Cerebral CT Angiography Research Articles

ISCHEMIC CEREBROVASCULAR ACCIDENT IN A NONAGENARY PATIENT

Acute cerebrovascular attack (CVA) is the second cause of death in the world and generates high costs in its treatment and recovery, as well as a great socioeconomic impact, since it is the main cause of longterm disability. Although simple brain computed tomography (CT) is still the image recommended by international guidelines for the initial evaluation and decision-making on the management of patients with suspected stroke, in recent years there have been extraordinary advances in timely diagnosis and early stroke with new tools that range from the standardization of cerebral computed tomography angiography as one of the main studies in the initial approach to the use of brain tomography and magnetic resonance imaging (MRI) perfusion techniques, which make it possible to establish the nucleus of the infarct and the potentially salvageable surrounding area, so it is possible to offer therapies that provide the patient with functionality and quality of life in the medium and long term. Taking into account the above, we are encouraged to present this case, of an elderly patient who presented this pathology, where the intestinal ileum was also added. Objective: To describe cerebral infarction in a nonagenarian affected patient. Design: Prospective, observational in a single center. Methodology: This is a systematic review of cerebral infarction in a nonagenarian patient, emphasizing its clinical characteristics and short-term complications. The information and images obtained belong to the medical personnel in charge of the case, whose reinforcements rest on the statistical package Excel, Word and JPG.

Metallic Component Preserving Algorithm Based on the Cerebral Computed Tomography Angiography in Aneurysm Surgery.

The purpose of this study was to investigate the viability of the proposed method in preventing the loss of metallic components including the clip and coil in cerebral computed tomography angiography (CTA). Forty patients undergoing surgery for aneurysms carried metallic materials. The proposed method is based on conventional bone subtraction CTA (BS-CTA) system. Briefly, the position of metal components was determined using the threshold value and a region of interest (ROI). An appropriate threshold was used to separate the background from the target materials based on the Otsu method. A three-dimensional (3D) rendering was performed from the proposed BS-CTA data carrying the extracted target information. The accuracy of clip and coil region measured using the dice similarity coefficient (DSC) and bidirectional Hausdorff distance (HD) is reported. The metallic components of the proposed BS-CTA were significantly visualized in various patient cases. Quantitative evaluation using the proposed method is based on the mean DSC of 0.93 with a standard deviation (SD) of ±0.05 (e.g., maximum value = 0.99, minimum value = 0.75, 95% confidence interval (CI) = 0.91 to 0.95, and all p < 0.05). The mean HD was 1.50 voxels with an SD of ± 0.58 (e.g., maximum value = 5.95, minimum value = 0.12, 95% CI = 1.10 to 1.90, and all p < 0.05). The proposed method demonstrates effective segmentation of the metallic component and application to the existing conventional BS-CTA system.

Reducing amount of contrast agent after compression of right brachial artery using a blood pressure cuff in computed tomography cerebrovascular angiography.

To invastgate feasibility of low-dose contrast agent in cerebral computed tomography angiography (CTA) to alleviate side effects. Siemens' Somatom Definition AS+CT scanner, Heine's blood pressure monitor G7-M237 (BP cuff) and Ultravist contrast agent (370 mg Iodine/ml) are used. CTA is acquired using following scan parameters including slice thickness of 1mm, image acquisition parameters of 128×0.6 mm, pitch size of 0.8 mm, 175 effective mAs, 120 kVp tube voltage, scan delay time of 3 seconds, and the scan time of 4 seconds. This study is conducted by securing the IV route in the left antecubital vein before injection of contrast agent, wrapping BP cuff around the branchial artery of the opposite right arm after setting the pressure to 200 mmHg. Then, the injection rate of the contrast agent is fixed at 4.5 cc/sec and contrast agent was injected in three different amounts (70, 80, and 100 cc). Bp cuff is released from this moment when HU value reachs 100. In this study, the mean HU values measured from common carotid artery are 412.45±5.89 when injecting 80cc contrast agent and using BP cuff and 399.64±5.51 when injecting 100 cc contrast agenet and not using BP cuff, respectively. In middle cerebral artery M1, the mean HU values are 325.23±38.29 when injecting 80cc contrast agent and using BP cuff and 325.00±30.63 when injecting 100cc contrast agent blood and not using pressure cuff, respectively. Difference of mean HU values is not statistically significant (p > 0.05) with and without using BP cuff. This study demonstrates that reducing amount of contrast agent is possible when the right brachial artery is compressed using BP cuff. Study results indicate that reducing 20% injection of contrast agent in CT cerebrovascular angiography can still yield comparable imaging results with conventional contrast angent usage, which implies that less side effects are expected with a contrast agent injection. Thus, this study can serve as a reference for potential reducing side effect during CT cerebrovascular angiography.

A case of acute ischemic stroke in moyamoya syndrome associated with Graves’ disease: Is there a role for anti-dsDNA antibodies?

The coexistence of Moyamoya syndrome (MMS) and Graves’ disease (GD) is uncommon. Here, we report a case of a 41-year-old Filipino female, who presented with thyrotoxicosis and acute ischemic stroke. Based on her clinical presentation, cerebral computed tomography angiography, and thyroid function tests, she was diagnosed with MMS and GD. Her Burch-Wartofsky point scale score was 30, suggesting an impending thyroid storm. Antithyroid therapy was started with her neurological status deterioration initially, but after controlling the thyroid storm, the patient’s neurological status stabilized. She remained stable till she travelled to her country. We hypothesized that MMS in a patient with GD is mediated through anti-dsDNA antibodies, by altering key biological mechanisms, that is, inflammation, neutrophil extracellular traps, and apoptosis that drive a distinctive and coordinated immune and vascular activation. To the best of our knowledge, this is the first case of MMS associated with GD reported in Qatar. Keywords: Acute stroke, Graves’ disease, Moyamoya disease, Moyamoya syndrome, Thyrotoxicosis.

Acute Ischemic Stroke and CT Cerebral Angiography: Management and Relationship

Acute Ischemic Stroke and CT Cerebral Angiography: Management and Relationship

Early Diagnosis of Acute Ischemic Stroke by Brain Computed Tomography Perfusion Imaging Combined with Head and Neck Computed Tomography Angiography on Deep Learning Algorithm.

The purpose of the research was to discuss the application values of deep learning algorithm-based computed tomography perfusion (CTP) imaging combined with head and neck computed tomography angiography (CTA) in the diagnosis of ultra-early acute ischemic stroke. Firstly, 88 patients with acute ischemic stroke were selected as the research objects and performed with cerebral CTP and CTA examinations. In order to improve the effect of image diagnosis, a new deconvolution network model AD-CNNnet based on deep learning was proposed and used in patient CTP image evaluation. The results showed that the peak signal-to-noise ratio (PSNR) and feature similarity (FSIM) of the AD-CNNnet method were significantly higher than those of traditional methods, while the normalized mean square error (NMSE) was significantly lower than that of traditional algorithms (P < 0.05). 80 cases were positive by CTP-CTA, including 16 cases of hyperacute ischemic stroke and 64 cases of acute ischemic stroke. The diagnostic sensitivity was 93.66%, and the specificity was 96.18%. The cerebral blood flow (CBF), cerebral blood volume (CBV), and the mean transit time (MTT) in the infarcted area were significantly greater than those in the corresponding healthy side area, and the time to peak (TTP) was significantly less than that in the corresponding healthy side area (P < 0.05). The cerebral perfusion parameters CBF, TTP, and MTT in the penumbra were significantly different from those in the infarct central area and the corresponding contralateral area, and TTP was the most sensitive (P < 0.05). To sum up, deep learning algorithm-based CTP combined with CTA could find the location of cerebral infarction lesions as early as possible to provide a reliable diagnostic result for the diagnosis of ultra-early acute ischemic stroke.

CT Angiography Manual Multiplanar Vessel Diameter Measurement vs. Semiautomated Perpendicular Area Minimal Caliber Computation of Internal Carotid Artery Stenosis.

Objective: To determine the diagnostic agreement of CT angiography (CTA) manual multiplanar reformatting (MPR) stenosis diameter measurement and semiautomated perpendicular stenosis area minimal caliber computation of extracranial internal carotid artery (ICA) stenosis.Methods: We analyzed acute cerebral ischemia CTA at our tertiary stroke center in a 12-month period. Prospective NASCET-type stenosis grading for each ICA was independently performed using (1) MPR to manually determine diameters and (2) perpendicular stenosis area with minimal caliber semiautomated computation to grade luminal constriction. Corresponding to clinically relevant NASCET strata, results were grouped into severity ranges: normal, 1–49%, 50–69%, and 70–99%, and occlusion.Results: We included 647 ICA pairs from 330 patients (median age of 74 [66–80, IQR]; 38–92 years; 58% men; median NIHSS 4 [1–9, IQR]). MPR diameter and semiautomated caliber measurements resulted in stenosis grades of 0–49% in 143 vs. 93, 50–69% in 29 vs. 27, 70–99% in 6 vs. 14, and occlusion in 34 vs. 34 ICAs (p = 0.003), respectively. We found excellent reliability between repeated manual CTA assessments of one expert reader (ICC = 0.997; 95% CI, 0.993–0.999) and assessments of two expert readers (ICC = 0.972; 95% CI, 0.936–0.988). For the semiautomated vessel analysis software, both intrarater reliability and interrater reliability were similarly strong (ICC = 0.981; 95% CI, 0.952–0.992 and ICC = 0.745; 95% CI, 0.486–0.883, respectively). However, Bland–Altman analysis revealed a mean difference of 1.6% between the methods within disease range with wide 95% limits of agreement (−16.7–19.8%). This interval even increased with exclusively considered vessel pairs of stenosis ≥1% (mean 5.3%; −24.1–34.7%) or symptomatic stenosis ≥50% (mean 0.1%; −25.7–26.0%).Conclusion: Our findings suggest that MPR-based diameter measurement and the semiautomated perpendicular area minimal caliber computation methods cannot be used interchangeably for the quantification of ICA steno-occlusive disease.

Feasibility of Ultra-High Resolution Supra-Aortic CT Angiography: An Assessment of Diagnostic Image Quality and Radiation Dose.

(1) Background: To evaluate diagnostic image quality and radiation exposure of ultra-high resolution cerebral Computed-Tomography (CT) angiography (CTA) obtained on an ultra-high resolution computed tomography scanner (UHR-CT). (2) Methods: Fifty consecutive patients with UHR-CTA were enrolled. Image reconstruction was processed with a 1024 × 1024 matrix and a slice thickness of 0.25 mm. Quantitative analyses comprising CT values, contrast–noise ratio (CNR) and signal-to-noise ratio (SNR) were performed. Subjective assessment of image quality, vessel contrast, noise, artefacts and delineation of different sized vessels were assessed by two readers on a 4-point scale. Radiation exposure was determined. (3) Results: Hounsfield values (ACI: 461.8 ± 16.8 HU; MCA: 406.1 ± 24.2 HU; BA: 412.2 ± 22.3 HU), SNR (ACI: 35.4 ± 13.1; MCA: 20.8 ± 12.4; BA: 23.7 ± 12.9) and CNR (ACI: 48.7 ± 21; MCA: 63.9 ± 26.9; BA: 48.1 ± 21.4) were remarkably high in all segments. Subjective analysis by two raters (fair agreement, k = 0.26) indicated excellent image qualities (image quality = 4; contrast = 4; noise = 3; artefacts = 4).Our analysis revealed a notably high traceability of the cerebral perforators (3 Points). Radiation exposure was at moderate dose levels (effective dose = 2.5 ± 0.6mSv). (4) Conclusions: UHR-CTA generates highly valuable image qualities that allow the depiction of vessels including cerebral perforators at acceptable dose levels. The UHR-CTA may therefore enhance the detection of small cerebral pathologies and may improve interpretability, especially in settings where high image qualities are crucial for the diagnostic accuracy.

Pre- and Post-stenting Cerebral Blood Flow Velocities in Patients with Carotid Artery Stenosis.

This study evaluated the hemodynamic effects of carotid artery stenting (CAS) on cerebral blood flow velocity (CBFV) in patients with carotid artery stenosis, before, 3 d, and 3 months after the procedure using transcranial Doppler ultrasound (TCD). The study included 36 patients with atheromatous carotid artery stenosis. Cerebral computed tomography (CT) or magnetic resonance imaging (MRI) was performed in every patient, and carotid stenosis was evaluated using duplex sonography, CT, and MRI angiography before the procedure. To obtain baseline values, the CBFV was evaluated 1 d before CAS. Follow-up TCD evaluations were performed 3 d and 3 months postoperatively. The median degree of internal carotid artery (ICA) stenosis in the participants was 90% (range 50%-99%). The median CBFV at the anterior cerebral artery (ACA) was significantly lower on the ipsilateral side than on the contralateral side before stenting; however, there were no significant differences in CBFV in the ipsi and contralateral middle cerebral artery (MCA). The median CBFV in the ipsilateral MCA increased significantly 3 d after the procedure and remained higher than the basal values after 3 months. We observed significant increases in the median CBFV and pulsatility index (PI) in the MCA bilaterally, especially on the stented side, measured 3 d and 3 months after stenting in patients with severe ICA stenosis.

Abstract 1122‐000021: Delayed Vasospasm and Cerebral Ischemia Following Mild Traumatic Brain Injury

Introduction : Post‐traumatic vasospasm (PTV) is a significant cause of morbidity and mortality following traumatic brain injury (TBI). 1 Delayed PTV is thought to occur due to inflammation from SAH. 1 The risk of symptomatic PTV is associated with the severity of TBI. 1,2,3 Treatment of PTV traditionally involves agents used in aneurysmal vasospasm such as Nimodipine. Intra‐arterial and intravenous verapamil and milrinone have been utilized to treat PTV. 4 We present a rare case of delayed cerebral ischemia caused by PTV without SAH treated with intra‐arterial milrinone and oral verapamil. Methods : This is a case report of a case of a 16‐day delay of cerebral ischemia secondary to PTV. Results : A 19‐year‐old female without significant medical history presented to the emergency room as the restrained driver in a motor vehicle collision involving a car versus a tree. The patient’s Glasgow Coma Scale score was 13 and the initial head CT did not demonstrate SAH with a Rotterdam score of 0. There were multiple fractures and soft tissue contusions noted on imaging which required surgical correction and splinting. The patient’s hospital stay was complicated by a large retroperitoneal hematoma requiring blood transfusions and surgical evacuation. 16 days after admission, the patient experienced sudden‐onset right upper extremity paralysis and weakness of the right leg. CT head demonstrated loss of gray‐white differentiation in the left middle cerebral artery (MCA) territory and CT angiography demonstrated 70% stenosis of the left supra‐clinoid internal carotid artery (ICA) and proximal left MCA. Cerebral angiography demonstrated 60% stenosis left supra‐clinoid ICA and 60% stenosis at the origin of the left MCA consistent with PTV. Left MCA stenosis improved to 20% post 10 mg intra‐arterial milrinone in the left ICA (Figure 1). The patient also received verapamil orally. Transcranial doppler demonstrated elevated peak systolic velocities at 298 cm/s in the left MCA and 276 cm/s in the left ICA. Six days later this improved to 150 cm/s in the left MCA and 151 cm/s in the left ICA. The patient continued to be unable to move her right side against gravity with dense expressive aphasia and dysarthria at discharge to inpatient rehabilitation. At follow‐up 4 weeks later, her right hemiparesis had improved significantly to being able to stand with assistance and her expressive aphasia had improved from one word to occasionally forming several word sentences. Conclusions : PTV is a potentially devastating complication of TBI. As our case demonstrates, the presence of mild TBI and absence of SAH may be falsely reassuring. 2 Additionally, our case report demonstrates that intra‐arterial milrinone causes radiographic improvement in PTV. Further studies are needed for the best screening and diagnostic exams for PTV and therapeutic interventions.

Assessment of Collaterals Using Multiphasic CT Angiography in Acute Stroke

The aim of the research was to compare the efficiency of multiphase and single-phase computed tomography (CT) angiography in assessing the leptomeningeal collaterals and in predicting the long-term clinical outcome as well as the risk of hemorrhagic transformation. A prospective study was conducted from October 2016 to May 2018 in consecutive patients who presented within 8 hours of the onset of acute anterior circulation ischemic strokes, with NIHSS (National Institutes of Health Stroke Scale) scores ≥5. They underwent triple-phase cerebral CT angiography, and the collaterals were assessed separately using both single-phase and multiphase techniques. The ability of the collaterals to predict the 24-hour CT ASPECTS (Alberta Stroke Program Early CT score), risk of cerebral hemorrhagic transformation, and 90-day clinical outcome was assessed. Fifty-six patients, which included 42 with an involvement of the middle cerebral artery and 14 with mixed occlusions, were assessed. In the multivariate logistic analysis, multiphase CT angiography collateral grading is one of the independent predictors of favorable outcomes. Area under the curve (AUC) was 0.853 (95% confidence interval [CI; 0.73, 0.97]) for multiphase CT collateral scoring in predicting the long-term functional independence, whereas single-phase CT (sCT) scoring displayed an AUC value of only 0.609 (95% CI [0.43, 0.78]). Eighty-two percent of the patients with good multiphase CT collaterals were functionally independent. CT ASPECTS at 24 hours was significantly better in patients with a good multiphase CT collateral score than in those with a good single-phase score. None of the patients with good collaterals in multiphase CT angiography had a significant hemorrhagic transformation. Good multiphase CT collaterals demonstrated 78% sensitivity, 81% specificity, and 80% accuracy in predicting the functional outcome. Multiphase CT collateral system was superior to single-phase angiography in predicting the long-term functional outcomes. Prediction of the hemorrhagic transformation risk was also observed to be better for multiphase CT.

Deep learning-based Hounsfield unit value measurement method for bolus tracking images in cerebral computed tomography angiography

BackgroundPatient movement during bolus tracking (BT) impairs the accuracy of Hounsfield unit (HU) measurements. This study assesses the accuracy of measuring HU values in the internal carotid artery (ICA) using an original deep learning (DL)-based method as compared with using the conventional region of interest (ROI) setting method. MethodA total of 722 BT images of 127 patients who underwent cerebral computed tomography angiography were selected retrospectively and divided into groups for training data, validation data, and test data. To segment the ICA using our proposed method, DL was performed using a convolutional neural network. The HU values in the ICA were obtained using our DL-based method and the ROI setting method. The ROI setting was performed with and without correcting for patient body movement (corrected ROI and settled ROI). We compared the proposed DL-based method with settled ROI to evaluate HU value differences from the corrected ROI, based on whether or not patients experienced involuntary movement during BT image acquisition. ResultsDifferences in HU values from the corrected ROI in the settled ROI and the proposed method were 23.8 ± 12.7 HU and 9.0 ± 6.4 HU in patients with body movement and 1.1 ± 1.6 HU and 3.9 ± 4.7 HU in patients without body movement, respectively. There were significant differences in both comparisons (P < 0.01). ConclusionDL-based method can improve the accuracy of HU value measurements for ICA in BT images with patient involuntary movement.

Relationship between cerebral aneurysms and variations in cerebral basal arterial network: a morphometric cross-sectional study in Computed Tomography Angiograms from a neurointerventional unit

ObjectiveSegments of cerebral basal arterial network (CBAN) dampen the peak pressure in blood flowing through these arteries, thus minimising the chances of development of cerebral aneurysms. The objective of this...

High-Resolution MRI to Evaluate Benefit of Middle Cerebral Artery Stenosis in Secondary Prevention in Patients with Acute Cerebral Infarction

High-resolution magnetic resonance (HRMRI) combined with magnetic resonance angiography (MRA) was used to analyze the correlation between the degree of infarction and the degree of cerebral vascular stenosis, and these patients are all have the trend to contain acute infarction. All patients were examined by CT cerebral angiography, which was analysed by conventional magnetic resonance imaging (MRI), high-Resolution (HRMRI) imaging, and cerebral vascular (MRA) imaging. The infarct size of each patient with cerebral infarction was calculated. The degree of middle cerebral artery stenosis was evaluated. Moreover, agnosis of acute cerebral infarction in middle cerebral artery region was calculated, and the correlation between acute cerebral infarction in middle cerebral artery region and the degree of cerebral vascular stenosis was analyzed. The specificity, sensitivity, and accuracy of magnetic resonance angiography (MRA) in the diagnosis of acute cerebral infarction in the blood supply area of the middle cerebral artery were 90.48%, 94.87%, and 93.94%. The coincidence rates for the degree of middle cerebral artery stenosis were 90.91% for mild stenosis, 92.31% for moderate stenosis, 93.75% for severe stenosis, and 85.71% for vascular occlusion, respectively. The K value was in good agreement with the results of CTA diagnosis (≥0.75). In conclusion, HRMRI can clearly indicated that the location of lesions with acute cerebral infarction, and MRA can show the degree of vascular stenosis, there is a close relationship between them.

Abstract P517: The Effect of Unfavorable Vascular Anatomy on Mechanical Thrombectomy for Middle Cerebral Artery Occlusion Strokes Preliminary Evaluation of the AIM2 Score System

Background: Time to reperfusion remains one of the strongest predictors of outcome in large vessel occlusion strokes (LVOS). Herein, we aim to assess the impact of unfavorable vascular anatomy on mechanical thrombectomy (MT) number of passes and procedural times. Methods: Retrospectively review of a prospective MT database spanning January-July 2018 including acute LVOS involving the middle cerebral artery-M1 segment and available baseline CT angiography. The AIM2 score (Table 1) was applied with patients categorized as favorable (AIM2: 0-2) versus unfavorable (AIM2: &gt;=3) anatomy. The primary outcome was the rate of &lt;3 device passes. Secondary outcomes included procedural times and the rates of successful reperfusion (mTICI2b-3) and 90-day mRS 0-2. Safety measures included rates of sICH and 90-day mortality. Results: Patients with unfavorable anatomy (n=15) were significantly younger (52±19, p=0.02) and had lower rates of hypertension (46% vs 80%, p=0.01) and smoking (0% vs 39%, p&lt;0.001) versus those with favorable anatomy (n=50). Successful reperfusion with &lt;3 passes was more often achieved with AIM2 scores 0-2 vs. ≥3 (84% vs 60%, p=0.04). There were no significant difference in other outcome measures (Table 2). Conclusions: The AIM2 score system represents a simple method for the systematically evaluation of vascular anatomy in MT and correlates significantly with increased number of MT passes.

Serebral Arteriyel Fenestrasyonların Sıklığının ve Serebral Anevrizma ile İlişkisinin BT Anjiografi ile Değerlendirilmesi

Objective: Fenestration is a vascular variation that begins with a common origin, then splits into two parallel luminal channels that rejoins distally. We aim to evalute the frequency of cerebral arterial fenestrations and their association with cerebral aneurysm by computed tomography (CT) angiography. Methods: We retrospectively analyzed cerebral CT angiography of patients obtained between January 2017 and December 2020. Patients older than 18 years-old, without known vascular disease and previous surgery or interventional treatment were included the study. The location of the fenestration and aneurysms were noted. Results: CT angiographies of 887 patients (mean age 54.8 years, range 18-63 years; 405 women and 482 men) were evaluated. 164 fenestrastions found in 152 patients for a detection rate of 17.1%. Anterior communicating artery fenestrations were the most common (51.2%), followed by vertebrobasilar system fenestration (28.7%). In our study, no significant relationship was found between fenestration and aneurysm, regardless of localization (p&gt;0.05). However, in the coexistence of fenestration and aneurysm, these are commonly located at the same localization (p: 0.005). Conclusion: Cerebral artery fenestration is an uncommon and mostly affects the anterior communicating artery and vertebrobasilar system. Cerebral artery fenestrations could be associated with aneurysms at the fenestration site. Further attention should be paid to the coexistence of aneurysm once intracranial artery fenestration has been found.

Invitation to participate in amulti-center study for validation of cerebral computed tomography angiography and computed tomography perfusion in the determination of cerebral circulatory arrest during brain death/death by neurological criteria diagnosis procedure in paediatric population below 12 years of age.

We would like to invite paediatric intensive care units (PICU) to join our multi-center trial concerning patient population < 12 y/o and aiming at: • validation of computed tomography angiography (CTA)/computed tomography perfusion (CTP) tests for brain death/death by neurological criteria (BD/DNC) diagnosis procedures, • validation of duplex Doppler insonation of extracranial segments of the internal cerebral arteries and the vertebral arteries for choosing an optimal time for CTA/CTP testing.

Quantifying asymmetry of anterior cerebral arteries as a predictor of anterior communicating artery complex aneurysm

ObjectivesThe aim of this study was to establish an anatomical index for early prediction of the risk of development of aneurysms in anterior communicating arterial complex (AcomAC). The asymmetric diameter...

Anatomical Variations in Circle of Willis in Patients Undergoing CT Cerebral Angiography in a Tertiary Hospital in Nepal: A Descriptive Cross-sectional Study.

Variation in Circle of Willis is a commonly encountered entity in patients undergoing computed tomography angiography, identification of which is crucial in the management of patients with vascular pathologies. The aim of the study was to find out the anatomical variations in the Circle of Willis in patients undergoing Computed Tomography cerebral angiography in a tertiary hospital in Nepal. This is a descriptive cross-sectional study involving 95 patients using convenient sampling techniques who were sent to the Department of Radiology and Imaging, Tribhuvan University Teaching hospital, for further evaluation of suspected vascular pathologies in the brain from April 2017 to September 2017. Ethical approval was taken from the Institutional Review Committee of the Institute of Medicine with reference number 326 (6-11-E). CT angiographic images of these patients were evaluated for the presence of variations in Circle of Willis, aneurysms, and other vascular pathologies. Data were analyzed using SPSS. Among 95 subjects included in the study, the anatomical variations in the arteries of Circle of Willis was seen in 52 (54.7%) patients, hypoplastic posterior communicating artery being the most common variation 33 (34.7%). The aneurysm was seen in 22 (23.2%) of cases. CT Angiography is a commonly performed imaging modality for suspected cases of cerebral aneurysms and various other vascular pathologies. Multidetector computed tomography can effectively detect variations in arteries of Circle of Willis, recognition of which is crucial in operative management of vascular pathologies.

The role of computed tomography angiogram in intracranial hemorrhage. Do the benefits justify the known risks in everyday practice?

BackgroundIntracranial hemorrhage is a commonly encountered medical problem frequently evaluated by computed tomography angiography (CTA). In CTA, there is radiation exposure and possible adverse effects of intravenous contrast administration. Therefore, the yield of this diagnostic tool needs to be explored in a heterogeneous group of daily encountered patients to provide insight into the risks and benefits of CTA. ObjectiveTo evaluate the role of cerebral CTA in patients with CT-confirmed or clinically suspected intracranial hemorrhage. MethodsThis retrospective study included all patients who underwent cerebral CTA for evaluation of intracranial hemorrhage that was diagnosed by a plain CT scan or suspected clinically from January 1, 2010, to May 30, 2018. All the scans were evaluated for abnormalities of the cerebral arteries in the CTA. ResultsOne hundred twenty patients were included, 74 % were males, and the mean age was 46 years. Approximately 18 % were trauma patients. Overall, CTA was abnormal in 52 % of cases, aneurysms were found in 27 %, and arteriovenous malformation (AVM) in 8 %. Among 82 patients who had a hemorrhage on the plain CT scans, 54 % had normal CTA, 28 % showed aneurysm, and 11 % showed AVM. In trauma patients, the most common CTA finding was normality (48 %), followed by aneurysms (19 %) and dissection (14 %). In non-trauma patients, the most common CTA finding was normality (49 %), followed by aneurysms (28 %) and AVM (10 %). ConclusionsCTA is a valuable diagnostic tool for intracranial hemorrhage because it detected abnormalities related to the hemorrhage in 42 % of patients. However, because more than half (58 %) of the patients had normal CTAs or showed CTA findings that were not relevant to the hemorrhage, clinical judgment should be exhausted before exposing them to radiation and intravenous contrast risks.