Role of time-resolved-CTA in intracranial arteriovenous malformation evaluation at 128-slice CT in comparison with digital subtraction angiography

Analysis of the role of perfusion parameters in predicting rupture of brain arteriovenous malformations: a multi-center study

This study aimed to investigate the potential correlation between the perfusion parameters of brain arteriovenous malformations (bAVMs) as determined by multiphase CT angiography and bAVM rupture. Based on the occurrence of bAVM-related hemorrhage, 480 diagnosed bAVM patients were divided into hemorrhage (n = 220) and non-hemorrhage (n = 260) groups in this retrospective multi-center study spanning 2010 to 2020. On initial rupture CT images, the bAVM nidus and major draining vein were segmented, and time-density curves were extracted to compute perfusion parameters including mean transit time (MTT), time to peak (TTP), blood volume (BV), and blood flow (BF). To examine the potential correlation between these parameters and bAVM rupture, logistic regression was utilized to analyze multifactorial data and compare differences between the two groups. The ruptured group demonstrated a bAVM nidus characterized by an increased BF, a shorter TTP and MTT, and a higher peak density. The veins that were draining exhibited a reduced TTP, MTT, and peak density. A nidus TTP of less than 4s was identified by the multifactorial analysis as a critical risk factor for bAVM rupture. The statistical results highlight the noteworthy correlation between nidus TTP and bAVM rupture, presenting an original framework for assessing the risk of rupture.

Angiographic analysis on posterior fossa hemorrhages and vascular malformations beyond aneurysms by CT angiography and digital subtraction angiography

Background

Posterior fossa malformations are less common than supratentorial malformations, but hemorrhages in posterior fossa are more serious due to presence of vital structures within this region. Most common cause of bleed in posterior fossa apart from hypertension is aneurysms but other vascular malformations are also there which cause hemorrhage. Here we discuss other causes of posterior fossa bleed beyond aneurysms.

Results

A total of 80 patients were evaluated: 47 (58.8%) had aneurysms, 29 (36.3%) had arteriovenous malformations, one each had developmental venous anomaly and brainstem cavernoma. Thirty vascular malformations were detected, of which 18 (62.1%) were pial arteriovenous malformations (AVMs), 11 (37.9%) were dural arteriovenous fistulas (dAVF), and one had developmental venous anomaly (DVA). Six patients of AVM underwent both DSA and CTA, and CTA could correctly diagnose only 2 of 4 pial AVMs detected by DSA. Among two dAVFs detected by DSA, CTA could demonstrate dAVF only in one patient.

Conclusion

CTA could be used as alternative to DSA in diagnosis and characterizing aneurysms in posterior fossa but for AVMs, 3D-CTA cannot replace DSA; however potential of time-resolved CTA (TR-CTA) appears promising.

Low-dose contrast-enhanced time-resolved angiography with stochastic trajectories with iterative reconstruction (IT-TWIST-MRA) in brain arteriovenous shunt

OBJECTIVES

To assess the feasibility of low-dose contrast-enhanced four-dimensional (4D) time-resolved angiography with stochastic trajectories (TWIST) with iterative reconstruction (hereafter IT-TWIST-MRA) covering the whole brain and to compare IT-TWIST-MRA and TWIST-MRA with reference to digital subtraction angiography (DSA) in the evaluation of arteriovenous shunts (AVS).

METHODS

Institutional Review Board approval was obtained for this observational study, and the requirement for written informed consent was waived. Twenty-nine patients with known AVS underwent TWIST-MRA on a 3-T MRI scanner, using low-dose injection (0.02 mmol/kg) of gadolinium-based contrast agent (GBCA) with each of Fourier and iterative reconstruction between September 2016 and October 2019. Visual evaluation of image quality was conducted for delineation of (a) the normal cerebral arteries and veins and (b) AVS feeder, shunt, and drainer vessels. Region-of-interest evaluation was conducted to evaluate bolus sharpness and baseline signal fluctuation in the signal intensity of the cerebral vessels. We compared the detection of AVS between TWIST-MRA and IT-TWIST-MRA. The paired-samples Wilcoxon test was used to test the differences between TWIST-MRA and IT-TWIST-MRA.

RESULTS

Visualization scores for normal vasculature and AVS angioarchitecture were significantly better for images produced using IT-TWIST-MRA than those using TWIST-MRA. Peak signal and the enhancement slope of the time-intensity curve were significantly higher for IT-TWIST-MRA than for TWIST-MRA, except for the superior sagittal sinus (SSS). Baseline intensity fluctuation was significantly lower for IT-TWIST-MRA than for TWIST, except for SSS.

CONCLUSIONS

IT-TWIST-MRA yields clinically feasible 4D MR-DSA images and delineates AVS even with low-dose GBCA.

KEY POINTS

• Iterative reconstruction significantly improves the image quality of TWIST-MRA covering the whole brain. • The short temporal footprint and denoising effect of iterative reconstruction enhances the quality of 4D-MRA. • IT-TWIST-MRA yields clinically feasible images of AVS with low-dose GBCA.

Is four-dimensional CT angiography as effective as digital subtraction angiography in the detection of the underlying causes of intracerebral haemorrhage: a systematic review

PURPOSE

To determine whether the sensitivity and specificity of four-dimensional CTA (4D-CTA) are equivalent to digital subtraction angiography (DSA) in the detection of underlying vascular abnormalities in patients with intracerebral haemorrhage (ICH).

METHODS

A systematic review of studies comparing 4D-CTA with DSA in the detection of the underlying structural causes of ICH was performed on the literature published between 1998 and 2019.

RESULTS

We identified a total of 237 articles from PubMed, SCOPUS and Web of Science using the following Medical Subject Headings (MeSH) terms: primary intracerebral haemorrhage, 4D-CTA, DSA, cerebral haemorrhage, angiography, digital subtraction, arteriovenous malformations, 4D, CTA, dynamic-CTA and time-resolved CTA. Following the removal of duplicate publications and articles failing to meet our inclusion criteria, there were four articles potentially viable for analysis. Therefore, there were not sufficient studies to provide a statistically meaningful meta-analysis.

CONCLUSION

The review of current literature has demonstrated that there are few published studies comparing 4D-CTA with DSA in spontaneous ICH, with only four suitable studies identified for potential analysis. However, due to the restricted number of patients and high sensitivity and specificity of 3 studies (100%), performing a meta-analysis was not meaningful. Qualitative analysis of the data concluded that 4D-CTA has the diagnostic potential to replace invasive DSA in certain cases with vascular abnormalities. However, further research studies directly comparing 4D-CTA with DSA using larger prospective patient cohorts are required to strengthen the evidence base.

A cerebral arteriovenous malformation mistakenly diagnosed as dry eye and glaucoma: a case report

Background

To report the first case of a cerebral arteriovenous malformation (AVM) with ocular symptoms and review the characteristics of this case and the main point of confusion for the diagnosis of such a case.

Case presentation

A 58-year-old woman presented to the ophthalmology clinic with 1 and a half years of right eye redness, ocular hypertension and recurrent headache. One and a half years ago she was diagnosed with right eye dry eye and glaucoma and had received treatment according to this diagnosis. However, none of the treatments led to any improvement in redness and headache. Physical examination revealed dry eye and severe corkscrew hyperaemia with dilated vessels in the right eye. The results of fundoscopic examination of both eyes were normal. After we considered that the symptoms may be related to abnormal intracranial vessels, computed tomography angiography and venography (CTA + CTV) were performed, and the results showed an arteriovenous malformation in the right parietal-occipital area in the brain. The AVM was definitively located by further examination with digital subtraction angiography (DSA). After AVM endovascular embolism treatment, the conjunctival congestion of the right eye was significantly relieved, and the intraocular pressure decreased to normal.

Conclusion

In clinical practice, when corkscrew hyperaemia accompanied by neurological symptoms is found, cerebral vascular diseases might be considered. In this case, the ophthalmologist’s diagnosis should combine disease history and imaging examination.