Is a Close Follow-Up Computed Tomography Necessary for Acute Falcine and Tentorial Subdural Hematoma?

OBJECTIVE: This study aimed to assess the changes and values on follow-up computed tomography (F/U-CT) for isolated falcine (F-SDH) and tentorial (T-SDH) subdural hematomas (SDHs). METHOD: Fifty-four cases of isolated F-SDH and/or T-SDH were retrospectively reviewed. Subdural hematoma morphology, mass effect on the adjacent parenchyma, and interval change at F/U-CT were evaluated. Subdural hematoma size was measured parallel and perpendicular to the falx/tentorium (long or short axis, respectively). RESULTS: Short-axis increase on F/U-CT was seen only in 5 F-SDHs (16%) and 7 T-SDHs (19%), with a maximum of a 2-mm increase. Long-axis growth was more prominent and frequent, seen in 18 F-SDH patients (56.2%) and 19 T-SDH patients (51.4%), with maximum change of up to 43 mm. Falcine SDH and T-SDH were ipsilateral and contiguous in 77.8% of patients. Minimal mass effect was seen in 13 patients (24.1%), which was resolved or stable on F/U-CT. Anticoagulation did not affect SDH size. No patients required neurosurgery or died. CONCLUSIONS: Based on our limited data, the current standard of F/U-CT may be unnecessary in patients with isolated F-SDH and/or T-SDH, which expand minimally along the short axis without a significant mass effect. Characteristic anatomic structure of the tentorium and falx, and their connectivity may direct SDH expansion and limit mass effect as well as injury to the adjacent parenchyma.

Initial Presentation of Granulomatosis with Polyangiitis as Progressive Skull Base Osteomyelitis.

A healthy man in his 30s presented with a 2-week history of severe bitemporal pain and pressure. He was initially treated for presumed acute rhinosinusitis, but his symptoms continued to worsen and underwent endoscopic sinus surgery at an outside community facility. He developed left abducens nerve palsy postoperatively, and magnetic resonance imaging (MRI) demonstrated evidence of extensive skull base osteomyelitis. He was initiated on intravenous (IV) broad-spectrum antibiotics but was subsequently found to have prostatic and submandibular sterile fluid collections. The patient subsequently developed new right abducens and left vagal nerve palsies and underwent revision endoscopic sinus surgery. Pathology revealed extensive inflammation, necrotizing granulomas, and evidence of small and medium vessel vasculitis. Extensive laboratory workup was negative, except for anti-PR-3 antibody positivity. Given the characteristic findings on pathology and laboratory findings, the patient was diagnosed with granulomatosis with polyangiitis (GPA). High-dose glucocorticoid therapy as well as rituximab infusion were promptly initiated. He had marked improvement in his symptoms and resolution of his right CN VI palsy but left-sided CN VI and CN X palsies persisted. This patient presented without the typical rhinologic manifestations of GPA, and rather presented with progressive sinusitis, skull base osteomyelitis with associated cranial neuropathies, and aseptic systemic abscesses. Prompt diagnosis of GPA is particularly important in those with otorhinolaryngological manifestations, as early initial immunosuppressive therapy has been linked to lower relapse and mortality rates. Vigilance and early differentiation between GPA and other forms of sinusitis is of critical importance, particularly when symptoms are refractory to standard rhinosinusitis therapies.

Cell-autonomous circadian clock of hepatocytes drives rhythms in transcription and polyamine synthesis.

The circadian clock generates daily rhythms in mammalian liver processes, such as glucose and lipid homeostasis, xenobiotic metabolism, and regeneration. The mechanisms governing these rhythms are not well understood, particularly the distinct contributions of the cell-autonomous clock and central pacemaker to rhythmic liver physiology. Through microarray expression profiling in Met murine hepatocytes (MMH)-D3, we identified over 1,000 transcripts that exhibit circadian oscillations, demonstrating that the cell-autonomous clock can drive many rhythms, and that MMH-D3 is a valid circadian model system. The genes represented by these circadian transcripts displayed both cophasic and antiphasic organization within a protein-protein interaction network, suggesting the existence of competition for binding sites or partners by genes of disparate transcriptional phases. Multiple pathways displayed enrichment in MMH-D3 circadian transcripts, including the polyamine synthesis module of the glutathione metabolic pathway. The polyamine synthesis module, which is highly associated with cell proliferation and whose products are required for initiation of liver regeneration, includes enzymes whose transcripts exhibit circadian oscillations, such as ornithine decarboxylase and spermidine synthase. Metabolic profiling revealed that the enzymatic product of spermidine synthase, spermidine, cycles as well. Thus, the cell-autonomous hepatocyte clock can drive a significant amount of transcriptional rhythms and orchestrate physiologically relevant modules such as polyamine synthesis.

Emergency Radiology: An Underappreciated Source of Liability Risk.

PURPOSE: While several studies analyze radiology malpractice lawsuits, none specifically examines the site of service. The purpose of this study is to estimate the relative likelihood of a lawsuit arising from a radiology study performed in emergency (ED), inpatient (IP) and outpatient (OP) settings. METHODS: Referrals from a malpractice review consulting company over a six year period were compared to the 2016 Medicare Part B file and stratified by site of service. The proportion of exams for each site of service was estimated, and using absolute differences in proportions and odds ratios (ORs), differences in the place of service were calculated. RESULTS: The Cleareview cohort contained 25 (17%) IP, 56 (38%) OP, and 68 (46%) ED exams. In 2016, Medicare assigned benefits for 27,009,053 (20%) IP, 84,075,848 (62%) OP and 23,964,794 (18%) ED exams. The ORs (Cleareview: Medicare) of the ED to IP, OP, and IP+OP were 3.07 (95% CI: 1.56-6.03), 4.26 (95% CI: 2.76-6.59), 3.89 (95% CI: 2.60-5.83), respectively. By contrast, the OR for IP:OP between Cleareview and Medicare was not significantly different than 1 (OR: 1.39, 95% CI: 0.68-2.83, P = .38). DISCUSSION: Radiological studies performed in the ED accounted for a disproportionate number of liability claims against radiologists. Further study is warranted to confirm this finding with a more robust data set.

Combining results of microarray experiments: a rank aggregation approach.

As technology for microarray analysis becomes widespread, it is becoming increasingly important to be able to compare and combine the results of experiments that explore the same scientific question. In this article, we present a rank-aggregation approach for combining results from several microarray studies. The motivation for this approach is twofold; first, the final results of microarray studies are typically expressed as lists of genes, rank-ordered by a measure of the strength of evidence that they are functionally involved in the disease process, and second, using the information on this rank-ordered metric means that we do not have to concern ourselves with data on the actual expression levels, which may not be comparable across experiments. Our approach draws on methods for combining top-k lists from the computer science literature on meta-search. The meta-search problem shares several important features with that of combining microarray experiments, including the fact that there are typically few lists with many elements and the elements may not be common to all lists. We implement two meta-search algorithms, which use a Markov chain framework to convert pairwise preferences between list elements into a stationary distribution that represents an aggregate ranking (Dwork et al, 2001). We explore the behavior of the algorithms in hypothetical examples and a simulated dataset and compare their performance with that of an algorithm based on the order-statistics model of Thurstone (Thurstone, 1927). We apply all three algorithms to aggregate the results of five microarray studies of prostate cancer.

Parenchymal Volumetric Assessment as a Predictive Tool to Determine Renal Function Benefit of Nephron-Sparing Surgery Compared with Radical Nephrectomy.

PURPOSE: To develop a preoperative prediction model using a computer-assisted volumetric assessment of potential spared parenchyma to estimate the probability of chronic kidney disease (CKD, estimated glomerular filtration rate [eGFR] <60 mL/min/1.73 m(2)) 6 months from extirpative renal surgery (nephron-sparing surgery [NSS] or radical nephrectomy [RN]). PATIENTS AND METHODS: Retrospective analysis of patients who underwent NSS or RN at our institution from January 2000 to June 2013 with a compatible CT scan 6-month renal function follow-up was performed. Primary outcome was defined as the accuracy of 6-month postoperative eGFR compared with actual postoperative eGFR based on root mean square error (RMSE). Models were constructed using renal volumes and externally validated. A clinical tool was developed on the best model after a given surgical procedure using area under the curve (AUC). RESULTS: We identified 130 (51 radical, 79 partial) patients with a median age of 58 years (interquartile range [IQR] 48-67) and preoperative eGFR of 82.1 (IQR 65.9-104.3); postoperative CKD (eGFR <60) developed in 42% (55/130). We performed various linear regression models to predict postoperative eGFR. The Quadratic model was the highest performing model, which relied only on preoperative GFR and the volumetric data for a RMSE of 15.3 on external validation corresponding to a clinical tool with an AUC of 0.89. CONCLUSION: Volumetric-based assessment provides information to predict postoperative eGFR. A tool based on this equation may assist surgical counseling regarding renal functional outcomes before renal tumor surgical procedures.