Diagnostic accuracy of CT angiography with matched mask bone elimination for detection of intracranial aneurysms: comparison with digital subtraction angiography and 3D rotational angiography

Comparison of bone subtraction CT angiography with standard CT angiography for evaluating circle of Willis in normal dogs

BACKGROUND

Bone subtraction computed tomography angiography (BSCTA) is a useful alternative technique for improving visualization of vessels surrounded by skull bone. However, no studies have compared computed tomography angiography (CTA) and BSCTA for improving the visibility of canine cerebral blood vessels.

OBJECTIVES

To evaluate the potential benefit of BSCTA for better delineation of brain arteries of the circle of Willis (CoW) in dogs by comparing BSCTA with non-subtraction computed tomography angiography (NSCTA).

METHODS

Brain CTA was performed for nine healthy beagle dogs using a bolus tracking method with saline flushing. A total dose of 600 mgI/kg of contrast agent with an iodine content of 370 mgI/mL was injected at a rate of 4 ml/s. Bone removal was achieved automatically by subtracting non-enhanced computed tomography (CT) data from contrast CT data. Five main intracranial arteries of the CoW were analyzed and graded on a scale of five for qualitative evaluation.

RESULTS

Scores of basilar artery, middle cerebral artery, and rostral cerebral artery in the BSCTA group were significantly higher than those in the NSCTA group (p = 0.001, p = 0.020, and p < 0.0001, respectively). Scores of rostral cerebellar artery (RcA) and caudal cerebral artery (CCA) did not differ significantly between the two groups. However, scores of RcA and CCA in the BSCTA group were higher than those in the NSCTA group.

CONCLUSIONS

BSCTA improved visualization of intracranial arteries of the CoW with close contact to bone. Thus, it should be recommended as a routine scan method in dogs suspected of having brain vessel disease.

Challenges in Managing Intractable Epistaxis in a Post-nasal Surgery and Radiated Cancer Patient: A Case Report and Literature Review

Recurrent epistaxis represents an alarming sign that may suggest a sinister aetiology, especially in patients with previous head and neck malignancy. The recognition of certain potentially life-threatening conditions, namely pseudoaneurysm or tumour recurrence, remains prudence to avoid disastrous repercussion. Nasal endoscopy has become an essential tool in otolaryngology. It can aid identify the underlying cause of epistasis and facilitate therapeutic management. On the other hand, radio imaging is highly sensitive in detecting vascular lesions, besides providing a pre-operative mapping if surgical intervention is planned. This paper reported a patient with sphenoidal sinus squamous cell carcinoma in remission presented with torrential epistaxis not relieved with nasal packing. Despite a repeated angiogram and magnetic resonance image, the identification of the source of bleeding remained futile, culminating in an examination under general anaesthesia. The diagnosis of carotid blowout syndrome was made intraoperatively, and the bleeding was temporarily secured with a muscular patch, preceded by the insertion of a vascular stent. The authors wish to highlight the importance of examination under general anaesthesia if radio imaging does not correlate to the clinical findings. Management options for carotid blowout should be tailored to the patients' medical conditions.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12070-023-03625-4.

The role of imaging in the management of non-traumatic subarachnoid hemorrhage: a practical review

The purpose of this review is to understand the role of imaging in the diagnosis and management of non-traumatic subarachnoid hemorrhage (SAH). SAH is a life-threatening emergency and a relatively common entity, the most common etiology being ruptured aneurysms. Multiple conundrums exist in literature at various steps of its imaging workup: diagnosis, management, and follow-up. We target our review to highlight the most effective practice and suggest efficient workup plans based on literature search, and describe in detail the clinical diagnostic and prognostic scales, role of CT scan, lumbar puncture, and MR, including angiography in the diagnosis and workup of SAH and its complications, and try to simplify the conundrums. Practical knowledge of imaging workup of SAH can help guide correct management of these patients, so as to reduce morbidity and mortality without resource overutilization.

Current imaging modalities for diagnosing cerebral vein thrombosis - A critical review

Cerebral vein thrombosis (CVT) is a rare presentation of venous thromboembolism. Prompt and accurate diagnosis is essential as delayed recognition and treatment may lead to permanent disability or even death. Since no validated diagnostic algorithms exist, the diagnosis of CVT mainly relies on neuroimaging. Digital subtraction angiography (DSA) is the historical diagnostic standard for CVT, but is rarely used nowadays and replaced by computed tomography (CT) and magnetic resonance imaging (MRI). High quality studies to evaluate the diagnostic test characteristics of state of the art imaging modalities are however unavailable to date. This review provides an overview of the best available evidence regarding the diagnostic performance of CT and MRI for the diagnosis of CVT. Notably, available studies are observational, mostly small, outdated, and with a high risk of bias. Therefore, direct comparison between studies is difficult due to large diversity in study design, imaging method, reference standard, patient selection and sample size. In general, contrast-enhanced techniques are more accurate for the diagnosis of CVT then non-contrast-enhanced techniques. CT venography and MRI have been both reported to be adequate for establishing a final diagnosis of CVT, but choice of modality as used in clinical practice depends on availability, local preference and experience, as well as patient characteristics. Our review underlines the need for high-quality diagnostic studies comparing CT venography and MRI in specific settings, to improve clinical care and standardize clinical trials.

Incidence, classification, and treatment of angiographically occult intracranial aneurysms found during microsurgical aneurysm clipping of known aneurysms

OBJECTIVE

During the microsurgical clipping of known aneurysms, angiographically occult (AO) aneurysms are sometimes found and treated simultaneously to prevent their growth and protect the patient from future rupture or reoperation. The authors analyzed the incidence, treatment, and outcomes associated with AO aneurysms to determine whether limited surgical exploration around the known aneurysm was safe and justified given the known limitations of diagnostic angiography.

METHODS

An AO aneurysm was defined as a saccular aneurysm detected using the operative microscope during dissection of a known aneurysm, and not detected on preoperative catheter angiography. A prospective database was retrospectively reviewed to identify patients with AO aneurysms treated microsurgically over a 20-year period.

RESULTS

One hundred fifteen AO aneurysms (4.0%) were identified during 2867 distinct craniotomies for aneurysm clipping. The most common locations for AO aneurysms were the middle cerebral artery (60 aneurysms, 54.1%) and the anterior cerebral artery (20 aneurysms, 18.0%). Fifty-six AO aneurysms (50.5%) were located on the same artery as the known saccular aneurysm. Most AO aneurysms (95.5%) were clipped and there was no attributed morbidity. The most common causes of failed angiographic detection were superimposition of a large aneurysm (type 1, 30.6%), a small aneurysm (type 2, 18.9%), or an adjacent normal artery (type 3, 36.9%). Multivariate analysis identified multiple known aneurysms (odds ratio [OR] 3.45, 95% confidence interval [CI] 2.16-5.49, p < 0.0001) and young age (OR 0.981, 95% CI 0.965-0.997, p = 0.0226) as independent predictors of AO aneurysms.

CONCLUSIONS

Meticulous inspection of common aneurysm sites within the surgical field will identify AO aneurysms during microsurgical dissection of another known aneurysm. Simultaneous identification and treatment of these additional undiagnosed aneurysms can spare patients later rupture or reoperation, particularly in those with multiple known aneurysms and a history of subarachnoid hemorrhage. Limited microsurgical exploration around a known aneurysm can be performed safely without additional morbidity.

Transvenous Embolization of Dural Arteriovenous Fistula of the Anterior Condylar Confluence via the Intercavernous Sinus Assisted by Bone Subtraction Computed Tomography Angiography

BACKGROUND

Dural arteriovenous fistulae (dAVFs) of the anatomically complex anterior condylar confluence (ACC) are often examined by computed tomography (CT) angiography and conventional angiography before treatment. Contrasted vessels often overlap with skull bones in enhanced CT scan and make it difficult to detect the shunt point of the dAVF. Bone subtraction CT angiography (BSCTA) can overcome this limitation and allow for superior imaging of dAVFs that may help to find an alternative access for catheterization.

CASE DESCRIPTION

An 80-year-old woman suffered from right ear tinnitus, headache, and an audible bruit. Preoperative imaging showed a dAVF of the ACC. It was fed by the bilateral ascending pharyngeal artery, drained to the internal jugular vein (IJV) via the inferior petrosal sinus, and had an intraosseous shunt pouch. We therefore performed transvenous embolization (TVE) via the intercavernous sinus because the angle between the anterior condylar vein and the IJV was too sharp to catheterize vessels through the ipsilateral IJV.

CONCLUSIONS

Understanding the inherently complex and individually unique venous anatomy of the ACC is crucial for treatment of dAVFs. BSCTA is an effective visualization technique for dAVFs of the ACC and allows for precise preoperative vascular structure evaluation. We suggest that in the case of the angle between the ACV and the IJV being too sharp to catheterize vessels through the ipsilateral IJV, TVE via the intercavernous sinus can be efficiently used.

A clinical study and meta-analysis of carotid stenosis with coexistent intracranial aneurysms

Carotid stenosis (CS) and intracranial aneurysms (IAs) may concur in one person. We studied the prevalence of IAs in CS patients in our retrospectively collected database and systematically reviewed this issue. Five hundred and fifty-seven CS (≥50%) patients confirmed by DSA in our hospital from 2010-06 to 2015-06 were screened for coexistent IAs. After searching the related literatures from English and Chinese journal literature databases, a meta-analysis was performed to pool the prevalence of CS with coexistent IAs. Subgroup analyses were performed to explore the causes of heterogeneity among studies. IAs were detected in 98(17.0%) out of the 577 CS patients. 12 literatures and the present study including a total of 6965 CS patients and 446 cases with coexistent IAs. The pooled prevalence of CS with coexistent IAs was 6.3% (95%CI: 4.2-8.3%) in all the CS patients. The pooled RR for female to male CS patients to have coexistent IAs was 1.67 (95%CI: 1.34-2.08, P = 0.000). 3 studies and the present study were carried out in Asian countries with a pooled prevalence of 10.8% (95%CI: 5.3-16.3%); 6 studies in European countries with 3.0% (95%CI: 2.2-3.7%); and 3 studies in USA with 6.0% (95%CI: 2.2-9.7%). There was a statistically significant difference between the three subgroups (P < 0.001). The prevalence of IAs in CS patients seems higher in our clinical study and the meta-analysis than in the general population and previously reported. The eastern and the women CS patients have a higher risk for coexistent IAs.

Current Perspectives in Imaging Modalities for the Assessment of Unruptured Intracranial Aneurysms: A Comparative Analysis and Review

BACKGROUND

Intracranial aneurysms (IAs) are pathologic dilatations of cerebral arteries. This systematic review summarizes and compares imaging techniques for assessing unruptured IAs (UIAs). This review also addresses their uses in different scopes of practice. Pathophysiologic mechanisms are reviewed to better understand the clinical usefulness of each imaging modality.

METHODS

A literature review was performed using PubMed with these search terms: "intracranial aneurysm," "cerebral aneurysm," "magnetic resonance angiography (MRA)," computed tomography angiography (CTA)," "catheter angiography," "digital subtraction angiography," "molecular imaging," "ferumoxytol," and "myeloperoxidase". Only studies in English were cited.

RESULTS

Since the development and improvement of noninvasive diagnostic imaging (computed tomography angiography and magnetic resonance angiography), many prospective studies and meta-analyses have compared these tests with gold standard digital subtraction angiography (DSA). Although computed tomography angiography and magnetic resonance angiography have lower detection rates for UIAs, they are vital in the treatment and follow-up of UIAs. The reduction in ionizing radiation and lack of endovascular instrumentation with these modalities provide benefits compared with DSA. Novel molecular imaging techniques to detect inflammation within the aneurysmal wall with the goal of stratifying risk based on level of inflammation are under investigation.

CONCLUSIONS

DSA remains the gold standard for preoperative planning and follow-up for patients with IA. Newer imaging modalities such as ferumoxytol-enhanced magnetic resonance imaging are emerging techniques that provide critical in vivo information about the inflammatory milieu within aneurysm walls. With further study, these techniques may provide aneurysm rupture risk and prediction models for individualized patient care.

Simulation study of Hemodynamic in Bifurcations for Cerebral Arteriovenous Malformation using Electrical Analogy

BACKGROUND AND OBJECTIVE

Cerebral Arteriovenous Malformation (CAVM) hemodynamic is disease condition, results changes in the flow and pressure level in cerebral blood vessels. Measuring flow and pressure without catheter intervention along the vessel is big challenge due to vessel bifurcations/complex bifurcations in Arteriovenous Malformation patients. The vessel geometry in CAVM patients are complex, composed of varying diameters, lengths, and bifurcations of various angles. The variations in the vessel diameter and bifurcation angle complicate the measurement and analysis of blood flow features invasively or non-invasively.

METHODS

In this paper, we proposed a lumped model for the bifurcation for symmetrical and asymmetrical networks in CAVM patients. The models are created using MATLAB Simulation software for various bifurcation angles. Each bifurcation angle created using electrical network- RLC. The segmentation and pre-processing of bifurcation vessels are implemented using adaptive segmentation. The proposed network address clinicians problem by measuring hemodynamic non-invasively. The method is applicable for any types of bifurcation networks with different bifurcation angles in CAVM patients.

RESULTS

In this work, we constructed a mathematical model, measured hemodynamic for 23 patients (actual and simulated cases) with 60 vessel bifurcation angles variations. The results indicate that comparisons evidenced highly significant correlations between values computed by the lumped model and simulated mechanical model for both networks with p < 0.0001. A P value of less than 0.05 considered statistically significant.

CONCLUSION

In this paper, we have modelled different bifurcation types and automatically display pressure and flow non-invasively at different node and at different angles of bifurcation in the complex vessel with help of bifurcation parameters, using lumped parameter model. We have simulated for different bifurcation angles and diameters of vessel for various imaging modality and model extend for different organs. This will help clinicians to measure haemodynamic parameters noninvasively at various bifurcations, where even catheter cannot be reached.

Interrater Agreement in the Radiologic Characterization of Ruptured Intracranial Aneurysms Based on Computed Tomography Angiography

OBJECTIVE

To determine interrater agreement in the initial radiologic characterization of ruptured intracranial aneurysms based on computed tomography angiography (CTA) with special emphasis on the rater's level of experience.

METHODS

One junior and one senior rater of 5 high-volume neurovascular tertiary centers evaluated anonymized CTA images of 30 consecutive patients with aneurysmal subarachnoid hemorrhage. Each rater described location, side, size, and morphology in a standardized manner. Interrater variability was analyzed using intraclass correlation and Fleiss' kappa analysis.

RESULTS

There was a high level of agreement for location (κ = 0.76, 95% confidence interval [CI] 0.74-0.79), side (κ = 0.95, CI 0.91-0.99), maximum diameter (intraclass correlation coefficient [ICC] 0.81, CI 0.70-0.90), and dome (ICC 0.78, CI 0.66-0.88) of intracranial aneurysms. In contrast, a lower level of agreement was observed for aneurysms' neck diameter (ICC 0.39, CI 0.28-0.58), the presence of multiple aneurysms (κ = 0.35, CI 0.30-0.40), and aneurysm morphology (blister κ = 0.11, CI -0.05 to 0.07; fusiform κ = 0.54, CI 0.48-0.60; multilobular, κ = 0.39 CI 0.33-0.45). The interrater agreement in the senior rater group was greater than in the junior rater group.

CONCLUSIONS

Interrater agreement confirms the benefit of CTA as initial diagnostic imaging in ruptured intracranial aneurysms but not for aneurysm morphology and presence of multiple aneurysms. A trend towards greater interrater agreement between more experienced raters was noticed.

Subtraction CT angiography for the detection of intracranial aneurysms: A meta-analysis

The aim of this meta-analysis was to investigate the accuracy of subtraction computed tomography angiography (CTA) for diagnosing intracranial aneurysms. A systematic literature search up to January 1, 2013 was performed in PubMed. Two independent reviewers selected 8 studies that compared subtraction CTA with digital subtraction angiography. Data from the studies were used to construct a 2×2 contingency table on a per-patient basis in ≥5 diseased and 5 non-diseased patients, with additional data on a per-aneurysm basis. Overall, subtraction CTA had a pooled sensitivity of 99% [95% confidence interval (CI), 95-100%] and specificity of 94% (95% CI, 86-97%) for detecting and ruling out cerebral aneurysms, respectively, on a per-patient basis. On a per-aneurysm basis, the pooled sensitivity was 96% (95% CI, 90-99%), and the specificity was 91% (95% CI, 85-95%). In conclusion, subtraction CTA is a highly sensitive, specific and non-invasive method for the diagnosis and evaluation of intracranial aneurysms.

Diagnostic Impact of Bone-Subtraction CT Angiography for Patients with Acute Subarachnoid Hemorrhage

BACKGROUND AND PURPOSE

Detection and evaluation of ruptured aneurysms is critical for choosing an appropriate endovascular or neurosurgical intervention. Our aim was to assess whether bone-subtraction CTA is capable of guiding treatment for cerebral aneurysms in patients with acute SAH and could replace DSA.

MATERIALS AND METHODS

We prospectively studied 116 consecutive patients with SAH with 16-detector row bone-subtraction CTA and DSA before intracranial aneurysm treatment. Two independent neuroradiologists reviewed the bone-subtraction CTA blinded to DSA (reference standard). We determined the accuracy of bone-subtraction CTA for aneurysm detection and the measurement of aneurysm dimensions and compared the radiation doses of the 2 imaging modalities.

RESULTS

Seventy-one patients (61%) had 74 aneurysms on DSA. Bone-subtraction CTA detected 73 of these aneurysms, but it detected 1 additional aneurysm. On a per-aneurysm basis, sensitivity, specificity, and positive and negative predictive values for bone-subtraction CTA were 99%, 98%, and 99% and 98%, respectively. For aneurysms of ≤3 mm, sensitivity was 94% (95% CI, 73%-99%). Bone-subtraction CTA slightly overestimated neck and dome diameters by <0.2 mm and overestimated the dome-to-neck ratios by 2% on average. Dose-length product was 565 ± 201 mGy × cm for bone-subtraction CTA and 1609 ± 1300 mGy × cm for DSA.

CONCLUSIONS

Bone-subtraction CTA is as accurate as DSA in detecting cerebral aneurysms after SAH, provides similar information about aneurysm configuration and measures, and reduces the average effective radiation dose for vascular diagnostics by 65%. Diagnostic equivalence in association with dose reduction suggests replacing DSA with bone-subtraction CTA in the diagnostic work-up of spontaneous SAH.

Spontaneous subarachnoid hemorrhage and negative initial vascular imaging--should further investigation depend upon the pattern of hemorrhage on the presenting CT?

BACKGROUND

Multiple investigations are usually performed in patients with spontaneous SAH who have negative initial angiography. This study aimed to evaluate the most appropriate use of additional imaging studies and how this may be influenced by the findings of the initial CT.

METHODS

A retrospective analysis was performed on a prospectively collected cohort of patients referred with spontaneous SAH and negative initial angiography. The patients were divided into four categories based upon the distribution of blood on the initial CT: perimesencephalic (pSAH), diffuse (dSAH), sulcal (sSAH) and CT negative (CSF positive for xanthochromia) (nCT-pLP). The number and nature of the subsequent imaging investigations were reviewed, and the results were correlated with the findings of the presenting CT.

RESULTS

One hundred fourteen patients were included in the study. Repeat imaging found five relevant abnormalities. Three cases of vasculitis were diagnosed on the first DSA following a negative CTA. A case of dissecting aneurysm was revealed on the third neurovascular study. A hemorrhagic spinal tumor presented with xanthochromia. No subsequent abnormality was found on the third DSA or MRI head. No case of pSAH had a subsequent positive finding if the initial CTA was negative.

CONCLUSIONS

Certain patterns of SAH are associated with a low yield of abnormalities on repeat imaging if the initial angiography is normal. The authors believe that the pattern of hemorrhage on the presenting CT should be used to guide the most appropriate use of further imaging modalities and present a diagnostic algorithm for this purpose.

3D bone subtraction CT angiography for the evaluation of intracranial aneurysms: a comparison study with 2D bone subtraction CT angiography and conventional non-subtracted CT angiography

BACKGROUND

Bone subtraction computed tomography angiography (BSCTA) is better able to facilitate the detection of intracranial aneurysms adjacent to bone structures compared to conventional non-subtracted CTA (CNSCTA). However, the comparison of the diagnostic accuracy of three-dimensional (3D) and two-dimensional (2D) BSCTA and conventional CTA in evaluating intracranial aneurysms remains unclear.

PURPOSE

To evaluate whether 3D BSCTA has a superior diagnostic accuracy to those of 2D BSCTA and CNSCTA in a single center with the same instrument.

MATERIAL AND METHODS

Sixty-three patients received 3D BSCTA, 2D BSCTA, and NSCTA for the detection and treatment planning of suspected intracranial aneurysms. The angiography readouts were reviewed by two independent radiologists. The sensitivity of CTA in detecting aneurysm was analyzed on a per-aneurysm and per-patient basis, using 3D digital subtraction angiography (DSA) and surgical findings as the gold standard. The potential of endovascular treatment or surgical clipping was also assessed based on information provided by the CTA.

RESULTS

A total of 66 aneurysms were detected in 54 patients. The overall sensitivity, specificity, positive, and negative predictive values of 3D BSCTA were all 100%, and these values for 2D BSCTA were 98.1%, 100%, 100%, and 90%, respectively. The total sensitivity, specificity, positive, and negative predictive values of CNSCTA were 94.4%, 100%, 100%, and 75%, respectively. Finally, 100%, 98.1%, and 85.2% patients received appropriate treatment decisions after 3D BSCTA, 2D BSCTA, and CNSCTA imaging, respectively.

CONCLUSION

3D BSCTA has a higher sensitivity for the detection of small aneurysms and aneurysms adjacent to bone compared to 2D BSCTA or CNSCTA, which were still able to obtain sufficient information for the detection of intracranial aneurysms and therapeutic decision-making.

Neuroimaging of headaches associated with vascular disorders

Headaches from vascular causes need to be differentiated from primary headaches because a misdiagnosis may lead to dire consequences for the patient. Neuroimaging is critical in identifying patients with vascular headaches and identifying the nature of the pathologic disorder causing these headaches. In addition, the imaging findings guide the physician regarding the optimal treatment modality for these lesions. This review summarizes the nuances of differentiating patients with secondary headaches related to vascular disease and discusses pertinent neuroimaging studies.

Dual-Energy CT: What the Neuroradiologist Should Know

Because of the different attenuations of tissues at different energy levels, dual-energy CT offers tissue differentiation and characterization, reduction of artifacts, and remodeling of contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR), hereby creating new opportunities and insights in CT imaging. The applications for dual-energy imaging in neuroradiology are various and still expanding. Automated bone removal is used in CT angiography and CT venography of the intracranial vessels. Monoenergetic reconstructions can be used in patients with or without metal implants in the brain and spine to reduce artifacts, improve CNR and SNR, or to improve iodine conspicuity. Differentiation of iodine and hemorrhage is used in high-density lesions, after intra-arterial recanalization in stroke patients or after administration of contrast media. Detection of underlying (vascular and non-vascular) pathology and spot sign can be used in patients presenting with (acute) intracranial hemorrhage.

Clinical practice guideline for the management of intracranial aneurysms

Purpose

An intracranial aneurysm, with or without subarachnoid hemorrhage (SAH), is a relevant health problem. The rupture of an intracranial aneurysm is a critical concern for individual health; even an unruptured intracranial aneurysm is an anxious condition for the individual. The aim of this guideline is to present current and comprehensive recommendations for the management of intracranial aneurysms, with or without rupture.

Materials and Methods

We performed an extensive literature search, using Medline. We met in person to discuss recommendations. This document is reviewed by the Task Force Team of the Korean Society of Interventional Neuroradiology (KSIN).

Results

We divided the current guideline for ruptured intracranial aneurysms (RIAs) and unruptured intracranial aneurysms (UIAs). The guideline for RIAs focuses on diagnosis and treatment. And the guideline for UIAs focuses on the definition of a high-risk patient, screening, principle for treatment and selection of treatment method.

Conclusion

This guideline provides practical, evidence-based advice for the management of patients with an intracranial aneurysm, with or without rupture.

Iatrogenic traumatic intracranial aneurysm after endoscopic sinus surgery

Iatrogenic traumatic intracranial aneurysms are rare, but their clinical impact is significant secondary to their risk of intracranial hemorrhage and in their frequent complexity in management. We report an adult patient with a history of chronic sinusitis who, while undergoing elective endoscopic polypectomy, suffered an iatrogenic injury to an A2 segment branch of the left anterior cerebral artery, resulting in a pseudoaneurysm. Management included endovascular coiling and a bicoronal craniotomy approach, using a split-thickness cranial graft and abdominal fat graft to repair the associated left cribriform plate defect.

The role of bone subtraction computed tomographic angiography in determining intracranial aneurysms in non-traumatic subarachnoid hemorrhage

Background:

The presence of blood in the subarachnoid space is an acute pathology with a serious risk of death and complications. The most common etiology (approximately 80%) is intracranial aneurysm.

Objectives:

The aim of this study was to assess the role of bone subtracted computed tomographic angiography (BSCTA), a novel and noninvasive method for determining and characterizing intracranial aneurysms.

Patients and Methods:

Sixty consecutive patients with clinically suspected non-traumatic subarachnoid hemorrhage (SAH) were considered to enter the study. The subtraction quality was inadequate in ten patients; thus, they were excluded, leaving 50 patients (84.4%) in the study. Bone subtracted and non-subtracted 3D images were obtained from the BSCTA raw data sets. All images obtained by digital subtraction angiography (DSA), BSCTA, and computed tomographic angiography (CTA) were evaluated for the presence or absence of an aneurysm and the location, minimal sac diameter, and neck size ratio of the aneurysm. DSA was considered as the gold standard during the evaluation of the data.

Results:

Of the 50 patients who participated in this study, 11 had no aneurysms as determined by both CTA and DSA. Examination of the remaining 39 patients revealed the presence of 51 aneurysms. While 3D-CTA could not detect six aneurysms that were located in the base of the skull, 3D-BSCTA easily detected them. Moreover, five aneurysms were only partially detected by 3D-CTA. According to this data, the sensitivity of 3D-BSCTA and 3D-CTA was calculated as 98% and 86.3%, respectively; the specificity was calculated as 100% and 90.9%, respectively, per aneurysm; and the sensitivity of 100% for 3D-BSCTA and 98% for 3D-CTA was achieved by using combined images with multi-planar reconstruction (MPR) and maximum intensity projection (MIP). BSCTA detected and characterized the aneurysms as well as DSA, and BSCTA and DSA gave concordant results in detecting aneurysms.

Conclusions:

BSCTA is easily accessible, less time consuming, and most importantly, a non-invasive technique for detecting intracranial aneurysms. It is also suitable for patients who have been referred to emergency services. Therefore, it can be used in emergency conditions and as a first-line diagnostic method in patients with non-traumatic SAH.

Utility of 320-detector row CT for diagnosis and therapeutic strategy for paraclinoid and intracavernous aneurysms

BACKGROUND

The aim of this study was (1) to assess the diagnostic accuracy of 320-detector row computed tomography (CT) for paraclinoid and intracavernous aneurysms, and (2) to investigate whether this method provides sufficient information for surgery.

METHODS

A total of 14 patients with 16 unruptured proximal ICA aneurysms underwent three-dimensional CT angiography (3D-CTA) fusion imaging, which was created by superimposing 3D-CT venography data and/or 3D-bone data onto 3D-CTA data using 320-detector row CT, magnetic resonance imaging (MRI), and 3D digital subtraction angiography (DSA). The images of each modality were assessed using intraoperative findings as the reference standard.

RESULTS

All aneurysms were clearly visualized on 320-detector row CT. Bone subtraction and arterio-venous discrimination were accurate. On 3D-CTA fusion images, 11 aneurysms were diagnosed as "extracavernous" and five as "intracavernous". No discordance in aneurysm location between the 3D-CTA fusion images and the intraoperative findings was found. In contrast, discordance between MRI and intraoperative findings were found in five of the 16 cases (31%), which was significantly more frequent than with 3D-CTA (p = 0.043). The findings DSA, which was performed in nine patients, were also in excellent agreement with the intraoperative findings. However, 3D-CTA fusion imaging provided more comprehensive information, including venous and osseous structures, than 3D-DSA. The 320-detector row CTA after surgery demonstrated a clear relationship between the clip and aneurysmal neck with notably few artifacts, which suggested the utility of this modality for postoperative assessment.

CONCLUSIONS

The 320-detector row CT provided high accuracy for the diagnosis of paraclinoid and intracavernous aneurysms. This technique also provided comprehensive depiction of the aneurysms and surrounding structures. Therefore, this modality might be useful for the diagnosis of the paraclinoid and intracavernous aneurysms and for developing a surgical treatment plan.

Vascular pathology in the extracranial vertebral arteries in patients with acute ischemic stroke

Introduction

Vascular pathology in the extracranial vertebral arteries remains among the possible causes in cryptogenic stroke. However, the diagnosis is challenged by the great variety in the anatomy of the vertebral arteries, clinical symptoms and difficulties in the radiological assessments. The aim of this study was to assess the prevalence of CT angiography (CTA)-detected pathological findings in the extracranial vertebral arteries in an acute stroke population and secondly to determine the frequency of posterior pathology as probable cause in patients with otherwise cryptogenic stroke.

Method

The analysis was based on 657 consecutive patients with symptoms of acute stroke and a final diagnosis of ischemic stroke or transient ischemic attack. On admission, a noncontrast CT cerebrum and CTA were performed. A senior consultant neuroradiologist, blinded to clinical data, reviewed all CTA scans systematically, assessing the four segments of the extracranial vertebral arteries. First, the frequency of pathological findings including stenosis, plaques, dissection, kinked artery and coiling was assessed. Subsequently, we explored the extent of the pathological findings that were the most plausible causes of stroke, namely either a possible dissection or a kinked artery.

Results

Findings in the extracranial vertebral arteries included significant stenosis (0.8%), atherosclerotic plaque types (3.8%), possible dissections (2.6%), kinked arteries (2.6%) and coiling (32.0%). Eighteen patients (2.8%) with pathological findings had an unknown cause of stroke, likely posterior symptoms and no clinical stroke symptoms from the anterior circuit. Of these, 3 cases were kinked arteries (0.5%) and 15 cases (2.3%) were possible dissections.

Conclusion

We found that in approximately 3% of the study population, the most plausible cause of the cryptogenic strokes was due to a pathological finding in the posterior extracranial vertebral arteries, being either a possible dissection or a kinked artery. In general, posterior vascular pathology is not uncommon, and CTA is a useful modality in the detection of changes based on characteristics and locations of findings in the extracranial vertebral arteries. Ultrasound examination can be a useful supplementary tool in deciding the consequence of vascular findings on CTA.

Benefit of a Sharp Computed Tomography Angiography Reconstruction Kernel for Improved Characterization of Intracranial Aneurysms

BACKGROUND:

Computed tomography angiography (CTA) is the first-line imaging modality used for cerebral aneurysms because of its speed and sensitivity for detection, although digital subtraction angiography is often required for more detailed aneurysm shape delineation.

OBJECTIVE:

To determine whether a sharper CTA reconstruction kernel can better characterize an aneurysm and improve decision-making before intervention.

METHODS:

Fifteen patients presenting with aneurysmal subarachnoid hemorrhage underwent 64-row CTA. CTA data were reconstructed using the default H20f smooth kernel and a H60f sharp kernel and compared with contemporaneous catheter 3-dimensional rotational angiography (3DRA). Aneurysm neck, width, and aspect ratio measurements were made using intensity line plots of identical projections on all imaging datasets and compared by matched-pair statistics.

RESULTS:

Aneurysm neck measurements from the H20f smooth kernel revealed overestimation compared with both the sharp kernel (greater by 0.64 ± 0.21 mm, P &lt; .01) and 3DRA (greater by 0.68 ± 0.19 mm, P &lt; .01). There was no statistically significant difference between 3DRA and the sharp kernel CTA measurements. Neck measurements correlated well between the H60f kernel and 3DRA but not between the H20f Kernel and 3DRA (R 0.97 vs 0.86).

CONCLUSION:

H60f sharp CTA kernel reconstruction provides more accurate anatomic characterization of cerebral aneurysms than the H20f smooth kernel at the expense of less visually pleasing reconstructions. Because it does not require additional contrast, radiation, or imaging hardware and is more similar to 3DRA, it may aid in selecting the appropriate treatment strategy before to evaluation by catheter-based angiography.

Automated subtraction CT angiography for visualization of the whole brain vasculature: a feasibility study

RATIONALE AND OBJECTIVES

To develop an automated computed tomography angiography (CTA) imaging protocol that allows visualization of the whole brain vasculature and evaluate the clinical usefulness of the technique for delineation of intracranial vessels in patients with cerebrovascular disorders.

MATERIALS AND METHODS

We prospectively included 100 patients who underwent automated subtraction CTA for suspected cerebrovascular disorders. The nonenhanced and contrast enhanced scans were obtained with the same table feeding speed. The x-ray tube start angles of the two scans were matched to enable accurate registration and subtraction of the CTA datasets. Subtracted CTA datasets were reformatted as three-dimensional volume rendering and maximum intensity projection images for further review. Two independent readers assessed the quality of subtraction and delineation of intracranial vessels. The visibility of ophthalmic arteries was also assessed.

RESULTS

Subtraction was successful in all patients. The image quality of bone removal was rated excellent in 95 patients, with no or minimal bone remnants. Incomplete bone removal was observed in five patients because of severe motions between the scans. In 97 of 100 patients, arterial segments at the circle of Willis could be clearly visualized. Excellent delineation of bilateral ophthalmic arteries was possible in 81 of 100 patients.

CONCLUSIONS

The whole brain vasculature would be clearly visualized by using the optimized automated CTA protocol. Our automated, single-source, dual-energy subtraction CTA protocol is a fully automated subtraction method that is capable of delineating major intracranial vessels as well as very small arteries.

Update on the management of subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) is a devastating cerebrovascular disease. Outcome after SAH is mainly determined by the initial severity of the hemorrhage. Neuroimaging, in particular computed tomography, and aneurysm repair techniques, such as coiling and clipping, as well as neurocritical care management, have improved during the last few years. The management of a patient with SAH should have an interdisciplinary approach with case discussions between the neurointensivist, interventionalist and the neurosurgeon. The patient should be treated in a specialized neurointensive care unit of a center with sufficient SAH case volume. Poor-grade patients can be observed for complications and delayed cerebral ischemia through continuous monitoring techniques in addition to transcranial Doppler ultrasonography such as continuous electroencephalography, brain tissue oxygenation, cerebral metabolism, cerebral blood flow and serial vascular imaging. Neurocritical care should focus on neuromonitoring for delayed cerebral ischemia, management of hydrocephalus, seizures and intracranial hypertension, as well as of medical complications such as hyperglycemia, fever and anemia.

Prevalence of asymptomatic incidental aneurysms: a review of 2,685 computed tomographic angiograms

OBJECTIVE

Intracranial aneurysms are a public health issue with a potential for rupturing, causing significant morbidity/mortality. The prevalence of unruptured intracranial aneurysms, including those that are asymptomatic, varies widely, as it has been determined through autopsy studies as well as conventional angiography. However, computed tomography angiography, a less invasive procedure, has replaced the use of conventional angiography in the recent decades. The objective of the present study is to determine the prevalence of incidental aneurysms.

METHODS

The present study reviews all computed tomography angiography cases within the past decade at a single institution.

RESULTS

Of 2195 cases included in the study, 39 (1.8%) were found to have asymptomatic unruptured aneurysms.

CONCLUSIONS

The numbers of asymptomatic incidental aneurysms have increased.

Dual-energy CT of the brain and intracranial vessels

OBJECTIVE

The purpose of this review is to summarize the principles and applications of dual-energy CT in evaluation of the brain and the intracranial blood vessels.

CONCLUSION

One major advantage of dual-energy CT is the capability of material differentiation. In general, this property can be applied to bone removal in CT angiography for easier and faster postprocessing. In neuroradiology, material decomposition allows detection of hemorrhage on contrast-enhanced CT scans and facilitates the search for the underlying pathologic mechanism of hematomas. The combination of low radiation dose and advantageous spectral information (blood vs contrast) from these datasets justifies broad clinical implementation of dual-energy CT in neuroradiology.

Coiling of ruptured tiny cerebral aneurysms, feasibility, safety, and durability at midterm follow-up, and individual experience

BACKGROUND AND PURPOSE

The tiny size of cerebral aneurysms represents one of the challenging facets for endovascular treatment, with a high risk for intraoperative rupture (IOR). We report on the treatment of tiny ruptured saccular cerebral aneurysms by coil embolization. All cases were that of £ 2-3 mm aneurysms with at least one of the dimensions < 2 mm.

MATERIALS AND METHODS

Between April 2008 and December 2010, we performed a retrospective analysis of nine consecutive cases of tiny aneurysms treated by coil embolization in our institution.

RESULTS

Coil embolization was successfully performed in nine cases, whereas in one case, intraoperative rupture (IOR) of the fundus was encountered before complete obliteration of the aneurysm expected to be achieved with two coils. Complete occlusion (in n = 7 aneurysms) or near-complete immediate occlusion (in n = 2 aneurysms) was achieved. A total of 18 coils was used for coiling of the nine aneurysms, wherein five aneurysms were coiled with two coils each, two aneurysms with three coils each, and two aneurysms with only one coil each to achieve accepted results. Balloon assistance was used in three cases. Although a minimal coil projection in the parent vessel was seen in three cases, no untoward clinical complications were seen. At mean follow-up (6.7 months, interquartile range (IQR) 3-12 months), digital subtraction angiography (DSA) and magnetic resonance angiography (MRA) in nine patients demonstrated persistent complete occlusion in six of the aneurysms; one aneurysm showed marked filling of the fundus, and two showed neck remnant but did not need retreatment. All patients with available follow-up were independent in day-to-day activities with a modified Rankin score (mRS) of 0 or 1.

CONCLUSIONS

Coil embolization of tiny ruptured cerebral aneurysms is feasible. Careful consideration of the technical issues in treatment of such aneurysms is essential to achieve technical success while avoiding complications.

320-detector row CT angiography for detection and evaluation of intracranial aneurysms: comparison with conventional digital subtraction angiography

AIM

To compare the diagnostic performance of 320-detector row computed tomographic angiography (CTA) with digital subtraction angiography (DSA) for the detection and characterization of intracranial aneurysms.

MATERIALS AND METHODS

Fifty-two consecutive patients with non-traumatic subarachnoid haemorrhage (SAH) and suspected intracranial aneurysms were evaluated from January 2009 to October 2011. All underwent both 320-detector row volume CTA examination and DSA. CTA volume data were transmitted to a VITREA workstation and two physicians with experience in diagnostic imaging of the nervous system independently carried out image post-processing and assessed the results. The three-dimensional (3D) CTA and DSA images were assessed using intraoperative findings as the reference standard.

RESULTS

In 52 patients, 54 aneurysms were detected; 48 patients underwent surgery for 50 aneurysms. The overall sensitivity, specificity, and accuracy of 3D CTA were 96.3, 100, and 94.6%, respectively. Meanwhile, the overall sensitivity, specificity, and accuracy of DSA were 98.1, 98.1, and 95.1%, respectively. For aneurysms less than 3 mm, the sensitivity, specificity, and accuracy of 3D CTA were 81.8, 100, and 93.3%, respectively. The sensitivity, specificity, and accuracy of DSA for small aneurysms were 90.9, 100, and 96.2%, respectively. 3D CTA was superior to DSA in demonstrating aneurysmal calcification, parent artery, and surrounding vascular anatomy.

CONCLUSIONS

3D CTA is a highly sensitive, specific, and non-invasive imaging method for diagnosis and evaluation of intracranial aneurysms. It also allows for precise depiction of aneurysm morphology. Therefore, 320-detector row CTA may be used as an alternative to DSA as a first-line imaging technique in patients with SAH.

The current status and recent advances in high-resolution imaging of spinal vascular malformations

The management of spinal vascular malformations (SVM) has improved over the last four decades with the evolution of imaging, anesthesia, microsurgery, and endovascular techniques. Commonly used high-resolution imaging techniques include CT angiography, magnetic resonance angiography, and digital subtraction angiography. We review the advances that have been made in these imaging modalities and discuss their present role for imaging SVM, with the goal of assisting neurosurgeons in making judicious use of current imaging techniques to develop the most effective management strategies for these complex lesions.

Guidelines for the management of aneurysmal subarachnoid hemorrhage: a guideline for healthcare professionals from the American Heart Association/american Stroke Association

PURPOSE

The aim of this guideline is to present current and comprehensive recommendations for the diagnosis and treatment of aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

A formal literature search of MEDLINE (November 1, 2006, through May 1, 2010) was performed. Data were synthesized with the use of evidence tables. Writing group members met by teleconference to discuss data-derived recommendations. The American Heart Association Stroke Council's Levels of Evidence grading algorithm was used to grade each recommendation. The guideline draft was reviewed by 7 expert peer reviewers and by the members of the Stroke Council Leadership and Manuscript Oversight Committees. It is intended that this guideline be fully updated every 3 years.

RESULTS

Evidence-based guidelines are presented for the care of patients presenting with aSAH. The focus of the guideline was subdivided into incidence, risk factors, prevention, natural history and outcome, diagnosis, prevention of rebleeding, surgical and endovascular repair of ruptured aneurysms, systems of care, anesthetic management during repair, management of vasospasm and delayed cerebral ischemia, management of hydrocephalus, management of seizures, and management of medical complications.

CONCLUSIONS

aSAH is a serious medical condition in which outcome can be dramatically impacted by early, aggressive, expert care. The guidelines offer a framework for goal-directed treatment of the patient with aSAH.

Cerebrovascular geometry in the anterior circulation: an analysis of diameter, length and the vessel taper

BACKGROUND

A study was undertaken to determine the typical length, diameter and taper of vessels in the anterior cerebral circulation.

METHODS

The sample size was calculated at 100 patients based on similar measurements in the literature and divided into cohorts based on gender and side. These patients were consecutively collected from a population that had undergone CT angiography and did not have any vascular abnormality. The arterial diameter was measured at the proximal cavernous internal carotid artery (ICA), the ICA terminus, the middle cerebral artery (MCA) origin and an M2 origin. The length between these endpoints was calculated along the center line. The vessel taper was calculated for the ICA as the change in caliber per unit length.

RESULTS

The mean length of the ICA from the proximal cavernous segment to the ICA terminus was 33.1 ± 6.1 mm. The mean diameter at the cavernous ICA and the ICA terminus was 5 ± 0.6 mm and 3.6 ± 0.4 mm, respectively. The mean ICA taper was 0.04 ± 0.02 mm/1 mm. For the MCA, the diameter at the MCA and M2 origins measured 3.1 ± 0.4 mm and 2.4 ± 0.4 mm, respectively. The mean MCA length was 22.5 ± 8.1 mm. There was no significant difference based on gender or between right and left sides. Patients aged >60 years had longer ICAs (p=0.02), larger cavernous ICA (p=0.003), ICA terminus (p<0.0001) and MCA origin (p=0.01) diameters than those aged 40-60 years. The ICA vessel taper did not change with age.

CONCLUSION

ICA and MCA vessel size did not change based on gender or side. Older patients had more redundant vessels based on diameter and length. The ICA has a gentle taper from its proximal cavernous segment to the ICA terminus. This information can be important in planning interventions or designing endovascular devices.

Angiographic CT with intravenous contrast injection compared with conventional rotational angiography in the diagnostic work-up of cerebral aneurysms

BACKGROUND AND PURPOSE

Noninvasive imaging of cerebral aneurysms is still considered inferior to conventional angiography. The purpose of this study was to evaluate the diagnostic accuracy of ivACT in the assessment of intracranial aneurysms compared with 3D-DSA.

MATERIALS AND METHODS

We included 13 patients with 15 incidental unruptured saccular aneurysms scheduled for diagnostic angiographic work-up in our study. In each patient, we performed an ivACT and a conventional angiography including a 3D rotational run. During postprocessing, MPR images were generated for each technique. Maximal aneurysm diameter, neck diameter, aneurysm height, maximum width, bulge height, parent artery diameter, and angle between the parent artery and aneurysm apex were measured for each aneurysm.

RESULTS

3D-DSA and ivACT both provided images of high quality without artificial disturbances (ie, motion artifacts). Measurements of all parameters resulted in comparable values for both modalities with a strong correlation (P ≤ .001).

CONCLUSIONS

ivACT is feasible for the noninvasive visualization of saccular cerebral aneurysms and may provide reliable diagnostic information for the assessment of aneurysm size and geometry comparable with conventional intra-arterial 3D rotational angiography. These preliminary results might be a first promising step to replacing conventional angiography in preinterventional aneurysm imaging.