Optimization of Block Sequential Regularized Expectation Maximization Reconstruction Parameters for Striatal SPECT Using a Ring-Type Semiconductor SPECT/CT System.

This phantom study aimed to optimize the noise-suppression parameter (β) and the edge-preservation parameter (γ) values in the block sequential regularized expectation maximization (BSREM) reconstruction method for I-2-β-carbomethoxy-3β-(4-iodophenyl)--(3-fluoropropyl)nortropane striatal SPECT using a ring-type cadmium-zinc-telluride camera. We used a striatum phantom filled with an I solution, with adjusted concentrations in the left and right caudate and left and right putamen. The phantom was scanned for 120 min using the StarGuide system, and 20-min SPECT data were extracted from the total acquisition.

Effect of dental metal prostheses and its metal artefacts on the incidence of nodular overcorrection on PET/CT images: a comparison between silicon photomultiplier and photomultiplier tube PET.

Objectives: Positron emission tomography (PET) images are reconstructed using computed tomography (CT)-based attenuation correction, which may cause artefactual errors due to CT artefacts. This study aimed to investigate the effects of metallic dental prostheses and metal artefacts on the incidence of nodular overcorrection in PET/CT images of the oral cavity in patients with head and neck tumours.

Methods: We retrospectively reviewed the F-18 fluorodeoxyglucose PET/CT images of 27 and 20 patients using silicon photomultiplier (SiPM) and photomultiplier tube (PMT) PET, respectively.

[Impact of Sweep Motion in a Full-ring Semiconductor SPECT/CT System on Image Quality: Evaluation through Phantom Experiments].

Purpose: StarGuide (GE HealthCare, Haifa, Israel), a full-ring SPECT/CT system using Cadmium Zinc Telluride (CZT) technology, allows detectors to perform a pendulum motion (sweep) during SPECT acquisition. It offers two sweep modes: continuous and step and shoot, and we investigated the impact of different sweep modes on spatial resolution and image uniformity.

Methods: Spatial resolution was evaluated using the full width half maximum (FWHM) of line source images.

[Investigation of the Optimal Parameters for Block Sequential Regularized Expectation Maximization (BSREM) Reconstruction in Bone SPECT Using a Ring-type Semiconductor SPECT/CT].

Purpose: This research aims to optimize the block sequential regularized expectation maximization (BSREM) reconstruction in bone single photon emission computed tomography (SPECT) images using a ring-type SPECT/computed tomography (CT) system in terms of image quality and accuracy of quantitative evaluation.

Methods: SPECT images were acquired using a ring-type SPECT/CT and from a SIM bone phantom containing a 99m-Tc solution. BSREM parameters were assessed with coefficient of variation (CV), recovery coefficient (RC), contrast noise ratio (CNR), standardized uptake value max (SUVmax), and its root mean square error (RMSE).

[Spatial Resolution and Uniformity of a Full-ring CZT SPECT/CT System: Comparison with a Conventional Anger-type SPECT/CT Instrument].

Purpose: StarGuide (GE HealthCare, Haifa, Israel) is a full-ring SPECT/CT system based on Cadmium Zinc Telluride (CZT) technology. In this study, we aimed to compare the image quality of this CZT-based SPECT/CT to a conventional Anger-type SPECT/CT system (NM/CT 870 DR, 870DR; GE HealthCare).

Methods: Tomographic sensitivity was calculated by recording the total number of counts detected during tomographic acquisition for a point source.

The utility of customised tissue probability maps and templates for patients with idiopathic normal pressure hydrocephalus: a computational anatomy toolbox (CAT12) study.

Background: Disproportionately enlarged subarachnoid space hydrocephalus (DESH) is one of the neuroradiological characteristics of idiopathic normal pressure hydrocephalus (iNPH), which makes statistical analyses of brain images difficult. This study aimed to develop and validate methods of accurate brain segmentation and spatial normalisation in patients with DESH by using the Computational Anatomy Toolbox (CAT12).

Methods: Two hundred ninety-eight iNPH patients with DESH and 25 healthy controls (HCs) who underwent cranial MRI were enrolled in this study.

Verification of the effect of data-driven brain motion correction on PET imaging.

Introduction: Brain positron emission tomography/computed tomography (PET/CT) scans are useful for identifying the cause of dementia by evaluating glucose metabolism in the brain with F-18-fluorodeoxyglucose or Aβ deposition with F-18-florbetaben. However, since imaging time ranges from 10 to 30 minutes, movements during the examination might result in image artifacts, which interfere with diagnosis. To solve this problem, data-driven brain motion correction (DDBMC) techniques are capable of performing motion corrected reconstruction using highly accurate motion estimates with high temporal resolution.

A case report of forensic personal identification by transposed teeth and dental treatment marks using multidetector row computed tomography.

Using postmortem computed tomography (CT) images, we achieved personal identification of a body using transposed teeth and dental treatment marks. Transposition of teeth is a rare malpositioning anomaly. CT images can clarify the malpositioning of the teeth's roots, which is difficult to discern from gross observation of the dentition.

Improvement of Imaging Conditions to Improve the Detection Rate of Head and Neck Cancer by Positron Emission Tomography/Computed Tomography Examination.

Positron emission tomography (PET)/computed tomography (CT) has improved sensitivity and resolution using silicon photomultiplier as a photosensor. Previously, only a fixed setting was available for the shooting time of 1 bed, but now, the shooting time can be changed for each bed. Time can be shortened or extended depending on the target area.

Impact of atrial fibrillation on the cognitive decline in Alzheimer's disease.

Background: Atrial fibrillation (AF) is a strong risk factor for Alzheimer's disease (AD) independent of ischemic stroke. However, the clinicopathological impact of AF on the severity of AD has not been well elucidated. We aimed to investigate the clinical differences between dementia patients with AF and those without AF by means of imaging data.

Diagnostic Accuracy of Liver Damage Based on Postmortem Computed Tomography Findings in High-Energy Trauma.

The liver is an organ that is frequently injured by blunt trauma. In clinical medicine, contrast-enhanced computed tomography (CT) is useful for diagnosing liver damage. However, detection of liver injury is difficult with postmortem CT (PMCT) that does not use contrast media.

High diagnostic accuracy for lymph node metastasis of oral squamous cell carcinoma using PET/CT with a silicon photomultiplier.

Objective: The higher sensitivity of the new-generation positron emission tomography/computed tomography (PET/CT) with silicon photomultiplier (SiPM) may increase false-positive rates in detecting metastatic lymph nodes (LNs). This study aimed to clarify the usefulness of the SiPM PET scanner in diagnosing LN metastasis of oral squamous cell carcinoma (SCC).

Methods: We retrospectively reviewed consecutive F-18 fluorodeoxyglucose PET/CT images of 39 SCC patients using SiPM PET and 31 SCC patients using non-SiPM PET.

Defining the Optimal Method for Measuring Metabolic Tumor Volume on Preoperative F-Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography as a Prognostic Predictor in Patients With Pancreatic Ductal Adenocarcinoma.

Objectives: Metabolic tumor volume (MTV) on F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) is a promising prognostic predictor in pancreatic ductal adenocarcinoma (PDAC). However, the optimal segmentation method and threshold value to determine MTV for PDAC are still unclear. We explored the optimal method and threshold value for the prognostic value of MTV measured on pre-treatment F-FDG-PET/CT.

Echolalia in patients with primary progressive aphasia.

Objective: This study aimed to examine echolalia and its related symptoms and brain lesions in primary progressive aphasia (PPA).

Methods: Forty-five patients with PPA were included: 19 nonfluent/agrammatic variant PPA (nfvPPA), 5 semantic variant PPA, 7 logopenic variant PPA, and 14 unclassified PPA patients. We detected echolalia in unstructured conversations.

[Examination of Optimal Window Size and Acquisition Time of Respiratory-gated PET Image: Phantom Study with a SiPM-based PET/CT Scanner].

Purpose: This phantom study aimed to determine the optimal acquisition window size for phase-based respiratory gating in silicon photomultiplier (SiPM)-based fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) and its acquisition time in respiratory-gated imaging with the optimal window size.

Methods: Images of a moving NEMA IEC Body Phantom Set with hot spheres were acquired. First, the tumor volume and the maximum standardized uptake value (SUV) of images reconstructed using a different window size were evaluated to define the optimal window size.

Voxel-Based Morphometry Reveals a Correlation Between Bone Mineral Density Loss and Reduced Cortical Gray Matter Volume in Alzheimer's Disease.

: Decreased bone mineral density (BMD) was associated with poorer cognitive function and increased risk of Alzheimer's disease (AD). However, objective evidence for the relationship between osteoporosis and AD in humans has not been extensively described. : We aimed to evaluate the relationships between BMD and the cortical volumes of brain regions vulnerable to AD; hippocampus, parahippocampal gyrus, precuneus, posterior cingulate, and angular gyrus, using voxel-based morphometry (VBM), to investigate the association between bone loss and AD.

Hypoperfusion in the posterior cingulate cortex is associated with lower bone mass density in elderly women with osteopenia and Alzheimer's disease.

Accelerated bone loss is closely associated with Alzheimer's disease (AD), but the relationship between bone mineral density (BMD) and imaging markers of neurodegeneration remains uncertain. We examined the effect of low bone mass (osteopenia) on regional cerebral blood flow (rCBF) in patients with AD (n = 19) and non-demented aging (n = 12). We enrolled 31 female outpatients diagnosed with osteopenia (age ≥ 65 years) who had both a single-photon emission computed tomography brain scan and dual-energy X-ray absorptiometry bone scan taken at their initial investigation.

A systematic performance evaluation of head motion correction techniques for 3 commercial PET scanners using a reproducible experimental acquisition protocol.

Purposes: Subject's motion during brain PET scan degrades spatial resolution and quantification of PET images. To suppress these effects, rigid-body motion correction systems have been installed in commercial PET scanners. In this study, we systematically compare the accuracy of motion correction among 3 commercial PET scanners using a reproducible experimental acquisition protocol.

[Motion-frozen Imaging by Gated Myocardial Perfusion Single Photon Emission Computed Tomography Using Multi-focus Fan Beam Collimator in Thallium-201 Study].

Purpose: This study aimed to evaluate the statistical noise of motion-frozen (MF) image generated by gated myocardial perfusion single photon emission computed tomography (SPECT) imaging using IQ · SPECT and to determine the optimal acquisition and reconstruction parameters for MF image using IQ · SPECT.

Methods: A movement cardiac phantom and static cardiac phantom were used to acquire the MF images. The acquisition times used were different in 8 and 16 frames per R-R interval, and varying reconstruction parameters (subset and iteration) were used.

On the Utility of MIBG SPECT/CT in Evaluating Cardiac Sympathetic Dysfunction in Lewy Body Diseases.

Background: Abnormal cardiac uptake of 123I-metaiodobenzylguanidine (123I-MIBG) is a diagnostic marker of Lewy body diseases (LBDs), e.g., Parkinson's disease (PD) and dementia with Lewy bodies (DLB).

Clinical characteristics of idiopathic normal pressure hydrocephalus with Lewy body diseases.

Background: Comorbidity of idiopathic normal pressure hydrocephalus and neurodegenerative diseases presents a diagnostic challenge. The aim of this study was to elucidate the clinical features of iNPH patients who are possibly comorbid with Lewy body diseases.

Methods: In this study, we retrospectively analyzed the records of consecutive 127 patients with definite idiopathic normal pressure hydrocephalus.

Brain and whole body distribution of N-isopropyl-4-iodoamphetamine (I-123) in humans: comparison of radiopharmaceuticals marketed by different companies in Japan.

Objective: Iodine-123 (123I)-labeled N-isopropyl-4-iodoamphetamine (IMP) has been used as a cerebral blood flow (CBF) tracer for single-photon emission computed tomography (SPECT). An autoradiographic (ARG) method has been developed for the quantitation of CBF by IMP and SPECT. Two IMPs (IMPA and IMPB) produced by different radiopharmaceutical companies are marketed in Japan.