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.

Modified frailty index predicts early outcomes after colorectal surgery: an ACS-NSQIP study

AIM

Frailty is defined as a decrease in physiological reserve with increased risk of morbidity following significant physiological stressors. This study examines the predictive power of the five-item modified frailty index (5-mFI) in predicting outcomes in colorectal surgery patients.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program Database was queried from 2011 to 2016 to determine the predictive power of 5-mFI in patients who had colorectal surgery.

RESULTS

Of 295 490 patients, 45.8% had a score of 0, 36.2% had a score of 1 and 18% had a score of ≥ 2. On univariate analysis, frailer patients had significantly greater incidences for overall morbidity, serious morbidity, mortality, prolonged length of hospital stay, discharge to a facility other than home, reoperation and unplanned readmission. These findings were consistent on multivariate analysis where the frailest patients had greater odds of postoperative overall morbidity (OR 1.39; 95% CI 1.35-1.43), serious morbidity (OR 1.39; 95% CI 1.33-1.45), mortality (OR 2.00; 95% CI 1.87-2.14), prolonged length of hospital stay (OR 1.24; 95% CI 1.20-1.27), discharge destination to a facility other than home (OR 2.80; 95% CI 2.70-2.90), reoperation (OR 1.17; 95% CI 1.11-1.23) and unplanned readmission (OR 1.31; 95% CI 1.26-1.36). Weighted kappa statistics showed strong agreement between the 5-mFI and 11-mFI (kappa = 0.987, P < 0.001).

CONCLUSIONS

The 5-mFI is a valid and easy to use predictor of 30-day postoperative outcomes after colorectal surgery. This tool may guide the surgeon to proactively recognize frail patients to instigate interventions to optimize them preoperatively.

Visual evoked potential & brainstem auditory evoked potentials in acute attack & after the attack of migraine

PURPOSE

To study the effect on visual evoked potential (VEP) and brainstem auditory evoked potential (BAEP) at time of acute attack and after 7 days of the attack of migraine.

MATERIAL AND METHODS

We studied BAEP and pattern reversal VEP in 25 patients during acute attack and after 7 days of the attack. The diagnosis of migraine was established according to criteria given by international headache society (IHS). Peak and interpeak latencies (IPL's) of BAEP and P100 latency of VEP were the main criteria to judge abnormalities.

RESULTS

There were prolonged peak and interpeak latencies in BAEP and prolonged peak latency (P100) in VEP at the time of acute attack of migraine. The data of these abnormal recording were highly significant. After 7 days when the attack was over, we recorded the BAEP and VEP again. The observation obtained at this time was comparable to normal values.

CONCLUSIONS

From the observation of this study we can safely conclude that in acute attacks of migraine there may be some pathological changes in different areas of brain and brainstem, producing changes in evoked potential which are statistically highly significant. However, these changes are reversible, as the values of BAEP & VEP on 7th day after the attack were comparable to those observed in normal healthy control.