High resolution magnetic resonance imaging for exposing facial nerve zonal vulnerability to microbleeds: A rare cause of facial palsy.

Background We report a case of hypertensive microbleeds strategically located at the attached segment (AS) and root entry zone (REZ) at the left facial nerve causing facial paralysis. Case Report A 60-year-old woman presented with sudden onset left facial paralysis. Medical history was significant for poorly controlled hypertension secondary to bilateral adrenal hyperplasia (primary hyperaldosteronism). The patient was initially treated for presumptive Bell's palsy. Subsequent magnetic resonance imaging of the brain and internal auditory canal showed two microbleeds at the left cerebellopontine angle. Dedicated coronal T1 magnetization prepared rapid acquisition gradient echo and T2 sampling perfection with application optimized contrasts using different flip angle evolution sequences revealed two acute microbleeds located at the attached AS and REZ of the left facial nerve. The patient experienced only partial recovery from House-Brackmann grade IV facial paralysis at presentation to a House-Brackmann grade III facial paralysis at 1 year of follow up. Conclusions To the best of the authors' knowledge, this is the first reported case of facial paralysis caused by microbleeds directly affecting the vulnerable AS and REZ facial nerve segments. We discuss the zonal microanatomy of the facial nerve and the crucial role of high resolution MRI for diagnosis.

Susceptibility weighted imaging in acute cerebral ischemia: review of emerging technical concepts and clinical applications.

Susceptibility weighted imaging (SWI) is an essential magnetic resonance imaging sequence in the assessment of acute ischemic stroke. In this article, we discuss the physics principals and clinical application of conventional SWI and multi-echo SWI sequences. We review the research evidence and practical approach of SWI in acute ischemic stroke by focusing on the detection and characterization of thromboembolism in the cerebral circulation. In addition, we discuss the role of SWI in the assessment of neuroparenchyma by depiction of asymmetric hypointense cortical veins in the ischemic territory (surrogate tissue perfusion), detection of existing microbleeds before stroke treatment and monitoring for hemorrhagic transformation post-treatment. In conclusion, the SWI sequence complements other parameters in the stroke magnetic resonance imaging protocol and understanding of the research evidence is vital for practising stroke neurologists and neuroradiologists.

Serial magnetic resonance imaging findings of intracerebral spread of listeria utilising subcortical U-fibres and the extreme capsule.

We present a case of Listeria monocytogenes cerebral abscess with axonal spread via the subcortical U-fibres and extreme capsule on magnetic resonance imaging, with follow-up studies demonstrating serial reduction in oedema and enhancement pattern of the white-matter fibre tracts following antimicrobial treatment. We discuss the microbiological mechanism of bacterial mobility to account for these unique imaging features. Recognition of this distinct pattern of spread of L. monocytogenes cerebral abscess may aid in diagnosis and enable early microbiological culture and treatment.

Principles and Clinical Application of Dual-energy Computed Tomography in the Evaluation of Cerebrovascular Disease.

Dual-energy computed tomography (DECT) simultaneously acquires images at two X-ray energy levels, at both high- and low-peak voltages (kVp). The material attenuation difference obtained from the two X-ray energies can be processed by software to analyze material decomposition and to create additional image datasets, namely, virtual noncontrast, virtual contrast also known as iodine overlay, and bone/calcium subtraction images. DECT has a vast array of clinical applications in imaging cerebrovascular diseases, which includes: (1) Identification of active extravasation of iodinated contrast in various types of intracranial hemorrhage; (2) differentiation between hemorrhagic transformation and iodine staining in acute ischemic stroke following diagnostic and/or therapeutic catheter angiography; (3) identification of culprit lesions in intra-axial hemorrhage; (4) calcium subtraction from atheromatous plaque for the assessment of plaque morphology and improved quantification of luminal stenosis; (5) bone subtraction to improve the depiction of vascular anatomy with more clarity, especially at the skull base; (6) metal artifact reduction utilizing virtual monoenergetic reconstructions for improved luminal assessment postaneurysm coiling or clipping. We discuss the physical principles of DECT and review the clinical applications of DECT for the evaluation of cerebrovascular diseases.

Duplication of the superficial femoral artery: comprehensive review of imaging literature and insight into embryology.

An extremely rare case of duplicated superficial femoral artery (SFA) was incidentally observed on computed tomography angiogram (CTA) of the lower limbs for presurgical planning for an osteomyocutaneous fibula flap in a patient with T4a oropharyngeal squamous cell carcinoma (SCC). To our knowledge, this is the sixth reported case in the imaging literature. We performed a comprehensive review of the English literature and discuss the underlying embryological origin underpinning this rare anatomical variant.

Susceptibility-Weighted Imaging of Glioma: Update on Current Imaging Status and Future Directions.

Susceptibility-weighted imaging (SWI) provides invaluable insight into glioma pathophysiology and internal tumoral architecture. The physical contribution of intratumoral susceptibility signal (ITSS) may correspond to intralesional hemorrhage, calcification, or tumoral neovascularity. In this review, we present emerging evidence of ITSS for assessment of intratumoral calcification, grading of glioma, and factors influencing the pattern of ITSS in glioblastoma. SWI phase imaging assists in identification of intratumoral calcification that aids in narrowing the differential diagnosis. Development of intratumoral calcification posttreatment of glioma serves as an imaging marker of positive therapy response. Grading of tumors with ITSS using information attributed to microhemorrhage and neovascularity in SWI correlates with MR perfusion parameters and histologic grading of glioma and enriches preoperative prognosis. Quantitative susceptibility mapping may provide a means to discriminate subtle calcifications and hemorrhage in tumor imaging. Recent data suggest ITSS patterns in glioblastoma vary depending on tumoral volume and sublocation and correlate with degree of intratumoral necrosis and neovascularity. Increasingly, there is a recognized role of obtaining contrast-enhanced SWI (CE-SWI) for assessment of tumoral margin in high-grade glioma. Significant higher concentration of gadolinium accumulates at the border of the tumoral invasion zone as seen on the SWI sequence; this results from contrast-induced phase shift that clearly delineates the tumor margin. Lastly, absence of ITSS may aid in differentiation between high-grade glioma and primary CNS lymphoma, which typically shows absence of ITSS. We conclude that SWI and CE-SWI are indispensable tools for diagnosis, preoperative grading, posttherapy surveillance, and assessment of glioma.

18F-FDG PET/CT in a Patient With Glomus Vagale Paraganglioma and Eisenmenger Syndrome: Searching for the Missing Link?

There is emerging evidence linking cyanotic heart disease and pheochromocytoma-paraganglioma through a proposed hypoxia pathway. We present a 59-year-old woman with known Eisenmenger syndrome secondary to delayed diagnosis of ventricular septal defect, in whom F-FDG PET/CT provided comprehensive evaluation of both an F-FDG-avid left glomus vagale paraganglioma and also increased right ventricular myocardial glucose metabolism in response to severe pulmonary hypertension in the chronic shunting state.

High-Resolution Diffusion Tensor Imaging and Tractography in Joubert Syndrome: Beyond Molar Tooth Sign.

BACKGROUND: We undertook diffusion tensor imaging analysis of brainstem fiber tracts in two Joubert syndrome patients. METHODS: Two Joubert syndrome patients underwent magnetic resonance imaging brain examination with diffusion tensor imaging. Imaging findings were compared with five age- and sex-matched control subjects with approval from the institutional ethic committee. The medical history and clinical examination findings in both patients were documented. RESULTS: Diffusion tensor imaging analysis of the first patient demonstrated absence of the dorsal pontocerebellar tract and thinning of the middle cerebral peduncle. Diffusion tensor imaging analysis of the second child revealed thinning of the both the dorsal pontocerebellar and ventral pontocerebellar tract. Both patients exhibited thickened and horizontally oriented superior cerebellar peduncles. The superior cerebellar peduncles also failed to decussate in the mesencephalon. CONCLUSION: Pontocerebellar tract abnormalities in Joubert syndrome patients have not been previously recognized. The difference in the pontocerebellar tract between the two Joubert syndrome patients suggests a spectrum of severity of pontine axonal migration abnormality.

High resolution CT study of the chorda tympani nerve and normal anatomical variation.

OBJECTIVE: The aim of this study was to define the normal anatomical variation of the course of the CTN through the mastoid temporal bone on high resolution CT (HRCT). MATERIALS AND METHODS: Retrospective review of 27 consecutive normal HRCT bilateral temporal bones (n = 54, 14 males and 13 females, mean age 41 years) reconstructed at 0.4-mm slice thickness specifically measuring (1) origin of CTN from the posterior genu of the facial nerve (CNVII) and (2) the lateral-most position of the CTN from the mastoid segment of CNVII. RESULTS: The mean distance of the CTN origin from the mastoid segment of CNVII was 11.5 mm (standard deviation, SD = 3.2, 95% CI 10.7-12.3) with no statistically significant difference between the left and right side observed (p = 0.08). The most lateral distance of the CTN from CNVII was a mean of 1.3 mm (SD = 0.6, 95% CI 1.2-1.7), range 0-2.5 mm and again no statistical significance between contralateral sides was observed (p = 0.11). These measurements demonstrated an excellent level of agreement between observers as assessed by intraclass correlation calculation. CONCLUSIONS: Reproducible measurements demonstrate variability of the CTN in both its origin from the mastoid segment of CNVII and its lateral-most course. Precise description of the course of the CTN with HRCT may be useful for planning of otologic surgery and limiting inadvertent nerve injury.

Pontine Tegmental Cap Dysplasia: MR Evaluation of Vestibulocochlear Neuropathy.

Pontine tegmental cap dysplasia (PTCD) is recently recognized as a rare congenital brain stem malformation with typical neuroimaging hallmarks of ventral pontine hypoplasia and vaulted pontine tegmentum projecting into the fourth ventricle. PTCD patients also demonstrate variable cranial neuropathy with predilection for involvement of the vestibulocochlear and facial nerves. We present a case of PTCD diagnosed on MRI in the neonatal period. During early infancy, the patient displayed features of multiple cranial neuropathies and bilateral hearing loss. At the age of 2, the patient underwent further MRI assessment with dedicated high resolution T2 SPACE sequence to delineate the cranial nerve deficiencies.

Scedosporium apiospermum endophthalmitis: diffusion-weighted imaging in detecting subchoroidal abscess.

PURPOSE: To describe the imaging appearance of Scedosporium apiospermum (S. apiosermum) endophthalmitis in an immunocompetent female who underwent high resolution magnetic resonance imaging (MRI) of the orbits and showed subchoroidal abscess on diffusion-weighted imaging. METHODS: WE HIGHLIGHT UTILITY OF MRI SEQUENCES: diffusion-weighted imaging (DWI), apparent diffusion coefficient (ADC), fluid-attenuated inversion recovery (FLAIR), and contrast-enhanced magnetic resonance imaging (CE-MRI) in the detection of a subchoroidal abscess and characterization of the inflammatory change of the uveal tract. Vitreous culture grew S. apiospermum. CONCLUSION: Fungal endophthalmitis is a rare but aggressive process. Clinically, it can mimic other disease entities such as neoplasm. To the best of our knowledge, this is the first case that describes the CT and MRI imaging findings of S. apiospermum endophthalmitis. We emphasize the use of DWI and ADC sequences in the detection of subchoroidal abscess.

Smoking habits of radiotherapy patients: did the diagnosis of cancer make an impact and is there an opportunity to intervene?

OBJECTIVES: To investigate the impact of a cancer diagnosis on smoking habits in patients receiving radiotherapy and assess the opportunity to intervene. METHODS: One hundred consecutive patients were interviewed. They included patients newly diagnosed with cancer of any type and receiving radiotherapy. Detailed information was collected including smoking habits before and after the diagnosis, the timing of and reasons for any changes. We also asked about patients' view of the role of the radiation oncologist in smoking cessation and the opportunities for intervention. Analysis of results involved simple descriptive statistics. RESULTS: Although there were only 14 current smokers, only two had decided to quit. Five smokers decreased smoking, six did not change and one increased smoking. One non-smoker (1/34) took up smoking. Nearly all changes occurred within the first 30 days of diagnosis. Most (79%, 11/14) smokers believed that the treating radiation oncologist should discuss smoking cessation with their patients and that the ideal timing is at either the first consultation or when decisions about treatment have been finalised. CONCLUSIONS: The diagnosis of cancer can motivate patients to reduce smoking, but few quit altogether and a smaller number increase or even take up smoking. These changes occur early after receiving a diagnosis of cancer. Patients with a smoking history believed that the treating radiation oncologist should discuss smoking cessation with their patients and that the ideal timing is at the first consultation. The periodic nature of treatments and consultations at radiation oncology centres suggest there is the potential for an effective smoking cessation programme.