AR: 3D DSA trumps 2D for aneurysm evaluation

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Digital Subtraction CTA of Aneurysm - 88.45 Kb
One true-positive aneurysm in 62-year-old woman. Volume-rendered digital subtraction CT angiographic image. Source: Radiology

Three-dimensional (3D) digital subtraction angiography (DSA) provides superior detection and delineation of intracranial aneurysms while exposing patients to less radiation, using less contrast and shortening overall procedure time, according to a study published in the June issue of Academic Radiology.

Previous studies have noted advantages of 3D DSA for the evaluation of cerebral aneurysms, including improved visualization of anatomic details compared with 2D DSA.

Siong Chuong Wong, MD, of the department of biomedical imaging at University Malaya Medical Centre in Kuala Lumpur, Malaysia, and colleagues sought to confirm the benefits of 3D DSA in the evaluation of intracranial aneurysms as well as consider the safety and workflow implications of the approach.

The study population included 35 patients referred for angiography for suspected intracranial aneurysm from August 2008 to November 2009. Patients underwent 2D DSA, followed by 3D rotational DSA. Images were reconstructed on a multimodality workstation and then reviewed, with 2D review preceding 3D analysis.  

The reviewers found 44 aneurysms on 3D DSA and 41 on a 2D DSA, yielding a false-negative rate of 6.8 percent for 2D DSA.

Wong and colleagues reported that 3D provided a statistically significant improvement in capability to delineate the aneurysm neck compared with 2D. 3D DSA enabled measurement of neck diameter on 43 aneurysms and 2D provided neck measurements of 31 aneurysms. In addition, diameters were significantly larger on 3D DSA versus 2D DSA at an average of 3.0 mm for 3D DSA and 2.6 mm for 2D DSA.

2D DSA resulted in a total mean radiation dose of 287.14 mGy and a mean additional views dose of 173.31 mGy compared with 93.25 mGy for 3D DSA, and the 2D approach also used significantly more contrast.

Finally, mean procedure time was longer for 2D DSA. The total mean 2D time was 189.2 seconds and 2D additional views mean time was 163.1 seconds compared with a 3D DSA mean time of 101.7 seconds. “This time saving is important, especially in critical patients, in whom angiographic procedure time needs to be as short as possible,” according to Wong et al.

“The recent adoption of 3D rotational angiography has enabled better understanding and discussion of complex intracranial vascular anatomy surrounding aneurysms among interventionists, neuroradiologists and neurosurgeons,” wrote Wong and colleagues. The researchers added to the list of benefits associated with 3D DSA, noting that providers can use the 3D datasets to better explain the treatment and its risks to patients.

The 3D approach also enables improved visualization of aneurysms in difficult locations, complex configurations and obscured aneurysm necks, which can result in better treatment planning, according to the researchers. They noted that improved visualization could inform the decision about coil placement or surgical clipping, and help providers select and deploy the optimal coil.   

Wong and colleagues also emphasized improved detection of smaller aneurysms with 3D DSA, which they attributed to its capability to rotate vessels that might obscure these aneurysms. The end result, they wrote, is enhanced diagnostic confidence.

“We recommend that in the investigation of intracranial aneurysm, 3D DSA should be performed following acquisition of standard 2D DSA projections. Additional 2D DSA views are only performed in working projections (derived from 3D DSA) that best depict the neck, for further analysis of neck size,” the researchers concluded.