Effectiveness of chlorhexidine diacetate and povidone-iodine in antiseptic preparation of the canine external ear canal prior to total ear canal ablation with bulla osteotomy procedure: A preliminary study.

OBJECTIVE: This article is a preliminary study to compare the ability of 0.05% chlorhexidine diacetate (CD) and 1% povidone-iodine (PI) solutions to reduce bacterial contamination on the canine external ear canal during initial patient preparation and comparison of the incidence of immediate tissue reactions. STUDY DESIGN: The study is a multi-institutional, randomised, clinical prospective study. ANIMALS OR SAMPLE POPULATION: Dogs (n = 19) undergoing total ear canal ablation with bulla osteotomy (TECABO). METHODS: The external ear of each dog was cleaned with the assigned antiseptic solution. Culture of the ear was performed by standard techniques to semi-quantitatively evaluate bacterial growth and to identify bacterial organisms pre- and post-antiseptic use. RESULTS: Both antiseptic groups showed a significant reduction in bacterial growth score (BGS) between pre- and post-antiseptic use (CD p = 0.009, PI p = 0.005). There was no difference in the reduction of BGS between CD and PI solutions (p = 0.53). Minor adverse skin reactions occurred in 25% of cases. There was no significant difference in the occurrence of adverse skin reactions between antiseptics (p = 0.63). CONCLUSION: CD and PI were similarly able to decrease the number of bacteria on the external ear following initial preparation. No difference in the incidence of adverse tissue reactions was found. CLINICAL SIGNIFICANCE: Properly diluted aqueous formulations of either antiseptic may be used for safe preparation limited to the external ear canal of dogs. Additional studies evaluating outcomes such as duration of bacterial inhibition and incidence of surgical site infections are needed to fully elucidate differences between CD and PI antiseptics prior to TECABO.

Post-procedural structural heart CT imaging: TAVR, TMVR, and other interventions.

Transcatheter valve replacement has experienced substantial growth in the past decade and this technique can now be used for any of the four heart valves. Transcatheter aortic valve replacement (TAVR) has overtaken surgical aortic valve replacement. Transcatheter mitral valve replacement (TMVR) is often performed in pre-existing valves or after prior valve repair, although numerous devices are undergoing trials for replacement of native valves. Transcatheter tricuspid valve replacement (TTVR) is similarly under active development. Lastly, transcatheter pulmonic valve replacement (TPVR) is most often used for revision treatment of congenital heart disease. Given the growth of these techniques, radiologists are increasingly called upon to interpret post-procedural imaging for these patients, particularly with CT. These cases will often arise unexpectedly and require detailed knowledge of potential post-procedural appearances. We review both normal and abnormal post-procedural findings on CT. Certain complications-device migration or embolization, paravalvular leak, or leaflet thrombosis-can occur after replacement of any valve. Other complications are specific to each type of valve, including coronary artery occlusion after TAVR, coronary artery compression after TPVR, or left ventricular outflow tract obstruction after TMVR. Finally, we review access-related complications, which are of particular concern due to the requirement of large-bore catheters for these procedures.

Accuracy of needle arthroscopy for the diagnosis of medial meniscal tears in dogs with cranial cruciate ligament rupture.

OBJECTIVE: To determine the accuracy of needle arthroscopy (NA) for the diagnosis of medial meniscal tears in dogs with cranial cruciate ligament rupture (CCLR). STUDY DESIGN: Prospective clinical trial. ANIMALS: Twenty-six client-owned dogs. METHODS: Dogs with CCLR and scheduled to undergo tibial plateau leveling osteotomy were recruited for the study. Needle arthroscopy was performed by an experienced surgeon; the same dog subsequently underwent standard arthroscopy (SA) by another experienced surgeon who was blinded to the NA findings. The SA arthroscopy findings were used as the gold standard. Arthroscopy time, visibility of the menisci, ability to probe the menisci, and the presence of meniscal tears were recorded for both arthroscopies. The degree of lameness before and after NA was subjectively quantified. RESULTS: The sensitivity and specificity to diagnose medial meniscal tears with NA was 95% and 100%, respectively. Visibility of the menisci was lower (P < .01), probing of the lateral meniscus was harder (P = .0017), and procedure time was shorter (P = .073) with NA when compared to SA. The lameness scores did not differ before and after NA (P = .25). CONCLUSION: Needle arthroscopy could be performed rapidly with low morbidity, and had high accuracy for detecting medial meniscal tears in dogs with CCLR. CLINICAL SIGNIFICANCE: Needle arthroscopy is a promising minimally invasive technique for diagnosing medial meniscal tears in dogs with CCLR.

Prone Chest Radiographs: Distinguishing Features and Identification of Support Devices.

PURPOSE: Prone position is known to improve acute lung injury, and chest radiographs are often necessary to monitor disease and confirm support device placement. However, there is a paucity of literature regarding radiographs obtained in this position. We evaluated prone radiographs for distinguishing features and ability to identify support devices. METHODS: Pairs of prone and supine radiographs obtained during the COVID-19 pandemic were assessed retrospectively. IRB approval and waiver of informed consent were obtained. Radiographs were assessed for imaging adequacy, distinguishing features, and support device identification (endotracheal tube, enteric tube, or central line). Radiographs were reviewed by ≥ 2 cardiothoracic radiologists. RESULTS: Radiographs from 81 patients (63yo ± 13, 30% women) were reviewed. Prone and supine radiographs were comparable for imaging the lung bases (81% vs. 90%, p = 0.35) and apices (93% vs. 94%, p = 1); prone radiographs more frequently had significant rotation (36% vs. 19%, p = 0.021). To identify prone technique, scapula tip located beyond the rib border was 89% sensitive (95%CI 80-95%) and 85% specific (76-92%), and a fundal stomach bubble was 44% sensitive (33-56%) and 90% specific (81-96%). For women, displaced breast shadow was 46% sensitive (26-67%) and 92% specific (73-99%). Prone and supine radiographs each identified > 99% of support devices. Prone exams trended toward increased rate of malpositioned device (12% vs. 6%, p = 0.07). CONCLUSION: Scapula position reliably distinguishes prone from supine position; fundal stomach bubble or displaced breast shadow is specific for prone position. Prone radiographs reliably identify line and tube position, which is particularly important as prone patients appear at increased risk for malpositioned devices.

A comparison of pulmonary embolism in pediatric and adult patients with acute COVID-19.

BACKGROUND: COVID-19 is associated with pulmonary embolism (PE) in adults. However, the rate of PE in pediatric patients with acute COVID-19 evaluated by CT pulmonary angiography (CTPA) has not been evaluated. OBJECTIVE: Determine PE rate in pediatric patients with acute COVID-19 and compare to adults. MATERIALS AND METHODS: A retrospective review of CTPA studies, performed between March 2020 and January 2021 on pediatric patients with acute COVID-19, but not MIS-C, was performed. CTPAs performed on an adult cohort of acute COVID-19 patients during April 2020 were reviewed for comparison. Pediatric and chest radiologists independently reviewed CTPAs of pediatric and adult patients, respectively. RESULTS: Of the 355 acute COVID-19 pediatric patients treated during the study period, 14 (16.6 ± 4.8y, median-18.5y, 64% female) underwent CTPA. Of the 1868 acute COVID-19 adults treated during two weeks in April 2020, 50 (57.2 ± 17.0y, median-57.0y, 42% female) underwent CTPA. The PE rate was 14% in the pediatric group (2 patients) and 18% in the adult group (9 patients) (p = 1.0). Both pediatric patients with PE were obese, over 18y, and had asthma, diabetes mellitus, or hypertension. No child<18y with acute COVID-19 had PE. In the adult cohort, higher alanine-aminotransferase and D-dimer levels were associated with PE (p = 0.04 and p = 0.004, respectively). CONCLUSION: Despite similar PE rates in pediatric and adult patients, PE occurred in acute COVID-19 pediatric patients who were >18y, obese, and had at least 1 comorbidity. Children <18y with COVID-19 did not have PE.

Use of a circular fixator construct to facilitate closed reduction and percutaneous stabilization of a distal femoral physeal fracture in a dog.

Background: Fractures of the distal femoral physis are the most common physeal fracture sustained by skeletally immature dogs. Reduction and stabilization of these fractures can sometimes be achieved through closed reduction, primarily in fractures that are nominally displaced. Circular external fixator constructs have been used to assist in indirect, closed reduction of fractures at other anatomic locations in dogs and this report describes application of this method to reduce a displaced Salter-Harris type II fracture of the distal femur in a 1-year-old dog. Case Description: A 1-year-old female spayed Akita was referred for treatment of a Salter-Harris type II fracture of the right distal femur. The epiphyseal segment was laterally and slightly caudally displaced. Multiple attempts to manually reduce the fracture during surgery were unsuccessful, so a two-ring circular external fixator construct was applied to facilitate distraction and reduction. The construct was applied by placing a medial-to-lateral Kirschner wire in both the mid-femoral diaphysis and in the distal femoral epiphysis. Distraction of the construct provided sufficient separation of the fracture segments to facilitate near anatomic reduction. The fracture was stabilized with two percutaneously placed Steinmann pins placed in Rush fashion. Radiographic union was confirmed 5 weeks after surgery. The dog was not lame and was bearing more weight on the right pelvic limb, as assessed using force plate analysis, 9 months following surgery. Goniometric measurements of stifle range of motion and thigh muscle circumference were similar between the pelvic limbs. Conclusion: Application of a two-ring circular construct would appear to be useful to facilitate closed reduction and percutaneous stabilization of distal femoral physeal fractures.

Diagnostic Performance of Pulmonary Embolism Imaging in Patients with History of Asthma.

Asthma and pulmonary embolism (PE) can present with overlapping symptoms, and distinguishing between these 2 conditions can be challenging. Asthma may limit imaging for PE because of either worsened ventilation defects on ventilation-perfusion scanning (VQ) or increased motion artifacts on CT pulmonary angiography (CTPA). Methods: We identified adults evaluated for PE with VQ or CTPA from 2012 to 2016. Patients with chronic lung disease (other than asthma) were excluded. Studies were classified as negative, positive, or nondiagnostic. Follow-up of negative cases was reviewed to determine the rate of repeat exams (within 1 wk) and the false-negative rate (defined as diagnosis of venous thromboembolism within 90 d). Results: We reviewed 19,412 adults (aged 52 ± 18 y, 70% women) evaluated for PE (60% with VQ, 40% with CTPA); 23% had a history of asthma. Nondiagnostic results were comparable for those with and without asthma for both VQ (asthma, 3.3%; nonasthma, 3.8%; P = 0.223) and CTPA (asthma, 1.6%; nonasthma, 1.5%; P = 0.891). A history of asthma was not associated with a higher rate of repeat exams after negative imaging for VQ (asthma, 1.9%; nonasthma, 2.1%; P = 0.547) or CTPA (asthma, 0.6%; nonasthma, 0.6%; P = 0.796), nor was a history of asthma associated with a higher false-negative rate for VQ (asthma, 0.4%; nonasthma, 0.9%; P = 0.015) or CTPA (asthma, 1.9%; nonasthma 1.5%; P = 0.347). Conclusion: A history of asthma in the preceding 10 y was not associated with impaired diagnostic performance of PE imaging for either VQ or CTPA.

CT Scans Obtained for Nonpulmonary Indications: Associated Respiratory Findings of COVID-19.

Background Atypical manifestations of coronavirus disease 2019 (COVID-19) are being encountered as the pandemic unfolds, leading to non-chest CT scans that may uncover unsuspected pulmonary disease. Purpose To investigate patients with primary nonrespiratory symptoms who underwent CT of the abdomen or pelvis or CT of the cervical spine or neck with unsuspected findings highly suspicious for pulmonary COVID-19. Materials and Methods This retrospective study from March 10, 2020, to April 6, 2020, involved three institutions, two in a region considered a hot spot (area of high prevalence) for COVID-19. Patients without known COVID-19 were included who presented to the emergency department (ED) with primary nonrespiratory (gastrointestinal or neurologic) symptoms, had lung parenchymal findings suspicious for COVID-19 at non-chest CT but not concurrent chest CT, and underwent COVID-19 testing in the ED. Group 1 patients had reverse transcription polymerase chain reaction (RT-PCR) results obtained before CT scan reading (COVID-19 suspected on presentation); group 2 had RT-PCR results obtained after CT scans were read (COVID-19 not suspected). Presentation and imaging findings were compared, and outcomes were evaluated. Descriptive statistics and Fisher exact tests were used for analysis. Results Group 1 comprised 62 patients (31 men, 31 women; mean age, 67 years ±17 [standard deviation]), and group 2 comprised 57 patients (28 men, 29 women; mean age, 63 years ± 16). Cough and fever were more common in group 1 (37 of 62 [60%] and 29 of 62 [47%], respectively) than in group 2 (nine of 57 [16%] and 12 of 57 [21%], respectively), with no significant difference in the remaining symptoms. There were 101 CT scans of the abdomen or pelvis and 18 CT scans of the cervical spine or neck. In group 1, non-chest CT findings provided the initial evidence of COVID-19-related pneumonia in 32 of 62 (52%) patients. In group 2, the evidence was found in 44 of 57 (77%) patients. Overall, the most common CT findings were ground-glass opacity (114 of 119, 96%) and consolidation (47 of 119, 40%). Major interventions (vasopressor medication or intubation) were required for 29 of 119 (24%) patients, and 27 of 119 (23%) died. Patients who underwent CT of the cervical spine or neck had worse outcomes than those who underwent abdominal or pelvic CT (P = .01). Conclusion In a substantial percentage of patients with primary nonrespiratory symptoms who underwent non-chest CT, CT provided evidence of coronavirus disease 2019-related pneumonia. © RSNA, 2020.

Radiation dose monitoring in pediatric fluoroscopy: comparison of fluoroscopy time and dose-area product thresholds for identifying high-exposure cases.

BACKGROUND: Fluoroscopy time has been used as a surrogate for radiation dose monitoring in pediatric fluoroscopy; however it does not account for factors such as magnification or collimation. Dose-area product (DAP) is a more accurate measure of radiation exposure but its dependence on patient weight and body-part thickness is a challenge in children of varying ages. OBJECTIVE: To determine whether fluoroscopy time and DAP produce concurrent results when they are used to identify high-exposure cases, and to establish radiation dose thresholds for our institution. MATERIALS AND METHODS: During a 2-year period we prospectively monitored pediatric fluoroscopy studies performed at the Children's Hospital at Montefiore. We recorded study type, fluoroscopy time, DAP, patient age, weight and height. We then calculated 90th percentile fluoroscopy time and DAP thresholds for weight and age. RESULTS: We evaluated 1,011 cases (453 upper gastrointestinal [UGI] series, 266 voiding cystourethrograms [VCUGs], 120 contrast enemas, 108 speech studies, and 64 esophagrams). Fluoroscopy time demonstrated moderate correlation with DAP (rs=0.45, P<0.001, Spearman rank). DAP strongly correlated with patient weight (rs=0.71, P<0.001) and age (rs=0.70, P<0.001). Concordance of cases exceeding 90th percentile thresholds for fluoroscopy time and DAP were κ=0.27 for UGI series and κ=0.49 for VCUG for weight-based cutoffs, and κ=0.36 for UGI series and κ=0.40 for VCUG for age-based cutoffs. CONCLUSION: The limited correlation of fluoroscopy time with DAP suggests these methods are not equivalent for dose monitoring. However, the strong correlation of DAP with patient weight and age presents a challenge for establishing DAP thresholds in children, who range widely in size. Despite controlling for weight or age, there was limited overlap of cases exceeding the 90th percentile threshold for fluoroscopy time and DAP. This further reinforces the non-overlapping outcome of these two methods and indicates that fluoroscopy time might be inadequate for dose monitoring.

Sore Throat, Fever, Septic Emboli, and Acute Respiratory Distress Syndrome: A Case of Lemierre Syndrome.

Lemierre's syndrome is an acute oropharyngeal infection with a secondary septic thrombophlebitis of the internal jugular vein (IVJ) that was first reported in literature in 1936. It involves the progression of disease from a focal suppurative peritonsillar infection to a local septic thrombophlebitis with hematogenous progression to and distant septic emboli. It is a rare and potentially fatal syndrome requiring prompt diagnosis and management. We present the case progression of an 18-year-old male who presented to our hospital with resolved sore throat, fever, and chest discomfort who experienced a sharp clinical decline. His case, physical exam, laboratory abnormalities, and radiologic studies highlight important facets of this rare but important syndrome.

Radiation Dose and Procedure Time for 994 CT-guided Spine Pain Control Procedures.

BACKGROUND: Image guidance for spine pain control procedures, including epidural steroid injection, nerve root block, and facet block, can be performed with either computed tomography (CT) or conventional fluoroscopy. CT has the advantage of improved anatomic localization and use of air for contrast; however, there are concerns that CT leads to higher radiation dose and longer procedure time. OBJECTIVE: To evaluate procedure time and radiation dose for multiple types of spine pain control procedures performed under CT guidance. STUDY DESIGN: Retrospective evaluation. SETTING: Department of radiology in single academic medical center. METHODS: Institutional review board approval was obtained. We reviewed CT-guided spine procedures performed over a 12-month period from January 2012 to December 2012. Procedure type, procedure time, and dose-length product were recorded. Patient age and gender were recorded for each case; additionally, demographic and medical history data were obtained for a sub-group of patients. RESULTS: Nine hundred ninety-four studies (performed in 699 patients) were reviewed, including 585 epidural steroid injections, 228 nerve root blocks, and 90 facet blocks. For all studies, procedure time averaged 7:34 ± 5:05, and dose-length product averaged 75 mGy·cm ± 61. Additional medical history (available for 483 patients) revealed high rate of obesity (body mass index [BMI] = 30 ± 6.8, with 76% of patients overweight [BMI > 25] and 42% obese [BMI > 30]), and frequent medical comorbidities (including hypertension [n = 179], diabetes [n = 101], renal failure [n = 30], and heart failure [n = 17]). LIMITATIONS: This study was performed retrospectively, and limited to a single institution. CONCLUSION: These findings add to the growing evidence that CT guidance is a safe and effective technique for epidural steroid injection. These results further demonstrate that other spine intervention procedures, including nerve root block and facet block, can also be performed under CT guidance with short procedure time and reasonable levels of radiation exposure. This approach can be effectively used in a patient population with a high rate of obesity and medical comorbidities.

GAD67 deficiency in parvalbumin interneurons produces deficits in inhibitory transmission and network disinhibition in mouse prefrontal cortex.

In mammalian neocortex, the delicate balance of neural circuits is regulated by a rich repertoire of inhibitory control mechanisms mediated by diverse classes of GABAergic interneurons. A key step common to all GABAergic neurons is the synthesis of GABA, catalyzed by 2 isoforms of glutamic acid decarboxylases (GAD). Among these, GAD67 is the rate-limiting enzyme. GAD67 level is regulated by neural activity and is altered in multiple neuropsychiatric disorders. The significance of altered GAD67 levels on inhibitory transmission, however, remains unclear. The presence of GAD65, postsynaptic GABA receptor regulation, and the diversity of cortical interneurons make the link from GAD67 levels to GABA transmission less than straightforward. Here, we selectively removed one allele of the GAD67 gene, Gad1, in PV interneurons in juvenile mice. We found substantial deficits in transmission from PV to pyramidal neurons in prefrontal cortex, along with increases of pyramidal cell excitability and excitation/inhibition balance in PV cells. Synaptic deficits recovered in adult mice, suggesting engagement of homeostatic and compensatory mechanisms. These results demonstrate that GAD67 levels directly influence synaptic inhibition. Thus, GAD67 deficiency in PV cells likely contributes to cortical dysfunction in disease states; the reversibility of synaptic deficits suggests nonpermanent damage to inhibitory circuitry.

Cortical glutamic acid decarboxylase 67 deficiency results in lower cannabinoid 1 receptor messenger RNA expression: implications for schizophrenia.

BACKGROUND: Levels of cannabinoid 1 receptor (CB1R) messenger RNA (mRNA) and protein, which are expressed most heavily in the cholecystokinin class of γ-aminobutyric acid (GABA) neurons, are lower in the dorsolateral prefrontal cortex in schizophrenia, and the magnitude of these differences is strongly correlated with that for glutamic acid decarboxylase 67 (GAD(67)) mRNA, a synthesizing enzyme for GABA. However, whether this correlation reflects a cause-effect relationship is unknown. METHODS: Using quantitative in situ hybridization, we measured CB1R, GAD(67), and diacylglycerol lipase alpha (the synthesizing enzyme for the endocannabinoid 2-arachidonoylglycerol) mRNA levels in the medial prefrontal cortex of genetically engineered GAD(67) heterozygous (GAD(67)(+/-)), CB1R heterozygous (CB1R(+/-)), CB1R knockout (CB1R(-/-)), and matched wild-type mice. RESULTS: In GAD(67)(+/-) mice, GAD(67) and CB1R mRNA levels were significantly reduced by 37% and 16%, respectively, relative to wild-type mice and were significantly correlated across animals (r = .61; p = .01). In contrast, GAD(67) mRNA levels were unaltered in CB1R(+/-) andCB1R(-/-) mice. Expression of diacylglycerol lipase alpha mRNA, which is not altered in schizophrenia, was also not altered in any of the genetically engineered mice. CONCLUSIONS: The findings that reduced GAD(67) mRNA expression can induce lower CB1R mRNA expression support the hypothesis that lower cortical levels of CB1Rs in schizophrenia may partially compensate for deficient GAD(67)-mediated GABA synthesis by reducing endogenous cannabinoid suppression of GABA release.

Distinct maturation profiles of perisomatic and dendritic targeting GABAergic interneurons in the mouse primary visual cortex during the critical period of ocular dominance plasticity.

In the rodent primary visual cortex, maturation of GABA inhibitory circuitry is regulated by visual input and contributes to the onset and progression of ocular dominance (OD) plasticity. Cortical inhibitory circuitry consists of diverse groups of GABAergic interneurons, which display distinct physiological properties and connectivity patterns. Whether different classes of interneurons mature with similar or distinct trajectories and how their maturation profiles relate to experience dependent development are not well understood. We used green fluorescent protein reporter lines to study the maturation of two broad classes of cortical interneurons: parvalbumin-expressing (PV) cells, which are fast spiking and innervate the soma and proximal dendrites, and somatostatin-expressing (SOM) cells, which are regular spiking and target more distal dendrites. Both cell types demonstrate extensive physiological maturation, but with distinct trajectories, from eye opening to the peak of OD plasticity. Typical fast-spiking characteristics of PV cells became enhanced, and synaptic signaling from PV to pyramidal neurons became faster. SOM cells demonstrated a large increase in input resistance and a depolarization of resting membrane potential, resulting in increased excitability. While the substantial maturation of PV cells is consistent with the importance of this source of inhibition in triggering OD plasticity, the significant increase in SOM cell excitability suggests that dendrite-targeted inhibition may also play a role in OD plasticity. More generally, these results underscore the necessity of cell type-based analysis and demonstrate that distinct classes of cortical interneurons have markedly different developmental profiles, which may contribute to the progressive emergence of distinct functional properties of cortical circuits.

Maturation of GABAergic inhibition promotes strengthening of temporally coherent inputs among convergent pathways.

Spike-timing-dependent plasticity (STDP), a form of Hebbian plasticity, is inherently stabilizing. Whether and how GABAergic inhibition influences STDP is not well understood. Using a model neuron driven by converging inputs modifiable by STDP, we determined that a sufficient level of inhibition was critical to ensure that temporal coherence (correlation among presynaptic spike times) of synaptic inputs, rather than initial strength or number of inputs within a pathway, controlled postsynaptic spike timing. Inhibition exerted this effect by preferentially reducing synaptic efficacy, the ability of inputs to evoke postsynaptic action potentials, of the less coherent inputs. In visual cortical slices, inhibition potently reduced synaptic efficacy at ages during but not before the critical period of ocular dominance (OD) plasticity. Whole-cell recordings revealed that the amplitude of unitary IPSCs from parvalbumin positive (Pv+) interneurons to pyramidal neurons increased during the critical period, while the synaptic decay time-constant decreased. In addition, intrinsic properties of Pv+ interneurons matured, resulting in an increase in instantaneous firing rate. Our results suggest that maturation of inhibition in visual cortex ensures that the temporally coherent inputs (e.g. those from the open eye during monocular deprivation) control postsynaptic spike times of binocular neurons, a prerequisite for Hebbian mechanisms to induce OD plasticity.