Impact of carotid tortuosity on outcome after endovascular thrombectomy.

BACKGROUND AND OBJECTIVES: Endovascular thrombectomy (EVT) is efficacious in patients with large vessel occlusion stroke (LVO). We explored whether internal carotid (ICA) tortuosity increases the technical difficulty of EVT thereby lowering the chances of successful recanalization and favorable outcomes. PATIENTS AND METHODS: Consecutive patients with LVO and patent ICAs who underwent EVT were included. Carotid tortuosity was determined on pre-EVT CTA and classified by raters blinded to outcomes into: type 1-straight ICA trunk and type 2-severe tortuosity potentially impeding adequate catheter placement. Thrombolysis in cerebral infarction (TICI) 2b-3 was considered successful recanalization, and 90-day-modified Rankin Scale ≤ 2 was considered favorable functional outcome. RESULTS: Among 302 patients (mean age 70 ± 15, median NIHSS 17), 53% had type 1, and 47% type 2 tortuosity. Overall, 85% had successful recanalization. Patients with type 2 tortuosity were significantly older (p < 0.0001) and less frequently achieved successful recanalization (80% vs. 90%; p = 0.019) but had similar outcomes compared with those without tortuosity. On regression analysis, marked tortuosity was associated with lower chances of successful recanalization (OR 0.43 95% CI 0.20-0.92) but had no effect on clinical outcomes. CONCLUSIONS: Carotid tortuosity does not appear to impact the likelihood of favorable functional outcome but may influence recanalization.

Endovascular Ultraviolet Laser-Facilitated Reversal of Vasospasm Induced by Subarachnoid Hemorrhage in Canines.

BACKGROUND: Because treatments for cerebral arterial spasm-a delayed consequence of subarachnoid hemorrhage (SAH)-are clinically inconsistent, we describe here a new method for reversal of arterial spasm, possibly extensible to nitric oxide (NO)-sensitive microvasculature. METHODS: We subjected dogs to the intracisternal double-hemorrhage model of SAH (autologous blood injection on days 1 and 3) and began endovascular treatment of the spasmed basilar artery (BA) on Day 4. A conical-tip fused silica optical fiber was introduced via a microcatheter (inserted femorally) into the proximal vicinity of the spasmed BA. After local saline flushing of blood, an ultraviolet (UV) pulsed laser beam (355 nm Nd:YAG) was focused into the optical fiber and converted into a concentric ring beam, which facilitated endovascular irradiation for 30 s at intensities of 12-20 W/cm2. BA diameters were measured angiographically using a semiautomated routine over the entire BA length as well as the proximal, medial, and distal segments. RESULTS: On Day 4 the BAs had constricted by 21 ± 11%. After UV laser irradiation on Day 4, the constricted BAs dilated to 93 ± 15% of their normal diameters within minutes, and the dilation (91 ± 12%) persisted on Day 5. Most BA segments recovered to their respective baselines after UV irradiation, even when the UV beam was located considerably proximal to the BA origin. At days 4 and 5, the percent BA dilation normalized to Day 4 pre-treatment decreased linearly (by scatter plot, p < 0.02) over a range of about 60 mm from the UV irradiation site. CONCLUSIONS: We conjecture that the vasodilator nitric oxide, produced at high local concentration from its vascular storage forms (chiefly nitrites) by UV laser-induced photoscission, stimulates a wave of arterial dilation, possibly by longitudinal propagation of transnitrosation reactions in the arterial wall, which reverses cerebral vasospasm semi-locally and thus avoids the deleterious effects of systemic treatment.

Neuroendovascular Treatment of Acute Stroke During COVID-19: A Guide From the Frontlines.

Since the initial reports surfaced of a novel coronavirus causing illness and loss of life in Wuhan, China, COVID-19 has rapidly spread across the globe, infecting millions and leaving hundreds and thousands dead. As hospitals cope with the influx of patients with COVID-19, new challenges have arisen as health-care systems care for patients with COVID-19 while still providing essential emergency care for patients with acute strokes and acute myocardial infarction. Adding to this complex scenario are new reports that patients with COVID-19 are at increased risk of thromboembolic complications including strokes. In this article, we detail our experience caring for acute stroke patients and provide some insight into neurointerventional workflow modifications that have helped us adapt to the COVID-19 era.

Neurointerventional Radiology for the Aspiring Radiology Resident: Current State of the Field and Future Directions.

OBJECTIVE: The purposes of this study were to document recent trends in stroke intervention at a tertiary-care facility with a comprehensive stroke center and to analyze current procedure volumes and the employment of specialty providers in neurointerventional radiology (NIR). MATERIALS AND METHODS: Institutional trends in the volume of mechanical thrombectomy were analyzed on the basis of the number of patients who underwent mechanical thrombectomy from 2013 to 2017. To evaluate the current status of mechanical thrombectomy volumes in the United States, the number of patients in the Medicare fee-for-service database who underwent mechanical thrombectomy in 2016 was assessed. The specialty backgrounds of the various providers who performed mechanical thrombectomy were analyzed. Procedure volumes for intracranial stenting, embolization, and vertebral augmentation procedures were assessed. RESULTS: From 2013 to 2017, the total numbers of mechanical thrombectomy procedures for acute ischemic stroke were 19 in 2013 and 111 in 2017. The total volume of mechanical thrombectomy procedures in the Medicare fee-for-service population in 2016 was 7479. For intracranial endovascular procedures, 20,850 were performed in the U.S. Medicare population in 2015 and 22,511 in 2016. Radiologists performed 45% of procedures in 2016; neurosurgeons, 41%; and neurologists, 11%. When the total numbers of percutaneous brain and spine procedures were combined, radiologists performed 41%; neurosurgeons, 23%; and neurologists, 3%. In 2016, there were a total of 220 active NIR staff at the NIR programs with rotating residents or fellows. In these programs, 49% of staff members were neuroradiologists, 41% were neurosurgeons, and 10% were neurologists. Of the 72 NIR departments with confirmed rotating fellows or residents, 14 had only neuroradiologists on staff, six had only neurosurgeons, and one had only neurologists. CONCLUSION: Increasing radiology resident interest and participation in NIR should ensure a steady influx of radiologists into the field, continuing the strong tradition of radiology participation, leadership, and innovation in NIR.

Transcranial Optical Monitoring of Cerebral Hemodynamics in Acute Stroke Patients during Mechanical Thrombectomy.

INTRODUCTION: Mechanical thrombectomy is revolutionizing treatment of acute stroke due to large vessel occlusion (LVO). Unfortunately, use of the modified Thrombolysis in Cerebral Infarction score (mTICI) to characterize recanalization of the cerebral vasculature does not address microvascular perfusion of the distal parenchyma, nor provide more than a vascular "snapshot." Thus, little is known about tissue-level hemodynamic consequences of LVO recanalization. Diffuse correlation spectroscopy (DCS) and diffuse optical spectroscopy (DOS) are promising methods for continuous, noninvasive, contrast-free transcranial monitoring of cerebral microvasculature. METHODS: Here, we use a combined DCS/DOS system to monitor frontal lobe hemodynamic changes during endovascular treatment of 2 patients with ischemic stroke due to internal carotid artery (ICA) occlusions. RESULTS AND DISCUSSION: The monitoring instrument identified a recanalization-induced increase in ipsilateral cerebral blood flow (CBF) with little or no concurrent change in contralateral CBF and extracerebral blood flow. The results suggest that diffuse optical monitoring is sensitive to intracerebral hemodynamics in patients with ICA occlusion and can measure microvascular responses to mechanical thrombectomy.

Microvascular reperfusion during endovascular therapy: the balance of supply and demand.

BACKGROUND: Endovascular therapy (EVT) has revolutionized the treatment of acute stroke, but large vessel recanalization does not always result in tissue-level reperfusion. Cerebral blood flow (CBF) is not routinely monitored during EVT. We aimed to leverage diffuse correlation spectroscopy (DCS), a novel transcranial optical imaging technique, to assess the relationship between microvascular CBF and post-EVT outcomes. METHODS: Frontal lobe CBF was monitored by DCS in 40 patients undergoing EVT. Baseline CBF deficit was calculated as the percentage of CBF impairment on pre-EVT CT perfusion. Microvascular reperfusion was calculated as the percentage increase in DCS-derived CBF that occurred with recanalization. The adequacy of reperfusion was defined by persistent CBF deficit, calculated as: baseline CBF deficit - microvascular reperfusion. A good functional outcome was defined as 90-day modified Rankin Scale score ≤2. RESULTS: Thirty-six of 40 patients achieved successful recanalization, in whom microvascular reperfusion in itself was not associated with infarct volume or functional outcome. However, patients with good functional outcomes had a smaller persistent CBF deficit (median 1% (IQR -11%-16%)) than patients with poor outcomes (median 28% (IQR 2-50%)) (p=0.02). Smaller persistent CBF deficit was also associated with smaller infarct volume (p=0.004). Multivariate models confirmed that persistent CBF deficit was independently associated with infarct volume and functional outcome. CONCLUSIONS: CBF augmentation alone does not predict post-EVT outcomes, but when microvascular reperfusion closely matches the baseline CBF deficit, patients experience favorable clinical and radiographic outcomes. By recognizing inadequate reperfusion, bedside CBF monitoring may provide opportunities to personalize post-EVT care aimed at CBF optimization.

Intraoperative angiography in neurosurgery: temporal trend, access site, and operative indication considerations from a 6-year institutional experience.

BACKGROUND: Historically, the transfemoral approach (TFA) has been the most common access site for cerebral intraoperative angiography (IOA). However, in line with trends in cardiac interventional vascular access preferences, the transradial approach (TRA) and transulnar approach (TUA) have been gaining popularity owing to favorable safety and patient satisfaction outcomes. OBJECTIVE: To compare the efficacy and safety of TRA/TUA and TFA for cerebral and spinal IOA at an institutional level over a 6-year period. METHODS: Between July 2016 and December 2022, 317 angiograms were included in our analysis, comprising 60 TRA, 10 TUA, 243 TFA, and 4 transpopliteal approach cases. Fluoroscopy time, contrast dose, reference air kerma, and dose-area products per target vessel catheterized were primary endpoints. Multivariate regression analyses were conducted to evaluate predictors of elevated contrast dose and radiation exposure and to assess time trends in access site selection. RESULTS: Contrast dose and radiation exposure metrics per vessel catheterized were not significantly different between access site groups when controlling for patient position, operative region, 3D rotational angiography use, and different operators. Access site was not a significant independent predictor of elevated radiation exposure or contrast dose. There was a significant relationship between case number and operative indication over the study period (P<0.001), with a decrease in the proportion of cases for aneurysm treatment offset by increases in total cases for the management of arteriovenous malformation, AVF, and moyamoya disease. CONCLUSIONS: TRA and TUA are safe and effective access site options for neurointerventional procedures that are increasingly used for IOA.

Artery of Davidoff and Schechter: A Large Angiographic Case Series of Dural AV Fistulas.

The artery of Davidoff and Schechter (ADS) is the only meningeal branch of the posterior cerebral artery (PCA), supplying the medial tentorial margin and posterior portions of the falx. Given its small size, it is rarely identified on angiographic studies, unless enlarged in pathologies such as dural arteriovenous fistulas (DAVFs) or vascularized masses. This artery was first described by Wollschlaeger and Wollschlaeger in 1965, and to date, only a few reports have described its significance. The objective of this study is to report our experience with the ADS in dural fistulas from 2 tertiary medical centers and to emphasize the importance of recognizing this artery during angiographic examination of vascular tentorial and posterior fossa lesions. To our knowledge, this report demonstrates the largest angiographic case series published to date, recognizing a total of 7 patients with ADS arising secondary to a posterior fossa or tentorial DAVF and one of the largest reported series of DAVFs supplied by the ADS treated by endovascular and surgical techniques. Our cases validate the importance of prompt identification of the ADS for the diagnosis as well as endovascular treatment of vascular malformations in the posterior fossa and tentorial region.

Diagnosis and treatment of vein of Galen aneurysmal malformations.

INTRODUCTION: Vein of Galen aneurysmal malformations (VGAM) are rare but clinically significant intracranial arteriovenous shunt lesions that most often present in neonates and infants. METHODS: Retrospective clinical data were collected for patients evaluated with a diagnosis of VGAM from 1994 to 2007. RESULTS: Thirteen patients with VGAM were evaluated from 1994 to 2007. Seven patients presented emergently with medically intractable cardiac failure, and six were treated in the first 2 weeks of life. Five children treated after this period (1.5-31 months of age) manifested enlarging head circumference, abnormal development, or subarachnoid hemorrhage. Eleven patients were managed endovascularly. Four disease or procedure-related complications occurred. Two complications were associated with poor outcome, both of which occurred in patients treated at less than 2 weeks of age. Two other patients experienced transient neurological deficits with no evidence of permanent sequelae. Outcome in the six patients treated emergently in the first 2 weeks of life included two patients who developed normally, one with mild to moderate neurological deficits, one with severe neurological deficits, and two deaths. Outcome in the five older patients (treated between 1.5 and 31 months) was considerably better than in the group treated early and included three with normal outcome and two with mild neurological deficits. CONCLUSIONS: Contemporary endovascular techniques remain the preferred treatment for VGAM in all age groups. Early diagnosis and multimodality treatment are essential for the best management and treatment of the complex constellation of clinical problems often arising from this disorder.

Association of intracranial arteriovenous malformation embolization with more rapid rate of perfusion in the peri-nidal region on color-coded quantitative digital subtraction angiography.

BACKGROUND: Hemodynamic alterations post-embolization of intracranial arteriovenous malformations (AVMs) may cause delayed edema/hemorrhage in brain parenchyma adjacent to the lesion. OBJECTIVE: To quantify and compare cerebral perfusion changes in the peri-AVM territory pre- and post-embolization using color-coded quantitative digital subtraction angiography (q-DSA). METHODS: Pediatric intracranial AVM embolization procedures performed over a 5 year period were included. DSA images of all patients were retrospectively assessed using syngo iFlow. Regions of interest (ROI) were selected on anteroposterior and lateral q-DSA views: three in the peri-AVM region; two in parenchyma distant from the AVM. Time-to-peak (TTP) contrast enhancement of ROIs and ∆TTP (TTP at the selected ROI minus TTP at either the ipsilateral internal carotid/vertebral artery) were measured. RESULT: 19 pediatric patients with 19 AVMs (9 males/10 females, mean age 12 years) underwent intracranial AVM embolization: 15/19 AVMs were supplied by the anterior circulation and 4/19 by the posterior circulation. Blood flow was significantly slower post-embolization in the draining vein (19/19) (p<0.01), and the venous sinus outflow (17/19) (p<0.01), by mean difference of 2.01±1.31 s and 1.74±2.04 s. There was significantly increased peri-AVM parenchymal perfusion post-embolization (∆TTP=2.20±0.48 s) compared with pre-embolization (∆TTP=2.52±0.42 s), by an average ∆TTP of 0.33±0.53 s (p=0.014). In contrast, there was no perfusion difference (∆TTP=0.03±0.20 s, p=0.8) between pre- and post-embolization in the distant parenchyma. The size of the AVM was not correlated with change in peri-nidal parenchymal perfusion (r=-0.136, p=0.579). CONCLUSION: This study demonstrates more rapid perfusion in the peri-nidal brain parenchyma post-embolization of the AVM, which supports the theory that increased perfusion in normal tissue surrounding the AVM after embolization may underlie some post-procedural complications.

Vascular imaging of the spine in the US Medicare population: Catheter and MR angiography volumes from 2004 to 2016.

AIMS: The purpose of our study was to analyze utilization trends and physician specialty distribution in spinal catheter angiography and magnetic resonance angiography in the Medicare fee-for-service population. METHODS: Data from the CMS Physician/Supplier Procedure Summary Master Files for 2004 to 2016 were used for this study. The Current Procedural Terminology version 4 codes for spinal magnetic resonance angiography (72159) and spinal catheter angiography (75705) were used to analyze the volumes of these procedures. Using Medicare's 108 specialty code, we compared procedure volumes among physician specialties. Data analysis was performed using SAS version 9.3 for Windows. RESULTS: The volume of spinal catheter angiography performed was 4758 in 2004, peaked at 6869 in 2012, and dropped to 6656 in 2016. Overall, the volume of spinal catheter angiography increased by 40% from 2004 to 2016. Radiologists performed the majority of these procedures (3736 or 56.1%) in 2016, followed by neurosurgeons (2456 or 36.9%), and neurologists (346 or 5.2%). The spinal magnetic resonance angiography volume fluctuated between 0 and 1 from 2004 to 2009, then precipitously increased to 40 in 2010, peaked at 133 in 2011, and declined to 81 in 2016. The volume of spinal magnetic resonance angiography procedures increased by 8000% from 2004 to 2016, with radiologists performing the majority of them. CONCLUSION: Our results show that spinal catheter angiography volumes continue to rise in the Medicare fee-for-service population, and are largely performed by radiologists, neurosurgeons, and neurologists. Although spinal magnetic resonance angiography volumes have started to increase, they comprise only a small fraction of studies performed for vascular evaluation of the spine.

Subarachnoid Hemorrhage as Result of Retrocorporeal Artery Aneurysm Rupture: Rare Sequel of Subclavian Steal Syndrome.

BACKGROUND: Subclavian steal phenomenon can cause retrograde flow in the vertebral artery as a result of ipsilateral occlusion of the subclavian artery. This phenomenon has various clinical presentations, such as claudication of the affected extremity or intermittent vertebrobasilar ischemia. Aneurysm formation in the spinal cord circulation is exceptionally rare but may occur secondary to collateral formation in subclavian steal syndrome. CASE DESCRIPTION: The case presented herein is a 53-year-old male who presented with headache and severe neck pain. Imaging studies revealed that the patient had subarachnoid hemorrhage in the perimedullary and cervicomedullary cisterns and extending to C3-C7 ventrally. Computed tomography angiography reconstruction demonstrated an aneurysmally dilated vessel dorsal to the C6 vertebral body within the spinal canal. Catheter-based angiography of the right subclavian artery demonstrated retrograde flow within the left vertebral artery and confirmed proximal left subclavian artery occlusion, findings diagnostic of subclavian steal. Further, a branch of the right thyrocervical trunk supplied a retrocorporeal artery collateral to the left vertebral artery, which also contributed to the anterior spinal artery. CONCLUSIONS: After endovascular coiling of the aneurysm, the patient had no neurologic deficits or postoperative complications. Postoperative angiography revealed complete obliteration with no residual aneurysm. Imaging further demonstrated patency of the radiculomedullary (anterior spinal) artery.

Type V Dural Arteriovenous Fistula Supplied by the Artery of Wollschlaeger and Wollschlaeger Causing Cervical Myelopathy and Quadriparesis.

BACKGROUND: The artery of Wollschlaeger and Wollschlaeger is a tentorial branch of the superior cerebellar artery that is usually not visualized on conventional cerebral angiography, unless it is pathologically enlarged. It can be recruited as part of the blood supply to tentorial dural arteriovenous fistulas (AVFs), although this occurs infrequently. CASE DESCRIPTION: Here we report the clinico-radiologic evaluation and treatment of a 48-year-old man referred to our institution for hitherto workup negative progressive, relapsing quadriparesis. This represents the first reported case of cervical myelopathy caused by venous congestion from a type V dural AVF supplied by the artery of Wollschlaeger and Wollschlaeger. CONCLUSIONS: The anatomic discrepancy between the symptomatic spinal cord lesion and the etiologic intracranial fistula frequently results in delayed care in cases of myelopathy due to intracranial dural AVFs. Familiarity with these disorders and of their pathophysiologic mechanisms is important to avoid unnecessary diagnostic delays.

Middle cerebral artery vasospasm: transcranial color-coded duplex sonography versus conventional nonimaging transcranial Doppler sonography.

OBJECTIVE: To prospectively compare accuracies of transcranial color-coded duplex sonography (TCCS) and transcranial Doppler sonography (TCD) in the diagnosis of middle cerebral artery (MCA) vasospasm. DESIGN: Prospective blinded head-to-head comparison TCD and TCCS methods using digital subtraction angiography (DSA) as the reference standard. SETTING: Department of Radiology in a tertiary university health center in a metropolitan area. PATIENTS: Eighty-one consecutive patients (mean age, 53.9 +/- 13.9 years; 48 women). The indication for DSA was subarachnoid hemorrhage in 71 patients (87.6%), stroke or transient ischemic attack in five patients (6.2%), and other reasons in five patients (6.2%). INTERVENTIONS: The MCA was graded as normal, narrowed <50%, and >50% using DSA. The accuracy of ultrasound methods was estimated by total area (Az) under receiver operator characteristic curve. To compare sensitivities of ultrasound methods, McNemar's test was used with mean velocity thresholds of 120 cm/sec for the detection of less advanced, and 200 cm/sec for the more advanced MCA narrowing. MEASUREMENTS AND MAIN RESULTS: Angiographic MCA narrowing 50% in 10 of 135 arteries. Accuracy of TCCS was insignificantly higher than that of TCD in the detection of 50% narrowing, total Az for mean velocity being 0.83 +/- 0.05, 0.77 +/- 0.05, and 0.95 +/- 0.02, 0.86 +/- 0.08, respectively. Sensitivity of TCCS at commonly used threshold of 120 cm/sec for less advanced MCA spasm was significantly better than that of TCD at similar specificity, 55% vs. 39%, p = 0.038, whereas at a threshold of 200 cm/sec used for more advanced spasm, sensitivities and specificities of both methods were not different. CONCLUSION: The accuracy of TCCS and TCD is similar, but TCCS is more sensitive than TCD in the detection of MCA spasm. Sensitivity of both techniques in the detection of mild and more advanced spasm using 120 cm/sec and 200 cm/sec thresholds, respectively, is poor; however, a larger sample is required to increase precision of our sensitivity estimates.

Significance of the absent vertebral artery T2 flow void on cervical spine MRI in atraumatic patients without acute neurological symptoms.

PURPOSE: Loss of the T2 vertebral artery flow void can be an ominous sign in patients with trauma. However, the significance of an absent vertebral artery flow void is less clear when discovered incidentally in patients without trauma or acute neurological symptoms. The purpose of this study was to review retrospectively the results of additional imaging and clinical evaluation in atraumatic patients without acute neurological symptoms found to have an incidentally discovered absent vertebral artery flow void on magnetic resonance imaging. MATERIALS AND METHODS: An imaging database was reviewed for absent vertebral artery flow voids in atraumatic cervical spine magnetic resonance images. Imaging and long-term clinical follow-up were recorded. RESULTS: Fifty-four patients were included in the study. All patients had clinical follow-up and 22 patients (40% of cases) had vascular imaging follow-up. Nine patients had a hypoplastic but patent vertebral artery on follow-up vascular imaging, and no further action was taken. Ten patients had evidence of stenosis or occlusion of the vertebral artery on follow-up imaging, none with acute neurological symptoms or new symptoms/subsequent change in management during follow-up. Three additional patients had vertebral artery dissections on follow-up imaging, but all of them had acute neurological symptoms at the time of imaging and acute infarcts on current or subsequent magnetic resonance imaging. The other 32 patients had clinical follow-up and remained asymptomatic throughout the study period, without change in management. CONCLUSION: In the absence of trauma or acute neurological symptoms an absent vertebral artery flow void has a low likelihood of altering patient management.

Neurovascular emergencies in the elderly.

Neurovascular diseases are major causes of disability and death in the elderly; many present as medical emergencies. With the continuing growth of the geriatric population, there has been increasing interest in the impact of aging on the cerebrovascular system. Recent advances in the clinical neurosciences have demonstrated that neurovascular emergencies in the elderly often are amenable to treatment; neuroimaging plays a critical role in diagnosis and neurointerventional techniques are becoming increasingly important therapeutic options. This article provides an overview of some of the common neurovascular disorders in the elderly that require urgent evaluation and treatment, with an emphasis on the expanding role for interventional neuroradiology in their management.

Symptomatic high-flow arteriovenous fistula after a C-2 fracture. Case report.

Spinal arteriovenous fistulas (AVFs) are relatively uncommon lesions that are often diagnosed in a delayed fashion. The authors present a cause of a symptomatic high-flow AVF that developed in a patient after traumatic injury to the upper cervical spine. The patient presented to the trauma bay after a motor vehicle collision, and was found to have a C-2 fracture involving the transverse foramen. Although the patient was neurologically intact on presentation, 6 hours after admission weakness developed on his left side. Imaging studies demonstrated complete transection of the distal cervical aspect of the right vertebral artery (VA) at the base of C-2, with antegrade and retrograde flow into a direct AVF, resulting in early filling of the right internal jugular vein and other external draining veins. The patient was treated endovascularly with coil occlusion of the VA both proximal and distal to the transection. The patient's weakness improved over the next 7 days. At the 12-week follow-up examination, the patient's fractures had healed and he was neurologically intact.

Meta-analysis of cranial CT scans in children. A mathematical model to predict radiation-induced tumors.

OBJECTIVE: We aimed to estimate the risks of radiation exposure from a single head CT scan to children of different ages. MATERIALS AND METHODS: We constructed a multistate time-dependent Markov model to simulate the course of children exposed to a head CT. The relevant literature was reviewed for probabilities, which were used to calculate tumor types, latencies after exposure and outcomes in the model. Where multiple approximations of the same probability had been reported, meta-analytic techniques were employed to compute pooled estimates. The model was then used to calculate the effect of the radiation exposure on life expectancy and quality of life for children following head CT at different ages. RESULTS: The tumors likely to be induced by low-level cranial irradiation include thyroid carcinoma (47%), meningioma (34%) and glioma (19%). According to the model, a single head CT is likely to cause one of these tumors in 0.22% of 1-year-olds, 30% of whom will consequently die. The exposure will shorten the life expectancy of all exposed 1-year-olds by an average of 0.04 years and their expected quality of life by 0.02 quality-adjusted life years. The risks of radiation exposure diminish for older children. CONCLUSIONS: The model predicts that the effective radiation dose from a single head CT is capable of inducing a thyroid or brain tumor in an infant or child. These tumors can severely impact both quality of life and life expectancy. Care should be taken before ordering CT scans in children, particularly in infants and toddlers.

Actionable vascular and other incidental findings on CTA in patients undergoing acute stroke intervention.

Providing a fast and accurate diagnosis of acute large-vessel occlusion on computed tomography angiograms (CTAs) is essential for timely intervention and good stroke outcomes. However, the detection and appropriate management of incidental findings are also important parts of any clinical radiology practice and can greatly affect patient care. The intricate anatomy covered by CTAs of the head and neck coupled with the time pressures of acute stroke diagnosis creates an environment in which unrelated, important findings can potentially be missed. The purpose of our study was to document clinically actionable incidental findings on CTA in 225 patients undergoing acute stroke intervention. After institutional review board approval, a retrospective six-year review of CTAs of the head and neck in patients undergoing acute stroke intervention was performed for actionable incidental vascular and nonvascular findings. A total of 225 patients undergoing acute stroke intervention with documented intracranial large-vessel occlusion on CTAs were consecutively enrolled in the study. Incidental vascular findings were identified in 17 of 225 patients (7.5%, 95% confidence interval 5% to 12%). Previously unreported aneurysms ranging from 2 mm to 10 mm in size represented 18 of 19 vascular findings in these patients. Incidental nonvascular findings were identified in 32 patients (14%, 95% confidence interval 5% to 12%). These included malpositioned support lines and tubes; pneumothorax; interstitial lung disease; newly diagnosed metastatic disease; nasopharyngeal, parotid, and pituitary masses; and cervical spine compression fractures. CTAs of the head and neck in patients undergoing acute stroke intervention contain a relatively high frequency of vascular and nonvascular incidental findings requiring further follow-up, and therefore should be evaluated carefully and systematically.

Anomalous Origin of the Right Vertebral Artery from the Right Common Carotid Artery.

The anomalous origin of the right vertebral artery (VA) from the right common carotid artery (CCA) is a rare vascular anomaly, which is usually clinically asymptomatic and found incidentally during angiographic examinations. This anomaly is invariably associated with an aberrant right subclavian artery (RSCA). Approximately 31 cases have been reported in the literature. We present a case of a right VA originating from the right CCA in a patient with Down syndrome and discuss the imaging findings, embryological etiology of the anomaly, as well as its implications for endovascular/surgical treatment.