Detection Of Intracranial Aneurysms Research Articles

Comparison of 64 Dedector Cranial CT Angiography with Intra-Arterial DSA For Detection of Intracranial Aneurysms

The purpose of our study was to compare findings of 64 detector cranial computed tomographic angiography (CTA) and convention al digital subtraction angiography (DSA) mainly in patients with acute subarachnoid hemorrhage (SAH) headache and diplopia. Between March 2007 and May 2009, 65 consecutive patients were admitted with clinical symptoms and signs of intracranial aneurysm. 44 of 67 detected aneurysms were confirmed during surgery or endovascular embolization. DSA was performed in the 3 days after CTA. CT angiograms and conventional angiographies were studied by two radiologists, who performed aneurysm detection and characterisation of morphological features. Using CTA and DSA, we detected 67 aneurysms in 50 patients. 15 patients did not have any aneurysms in both DSA and CTA. There was no difference between the two modalities in the number of the detected aneurysms. But two aneurysms were falsely located before surgery with CTA. They were located in posterior communicating artery (PcoA) but, had been thought to be located at the internal carotid artery supraclinoid segment at CTA. CTA has an equal sensitivity as DSA in the detection of intracranial aneurysms. It has 100% detection rate in anterior communicating artery and middle cerebral artery bifurcation aneurysms, but aneurysms at some locations, like the ones at PcoA, were hard to detect with CTA. DSA preserves its diagnostic value for detection of posterior circulation aneurysms.

Computer-aided diagnosis improves detection of small intracranial aneurysms on MRA in a clinical setting.

MRA is widely accepted as a noninvasive diagnostic tool for the detection of intracranial aneurysms, but detection is still a challenging task with rather low detection rates. Our aim was to examine the performance of a computer-aided diagnosis algorithm for detecting intracranial aneurysms on MRA in a clinical setting. Aneurysm detectability was evaluated retrospectively in 48 subjects with and without computer-aided diagnosis by 6 readers using a clinical 3D viewing system. Aneurysms ranged from 1.1 to 6.0 mm (mean = 3.12 mm, median = 2.50 mm). We conducted a multireader, multicase, double-crossover design, free-response, observer-performance study on sets of images from different MRA scanners by using DSA as the reference standard. Jackknife alternative free-response operating characteristic curve analysis with the figure of merit was used. For all readers combined, the mean figure of merit improved from 0.655 to 0.759, indicating a change in the figure of merit attributable to computer-aided diagnosis of 0.10 (95% CI, 0.03-0.18), which was statistically significant (F(1,47) = 7.00, P = .011). Five of the 6 radiologists had improved performance with computer-aided diagnosis, primarily due to increased sensitivity. In conditions similar to clinical practice, using computer-aided diagnosis significantly improved radiologists' detection of intracranial DSA-confirmed aneurysms of ≤6 mm.

Low tube voltage and low contrast material volume cerebral CT angiography.

To evaluate the image quality, radiation dose and diagnostic accuracy of low kVp and low contrast material volume cerebral CT angiography (CTA) in intracranial aneurysm detection. One hundred twenty patients were randomly divided into three groups (n = 40 for each): Group A, 70 ml iodinated contrast agent/120 kVp; group B, 30 ml/100 kVp; group C, 30 ml/80 kVp. The CT numbers, noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were measured in the internal carotid artery (ICA) and middle cerebral artery (MCA). Subjective image quality was evaluated. For patients undergoing DSA, diagnostic accuracy of CTA was calculated with DSA as reference standard and compared. CT numbers of ICA and MCA were higher in groups B and C than in group A (P < 0.01). SNR and CNR in groups A and B were higher than in group C (both P < 0.05). There was no difference in subjective image quality among the three groups (P = 0.939). Diagnostic accuracy for aneurysm detection among these groups had no statistical difference (P = 1.00). Compared with group A, the radiation dose of groups B and C was decreased by 45% and 74%. Cerebral CTA at 100 or 80 kVp using 30 ml contrast agent can obtain diagnostic image quality with a low radiation dose while maintaining the same diagnostic accuracy for aneurysm detection. • Cerebral CTA is feasible using 100/80 kVp and 30 ml contrast agent. • This approach obtains diagnostic image quality with 45-74% radiation dose reduction. • Diagnostic accuracy for intracranial aneurysm detection seems not to be compromised.

Detection and Evaluation of Intracranial Aneurysms with 3D-CT Angiography and Compatibility of Simulation View with Surgical Observation.

The aim of this study was to report our experience with a 64-channel computerized tomography (CT) scanner as the primary choice on the detection of intracranial aneurysms. Comparison of intracranial aneurysms with the simulated images obtained via three-dimensional computed tomography angiography (3D-CTA) in pterional approach was also aimed. Among 288 consecutive patients who had intracranial aneurysms detected on 64-slice CTA, a total of 337 aneurysms were detected. CTA simulation images and intraoperative images were compared with regards to size, shape, and orientation. In one of the 22 CTA-negative cases, one aneurysm was detected in DSA and an additional aneurysm was detected in a patient operated with CTA. Aneurysm size, shape and direction were error free except a few cases. However, CTA was found to be insufficient to show particularly perforating arteries that were smaller than 2 mm in size. As a fast and noninvasive technique, CTA can be used as an initial examination in subarachnoid hemorrhage. Keeping the fact that there can be insufficiency in showing particularly small aneurysms in mind, DSA should be performed on CTA-negative cases and required cases.

Long-term behavioral and cognitive outcomes following clipping for incidental unruptured intracranial aneurysms.

Recent advances in neuroimaging techniques have resulted in more frequent detection of unruptured intracranial aneurysms. Regardless of the method employed, most interventions to treat lesions have low morbidity and mortality rates. Recently, some studies have suggested that changes in cognitive status are one complication of microsurgical treatments. However, no study to date has performed any behavioral analysis. Moreover, cognitive assessment beyond 12 months after surgical intervention is missing. The current study sought to evaluate the long-term impact of clipping on the behavioral and cognitive functions of patients with unruptured intracranial aneurysms. A within-subjects prospective clinical trial was performed to evaluate 40 patients who underwent microsurgical clipping for incidental unruptured intracranial aneurysms. The participants underwent a full neuropsychological evaluation during the preoperative period, at 3 months after surgery and at 3 years after surgery. Paired Student's t tests and an ANOVA, followed by a Bonferroni post hoc test, were used to examine group differences. The cognitive and behavioral test performance of the patients did not deteriorate during either the short or the long term following intervention. Moreover, the patients' clinical and demographic characteristics did not predict behavioral or cognitive changes, and neither the surgical approach nor the topography, multiplicity, or size of the aneurysms affected the results. In either the short or the long term following clipping for patients with incidental unruptured intracranial aneurysms, behavioral and cognitive functions had no significant change from baseline. The intervention demonstrated high efficacy and was associated with a low morbidity rate.

Diagnosing Intracranial Aneurysms With MR Angiography

The aim of this study was to evaluate the sensitivity and specificity of MR angiography (MRA) in the diagnosis of ruptured and unruptured intracranial aneurysms. A systematic search was performed on 4 electronic databases on relevant articles that were published from January 1998 to October 2013. Inclusion criteria were met by 12 studies that compared MRA with digital subtraction angiography as reference standard. Two independent reviewers evaluated the methodological quality of the studies. Data from eligible studies were extracted and used to construct 2×2 contingency tables on a per-aneurysm level. Pooled estimates of sensitivity and specificity were calculated for all studies and subgroups of studies. Heterogeneity was tested, and risk for publication bias was assessed. Included studies were of high methodological quality. Studies with larger sample size tended to have higher diagnostic performance. Most studies used time-of-flight MRA technique. Among the 960 patients assessed, 772 aneurysms were present. Heterogeneity with reference to sensitivity and specificity was moderate to high. Pooled sensitivity of MRA was 95% (95% confidence interval, 89%-98%), and pooled specificity was 89% (95% confidence interval, 80%-95%). False-negative and false-positive aneurysms detected on MRA were mainly located at the skull base and middle cerebral artery. Freehand 3-dimensional reconstructions performed by the radiologist significantly increased diagnostic performance. Studies performed on 3 Tesla showed a trend toward higher performance (P=0.054). Studies on diagnostic performance of MRA show high sensitivity with large variation in specificity in the detection of intracranial aneurysms.

Detection, characterization and endovascular therapy planning of intracranial aneurysms with 16-channel multidetector row CT angiography

AimTo study the role of multidetector row CT angiography (MDCTA) in detection, characterization and endovascular therapy planning of intracranial aneurysms in comparison with digital subtraction angiography (DSA). Material and methodsBetween April 2011 and March 2012, prospective study of 43 patients with suspected cerebral aneurysms (27 females and 16 males) was done, their ages ranged from 40 to 74years. Patients were referred to the Radiodiagnosis Department, from neurology and neuro-surgery departments for suspected cerebrovascular lesions. Aneurysm detection with multidetector CT angiography and DSA was analyzed. ResultsThe MDCT angiograms were interpreted for the presence, location, size, ratios of the aneurysm (dome to neck ratio (D/N), aspect ratio), neck width, lobularity of the aneurysms and relationship of the aneurysm with the adjacent arterial branches, by using volume-rendering techniques.MDCT and DSA were done for all patients. Twenty-three patients had a single aneurysm, 4 had 2 aneurysms, 2 had 5 aneurysms and no aneurysms were detected in 14 patients presented with subarachnoid hemorrhage on unenhanced CT, the most common shape was saccular aneurysm (90%) and the most common size was medium size (43.9%). We determined the neck of 28 aneurysm (68%) and the remaining 13 could not be determined (32%).Among 41 cerebral aneurysms, 26 aneurysms were detected in anterior circulation (63.4%) and 15 in posterior circulation (36.5%). The middle cerebral artery (29.2%) was the most common site.In 55% of studied cases presented with aneurysmal rupture SAH was the commonest type of hemorrhage. According to Hunt and Hiss classification grades 2 and 3 were the most prevalent (17 patients and 6 patients respectively) followed by grade 4 (4 patients) and lastly grades 0 and 1 (one patient for each). ConclusionSixteen channel Multidetector CT angiography offers high diagnostic accuracy nearly equivalent to that of DSA in the detection of intracranial aneurysms. However, 16 channel- MDCTA still has limited sensitivity in detecting aneurysms of 3mm or less, despite its technical advances. MDCT can be used as a reliable alternative imaging technique to DSA in selected cases.

Comparison of 3D TOF-MRA and 3D CE-MRA at 3 T for imaging of intracranial aneurysms

PurposeTo compare 3T elliptical-centric CE MRA with 3T TOF MRA for the detection and characterization of unruptured intracranial aneurysms (UIAs), by using digital subtracted angiography (DSA) as reference. Materials and methodsTwenty-nine patients (12 male, 17 female; mean age: 62 years) with 41 aneurysms (34 saccular, 7 fusiform; mean diameter: 8.85mm [range 2.0–26.4mm]) were evaluated with MRA at 3T each underwent 3D TOF-MRA examination without contrast and then a 3D contrast-enhanced (CE-MRA) examination with 0.1mmol/kg bodyweight gadobenate dimeglumine and k-space elliptic mapping (Contrast ENhanced Timing Robust Angiography [CENTRA]). Both TOF and CE-MRA images were used to evaluate morphologic features that impact the risk of rupture and the selection of a treatment. Almost half (20/41) of UIAs were located in the internal carotid artery, 7 in the anterior communicating artery, 9 in the middle cerebral artery and 4 in the vertebro-basilar arterial system.All patients also underwent DSA before or after the MR examination. ResultsThe CE-MRA results were in all cases consistent with the DSA dataset. No differences were noted between 3D TOF-MRA and CE-MRA concerning the detection and location of the 41 aneurysms or visualization of the parental artery. Differences were apparent concerning the visualization of morphologic features, especially for large aneurysms (>13mm). An irregular sac shape was demonstrated for 21 aneurysms on CE-MRA but only 13/21 aneurysms on 3D TOF-MRA. Likewise, CE-MRA permitted visualization of an aneurismal neck and calculation of the sac/neck ratio for all 34 aneurysms with a neck demonstrated at DSA. Conversely, a neck was visible for only 24/34 aneurysms at 3D TOF-MRA. 3D CE-MRA detected 15 aneurysms with branches originating from the sac and/or neck, whereas branches were recognized in only 12/15 aneurysms at 3D TOF-MRA. ConclusionFor evaluation of intracranial aneurysms at 3T, 3D CE-MRA is superior to 3D TOF-MRA for assessment of sac shape, detection of aneurysmal neck, and visualization of branches originating from the sac or neck itself, if the size of the aneurysm is greater than 13mm. 3T 3D CE-MRA is as accurate and effective as DSA for the evaluation of UIAs.

Can CT angiography rule out aneurysmal subarachnoid haemorrhage in CT scan-negative subarachnoid haemorrhage patients?

Current management guidelines for CT scan-negative subarachnoid haemorrhage (SAH) patients recommend cerebral digital subtraction angiography (DSA). We aimed to investigate the utility of CT angiography (CTA) as a substitute for DSA in these patients. We included patients who presented with SAH confirmed by spectrophotometric xanthochromia analysis of cerebrospinal fluid (CSF) whereby the CT scan was negative. Electronic records were reviewed to collect data on non-contrast CT scan, CTA and DSA results. Patients without DSA or with other explanations for CSF xanthochromia were excluded. Sixty-three patients with CT scan-negative SAH were included. The diagnosis of SAH was confirmed by CSF analysis. All 63 patients underwent both DSA and CTA. Using DSA as the benchmark, CTA demonstrated a negative predictive value, positive predictive value, sensitivity and specificity of 98%, 82%, 90% and 96%, respectively, for the detection of intracranial aneurysms. CTA correctly identified patients in whom there were no underlying aneurysms responsible for SAH, with one patient with suspected dissection referred for further evaluation using MRI and DSA.

Role of MRA in the detection of intracranial aneurysm in the acute phase of subarachnoid hemorrhage

Magnetic resonance angiography (MRA) has been evaluated for the detection of unruptured intracranial aneurysms with favorable results at 3 Tesla (3T) and with similar diagnostic accuracy as both 3D time-of-flight (3D-TOF) and contrast-enhanced (CE-MRA) MRA. However, the diagnostic value and place of MRA in the detection of ruptured aneurysms has been little evaluated. Thus, the goal of this prospective single-center series was to assess the feasibility and diagnostic value of 3T 3D-TOF MRA and CE-MRA for aneurysm detection in acute non-traumatic subarachnoid hemorrhage (SAH). From March 2006 to December 2007, all consecutive patients admitted to our hospital with acute non-traumatic SAH (≤10 days) were prospectively included in this study evaluating MRA in the diagnostic workup of SAH. Feasibility of MRA and sensitivity/specificity of 3D-TOF and CE-MRA were assessed compared with gold standard DSA. In all, 84 consecutive patients (45 women, 39 men; age 23-86 years) were included. The feasibility of MRA was low (43/84, 51.2%). The reasons given for patients not undergoing magnetic resonance imaging (MRI) examination were clinical status (27 patients), potential delay in aneurysm treatment (11 patients) and contraindications to MRI (three patients). In patients explored by MRA, the sensitivity of CE-MRA (95%) was higher compared with 3D-TOF (86%) with similar specificity (80%). Also, 3D-TOF missed five aneurysms while CE-MRA missed two. The value of MRA in the diagnostic workup of ruptured aneurysms is limited due to its low feasibility during the acute phase of bleeding. Sensitivity for aneurysm detection was good for both MRA techniques, but tended to be better with CE-MRA.

High WSS or Low WSS? Complex Interactions of Hemodynamics with Intracranial Aneurysm Initiation, Growth, and Rupture: Toward a Unifying Hypothesis

Increasing detection of unruptured intracranial aneurysms, catastrophic outcomes from subarachnoid hemorrhage, and risks and cost of treatment necessitate defining objective predictive parameters of aneurysm rupture risk. Image-based computational fluid dynamics models have suggested associations between hemodynamics and intracranial aneurysm rupture, albeit with conflicting findings regarding wall shear stress. We propose that the "high-versus-low wall shear stress" controversy is a manifestation of the complexity of aneurysm pathophysiology, and both high and low wall shear stress can drive intracranial aneurysm growth and rupture. Low wall shear stress and high oscillatory shear index trigger an inflammatory-cell-mediated pathway, which could be associated with the growth and rupture of large, atherosclerotic aneurysm phenotypes, while high wall shear stress combined with a positive wall shear stress gradient trigger a mural-cell-mediated pathway, which could be associated with the growth and rupture of small or secondary bleb aneurysm phenotypes. This hypothesis correlates disparate intracranial aneurysm pathophysiology with the results of computational fluid dynamics in search of more reliable risk predictors.

Role of 3-D Conventional Angiography In Evaluation of Intra Carnial Aneurysms

Introduction: intracranial aneurysms are pathological enlargement of the brain arteries that are most commonly located in the circle of Willis. Intracranial aneurysms are relatively common with a prevalence of approximately 4%. The real danger of aneurysms is subarachnoid hemorrhage. 3D digital subtraction angiography has become a critical imaging tool in neuroradiology allowing for the visualization of detailed cerebral vasculature prior to any intervention. Aim of the work: The aim of this work is to evaluate the diagnostic performance of 3D conventional angiography in the evaluation of intracranial aneurysms compared with the conventional cerebral angiography. Methods: The studied group included 20 patients (5 men and 15 women) with subarachnoid hemorrhage or known to have cerebral aneurysms. All patients were subjected to conventional cerebral angiography and 3D cerebral angiography, using C-arm (Toshiba) rotational technique. Results: 3D digital subtraction angiography is superior to conventional digital subtraction angiography in 100% of the cases 3D imaging revealed the proper aneurysmal shape, size, precise assessment of its neck and relation to the surrounding vessels. Conclusion: Three-dimensional DSA improves the detection and delineation of intracranial aneurysms

Role of 3-D Conventional Angiography in Evaluation of Intra Carnial Aneurysms

Introduction: intracranial aneurysms are pathological enlargement of the brain arteries that are most commonly located in the circle of Willis. Intracranial aneurysms are relatively common with a prevalence of approximately 4%. The real danger of aneurysms is subarachnoid hemorrhage. 3D digital subtraction angiography has become a critical imaging tool in neuroradiology allowing for the visualization of detailed cerebral vasculature prior to any intervention. Aim of the work: The aim of this work is to evaluate the diagnostic performance of 3D conventional angiography in the evaluation of intracranial aneurysms compared with the conventional cerebral angiography. Methods: The studied group included 20 patients (5 men and 15 women) with subarachnoid hemorrhage or known to have cerebral aneurysms. All patients were subjected to conventional cerebral angiography and 3D cerebral angiography, using C-arm (Toshiba) rotational technique. Results: 3D digital subtraction angiography is superior to conventional digital subtraction angiography in 100% of the cases 3D imaging revealed the proper aneurysmal shape, size, precise assessment of its neck and relation to the surrounding vessels. Conclusion: Three-dimensional DSA improves the detection and delineation of intracranial aneurysms

Comparison of 64-slice CT angiography with 3D digital subtraction angiography in the diagnosis of intracranial aneurysms: a Meta-analysis

Background The difference of diagnostic accuracy of 64-slice computed tomography angiography (CTA) with 3D digital subtraction angiography (3D-DSA) in the detection of intracranial aneurysms is not clear yet. This study compares the diagnostic value of 64-slice CTA with 3D-DSA in the diagnosis of intracranial aneurysms via a Meta-analysis. Methods In this study, 64-slice, 64-row, CT, angiography, intracranial aneurysms, cerebral aneurysms, subarachnoid hemorrhage, etc. were used as key words, and searched in the electronic databases including Embase, MEDLINE, Cochrane Library, Chinese National Knowledge Infrastructure (CNKI), and Wanfang Data, assisted by manual searching, in order to retrieve articles both in English and Chinese that reported on comparisons of 64-slice CTA and 3D-DSA in the evaluation of suspected intracranial aneurysms. Meta-disc Version 1.4 was used for the Meta-analysis, and Quality Assessment of Diagnostic Accuracy Studies (QUADAS) was applied to assess the quality of these research studies. Results Four clinical trials were selected. According to the Meta-analysis, the pooled sensitivity, specificity, diagnostic odds ratios (DOR) and summary receiver operating characteristics (SROC) area under curve (AUC) was 97% (95% CI: 0.950-0.980), 91% (95% CI: 0.860-0.950), 269.640 (95% CI: 137.250-529.720) and 0.993 respectively. Conclusion On the basis of Meta-analysis, 64-slice CTA has a high level of sensitivity and specificity for diagnoses of intracranial aneurysms and it can be used as an important examination tool in the diagnoses of intracranial aneurysms. Because the sample size of selected studies is small, it is necessary to perform well-designed and larger sample studies to further assess the diagnostic value of intracranial aneurysms by 64-slice CTA.

Abstract TP87: Comparative Analysis of 3-Dimensional Rotation Angiography versus 3-Dimensional Computed Tomography Angiography for Intracranial Aneurysm Treatment Detection and Planning

Introduction: 3D Rotational Angiography (3DRA) is the gold standard for intracranial aneurysm (IA) detection, but is invasive and time consuming. While 3DCTA has shown to be sensitive for IA detection, no published studies have compared 3DRA to 3DCTA in guiding clinical management. Our aim was to compare suggested treatment for IA based on 3DRA and 3DCTA vs actual final treatment and outcome. Hypothesis: Management recommendations based on blinded review of 3DRA and 3DCTA for IA do not differ significantly. Methods: Prospective blinded review of contemporaneous 3DRA and 3DCTA was performed for patients with suspected IA. Two interventionalists and two neuroradiologists performed blinded, prospective review of 3DRA or 3DCTA, respectively. IA size, location, and morphology were assessed. After IA characterization, each observer independently recommended optimal therapy (conservative, coil, surgery, combined/other) while blinded to other reviewers’ decisions. Findings were analyzed with Spearman, and agreement coefficient 1 (AC1) inter-rater reliability statistics. Results: 41/52 enrolled patients had IA confirmed by 3DRA (52 IA total). 50/52 (96%) IA were initially identified by 3DCTA (both false negatives seen retrospectively). Average IA sac and neck size measured by 3DRA and 3DCTA correlated closely (p&lt;0.01) and were 9.8 and 5.0 mm vs 9.5 and 4.5 mm, respectively. Treatment recommendations by reviewers for 3DRA vs 3DCTA correlated very strongly (AC1= 0.77), as did reader recommendations within a modality (3DRA, AC1=0.66; 3DCTA, AC1=0.79). For 39/52 (75%) of IA, majority consensus for all readers was reached (3/4 or 4/4 reviewers), which correlated well with final executed treatments (95%). Conclusions: Recommendations for IA treatment based on 3DCTA correlate closely with those based on 3DRA, as well as with actual treatment in a majority of patients. 3DCTA holds promise as a primary imaging tool for IA detection and clinical decision making.

Intracranial Aneurysms in Patients With Carotid Disease

Before the routine use of computed tomography (CT) angiography, decisions for carotid artery treatment were mostly based on ultrasound findings and conventional angiography. Implementation and increasing use of CT angiography provided better visualization of the carotid and vertebrobasilar arteries system leading to an unexpected more frequent detection of unruptured intracranial aneurysms (UIAs). Concomitant presence of intracranial aneurysms in patients with severe carotid stenosis is a potential cause of significant mortality and morbidity. Due to the possible higher risk of aneurysm rupture after carotid procedures and ischemic events after aneurysm repair, the simultaneous presence of both lesions creates several therapeutic dilemmas. We review the prevalence of UIAs in patients with carotid occlusive disease and management difficulties and the current treatment strategies for handling the concomitant presence of these life-threatening diseases.

Evaluating of Small Intracranial Aneurysms by 64‐Detector CT Angiography: A Comparison with 3‐Dimensional Rotation DSA or Surgical Findings

The diagnostic performance of 64-detector computed tomographic angiography (CTA) for detection of small intracranial aneurysms (SIAs) was evaluated. In this prospective study, 112 consecutive patients underwent 64-detector CTA before volume-rendering rotation digital subtraction angiography (VR-RDSA) or surgery. VR-RDSA or intraoperative findings or both were used as the gold standards. The accuracy, sensitivity, specificity, and positive predictive values (PPV) and negative predictive values (NPV), as measures to detect or rule out SIAs, were determined by patient-based and aneurysm size-based evaluations. The reference standard methods revealed 84 small aneurysms in 71 patients. The results of patient-based 64-detector CTA evaluation for SIAs were: accuracy, 98.2%; sensitivity, 98.6%; specificity, 97.6%; PPV, 98.6%; and NPV, 97.6%. The aneurysm-based evaluation results were: accuracy, 96.8%; sensitivity, 97.6%; specificity, 95.1%; PPV, 97.6%; and NPV, 95.1%. Two false-positive and two false-negative findings for aneurysms <3 mm in size occurred in the 64-detector CTA analysis. The diagnostic performance of 64-detector CTA did not improve much compared with 16-detector CTA for detecting SIAs, especially for very small aneurysms. VR-RDSA is still necessary for patients with a history of subarachnoid hemorrhage if the CTA findings are negative.

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

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. 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. 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. 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.

Benefits of 3D Rotational DSA Compared with 2D DSA in the Evaluation of Intracranial Aneurysm

The aim of this study was to compare conventional two-dimensional (2D) digital subtraction angiography (DSA) with three-dimensional (3D) rotational DSA in the investigation of intracranial aneurysm in terms of detection, size measurement, neck diameter, neck delineation, and relationship with surrounding vessels. A further aim was to compare radiation dose, contrast volume, and procedural time between the two protocols. Thirty-five patients who presented with subarachnoid bleeds on computed tomography and were suspected of having intracranial aneurysms underwent conventional 2D DSA followed by 3D DSA. The 3D digital subtraction angiographic images were displayed as surface shaded display images. Aneurysm detection, sac size, neck diameter, neck delineation, and relationship of aneurysm to the surrounding vessels analyzed from the two protocols were compared. Radiation dose, contrast volume, and procedural time for both examinations were also compared. Three-dimensional DSA detected 44 aneurysms in 31 patients, with negative findings seen in four patients. A false-negative detection rate of 6.8% (three of 44) for 2D DSA was noted. There was no significant difference in aneurysm size between 3D and 2D DSA. The sizes of aneurysm necks were found to be significantly larger in 3D DSA than on 2D DSA. The aneurysm neck and relationship to surrounding vessels were significantly better demonstrated on 3D DSA than on 2D DSA. Radiation dose (entrance surface dose), contrast use, and procedural time with 3D DSA were significantly less than with 2D DSA. Three-dimensional DSA improves the detection and delineation of intracranial aneurysms, with lower radiation dose, less contrast use, and shorter procedural time compared to 2D DSA. The size of the aneurysm neck on 3D DSA tended to be larger than on 2D DSA.

Skull Base CT Slice Entropy Evaluation for a Novel Fully Automated Method of Intracranial Aneurysm Detection

Objective: Subarachnoid hemorrhage from intracranial aneurysms carries high rates of morbidity and mortality. Visual diagnosis (manual detection and segmentation) of aneurysms is a time-consuming and potentially unreliable task. Automated systems may improve accuracy and reliability. We report a novel technique for extraction of the intracranial arteries and a detection algorithm to detect potential aneurysms from CT angiograms. Using mathematical properties of the skull base slices, the cerebral arteries are extracted and the scope of the detection techniques reduced accordingly. Further image processing techniques are applied to the reduced scope image to detect and segment aneurysms.