Structural and metabolic brain abnormalities in COVID-19 patients with sudden loss of smell.

OBJECTIVES: Sudden loss of smell is a very common symptom of coronavirus disease 19 (COVID-19). This study characterizes the structural and metabolic cerebral correlates of dysosmia in patients with COVID-19. METHODS: Structural brain magnetic resonance imaging (MRI) and positron emission tomography with [18F]-fluorodeoxyglucose (FDG-PET) were prospectively acquired simultaneously on a hybrid PET-MR in 12 patients (2 males, 10 females, mean age: 42.6 years, age range: 23-60 years) with sudden dysosmia and positive detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on nasopharyngeal swab specimens. FDG-PET data were analyzed using a voxel-based approach and compared with that of a group of healthy subjects. RESULTS: Bilateral blocking of the olfactory cleft was observed in six patients, while subtle olfactory bulb asymmetry was found in three patients. No MRI signal abnormality downstream of the olfactory tract was observed. Decrease or increase in glucose metabolism abnormalities was observed (p < .001 uncorrected, k ≥ 50 voxels) in core olfactory and high-order neocortical areas. A modulation of regional cerebral glucose metabolism by the severity and the duration of COVID-19-related dysosmia was disclosed using correlation analyses. CONCLUSIONS: This PET-MR study suggests that sudden loss of smell in COVID-19 is not related to central involvement due to SARS-CoV-2 neuroinvasiveness. Loss of smell is associated with subtle cerebral metabolic changes in core olfactory and high-order cortical areas likely related to combined processes of deafferentation and active functional reorganization secondary to the lack of olfactory stimulation.

Freehand stereotactic ventricular catheter insertion for ventriculoperitoneal shunts based on individualized radio-anatomical landmarks.

INTRODUCTION: The accurate placement of the ventricular catheter (VC) is critical in reducing the incidence of proximal failure of ventriculoperitoneal shunts (VPSs). The standard freehand technique is based on validated external anatomical landmarks but remains associated with a relatively high rate of VC malposition. Already proposed alternative methods have all their specific limitations. Herein, we evaluate the accuracy of our adapted freehand technique based on an individualized radio-anatomical approach. Reproducing the preoperative imaging on the patient's head using common anatomical landmarks allows to define stereotactic VC coordinates to be followed at surgery. MATERIAL AND METHODS: Fifty-five consecutive patients treated with 56 VPS between 11/2005 and 02/2020 fulfilled the inclusion criteria of this retrospective study. Burr hole coordinates, VC trajectory, and length were determined in all cases on preoperative computed tomography (CT) scan and were accurately reported on patients' head. The primary endpoint was to evaluate VC placement accuracy. The secondary endpoint was to evaluate the rate and nature of postoperative VC-related complications. RESULTS: Our new technique was applicable in all patients and no VC-related complications were observed. Postoperative imaging showed VC optimally placed in 85.7% and sub-optimally placed in 14.3% of cases. In all procedures, all the holes on the VC tip were found in the ventricular system. CONCLUSIONS: This simple individualized technique improves the freehand VC placement in VPS surgery, making its accuracy comparable to that of more sophisticated and expensive techniques. Further randomized controlled studies are required to compare our results with those of the other available techniques.

Fat emboli and critical illness-associated cerebral microbleeds (CICMs) in a patient with sickle cell disease: Do these 2 entities coexist?

We report the case of a 30-year-old female patient with sickle cell disease presenting with an acute chest syndrome and neurological deterioration. Cerebral magnetic resonance imaging revealed a handful of foci of diffusion restriction and numerous microbleeds with marked involvement of corpus callosum and subcortical white matter, with relative sparing of the cortex and deep white matter. Corpus callosum-predominant and juxtacortical microbleeds have been typically documented in cerebral fat embolism syndrome, but also in the so-called "critical-illness-associated cerebral microbleeds", a recently described entity associated with respiratory failure. We discussed whether these 2 entities may coexist.

Nonsyndromic bilateral and unilateral optic nerve aplasia: first familial occurrence and potential implication of CYP26A1 and CYP26C1 genes.

PURPOSE: Optic nerve aplasia (ONA, OMIM 165550) is a very rare unilateral or bilateral condition that leads to blindness in the affected eye, and is usually associated with other ocular abnormalities. Although bilateral ONA often occurs in association with severe congenital anomalies of the brain, nonsyndromic sporadic forms with bilateral ONA have been described. So far, no autosomal-dominant nonsyndromic ONA has been reported. The genetic basis of this condition remains largely unknown, as no developmental genes other than paired box gene 6 (PAX6) are known to be implicated in sporadic bilateral ONA. METHODS: The individuals reported underwent extensive ophthalmological, endocrinological, and neurologic evaluation, including neuroimaging of the visual pathways. In addition genomewide copy number screening was performed. RESULTS: Here we report an autosomal-dominant form of nonsyndromic ONA in a Belgian pedigree, with unilateral microphthalmia and ONA in the second generation (II:1), and bilateral ONA in two sibs of the third generation (III:1; III:2). No PAX6 mutation was found. Genome wide copy number screening revealed a microdeletion of maximal 363 kb of chromosome 10q23.33q23.33 in all affected individuals (II:1, III:1; III:2) and in unaffected I:1, containing three genes: exocyst complex component 6 (EXOC6), cytochrome p450, subfamily XXVIA, polypeptide 1 (CYP26A1), and cytochrome p450, subfamily XXVIC, polypeptide 1 (CYP26C1). The latter two encode retinoic acid-degrading enzymes. CONCLUSIONS: This is the first study reporting an autosomal-dominant form of nonsyndromic ONA. The diagnostic value of neuroimaging in uncovering ONA in microphthalmic patients is demonstrated. Although involvement of other genetic factors cannot be ruled out, our study might point to a role of CYP26A1 and CYP26C1 in the pathogenesis of nonsyndromic ONA.

A de novo SOX10 mutation causing severe type 4 Waardenburg syndrome without Hirschsprung disease.

Type 4 Waardenburg syndrome represents a well define entity caused by neural crest derivatives anomalies (melanocytes, intrinsic ganglion cells, central, autonomous and peripheral nervous systems) leading, with variable expressivity, to pigmentary anomalies, deafness, mental retardation, peripheral neuropathy, and Hirschsprung disease. Autosomal dominant mode of inheritance is prevalent when Sox10 gene mutation is identified. We report the natural history of a child who presented with synophrys, vivid blue eye, deafness, bilateral complete semicircular canals agenesis with mental retardation, subtle signs for peripheral neuropathy and lack of Hirschsprung disease. SOX10 gene sequencing identified "de novo" splice site mutation (c.698-2A > C). The present phenotype and the genotype findings underline the wide spectrum of SOX10 gene implication in unusual type 4 Waardenburg syndrome patient.

Irradiation of cochlear structures during vestibular schwannoma radiosurgery and associated hearing outcome.

OBJECT: The purpose of this study was to measure the dose of radiation delivered to the cochlea during a Gamma knife surgery (GKS) procedure for treatment of patients with vestibular schwannomas (VSs), and to analyze the relationship between cochlear irradiation and the hearing outcome of these patients. METHODS: Eighty-two patients with VSs were treated with GKS using a marginal dose of 12 Gy. No patient had neurofibromatosis Type 2 disease, and all had a Gardner-Robertson hearing class of I to IV before treatment, and a radiological and audiological follow-up of at least 1-year after GKS. The dosimetric data of the volume of the cochlea were retrospectively analyzed and were correlated with the auditory outcome of patients. RESULTS: The mean radiation dose delivered to the cochlear volume ranged from 1.30 to 10.00 Gy (median 4.15 Gy). The cochlea received significantly higher radiation doses in patients with worsening of hearing after GKS. A highly significant association between the cochlear and the intracanalicular dose of radiation delivered during GKS was found. CONCLUSIONS: During GKS for VSs, relatively high doses of radiation can be delivered to the cochlea. Worsening of hearing after GKS can be the consequence of either radiation injury to the cochlea or the irradiation dose delivered into the auditory canal, or both.

Comprehensive management of congenital choanal atresia.

OBJECTIVES: To present results of a one-stage minimally invasive surgical procedure for congenital choanal atresia (CCA). Seven outcome measures were applied. MATERIALS AND METHODS: Retrospective study conducted between 1999 and 2015. The same endonasal endoscopic approach with multiflaps and no stenting was used on 36 children. The flaps were attached with fibrine glue. There were 50% unilateral and 50% bilateral cases, 70% primary and 30% secondary surgery. The mean age at primary surgery for bilateral atresia was 10 days and for unilateral atresia 4 years. Associated loco-regional disorders were: hypoplasia of the inferior turbinate, rhinopharyngeal stenosis and rhinopharyngeal web. RESULTS: The average follow-up time was 6 years, ranging from 1 to 14 years. There was a functionally patent choanae in 94% of children, and 6% showed severe restenosis with a diameter less than 4 mm, which needed one revision surgery each. Charge patients were not associated with worse outcome. There was no external nasal valve stenosis and no permanent Eustachian tube dysfunction. Synechiae occurred in 3 patients with hyperplastic inferior turbinate. No patients showed any disharmonious nasal growth. In neonates with isolated bilateral CCA, breast-suction could be started within 1 day (range 1-2 days), and pain-killers were needed on average for 1.5 days (range 1-4 days). The hospital stay for unilateral isolated CCA was on average 1.5 days (range 1-2 days) and for bilateral isolated CCA, 8 days (range 3-20 days). Postoperative procedures under a short general anesthesia were necessary in 12 cases, 10 of them were infants under 6 months of age. CONCLUSION: Surgery could be performed safely in the newborn in the early stage of life, even for unilateral atresia. Tendency for restenosis can be minimized by: 1. the construction of an as large as possible uni-neochoanae by removing the posterior part of the vomer and by drilling away the medial pterygoid; 2. in case of rhinopharyngeal stenosis, part of the endochondral clivus bone should be resected; 3. all raw surfaces should be covered by multiple mucosal flaps secured with fibrin glue; 4. no stenting; 5. appropriate postoperative care.

MDCT imaging of traumatic brain injury.

The aim of emergency imaging is to detect treatable lesions before secondary neurological damage occurs. CT plays a primary role in the acute setting of head trauma, allowing accurate detection of lesions requiring immediate neurosurgical treatment. CT is also accurate in detecting secondary injuries and is therefore essential in follow-up. This review discusses the main characteristics of primary and secondary brain injuries.

A case of lipoma arising in the eustachian tube.

We report a case of a lipoma inside the eustachian tube, an extremely rare location for this lesion. To the best of our knowledge, this is only the second such case that has been described in the literature. The patient was a 47-year-old man, a fighter pilot, who was referred to our hospital with a 3-year history of (1) fullness in the right ear secondary to recurrent serous otitis media and (2) right ear pain, which was especially acute during flights. Nasopharyngeal endoscopy, computed tomography, and magnetic resonance imaging detected the presence of a well-encapsulated lesion inside the eustachian tube; macroscopic and radiologic findings identified the mass as a lipoma. The lesion was completely removed via transnasal endoscopy. Histopathologic evaluation confirmed the diagnosis of lipoma. The patient's postoperative course was favorable, and he was able to fly again without any ear complaints. Radiologic examination is useful for the diagnosis and preoperative evaluation of this benign tumor. Lesions located in the lower part of the eustachian tube can be easily removed via a transnasal endoscopic approach.

Bony Regeneration of the Sella after Transsphenoidal Pituitary Surgery.

OBJECTIVE: The purpose of this study is to demonstrate the possible bony regrowth of the sella after transsphenoidal surgery without any intraoperative sellar reconstruction. METHODS: Radiologic findings of the sella were reviewed in patients with pituitary tumors treated by transsphenoidal surgery. In 17 patients who had postoperative cranial computed tomography scans, bony regeneration of the sellar floor was evaluated by comparing immediate and late postoperative scans. The bony opening reduction was measured in transverse and sagittal planes. RESULTS: The median bony opening diameter in the transverse plane was 8.8 mm (interquartile range [IQR] 5.7-11.4) on the first scan and 4.2 mm (IQR 0.8-6.8) on the second scan. In the sagittal plane, it was 4.8 mm (IQR 1.8-6.8) on the first scan and 2.9 mm (IQR 1.6-3.9) on the second scan. These changes occurred in a median time of 36 months (IQR 22-42). There was a statistically significant decrease of the bony opening diameters in both the transverse and sagittal planes (P < 0.0001 and P = 0.0004, respectively). Bone regeneration was observed in 16 of the 17 patients (approximately 94%). CONCLUSION: There is a natural bony regeneration of the sella after transsphenoidal pituitary surgery.

Posterior osteosynthesis of the atlas for nonconsolidated Jefferson fractures: a new surgical technique.

STUDY DESIGN: Case report and surgical technique. OBJECTIVE: To describe a new technique to treat atlas burst fractures by selectively reconstructing the atlas from a posterior approach. SUMMARY OF BACKGROUND DATA: The two surgical techniques reported until now for stabilizing atlas burst fractures are associated with some drawbacks. Posterior C0-C2 or C1-C2 fixations significantly reduce head rotation, while the transoral C1 lateral masses osteosynthesis can be associated with oropharyngeal and neurological complications. We propose a new surgical technique for the treatment of unstable Jefferson fractures aimed at avoiding these problems. METHODS: A 25-year-old man presented with a Jefferson type III atlas fracture after a traffic accident. The fracture failed to consolidate after 3 months of halo brace immobilization. Surgery consisted in inserting bilateral posterior C1 lateral mass screws interconnected by a transversal rod, thereby creating a second C1 posterior arch under the fractured one. RESULTS: Postoperative course was uneventful. Immediate postoperative stability was confirmed on dynamic X-ray films and head rotation was preserved. Delayed computed tomography scan demonstrated fracture consolidation. CONCLUSION: The surgical technique described is new and effective for treating atlas burst fractures. This posterior procedure allows mobility preservation, with a low morbidity rate.

¹8F-FDG PET/CT and MRI in the follow-up of head and neck squamous cell carcinoma.

We evaluated the diagnostic performance of (18)F-FDG PET/CT and MRI for the assessment of head and neck squamous cell carcinoma (HNSCC) relapse. Since early treatment might prevent inoperable relapse, we also evaluated THE performance of early unenhanced (18)F-FDG PET/CT in residual tumor detection. The study was prospectively performed on 32 patients who underwent (18)F-FDG PET/CT and MRI before treatment and at 4 and 12 months after treatment. (18)F-FDG PET/CT was also performed 2 weeks after the end of radiotherapy. Histopathology or a minimum of 18 months follow-up were used as gold standard. Before treatment (18)F-FDG PET/CT and MRI detected all primary tumors except for two limited vocal fold lesions (sensitivity 94%). MRI was more sensitive than (18)F-FDG PET/CT for the detection of local extension sites (sensitivity 75 vs 58%), but at the cost of a higher rate of false positive results (positive predictive value 74 vs 86%). For relapse detection at 4 months, sensitivity was significantly higher for (18)F-FDG PET/CT (92%) than for MRI (70%), but the diagnostic performances were not significantly different at 12 months. For the detection of residual malignant tissue 2 weeks post-radiotherapy, sensitivity and specificity of (18)F-FDG PET/CT were respectively 86 and 85% (SUV cut-off value 5.8). (18)F-FDG PET/CT is effective in the differentiation between residual tumor and radiation-induced changes, as early as 2 weeks after treatment of a primary HNSCC. For follow-up, performance of (18)F-FDG PET/CT and MRI are similar except for a higher sensitivity of (18)F-FDG PET/CT at 4 months.

Ultrasound-guided fine-needle aspiration of thyroid nodules: stratification of malignancy risk using follicular proliferation grading, clinical and ultrasonographic features.

OBJECTIVE: To evaluate the diagnostic value of fine-needle aspiration (FNA) cytology and the additive contribution brought by clinical and ultrasound (US) features. METHOD: Cytological and histological diagnoses were compared in a series of 924 patients who underwent US-guided FNA before surgery. We additionally developed a grading system for follicular proliferation (FP) FNA diagnosis, and investigated its impact on the malignancy risk as well as the additive contribution of clinical and US features by means of decision tree analysis. RESULTS: Excluding FP cases (n=395), our data demonstrated that strictly benign or malignant FNA diagnoses exhibit great concordance with benign or malignant histological diagnoses (97.8% accuracy). Our grading system that was applied to the 395 FP cases revealed that grades 1, 2 and 3 were associated with a 7.7, 17.7 and 45.7% incidence of malignancy respectively. Decision tree analysis resulted in a classification model which involved FP grade, patient's age, serum thyroglobulin level, nodule size and nodule uniqueness. This model identified a subgroup of patients with grade 1 FP nodules who were older than 50 years, and who had a higher risk of malignancy (17.9%). In addition, high serum thyroglobulin levels were associated with a very high malignancy risk (75.0%) for patients with grade 3 FP nodules. Finally, among grade 2 FP patients, unique and large nodules were associated with a high malignancy risk of 36.1%. CONCLUSIONS: The integration of FP grade, clinical and US features allows the stratification of patients with FP cytology according to their risk of malignancy.

Accurate pre-operative localization of pathological parathyroid glands using 11C-methionine PET/CT.

OBJECTIVE: The pre-operative technique most routinely used to localize pathological parathyroid glands (PPG), prior to minimal access surgery (MAS), relies on 99mTc-sestamibi (MIBI) scintigraphy. Positron emission tomography (PET) using the radiolabelled amino acid 11C-methionine as the tracer agent offers a technological alternative to localize PPG. In this study we evaluated the sensitivity of 11C-methionine PET/CT (MET-PET/CT) for PPG detection and the extent to which MET-PET/CT images may contribute to the planning of surgical procedures. DESIGN: Thirty patients were included, 22 with primary hyperparathyroidism and eight with secondary hyperparathyroidism. Patients suspected of suffering from parathyroid hyperplasia underwent a complete surgical exploration of the neck region. In those suspected of parathyroid adenoma, surgery was limited to the presumed localization described by MET-PET/CT. To specifically address the additional benefit of the MET-PET/CT in terms of surgical planning and procedure, the surgeon classified the patients into two categories depending on the type of benefit, or the reason for the absence of benefit, occurring in each case. We also compared the sensitivity of MET-PET/CT and MIBI scintigraphy. RESULTS: The total number of lesions removed was 46 (24 adenomatous and 22 hyperplastic). Globally, MET-PET/CT provided additional benefit to surgery in 15 out of 30 cases (50%). The sensitivity of 11C-methionine PET/CT and MIBI scintigraphy was respectively 92% and 95% for adenoma, and 68% and 59% for hyperplasia, on the basis of available resected lesions. CONCLUSION: MET-PET/CT appears a reliable technique to guide MAS of parathyroid glands.

Complications of lumbar puncture in a child treated for leukaemia.

Lumbar puncture may lead to neurological complications. These include intracranial hypotension, cervical epidural haematomas, and cranial and lumbar subdural haematomas. MRI is the modality of choice to diagnose these complications. This report documents MRI findings of such complications in a child treated for leukaemia.

Low-dose unenhanced multidetector CT of patients with suspected renal colic.

OBJECTIVE: This study is designed to assess the intraobserver and interobserver agreements and the diagnostic performances of low-dose unenhanced multidetector CT (MDCT) in patients with suspected renal colic. SUBJECTS AND METHODS: The study included 106 patients who underwent unenhanced MDCT with 4 x 2.5 mm collimation, 120 kVp, 30 mAs, and, if necessary, additional focused acquisitions at 60 or 120 mAs on areas with an equivocal ureteral stone or with significant image noise. The effective radiation dose was computer-simulated with software based on the Monte Carlo model and International Commission on Radiological Protection recommendations. CT scans were archived and independently reviewed by three radiologists during two interpretation sessions on a workstation with three dimensions functions. Intraobserver and interobserver agreements were calculated with the kappa statistics. Accuracy for detection of ureteral stone on low-dose MDCT was calculated by comparison with combined clinical (stone passage), surgical (stone retrieval, extracorporeal shock wave lithotripsy), biologic (urinalysis, urine culture), and other imaging (excretory urography, standard-dose MDCT, follow-up sonography, and abdominal radiography) findings or by evidence for an alternative diagnosis. RESULTS: Ureteral stones were present in 38 (36%) of 106 patients. Thirty-six of 38 ureteral stones were detected by low-dose MDCT. From reviewer to reviewer, the number of true-positive, false-positive, true-negative, and false-negative findings ranged, respectively, from 34 to 36, 1 to 4, 64 to 68, and 2 to 4. The corresponding sensitivity, specificity, and accuracy ranged from 89.5% to 94.7%, from 94.1% to 100%, and from 93.4% to 98.1%, respectively. The intraobserver and interobserver agreements were excellent, with kappa values ranging from 0.87 to 0.98. In 13 patients, an alternative diagnosis explaining the patient's symptoms was proposed by all reviewers using images obtained at 30 mAs. No additional or alternative diagnosis was found at standard dose. At 30 mAs, the mean effective dose was 1.2 mSv in men and 1.9 mSv in women. Additional acquisitions at 60 mAs, all focused on the lower pelvis, were acquired in 20 patients, but the corresponding images were needed by the reviewers for only six of them. The acquisitions at 60 mAs were responsible for an additional mean effective dose of 0.5 in men and 0.8 mSv in women. CONCLUSION: Our study shows that low-dose unenhanced MDCT is appropriate for the diagnosis of ureteral stones, and that it provides excellent intraobserver and interobserver agreements and does not obscure alternative diagnoses.