Post-Traumatic Carotid Artery Dissection Begins at the Skull Base: A Case Report.

Cervical artery dissection is a rare complication of head and neck trauma. Though it is an infrequent cause of ischaemic stroke, it is more common among the young with cerebral ischaemia. The usual location of carotid dissection is just beyond the carotid bulb. We report a case of post-traumatic internal carotid dissection that began at the base of the skull after blunt head trauma from a road traffic accident. The patient is a 25-year-old right-handed lady who, 2 days after the accident, developed dysphasia and right-sided limb weakness. She had no significant past medical history. Magnetic resonance imaging (MRI) showed acute ischaemic stroke in the internal watershed regions of the left cerebral hemisphere. MR angiogram revealed focal near-occlusion of the left internal carotid artery at the base of the skull just prior to its entry into the petrous temporal bone. There were no skull fractures. She progressed despite anticoagulation. The location of the site of dissection at the base of the skull is likely due to stresses on the carotid intima at this point during flexion-extension-rotation that occurs during head injury, as this is where the internal carotid artery is tethered to the skull. Rapid recognition of symptoms of cerebral ischaemia among patients with blunt head trauma is needed to allow prompt investigation and institution of relevant therapies.

"Cortical" Wrist Drop due to a Cerebral Peduncle Infarct.

Wrist drops are usually due to a peripheral neuropathy affecting the radial nerve. Cortical wrist drops may occur, usually due to a lesion in the contralateral hand area of the motor cortex. We report a unique case of "cortical" wrist drop due to an acute infarction of the contralateral cerebral peduncle. The patient is a 70-year-old gentleman with the vascular factors of hypertension, hyperlipidaemia, and prior cerebellar strokes, who developed sudden onset of right wrist weakness without numbness. Neurological examination showed a right wrist and finger drop. Nerve conduction study of the radial nerve was normal. MRI brain revealed an acute infarct in the medial part of the left cerebral peduncle, extending slightly to the medial thalamus; there were also old medial posterior cerebellar infarcts. Time of flight MR angiography was normal, with hypoplastic right vertebral artery. Echocardiography was normal but for a dilated right atrium. Electrocardiogram was normal, and 24-hour Holter monitoring detected infrequent atrial and ventricular ectopics. X-ray wrist showed an old ulnar styloid fracture. Nerve conduction study of the radial nerve was normal. He was switched from aspirin to clopidogrel and underwent rehabilitation. The cerebral peduncle should not be forgotten when attempting to anatomically localise the site of the lesion when evaluating a patient with a wrist drop.

Imaging in Pulsatile Tinnitus: Case Based Review.

Tinnitus refers to auditory perception of internal origin. It is a relatively common problem and affects men and women equally. Clinically, it may be divided as pulsatile or non-pulsatile and subjective and objective. Although pulsatile tinnitus (PT) is less common, it is more likely to be associated with underlying vascular tumors, lesions or anomalies. Imaging forms the baseline for evaluation of objective tinnitus, primarily in the form of computed tomography or magnetic resonance imaging. We present a review of common causes of PT, along with emphasis on key imaging findings.

Epstein-Barr virus (EBV)-related smooth muscle tumors of central nervous system--a report of two cases and review of literature.

Epstein-Barr virus-related smooth muscle cell tumors (EBV-SMTs) are rare albeit increasingly recognized tumors in immunocompromised patients. We report on the imaging features of EBV-SMTs occurring in the central nervous system (CNS) in two patients. Central areas of T2 prolongation, surrounding vasogenic edema, mass effect on adjacent neuroparenchyma, dural tails, and underlying bone erosions were the notable imaging findings. Besides the usual differentials of extraaxial tumors like meningioma, hemangiopericytoma, and lymphoma, CNS EBV-SMTs should be considered in immunocompromised patients.

Imaging in infections of the head and neck.

Infections of the head and neck vary in their clinical course and outcome because of the diversity of organs and anatomic compartments involved. Imaging plays a central role in delineating the anatomic extent of the disease process, identifying the infection source, and detecting complications. The utility of imaging to differentiate between a solid phlegmonous mass and an abscess cannot be overemphasized. This review briefly describes and pictorially illustrates the typical imaging findings of some important head and neck infections, such as malignant otitis externa, otomastoiditis bacterial and fungal sinusitis, orbital cellulitis, sialadenitis, cervical lymphadenitis, and deep neck space infections.

A method in the madness in ultrasound evaluation of thyroid nodules.

Around 50% of the population harbour thyroid nodules on ultrasonography, up to 7% of which may be malignant irrespective of size. While fine-needle aspiration biopsy is reliable, subjecting every thyroid nodule to this procedure is not cost-effective. Hence, ultrasonography is used primarily to characterise thyroid nodules, whereas nodules that have suspicious features are subject to a fine-needle aspiration biopsy. The presence of microcalcifications, macrocalcifications, irregular margins, 'taller-than-wide' shape, marked hypoechogenicity and intrinsic vascularity are features that render a thyroid nodule suspicious for malignancy. Spongiform appearance and the presence of colloid plugs or purely cystic nodules are considered features of benignity. In this article, these aforementioned sonographic features of malignancy and benignity are pictorially illustrated and a basic approach to dealing with solitary and multiple thyroid nodules is highlighted.

Spinal cavernous malformations: magnetic resonance imaging and associated findings.

INTRODUCTION: We reviewed the clinical features, brain and spinal cord magnetic resonance (MR) imaging findings and associated abnormalities in six patients with spinal cavernous malformations (CMs). METHODS: Lesions were defined on gradient-recalled echo (GRE) images but measured on T2-weighted images performed on 1.5- and 3-tesla clinical scanners. RESULTS: Four patients had associated multiple cranial CMs and one patient had multiple spinal CMs. All spinal CMs were predominantly hypointense on GRE images, and most were predominantly hyperintense and surrounded by hypointense edge on T2-weighted images. Other associations included asymptomatic vertebral body and splenic haemangiomas. CONCLUSION: We conclude that intramedullary spinal CMs typically have 'mulberry' or 'popcorn' appearances similar to those of cranial CM. The presence of associated haemangioma or familial cranial CM syndrome on MR imaging may suggest the correct diagnosis without requiring invasive investigations.

Thyroid nodules: risk stratification for malignancy with ultrasound and guided biopsy.

Replacing palpating fingers with an ultrasound (US) probe has resulted in an epidemic of thyroid nodules. Despite the high prevalence of thyroid nodules in the general population, thyroid malignancy is rare. Although no imaging modality can accurately predict the nature of every nodule, high-resolution US is the most sensitive, easily available and cost-effective diagnostic test available to detect thyroid nodules, measure their dimensions and identify their structure. The presence of calcifications, irregular spiculated outline, hypoechogenicity in a solid nodule, chaotic intranodular vascularity and an elongated shape are well-known US features of malignancy in thyroid nodules. Cervical lymph node metastasis and extrathyroidal extension of a thyroid nodule are highly specific for malignancy but seen infrequently. Spongiform nodules, purely or predominantly cystic nodules, nodules with well-defined hypoechoic halo and echogenic as well as isoechoic nodules are usually benign. None of the US characteristics have 100% accuracy in detecting or excluding malignancy. Fine-needle biopsy is currently the best triage test for pre-operative evaluation of a thyroid nodule. There is no significant difference in the risk for malignancy between palpable and non-palpable nodules and size is not a reliable indicator for their malignant potential. The best tool for risk stratification for malignancy in thyroid nodules is US and guided biopsy of nodules with suspicious imaging features. This is especially relevant in patients with multinodular goitre.

Differential diagnosis for bilateral abnormalities of the basal ganglia and thalamus.

The basal ganglia and thalamus are paired deep gray matter structures that may be involved by a wide variety of disease entities. The basal ganglia are highly metabolically active and are symmetrically affected in toxic poisoning, metabolic abnormalities, and neurodegeneration with brain iron accumulation. Both the basal ganglia and thalamus may be affected by other systemic or metabolic disease, degenerative disease, and vascular conditions. Focal flavivirus infections, toxoplasmosis, and primary central nervous system lymphoma may also involve both deep gray matter structures. The thalamus is more typically affected alone by focal conditions than by systemic disease. Radiologists may detect bilateral abnormalities of the basal ganglia and thalamus in different acute and chronic clinical situations, and although magnetic resonance (MR) imaging is the modality of choice for evaluation, the correct diagnosis can be made only by taking all relevant clinical and laboratory information into account. The neuroimaging diagnosis is influenced not only by detection of specific MR imaging features such as restricted diffusion and the presence of hemorrhage, but also by detection of abnormalities involving other parts of the brain, especially the cerebral cortex, brainstem, and white matter. Judicious use of confirmatory neuroimaging investigations, especially diffusion-weighted imaging, MR angiography, MR venography, and MR spectroscopy during the same examination, may help improve characterization of these abnormalities and help narrow the differential diagnosis.

Lacrimal glands: size does matter!

A 40-year-old woman presented with vague headaches and blurred vision. Contrast-enhanced magnetic resonance imaging of the brain revealed bilaterally symmetrical diffuse enlargement of the lacrimal glands. A fine needle biopsy of the lacrimal gland was consistent with sarcoidosis. Although, isolated lacrimal gland involvement is rare, it may be the initial clinical presentation of sarcoidosis, as seen in this patient. Imaging plays a vital role in these unsuspected cases and careful evaluation of the lacrimal glands with dedicated thin section, fat suppressed, axial and coronal orbital imaging, may help identify a pathological cause and avoid a delay in diagnosis.

Dual Energy CT and its use in neuroangiography.

The dual energy CT (DECT) technology has been recently employed in the form of two X-ray sources of different energies to enhance the contrast between adjacent structures. Its use in the cardiac arena has been widely highlighted due to the higher temporal resolution. However, it may also be used in the craniocervical and peripheral vasculature for better differentiation between contrast-enhanced vascular lumina and calcified plaques, in the characterisation of ureteric stones, and in the evaluation of hepatic lesions. The objective of this paper is to revisit DECT physics, review the literature and discuss its use in CT neuroangiography with case illustrations from our institution, and impact on dose savings.

Antenatal 3-dimensional sonographic diagnosis of fetal oropharyngeal teratoma.

We report a case of a large fetal oropharyngeal teratoma in a 19-week fetus evaluated with 3-dimensional (3D) sonography. The 3D sonographic surface and maximum mode rendering of the tumor allowed detailed visualization of the mass lesion and thus enabled active patient participation in the management of the pregnancy.

Early antenatal diagnosis of spina bifida presenting with a "step" in the posterior contour of an 8-week embryo.

We report a case of spina bifida in the upper thoracic spine with an accompanying meningocoele suspected at 8 weeks' gestation via transvaginal sonography and confirmed at 13 weeks' gestation via 3-dimensional sonography. The fetal cranial vault and intracranial structures were normal. The only finding in the 8-week sonogram was a subtle angulation or "step" in the posterior contour of the embryo; this may be attributed to kyphosis, which often accompanies this condition. The presence of a "step" in the fetal contour must alert the sonologist to the possibility of spina bifida. To our knowledge, this is the earliest antenatal diagnosis of spina bifida.

Two cases of anomalous origins of left coronary artery with a course between the aortic root and the free standing subpulmonary infundibulum on CT coronary angiography.

Two cases of anomalous origins of the left coronary artery have been demonstrated on a CT coronary angiogram. In one case the left main coronary artery arose from the right aortic sinus of valsalva, separate from the right coronary artery. In the second case there was a single coronary artery arising from the right aortic sinus of valsalva. In both these rare cases, the left main coronary artery traversed between the aortic root and the freestanding subpulmonary infundibulum and then divided into its regular branches. These cases show well, the left main artery actually coursing free of the crista supraventricularis portion of the outlet septum. This is contrary to the commonly used classifications and descriptions, which describe the anomalous coronary artery actually traversing through the outlet septum.