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.

The objective of our study was to determine the utility of diffusion-weighted magnetic resonance (DWMR) to differentiate the atypical uterine leiomyomas and sarcomas, establishing a cut-off value of the apparent diffusion coefficient (ADC) to rule out the malignancy. We performed a diagnostic accuracy retrospective study including 10 patients with pelvic sarcomas and 17 patients with leiomyomas. Atypical morphological features in magnetic resonance (MR) studies occurred in 58.8% of the patients, leading to a significant number of indeterminate diagnoses. In contrast, ADC values were consistent for leiomyomas, sarcomas, primary tumours, recurrences, intrauterine and in the extrauterine pelvic locations. The ADC cut-off value was set in 1 (×10 mm/s). Thus, the ADC values equal or superior to 1 × 10 mm/s were always associated with a leiomyoma. The structural MR accuracy was 66.7%, reaching 100% when using DWMR with dichotomised ADC values. Diffusion-weighted imaging with the quantitative measurement of ADC may be considered a useful preoperative test for the differentiation of atypical leiomyomas from sarcomas. Impact statement What is already known on this subject? Papers reporting the utility of a diffusion-weighted MR for the diagnosis of uterine sarcomas are scarce and consist of a small series. However, the published results are consistent with our study, with the decreased ADCs in the case of malignancy. What do the results of this study add? The main differential characteristic of our study is that we selected only the atypical leiomyomas: they share sonographic and MR features with sarcomas, which often leads to an inaccurate diagnosis. This is also the first paper reporting on the role of DWMR with ADC for these types of tumours in extrauterine pelvic locations. We demonstrated a consistent relationship between dichotomised ADC values in leiomyomas/sarcomas for these particular cases and in recurrent tumours, with no overlap between both the groups, as a difference with the previous reports. What are the implications of these findings for clinical practice and/or further research? Our study can be considered as a proof of concept supporting DWMR with ADC measurement as a useful tool to enhance the diagnostic accuracy of MR, highlighting its value to rule out malignancy. Hence, DWMR seems to be a potential useful test to include in the preoperative evaluation of clinically atypical uterine tumours.

We found gene expression patterns indicative of inflammation in human placentas after suspected preterm labour regardless of whether the deliveries occurred preterm or at term. Similarly, a trend towards altered expression of angiogeneic factors was not limited to preterm birth. These findings suggest that the biological mechanisms underlying threatened preterm labour affect pregnancies independently of gestational age at birth.

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