Detection Of Intracranial Aneurysms With Bone-subtraction CT Angiography (BSCTA): Comparison With Digital Subtraction Angiography

Objective:To investigate the value of Bone-subtraction CT Angiography in detecting intracranial aneurysms comparison with Digital Subtraction Angiography, and to analyze the relationship between an aneurysmal rupture and its morphology.Methods:Forty-nine patients (male 20 and female 29, aged from 28 to 76) who were clinically suspected with an intracranial aneurysm underwent both CTA and DSA. First, a feasibility analysis of the BSCTA image quality was done. With DSA as the gold standard, diagnostic test was done between NSCTA and BSCTA for diagnosis of intracranial aneurysms. Statistical analysis was performed to explore the associativity between aneurysmal rupture and its morphology.Results:1. The BSCTA image quality of forty-nine patients in the skull base, including 20 Vascular segments, were high (more than 90% of cases were rated good or excellent). And the score results of BSCTA subtraction effect showed that 91.8%(45/49) of cases were rated good or excellent.2. Sensitivity, specificity, accuracy of NSCTA were 95.7%,100%,96.2% for aneurysm detection, respectively. Whereas sensitivity, specificity, accuracy of BSCTA all reached 100%.3. BSCTA had a significant relation with DSA on aneurysmal morphology(p<0.05),and the aneurysmal aspect ratio was the strongest correlation (r=0.962);4. The relationship between aneurysmal neck and rupture in the 46 patients was analyzed through chi-square test. Statistical difference has been found in the incidence of rupture between wide-necked aneurysms and narrow-neck aneurysms.5. By calculated the aneurysmal aspect ratio(D/N value) in different locations, statistical difference between ruptured and unruptured aneurysms was found(P<0.05). According to 1.5 for the critical value, the incidence of rupture was significant difference (P<0.05) Conclusion:1. BSCTA removed bone thoroughly, and showed excellent image quality in skull base vessels simply. Compared with conventional CTA, BSCTA increased sensitivity in the detection of skull base aneurysms. It can become a normative standard CTA to replace DSA as the preferred method of examination for suspected intracranial aneurysm.2. Aneurysmal morphology of BSCTA had a good correlation with DSA. Its ruptured patterns and location was consistent with the DSA. D/N value was the strongest correlation, and contained more comprehensive information. It can be the most stable way to describe aneurysm morphology.3. Aneurysmal rupture had little to do with location but aneurysm morphology. Wide-necked aneurysms tend to rupture more easily than the narrow neck aneurysms. Aspect ratio had predictive value on aneurysmal rupture, an aspect ratio of more than 1.5 predicted a higher aneurysmal rupture rate.