Pulmonary embolism after a long-haul flight.

The relation between long-haul flights (LHF) and venous thromboembolic disease is well established. Nonetheless, the incidence of pulmonary embolisms after these flights is probably underestimated because of the difficulties in case ascertainment. Reunion Island appears to present the ideal geographic conditions for accurately assessing this incidence. We aimed to assess the incidence of pulmonary embolisms in people who had recently taken a LHF to Reunion Island. We conducted a retrospective multi-center descriptive study and included all cases of pulmonary embolisms diagnosed between January 1, 2015, and January 30, 2017 (according to the hospitals' discharge summary database) in the island's four public hospitals within 30 days after taking an LHF to Reunion. We took different delays of diagnosis to calculate the incidence. We have considered the time to diagnosis at 1 month as significant according to the time applied in the Geneva score for risk factors. The study included 45 patients landing on Reunion over a 2-year period. The total number of passengers arriving by LHF during this period was 1,223,001. The incidence of pulmonary embolism after an LHF was thus calculated at 36.8 per million travelers at 1 month. The incidence for PE diagnosed, after 15 days was 29.4 per million travelers, and after 7 days, it was 21.9 per million travelers. The male/female ratio was 0.67. The mean interval between the flight and symptom onset was 7 days. In our population, the incidence of pulmonary embolisms after LHFs in our study is clearly higher than that reported in the literature (36.8 vs 4.8). Our exhaustive data collection probably explains this difference. A case-control study appears necessary to analyze the risk factors for pulmonary embolism after a LHF.

T1-weighted dynamic contrast-enhanced brain magnetic resonance imaging: A preliminary study with low infusion rate in pediatric patients.

Background The aim of this preliminary study is to evaluate the results of T1-weighted dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) in pediatric patients at 1.5T, with a low peripheral intravenous gadoteric acid injection rate of 1 ml/s. Materials and methods Children with neurological symptoms were examined prospectively with conventional MRI and T1-weighted DCE MRI. An magnetic resonance perfusion analysis method was used to obtain time-concentration curves (persistent pattern, type-I; plateau pattern, type-II; washout pattern, type-III) and to calculate pharmacokinetic parameters. A total of two radiologists manually defined regions of interest (ROIs) in the part of the lesion exhibiting the greatest contrast enhancement and in the surrounding normal or contralateral tissue. Lesion/surrounding tissue or contralateral tissue pharmacokinetic parameter ratios were calculated. Tumors were categorized by grade (I-IV) using the World Health Organization (WHO) Grade. Mann-Whitney testing and receiver-operating characteristic (ROC) curves were performed. Results A total of nine boys and nine girls (mean age 10.5 years) were included. Lesions consisted of 10 brain tumors, 3 inflammatory lesions, 3 arteriovenous malformations and 2 strokes. We obtained analyzable concentration-time curves for all patients (6 type-I, 9 type-II, 3 type-III). Ktrans between tumor tissue and surrounding or contralateral tissue was significantly different ( p = 0.034). Ktrans ratios were significantly different between grade I tumors and grade IV tumors ( p = 0.027) and a Ktrans ratio value superior to 0.63 appeared to be discriminant to determine a grade IV of malignancy. Conclusions Our results confirm the feasibility of pediatric T1-weighted DCE MRI at 1.5T with a low injection rate, which could be of great value in differentiating brain tumor grades.