Imaging of COVID-19-associated craniofacial mucormycosis: a black and white review of the "black fungus".

A subset of diabetic COVID-19 patients treated with steroids, oxygen, and/or prolonged intensive care admission develop rhino-orbito-cerebral mucormycosis. Radiologists must have a high index of suspicion for early diagnosis, which prompts immediate institution of antifungal therapy that limits morbidity and mortality. Assessment of disease extent by imaging is crucial for planning surgical debridement. Complete debridement of necrotic tissue improves survival. Imaging features reflect the angioinvasive behaviour of fungal hyphae from the Mucoraceae family, which cause necrotising vasculitis and thrombosis resulting in extensive tissue infarction. Contrast-enhanced magnetic resonance imaging (MRI) is the imaging technique of choice. The classic "black turbinate" on contrast-enhanced imaging represents localised invasive fungal rhinosinusitis (IFRS). A striking radiological feature of disseminated craniofacial disease is non-enhancing devitalised and necrotic soft tissue at the orbits and central skull base. Sinonasal and extrasinonasal non-enhancing lesions in IFRS are secondary to coagulative necrosis induced by fungal elements. Multicompartmental and extrasinonasal tissue infarction is possible without overt bone involvement and caused by the propensity of fungal elements to disseminate from the nasal cavity via perineural and perivascular routes. Fungal vasculitis can result in internal carotid artery occlusion and cerebral infarction. Remnant non-enhancing lesions after surgical debridement portend a poor prognosis. Assessment for the non-enhancing MRI lesion is crucial, as it is a sole independent prognostic factor for IFRS-specific mortality. In this review, we describe common and uncommon imaging presentations of biopsy-proven rhino-orbito-cerebral mucormycosis in a cohort of nearly 40 COVID-19 patients.

The role of COMT polymorphism in modulation of prefrontal activity during verbal fluency in bipolar disorder.

OBJECTIVE: Verbal fluency (VF) impairment is a strong predictor of social functioning in bipolar disorder (BPD). The enzyme catechol-O- methyltransferase (COMT) has a critical role in cognitive responses by modulating dopaminergic activity in the prefrontal cortex (PFC). Here, we investigated the role of COMT polymorphism (i) in VF performance as well as (ii) in modulation of PFC activity during a VF-task in euthymic BPD patients. METHODS: 30 subjects with remitted BPD-I and 23 healthy controls (HCs) were genotyped for COMT Val158Met (rs4680) polymorphism and were compared in a VF-task. PFC activity was measured by 24-Channel Functional Near Infrared Spectroscopy. RESULTS: Bipolar subjects displayed lower VF performance than HCs. During the VF-task, BPD-group displayed higher activity than HCs in the Brocca's area, Premotor-cortex and supplementary motor area (SMA). In the index group, Val/Met polymorphism was associated with higher activity in the left- frontopolar and dorsolateral PFC (DLPFC) during the VF-task. LIMITATIONS: Antipsychotic use may have interfered with the results. CONCLUSIONS: Increased activity in the Brocca's area may represent compensation of low VF performance, whereas hyperactivity in premotor-cortex and SMA may be associated with increased behavioral intention and/or restlessness in BPD. Higher activity in left-frontopolar and DLPC among Val/Met individuals compared to Met-homozygotes may represent less effective prefrontal dopaminergic signaling in Val/Met individuals with BPD.

Comparison of Test Statistics of Nonnormal and Unbalanced Samples for Multivariate Analysis of Variance in terms of Type-I Error Rates.

In this study, we investigate how Wilks' lambda, Pillai's trace, Hotelling's trace, and Roy's largest root test statistics can be affected when the normal and homogeneous variance assumptions of the MANOVA method are violated. In other words, in these cases, the robustness of the tests is examined. For this purpose, a simulation study is conducted in different scenarios. In different variable numbers and different sample sizes, considering the group variances are homogeneous (σ 12 = σ 22 = ⋯ = σ g2) and heterogeneous (increasing) (σ 12 < σ 22 < ⋯<σ g2), random numbers are generated from Gamma(4-4-4; 0.5), Gamma(4-9-36; 0.5), Student's t(2), and Normal(0; 1) distributions. Furthermore, the number of observations in the groups being balanced and unbalanced is also taken into account. After 10000 repetitions, type-I error values are calculated for each test for α = 0.05. In the Gamma distribution, Pillai's trace test statistic gives more robust results in the case of homogeneous and heterogeneous variances for 2 variables, and in the case of 3 variables, Roy's largest root test statistic gives more robust results in balanced samples and Pillai's trace test statistic in unbalanced samples. In Student's t distribution, Pillai's trace test statistic gives more robust results in the case of homogeneous variance and Wilks' lambda test statistic in the case of heterogeneous variance. In the normal distribution, in the case of homogeneous variance for 2 variables, Roy's largest root test statistic gives relatively more robust results and Wilks' lambda test statistic for 3 variables. Also in the case of heterogeneous variance for 2 and 3 variables, Roy's largest root test statistic gives robust results in the normal distribution. The test statistics used with MANOVA are affected by the violation of homogeneity of covariance matrices and normality assumptions particularly from unbalanced number of observations.

Technical update of barbed pharyngoplasty for retropalatal obstruction in obstructive sleep apnoea.

BACKGROUND: Barbed pharyngoplasty aims to reduce lateral retropalatal obstruction by pulling up the soft palate anterolaterally. However, barbed pharyngoplasty can be less efficient in some cases of obstructive sleep apnoea, especially in the presence of an elongated uvula with redundant tissues over it. This paper describes an attempt to overcome this drawback by modifying barbed pharyngoplasty, using a single continuous suture technique. METHODS: Thirty-four patients were assigned to two groups based on the surgical procedure performed. Those with an elongated uvula were treated with modified barbed pharyngoplasty (n = 17); the others were treated with barbed pharyngoplasty (n = 17). Pre- and post-operative quality of life questionnaires, and questionnaires concerning diet, pain and return to activity, were completed. Pre- and post-operative polysomnography was performed as an objective measurement. RESULTS: There was no significant difference between barbed pharyngoplasty and modified barbed pharyngoplasty in terms of outcomes. However, reductions in the apnoea/hypopnea index, Epworth Sleepiness Scale and snoring visual analogue scale scores were greater in the modified barbed pharyngoplasty group. CONCLUSION: Modified barbed pharyngoplasty is a safe and feasible method, and eliminates the need for surgical resection of the redundant soft tissues around the uvula while lifting up the uvula base.

Intracranial Perishunt Catheter Fluid Collections with Edema, a Sign of Shunt Malfunction: Correlation of CT/MRI and Nuclear Medicine Findings.

Fluid collections with edema along the intracranial tract of ventriculoperitoneal shunt catheters in adults are rare and are more frequently seen in children. The imaging appearance of these fluid collections is frequently confusing and presents a diagnostic dilemma. We present 6 cases of adult patients noted to have collections with edema along the tract of ventriculoperitoneal shunt catheters. To our knowledge, there are no previous studies correlating the CT/MR imaging findings with nuclear medicine scans in this entity. We hypothesized that when seen in adults, the imaging findings of a CSF-like fluid collection around the intracranial ventriculoperitoneal shunt catheter on CT/MR imaging may suggest areas of CSF accumulation with interstitial edema. It is important to recognize this rare ventriculoperitoneal shunt complication in adults to prevent misdiagnosis of an abscess or cystic tumor.

Thiol/disulphide homeostasis in Bell's palsy as a novel pathogenetic marker.

OBJECTIVES: The aim of this study was to investigate the relationship between Bell's palsy and a novel oxidative stress parameter, thiol/disulphide homeostasis. DESIGN: A prospective study evaluating oxidative stress in Bell's palsy. SETTING: This research took place in the department of Otorhinolaryngology, Ataturk Training and Research Hospital. PARTICIPANTS: Totally, 77 patients with Bell's palsy and 38 healthy controls were included in this study. MAIN OUTCOME MEASURES: The blood levels of total and native thiol and disulphide activity were assessed, and their levels were compared in the patients and controls. RESULTS: There were statistically significant differences between the patients and controls regarding thiol/disulphide parameters. The mean native thiol and total thiol were significantly lower and disulphide levels were higher in the Bell's palsy than controls. On binary logistic regression analysis, the created model showed 45.3% variation. The cut-off value was 18.95 for disulphides. CONCLUSION: Native and total thiol levels were low in the Bell's palsy. This metabolic disturbance may have a role in the pathogenesis of Bell's palsy.

Residual Cervical Thymus: A Normal CT Finding That May Be Present Throughout Patients' Lives.

BACKGROUND AND PURPOSE: Although the thymus is centered in the mediastinum, often a cervical component can be seen in children and young adults. The frequency of radiologically evident residual cervical thymus in older adults is not known. The purpose of our study was to determine the proportion of adults who have residual cervical thymus visible on contrast-enhanced neck CT. MATERIALS AND METHODS: We retrospectively identified 700 patients who had undergone contrast-enhanced CT between February 2013 and August 2013. We categorized the patients by decade of life and calculated the proportion in which residual cervical thymic tissue could be detected. The location of the tissue focus, greatest axial diameter, and distance above the manubrium were recorded. A multivariate model was used to determine whether age or sex predicted the likelihood of identifiable cervical thymus, the size of residual thymus, or the distance of residual thymus above the sternum. RESULTS: Of the 700 patients, 157 (22.4%) had residual cervical thymus. The mean distance of the residual thymus above the manubrium was 13.4 ± 7.26 mm. The mean size of the residual cervical thymus was 12.5 ± 4.11 mm. The frequency of residual thymus decreased exponentially with age. There was a statistically significant relationship between age and the size of the residual cervical thymus (P = .02). Most of the cervical thymic tissue was found in the left paratracheal region. CONCLUSIONS: Residual cervical thymus may be present at any age, though the frequency decreases with increasing age.

Osteochondromas of the spine.

Osteochondromas are common developmental benign bone lesions, which rarely involve the spine. In a narrow space, such as the spinal canal, they may potentially lead to serious complications. Moreover, because this condition is fairly rare in the spine, it may be confused with other entities. The objective of this review is to describe the typical imaging findings of this rare, but occasionally significant condition of the spine.

Magnetic resonance imaging findings in chronic inflammatory demyelinating polyneuropathy with intracranial findings and enhancing, thickened cranial and spinal nerves.

Chronic inflammatory demyelinating polyneuropathy is a rare autoimmune disorder characterized by chronically progressive or relapsing symmetric sensorimotor involvement. We describe the imaging findings in our patient. Magnetic resonance imaging showed presence of an intracranial white matter lesion and enhancing, thickened cranial and spinal nerves. This disorder has been described very infrequently in the radiology literature.

Belowground bud banks and meristem limitation in tallgrass prairieplant populations.

Rhizome meristem populations were sampled in tallgrass prairie to quantify the size, grass : forb composition, and temporal and spatial variability of the soil bud bank and to compare fire effects on bud bank and seed bank composition. Soil cores (10.5 cm diameter, 15 cm deep) were collected from replicate annually and infrequently burned tallgrass prairie sites, and intact rhizomes and rhizome buds were censused. Bud bank densities ranged from approximately 600 to 1800 meristems/m(2) among sites and had high spatial and seasonal variability. In annually burned prairie, the total bud bank density was two-fold greater and the grass : forb meristem ratio was more than 30-fold greater than that of infrequently burned prairie. These patterns are opposite those observed in soil seed banks at this site. The rhizome population in annually burned prairie was 34% larger than the established aboveground tiller population. By contrast, the bud bank density in unburned prairie was significantly lower than aboveground stem densities, indicating possible belowground meristem limitation of stem density and net primary production on infrequently burned prairie. The patterns observed in this study suggest that the densities and dynamics of tallgrass prairie plant populations, as well as their response to disturbance (e.g., fire and grazing) and climatic variability, may be mediated principally through effects on the demography of belowground bud populations. Patterns of seed reproduction and seed bank populations have little influence on short-term aboveground population dynamics of tallgrass prairie perennials.

MRI in ankle tuberculosis: Review of 14 cases.

We reviewed the MR imaging features of ankle tuberculosis and determined the role of MR in its diagnosis. A retrospective analysis of 14 cases of ankle tuberculosis imaged with MRI was performed. Plain radiographs were also reviewed where available, and the imaging characteristics were noted. We also reviewed the medical records in order to assess the impact of the imaging findings on management of these patients. Magnetic resonance imaging is extremely helpful for detection, mapping the extent and resolution of the disease. It can identify cases, enables early institution of antituberculous chemotherapy and might obviate the need for surgery.

Mandibular haemophilic pseudotumour containing a fluid-fluid level.

Osseous haemophilic pseudotumours are uncommon. Mandibular haemophilic pseudotumours are rare, with only approximately 12 cases reported in the literature to date. We present imaging findings of a histopathologically proven mandibular haemophilic pseudotumour. A fluid-fluid level, hitherto not associated with this condition, is also described.

Unusual "floating balls" appearance of an ovarian cystic teratoma: sonographic and CT findings.

Ovarian cystic teratomas are cystic fatty tumors that can be easily diagnosed by sonography and CT. We present a case of ovarian cystic teratoma with an unusual sonographic appearance of mobile, hyperechoic, intracystic fat balls; this finding correlated well with the appearance on CT.

Imaging in isolated sacral tuberculosis: a review of 15 cases.

OBJECTIVE: To review imaging studies of isolated involvement of the sacrum due to tuberculosis and determine the role of imaging in the diagnosis and management of these patients. DESIGN AND PATIENTS: A retrospective analysis of 15 cases of isolated sacral tuberculosis imaged with MR imaging was performed. The CT images were also reviewed where available, and the various lesion characteristics were identified. We also reviewed the medical records in an attempt to determine the impact of the imaging studies on the management of these patients. RESULTS: Fifteen patients (5 male, 10 female) presented with symptoms of 3-15 months' duration. Chronic localized backache with muscle spasm was the commonest presenting symptom; discharging sinuses with abscess formation was found in six patients, five of whom were children. MR imaging of the sacrum revealed a hypointense marrow signal on T1-weighted images and hyperintense signal on T2-weighted images in 14 of 15 patients, the S2 vertebra being always involved. CT revealed osteolytic changes in the sacrum in all the five patients in whom CT was performed. All patients showed marked clinical improvement within 1 year of anti-tuberculous chemotherapy. CONCLUSION: Isolated tuberculosis of the sacrum is uncommon but should be suspected in patients presenting with chronic low backache or children with discharging sinuses/abscesses and showing sacral destruction on CT or MR imaging. MR imaging can identify cases and enables early institution of antituberculous chemotherapy.

Multiple intracranial lipomas, hypogenetic corpus callosum and vestibular schwannoma: an unusual spectrum of MR findings in a patient.

We describe imaging findings of a patient with multiple intracranial lipomas, hypogenetic corpus callosum and a vestibular schwannoma. We did not find association of intracranial lipomas and vestibular schwannoma in English literature.

Assessment of the genotoxic potential of riboflavin and lumiflavin. B. Effect of light.

On exposure to visible light, riboflavin and lumiflavin produced reactive oxygen species such as singlet oxygen and superoxide radicals. The reaction was found to be time- and concentration-dependent. Both riboflavin and lumiflavin, upon illumination, showed mutagenic response in the umu test as well as in the Ames/Salmonella assay with Salmonella typhimurium TA102. The mutagenic response was partially abolished by superoxide dismutase while sodium azide did not have any effect. No mutagenicity was observed if the compounds were not illuminated. The results suggested the involvement of superoxide radicals in light-induced mutagenicity of riboflavin as well as lumiflavin.

Assessment of the genotoxic potential of riboflavin and lumiflavin. A. Effect of metabolic enzymes.

The mutagenic potential of riboflavin and its photodegradation product lumiflavin was evaluated using the umu test, SOS chromotest and Ames Salmonella assay. Both riboflavin and lumiflavin by themselves were found to be non-mutagenic. On treatment with rat liver microsomal enzymes (S9) or caecal cell-free extract (CCE), lumiflavin acquired mutagenicity, while the status of riboflavin remained unaffected. Activation of lumiflavin by metabolic enzymes was found to result in an alteration of its spectral characteristics.

Cardiac dysautonomia in lepromatous leprosy.

Cardiovascular autonomic functions were studied in 32 patients of lepromatous leprosy, including 12 patients of lepra reaction. Fifty age and sex matched healthy subjects served as controls. Variable degree of autonomic dysfunction was observed in the study group. The derangement of autonomic functions in patients of leprosy can be explained on the basis of neurotrophic action of lepra bacilli that infiltrate the sympathetic and the parasympathetic fibres.