O-014 Significant Acquisition Dose Reduction Maintains Diagnostic Quality of Biplane Cerebral Digital Subtraction Angiography
Authors: Honarmand A , Shaibani A , Hurley M , Patel B , Daruwalla V , Ansari S 
Published: July 2014

PurposeDigital subtraction angiography (DSA) remains the gold standard modality for evaluation, diagnosis, and treatment planning of several intracranial vascular abnormalities. However, patient radiation dose can be considerable with both diagnostic and especially complex neurointerventional procedures. Modern biplane flat-detector angiography units provide several possibilities for automatic dose reduction by modifying X-ray tube potential, current, pulse width, and filtration thickness. We aimed to investigate the feasibility of reducing the radiation exposure dose in diagnostic DSA examinations while preserving the overall image quality for diagnostic purposes.Materials and methodsFollowing IRB approval and informed consent, a prospective study was performed on patients undergoing diagnostic cerebral DSA using biplane flat detector rotational fluoroscopy and angiography unit (Artis zee/zeego, Siemens). DSA images were acquired using a predefined manufacturer standard DSA program by selecting detector dose of 3.6 μGy/ frame (mean typical tube voltage (TTV): 80.6 kVP, mean tube current (TC): 230.6 mA, using focal spot size (FS) of 0.6 and inherent filtration) and reduced DSA detector dose of 1.2 μGy/frame (mean TTV: 73.6 kVP, mean TC: 153.5 mA, using FS of 0.3 with additional 0.1/0.2 copper filter) dose protocols for each patient. Using identical contrast agent, contrast injection rate, and fluoroscopy time, randomly selected internal carotid arteries or vertebral arteries and their contralateral equivalent arteries were injected to obtain standard radiation dose and low radiation dose AP and lateral DSA images, respectively. Images were not included for image quality assessment if any significant technical issue and/or flow limiting vascular stenosis/occlusion, or steal phenomenon from AV shunts were present. Image quality assessment was performed independently by two neurointerventionalists on a de-identified PACS workstation. A 5 point scale (5: Very good: excellent large and small vessel visualization; 4: Good: excellent large vessel and minimal compromise of small vessel visualization; 3: Average: diagnostic value for large vessel, but compromised small vessel visualization 2: Poor: compromised large and small vessel visualization; 1: Nondiagnostic) was used for qualitative evaluation of arterial, capillary, and venous phases of DSA images respectively. The total score was defined as the overall diagnostic value. Paired sample t-test and Wilcoxon’s signed rank test compared the kerma-area product (KAP) and scores assigned to image quality parameters, respectively. P value <0.05 was considered statistically significant.ResultsTwenty-three DSA image series were obtained from nine patients (8M/1F, mean age: 65.9 ± 9.16) undergoing diagnostic DSA. Mean KAP was significantly reduced by 60% or 2.5 fold (1408.90 ± 419.18 μGy/m2vs. 557.08 ± 214.56 μGy/m2, P < 0.0001). No significant difference was observed between image quality scores assigned by the observers while assessing arterial (observer 1: P = 1.0; observer 2: P = 0.24), capillary (observer 1: P = 0.54; observer 2: P = 0.3), venous (observer 1: P = 0.14; observer 2: P = 0.7) phases, and overall diagnostic value (observer 1: P = 0.34; observer 2: P = 0.8).ConclusionsRadiation exposure dose can be reduced significantly without compromising image quality for diagnostic purposes in cerebral DSA studies.DisclosuresA. Honarmand: None. A. Shaibani: None. M. Hurley: None. B. Patel: None. V. Daruwalla: None. S. Ansari: None.