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The aim of the study was to correlate the sonographic features of Botox A injection in rat submandibular gland with the histopathological changes. Fifteen Wistar albino rats were randomly assigned to 2 groups. Group 1 (control group) consisted of 5 animals not given any substance. Group 2 was divided as "a" and "b" each consisting of 5 animals. A median cervical incision has been performed to the rats in group 2 and 2.5 U Botulinum toxin A reconstituted 0.1 ml physiologic saline was injected into the right gland. Sonograms were obtained before the application, at the first day of the Botox A application, in addition to group 2a on the 14th day, and on 28th day to group 2b. Gland size was lower in group 2a and 2b comparing to control group. The gland size of group 2b was lower than group 2a. There was no change in vascularization. There was no other histopathological change except lymphocytic infiltration in group 2. It was observed that Botox A injection does not have a direct effect on the cells in submandibular gland but it causes a homogenic shrinking in gland size without atrophy.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is transmitted from person to person, mainly by respiratory droplets and surface contact, with high incidence, high concealment, and rapid transmission (1). Patients may become a source of infection not only when they are symptomatic but also during the incubation or the recovery period (2). Coronavirus disease 2019 (COVID-19), the pneumonia that is caused by SARS-CoV-2, has therefore become a serious worldwide public health threat. Accurate and timely diagnosis of the disease is critical for effective treatment, better survival, and control of disease spread. Currently, COVID-19 pneumonia is diagnosed by the reverse transcriptase-polymerase chain reaction (RT-PCR) test. However, the high false-negative rate for the PURPOSE The widespread use of computed tomography (CT) in COVID-19 may cause adverse biological effects. Many recommend to minimize radiation dose while maintaining diagnostic quality. This study was designed to evaluate the difference between findings of COVID-19 pneumonia on standard and low-dose protocols to provide data on the utility of the latter during initial imaging of COVID-19. METHODSPatients suspected of having COVID-19 were scanned with a 128-slices scanner using two consecutive protocols in the same session (standard-dose scan: 120 kV and 300 mA; low-dose scan: 80 kV and 40 mA). Dose data acquisition and analysis was performed using an automated software. High and low-dose examinations were anonymized, shuffled and read by two radiologist with consensus according to a highly structured reporting format that was primarily based on the consensus statement of the RSNA. Accordingly, 8 typical, 2 indeterminate, and 7 atypical findings were investigated. Cases were then assigned to one of the categories:McNemar test was used to analyze the number of disagreements between standard and low-dose scans regarding paired proportions of structured findings. Intertest reliability was tested using kappa coefficient. RESULTSThe study included 740 patients with a mean age of 44.05±16.59 years. The median (minimummaximum) dose level for standard protocol was 189.98 mGy•cm (98.20-493.54 mGy•cm) and for low-dose protocol was 15.59 mGy•cm (11.59-32.37 mGy•cm) differing by -80 and -254 mGy•cm from pan-European diagnostic reference levels. Only two findings for typical, one finding for indeterminate, and three findings for atypical categories were statistically similar (p > 0.05). The difference in other categories resulted in significantly different final diagnosis for COVID-19 (p < 0.001). Overall, 626 patients received matching diagnoses with the two protocols. According to intertest reliability analysis, kappa value was found to be 0.669 (p < 0.001) to indicate substantial match. CT with standard-dose had a sensitivity of 94% and a specificity of 72%, while CT with low-dose had a sensitivity of 90% and a specificity of 81%. CONCLUSIONLow kV and mA scans, as used in this study according to scanner manufacturer's global recommendations, may signifi...

BACKGROUND Studies involving superficial facial fat compartments are few in number with conflicting results. Most of them involved small study groups and compared measurements between different populations of young and old subjects either on cadavers or living subjects. OBJECTIVE To clarify volumetric and dimensional changes in midfacial superficial fat compartment retrospectively in patients who underwent a repeat magnetic resonance imaging (MRI) without gross pathology. MATERIALS AND METHODS A total of 70 patients with a mean age of 60 years (range: 33–82 years) and a median elapsed time of 44.5 months (range: 32–64 months) between 2 MRIs were included. Magnetic resonance imaging scans were analyzed in the axial and sagittal planes to obtain measurements of the medial part of the superficial cheek fat. Superficial cheek fat was divided into 3 compartments. Thickness, width, and height were measured, and volumes were calculated for each compartment on both hemifaces. RESULTS Volume and thickness were decreased significantly in all compartments (p < .05). The width was decreased in superior and middle compartments, whereas increased in lower compartment indicating dislocation of the fat tissue (p < .05). Height was also significantly increased (p < .05). A subgroup analysis has shown that there was no significant difference between men and women. CONCLUSION This study clarifies that aging is associated with a significant decrease in superficial midfacial fat tissue volume and thickness both in women and men. The decrease in width in upper and middle compartments, but increase in lower compartment suggests a volume shift within superficial fat tissue.