Cryptic asymptomatic parasellar high signal on time-of-flight MR angiography: how to resolve the clinical conundrum.

PURPOSE: Hyperintense parasellar signal on time-of-flight MR angiography (TOF-MRA) in asymptomatic patients may be due to a variety of nonpathological causes and mimic parasellar high flow signal in pathological arteriovenous shunts at the cavernous sinus (CSAVS). This creates a clinical conundrum between diagnosing an aggressive yet asymptomatic CSAVS subtype against exposing patients without CSAVS to potential complications of an invasive angiographic evaluation. We reviewed common nonpathological causes of hyperintense parasellar signal and contrast their imaging features against those of pathological CSAVS and proposed a systemic approach to resolve such conundrum. METHODS: The anatomy of the cavernous sinus (CS) and causes of nonpathological parasellar hyperintense TOF-MRA signal are described and explained with case reviews, illustrations, and reference to published literature where appropriate. Imaging features of proven CSAVS are juxtaposed to aid in radiological differentiation. An algorithm is proposed to manage patients with such incidental TOF-MRA findings. RESULTS: The margins, contour, extent, intensity, and stippling appearance aid in evaluation of pathological versus incidental TOF-MRA parasellar signal, and differentiation of CSAVS from nonpathological causes. Pertinent radiological features are summarized in a table. For unresolved cases suspected for CSAVS, further evaluation with dynamic time-resolved contrast-enhanced MRA is proposed and depicted in a decision tree flow chart. CONCLUSION: Familiarity with the differentiating radiological features and a systematic management workflow could aid in resolving the clinical conundrum of findings of cryptic asymptomatic parasellar TOF-MRA high signal, while facilitating timely detection of the asymptomatic CSAVS.

External Validation of Hematoma Expansion Scores in Spontaneous Intracerebral Hemorrhage in an Asian Patient Cohort.

BACKGROUND: Hematoma expansion (HE) occurs in approximately one-third of patients with intracerebral hemorrhage (ICH) and is known to be a strong predictor of neurological deterioration as well as poor functional outcome. This study aims to externally validate three risk prediction models of HE (PREDICT, 9-point, and BRAIN scores) in an Asian population. METHODS: A prospective cohort of 123 spontaneous ICH patients admitted to a tertiary hospital (certified stroke center) in Singapore was recruited. Logistic recalibrations were performed to obtain updated calibration slopes and intercepts for all models. The discrimination (c-statistic), calibration (Hosmer-Lemeshow test, le Cessie-van Houwelingen-Copas-Hosmer test, Akaike information criterion), overall performance (Brier score, R2), and clinical usefulness (decision curve analysis) of the risk prediction models were examined. RESULTS: Overall, the recalibrated PREDICT performed best among the three models in our study cohort based on the novel matrix comprising of Akaike information criterion and c-statistic. The PREDICT model had the highest R2 (0.26) and lowest Brier score (0.14). Decision curve analyses showed that recalibrated PREDICT was more clinically useful than 9-point and BRAIN models over the greatest range of threshold probabilities. The two scores (PREDICT and 9-point) which incorporated computed tomography (CT) angiography spot sign outperformed the one without (BRAIN). CONCLUSIONS: To our knowledge, this is the first study to validate HE scores, namely PREDICT, 9-Point and BRAIN, in a multi-ethnic Asian ICH patient population. The PREDICT score was the best performing model in our study cohort, based on the performance metrics employed in this study. Our findings also showed support for CT angiography spot sign as a predictor of outcome after ICH. Although the models assessed are sufficient for risk stratification, the discrimination and calibration are at best moderate and could be improved.

Off-label use of large diameter Concerto fibered coils through a 0.017 inch microcatheter for transvenous embolization of indirect carotid-cavernous fistulas: two case reports.

BACKGROUND: A carotid-cavernous fistula is an abnormal communication between the arteries and veins within the cavernous sinus. While conservative management may be prudent in low risk cases, many patients require intervention and endovascular embolization has evolved as the preferred method of treatment. Embolization can be performed via either the transarterial or transvenous approach. One major challenge of the transvenous approach is the complex and variable compartmentation of the cavernous sinus, which often requires the use of low profile microcatheters to navigate and reach the fistulous point. Fibered coils are also preferred when performing transvenous embolization of carotid-cavernous fistula, as they are of higher thrombogenicity and allow for faster occlusion of the fistula. However, most low profile (0.017-inch) microcatheters are not able to deploy fibered coils based on the manufacturer's instructions. CASE PRESENTATION: We present two successful cases of off-label use of Medtronic Concerto fibered coils via a 0.017-inch microcatheter during transvenous embolization of carotid-cavernous fistula in a 60-year-old and an 80-year-old Chinese female, respectively. CONCLUSION: Our case series highlight the possibility of deploying large diameter (up to 10 mm) Concerto fibered coils through a low profile (0.017-inch) microcatheter in an off-label manner for transvenous embolization of indirect carotid-cavernous fistula.

Responsive Web-based Breast Imaging Core Curriculum for International Radiology Residents with Self-Assessment: A Pilot Study.

RATIONALE AND OBJECTIVES: Lack of uniformity in radiology resident education is partially attributable to variable access to subspecialty education. Web-based courses improve standardization, but with growing emphasis on competency based education, more evaluation of their effectiveness is needed. We created a responsive web-based breast imaging curriculum for radiology residents including self-assessment and a satisfaction survey. MATERIALS AND METHODS: Two global academic institutions collaboratively developed a breast imaging curriculum to address radiology residents' educational needs. This virtual course comprised 11 video lectures, nine didactic (with attached pre-test and post-test assessments) and two case review sessions. In April 2020, this optional curriculum was made available to all 56 radiology residents in one residency program cluster in Singapore, to be accessed alongside the breast imaging rotation as a supplement. A voluntary anonymous satisfaction survey was provided upon completion. RESULTS: A total of 39 of the 56 radiology residents (70%) completed the course. For the average score of nine lectures (maximum score 5), there was a significant increase in mean pre and post - test scores (mean = 2.2, SD = 0.7), p < 0.001. The proportion of residents with improvement between the pre-test score and the post-test score ranged from 74% to 100% (mean, 84%). Thirty three of the 39 participants (85%) completed the satisfaction survey, and all agreed or strongly agreed that the curriculum increased their knowledge of breast imaging. CONCLUSION: This web based breast imaging curriculum supplement was viewed positively by participating residents and improved their self-assessed knowledge. Curriculum access could be expanded to improve global radiology education.

SingHealth Radiology Archives pictorial essay Part 2: gastroenterology, musculoskeletal, and obstetrics and gynaecology cases.

The Singapore Health Services cluster (SingHealth) radiology film archives are a valuable repository of local radiological cases dating back to the 1950s. Some of the cases in the archives are of historical medical interest, i.e. cerebral angiography in the workup of patients with hemiplegia. Other cases are of historical social interest, being conditions seen during earlier stages of Singapore's development, i.e. bound feet. The archives form a unique portal into the development of local radiology as well as the national development of Singapore. A selection from the archives is published in commemoration of the International Day of Radiology in 2020, as well as the 200th anniversary of the Singapore General Hospital in 2021. This pictorial essay comprises gastroenterology, musculoskeletal and obstetrics and gynaecology cases from the archives.

The Wandering Charm Needle.

Charm needles, otherwise known as susuk, are small pin like objects worn subcutaneously, thought to bring magic powers, bringing health, wealth, beauty, and other benefits to the wearer. These talismans are fairly common in South-East Asia, and are generally thought to be benign entities with few clinical sequela. In fact, no known complications have ever been reported in the literature, as susuk are typically composed of biologically inert precious metals and rarely migrate from their origin. Herein, we detail the first ever reported case of a complication from a charm needle, involving a middle aged Chinese female who had a charm needle subcutaneously inserted into the occipital scalp, which eventually migrated through the skull and into her left cerebellar hemisphere. Our aim is to familiarize readers to this peculiar phenomenon not widely practiced in the western world, and to highlight that charm needles are not as benign as initially conceived. To the best of our knowledge, this case demonstrates the first reported complication of a charm needle in the English medical literature.

Review of Junior Resident Plain Film Reporting and Audit in Singapore.

BACKGROUND: Graduate medical education in Singapore recently underwent significant restructuring, leading to the accreditation of residency programs by the Accreditation Council for Graduate Medical Education-International (ACGME-I). In radiology, this involved a change in teaching and quality assurance of plain film (PF) reporting. PF reported by junior residents (postgraduate year 1-3) are subject to a 50% random audit. To date, national data on junior resident performance in PF reporting have not been published. OBJECTIVE: We reviewed performance in PF reporting under the current teaching and audit framework. METHODS: Retrospective review of junior resident reported PF audit data from all 3 radiology residency programs in Singapore. The number of residents audited, number of PF reported and audited, and major discrepancy rates were analyzed. RESULTS: On average, 86 440 PF were audited annually nationwide from an estimated 184 288 junior resident-reported PF. Each program trained between 4 to 24 junior residents annually (mean 15), averaging about 44 each year nationwide. A mean of 28 813 PF were audited annually in each program (range 4355-50 880). An estimated mean of 4148 PF (range 1452-9752) were reported per junior resident per year, about 346 PF per month. The major discrepancy rate ranged from 0.04% to 1.13% (mean 0.34%). One resident required remediation in the study period. CONCLUSIONS: Structured residency training in Singapore has produced a high level of junior resident competency in PF interpretation.

SingHealth Radiology Archives pictorial essay Part 1: cardiovascular, respiratory and neurological cases.

The Singapore Health Services cluster (SingHealth) radiology film archives are a valuable repository of local radiological cases dating back to the 1950s. Some of the cases in the archives are of historical medical interest, i.e. cerebral angiography in the workup of patients with hemiplegia. Other cases are of historical social interest, being conditions seen during earlier stages of Singapore's development, i.e. bound feet. The archives form a unique portal into the development of local radiology as well as the national development of Singapore. A selection from the archives is published in 2020 in commemoration of the 20th anniversary of the formation of SingHealth, the 55th National Day of Singapore, and the 125th anniversary of the International Day of Radiology. This pictorial essay comprises cardiovascular, respiratory and neurological cases from the archives.

Clinics in diagnostic imaging (193). Sporadic Creutzfeldt-Jakob disease (sCJD).

A 68-year-old man presented with a three-week history of rapidly progressive dementia, gait ataxia and myoclonus. Subsequent electroencephalography showed periodic sharp wave complexes, and cerebrospinal fluid assay revealed the presence of a 14-3-3 protein. A probable diagnosis of sporadic Creutzfeldt-Jakob disease was made, which was further supported by magnetic resonance (MR) imaging of the brain showing asymmetric signal abnormality in the cerebral cortices and basal ganglia. The aetiology, clinical features, diagnostic criteria, various MR imaging patterns and radiologic differential diagnosis of sporadic Creutzfeldt-Jakob disease are discussed in this article.

Anterior condylar confluence dural arteriovenous fistula: a rare cause of hoarseness.

Hoarseness secondary to an anterior condylar confluence (ACC) dural arteriovenous fistula (DAVF) has not been previously described. We present a 58-year-old patient with a 3-week history of progressive unilateral left-sided headaches and hoarseness. Nasolaryngoscopy and CT neck showed the presence of unilateral vocal cord palsy with no identifiable cause along the expected course of the recurrent laryngeal nerve. MRI revealed an incidental finding of abnormal serpiginous vessels in the left hypoglossal canal which led to a diagnostic cerebral angiogram, confirming the presence of an ACC DAVF. The patient underwent transvenous coil embolisation with subsequent resolution of arteriovenous shunting and symptoms. Follow-up MRI at 6 months showed no recurrence and there was complete resolution of clinical symptoms.

Finite Element Analysis Predicts Large Optic Nerve Head Strains During Horizontal Eye Movements.

PURPOSE: We combined finite element (FE) analysis and dynamic magnetic resonance imaging (MRI) to estimate optic nerve head (ONH) strains during horizontal eye movements, and identified factors influencing such strains. We also compared ONH strains (prelamina, lamina cribrosa, and retrolamina strains) induced by eye movements to those induced by IOP. METHODS: The ocular globes and orbits of a healthy subject were visualized during horizontal eye movements (up to 13°), using dynamic MRI. A baseline FE model of one eye was reconstructed in the primary gaze position, including details from the orbital and ONH tissues. Finite element-derived ONH strains induced by eye movements were compared to those resulting from an IOP of 50 mm Hg. Finally, a FE sensitivity study was performed, in which we varied the stiffness of all ONH connective tissues, to understand their influence on ONH strains. RESULTS: Our models predicted that, during horizontal eye movements, the optic nerve pulled the ONH posteriorly. Optic nerve head strains following a lateral eye movement of 13° were large and higher than those resulting from an IOP of 50 mm Hg. These results held true even with variations in connective tissue stiffness. We also found that stiff sclerae reduced lamina cribrosa and prelamina strains during eye movements, but stiff optic nerve sheaths significantly increased those strains. CONCLUSIONS: Our models predicted high ONH strains during eye movements, which were aggravated with stiffer optic nerve sheaths. Further studies are needed to explore links between ONH strains induced by eye movements and axonal loss in glaucoma.

WITHDRAWN: Primary CNS lymphoma and high-grade glioma: differentiation using perfusion and proton spectroscopic MR imaging.

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

Infections of the deep neck spaces.

Deep neck infections (DNI) have a propensity to spread rapidly along the interconnected deep neck spaces and compromise the airway, cervical vessels and spinal canal. The value of imaging lies in delineating the anatomical extent of the disease process, identifying the source of infection and detecting complications. Its role in the identification and drainage of abscesses is well known. This paper pictorially illustrates infections of important deep neck spaces. The merits and drawbacks of imaging modalities used for assessment of DNI, the relevant anatomy and the possible sources of infection of each deep neck space are discussed. Certain imaging features that alter the management of DNI have been highlighted.

Is myo-inositol a measure of glial swelling after stroke? A magnetic resonance study.

PURPOSE: To determine whether the hypothesis that the phenomenon of persistent cytotoxic edema in the subacute stage of ischemic stroke is in fact associated with the glial population. This is done by assessing the evolution of both the apparent diffusion coefficient (ADC) and the glial-specific marker myo-inositol (Ins) in a group of patients, and by comparing the results with the total cellular density by means of the creatine (Cre) level. MATERIAL AND METHODS: Twenty-two patients with stroke in the territory of the middle cerebral artery were each examined once only at a time ranging from eight hours to six days following the onset of symptoms. Lesion-to-contralateral values of ADC were obtained based on diffusion-weighted echo-planar imaging. Short TE single-voxel proton magnetic resonance ((1)H MR) spectroscopy was used for quantification of cerebral metabolites in infarcted regions. Their levels were also compared with those in homotopic contralateral regions. RESULTS: In the stroke lesion, there was a significant correlation between ADC and the Ins level, albeit less pronounced than that for Cre. During different pathophysiological stages between 12 hours and three days, the Ins-to-Cre ratio increased by a factor of two and returned to apparently normal thereafter. CONCLUSION: Our study provides the first demonstration of a relationship between persistent cytotoxic edema and the glial population in the context of cell swelling due to osmotic imbalance in stroke patients.