An ellipsoid convex enhancement filter for detection of asymptomatic intracranial aneurysm candidates in CAD frameworks. Issue 2 (28th January 2016)

• Record Type: Journal Article
• Authors: Jin, Ze; Arimura, Hidetaka; Kakeda, Shingo; Yamashita, Fumio; Sasaki, Makoto; Korogi, Yukunori
• Is Part Of: Medical physics. Volume 43:Issue 2(2016)
• Page Start: 951
• Page End: 960
• Publication Date: 2016-01-28
• Subjects: biomedical MRI -- blood vessels -- Hessian matrices -- image enhancement -- medical image processing; Clinical applications -- Hemodynamics -- Edge enhancement; Involving electronic [emr] or nuclear [nmr] magnetic resonance, e.g. magnetic resonance imaging -- Biological material, e.g. blood, urine; Haemocytometers -- Digital computing or data processing equipment or methods, specially adapted for specific applications -- Image data processing or generation, in general -- Image enhancement or restoration, e.g. from bit‐mapped to bit‐mapped creating a similar image; computer‐aided diagnosis (CAD) -- unruptured intracranial aneurysm -- magnetic resonance angiography (MRA) -- ellipsoid convex enhancement (ECE) filter; Computer aided diagnosis -- Eigenvalues -- Computer modeling -- Radiologists -- Databases -- Medical image contrast -- Angiography -- Three dimensional image processing -- Magnetic resonance; Medical physics -- Periodicals; Medical physics; Geneeskunde; Natuurkunde; Toepassingen; Biophysics; Periodicals; Periodicals; Electronic journals; 610.153
• DOI: 10.1118/1.4940349
• Languages: English
• ISSNs: 0094-2405

Abstract

Abstract : Purpose: Various kinds of enhancement filters have been developed in computer‐aided diagnostic (CAD) frameworks for asymptomatic intracranial aneurysms in magnetic resonance angiography (MRA). However, many bending or branching portions on vessels are also enhanced by the conventional filters as false positives in 3.0 T MRA, which can visualize smaller vessels compared with 1.5 T MRA. To overcome this problem, this study focused on developing an ellipsoid convex enhancement (ECE) filter, which can selectively enhance aneurysms while reducing false positive contrasts on bending or branching portions on vessels, for detection of asymptomatic intracranial aneurysm candidates in CAD frameworks. Methods: The ECE filter was mathematically designed to enhance various convex regions in the intensity space such as convex aneurysms, in which the ratio of the shortest and longest diameters for aneurysms corresponds to the ratio of reciprocals of the square roots of the first and third eigenvalues of a Hessian matrix. The proposed ECE filter was evaluated by measuring an average contrast for false positive models and free‐response receiver operating characteristic curves between two simple CAD frameworks using the ECE and conventional filters based on a leave‐one‐out‐by‐patient test. MRA images for thirty patients (male: 10, female: 20; age: 48–86 yr, mean: 69.2) with 31 unruptured aneurysms (longest diameter: 2.0–5.5 mm, mean: 3.7 mm) were selected for this study. Results: The average contrast for false positive models was reduced by 51.4% using the ECE filter, compared with the conventional filter for the convex regions with ratios of the shortest and longest diameters less than 0.4. The number of false positives per case was decreased from 41.1 to 22.8 on average at a sensitivity of 87% by using the ECE filter. Conclusions: The ECE filter would be useful for boosting the performance of the CAD framework of asymptomatic intracranial aneurysms by providing higher contrast aneurysms and lower contrast false positives such as bending or branching portions on vessels.