MRI Safety of Stapes Prostheses: A Systematic Review.

OBJECTIVE: To assess magnetic resonance imaging (MRI) safety of stapes prostheses. DATA SOURCES: Ovid MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Web of Science, and Scopus databases were searched from inception to November 2021 following PRISMA guidelines. REVIEW METHODS: Studies reporting evidence of stapes prosthesis displacement or interaction in adult or pediatric implant recipients undergoing MRI. Cadaveric, animal, and basic studies with nonhuman data were also included. RESULTS: From an initial search of 123 articles, 42 full-text studies were evaluated for eligibility and 19 studies that met the inclusion criteria were included. Motion artifact was reported in a few stainless steel prosthesis types in vitro; however, such displacement was not observed in human cadaver temporal bone studies and had no adverse reported outcomes. A small subgroup of patients in the 1980s received a ferromagnetic stainless steel stapes implant that was recalled and has not been used since 1987. Patients with implants performed in the 1980s should be directed to 1.5T scanners from an abundance of caution. CONCLUSION: Modern (post-1987) stapes prostheses do not pose a risk in vivo when exposed to the magnetic fields of MRI scanners.

Spinal Cerebrospinal Fluid Leak Localization with Dynamic Computed Tomography Myelography: Tips, Tricks, and Pitfalls.

Locating spinal cerebrospinal fluid (CSF) leaks can be a diagnostic dilemma for clinicians and radiologists, as well as frustrating for patients. Dynamic computed tomography myelography (dCTM) has emerged as a valuable tool in localizing spinal CSF leaks, aiding in accurate diagnosis, and guiding appropriate management. This article aims to provide insights into the technique, tips, tricks, and potential pitfalls associated with dCTM for spinal CSF leak localization. By understanding the nuances of this procedure, clinicians can optimize the diagnostic process and improve patient outcomes.

Temporal Characteristics of CSF-Venous Fistulas on Dynamic Decubitus CT Myelography: A Retrospective Multi-Institution Cohort Study.

BACKGROUND AND PURPOSE: CSF-venous fistula can be diagnosed with dynamic decubitus CT myelography. This study aimed to analyze the temporal characteristics of CSF-venous fistula visualization on multiphase decubitus CT myelography. MATERIALS AND METHODS: A retrospective, multisite study was conducted on patients diagnosed with CSF-venous fistula at 2 institutions between June 2017 and February 2023. Both institutions perform decubitus CT myelography with imaging immediately following injection and usually with at least 1 delayed scan. The conspicuity of CSF-venous fistula was assessed on each phase of imaging. RESULTS: Forty-eight patients with CSF-venous fistula were analyzed. CSF-venous fistulas were better visualized on the early pass in 25/48 cases (52.1%), the delayed pass in 6/48 cases (12.5%) and were seen equally on both passes in 15/48 cases (31.3%). Of 25 cases in which the CSF-venous fistula was better visualized on the early pass, 21/25 (84%) fistulas were still at least partially visible on a delayed pass. Of 6 cases in which the CSF-venous fistula was better visualized on a delayed pass, 4/6 (67%) were partially visible on the earlier pass. Six of 48 (12.5%) CSF-venous fistulas were visible only on a single pass. Of these, 4/6 (66.7%) were seen only on the first pass, and 2/6 (33.3%) were seen only on a delayed pass. One fistula was found with one pass only, and one fistula was discovered upon contralateral decubitus imaging without a dedicated second injection. CONCLUSIONS: A dynamic decubitus CT myelography imaging protocol that includes an early and delayed phase, likely increases the sensitivity for CSF-venous fistula detection. Further studies are needed to ascertain the optimal timing and technique for CSF-venous fistula visualization on dynamic decubitus CT myelography and its impact on patient outcomes.

Unusual neuroimaging findings in spontaneous intracranial hypotension.

PURPOSE: The most common neuroimaging manifestations of patients suffering from spontaneous intracranial hypotension (SIH) include subdural fluid collections, enhancement of the pachymeninges, engorgement of venous structures, pituitary hyperemia, sagging of the brainstem, and cerebellar hemosiderosis. However, infrequently patients may present with separate neuroradiological findings which could be easily mistaken for other pathology. METHODS: We describe patients who presented with unique neuroimaging findings who were eventually found to have a spinal CSF leak or venous fistula. Relevant clinical history and neuroradiology findings are presented, and a relevant review of the literature is provided. RESULTS: We present six patients with a proven CSF leak or fistula who presented with dural venous sinus thrombosis, compressive ischemic injury, spinal hemosiderosis, subarachnoid hemorrhage, pial vascular engorgement, calvarial hyperostosis, and spinal dural calcifications. CONCLUSION: Radiologists should be familiar with atypical neuroimaging manifestations of SIH in order to avoid misdiagnosis and guide the clinical trajectory of the patient towards accurate diagnosis and eventual cure.

Utility of microbiologic testing in surveillance bronchoscopy following lung transplantation: A retrospective cohort study.

BACKGROUND: The utility of surveillance bronchoscopy (SB) for the clinical management of lung transplant recipients (LTRs) is undefined. This study evaluates the role of SB in the monitoring and care of LTRs. METHODS: We retrospectively analyzed all LTRs who had SB at Henry Ford Hospital in Detroit, Michigan between August 2014 and August 2019. Bronchoscopies performed for clinical symptoms, new radiographic abnormalities, and to assess stents or acute rejection were excluded. A total of 107 LTRs and 449 bronchoscopies were analyzed. The primary outcome was the rate of change in clinical care based on microbiologic and pathologic test results. Secondary outcomes were rates of microbiologic and pathologic test positivity and rates of adverse effects. RESULTS: The most common microbiologic tests performed on bronchoalveolar lavage were bacterial (96.9%), fungal (95.3%), and acid-fast bacillus (95.1%) stains and cultures. Of 2560 microbiologic tests, 22.0% were positive and resulted in therapy changes for 2.9%. Positive galactomannan, acid-fast bacillus tests, and Pneumocystis jirovecii antigen/polymerase chain reaction did not result in therapy changes. Of the 370 transbronchial biopsies performed, 82.2% were negative for acute rejection and 13% were positive for A1/A2 rejection. Immunosuppressive therapy changes occurred after 15.8% with reduction in immunosuppression due to positive microbiologic tests in 16.9%. Adverse events occurred in 8.0% of patients. CONCLUSION: Diagnostic stewardship is warranted when performing SB in LTRs.

Magnetic Resonance Imaging Prognostic Findings for Visual and Mortality Outcomes in Acute Invasive Fungal Rhinosinusitis.

PURPOSE: To identify initial, preintervention magnetic resonance imaging (MRI) findings that are predictive of visual and mortality outcomes in acute invasive fungal rhinosinusitis (AIFRS). DESIGN: Retrospective cohort study. PARTICIPANTS: Patients with histopathologically or microbiologically confirmed AIFRS cared for at a single, tertiary academic institution between January 2000 and February 2020. METHODS: A retrospective review of MRI scans and clinical records of patients with confirmed diagnosis of AIFRS was performed. For each radiologic characteristic, a modified Poisson regression with robust standard errors was used to estimate the risk ratio for blindness. A multivariate Cox proportional hazards model was used to study AIFRS-specific risk factors associated with mortality. MAIN OUTCOME MEASURE: Identification of initial, preintervention MRI findings associated with visual and mortality outcomes. RESULTS: The study comprised 78 patients (93 orbits, 63 with unilateral disease and 15 with bilateral disease) with AIFRS. The leading causes of immunosuppression were hematologic malignancy (38%) and diabetes mellitus (36%). Mucormycota constituted 56% of infections, and Ascomycota constituted 37%. The overall death rate resulting from infection was 38%. Risk factors for poor visual acuity outcomes on initial MRI included involvement of the orbital apex (relative risk [RR], 2.0; 95% confidence interval [CI], 1.1-3.8; P = 0.026) and cerebral arteries (RR, 1.8; 95% CI, 1.3-2.5; P < 0.001). Increased mortality was associated with involvement of the facial soft tissues (hazard ratio [HR], 4.9; 95% CI, 1.3-18.2; P = 0.017), nasolacrimal drainage apparatus (HR, 5.0; 95% CI, 1.5-16.1; P = 0.008), and intracranial space (HR, 3.5; 95% CI, 1.4-8.6; P = 0.006). Orbital soft tissue involvement was associated with decreased mortality (HR, 0.3; 95% CI, 0.1-0.6; P = 0.001). CONCLUSIONS: Extrasinonasal involvement in AIFRS typically signals advanced infection with the facial soft tissues most commonly affected. The initial, preintervention MRI is prognostic for a poor visual acuity outcome when orbital apex or cerebral arterial involvement, or both, are present. Facial soft tissues, nasolacrimal drainage apparatus, intracranial involvement, or a combination thereof is associated with increased mortality risk, whereas orbital soft tissue involvement is correlated with a reduced risk of mortality.

COVID-19 Radiology Preparedness, Challenges & Opportunities: Responses From 18 Countries.

PURPOSE: Radiology departments around the world have been faced with the challenge to adapt, and recover to the COVID-19 pandemic. This study is part of a worldwide survey of radiologists' responses to COVID-19 in 18 different countries in Africa, Asia, Europe, and Latin America. The purpose of this study is to analyze the changes made in international radiology departments and practices in response to the pandemic. METHODS: The 18-item survey was sent via email from April to May 2020 to radiologists in Africa, Asia, Europe, and Latin America to assess their response to COVID-19. Our survey included questions regarding imaging, workforce adjustments, testing availability, staff and patient safety, research and education, and infrastructure availability. RESULTS: Twenty-eight survey responses were reviewed. Of the 28 respondents, 42.9% have shortages of infrastructure and 78.6% responded that COVID-19 testing was available. Regarding the use of Chest CT in COVID-19 patients, 28.6% respondents used Chest CT as screening for COVID-19. For staff safety, interventions included encouraging use of masks in patient encounters, social distancing and PPE training. To cope with their education and research mission, radiology departments are doing online lectures, reducing the number of residents in rotations, and postponing any non-urgent activities. CONCLUSION: In conclusion, there are disparities in infrastructure, research, and educational initiatives during COVID-19 which also provides opportunity for the global radiology community to work together on these issues.

50th anniversary of computed tomography: past and future applications in clinical neuroscience.

Purpose: It has been 50 years since computed tomography was introduced to the worldwide neurologic medical and surgical community. In that time, tremendous advances in computer software and hardware, as well as creative changes in computerized tomographic (CT) hardware and tube technology, have dramatically improved the temporal and spatial resolution of CT. In this paper, I address what I feel are some of the most important impacts of CT in the field of clinical neuroscience over the last 50 years, as well as potential applications of CT that are on the horizon. Approach: I have recounted from literature, colleagues, and personal recollection the historical impact of CT on neuroradiology practice and what appear to be near-term future applications. Conclusions: Therapeutic applications beyond diagnosis, such as image-guided procedures, radiation, and surgical planning, and development of the field of theranostics have emerged and further increased the need for faster and more precise CT imaging. The integration of machine learning into the acquisition chain and radiologist tool kit has great implications for standardization, analysis, and diagnosis worldwide.

Cerebrospinal fluid-lymphatic fistula causing spontaneous intracranial hypotension in a child with kaposiform lymphangiomatosis.

Spontaneous intracranial hypotension is an uncommon etiology of secondary headaches in children. We report a unique case of a girl with kaposiform lymphangiomatosis who developed postural headaches and imaging features of spontaneous intracranial hypotension without a spinal extradural collection. The girl underwent dynamic computed tomography myelography which revealed a cerebrospinal fluid (CSF)-lymphatic fistula related to a lymphatic malformation associated with the right T10 nerve. She underwent surgical ligation of the CSF-lymphatic fistula, resulting in resolution of the headaches. Spinal CSF-lymphatic fistulas are rare and have previously been reported in two patients with Gorham-Stout disease. The current report suggests that patients with systemic lymphatic anomalies who develop postural headaches should undergo evaluation for spontaneous intracranial hypotension and a CSF-lymphatic fistula. If discovered, surgical ligation is a potential treatment.

Metabolic remodeling precedes mTORC1-mediated cardiac hypertrophy.

RATIONALE: The nutrient sensing mechanistic target of rapamycin complex 1 (mTORC1) and its primary inhibitor, tuberin (TSC2), are cues for the development of cardiac hypertrophy. The phenotype of mTORC1 induced hypertrophy is unknown. OBJECTIVE: To examine the impact of sustained mTORC1 activation on metabolism, function, and structure of the adult heart. METHODS AND RESULTS: We developed a mouse model of inducible, cardiac-specific sustained mTORC1 activation (mTORC1iSA) through deletion of Tsc2. Prior to hypertrophy, rates of glucose uptake and oxidation, as well as protein and enzymatic activity of glucose 6-phosphate isomerase (GPI) were decreased, while intracellular levels of glucose 6-phosphate (G6P) were increased. Subsequently, hypertrophy developed. Transcript levels of the fetal gene program and pathways of exercise-induced hypertrophy increased, while hypertrophy did not progress to heart failure. We therefore examined the hearts of wild-type mice subjected to voluntary physical activity and observed early changes in GPI, followed by hypertrophy. Rapamycin prevented these changes in both models. CONCLUSION: Activation of mTORC1 in the adult heart triggers the development of a non-specific form of hypertrophy which is preceded by changes in cardiac glucose metabolism.

CT-guided Fibrin Glue Occlusion of Cerebrospinal Fluid-Venous Fistulas.

Background Cerebrospinal fluid-venous fistulas (CVFs) are one of the less common etiologic causes of spontaneous intracranial hypotension. CVFs are most commonly treated with open surgical ligation and have reportedly not responded well to percutaneous treatments. Purpose To study treatment outcomes of CT-guided fibrin glue occlusion for CVFs. Materials and Methods Retrospective review of medical records from two institutions was performed for all patients with CVFs who underwent CT-guided percutaneous fibrin glue occlusion from March to October 2020. CVFs were assessed for resolution or persistence at posttreatment decubitus CT myelography (CTM). Pre- and posttreatment brain MRI scans were reviewed for principal signs of spontaneous intracranial hypotension. Clinical symptoms were documented before and immediately after therapy, and the current symptoms to date after fibrin glue occlusion were documented. Results CT-guided fibrin glue occlusion was performed in 13 patients (mean age, 62 years ± 14 [standard deviation]; eight women) with CVFs. Ten of 10 patients who underwent final posttreatment decubitus CTM examinations showed CVF resolution. All 13 patients showed improvement on posttreatment brain MRI scans. All 13 patients are currently asymptomatic, although three patients were asymptomatic before fibrin glue occlusion. Conclusion CT-guided fibrin glue occlusion is an effective treatment for patients with cerebrospinal fluid-venous fistulas (CVFs). Direct fibrin glue administration within the CVF may be one of the key factors for success. Further studies are needed to determine the long-term efficacy of this treatment. © RSNA, 2021.

Cerebrospinal Fluid-Venous Fistulas: A Systematic Review and Examination of Individual Patient Data.

BACKGROUND: Spontaneous intracranial hypotension (SIH) is usually caused by a spinal cerebrospinal fluid (CSF) leak. CSF-venous fistula is an underdiagnosed cause of spinal CSF leak, as it is challenging to identify on myelography. OBJECTIVE: To review existing literature to summarize common presentations, diagnostic imaging modalities, and current treatment strategies for CSF-venous fistulas. METHODS: We conducted a systematic review using PubMed, Embase, Scopus, and Web of Science databases to identify studies discussing CSF-venous fistulas. Titles and abstracts were screened. Studies meeting prespecified inclusion criteria were reviewed in full. RESULTS: Of 180 articles identified, 16 articles met inclusion criteria. Individual patient data was acquired from 7 studies reporting on 18 patients. CSF-venous fistula most frequently presented as positional headache. Digital subtraction myelography provided greatest detection of CSF-venous fistula in the lateral decubitus position and detected CSF-venous fistula in all individual patient cases. Dynamic computed tomography (CT) myelogram enabled detection and differentiation of CSF-venous fistulas from low-flow epidural leaks. The majority of fistulas were in the thoracic spine and slightly more common on the right. Epidural blood patch (EBP) provided temporary or no relief in all individual patients. Resolution or improvement of clinical symptoms and radiologic normalization were observed in all surgically treated patients. CONCLUSION: Although rare, CSF-venous fistula is an important cause of spinal CSF leak contributing to SIH. Dynamic CT myelogram and digital subtraction myelography, particularly in the lateral decubitus position, are the most accurate and effective diagnostic imaging modalities. EBPs often provide only transient relief, while surgical management is preferred.

Bilateral superior ophthalmic vein thrombosis associated with high altitude.

We report a case of a 47-year-old female who experienced periorbital swelling while descending from a Himalayan mountain climb and was found to have bilateral superior ophthalmic vein thromboses (SOVT). Infectious, autoimmune, and hypercoagulability work-up were negative with no cavernous sinus involvement. Symptoms resolved upon initiation of anticoagulation and oral steroids. SOVT is a rare but serious condition and has a risk of extending into the cavernous sinus if not treated early. Although infection is the most common etiology, venous thrombosis can be precipitated under high altitude and low oxygen pressure environments. We present a case of superior ophthalmic vein thrombosis associated with high-altitude conditions.

Venous sinus stenting as a treatment approach in patients with idiopathic intracranial hypertension and encephaloceles.

BACKGROUND: Stenosis of a dural venous sinus is the most common cause of idiopathic intracranial hypertension (IIH) and can be classified as either intrinsic or extrinsic. Intrinsic stenoses are characterized by a focal filling defect within the sinus secondary to an enlarged arachnoid granulation or fibrous septa while extrinsic stenoses tend to be long and smooth-tapered and are most commonly secondary to external compression from the adjacent brain parenchyma. Brain herniations, or encephaloceles, into arachnoid granulations in dural venous sinuses have rarely been reported in the literature in patients with IIH. We propose that dural venous sinus stenting (VSS) may be a safe and effective treatment approach in patients with an encephalocele and IIH. METHODS: We retrospectively analyze three cases of patients with encephalocele who underwent VSS for treatment of medically refractory IIH at our institution. RESULTS: One patient underwent stenting ipsilateral and two patients underwent stenting contralateral to the side of their encephaloceles. No technical related issues or complications occurred during either of the three stenting procedures. Two out of the three patients had complete resolution in their IIH-related symptoms and normalization of cerebrospinal (CSF) pressures shortly after stenting. We await clinical follow-up in the third patient. CONCLUSIONS: Our results suggest that VSS is a technically feasible and effective approach in treating patients with medically refractory IIH and encephaloceles.

Quantitative [18F]-Naf-PET-MRI Analysis for the Evaluation of Dynamic Bone Turnover in a Patient with Facetogenic Low Back Pain.

Imaging techniques that reflect dynamic bone turnover may aid in characterizing a wide range of bone pathologies. Bone is a dynamic tissue undergoing continuous remodeling with the competing activity of osteoblasts, which produce the new bone matrix, and osteoclasts, whose function is to eliminate mineralized bone. [18F]-NaF is a positron emission tomography (PET) radiotracer that enables visualization of bone metabolism. [18F]-NaF is chemically absorbed into hydroxyapatite in the bone matrix by osteoblasts and can thus noninvasively detect osteoblastic activity, which is occult to conventional imaging techniques. Kinetic modeling of dynamic [18F]-NaF-PET data provides detailed quantitative measures of bone metabolism. Conventional semi-quantitative PET data, which utilizes standardized uptake values (SUVs) as a measure of radiotracer activity, is referred to as a static technique due to its snapshot of tracer uptake in time.  Kinetic modeling, however, utilizes dynamic image data where tracer levels are continuously acquired providing tracer uptake temporal resolution. From the kinetic modeling of dynamic data, quantitative values like blood flow and metabolic rate (i.e., potentially informative metrics of tracer dynamics) can be extracted, all with respect to the measured activity in the image data. When combined with dual modality PET-MRI, region-specific kinetic data can be correlated with anatomically registered high-resolution structural and pathologic information afforded by MRI. The goal of this methodological manuscript is to outline detailed techniques for performing and analyzing dynamic [18F]-NaF-PET-MRI data. The lumbar facet joint is a common site of degenerative arthritis disease and a common cause for axial low back pain.  Recent studies suggest [18F]-NaF-PET may serve as a useful biomarker of painful facetogenic disease.  The human lumbar facet joint will, therefore, be used as a prototypical region of interest for dynamic [18F]-NaF-PET-MRI analysis in this manuscript.

Ectopic Thyroid-Stimulating Hormone-Secreting Pituitary Adenoma of the Nasopharynx Diagnosed by Gallium 68 DOTATATE Positron Emission Tomography/Computed Tomography.

BACKGROUND: Ectopic thyroid-secreting hormone (TSH)-secreting pituitary adenomas are rare, with only 9 cases reported in the literature. CASE DESCRIPTION: We describe a case of an ectopic TSH-secreting pituitary adenoma located in the nasopharynx in a patient initially presenting with signs and symptoms of hyperthyroidism that persisted despite treatment with antithyroid medications. Magnetic resonance imaging of the pituitary gland was normal, although subsequent review by a neuroradiologist revealed a nodule attached to the posterior septum in the nasopharynx that was, in retrospect, seen on several other magnetic resonance imaging scans. Gallium 68 (68Ga) DOTATATE positron emission tomography/computed tomography showed increased uptake in the nasopharyngeal nodule. The patient underwent resection of the nasopharyngeal mass with remission of hyperthyroidism. On pathology, the resected mass stained positive for TSH and prolactin. CONCLUSIONS: This is the first report of use of 68Ga-DOTATATE positron emission tomography/computed tomography to aid in localizing an ectopic TSH-secreting tumor. Prior studies have shown that 68Ga-DOTATATE positron emission tomography/computed tomography improves detection of small lesions with shorter imaging times and lower radiation doses compared with other modalities. Our case emphasizes the importance of using 68Ga-DOTATATE PET/CT in the diagnosis of ectopic pituitary adenomas, as these tumors can be challenging to diagnose radiographically.