Gender difference in relationship between anxiety-related personality traits and cerebral brain glucose metabolism.

Recent functional neuroimaging studies have suggested that specific brain regions might be associated with the formation of anxiety-related personality traits, which are well known to be influenced by gender. Such anxiety-related personality traits are one of the representative predisposing factors for mood and anxiety disorders, whose incidence is also known to be much influenced by gender. However, little is known about the gender differences in brain function related to anxiety-related personality traits. The aim of the present study was to examine gender-related differences in the pattern of the relationships between an anxiety-related personality trait and cerebral brain glucose metabolism. Regional brain glucose metabolism was measured using [(18)F]fluorodeoxyglucose positron emission tomography in 102 healthy subjects (65 males and 37 females). An anxiety-related trait was assessed using the Temperament and Character Inventory dimension Harm Avoidance (HA). HA was negatively correlated with glucose metabolism in the anterior portion of the ventromedial prefrontal cortex (vmPFC) in females but not in males. The anterior vmPFC may be a possible neural target for the prevention or therapy of emotional disorders, especially in females.

Regional brain cerebral glucose metabolism and temperament: a positron emission tomography study.

Personality, and in particular temperament, is thought to have a biological basis. In the present study, the relationships between regional brain glucose metabolism and temperament have been investigated. Regional brain glucose metabolism was measured using [18F] fluorodeoxyglucose positron emission tomography in 31 healthy subjects. Temperament was assessed using the Temperament and Character Inventory. Temperament dimensions were observed to be significantly correlated with specific brain regions. In particular, novelty seeking was significantly correlated with the superior temporal gyrus, inferior parietal lobule, and the precuneus, which have been reported to be related with impulsiveness, while reward dependence was significantly correlated with the caudate head, which has been shown to be associated with reward processing. The various aspects of temperament may have biological bases in the specific brain regions. The accumulation of results from studies of this kind should provide further evidence connecting personality traits with their biological bases.

[Comparison of activity expression between PET using 68Ge-68Ga line source attenuation correction and PET-CT using CT attenuation correction: impact on emission images].

OBJECTIVES: CT data can be used for both anatomical image and attenuation correction (CTAC) of PET data in PET-CT scanners. The CTAC method is useful for attenuation correction, because the CT scan time is much shorter than the external radionuclide (e.g., (68)Ge) transmission scan time. However, the energy of the X-rays from CT is not monoenergetic and is much lower than that of the external radionuclide source. In this study, we evaluated the differences between emission PET images reconstructed with CT-based and (68)Ge-based attenuation correction. METHODS: CT scans and (68)Ge-Transmission scans were acquired and used for attenuation correction (CTAC, MAC, and SAC). The PET emission scan time was 4 min. CT scans were acquired at 10, 20, 40, 80, and 160 mA. (68)Ge-Transmission scans were acquired at 1, 3, 5, 10, 20, 40, 60, and 300 min. The attenuation-corrected emission image using MAC on a 300 min transmission scan was defined as the reference image. Seven cylinders (30 mm diameter) were filled with (18)F-FDG placed in a heart-liver phantom with simulated pulmonary mass lesions. The PET value [counts/cc] was measured in circular regions of interest (ROI) over the cylindrical mass lesion. Averages [counts/cc], coefficients of variation [C.V.(%)], and ratios of difference [%Diff] from the reference value were calculated for all conditions. RESULTS: In the CT-Transmission, analysis of variance revealed no significant effect of CT current on the average and the C.V. In the (68)Ge-Transmission, the average and the C.V. changed in dependence on the acquisition time. All %Diff using CT-Transmission were small. It was shown that CT-Transmission is more appropriate than (68)Ge-Transmission.

Usefulness of dual 67Ga and 99mTc-sestamibi single-photon-emission CT scanning in the diagnosis of cardiac sarcoidosis.

Cardiac sarcoidosis is potentially fatal and hence requires a precise diagnosis. We performed dual (67)Ga (Ga)-(99m)Tc-sestamibi (Tc) single-photon emission CT (SPECT) scans by superimposing a Ga-SPECT image on the myocardial outline traced with Tc. The usefulness of this imaging technique in the diagnosis of cardiac sarcoidosis was studied. The subjects in this study were 14 patients with sarcoidosis (mean [+/- SD] age, 52 +/- 16 years; 5 men and 9 women). An IV dose of Tc (74 MBq per 2 mL) was injected into patients 72 h after an IV dose of Ga (111 MBq per 3 mL) was injected. The dual SPECT scan was performed 30 min after the Tc dose was administered. The energy used for collection was 93 keV for Ga and 140 keV for Tc. The myocardial outline was successfully traced in all subjects, allowing us to check for myocardial Ga uptake and to identify its location. Abnormal Ga uptake in the myocardium was observed in 9 of the 14 subjects. In seven of these nine subjects, the location of the abnormal myocardial Ga uptake was identical to the location of reduced Tc uptake. Abnormal Ga uptake disappeared in all cases following steroid therapy. Of the five subjects who were free of abnormal Ga uptake, two showed reduced Tc uptake, and these two subjects had been receiving steroid therapy. These results suggest that dual SPECT scanning using Ga and Tc represents a very useful diagnostic imaging technique since it improves the diagnostic capability of Ga-SPECT to allow the highly specific diagnosis of cardiac sarcoidosis.

The neural correlates of mindful awareness: a possible buffering effect on anxiety-related reduction in subgenual anterior cingulate cortex activity.

BACKGROUND: Human personality consists of two fundamental elements character and temperament. Character allays automatic and preconceptual emotional responses determined by temperament. However, the neurobiological basis of character and its interplay with temperament remain elusive. Here, we examined character-temperament interplay and explored the neural basis of character, with a particular focus on the subgenual anterior cingulate cortex extending to a ventromedial portion of the prefrontal cortex (sgACC/vmPFC). METHODS: Resting brain glucose metabolism (GM) was measured using [(18)F] fluorodeoxyglucose positron emission tomography in 140 healthy adults. Personality traits were assessed using the Temperament and Character Inventory. Regions of interest (ROI) analysis and whole-brain analysis were performed to examine a combination effect of temperament and character on the sgACC/vmPFC and to explore the neural correlates of character, respectively. RESULTS: Harm avoidance (HA), a temperament trait (i.e., depressive, anxious, vulnerable), showed a significant negative impact on the sgACC/vmPFC GM, whereas self-transcendence (ST), a character trait (i.e., intuitive, judicious, spiritual), exhibited a significant positive effect on GM in the same region (HA ß = -0.248, p = 0.003; ST: ß = 0.250, p = 0.003). In addition, when coupled with strong ST, individuals with strong HA maintained the sgACC/vmPFC GM level comparable to the level of those with low scores on both HA and ST. Furthermore, exploratory whole-brain analysis revealed a significant positive relationship between ST and sgACC/vmPFC GM (peak voxel at x = -8, y = 32, z = -8, k = 423, Z = 4.41, corrected p (FDR) = 0.030). CONCLUSION: The current findings indicate that the sgACC/vmPFC might play a critical role in mindful awareness to something beyond as well as in emotional regulation. Developing a sense of mindfulness may temper exaggerated emotional responses in individuals with a risk for or having anxiety and depressive disorders.

Stereotactic imaging for radiosurgery: localization accuracy of magnetic resonance imaging and positron emission tomography compared with computed tomography.

Computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) provide complementary information for treatment planning in stereotactic radiosurgery. We evaluated the localization accuracy of MRI and PET compared with CT. Two kinds of phantoms applicable to the Leksell G stereotactic skull frame (Elekta, Tokyo) were developed. Deviations of measured coordinates at target points (x = 50, 100, 150; y = 50, 100, 150) were determined on different axial planes (z = 30-140 for MRI and CT study and Z = 50-120 for PET and CT study). For MRI, the deviations were no more than 0.8 mm in each direction. For PET, the deviations were no more than 2.7 mm. For both imaging modalities studied, accuracy was at or below the imaging resolution (pixel size) and should be considered useful for clinical stereotactic planning purposes.