Cerebral aneurysm exclusion by CT angiography based on subarachnoid hemorrhage pattern: a retrospective study

Giant Cerebral Aneurysms: Comparing CTA, MRA, and Digital Subtraction Angiography Assessments

BACKGROUND AND PURPOSE

Comprehensive imaging characterization of the morphology and luminal patency of cerebral aneurysms are cornerstones of their successful treatment and subsequent appropriate management. Giant cerebral aneurysms (GCAs), a distinct subgroup of aneurysms, are defined by large size (≥ 25 mm in greatest diameter), complex blood flow dynamics, and a high risk of rupture. The purpose of this study is to explore compare multiple imaging modalities in the assessment of GCAs.

METHODS

This study retrospectively evaluated CT angiography (CTA), 3D time-of-flight (TOF) MR angiography (MRA), contrast-enhanced MRA (CEMRA), and digital subtraction angiography (DSA) in characterizing GCAs in 21 patients.

RESULTS

Aneurysm size ranged from 26 to 58 mm (mean 31.3 ± 12.2) and 18/21 (85.7%) had intraluminal thrombus. No significant difference was found between the aneurysmal sizes of any two modalities regarding comparisons of CTA, 3D TOFMRA, and CEMRA. However, there were significant differences in the aneurysmal patency visibility grade between CTA versus TOFMRA and CTA versus CEMRA. Moreover, the patent luminal size measured on CTA was significantly larger than DSA.

CONCLUSIONS

CTA, 3D TOFMRA, and CEMRA are equivalent in the delineation of size of GCAs. Nevertheless, 3D TOFMRA and CEMRA seem to be inferior to CTA in demonstrating luminal size/patency, likely because of the signal loss resulting from the presence of intraluminal thrombus and flow turbulence. Moreover, CTA is superior to DSA in determining lumen patency in GCAs, probably due to CTA's multipass-related luminal enhancement while DSA general fills the lesion via the first pass of enhancement or soon thereafter. In addition, CTA may also better demonstrate intraluminal thrombus, adjacent anatomical structures, and calcified rims.

Intracranial vessel wall imaging: applications, interpretation, and pitfalls

Vessel wall imaging (VWI) is being increasingly used as a non-invasive diagnostic method to evaluate the intra- and extracranial vascular bed. Whereas conventional vascular imaging primarily assesses the vessel lumen, VWI changes the focus of analysis toward the vessel wall. As the technical challenges of high spatial resolution, signal-to-noise ratio, and contrast-to-noise ratio and long scans times are addressed, interest in the clinical applications of this technique has steadily increased over the years. In this review, the authors will discuss the various applications of VWI as well as principles of interpretation and common imaging findings, focusing on intracranial atherosclerosis, vascular dissection, vasculitides (such as primary angiitis of the central nervous system (PACNS) and neurosarcoidosis), vasculopathies (such as reversible cerebral vasoconstriction syndrome (RCVS), cocaine-induced vasculopathy, moyamoya disease, and radiation-induced arteriopathy), aneurysms, and post-thrombectomy changes. The authors will also discuss the potential pitfalls of VWI and helpful cues to avoid being tricked.

Digital subtraction cerebral angiography after negative computed tomography angiography findings in non-traumatic subarachnoid hemorrhage

Background

CT angiography (CTA) is widely used for the detection of vascular lesions in patients with non-traumatic subarachnoid hemorrhage (ntSAH); however, digital subtraction angiography (DSA) remains the gold standard for diagnosis. Our aim was to analyze the diagnostic yield of DSA after negative high-resolution CTA findings.

Methods

Records of patients with a CTA-negative ntSAH at a single institution from 2014 to 2018 were retrospectively analyzed. ntSAH patterns were categorized as cortical, perimesencephalic, or diffuse. Subsequent DSA findings were compared across the three cohorts.

Results

A total of 186 patients had CTA-negative ntSAH. The ntSAH pattern was identified as cortical (n=77, 41.4%), diffuse (n=60, 32.3%), or perimesencephalic (n=49, 26.3%). In eight patients (4%), DSA revealed a vascular lesion (one cervical arteriovenous fistula and seven atypical aneurysms) after negative CTA findings. All eight patients with positive DSA findings had diffuse SAH (13% of patients with a diffuse pattern). The seven aneurysms included four blister or dissecting (two basilar artery, one superior cerebellar artery, and one dorsal wall internal carotid artery), two fusiform (one posterior communicating artery and one anterior spinal artery), and one saccular aneurysm (middle cerebral artery).

Conclusion

DSA identified a causative lesion in 4% of patients with CTA-negative ntSAH, but only in patients with diffuse ntSAH. Most of the lesions detected were atypical aneurysms and were found on delayed angiograms. These results suggest that DSA can help to diagnose CTA-negative ntSAH caused by unusual aneurysms, and repeat DSA may be needed only for patients with diffuse ntSAH.

CT angiogram negative perimesencephalic subarachnoid hemorrhage: is a subsequent DSA necessary? A systematic review

Background

Perimesencephalic subarachnoid hemorrhage (PMSAH) is a benign subtype with distinct clinical-radiologic features. Digital subtraction angiography (DSA) remains the gold standard investigation for exclusion of a macrovascular cause, although increasingly more clinicians rely solely on CT angiography (CTA). The primary aim of this systematic review was to evaluate the current literature regarding the negative predictive value of CTA.

Methods

A systematic search in concordance with the PRISMA checklist was performed for studies published between 2000 and 2018. Studies with ≥10 adult patients diagnosed on a non-contrast brain CT with a PMSAH, who underwent a negative CTA and were subsequently subject to a DSA, were included. Simple pooled analysis was performed to inform the negative predictive value (95% CI) of CTA and the risk of DSA- and CTA-related complications.

Results

Eighteen studies (669 patients) were included. All patients were subject to at least one DSA, the first one mostly performed within 24 hours of CTA (68.6%). 144 patients (21.5%) underwent a second DSA and a third repeat DSA was performed in one patient. The overall negative predictive value of CTA was 99.0% (95% CI 97.8% to 99.5%). The risk of complications following DSA and CTA were 1.35% (3/222) and 0% (0/41), respectively.

Conclusions

Undertaking a DSA after a negative CTA may not add any further diagnostic value in patients with PMSAH and may lead to net harm. This observation needs to be validated in a large-scale prospective multicenter study with complete case ascertainment and robust data on CTA and DSA complications.

Digital Subtraction Angiography for CT Angiogram Negative Haemorrhages

BACKGROUND

In patients with subarachnoid haemorrhage (SAH) and a negative finding on CT angiography (CTA), further imaging with digital subtraction angiography (DSA) is commonly performed to identify the source of bleeding. The purpose of this study was to investigate whether negative findings on CTA can reliably exclude aneurysms in patients with acute SAH.

METHODS

This retrospective study identified all DSAs performed between August 2010 and July 2014 within our institution. CT angiography was performed with a 64-section multidetector row CT scanner. Only DSAs from patients with confirmed SAH and a negative CTA result were included in the final analyses. A fellowship-trained neuroradiologist reviewed the imaging results.

RESULTS

Of the 857 DSAs, 50 (5.83%) were performed in 35 patients with CTA-negative SAH. Of the 35 patients, three (8.57%) had positive findings on the DSA. In one patient, suspicious dissection of the extra- and intra-cranial segment of the right vertebral artery could not be confirmed even in retrospect. In the second patient, the suspicious finding of tiny protuberance from the left paraclinoid internal carotid artery (ICA) on DSA did not change on follow-up and did not change patient's management. The third patient had a posterior inferior cerebellar artery aneurysm, which was not seen on the initial CTA owing to the incomplete coverage of the head on the CTA.

CONCLUSION

In patients with SAH, negative findings on a technically sound CTA are reliable in ruling out aneurysms in any pattern of SAH or no blood on CT. Our observations need to be confirmed with larger prospective studies.

Management of Spontaneous Subarachnoid Hemorrhage Patients with Negative Initial Digital Subtraction Angiogram Findings: Conservative or Aggressive?

Background. The ideal management of SAH patients with negative initial DSA findings remains unresolved. Objective. (i) To present risk factors, clinical courses, and outcomes in different types of SAH patients with negative DSA findings; (ii) to explore the differences of basal vein between aSAH patients and NASAH patients; and (iii) to evaluate the value of repeated DSA for these patients. Methods. All SAH patients with negative initial DSA findings between 2013 and 2015 in our hospital were enrolled and were further categorized as perimesencephalic SAH (PMN-SAH) or nonperimesencephalic SAH (nPMN-SAH). Risk factors, clinical courses, outcomes, and the basal vein drainage patterns were compared. Results. A total of 137 patients were enrolled in the present study. The PMN-SAH group had better GOS and mRS values at 1-year follow-up. Moreover, the nPMN-SAH group had a higher rate of complications. The basal vein drainage pattern showed significant difference when comparing each of the NASAH subtypes with aSAH groups. There was a significant higher rate of a responsible aneurysm in nPMN-SAH group upon repeated DSA. Conclusions. SAH patients with negative initial DSA findings had benign clinical courses and outcomes. Repeated DSA studies are strongly advised for patients with the nPMN-SAH pattern.

Radiographic diagnosis and endovascular treatment of an unruptured superior hypophyseal aneurysm

A 37-year-old female with a large unruptured superior hypophyseal aneurysm underwent a guglielmi detachable-coil embolization after proper diagnostic three-dimensional digital subtraction angiography (DSA) of the internal carotid artery. Only a few case reports exist in the scientific literature about this uncommon entity that accounts for 1% of all intracranial aneurysms. We discuss the etiology, prevalence, and incidence of saccular intracranial aneurysms as well as their risk factors, prognosis, and differential diagnosis. We also review the literature on intracranial aneurysm and evaluate its current diagnostic management and therapeutic treatment.

Cerebral Angiography for Evaluation of Patients with CT Angiogram-Negative Subarachnoid Hemorrhage: An 11-Year Experience

BACKGROUND AND PURPOSE

CT angiography is increasingly used to evaluate patients with nontraumatic subarachnoid hemorrhage given its high sensitivity for aneurysms. We investigated the yield of digital subtraction angiography among patients with SAH or intraventricular hemorrhage and a negative CTA.

MATERIALS AND METHODS

An 11-year, single-center retrospective review of all consecutive patients with CTA-negative SAH was performed. Noncontrast head CT, CTA, DSA, and MR imaging studies were reviewed by 2 experienced interventional neuroradiologists and 1 neuroradiologist.

RESULTS

Two hundred thirty patients (mean age, 54 years; 51% male) with CTA-negative SAH were identified. The pattern of SAH was diffuse (40%), perimesencephalic (31%), sulcal (31%), isolated IVH (6%), or identified by xanthochromia (7%). Initial DSA yield was 13%, including vasculitis/vasculopathy (7%), aneurysm (5%), arteriovenous malformation (0.5%), and dural arteriovenous fistula (0.5%). An additional 6 aneurysms/pseudoaneurysms (4%) were identified by follow-up DSA, and a single cavernous malformation (0.4%) was identified by MRI. No cause of hemorrhage was identified in any patient presenting with isolated intraventricular hemorrhage or xanthochromia. Diffuse SAH was due to aneurysm rupture (17%); perimesencephalic SAH was due to aneurysm rupture (3%) or vasculitis/vasculopathy (1.5%); and sulcal SAH was due to vasculitis/vasculopathy (32%), arteriovenous malformation (3%), or dural arteriovenous fistula (3%).

CONCLUSIONS

DSA identifies vascular pathology in 13% of patients with CTA-negative SAH. Aneurysms or pseudoaneurysms are identified in an additional 4% of patients by repeat DSA following an initially negative DSA. All patients with CT-negative SAH should be considered for DSA. The pattern of SAH may suggest the cause of hemorrhage, and aneurysms should specifically be sought with diffuse or perimesencephalic 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.

Influencing factors of immediate angiographic results in intracranial aneurysms patients after endovascular treatment

The purpose of this study was to analyze influencing factors associated with immediate angiographic results in intracranial aneurysms patients after endovascular treatment (EVT), providing theoretical evidence and guidance for clinical treatment of intracranial aneurysms. Totally 529 patients met the inclusive criteria, consisting of 338 males and 191 females. Gender; age; history of hypertension, diabetes, and smoking; intracranial atherosclerosis; rupture status, size and location, features of aneurysmal neck, shapes; vasospasm; treatment modality; and degree of aneurysm occlusion were all carefully and completely recorded. All data were investigated in univariate and multivariate logistic regression model to determine whether they were correlated with the degree of aneurysm occlusion. According to aneurysm size, aneurysms were classified as micro-miniature, miniature, and large aneurysms. There were 451 narrow-neck aneurysms and 78 wide-neck aneurysms. Totally 417 were regular and 112 were irregular. And 125 were un-ruptured aneurysms; 404 were ruptured aneurysms. The modalities of treatment were as follows: embolization with coil (n = 415), stent-assisted coil embolization (n = 89), and balloon-assisted coil embolization (n = 25). Univariate analysis showed that aneurysm size, feature of aneurysm neck, shape, and rupture status might affect the immediate occlusion after EVT. Multivariate logistic regression analysis indicated that ruptured aneurysm, tiny aneurysm, and wide-neck aneurysm were independent influencing factors of complete occlusion of intracranial aneurysm. Aneurysm rupture status, size, feature of aneurysmal neck, and shape might be the independent influencing factors of immediate angiographic results in intracranial aneurysm patients after EVT. Un-ruptured, micro-miniature, narrow-neck, and regular-shaped aneurysms were more probable to be occluded completely.

Use of Follow-Up Imaging in Isolated Perimesencephalic Subarachnoid Hemorrhage

Background and Purpose—

Multiple studies have shown that negative computed tomographic angiograms (CTAs) are reliable in excluding aneurysms in patients with isolated perimesencephalic subarachnoid hemorrhage (pSAH). We evaluate the use of digital subtraction angiography versus CTA for initial diagnosis and of angiographic follow-ups in patients with pSAH by performing an institutional analysis and a meta-analysis of literature.

Methods—

Retrospective institutional analysis of patients with pSAH was performed from 2008 to 2014. The number and types of follow-up imaging studies were tabulated. Initial and follow-up studies were evaluated by an experienced neuroradiologist for intracranial aneurysm. Meta-analysis of literature was performed to assess the use of initial digital subtraction angiography and of follow-up imaging.

Results—

Our institutional review revealed no additional use of initial digital subtraction angiography or of any angiographic follow-up after initial negative CTA in patients with pSAH on noncontrast CT. Meta-analysis of 40 studies yielded a total of 1031 patients. Only 8 aneurysms were first diagnosed on follow-ups (0.78%). Careful review showed that some of these aneurysms reported on follow-up are of questionable validity. Initial digital subtraction angiography and follow-up imaging after a negative initial CTA showed no statistically significant benefits.

Conclusions—

In patients meeting the strict imaging criteria of pSAH, initial negative CTA is reliable in excluding aneurysms. A critical review of the literature through meta-analysis shows no foundation for multiple follow-up studies in patients with pSAH.

Approach to the diagnosis and treatment of acute subarachnoid hemorrhage in a patient with sickle cell disease

We report a case of subarachnoid hemorrhage in a 38-year-old patient with sickle cell anemia. This case highlights the limitations of non contrast computed tomography in the diagnosis of subarachnoid hemorrhage in patients with sickle cell disease as well as the special needs of this patient population in addressing the treatment of stroke.

Nonaneurysmal perimesencephalic subarachnoid hemorrhage: diagnosis, pathophysiology, clinical characteristics, and long-term outcome

Patients with nonaneurysmal perimesencephalic subarachnoid hemorrhage (NAPSAH) have no discernible source for the bleeding and generally are considered to have a benign condition. Correctly diagnosing these patients is essential because a missed aneurysm can have catastrophic consequences. Those presenting with NAPSAH have a low risk of complications and better outcome than patients presenting with aneurysmal subarachnoid hemorrhage; however, a limited body of literature suggests that not all of these patients are able to return to their premorbid functional status. Clinical screens of cognitive status, such as the mini-mental status examination, suggest good recovery of these patients, although these tests may lack sensitivity for identifying deficits in this patient population. More comprehensive neuropsychologic testing in some studies has identified deficits in a wide range of cognitive domains at long-term follow-up in patients with NAPSAH. Because these patients often do not lose consciousness (and thus do not have substantial transient global ischemia) and they do not undergo a procedure for aneurysm repair, the cognitive sequelae can be explained by the presence of blood in the subarachnoid space. NAPSAH presents an opportunity to understand the effects of subarachnoid blood in a clinical setting.

Non-aneurysmal non-traumatic subarachnoid hemorrhage: patient characteristics, clinical outcome and prognostic factors based on a single-center experience in 125 patients

BACKGROUND

Subarachnoid hemorrhage (SAH) is mainly caused by ruptured cerebral aneurysms but in up to 15% of patients with SAH no bleeding source could be identified. Our objective was to analyze patient characteristics, clinical outcome and prognostic factors in patients suffering from non-aneurysmal SAH.

METHODS

From 1999 to 2009, data of 125 patients with non-aneurysmal SAH were prospectively entered into a database. All patients underwent repetitive cerebral angiography. Outcome was assessed according to the modified Rankin Scale (mRS) (mRS 0-2 favorable vs. 3-6 unfavorable). Also, patients were divided in two groups according to the distribution of blood in the CT scan (perimesencephalic and non-perimesencephalic SAH).

RESULTS

106 of the 125 patients were in good WFNS grade (I-III) at admission (85%). Overall, favorable outcome was achieved in 104 of 125 patients (83%). Favorable outcome was associated with younger age (P < 0.001), good admission status (P < 0.0001), and absence of hydrocephalus (P = 0.001).73 of the 125 patients suffered from perimesencephalic SAH, most patients (90%) were in good grade at admission, and 64 achieved favorable outcome.52 of the 125 patients suffered from non-perimesencephalic SAH and 40 were in good grade at admission. Also 40 patients achieved favorable outcome.

CONCLUSIONS

Patients suffering from non-aneurysmal SAH have better prognosis compared to aneurysm related SAH and poor admission status was the only independent predictor of unfavorable outcome in the multivariate analysis. Patients with a non-perimesencephalic SAH have an increased risk of a worse neurological outcome. These patients should be monitored attentively.

Subarachnoid hemorrhage: beyond aneurysms

OBJECTIVE

Spontaneous subarachnoid hemorrhage (SAH) typically prompts a search for an underlying ruptured saccular aneurysm, which is the most common nontraumatic cause. Depending on the clinical presentation and pattern of SAH, the differential diagnosis may include a diverse group of causes other than aneurysm rupture.

CONCLUSION

For the purposes of this review, we classify SAH into three main patterns, defined by the distribution of blood on unenhanced CT: diffuse, perimesencephalic, and convexal. The epicenter of the hemorrhage further refines the differential diagnosis and guides subsequent imaging. Additionally, we review multiple clinical conditions that can simulate the appearance of SAH on CT or MRI, an imaging artifact known as pseudo-SAH.

Improved arterial visualization in cerebral CT perfusion-derived arteriograms compared with standard CT angiography: a visual assessment study

BACKGROUND AND PURPOSE

Invasive cerebral DSA has largely been replaced by CTA, which is noninvasive but has a compromised arterial view due to superimposed bone and veins. The purpose of this study was to evaluate whether arterial visualization in CTPa is superior to standard CTA, which would eliminate the need for an additional CTA scan to assess arterial diseases and therefore reduce radiation dose.

MATERIALS AND METHODS

In this study, we included 24 patients with subarachnoid hemorrhage for whom CTA and CTP were available. Arterial quality and presence of superimposed veins and bone in CTPa were compared with CTA and scored by 2 radiologists by using a VAS (0%-100%). Average VAS scores were determined and VAS scores per patient were converted to a 10-point NRS. Arterial visualization was considered to be improved when the highest rate (NRS 10, VAS > 90%) was scored for arterial quality, and the lowest rate (NRS 1, VAS < 10%), for the presence of superimposed veins and bone. A sign test with continuity correction was used to test whether the number of cases with these rates was significant.

RESULTS

Average VAS scores in the proximal area were 94% (arterial quality), 4% (presence of bone), and 7% (presence of veins). In this area, the sign test showed that a significant number of cases scored NRS 10 for arterial quality (P < .02) and NRS 1 for the presence of superimposed veins and bone (P < .01).

CONCLUSIONS

Cerebral CTPa shows improved arterial visualization in the proximal area compared with CTA, with similar arterial quality but no superimposed bone and veins.

Assessment of an introductory cervicocerebral catheter angiography learning program: a pilot study

BACKGROUND AND PURPOSE

There is no standardized curriculum currently available at most institutions for establishing procedural competency in trainees performing cervicocerebral angiography. The purpose of this study was to evaluate a simple learning program to supplement the teaching of basic cervicocerebral angiography.

MATERIALS AND METHODS

An 11-session interactive curriculum was implemented covering anatomic, clinical, and radiographic topics for the novice cervicocerebral angiographer. The target learner was the neuroradiology fellow. Data were gathered regarding fellow comfort level on topics relating to cervicocerebral angiography by using a 5-point Likert scale. Improvement in scores on knowledge-based questions after completion of the curriculum was calculated (McNemar test). Trainee-perceived utility of the program was also recorded by using a 5-point Likert scale. Focus sessions were held at the completion of the curriculum to gather feedback regarding the strengths and weaknesses of the program from participants.

RESULTS

Ten subjects were enrolled in this pilot study for 3 years. Topics where participants reported a poor initial comfort level (4 or higher) included selection of injection rates and volumes and reformation of reverse-curve catheters. Trainees demonstrated a statistically significant change in the distribution of scores of 29.3% (49.4%-78.7% correct response rate, P < .0001). The average perceived utility was 1.5 (1 = most useful, 5 = least useful).

CONCLUSIONS

This simple learning program was a useful adjunct to the training of fellows in diagnostic cervicocerebral angiography, resulting in quantitative improvements in knowledge.