Cerebrospinal fluid (CSF) fistulas are characterized by the egress of CSF from the intracranial cavity through an osteodural disruption between the subarachnoid space and a pneumatized structure within the skull base. Depending on the cause, CSF fistulas are classified as acquired or congenital, and acquired fistulas are further classified as traumatic, nontraumatic, or spontaneous. Spontaneous CSF fistulas are considered to result from a multifactorial process and have been postulated to represent a variant of idiopathic intracranial hypertension. However, an anatomic predisposition involving thinning of the cranial base, such as pneumatization of the sinus walls, must also be present. This process creates areas of structural weakness that act as potential pathways for CSF leaks, which most commonly occur in the ethmoid roof, sphenoid sinus, and temporal bone. Because CSF leaks may be overlooked, a result of their asymptomatic or subtle, intermittent course, a high level of suspicion is crucial in making an early diagnosis. However, CSF fistulas may be well seen at computed tomography (CT), which depicts bone defects, and magnetic resonance cisternography, which reveals the contents of herniated tissue. Knowledge of the location and size of the bone defect and herniated contents is crucial for the selection of surgical approach and grafting material.
Diagnosis of fetal ICH is amenable to antenatal US. Most of the cases identified are of high grade and usually detected during the third trimester. MRI is a valuable complementary tool in evaluating ICH. Conversely to that previously reported, postnatal survival is high but it entails the risk of adverse neurologic outcome in most neonates.
Objective To identify baseline characteristics of women with unexplained infertility to determine whether treatment with an aromatase inhibitor will result in a lower rate of multiple gestations than current standard ovulation induction medications. Design Randomized, prospective clinical trial Patients 900 couples with unexplained infertility Interventions: Ovarian stimulation with gonadotropins, clomiphene citrate, or letrozole in conjunction with intrauterine insemination. Setting Multicenter University based clinical practices. Main Outcome Measures Demographic, laboratory, imaging, and survey characteristics. Interventions Collection of baseline demographics, blood samples, and ultrasonographic assessments. Results Demographic characteristics of women receiving clomiphene citrate, letrozole, or gonadotropins for ovarian stimulation were very consistent. Their mean age was 32.2 ± 4.4 years and infertility duration was 34.7± 25.7 months, with 59% primary infertility. More than 1/3 of the women were current or past smokers. The mean BMI was 27 and mean AMH level was 2.6; only 11 women (1.3%) had antral follicle counts of less than 5. Similar observations were identified for hormonal profiles, ultrasound characterization of the ovaries, semen parameters, and quality of life assessments in both male and female partners. Conclusion The cause of infertility in the couples recruited to this treatment trial is elusive, as the women were regularly ovulating and had evidence of good ovarian reserve both by basal FSH, AMH levels, and antral follicle counts; the male partners had normal semen parameters. The three treatment subgroups have common baseline characteristics, thereby providing comparable patient populations for testing the hypothesis that use of letrozole for ovarian stimulation can reduce the rates of multiples from that observed with gonadotropin and clomiphene citrate treatment.
In recent years, with the development of ultrafast sequences, magnetic resonance (MR) imaging has been established as a valuable diagnostic modality complementary to ultrasonography (US). MR imaging offers several technical advantages over US, including a larger field of view, fewer limitations due to maternal habitus, and the ability to visualize fetal anatomy regardless of fetal presentation. The authors discuss the most frequently found thoracic abnormalities, including congenital diaphragmatic hernia, congenital cystic adenomatoid malformation, bronchopulmonary sequestration, bronchogenic cyst, congenital high airway obstruction syndrome, and bronchial obstruction by a mucus plug, specifically with respect to the effect of fetal MR imaging on diagnosis and treatment. MR imaging can assist in establishing the prognosis and in perinatal management, especially in the case of congenital diaphragmatic hernia, which is the most common indication for thoracic MR imaging. MR imaging can demonstrate hernial contents and quantify lung volume better than US, allowing the prognosis to be determined and postpartum extracorporeal membrane oxygenation needs to be estimated. MR imaging can also be used to distinguish different types of cystic adenomatoid malformations, identify the anomalous vessels of pulmonary sequestration, and assess the functional effects of bronchogenic cysts. Balanced sequences (steady-state free precession sequences) allow performance of unenhanced thoracic vascular studies, which are useful in the diagnosis of intralobar or extralobar sequestration. In summary, fetal MR imaging can provide additional data useful in establishing prognosis and in perinatal management of thoracic malformations.
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