A randomized trial of diagnostic ultrasound to improve outcomes in focal neuropathies.

INTRODUCTION: Neuromuscular ultrasound is valid, reliable, and accurate, but it is not known whether combining it with electrodiagnostic studies leads to better outcomes in individuals with focal neuropathies. METHODS: One hundred twenty individuals with focal neuropathy, based on history, examination, and electrodiagnosis, were enrolled in this study. All patients underwent neuromuscular ultrasound and were randomized to either have their ultrasound results sent to the referring physician or not have them sent. Outcomes were assessed at 6 months by evaluators blinded to group assignment. RESULTS: The Overall Disability Sum Score and 7 of 8 domains of the Medical Outcomes Study 36-item Short-Form Health Survey (SF-36) showed more improvement in the "report sent" group, although only the general health perception domain was significant (P = 0.005). CONCLUSIONS: Most 6-month outcomes did not reach statistical significance between the 2 groups. However, the "report sent" group had trends toward better outcomes, with significance being reached in the general health perception domain of the SF-36.

Validity and reliability of nerve and muscle ultrasound.

INTRODUCTION: Nerve and muscle ultrasound has been studied in several conditions, but validity and reliability have not been assessed systematically. METHODS: Nerve cross-sectional area and muscle thickness were measured ultrasonographically at several sites in 4 cadavers, which were then dissected, and actual measurements were obtained. To assess intrarater and interrater reliability, between 3 and 5 ultrasonographers, with varying experience levels, made repeated measurements on healthy volunteers. RESULTS: Correlation coefficients for nerve and muscle validity were >0.968 (P < 0.001), and for intrarater reliability were >0.901 (P < 0.001) for still and real-time images. Correlation coefficients for interrater reliability were more varied, but for still images they were all significant at the P < 0.001 (0.542-0.998) level, and for real-time images they were significant at the P < 0.05 level for half the sites (0.243-0.981). CONCLUSION: Overall, nerve and muscle ultrasound is a valid and reliable diagnostic imaging technique.

Quantitative shadowgraphy of aerosol and droplet creation during oscillatory motion of the microkeratome amid COVID-19 and other infectious diseases.

PURPOSE: To quantify the atomization of liquid over the cornea during flap creation using microkeratome using high-speed shadowgraphy. SETTING: Laboratory study. DESIGN: Laboratory investigational study. METHOD: In an experimental setup, flap creation was performed on enucleated goat's eyes (n = 8) mounted on a stand using One Use-Plus SBK Moria microkeratome (Moria SA) to assess the spread of aerosols and droplets using high-speed shadowgraphy. Two conditions were computed. A constant airflow assumed uniform air velocity throughout the room. A decaying jet assumed that local air velocity at the site of measurements was smaller than the exit velocity from the air duct. RESULTS: With the advancement of the microkeratome across the wet corneal surface, the atomization of a balanced salt solution was recorded on shadowgraphy. The minimum droplet size was ∼90 µm. The maximum distance traversed was ∼1.8 m and ∼1.3 m assuming a constant airflow (setting of refractive surgery theater) and decaying jet condition (setting of an operating theater with air-handling unit), respectively. CONCLUSIONS: The microkeratome-assisted LASIK flap creation seemed to cause spread of droplets. The droplet diameters and velocities did not permit the formation of aerosols. Therefore, the risk of transmission of the virus to the surgeon and surgical personnel due to the microkeratome procedure seemed to be low.

Quantitative High-speed Assessment of Droplet and Aerosol From an Eye After Impact With an Air-puff Amid COVID-19 Scenario.

PURPOSE: To quantify aerosol and droplets generated during noncontact tonometry (NCT) and assess the spread distance of the same. METHODOLOGY: This was an experimental study on healthy human volunteers (n=8 eyes). In an experimental setup, NCT was performed on eyes (n=8) of human volunteers under normal settings, with a single and 2 drops of lubricant. High-speed shadowgraphy, frontal lighting technique, and fluorescein analysis were used to detect the possible generation of any droplets and aerosols. Mathematical computation of the spread of the droplets was then performed. RESULTS: In a natural setting, there was no droplet or aerosol production. Minimal splatter along with droplet ejection was observed when 1 drop of lubricant was used before NCT. When 2 drops of lubricant were instilled, a significant amount of fluid ejection in the form of a sheet that broke up into multiple droplets was observed. Some of these droplets traversed back to the tonometer. Droplets ranging from 100 to 500 µm in diameter were measured. CONCLUSIONS: There was no droplet generation during NCT performed in a natural setting. However, NCT should be avoided in conditions with high-tear volume (natural or artificial) as it would lead to droplet spread and tactile contamination.

Propensity and quantification of aerosol and droplet creation during phacoemulsification with high-speed shadowgraphy amid COVID-19 pandemic.

PURPOSE: To study propensity of aerosol and droplet generation during phacoemulsification using high-speed shadowgraphy and quantify its spread amid COVID-19 pandemic. SETTING: Aerosol and droplet quantification laboratory. DESIGN: Laboratory study. METHODS: In an experimental set-up, phacoemulsification was performed on enucleated goat eyes and cadaveric human corneoscleral rims mounted on an artificial anterior chamber. Standard settings for sculpt and quadrant removal mode were used on Visalis 100 (Carl Zeiss Meditec AG). Microincision and standard phacoemulsification were performed using titanium straight tips (2.2 mm and 2.8 mm in diameter). The main wound incisions were titrated equal to and larger than the sleeve size. High-speed shadowgraphy technique was used to detect the possible generation of any droplets and aerosols. The visualization and quantification of size of the aerosols and droplets along with calculation of their spread were the main outcome measures. RESULTS: In longitudinal phacoemulsification using a peristaltic pump device with a straight tip, no aerosol generation was seen in a closed chamber. In larger wounds, there was a slow leak at the main wound. The atomization of balanced salt solution was observed only when the phacoemulsification tip was completely exposed next to the ocular surface. Under this condition, the nominal size of the droplet was approximately 50 µm, and the maximum calculated spread was 1.3 m. CONCLUSIONS: There was no visible aerosol generation during microincision or standard phacoemulsification. Phacoemulsification is safe to perform in the COVID-19 era by taking adequate precautions against other modes of transmission.

A new image representation algorithm inspired by image submodality models, redundancy reduction, and learning in biological vision.

We develop a new biologically motivated algorithm for representing natural images using successive projections into complementary subspaces. An image is first projected into an edge subspace spanned using an ICA basis adapted to natural images which captures the sharp features of an image like edges and curves. The residual image obtained after extraction of the sharp image features is approximated using a mixture of probabilistic principal component analyzers (MPPCA) model. The model is consistent with cellular, functional, information theoretic, and learning paradigms in visual pathway modeling. We demonstrate the efficiency of our model for representing different attributes of natural images like color and luminance. We compare the performance of our model in terms of quality of representation against commonly used basis, like the discrete cosine transform (DCT), independent component analysis (ICA), and principal components analysis (PCA), based on their entropies. Chrominance and luminance components of images are represented using codes having lower entropy than DCT, ICA, or PCA for similar visual quality. The model attains considerable simplification for learning from images by using a sparse independent code for representing edges and explicitly evaluating probabilities in the residual subspace.

Granulomatosis with polyangiitis presenting with pachymeningitis.

OBSERVATIONS: This case report describes a 75 year-old Caucasian male who initially presented with persistent daily headaches. Physical exam elicited multiple cranial nerve palsies. Gadolinium-enhanced brain MRI demonstrated pachymeningitis. Labs revealed elevated proteinase-3 antineutrophil cytoplasmic antibodies (PR3-ANCA) and cytoplasmic antineutrophil cytoplasmic antibodies (c-ANCA), confirming a diagnosis of GPA. CONCLUSION: GPA should be considered in older patients presenting with persistent daily headaches and pachymeningitis. Contrast-enhanced brain MRI is an important diagnostic tool.

Clinical reasoning: acute-onset homonymous hemianopia with hyperglycemia: seeing is believing.

A 32-year-old woman with a history of bipolar disorder, polycystic ovarian syndrome, and hypertension and a 4-year history of uncontrolled type 2 diabetes mellitus (DM) presented with bifrontal headache, elevated blood sugars (>500 mg/dL), and abrupt-onset left homonymous hemianopia upon awakening. Vital signs included temperature 98.0°F, blood pressure 160/89 mm Hg, and heart rate 67 bpm. Neurologic examination showed dense left homonymous hemianopia with macular sparing and without other focal findings.

Diagnostic challenges in movement disorders: Sensory Ataxia Neuropathy Dysarthria and Ophthalmoplegia (SANDO) syndrome.

A woman in her early 60s presented to our Movement Disorders Centre with a 5-year history of progressive peripheral neuropathy, gait instability with falls, blurred vision, cognitive impairment and tremors. The patient was found to have profound sensory ataxia, chronic ophthalmoplegia, dementia with significant deficits in registration and construction and bilateral resting tremor of the hands. Investigations revealed an unremarkable MRI of the brain, negative cerebrospinal fluid studies, and unremarkable chemistries. Nerve conduction studies found a severe sensorimotor axonal polyneuropathy. Genetic testing revealed a compound heterozygous mutation in the POLG1 gene consistent with the diagnosis of Sensory Ataxia Neuropathy Dysarthria and Ophthalmoplegia (SANDO) syndrome.

Biocompatibility of nitinol and stainless steel in the bladder: an experimental study.

PURPOSE: We tested the biocompatibility of nitinol, a nickel titanium alloy, and stainless steel (SS) as bladder implant materials. MATERIALS AND METHODS: Rats received a nitinol implant, an SS implant or were sham controls. Two, 3, 6 and 8 weeks following implantation 24-hour voiding behavior studies were performed to investigate bladder irritation. All animals were sacrificed 8 weeks after implantation and a sample of urine was aspirated for culture. The bladders were examined by light microscopy and scanning electron microscopy (SEM). RESULTS: No visible encrustations or infections were noted in urine. Voiding frequency in the light period 6 weeks after implantation was significantly decreased in the 2 implant groups compared with sham controls. There were no other significant differences in frequency or mean volume per void in the light or dark periods at any time point. Light microscopy demonstrated similar implant tissue effects in all groups with little or no inflammation or fibrosis. Under SEM all implants showed a brittle, amorphous coating devoid of cells. The transition between the urothelium mucosa and the rod was smoother for SS than for nitinol, suggesting an affinity of SS for mucosa. In all nitinol rods discontinuity was present between the mucosa and rod. CONCLUSIONS: Nitinol and SS do not cause more irritation than the effects of surgery alone and the 2 materials seem to be biocompatible in the bladder. Nitinol may be more inert than SS based on SEM results.

Living related small bowel transplantation in children: 3-dimensional computed tomography donor evaluation.

The evaluation of the small bowel vascular anatomy of living small bowel donors (LSBD) is usually performed with conventional angiography (CA). Recently, angio computed tomography (CT) has become a valid study of the vascular anatomy for kidney and liver living donors. We studied the applicability of angio CT with 3-D reconstruction (3-D-ACT) in the evaluation of LSBD. Potential LSBDs for pediatric transplant underwent both CA and 3-D-ACT to evaluate the anatomy of the distal branches of the superior mesenteric artery and vein. Angio-CT was performed with General Electric Lightspeed Scanner. The 3-D reconstruction was performed on the TeraRecon workstation. Adverse reactions, contrast dosage, test duration, invasiveness, hospital-stay, patient discomforts and accuracy were evaluated. Four potential donors (four female; mean age: 30.5 yr; mean BMI: 28.4) underwent both tests. Adverse reactions correlated to contrast agent used (90 mL CA, 150 mL 3-D-ACT) were not reported. CA required a hospitalization of 6 h as opposed to immediate discharge after the 3-D-ACT. The CA required the placement of transfemoral catheter and therefore greater patient discomfort than with 3-D-ACT. The 3-D-ACT arterial images were rated as equivalent to CA, however, 3-D-ACT venous images were rated better than the CA in all cases. CT-angiography with 3-D reconstruction is an acceptable method for vascular evaluation. When compared with routine angiography, it is less invasive, better tolerated and faster, but does require a significantly greater volume of venous contrast. 3-D-ACT also offers a better evaluation of the venous phase, and thus may become the test of choice to evaluate the vascular anatomies of LSBD candidates.