Incidental findings involving the temporomandibular joint on computed tomography and magnetic resonance imaging.

The temporomandibular joint (TMJ) is frequently imaged in head and neck computed tomography (CT) and magnetic resonance imaging (MRI) studies. Depending on the indication for the study, an abnormality of the TMJ may be an incidental finding. These findings encompass both intra- and extra-articular disorders. They may also be related to local, regional or systemic conditions. Familiarity with these findings along with pertinent clinical information helps narrow the list of differential diagnoses. While definitive diagnosis may not be immediately apparent, a systematic approach contributes to improved discussions between clinicians and radiologists and better patient management.

Polycomb group genes are required for neuronal pruning in Drosophila.

BACKGROUND: Pruning that selectively eliminates unnecessary or incorrect neurites is required for proper wiring of the mature nervous system. During Drosophila metamorphosis, dendritic arbourization sensory neurons (ddaCs) and mushroom body (MB) γ neurons can selectively prune their larval dendrites and/or axons in response to the steroid hormone ecdysone. An ecdysone-induced transcriptional cascade plays a key role in initiating neuronal pruning. However, how downstream components of ecdysone signalling are induced remains not entirely understood. RESULTS: Here, we identify that Scm, a component of Polycomb group (PcG) complexes, is required for dendrite pruning of ddaC neurons. We show that two PcG complexes, PRC1 and PRC2, are important for dendrite pruning. Interestingly, depletion of PRC1 strongly enhances ectopic expression of Abdominal B (Abd-B) and Sex combs reduced, whereas loss of PRC2 causes mild upregulation of Ultrabithorax and Abdominal A in ddaC neurons. Among these Hox genes, overexpression of Abd-B causes the most severe pruning defects, suggesting its dominant effect. Knockdown of the core PRC1 component Polyhomeotic (Ph) or Abd-B overexpression selectively downregulates Mical expression, thereby inhibiting ecdysone signalling. Finally, Ph is also required for axon pruning and Abd-B silencing in MB γ neurons, indicating a conserved function of PRC1 in two types of pruning. CONCLUSIONS: This study demonstrates important roles of PcG and Hox genes in regulating ecdysone signalling and neuronal pruning in Drosophila. Moreover, our findings suggest a non-canonical and PRC2-independent role of PRC1 in Hox gene silencing during neuronal pruning.

Drosophila GSK3ß promotes microtubule disassembly and dendrite pruning in sensory neurons.

The evolutionarily conserved Glycogen Synthase Kinase 3ß (GSK3ß), a negative regulator of microtubules, is crucial for neuronal polarization, growth and migration during animal development. However, it remains unknown whether GSK3ß regulates neuronal pruning, which is a regressive process. Here, we report that the Drosophila GSK3ß homologue Shaggy (Sgg) is cell-autonomously required for dendrite pruning of ddaC sensory neurons during metamorphosis. Sgg is necessary and sufficient to promote microtubule depolymerization, turnover and disassembly in the dendrites. Although Sgg is not required for the minus-end-out microtubule orientation in dendrites, hyperactivated Sgg can disturb the dendritic microtubule orientation. Moreover, our pharmacological and genetic data suggest that Sgg is required to promote dendrite pruning at least partly via microtubule disassembly. We show that Sgg and Par-1 kinases act synergistically to promote microtubule disassembly and dendrite pruning. Thus, Sgg and Par-1 might converge on and phosphorylate a common downstream microtubule-associated protein(s) to disassemble microtubules and thereby facilitate dendrite pruning.

Drosophila CLASP regulates microtubule orientation and dendrite pruning by suppressing Par-1 kinase.

The evolutionarily conserved CLASPs (cytoplasmic linker-associated proteins) are microtubule-associated proteins that inhibit microtubule catastrophe and promote rescue. CLASPs can regulate axonal elongation and dendrite branching in growing neurons. However, their roles in microtubule orientation and neurite pruning in remodeling neurons remain unknown. Here, we identify the Drosophila CLASP homolog Orbit/MAST, which is required for dendrite pruning in ddaC sensory neurons during metamorphosis. Orbit is important for maintenance of the minus-end-out microtubule orientation in ddaC dendrites. Our structural analysis reveals that the microtubule lattice-binding TOG2 domain is required for Orbit to regulate dendritic microtubule orientation and dendrite pruning. In a genetic modifier screen, we further identify the conserved Par-1 kinase as a suppressor of Orbit in dendritic microtubule orientation. Moreover, elevated Par-1 function impairs dendritic microtubule orientation and dendrite pruning, phenocopying orbit mutants. Overall, our study demonstrates that Drosophila CLASP governs dendritic microtubule orientation and dendrite pruning at least partly via suppressing Par-1 kinase.

Deep Learning Model for Automated Detection and Classification of Central Canal, Lateral Recess, and Neural Foraminal Stenosis at Lumbar Spine MRI.

Background Assessment of lumbar spinal stenosis at MRI is repetitive and time consuming. Deep learning (DL) could improve -productivity and the consistency of reporting. Purpose To develop a DL model for automated detection and classification of lumbar central canal, lateral recess, and neural -foraminal stenosis. Materials and Methods In this retrospective study, lumbar spine MRI scans obtained from September 2015 to September 2018 were included. Studies of patients with spinal instrumentation or studies with suboptimal image quality, as well as postgadolinium studies and studies of patients with scoliosis, were excluded. Axial T2-weighted and sagittal T1-weighted images were used. Studies were split into an internal training set (80%), validation set (9%), and test set (11%). Training data were labeled by four radiologists using predefined gradings (normal, mild, moderate, and severe). A two-component DL model was developed. First, a convolutional neural network (CNN) was trained to detect the region of interest (ROI), with a second CNN for classification. An internal test set was labeled by a musculoskeletal radiologist with 31 years of experience (reference standard) and two subspecialist radiologists (radiologist 1: A.M., 5 years of experience; radiologist 2: J.T.P.D.H., 9 years of experience). DL model performance on an external test set was evaluated. Detection recall (in percentage), interrater agreement (Gwet κ), sensitivity, and specificity were calculated. Results Overall, 446 MRI lumbar spine studies were analyzed (446 patients; mean age ± standard deviation, 52 years ± 19; 240 women), with 396 patients in the training (80%) and validation (9%) sets and 50 (11%) in the internal test set. For internal testing, DL model and radiologist central canal recall were greater than 99%, with reduced neural foramina recall for the DL model (84.5%) and radiologist 1 (83.9%) compared with radiologist 2 (97.1%) (P < .001). For internal testing, dichotomous classification (normal or mild vs moderate or severe) showed almost-perfect agreement for both radiologists and the DL model, with respective κ values of 0.98, 0.98, and 0.96 for the central canal; 0.92, 0.95, and 0.92 for lateral recesses; and 0.94, 0.95, and 0.89 for neural foramina (P < .001). External testing with 100 MRI scans of lumbar spines showed almost perfect agreement for the DL model for dichotomous classification of all ROIs (κ, 0.95-0.96; P < .001). Conclusion A deep learning model showed comparable agreement with subspecialist radiologists for detection and classification of central canal and lateral recess stenosis, with slightly lower agreement for neural foraminal stenosis at lumbar spine MRI. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Hayashi in this issue.

Living Longer, With or Without Disability? A Global and Longitudinal Perspective.

BACKGROUND: Significant gains in life expectancy have been achieved, but living longer does not necessarily mean the years gained are productive and healthy. Different theories predict different patterns of time trends in old-age disability prevalence. METHODS: Using the Gateway to Global Aging Data, which provides internationally harmonized longitudinal data from the Health and Retirement Study and its sister surveys, we compare time trends (from 2004 to 2014) in disability prevalence across countries. RESULTS: Disability prevalence varies greatly across countries, and divergent time trends are observed across countries. For countries such as Belgium, Czechia, and Mexico, we observe an increase of disability prevalence, whereas in countries such as Denmark, England, Greece, Korea, Poland, and Sweden, we observe a substantial decrease in disability prevalence. Looking further into the severity of disability, we often observe differential trends in prevalence, but there is no evidence supporting the dynamic equilibrium hypothesis that predicts increased prevalence of modest disability but a decrease in severe disability prevalence. CONCLUSIONS: Significant gains in life expectancy have translated into different gains in healthy years of life across different countries. Diverse time trends in disability prevalence across countries reaffirm that the expansion of late-life disability is not inevitable.

Shock in the first 24 h of intensive care unit stay: observational study of protocol-based fluid management.

Precision in fluid management for shock could lead to better clinical outcomes. We evaluated the association of protocol-based fluid management with intensive care unit (ICU) and hospital mortality. We performed an observational study of mechanically ventilated patients admitted directly from our emergency department to the ICU from August 2011 to December 2013, who had circulatory shock in the first 24 h of ICU stay (systolic blood pressure <90 mmHg at ICU admission or lactate >4 mmol/L). Patients with onset of shock beyond 24 h of ICU stay were excluded. Protocol-based fluid management required close physician-nurse cooperation and computerized documentation, checking for fluid response (≥10% arterial pulse pressure or stroke volume increase after two consecutive 250-mL crystalloid boluses), and fluid loading with repeated 500-mL boluses until fluid response became negative. Six hundred twelve mechanically ventilated patients with shock (mean [±SD] age, 63.0 years [16.5]; 252 or 41.2% females; mean Acute Physiology and Chronic Health Evaluation II score, 30.2 [8.8]) were studied. The fluid management protocol was used 455 times for 242 patients (39.5% of 612 patients) within the first 24 h of ICU stay, with 244 (53.6% of 455) positive responses. Adjusted for age, sex, Acute Physiology and Chronic Health Evaluation II score, comorbidity, and admission year, protocol use was associated with reduced ICU mortality (odds ratio, 0.60; 95% confidence interval, 0.39-0.94; P = 0.025) but not hospital mortality (odds ratio, 0.82; 95% confidence interval, 0.54-1.23; P = 0.369). Among mechanically ventilated patients with shock within the first 24 h of ICU stay, about half had positive fluid responses. Adherence to protocol-based fluid management was associated with improved ICU survival.

Planned conservative management of placenta accreta - experience of a regional general hospital.

OBJECTIVE: There are only a few series treating ≥10 cases of accreta conservatively, all from university teaching hospitals, with reported success rate of 60-85%. We reported the first series of accreta managed by planned uterine conservation in the setting of non-university district general hospital. METHODS: Women with placenta previa overlying previous cesarean scar who desired uterine conservation were included. For cases with accreta confirmed during cesarean delivery, placenta was purposefully left behind, followed immediately by uterine artery embolization. Cases were followed in our special postnatal clinic. Charts were reviewed to retrieve clinical details. RESULTS: Among 15 cases of placenta previa overlying cesarean scar opting for conservative management, 12 (80%) were confirmed to be accreta intra-operatively. They had 20-100% of the adherent placentae retained (median 90%) and their uterus preserved. Postpartum, abnormal vaginal bleeding and/or infection led to unscheduled readmission in 67% (8/12), all managed conservatively. Sonographic resolution of placenta took 2-13 months (median 6.6), and was later than menstrual return in 11 cases. CONCLUSIONS: Successful planned conservative management of placenta accreta is feasible in the setting of district general hospital with facilities for interventional radiology.

Entrapment of metal clusters in metal-organic framework channels by extended hooks anchored at open metal sites.

Reported here are the new concept of utilizing open metal sites (OMSs) for architectural pore design and its practical implementation. Specifically, it is shown here that OMSs can be used to run extended hooks (isonicotinates in this work) from the framework walls to the channel centers to effect the capture of single metal ions or clusters, with the concurrent partitioning of the large channel spaces into multiple domains, alteration of the host-guest charge relationship and associated guest-exchange properties, and transfer of OMSs from the walls to the channel centers. The concept of the extended hook, demonstrated here in the multicomponent dual-metal and dual-ligand system, should be generally applicable to a range of framework types.

Use of second-line therapies for management of massive primary postpartum hemorrhage.

OBJECTIVE: To determine rates of use and success of second-line therapies for massive primary postpartum hemorrhage (PPH). METHODS: A retrospective cohort study was conducted among 91 women who gave birth at Kwong Wah Hospital, Hong Kong, between January 1, 2006, and December 31, 2011. Inclusion criteria were gestational age of at least 24 weeks and massive PPH (defined as blood loss ≥1500 mL within 24 hours after birth). Second-line therapies assessed were uterine compression sutures, uterine artery embolization, and balloon tamponade after failure of uterine massage and uterotonic agents to stop bleeding. RESULTS: The rate of massive PPH was 2.65 per 1000 births. Second-line therapies were used among 42 women with PPH, equivalent to a rate of 1.23 per 1000 births. Only 21.4% of the women who received second-line therapies required rescue hysterectomy. A rising trend was observed for the use of second-line therapies, whereas the incidence of rescue hysterectomy and estimated blood loss were found to concomitantly decrease. CONCLUSION: Increasing use of second-line therapies among women with massive PPH was associated with a decreasing trend for rescue hysterectomy. Obstetricians should, therefore, consider all available interventions to stop PPH, including early use of second-line options.

Intracranial aneurysms: midterm outcome of pipeline embolization device--a prospective study in 143 patients with 178 aneurysms.

PURPOSE: To evaluate the midterm clinical and angiographic outcomes after pipeline embolization device (PED) placement for treatment of intracranial aneurysms. MATERIALS AND METHODS: This prospective nonrandomized multicenter study was approved by the review boards of all involved centers; informed consent was obtained. Patients (143 patients, 178 aneurysms) with unruptured saccular or fusiform aneurysms or recurrent aneurysms after previous treatment were included and observed angiographically for up to 18 months and clinically for up to 3 years. Study endpoints included complete aneurysm occlusion; neurologic complications within 30 days and up to 3 years; clinical outcome of cranial nerve palsy after PED placement; angiographic evidence of occlusion or stenosis of parent artery and that of occlusion of covered side branches at 6, 12, and 18 months; and clinical and computed tomographic evidence of perforator infarction. RESULTS: There were five (3.5%) cases of periprocedural death or major stroke (modified Rankin Scale [mRS] > 3) (95% confidence interval [CI]: 1.3%, 8.4%), including two posttreatment delayed ruptures, two intracerebral hemorrhages, and one thromboembolism. Five (3.5%) patients had minor neurologic complications within 30 days (mRS = 1) (95% CI: 1.3%, 8.4%), including transient ischemic attack (n = 2), small cerebral infarction (n = 2), and cranial nerve palsy (n = 1). Beyond 30 days, there was one fatal intracerebral hemorrhage and one transient ischemic attack. Ten of 13 patients (95% CI: 46%, 93.8%) completely recovered from symptoms of cranial nerve palsy within a median of 3.5 months. Angiographic results at 18 months revealed a complete aneurysm occlusion rate of 84% (49 of 58; 95% CI: 72.1%, 92.2%), with no cases of parent artery occlusion, parent artery stenosis (<50%) in three patients, and occlusion of a covered side branch in two cases (posterior communicating arteries). Perforator infarction did not occur. CONCLUSION: PED placement is a reasonably safe and effective treatment for intracranial aneurysms. The treatment is promising for aneurysms of unfavorable morphologic features, such as wide neck, large size, fusiform morphology, incorporation of side branches, and posttreatment recanalization, and should be considered a first choice for treating unruptured aneurysms and recurrent aneurysms after previous treatments. SUPPLEMENTAL MATERIAL: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12120422/-/DC1.

Percutaneous placement of a low-profile stent-graft device for aortic dissections.

PURPOSE: The use of stent-grafts has proved to be safe and effective treatment for complicated aortic dissections but usually requires surgical cutdown to accommodate large-profile devices. Preliminary results of the use of a low-profile design that allows percutaneous access are presented. MATERIALS AND METHODS: Fifteen patients with aortic dissection were treated with use of a low-profile stent-graft. Dissection types included Stanford type A (n = 6) and type B (n = 9). The procedures were performed with use of Perclose devices to achieve hemostasis. The stent-graft device was composed of Gianturco stents connected with longitudinal wire struts covered with radially expanded polytetrafluoroethylene. The delivery sheath sizes were 14-20 F. RESULTS: In 87% of patients (13 of 15), the entry tear was excluded completely. Successful femoral closures were achieved in 93% of patients (14 of 15) with use of the suture-mediated devices. In 7% of patients (one of 15), surgical closure of the femoral arteries was required. The rate of pseudoaneurysm occurrence was 7% (one of 15). Hospitalization ranged from 1 to 30 days with a mean duration of 6.5 days. The 30-day mortality rate was 27% (four of 15). In the remaining 11 patients, entry tear sites were excluded and, on follow-up CT examinations, there was thrombosis and retraction of the false lumen and enlargement of the true lumen. CONCLUSION: Preliminary results of the use of a low-profile stent-graft device to treat aortic dissections show that, in most patients, it can be used with a suture-mediated device without surgical exposure of the common femoral artery.