EP- 41 - Discordance of CTA and Digital Subtraction Angiography in Diagnosing

Vasospasm Following Subarachnoid Hemorrhage

ASNR 53rd Annual Meeting – April 25-30, 2015

Thomas R. Williams, MD

Jason W. Allen, MD, PhD

Ryan P. Beck, MD

Frank C. Tong, MD

Seena Dehkharghani, MD

Department of Radiology and Imaging Sciences

Division of Neuroradiology

Disclosures

The authors have no relevant disclosures.

Background

Vasospasm is a leading cause of morbidity and

mortality in patients surviving aneurysmal

subarachnoid hemorrhage (aSAH).

Prevalence of vasospasm approaches 70% in the

first two weeks following aSAH.

Background

Digital subtraction angiography (DSA) is the gold

standard for the diagnosis of vasospasm.

DSA is invasive, time-intensive, and not widely

available.

CT Angiography (CTA) is an attractive alternative

to DSA given non-invasive nature, speed of the

exam, and ubiquitous availability.

Purpose

The purpose of this study is to analyze the degree

of concordance between CTA and DSA in the

diagnosis of vasospasm in patients with aSAH.

Materials and Methods

Two board-certified neuroradiologists reviewed the

head CTAs of 15 patients with aSAH and a clinical

concern for vasospasm.

Arteries were scored for vasospasm on a four

point scale.

0 = none 1 = mild

2 = moderate 3 = severe

Materials and Methods

Each vasospasm score was also assigned a

degree of confidence in the diagnosis.

Low or high confidence

The following arteries were scored in each case:

Bilateral supraclinoid ICAs, bilateral A1 ACA segments,

bilateral distal ACAs, bilateral M1 MCA segments, bilateral

distal MCAs, bilateral PCAs, and basilar artery.

Materials and Methods

Neurointerventionalist subsequently and

independently analyzed the DSAs on this same set

of patients.

DSAs were obtained within 8 hours of the respective CTA.

The same scoring system and confidence ratings were used.

Statistical analysis of the concordance between

the interpretations of the CTAs and DSAs was then

calculated.

Results

Agreement in the score of vasospasm on CTA and

DSA was seen in 45% (88 of 195) of the vessels

scored.

Scores on CTA and DSA were discordant by one

point in 27% (53 of 195) of the vessels scored, and

by two or more points in 28% (54 of 195) of the

vessels scored.

Results

99% of scores on DSA given a score of high

confidence.

By contrast, 75% of scores on CTA given a score

of high confidence.

No trend towards overestimation or

underestimation of vasospasm on CTA identified.

Results

DSA and CTA images of one patient following aSAH. Vasospasm in the basilar artery was scored as mild on the DSA, while it was scored

having focal severe vasospasm on the CTA. Both scores were given a high degree of confidence.

Results

DSA and CTA images of another patient. Vasospasm in the basilar artery was scored as moderate on the DSA and severe on the CTA. Both scores were given

a high degree of confidence.

Results

DSA and CTA images of a third patient showing concordance between DSA and CTA with both showing focal severe vasospasm of the left A1 segment. Both scores were again given a high degree of confidence.

Conclusions

CTA has high reported rate of concordance with

DSA, 93%, in the detection of cerebral aneurysms.

In this study, the concordance between CTA and

DSA in the evaluation of vasospasm is much

lower.

Conclusions

The lower concordance between CTA and DSA in

vasospasm is believed to be secondary to multiple

patient and modality-specific factors, which are

more easily controlled with DSA, including:

Poor contrast bolus

Patient motion/compliance

Venous contamination

Artifact from coil/clip material

Artifact from adjacent blood products

References Chappell ET, Moure FC, Good MC. Comparison of computed

tomographic angiography with digital subtraction angiography in

the diagnosis of cerebral aneurysms: a meta-analysis.

Neurosurgery 2003:52:631-641.

Diringer MN. Management of aneurysmal subarachnoid

hemorrhage. Crit Care Med 2009:37:432-440.

Wintermark, M, Ko NU, Smith WS, et al. Vasospasm after

subarachnoid hemorrhage: utility of perfusion CT and CT

angiography on diagnosis and management. Am J Neuroradiol

2006:27:26-34.