Cross-modality and in-vivo validation of 4D flow MRI evaluation of uterine artery blood flow in human pregnancy

OBJECTIVES

Clinical assessment of uterine artery (UtA) hemodynamics is currently limited to Doppler ultrasound (US) velocimetry. We have demonstrated previously the feasibility of applying four-dimensional (4D) flow magnetic resonance imaging (MRI) to evaluate UtA hemodynamics during pregnancy, allowing flow quantification of the entire course of the vessel. In this study, we sought to further validate the physiological relevance of 4D flow MRI measurement of UtA blood flow by exploring its association with pregnancy outcome relative to US-based metrics.

METHODS

Recruited into this prospective, cross-sectional study were 87 women with a singleton pregnancy who underwent 4D flow MRI between May 2016 and April 2019 to measure the UtA pulsatility index (MRI-PI) and blood flow rate (MRI-flow, in mL/min). UtA-PI was also measured using US (US-PI). The primary outcome was a composite (COMP) of pre-eclampsia (PE) and/or small-for-gestational-age (SGA) neonate, and secondary outcomes were PE and SGA neonate individually. We assessed the ability of MRI-flow, MRI-PI and US-PI to distinguish between outcomes, and evaluated whether MRI-flow changed as gestation progressed.

RESULTS

Following 4D flow postprocessing and exclusions from the analysis, 74 women had 4D flow MRI data analyzed for both UtAs. Of these, 18 developed a COMP outcome: three developed PE only, 11 had a SGA neonate only and four had both. A comparison of the COMP group vs the no-COMP group found no differences in maternal age, body mass index, nulliparity, gravidity or race. For 66 of the 74 subjects, US data were also available. In these subjects, both median MRI-PI (0.95 vs 0.70; P < 0.01) and median US-PI (0.95 vs 0.73; P < 0.01) were significantly increased in subjects in the COMP group compared with those in the no-COMP group. The UtA blood-flow rate, as measured by MRI, did not increase significantly from the second to the third trimester (median flow (interquartile range (IQR)), 543 (419-698) vs 575 (440-746) mL/min; P = 0.77), but it was significantly lower overall in the COMP compared with the no-COMP group (median flow (IQR), 486 (366-598) vs 624 (457-749) mL/min; P = 0.04). The areas under the receiver-operating-characteristics curves for MRI-flow, MRI-PI and US-PI in predicting COMP were not significantly different (0.694, 0.737 and 0.731, respectively; P = 0.87).

CONCLUSIONS

4D flow MRI can yield physiological measures of UtA blood-flow rate and PI that are associated with adverse pregnancy outcome. This may open up new avenues in the future to expand the potential of this technique as a robust tool with which to evaluate UtA hemodynamics in pregnancy. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

A Coordinated Effort to Manage Soybean Rust in North America: A Success Story in Soybean Disease Monitoring

Existing crop monitoring programs determine the incidence and distribution of plant diseases and pathogens and assess the damage caused within a crop production region. These programs have traditionally used observed or predicted disease and pathogen data and environmental information to prescribe management practices that minimize crop loss. Monitoring programs are especially important for crops with broad geographic distribution or for diseases that can cause rapid and great economic losses. Successful monitoring programs have been developed for several plant diseases, including downy mildew of cucurbits, Fusarium head blight of wheat, potato late blight, and rusts of cereal crops. A recent example of a successful disease-monitoring program for an economically important crop is the soybean rust (SBR) monitoring effort within North America. SBR, caused by the fungus Phakopsora pachyrhizi, was first identified in the continental United States in November 2004. SBR causes moderate to severe yield losses globally. The fungus produces foliar lesions on soybean (Glycine max) and other legume hosts. P. pachyrhizi diverts nutrients from the host to its own growth and reproduction. The lesions also reduce photosynthetic area. Uredinia rupture the host epidermis and diminish stomatal regulation of transpiration to cause tissue desiccation and premature defoliation. Severe soybean yield losses can occur if plants defoliate during the mid-reproductive growth stages. The rapid response to the threat of SBR in North America resulted in an unprecedented amount of information dissemination and the development of a real-time, publicly available monitoring and prediction system known as the Soybean Rust-Pest Information Platform for Extension and Education (SBR-PIPE). The objectives of this article are (i) to highlight the successful response effort to SBR in North America, and (ii) to introduce researchers to the quantity and type of data generated by SBR-PIPE. Data from this system may now be used to answer questions about the biology, ecology, and epidemiology of an important pathogen and disease of soybean.

Preliminary activity in adrenocortical tumor (ACC) in phase I dose escalation study of intermittent oral dosing of OSI-906, a small-molecule insulin-like growth factor-1 receptor (IGF-1R) tyrosine kinase inhibitor in patients with advanced solid tumors

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Background: IGF-1R is overexpressed in various malignancies, and implicated in proliferation, survival, and metastasis. IGF-1R blockade increases apoptosis and reduces tumor growth in preclinical models. OSI-906 is an oral small molecule tyrosine kinase IGR-1R inhibitor. Methods: Patients (pt) with advanced solid tumours were enrolled to determine safety, tolerability, maximum tolerated dose, pharmacokinetics (PK), pharmacodynamics (PD) and preliminary anti-tumor activity. Results: 26 pt have been treated (14M:12F, median age 61 yrs) at 10, 20, 40, 80, 150, 300, and 450 mg on days (d) 1–3 q14 d. No dose-limiting toxicities have been observed to date. Drug-related toxicities include grade 1 fatigue, nausea, rash, diarrhea, tachycardia, proteinuria, pruritis and peripheral oedema. Linear PK was observed, with median terminal t1/2 3.5 hr; AUC0-∞ 25.8 μg.hr/mL; Cmax 3.20 μg/ml at 450mg. Plasma OSI-906 concentrations above the estimated efficacious concentration (1 μM) were attained at doses > 40mg. Glucose did not increase with rising OSI-906 concentration, but plasma insulin levels showed an upward trend, indicating potential PD effects. PD data on IGFR phosphorylation were analyzed. In total, 11 pt were treated for > 12 weeks (w). Of 3 pt with ACC, 1 pt had a partial response (43% reduction in primary and multiple lung metastases) and remains on treatment after 16 w, 1 pt was treated for 32 w, and 1 pt progressed after 4 w at 40mg. In addition, 1 pt with heavily pretreated NSCLC was treated for 43 w and 1 pt with progressive myxoid chondrosarcoma remains on treatment after 38 w. Conclusions: OSI 906 had minimal toxicity, dose proportional PK at dose levels up to 450mg tested d 1–3 q14 d, with preliminary antitumor activity seen, particularly in ACC. Dose escalation with 5 and 7 d schedules q14 d continues.

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Femoral neck stress fractures in military personnel--a case series

Femoral neck stress fractures (FNSF) are uncommon, representing 5% of all stress fractures. In military personnel, FNSF represents one of the more severe complications of training, which can result in medical discharge. Clinical examination findings are often non-specific and plain radiography may be inconclusive--leading to missed or late diagnosis of FNSF This paper highlights the significance of FNSFs in military personnel and alerts physicians to the potential diagnosis. We identified all military recruits, aged 17 to 26, who attended the Infantry Training Centre (Catterick, U.K.), over a four-year period from the 1st July 2002 to 30th June 2006, who had suffered a FNSF. The medical records, plain radiographs, bone scans and MRIs of the recruits were retrospectively reviewed. Of 250 stress fractures 20 were of the femoral neck; representing 8% of all stress fractures and an overall FNSF rate of 12 in 10,000 military recruits. FNSFs were most prevalent amongst Parachute Regiment recruits (1 in 250, p < 0.05). Onset of symptoms was most commonly between weeks 13-16 of training. The majority (17/20, 85%) of FNSFs were undisplaced, these were all treated conservatively. Three FNSFs were displaced on presentation and were treated surgically. Overall, the medical discharge rate was 40% (8/20). FNSFs are uncommon and the diagnosis remains a challenge to clinicians and requires a high index of suspicion in these young athletic individuals. In such individuals early referral for MRI is recommended, to aid prompt diagnosis and treatment and to prevent more serious sequelae.

Endoscopic evaluation of the esophagus in infants and children immediately following intraoperative use of transesophageal echocardiography

OBJECTIVE

Intraoperative transesophageal echocardiography (TEE) has evolved as an essential technique for use during pediatric cardiac surgery; however, few studies have evaluated the safety of TEE in children. This series reports endoscopic examination of the esophagus following intraoperative TEE in pediatric patients.

METHODS

Fifty children undergoing congenital heart surgery underwent flexible esophagoscopy that was performed after completion of their heart surgery and after the removal of the transesophageal echo probe. The patients' ages ranged from 4 days to 10 years old, and their weight ranged from 3.0 to 39.8 kg, with a mean weight of 12.6 kg.

RESULTS

Thirty-two of 50 patients (64%) had abnormal results shown on esophageal examinations; this occurred more frequently in the subset of patients weighing < 9 kg. No long-term feeding or swallowing difficulties were noted in any of the 48 patients who survived.

CONCLUSIONS

Intraoperative TEE in infants and children frequently caused mild mucosal injury. Care must be exercised in the insertion and manipulation of the probes.

Intraocular pressure-dependent light sensitivity in glaucoma

The intraocular pressure-dependent light sensitivity of discrete retinal points was measured using the Heijl-Krakau automated light-emitting diode perimeter with an appropriate software program. A total of 300 measurements of light sensitivity were recorded from six retinal points during the test period of 8-10 min; increased intraocular pressure was induced using a Langham scleral suction-cup system. The ocular pulsatile blood flow and the ophthalmic arterial pressure were measured in the same patients. The fluctuation of the light sensitivity was less than 5% over the test period in healthy eyes and remained unaffected by an intraocular-pressure increment of 20 mm Hg; a small decrease of sensitivity occurred at a pressure increment of 30 mm Hg. In glaucomatous eyes the light sensitivity was lower and the fluctuation of the light sensitivity at some but not all retinal points was substantially greater than in the controls. In the glaucomatous eyes, and intraocular-pressure increment of 20 mm Hg increased the fluctuation and decreased the light sensitivity. The pulsatile ocular blood flow was lower in the glaucomatous eyes but not severe enough to be solely responsible for the loss of vision. The coexistence of retinal points with normal and abnormal stabilities of light sensitivity in glaucomatous eyes was consistent with impaired blood flow in the lamina cribrosa.