Influence of Pitch on Surface Dose Distribution and Image Noise of Computed Tomography Scans.

This study evaluated the effect of pitch on 256-slice helical computed tomography (CT) scans. Cylindrical water phantoms (CWP) were measured using axial and helical scans with various pitch values. The surface dose distributions of CWP were measured, and reconstructed images were obtained using filtered back-projection (FBP) and iterative model reconstruction (IMR). The image noise in each reconstructed image was decomposed into a baseline component and another component that varied along the z-axis. The baseline component of the image noise was highest at the center of the reconstructed image and decreased toward the edges. The normalized 2D power spectra for each pitch were almost identically distributed. Furthermore, the ratios of the 2D power spectra for IMR and FBP at different pitch values were obtained. The magnitudes of the components varying along the z-axis were smallest at the center of the reconstructed image and increased toward the edge. The ratios of the 3D power spectra on the fx axis for IMR and FBP at different pitch values were obtained. The results showed that the effect of the pitch was related to the component that varied along the z-axis. Furthermore, the pitch had a smaller effect on IMR than on FBP.

Radiation Dose Reduction for Computed Tomography Localizer Radiography Using an Ag Additional Filter.

OBJECTIVE: This study aimed to assess the potential of an Ag additional filter attached to the bow tie filter of a computed tomography (CT) scanner to reduce the radiation dose in CT localizer radiography. METHODS: Radiation doses in CT localizer radiography with Cu and Ag additional filters were evaluated based on dose measurements and Monte Carlo simulations. Image quality evaluations of an adult torso phantom were performed, and the automatic exposure control performance was evaluated in terms of the water-equivalent thickness estimated from CT localizer radiographs. RESULTS: With the Ag additional filter, effective doses were approximately 72% to 75% lower than those with the Cu additional filter. The image quality and water-equivalent thickness with the Ag additional filter were similar to those with the Cu additional filter. CONCLUSIONS: The Ag additional filter helped significantly reduce radiation doses in CT localizer radiography while maintaining image quality and performance.

Clinical efficacy of lamotrigine and changes in the dosages of concomitantly used psychotropic drugs in Alzheimer's disease with behavioural and psychological symptoms of dementia: a preliminary open-label trial.

AIM: We investigated the clinical efficacy and changes in the dosages of concomitantly used psychotropic drugs in lamotrigine therapy in Alzheimer's disease with behavioural and psychological symptoms of dementia (BPSD). METHODS: This study was a 16-week, preliminary open-label trial. The subjects were 40 inpatients. The outcome measures assessed were BPSD and cognitive function. BPSD was assessed with the Neuropsychiatric Inventory (NPI) and cognitive function was assessed with the Mini-Mental State Examination. The changes in the dosages of concomitant psychotropic drugs were also assessed. RESULTS: Although the mean changes from baseline NPI scores and the two NPI subscales (anxiety and irritability) were significantly lower within the lamotrigine therapy group, no significant differences were found when we compared the lamotrigine therapy group to the control group. The mean decrease from baseline on the NPI agitation subscale, however, was significantly greater in the lamotrigine therapy group than in the control group (P < 0.05). Furthermore, the mean decrease from baseline in the diazepam-equivalent dose was significantly greater in the lamotrigine therapy group than in the control group (P < 0.05). CONCLUSIONS: The results of this study suggest that the administration of lamotrigine to patients with severe Alzheimer's disease with BPSD may be effective and may make it possible to avoid increasing the dosage of antipsychotic medications prescribed to elderly patients.

A naturalistic comparison study of the efficacy and safety of intramuscular olanzapine, intramuscular haloperidol, and intramuscular levomepromazine in acute agitated patients with schizophrenia.

OBJECTIVE: This study was a comparative investigation of the clinical efficacy and safety of intramuscular (IM) olanzapine, IM haloperidol, and IM levomepromazine in acute agitated patients with schizophrenia. METHODS: The subjects were 122 inpatients. Their clinical symptoms were assessed using Positive and Negative Syndrome Scale Excited Component (PANSS-EC), PANSS, and Agitation-Calmness Evaluation Scale, and their safety were assessed using the Abnormal Involuntary Movement Scale, Barnes Akathisia Rating Scale (BARS), and Drug-induced Extrapyramidal Symptoms Scale (DIEPSS). RESULTS: The mean changes from baseline on the PANSS-EC, Agitation-Calmness Evaluation Scale, Abnormal Involuntary Movement Scale, BARS, and DIEPSS scores were significantly better in both IM olanzapine and IM levomepromazine than in IM haloperidol. Of these, the mean changes from baseline on the BARS and DIEPSS scores were significantly better in IM olanzapine than in IM levomepromazine. The mean change from baseline on the PANSS positive score was significantly better in both IM olanzapine and IM haloperidol than in IM levomepromazine. CONCLUSIONS: The results of this study suggest the possibility that the anti-agitation effects of IM olanzapine and IM levomepromazine are more rapid than those of IM haloperidol. No worsening of EPS was observed. Our results also suggest that compared with IM levomepromazine, IM olanzapine is safer and affords greater improvement in symptoms.

Relationship between the plasma concentration of paliperidone and the clinical and drug-induced extrapyramidal symptoms in elderly patients with schizophrenia.

OBJECTIVE: We investigated the relationship between the plasma concentration of paliperidone (PAL) and clinical and drug-induced extrapyramidal symptoms (EPS) in elderly patients with schizophrenia. METHODS: In this study, 15 patients with schizophrenia receiving risperidone were switched to PAL and treated for 12 weeks. Their clinical symptoms were assessed using the Positive and Negative Syndrome Scale and the Clinical Global Impression-Severity of Illness Scale. Their EPS were assessed using the Drug-induced EPS Scale, Abnormal Involuntary Movement Scale, and Barnes Akathisia Scale at baseline and 12 weeks. Plasma concentrations were measured by the liquid chromatography-mass spectrometry/mass spectrometry method. RESULTS: The results revealed that there were significant correlations between the plasma concentration of PAL and improved Positive and Negative Syndrome Scale total, negative, and general psychopathology scores (p<0.05). However, the efficacy did not improve linearly with plasma level. No significant correlations were found between the PAL plasma concentration and the mean change from baseline in the Drug-induced EPS Scale total score, Barnes Akathisia Scale, or Abnormal Involuntary Movement Scale. CONCLUSIONS: The results of this research suggested that, in elderly patients, although none of an increased plasma concentration of PAL, a worsening of EPS, or an increase in prolactin level occurs, linear clinical efficacy may not be obtained.

The influence of switching from risperidone to paliperidone on the extrapyramidal symptoms and cognitive function in elderly patients with schizophrenia: a preliminary open-label trial.

OBJECTIVE: This study was to evaluate the effects on clinical symptoms and cognitive function of switching the treatment of elderly patients with schizophrenia from risperidone to paliperidone (PAL). METHODS: This study was a 12-weeks, preliminary open-label trial. The subjects were 17 inpatients. Their extrapyramidal symptoms (EPS) were assessed using the Drug-Induced Extrapyramidal Symptoms Scale (DIEPSS), Abnormal Involuntary Movement Scale (AIMS), and Barnes Akathisia Scale (BAS), and their cognitive function was assessed using the Brief Assessment Cognition in Schizophrenia: Japanese language version (BACS-J), and their clinical symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS) and Clinical Global Impression-Severity of illness scale (CGI-S) at the 0 and 12 weeks. RESULTS: The DIEPSS and BAS significantly improved after switching from risperidone to PAL. Furthermore, improvement was found on AIMS. The mean change from baseline in z-score of the digit sequencing task was significantly increased. All items on the PANSS and CGI-S were not significant; however, changes in some cognitive function were correlated with changes in EPS. CONCLUSIONS: The results of this study suggest the possibility that switching elderly patients from risperidone to PAL may have improved pre-existing EPS, and may also have helped improve working memory.

Aorta and main pulmonary artery segmentation using stacked U-Net and localization on non-contrast-enhanced computed tomography images.

BACKGROUND: The contact between the aorta, main pulmonary artery (MPA), main pulmonary vein, vena cava (VC), and esophagus affects segmentation of the aorta and MPA in non-contrast-enhanced computed tomography (NCE-CT) images. PURPOSE: A two-stage stacked U-Net and localization of the aorta and MPA were developed for the segmentation of the aorta and MPA in NCE-CT images. METHODS: Normal-dose NCE-CT images of 24 subjects with chronic thromboembolic pulmonary hypertension (CTEPH) and low-dose NCE-CT images of 100 subjects without CTEPH were used in this study. The aorta is in contact with the ascending aorta (AA) and MPA, the AA with the VC, the aortic arch (AR) with the VC and esophagus, and the descending aorta (DA) with the esophagus. These contact surfaces were manually annotated. The contact surfaces were quantified using the contact surface ratio (CSR). Segmentation of the aorta and MPA in NCE-CT images was performed by localization of the aorta and MPA and a two-stage stacked U-Net. Localization was performed by extracting and processing the trachea and main bronchus. The first stage of the stacked U-Net consisted of a 2D U-Net, 2D U-Net with a pre-trained VGG-16 encoder, and 2D attention U-Net. The second stage consisted of a 3D U-Net with four input channels: the CT volume and three segmentation results of the first stage. The model was trained and tested using 10-fold cross-validation. Segmentation of the entire volume was evaluated using the Dice similarity coefficient (DSC). Segmentation of the contact area was also assessed using the mean surface distance (MSD). The statistical analysis of the evaluation underwent a multi-comparison correction. CTEPH and non-CTEPH cases were classified based on the vessel diameters measured from the segmented MPA. RESULTS: For the noncontact surfaces of AA, the MSD of stacked U-Net was 0.31 ± 0.10 mm (p < 0.05) and 0.32 ± 0.13 mm (p < 0.05) for non-CTEPH and CTEPH cases, respectively. For contact surfaces with a CSR of 0.4 or greater in AA, the MSD was 0.52 ± 0.23 mm (p < 0.05), and 0.68 ± 0.29 mm (p > 0.05) for non-CTEPH and CTEPH cases, respectively. MSDs were lower than those of 2D and 3D U-Nets for contact and noncontact surfaces; moreover, MSDs increased slightly with larger CSRs. However, the stacked U-Net achieved MSDs of approximately 1 pixel for a wide contact surface. The area under the receiver operating characteristic curve for CTEPH and non-CTEPH classification using the right main pulmonary artery (RMPA) diameter was 0.97 (95% confidence interval [CI]: 0.94-1.00). CONCLUSIONS: Segmentation of the aorta and MPA on NCE-CT images were affected by vascular and esophageal contact. The application of stacked U-Net and localization techniques for non-CTEPH and CTEPH cases mitigated the impact of contact, suggesting its potential for diagnosing CTEPH.

Study of the efficacy and safety of switching from risperidone to paliperidone in elderly patients with schizophrenia.

AIM: We investigated the clinical efficacy and safety of switching to paliperidone (PAL) in elderly schizophrenia patients receiving risperidone. METHODS: The subjects were 27 inpatients who had been diagnosed with schizophrenia according to the DSM-IV. The patient's clinical symptoms were assessed using the Positive and Negative Syndrome Scale and the Clinical Global Impression-Severity of Illness Scale, and their safety was assessed using the Drug-induced Extrapyramidal Symptoms Scale, bodyweight, body mass index, and laboratory tests. We also investigated patient satisfaction using the Drug Attitude Inventory, a subjective outcome measure. RESULTS: No significant differences in clinical symptom improvement efficacy were seen between the PAL-switching group and the control group. The mean changes from baseline on the Drug-induced Extrapyramidal Symptoms Scale total score, Drug Attitude Inventory score, and prolactin level were significantly greater in the PAL-switching group than in the control group. Furthermore, patients with PAL needed less biperiden, even though they had similar risperidone-equivalent daily dosages to the control group. CONCLUSIONS: The results of this study suggest that switching elderly patients from risperidone to PAL may result in superior safety and patient satisfaction, and may also make it possible to reduce the dosage of biperiden.

The influence of switching from haloperidol decanoate depot to risperidone long-acting injection on the clinical symptoms and cognitive function in schizophrenia.

OBJECTIVE: This study was a comparative investigation of the effects on clinical symptoms and cognitive function of switching the treatment of schizophrenia patients from haloperidol decanoate depot to risperidone long-acting injection (RLAI) compared with a control group that continued receiving haloperidol decanoate depot. METHODS: This study was a 24-week, non-randomized, non-double blind, open-label trial. The subjects' clinical symptoms were assessed using the Positive and Negative Syndrome Scale, and their cognitive function was assessed using the Wisconsin Card Sorting Test: Keio Version to assess executive function and the St. Marianna University School of Medicine's Computerized Memory Test to assess memory and concentration at 0 and 24 weeks. RESULTS: The mean change from baseline in the number of categories achieved at the second stage of the Wisconsin Card Sorting Test: Keio Version was significantly greater in the RLAI group than in the control group. The mean changes from baseline in the individual St. Marianna University School of Medicine's Computerized Memory Tests were significantly greater in the RLAI group than in the control group. The RLAI group needed a lower dosage of biperiden compared with the control group, even though they had similar risperidone-equivalent daily dosages. CONCLUSION: The results of this study suggest the possibility that switching from haloperidol decanoate depot to RLAI may improve cognitive function including memory, executive function, motor processing function, and attention.

The relationship between the plasma concentration of blonanserin, and its plasma anti-serotonin 5-HT(2A) activity/anti-dopamine D2 activity ratio and drug-induced extrapyramidal symptoms.

AIMS: Blonanserin is a second-generation antipsychotic that was developed in Japan. We investigated the relationships between plasma concentration, the plasma anti-5-HT(2A) activity/anti-D2 activity (S/D) ratio and extrapyramidal symptoms (EPS) in blonanserin dosing. METHODS: The subjects were 29 outpatients with schizophrenia. We assessed EPS using the Drug-Induced Extrapyramidal Symptoms Scale (DIEPSS). The plasma concentrations were measured by high performance liquid chromatography, and the plasma anti-D2 and anti-5-HT(2A) activities were measured by [³H]-spiperone and [³H]-ketanserin radioreceptor assays. RESULTS: The results revealed that there were significant correlations between both the plasma concentration and the DIEPSS total score (P<0.05). A negative correlative tendency was found between the S/D ratio and the DIEPSS total score. Furthermore, the plasma concentrations were divided into a low plasma concentration group and a high plasma concentration group, and the S/D ratios were divided into a low S/D ratio group and a high S/D ratio group. We then compared each group based on the DIEPSS total scores. The score in the high plasma concentration-low S/D ratio group was significantly higher than in the high plasma concentration-high S/D ratio, low plasma concentration-high S/D ratio and low plasma concentration-low S/D ratio groups (P<0.05 for all). CONCLUSIONS: These findings indicate that the incidence of EPS during treatment with blonanserin is mainly determined by plasma concentration, but the incidence of EPS may be inhibited when anti-5HT(2A) activity is predominant over anti-D2 activity.