Imaging of Female Pelvic Emergencies.

Pelvic pain is a common complaint in female patients who present to the emergency department. Although encountered frequently, the path to a definitive diagnosis is not always a straightforward one, and imaging offers a valuable tool to aid in this diagnostic challenge. Radiologists must be familiar with the most common etiologies of female pelvic pain in the emergency setting, their imaging characteristics, and the best way to further evaluate challenging clinical presentations. This allows the radiologist to serve as a valuable asset to the treating physician, aiding in accurate diagnosis, and in guiding the course of treatment, all while ensuring the "Image Wisely" principle. A sonographic approach to female patients presenting to the emergency setting with pelvic pain has been presented in this article and some example entities along with their imaging findings have also been reviewed.

Variability in myocardial metabolism on serial tumor (18)F-FDG PET/CT scans.

(18)F Fluorodeoxyglucose (FDG) positron emission tomography (PET) scans are performed routinely for oncologic patients. Myocardial uptake can vary among patients and between serial studies in the same patient. Our study aims to evaluate myocardial metabolism on staging FDG PET scans and to analyze factors influencing patterns of cardiac uptake, and their relevance. We analyzed retrospectively 100 PET-CT scans from 20 fasting lymphoma patients. Distribution of myocardial uptake was determined by visual assessment and the maximum standardized uptake value (SUVm) was calculated. Multiple variables were analyzed including: fasting length, cardiovascular risk factors, SUVm, and location of uptake. We found no correlation between fasting hours and cardiac uptake (p-value: 0.4786). There was a trend that showed less uptake in patients scanned in the afternoon versus the morning, although this was not statistically significant. The location of maximum uptake was unexpectedly variable in several patients and could not be ascertained to a specific cause. Interestingly, we found no correlation between cardiac risk factors and the amount of myocardial uptake. Myocardial FDG uptake is spatially and temporally heterogeneous. Differences in myocardial wall pattern and peak uptake exist and may not be explained by the length of fasting, gender, age or cardiac risk factors. This variability may occur in daily cardiac evaluations and affect interpretations of sarcoidosis and viability studies and should be further explored. A larger cohort study is necessary to confirm that our findings do not confer a higher cardiac risk profile to the cancer patient.

¹¹¹In-DTPA cisternography with SPECT/CT for the evaluation of normal pressure hydrocephalus.

Although new MR imaging techniques can provide high-resolution information on CSF dynamics and are not associated with ionizing radiation, SPECT/CT cisternography is a valuable alternative for those with contraindications to MR imaging. SPECT/CT cisternography combines functional and anatomic imaging to provide accurate and detailed information on CSF distribution to be used in conjunction with clinical findings for the diagnosis and evaluation of NPH, as illustrated in this case report.

A mechanism for functional segregation of mitochondrial and cytosolic genetic codes.

The coexistence of multiple gene translation machineries is a feature of eukaryotic cells and a result of the endosymbiotic events that gave rise to mitochondria, plastids, and other organelles. The conditions required for the integration of these apparatuses within a single cell are not understood, but current evidence indicates that complete ablation of the mitochondrial protein synthesis apparatus and its substitution by its cytosolic equivalent is not possible. Why certain mitochondrial components and not others can be substituted by cytosolic equivalents is not known. In trypanosomatids this situation reaches a limit, because certain aminoacyl-tRNA synthetases are mitochondrial specific despite the fact that all tRNAs in these organisms are shared between cytosol and mitochondria. Here we report that a mitochondria-specific lysyl-tRNA synthetase in Trypanosoma has evolved a mechanism to block the activity of the enzyme during its synthesis and translocation. Only when the enzyme reaches the mitochondria is it activated through the cleavage of a C-terminal structural extension, preventing the possibility of the enzyme being active in the cytosol.