Identification of atrophy of the subgenual anterior cingulate cortex, in particular the subcallosal area, as an effective auxiliary means of diagnosis for major depressive disorder

Akira Niida,¹ Richi Niida,² Hiroshi Matsuda,³ Takashi Inada,⁴ Makoto Motomura,⁵ Akihiko Uechi<sup>6

1</sup>Department of Radiology, Nanbu Hospital, Itoman City, Okinawa, ²Department of Psychiatry, Nanto Clinic, Urasoe City, Okinawa, ³Department of Nuclear Medicine, Saitama Medical University International Medical Center, Hidaka City, Saitama, ⁴Department of Psychiatry, Kai Clinic, Naha City, Okinawa, ⁵Department of Human Sciences, University of the Ryukyu, Nakagami County, Okinawa, ⁶Cognitive Neuroscience Research Project, Kansai Gaidai University, Hirakata City, Osaka, Japan

Background: Despite being a very common psychiatric disorder, physicians often have difficulty making a diagnosis of major depressive disorder (MDD) because, without established diagnostic criteria, they have to depend on interviews with patients and observation to assess psychiatric symptoms. However, previous researchers have reported that magnetic resonance imaging (MRI) scans identify morphological changes in the brains of patients with MDD, which inspired us to hypothesize that assessment of local changes in the brain using voxel-based morphometry would serve as an auxiliary diagnostic method for MDD. Therefore, we focused on the VSRAD® plus (voxel-based specific regional analysis system for Alzheimer’s disease), a diagnostic support system for use in early Alzheimer’s disease, which allowed us to identify regional atrophy in the brain easily based on images obtained from MRI scans.
Methods: The subjects were 75 patients with MDD, 15 with bipolar disorder, and 30 healthy subjects, aged 54–82 years. First, 1.5 T MRI equipment was used to scan three-dimensional T₁-weighted images for the individual subjects, and the imaged data were analyzed by VSRAD advance (voxel-based morphometric software developed for diagnosis of early Alzheimer’s disease). The efficacy of the equipment for diagnosis of MDD was evaluated based on the distribution of atrophy in the subgenual anterior cingulate cortex (sACC) on the z-score map obtained.
Results: No significant difference in atrophy was noted between the left and right sACCs. The VSRAD advance used in the present study was more effective than the VSRAD plus for diagnosis of MDD, with a sensitivity of 90.7%, specificity of 86.7%, accuracy of 89.5%, a positive predictive value of 94.4%, and a negative predictive value of 78.8%. In particular, atrophy was observed in the subcallosal area of the sACC.
Conclusion: The identification of atrophy in the sACC, in particular of the subcallosal area, with the use of updated voxel-based morphometric software proved to be effective as an auxiliary diagnostic method for MDD.

Keywords: major depressive disorder, magnetic resonance imaging, subgenual anterior cingulate cortex, voxel-based morphometry, VSRAD