Gihad E. Chalouhi

Fetoplacental Oxygenation in an Intrauterine Growth Restriction Rat Model by Using Blood Oxygen Level–Dependent MR Imaging at 4.7 T

PURPOSEnTo investigate blood oxygen level-dependent (BOLD) magnetic resonance (MR) imaging in an intrauterine growth restriction (IUGR) rat model as a noninvasive in vivo tool to evaluate the response of the fetoplacental units (FPUs) to oxygenationnnnMATERIALS AND METHODSnAll procedures were approved by the animal care committee. The study was performed between February and July 2010. The IUGR model based on the ligation of the left uterine vascular pedicle at embryonic day 17 of gestation was validated by weighing placentas and fetuses after MR imaging. FPUs in the left and right uterine horns were IUGR cases and controls, respectively. A small-animal 4.7-T MR imager was used. Multiple gradient-echo sequence (repetition time msec/echo time msec, 800/1.8-49.8) was performed at embryonic day 19. T2* relaxation time was measured before and after maternal hyperoxygenation for live FPUs in placenta, fetal liver, and brain. The effect of hyperoxygenation on BOLD MR imaging was analyzed with change in T2* between hyperoxygenation and ambient air. After dissection, live fetuses from both horns were identified and weighed. Changes in T2* were compared based on Student t tests. A mixed model was used to compare BOLD effect among horns and organs.nnnRESULTSnSixteen rats were studied. There was a significant fetal weight decrease in the IUGR FPUs (-21.9%; P < .001). Change in T2* differed significantly between IUGR cases and controls for placenta (5.25 msec vs 11.25 msec; P < .001) and fetal brain (3.7 msec vs 7.17 msec; P = .02), whereas there was no significant difference in the fetal liver (2.72 msec vs 3.18 msec; P = .47).nnnCONCLUSIONnBOLD MR imaging at 4.7 T can be used to evaluate the response to oxygenation in normal and IUGR FPUs. This technique has a potential role in the assessment of human pregnancy.

Use of intravoxel incoherent motion MR imaging to assess placental perfusion in a murine model of placental insufficiency.

ObjectivesThe objectives of this study were to evaluate the potential of intravoxel incoherent motion (IVIM) magnetic resonance imaging at 4.7 T to distinguish decreased placental perfusion from normal perfusion in a controlled murine model and to determine the effect of transient maternal hyperoxygenation on placental microvascularization. Materials and MethodsThe study was approved by our animal care committee. Ten pregnant rats underwent ligation of the left uterine vascular pedicle on the 17th embryonic day (E17). A multishot diffusion-weighted spin-echo echo-planar imaging sequence, using 14 b values (b10 to b800), was performed on the 19th embryonic day (E19) under room air and during maternal hyperoxygenation. For each placenta and its 2 layers, the signal intensity decay curve according to the b values was obtained. The following IVIM parameters were calculated using biexponential fitting: the diffusion coefficient (D), the pseudodiffusion coefficient (D*), and the perfusion fraction (f). Mixed regression modeling was used to analyze the effect of ligation status, oxygenation, and the placental layer on IVIM parameters. ResultsSeventy-three placentas were examined: 23 in the ligated horn and 50 in the nonligated control horn. The IVIM parameters were obtained for 67% of the placentas. In the control horn, the mean (SD) values on room air were 28% (13%), 9.6 (9) ×10−3 mm2/s, and 0.88 (0.36) ×10−3 mm2/s for the perfusion fraction, the pseudodiffusion coefficient, and the diffusion coefficient, respectively. The perfusion fraction was significantly decreased in the ligated horn (−6.7% [1.9%]; P = 0.001) and during maternal hyperoxygenation (−3.3 [1.64%]; P = 0.047). The diffusion coefficient increased significantly during the hyperoxygenation (0.26 [0.04] × 10−3 mm2/s; P = 0.0001) and in the inner placental layer (0.21 [0.05] ×10−3 mm2/s; P = 0.0001). ConclusionsThe perfusion fraction is a sensitive marker of decreased placental perfusion. The perfusion fraction and the diffusion coefficient are modified during the hyperoxygenation. Our IVIM-based approach may help in the investigation and early diagnosis of vascular diseases during pregnancy.

Measurement of placental perfusion by dynamic contrast-enhanced MRI at 4.7 T.

Purpose:The purposes of this study were to develop quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) at 4.7 T for perfusion measurement and to evaluate the ability of this technique to distinguish between low and normal levels of placental perfusion in a controlled rat model. Materials and Methods:This study was approved by the animal care committee. Poor placental perfusion in the left uterine horn was achieved by ligation of the left uterine vascular pedicle on the 17th embryonic day in 12 pregnant rats. High–temporal resolution DCE-MRI (<1 second) was performed on the 19th embryonic day. Single-compartment analysis was used to calculate placental blood flow (F), volume fraction (Vb), and time delay (Dt) for each placenta and its 2 layers in both uterine horns. Mixed regression analysis was used to compare parameters between the ligated and nonligated horn and between placental layers. Results:We examined 53 placentas: 11 on the ligated side and 42 on the control side. On the control side, the mean (SD) values were 115 (72) mL/min per 100 mL for F, 38.6% (11.7%) for Vb, and 5.5 (5.3) seconds for Dt.Placental blood flow was significantly lower on the ligated side (66 [30] mL/min per 100 mL; P = 0.001).Placental blood flow and Vb were significantly higher, whereas Dt was significantly lower in the inner layer than in the outer layer in both horns (P=0.0001). Conclusions:Quantitative analyses of perfusion are feasible with DCE-MRI at 4.7 T.Dynamic contrast-enhanced magnetic resonance imaging can differentiate between low and normal levels of placental perfusion in a rat model. Dynamic contrast-enhanced magnetic resonance imaging at 4.7 T is a promising preclinical tool for quantifying and monitoring microvascularization.

Laparoscopic uterovaginal anastomosis in Mayer-Rokitansky-Küster-Hauser syndrome with functioning horn

OBJECTIVEnTo reestablish uterovaginal continuity using a total laparoscopic procedure in Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome with a functioning right horn.nnnDESIGNnCase report.nnnSETTINGnUniversity hospital of Hotel Dieu de Lyon.nnnPATIENT(S)nA 13-year-old woman with cyclic abdominal pain. We diagnosed MRKH syndrome with cyclic pain due to a hematometra in a functioning right horn associated to a right hematosalpinx and a nonfunctioning left horn.nnnINTERVENTION(S)nReestablishing uterovaginal continuity with excision of the left rudimentary horn via a total laparoscopic procedure.nnnMAIN OUTCOME MEASURE(S)nRestoring regular menstruation.nnnRESULT(S)nAfter total laparoscopic uterovaginal anastomosis and excision of the left nonfunctioning horn, the patients menstruation resumed 3 months later, and regular, unimpeded menstrual flow was still present at the 2-year-follow-up evaluation.nnnCONCLUSION(S)nTotal laparoscopic reestablishment of uterovaginal continuity in MRKH syndrome with a functioning horn is a valuable alternative to the currently recommended treatment (laparotomy and radical excision of the rudimentary uterus).

Formative Assessment Based on an Audit and Feedback Improves Nuchal Translucency Ultrasound Image Quality

The purpose of this work was to study the impact of an audit and feedback on the quality of routine first‐trimester nuchal transparency ultrasound images.

Randomized Clinical Trial of Virtual Reality Simulation Training for Transvaginal Gynecologic Ultrasound Skills.

To compare the impact of virtual reality simulation training and theoretical teaching on the ability of inexperienced trainees to produce adequate virtual transvaginal ultrasound images.

Segregation of mitochondrial DNA mutations in the human placenta: implication for prenatal diagnosis of mtDNA disorders

Background Mitochondrial DNA (mtDNA) disorders have a high clinical variability, mainly explained by variation of the mutant load across tissues. The high recurrence risk of these serious diseases commonly results in requests from at-risk couples for prenatal diagnosis (PND), based on determination of the mutant load on a chorionic villous sample (CVS). Such procedures are hampered by the lack of data regarding mtDNA segregation in the placenta. The objectives of this report were to determine whether mutant loads (1) are homogeneously distributed across the whole placentas, (2) correlate with those in amniocytes and cord blood cells and (3) correlate with the mtDNA copy number. Methods We collected 11 whole placentas carrying various mtDNA mutations (m.3243A>G, m.8344A>G, m.8993T>G, m.9185T>C and m.10197G>A) and, when possible, corresponding amniotic fluid samples (AFSs) and cord blood samples. We measured mutant loads in multiple samples from each placenta (n= 6–37), amniocytes and cord blood cells, as well as total mtDNA content in placenta samples. Results Load distribution was homogeneous at the sample level when average mutant load was low (<20%) or high (>80%) at the whole placenta level. By contrast, a marked heterogeneity was observed (up to 43%) in the intermediate range (20%–80%), the closer it was to 40%–50% the mutant load, the wider the distribution. Mutant loads were found to be similar in amniocytes and cord blood cells, at variance with placenta samples. mtDNA content correlated to mutant load in m.3243A>G placentas only. Conclusion These data indicate that (1) mutant load determined from CVS has to be interpreted with caution for PND of some mtDNA disorders and should be associated with/substituted by a mutant load measurement on amniocytes; (2) the m.3243A>G mutation behaves differently from other mtDNA mutations with respect to the impact on mtDNA copy number, as previously shown in human preimplantation embryogenesis.

Prenatal incision of ureterocele causing bladder outlet obstruction: a multicenter case series

We reviewed data from a cohort of fetuses with ureterocele diagnosed and operated prenatally in four fetal therapy centers. Inclusion criteria were (1) ureterocele confirmed on detailed fetal ultrasound examination, (2) absence of additional fetal malformations, and (3) fetal intervention to decompress the ureterocele with local institutional review boards approval. Data on sonographic follow‐up, obstetrical, neonatal outcome, and postnatal evaluation were collected. Ten cases of prenatally treated ureterocele are described. Six cases benefited from a fetoscopy for laser incision and decompression, two cases had an ultrasound guided puncture before resorting to a fetoscopy with laser incision, one case had a balloon catheterization under ultrasound guidance, and one case had an ultrasound‐guided opening of the ureterocele with a laser fiber passed through a 20‐gauge needle. Mean gestational age at diagnosis was 21.6 GW. Two cases underwent termination of pregnancy. The remaining eight cases recovered normal amniotic fluid volume and delivered a liveborn child at a mean gestational age of 38.6 GW with normal creatinine levels during the first week of life. Prenatal incision provided complete treatment of severely obstructive ureteroceles in 80% of the cases and allowed improvement of urinary electrolytes, renal size and echogenicity, bladder filling in all survivors, and recollection of normal amniotic fluid volume, in case of oligoanhydramnios.

Twin-to-Twin Transfusion Syndrome: From Observational Evidence to Randomized Controlled Trials.

Fetoscopic surgery is widely accepted as the preferred first-line treatment for twin-twin transfusion syndrome (TTTS). Nonetheless, the broad diffusion of this technique relies on a single multicentric-randomized trial. We hereby question this trial in a post-hoc Bayesian analysis, submitting its results to several scenarios comprising the alternative published non-randomized literature and pessimistic opinions regarding this surgery. Furthermore, we also discuss further refinements in indications, questioning potential alternatives in early stages of the disease.