al. 3 categorized SMAD into six types. However, SMAD with retrograde propagation of the false lumen to the SMA ostium wasn't addressed. Luan and Li 4 categorized SMAD into four types, but they did not consider the true and the false lumen itself, such as the shape, the thrombosed false lumen, and stenosis of the true lumen. The main anatomic and physio-pathologic features of SMADs are the location, extent of the false lumen, and the distinction between thrombosed or not false and true lumen. All four classification systems take into account some of these anatomic features. However, they are all incomplete. What we need is a simple system that allows exhaustive description of all anatomic types of SMADs and meets both the capabilities of modern imaging techniques and the demands of an ever-growing treatment armamentarium.

Sixteen patients were accrued to the phase I dose escalating (range 51w63GyE in 17w21 fractions) protocol. No patient experienced grade 4 toxicities, thus the MTD was set at 63 GyE/21 fractions, the highest of the protocol dose scheme. Thirty-nine LR-NPC patients (AJCC stage I/II/III/IVA-B disease in 4/8/10/17 patients) were accrued to the phase II study. All patients completed planned 63GyE/21 daily fractions without break. With a median follow-up of 8.4 (range 2.0w21.9) months, 1 patient died from massive hemorrhage subsequent to mucosal necrosis. The 1-year overall, local progression-free, regional recurrence-free, and distant metastasis free survival rates were 95.0%, 87.1%, 96.4%, and 100%, respectively. No patient experienced acute toxicity of grade 3. Grade 3 or above late toxicities observed included mucosal necrosis (5.1%), xerostomia (2.6%), hearing loss (5.1%), and temporal lobe necrosis (2.6%). Conclusion: This was the first prospective clinical trial to evaluate the efficacy and safety of CIRT for LR-NPC. Our results suggested that CIRT provided promising OS at 1 year with infrequent severe toxicities.