[Changes in FDG-PET Images of Small Lung and Liver Masses Caused by the Deep Learning-based Time-of-flight Processing].

Purpose: The deep learning time-of-flight (DL-ToF) aims to replicate the ToF effects through post-processing, applying deep learning-based enhancement to PET images. This study evaluates the effectiveness of DL-ToF using a chest-abdomen phantom that simulates human anatomical structures.

Methods: The 3 DL-ToF intensities (Low-DL-ToF: LDL, Middle-DL-ToF: MDL, High-DL-ToF: HDL) were adopted for the PET image of the chest-abdomen phantom.

Assessment of cerebral perfusion in moyamoya disease with dynamic pseudo-continuous arterial spin labeling using a variable repetition time scheme with optimized background suppression.

Purpose: Accurate assessment of cerebral perfusion in moyamoya disease is necessary to determine the indication for treatment. We aimed to investigate the usefulness of dynamic PCASL using a variable TR scheme with optimized background suppression in the evaluation of cerebral perfusion in moyamoya disease.

Methods: We retrospectively analyzed the images of 24 patients (6 men and 18 women, mean age 31.

Effect of Saturation Pulse Duration and Power on pH-weighted Amide Proton Transfer Imaging: A Phantom Study.

Purpose: Amide proton transfer (APT) imaging may detect changes in tissues' pH based on the chemical exchange saturation transfer (CEST) phenomenon, and thus it may be useful for identifying the penumbra in ischemic stroke patients. We investigated the effect of saturation pulse duration and power on the APT effect in phantoms with different pH values.

Methods: Five samples were prepared from a 1:10 solution of egg-white albumin in phosphate-buffered saline at pH 6.

A deep learning-based approach for the diagnosis of adrenal adenoma: a new trial using CT.

Objective: To develop and validate deep convolutional neural network (DCNN) models for the diagnosis of adrenal adenoma (AA) using CT.

Methods: This retrospective study enrolled 112 patients who underwent abdominal CT (non-contrast, early, and delayed phases) with 107 adrenal lesions (83 AAs and 24 non-AAs) confirmed pathologically and with 8 lesions confirmed by follow-up as metastatic carcinomas. Three patients had adrenal lesions on both sides.

Continuous bed motion in a silicon photomultiplier-based scanner provides equivalent spatial resolution and image quality in whole body PET images at similar acquisition times using the step-and-shoot method.

This study investigated the spatial resolution and image quality of the continuous bed motion (CBM) method in a sensitive silicon photomultiplier (SiPM)-based positron emission tomography (PET)/computed tomography (CT) system compared with the traditional step-and-shoot (SS) method. Siemens Biograph Vision was used in this study. Data acquisition using the SS method was performed for 3 min per bed.

Optimization of 4D-MR angiography based on superselective pseudo-continuous arterial spin labeling combined with CENTRA-keyhole and view-sharing (4D-S-PACK) for vessel-selective visualization of the internal carotid artery and vertebrobasilar artery systems.

Purpose: This study investigated the optimal labeling position and gradient moment for 4D-MR angiography based on superselective pseudo-continuous arterial spin labeling combined with CENTRA-keyhole and view-sharing (4D-S-PACK) for vessel-selective flow visualization of the internal carotid artery (ICA) and vertebrobasilar artery (VBA) systems.

Methods: Seven healthy volunteers were scanned with a 3.0 T MR scanner.

Radiology- and gene-based risk stratification in small renal cell carcinoma: A preliminary study.

Purpose: Most small renal cell carcinomas (small RCCs) will remain indolent after detection, but some stage I RCCs still metastasize. There are no risk-stratification imaging factors that could be used to identify poor-prognosis patients based on genomic profiling. Here, we evaluated the relationships between imaging parameters and RNA expressions in small RCC and attempted to identify imaging factors that could be used as effective biomarkers.

A comparison among gamma distribution, intravoxel incoherent motion, and mono-exponential models with turbo spin-echo diffusion-weighted MR imaging in the differential diagnosis of orofacial lesions.

Objectives: To compare the gamma distribution (GD), intravoxel incoherent motion (IVIM), and monoexponential (ME) models in terms of their goodness-of-fit, correlations among the parameters, and the effectiveness in the differential diagnosis of various orofacial lesions.

Methods: A total of 85 patients underwent turbo spin-echo diffusion-weighted imaging with six b-values. The goodness-of-fit of three models was assessed using Akaike Information Criterion.

Optimization of the refocusing flip angle in the characterization of cerebrospinal fluid dynamics using multi-spin echo acquisition cine imaging (MUSACI).

Purpose: Multi-spin echo acquisition cine imaging (MUSACI) is a method used for cerebrospinal fluid (CSF) dynamics imaging based on the proton phase dispersion and flow void using 3D multi-spin echo imaging. In a previous study, the refocusing flip angle of MUSACI was set at a constant 80°. We conducted the present study to investigate the preservation the CSF signal intensity even in a long echo train and improve the ability to visualize CSF movement by modifying the refocusing flip angle in MUSACI.

The application of a gamma distribution model to diffusion-weighted images of the orofacial region.

Objectives: This study evaluated the correlation among the diffusion-derived parameters obtained by monoexponential (ME), intravoxel incoherent motion (IVIM) and γ distribution (GD) models and compared these parameters among representative orofacial tumours.

Methods: Ninety-two patients who underwent 1.5 T MRI including diffusion-weighted imaging were included.

Correction to: Development of a new phantom simulating extracellular space of tumor cell growth and cell edema for diffusion-weighted magnetic resonance imaging.

The original version of this article unfortunately contained a mistake. Second column of "Cell edema" should read as.

Development of a new phantom simulating extracellular space of tumor cell growth and cell edema for diffusion-weighted magnetic resonance imaging.

Objective: A phantom for diffusion-weighted imaging is required to standardize quantitative evaluation. The objectives were to develop a phantom simulating various cell densities and to evaluate repeatability.

Materials And Methods: The acrylic fine particles with three different diameters were used to simulate human cells.

The reproducibility of measurements using a standardization phantom for the evaluation of fractional anisotropy (FA) derived from diffusion tensor imaging (DTI).

Objectives: It is necessary to standardize the examination procedure and diagnostic criteria of diffusion tensor imaging (DTI). Thus, the purpose of this study was to examine the reproducibility of measurements using a standardization phantom composed of different fibre materials with different fibre densities (FDs) for the evaluation of fractional anisotropy (FA) derived from DTI.

Materials And Methods: Two types of fibre materials wrapped in heat-shrinkable tubes were used as fibre phantoms.

Visualization of cerebrospinal fluid dynamics using multi-spin echo acquisition cine imaging (MUSACI).

Purpose: To evaluate the visualization of CSF dynamics using the novel method multi-spin echo acquisition cine imaging (MUSACI).

Methods: MUSACI is based on multi-echo volume isotropic turbo spin-echo acquisition (VISTA) with pulse gating. MUSACI images were acquired in 11 healthy volunteers (7 men, 4 women; age range, 24-46 y, mean age, 31.

Estimation of proton density fat fraction of the salivary gland.

Objective: Our first objective was to prove the validity of the six-point Dixon method for estimating the proton density fat fraction (PDFF) of the salivary gland. The second objective was to estimate the salivary gland PDFF using Dixon method to evaluate the pathological conditions.

Methods: At first, 12 volunteers underwent two types of sequences: single-voxel magnetic resonance spectroscopy and the Dixon method and the PDFFs obtained by the two methods were compared.

Comparison of TOF-PET and Bremsstrahlung SPECT Images of Yttrium-90: A Monte Carlo Simulation Study.

Objectives: Yttrium-90 (Y) is a beta particle nuclide used in targeted radionuclide therapy which is available to both single-photon emission computed tomography (SPECT) and time-of-flight (TOF) positron emission tomography (PET) imaging. The purpose of this study was to assess the image quality of PET and Bremsstrahlung SPECT by simulating PET and SPECT images of Y using Monte Carlo simulation codes under the same conditions and to compare them.

Methods: In-house Monte Carlo codes, MCEP-PET and MCEP-SPECT, were employed to simulate images.

Clinical usefulness of the mDIXON Quant the method for estimation of the salivary gland fat fraction: comparison with MR spectroscopy.

Objective: To estimate the fat fraction (FF) in the salivary glands (SGs) by the mDIXON method and the H-MR spectroscopy (MRS) method, and to compare the results.

Methods: 16 healthy volunteers were enrolled. mDIXON Quant and MRS (point-resolved spectroscopy: PRESS) with a single TE were employed to measure the FF in the parotid gland (PG) and submandibular gland (SMG).

Analysis of the influence of In on Y-bremsstrahlung SPECT based on Monte Carlo simulation.

Objective: Y-ibritumomab tiuxetan (Zevalin) which is used for the treatment of malignant lymphomas can be used for SPECT imaging based on bremsstrahlung from Y beta particles. However, gamma rays emitted by In, which is administered to evaluate the indication for the treatment, contaminate the Y bremsstrahlung images. Our objective is to investigate the influence of In on the Y SPECT images using Monte Carlo simulation.

Glycosaminoglycan chemical exchange saturation transfer in human lumbar intervertebral discs: Effect of saturation pulse and relationship with low back pain.

Purpose: To evaluate the dependence of saturation pulse power and duration on glycosaminoglycan chemical exchange saturation transfer (gagCEST) imaging and assess the degeneration of human lumbar intervertebral discs (IVDs) using this method.

Materials And Methods: All images were acquired on a 3T magnetic resonance imaging (MRI) scanner. The CEST effects were measured in the glycosaminoglycan (GAG) phantoms with different concentrations.

Evaluation of Iterative Reconstruction Method and Attenuation Correction in Brain Dopamine Transporter SPECT Using an Anthropomorphic Striatal Phantom.

Objectives: The aim of this study was to determine the optimal reconstruction parameters for iterative reconstruction in different devices and collimators for dopamine transporter (DaT) single-photon emission computed tomography (SPECT). The results were compared between filtered back projection (FBP) and different attenuation correction (AC) methods.

Methods: An anthropomorphic striatal phantom was filled with (123)I solutions at different striatum-to-background radioactivity ratios.

Monte Carlo simulation of PET and SPECT imaging of 90Y.

Purpose: Yittrium-90 ((90)Y) is traditionally thought of as a pure beta emitter, and is used in targeted radionuclide therapy, with imaging performed using bremsstrahlung single-photon emission computed tomography (SPECT). However, because (90)Y also emits positrons through internal pair production with a very small branching ratio, positron emission tomography (PET) imaging is also available. Because of the insufficient image quality of (90)Y bremsstrahlung SPECT, PET imaging has been suggested as an alternative.

An anthropomorphic phantom study of brain dopamine transporter SPECT images obtained using different SPECT/CT devices and collimators.

Unlabelled: The aim of this study was to evaluate differences in dopamine transporter SPECT images among different SPECT/CT devices and to determine the most appropriate region of interest (ROI) for semiquantitative evaluation.

Methods: An anthropomorphic striatal phantom was filled with (123)I solutions of different striatum-to-background radioactivity ratios. Data were acquired using 2 SPECT/CT devices equipped with low- to medium-energy general-purpose and low-energy high-resolution (LEHR) collimators.

Influences of reconstruction and attenuation correction in brain SPECT images obtained by the hybrid SPECT/CT device: evaluation with a 3-dimensional brain phantom.

Objectives: The aim of this study was to evaluate the influences of reconstruction and attenuation correction on the differences in the radioactivity distributions in (123)I brain SPECT obtained by the hybrid SPECT/CT device.

Methods: We used the 3-dimensional (3D) brain phantom, which imitates the precise structure of gray matter, white matter and bone regions. It was filled with (123)I solution (20.

Automated measurement of cerebral cortical thickness based on fuzzy membership map derived from MR images for evaluation of Alzheimer's disease.

We have proposed an automated method for three-dimensional (3D) measurement of cerebral cortical thicknesses based on fuzzy membership maps derived from magnetic resonance (MR) images for evaluation of Alzheimer's disease (AD). The cerebral cortical thickness was three-dimensionally measured on each cortical surface voxel by using a localized gradient vector trajectory in a fuzzy membership map. The proposed method could be useful for the 3D measurement of the cerebral cortical thickness on individual cortical surface voxels as an atrophy feature in AD.