Prediction of Hemorrhage after Successful Recanalization in Patients with Acute Ischemic Stroke: Improved Risk Stratification Using Dual-Energy CT Parenchymal Iodine Concentration Ratio Relative to the Superior Sagittal Sinus.

BACKGROUND AND PURPOSE: Brain parenchymal hyperdensity on postthrombectomy CT in patients with acute stroke can be due to hemorrhage and/or contrast staining. We aimed to determine whether iodine concentration within contrast-stained parenchyma compared with an internal reference in the superior sagittal sinus on dual-energy CT could predict subsequent intracerebral hemorrhage. MATERIALS AND METHODS: Seventy-one patients with small infarct cores (ASPECTS ≥ 7) and good endovascular recanalization (modified TICI 2b or 3) for anterior circulation large-vessel occlusion were included. Brain parenchymal iodine concentration as per dual-energy CT and the percentage of contrast staining relative to the superior sagittal sinus were recorded and correlated with the development of intracerebral hemorrhage using Mann-Whitney U and Fisher exact tests. RESULTS: Forty-three of 71 patients had parenchymal hyperdensity on initial dual-energy CT. The median relative iodine concentration compared with the superior sagittal sinus was significantly higher in those with subsequent intracerebral hemorrhage (137.9% versus 109.2%, P = .007). By means of receiver operating characteristic analysis, a cutoff value of 100% (iodine concentration relative to the superior sagittal sinus) enabled identification of patients going on to develop intracerebral hemorrhage with 94.75% sensitivity, 43.4% specificity, and a likelihood ratio of 1.71. CONCLUSIONS: Within our cohort of patients, the relative percentage of iodine concentration at dual-energy CT compared with the superior sagittal sinus was a reliable predictor of intracerebral hemorrhage development and may be a useful imaging biomarker for risk stratification after endovascular treatment.

Imaging-Guided Superior Ophthalmic Vein Access for Embolization of Dural Carotid Cavernous Fistulas: Report of 20 Cases and Review of the Literature.

Dural carotid cavernous fistulas are usually treated via a transvenous approach through the inferior petrosal sinus. Surgical exposure and direct access to the superior ophthalmic vein have been previously described in situations in which conventional transvenous access, including the inferior petrosal sinus, is not possible. In this retrospective study of 20 patients, we report our results of imaging-guided percutaneous superior ophthalmic vein access in dural carotid cavernous fistula treatment. The superior ophthalmic vein was accessed after direct percutaneous puncture under sonographic guidance in 16 patients and biplane roadmap guidance in 4 patients. In all 20 patients, it was possible to access the superior ophthalmic vein and cure the dural carotid cavernous fistula. Two patients developed a retrobulbar hematoma after postseptal puncture, which required emergency lateral canthothomy. In our experience, direct imaging-guided percutaneous superior ophthalmic vein access is a safe alternative approach for treatment in situations in which conventional transvenous approaches are not possible.

Imaging and Surgical Findings in Patients with Hemi-Laryngopharyngeal Spasm and the Potential Role of MRI in the Diagnostic Work-Up.

BACKGROUND AND PURPOSE: Hemi-laryngopharyngeal spasm is a recently discovered condition characterized by episodic coughing and unilateral throat contractions that may lead to severe stridor. These symptoms are caused by a vascular compression of the ipsilateral vagus nerve, typically the PICA. Microvascular decompression of the vagus nerve has been demonstrated to be a potential cure for this neurovascular compression syndrome. The main aim of this study was to clarify the role of MR imaging in the diagnostic work-up of this rare condition. MATERIALS AND METHODS: We describe the imaging and surgical findings of 3 patients from our prospective case series of patients with hemi-laryngopharyngeal spasm from 2015 to 2017. Second, the imaging data of 100 patients (control cohort) with symptoms unrelated to hemi-laryngopharyngeal spasm were reviewed to investigate the rate and degree of neurovascular conflict of the vagus nerve. RESULTS: All patients with hemi-laryngopharyngeal spasm reported to date have had vascular compression of the vagus nerve due to the PICA. In the control cohort, there was a good interrater agreement in scoring the "contact" and "compression" of the vagus nerve (κ = 0.73. P = < .001). The frequency of contact or compression of the vagus nerve was approximately 50%. The PICA was the most frequent vessel involved in 74%. CONCLUSIONS: The presence of unilateral neurovascular contact or compression of the vagus nerve does not confirm the diagnosis of hemi-laryngopharyngeal spasm. The MR imaging finding of ipsilateral vascular compression of the vagus nerve is a necessary but not sufficient finding for the diagnosis of hemi-laryngopharyngeal spasm.

Reversible cerebral vasoconstriction syndrome: an important and common cause of thunderclap and recurrent headaches.

Reversible cerebral vasoconstriction syndrome is an intracranial vascular manifestation of a wide variety of diseases. It is the second most common cause of thunderclap headache, the most common cause of recurrent severe secondary headaches, and, in patients <60 years of age, has been reported as the commonest cause of isolated convexity subarachnoid haemorrhage. Radiologically, its key feature is vasoconstriction of the intracranial vessels, a dynamic process that is typically maximal at 2 weeks, varies in its distribution over the course of the disease, and typically resolves after 3 months. It can have haemorrhagic and ischaemic complications and sometimes occurs in concert with posterior reversible encephalopathy syndrome. It also has important associations with dissection and migraine. Rarer atypical cases can present with mild headache, no headache at all, or even a comatose state. This paper provides a detailed review of this syndrome, its pathophysiology, differential diagnosis, imaging findings, and work-up. It also describes the role that high-resolution magnetic resonance imaging (MRI) techniques can have in diagnosing the disease and emphasises the central role that all radiologists have in detecting this important and underdiagnosed condition.

Syringomyelia Fluid Dynamics and Cord Motion Revealed by Serendipitous Null Point Artifacts during Cine MRI.

Dynamic MR imaging was used to evaluate a cervical syrinx in an adolescent boy with an associated hindbrain herniation. Null artifacts were present on one of the sequences that allowed simultaneous high-resolution visualization of syrinx fluid motion and the anatomy of the syrinx walls. A brief review of the theories of syrinx formation and propagation is provided with a comment on why the Williams "slosh" theory of syrinx progression is supported by our unique imaging.

Back pain in children and adolescents.

Back pain is a common symptom in children and adolescents. Here we review the important causes, of which defects and stress reactions of the pars interarticularis are the most common identifiable problems. More serious pathology, including malignancy and infection, needs to be excluded when there is associated systemic illness. Clinical evaluation and management may be difficult and always requires a thorough history and physical examination. Diagnostic imaging is obtained when symptoms are persistent or severe. Imaging is used to reassure the patient, relatives and carers, and to guide management.

The many faces of posterior reversible encephalopathy syndrome.

The classic imaging findings of posterior reversible encephalopathy syndrome (PRES) are of bilateral parietal and occipital subcortical vasogenic oedema, and are well established in the literature. As experience with PRES grows, varied and atypical presentations are being increasingly described. This pictorial review illustrates the variable presentations of PRES, including cases with atypical imaging findings. We illustrate cases of PRES with varying distributions of vasogenic oedema as well as cases with atypical imaging findings, such as variations of haemorrhage and restricted diffusion. Atypical imaging findings should not dissuade the diagnosis of PRES in the appropriate clinical situation, and knowledge of the varied appearance and atypical findings of PRES allows the radiologist to make this diagnosis.

Intracranial transthecal subarachnoid fat emboli and subarachnoid haemorrhage arising from a sacral fracture and dural tear.

We present the case of a 28-year-old man with an unusual aetiology of lipid-dense material in the subarachnoid space. CT of the head at presentation was normal. MRI of the spine revealed a defect in the dura at L5/S1, with avulsed left L5 and S1 nerve roots. Haematoma and marrow fat were observed in close relation to the dural tear adjacent to the sacral fracture. Head CT and MRI subsequently demonstrated new lipid-dense material and haemorrhage in the subarachnoid space after sacral instrumentation, presumably owing to transthecal displacement of fatty marrow.

Resolution of existing intimal plaque in a patient with carotidynia.

We present a case of carotidynia that was imaged with 3 techniques: sonography, CT angiography, and gadolinium-enhanced MR imaging. We describe a previously unreported finding, the resolution of an intimal plaque noted on imaging at the time of initial presentation, presumably due to changes induced by the healing phase of the carotid inflammatory process.

Calcified cerebral emboli.

Intracranial calcifications may represent calcified cerebral emboli. Calcified emboli may be overlooked even though cerebral CT is widely used as a stroke assessment. We report 4 cases of calcified cerebral emboli and demonstrate the value of CT in the diagnosis and temporal evaluation of such emboli.

Diffusion-weighted imaging findings in Balo concentric sclerosis.

Balo concentric sclerosis is a rare demyelinating disease. Pathognomonic features have been previously described. Diffusion-wighted imaging findings have not been previously described in Balo concentric sclerosis. We describe the diffusion-weighted imaging findings in a 45-year-old lady with Balo concentric sclerosis. Diffusion-weighted imaging offers insight into the possible pathophysiology of this rare disease.

Multifocal venous malformations: two interesting case presentations.

INTRODUCTION: Multiple venous abnormalities involving the orbit, head and neck regions have been previously described. We present two similar cases of low-flow orbital venous vascular malformations (VVMs) in association with multiple low-flow VVMs in the head and neck as well as in the peripheral limb. Literature search revealed that this association has not been previously reported. METHODS: Retrospective review of two patients with multifocal VVMs was performed. RESULTS: Case 1: A 46 year-old Chinese female had a history of multiple vascular lesions involving the right orbit, the tongue, right neck region, right arm and one finger. Valsalva manoeuvre resulted in distension of these lesions. CT scan of the orbits demonstrated bilateral low-flow VVMs. CT angiogram also revealed multiple developmental venous anomalies in the brain. Case 2: A 16 year-old Chinese female had a history of multiple venous malformations involving the neck, left forearm and oral region. Dynamic manoeuvres demonstrated the distensible nature of these lesions. MRI scans of the orbits showed bilateral extraconal low-flow VVMs. Similar mass lesions were seen on MRI scans of the neck. CONCLUSIONS: Multiple cervicofacial venous malformations with developmental abnormalities of the intracranial venous system have been described previously. However, their associations with similar VVMs in the peripheral limb regions have not been reported. Our cases illustrate this rare association. VVMs appear to be benign in nature with symptoms mainly due to mass effect. Management can be conservative in the absence of any sight threatening complication.