Evaluating thin compression paddles for mammographically compatible ultrasound

We are developing a combined digital mammography/3D ultrasound system to improve detection and/or characterization of breast lesions. Ultrasound scanning through a mammographic paddle could significantly reduce signal level, degrade beam focusing and create reverberations. Thus, appropriate paddle choice is essential for accurate sonographic lesion detection and assessment with this system. In this study, we characterized ultrasound image quality through paddles of varying materials (lexan, polyurethane, TPX, mylar) and thicknesses (0.25 to 2.5 mm). Analytical experiments focused on lexan and TPX, which preliminary results demonstrated were most competitive. Spatial and contrast resolution, side-lobe and range lobe levels, contrast and signal strength were compared with no-paddle images. When the beamforming of the system was corrected to account for imaging through the paddle, the TPX 2.5 mm paddle performed the best. Test objects imaged through this paddle demonstrated < or = 15% reduction in spatial resolution, < or = 7.5 dB signal loss, < or = 3 dB contrast loss and range lobe levels > or = 35 dB below signal maximum over 4 cm. TPX paddles <2.5 mm could also be used with this system, depending on imaging goals. In 10 human subjects with cysts, small CNR losses were observed but were determined to be statistically insignificant. Radiologists concluded that 75% of cysts in through-paddle scans were at least as detectable as in their corresponding direct-contact scans.     

A review of meibography for a refractive surgeon

Refractive surgery has evolved from being a therapeutic correction of high refractive errors to a cosmetic correction. The expectations associated with such a surgery are enormous and one has to anticipate all possible complications and side-effects that come with the procedure and prepare accordingly. The most common amongst these is post-refractive surgery dry eye of which Meibomian gland dysfunction is a commonly associated cause. We present an understanding of various diagnostic imaging modalities that can be used for evaluating meibomian glands which can also serve as a visual aid for patient understanding. We also describe various common conditions which can silently cause changes in the gland architecture and function which are to be considered and evaluated for.     

COVID‐19 in solid organ transplant recipients: Initial report from the US epicenter

Solid organ transplant recipients may be at a high risk for SARS‐CoV‐2 infection and poor associated outcomes. We herein report our initial experience with solid organ transplant recipients with SARS‐CoV‐2 infection at two centers during the first 3 weeks of the outbreak in New York City. Baseline characteristics, clinical presentation, antiviral and immunosuppressive management were compared between patients with mild/moderate and severe disease (defined as ICU admission, intubation or death). Ninety patients were analyzed with a median age of 57 years. Forty‐six were kidney recipients, 17 lung, 13 liver, 9 heart, and 5 dual‐organ transplants. The most common presenting symptoms were fever (70%), cough (59%), and dyspnea (43%). Twenty‐two (24%) had mild, 41 (46%) moderate, and 27 (30%) severe disease. Among the 68 hospitalized patients, 12% required non‐rebreather and 35% required intubation. 91% received hydroxychloroquine, 66% azithromycin, 3% remdesivir, 21% tocilizumab, and 24% bolus steroids. Sixteen patients died (18% overall, 24% of hospitalized, 52% of ICU) and 37 (54%) were discharged. In this initial cohort, transplant recipients with COVID‐19 appear to have more severe outcomes, although testing limitations likely led to undercounting of mild/asymptomatic cases. As this outbreak unfolds, COVID‐19 has the potential to severely impact solid organ transplant recipients.     

Chronic Pancreatitis with Benign Biliary Obstruction: Management Issues

Background

Benign biliary obstruction (BBO) is an important complication in patients with advanced chronic pancreatitis (CP). Its presentation varies from an incidental finding to overt jaundice. Thus it presents certain management issues. The present study was therefore performed to analyze the clinical presentation and management of biliary obstruction in patients with CP.

Methods

Retrospective analysis was performed from a prospectively collected database of 155 CP patients managed at our institute from October 2003 to June 2012.

Results

Among 43 (28 %) CP patients with biliary obstruction, 3 patients had evidence of malignancy on follow-up examination and were excluded from the final analysis. The various presentations include chronic nonprogressive elevation of serum alkaline phosphatase (SAP) (n = 15), a progressive increase in SAP with episodes of jaundice (n = 17), and persistent jaundice (n = 8). Of 15 patients with chronic nonprogressive elevation of SAP, 5 were managed conservatively, and the remaining 10 underwent only a pancreatic drainage procedure. During a median follow-up of 41 months (range 11–90 months), none of the 15 patients developed complications related to biliary obstruction. All patients with progressive increase in SAP levels and persistent jaundice underwent the biliary drainage procedure [choledochojejunostomy (CDJ, n = 20) and choledochoduodenostomy (CDD, n = 3)]. During a median follow-up of 30 months (range 10–89 months), two patients died of unrelated causes and two patients had an asymptomatic elevation of SAP.

Conclusions

BBO is common in patients with CP; however, biliary drainage is not indicated for chronic nonprogressive elevation of SAP. In patients with a progressive increase in SAP or persistent jaundice, both CDJ and CDD provide effective biliary drainage.     

The link between dopamine function and apathy in cannabis users: an [18F]-DOPA PET imaging study

Rationale

Cannabis is the most widely used illicit drug in the world, and regular use has been associated with reduced motivation, i.e. apathy. Regular long-term cannabis use has been associated with reduced dopamine synthesis capacity. The mesolimbic dopaminergic system mediates the processing of incentive stimuli by modifying their motivational value, which in turn is modulated by endocannabinoid signalling. Thus, it has been proposed that dopaminergic dysfunction underlies the apathy associated with chronic cannabis use.

Objectives

The aim of this study was to examine the relationship between dopaminergic function and subjective apathy in cannabis users.

Methods

We measured dopamine synthesis capacity (indexed as the influx rate constant K _i ^cer ) via 3,4-dihydroxy-6-[¹⁸F]-fluoro-l-phenylalanine positron emission tomography and subjective apathy using the self-rated Apathy Evaluation Scale (AES-S) in 14 regular cannabis users.

Results

All subjects scored in excess of 34 points on the AES-S (median [interquartile range] 59.5 [7.5]), indicative of significant apathy based on normative data. K _i ^cer was inversely correlated to AES-S score in the whole striatum and its associative functional subdivision (Spearman’s rho?=??0.64, p?=?0.015 [whole striatum]; rho?=??0.69, p?=?0.006 [associative]) but not in the limbic or sensorimotor striatal subdivisions. There were no significant relationships between AES-S and current cannabis consumption (rho?=?0.28, p?=?0.34) or age of first cannabis use (rho?=?0.25, p?=?0.40).

Conclusions

These findings indicate that the reduction in striatal dopamine synthesis capacity associated with chronic cannabis use may underlie reduced reward sensitivity and amotivation associated with chronic cannabis use.