Temporal subtraction CT with nonrigid image registration improves detection of bone metastases by radiologists: results of a large-scale observer study.

To determine whether temporal subtraction (TS) CT obtained with non-rigid image registration improves detection of various bone metastases during serial clinical follow-up examinations by numerous radiologists. Six board-certified radiologists retrospectively scrutinized CT images for patients with history of malignancy sequentially. These radiologists selected 50 positive and 50 negative subjects with and without bone metastases, respectively.

First-in-Human Evaluation of Positron Emission Tomography/Computed Tomography With [F]FB(ePEG12)12-Exendin-4: A Phase 1 Clinical Study Targeting GLP-1 Receptor Expression Cells in Pancreas.

Pancreatic β-cell mass (BCM) has a central importance in the pathophysiology of diabetes mellitus. Recently, pancreatic β-cell-specific imaging, especially positron emission tomography (PET) with exendin-based probes, has emerged for non-invasive evaluation of BCM. We developed a novel exendin-based probe labeled with fluorine-18, [F]FB(ePEG12)12-exendin-4 (F-Ex4) for PET imaging.

Optimization of prediction methods for risk assessment of pathogenic germline variants in the Japanese population.

Predicting pathogenic germline variants (PGVs) in breast cancer patients is important for selecting optimal therapeutics and implementing risk reduction strategies. However, PGV risk factors and the performance of prediction methods in the Japanese population remain unclear. We investigated clinicopathological risk factors using the Tyrer-Cuzick (TC) breast cancer risk evaluation tool to predict BRCA PGVs in unselected Japanese breast cancer patients (n = 1,995).

Quantitative and qualitative evaluation of sequential PET/MRI using a newly developed mobile PET system for brain imaging.

Purpose: To evaluate the clinical feasibility of a newly developed mobile PET system with MR-compatibility (flexible PET; fxPET), compared with conventional PET (cPET)/CT for brain imaging.

Methods: Twenty-one patients underwent cPET/CT with subsequent fxPET/MRI using F-FDG. As qualitative evaluation, we visually rated image quality of MR and PET images using a four-point scoring system.

Diffusion-weighted imaging of uterine adenomyosis: Correlation with clinical backgrounds and comparison with malignant uterine tumors.

Aim: To elucidate correlation between signal intensity on diffusion-weighted images (SI-DWI) and clinical backgrounds for uterine adenomyosis and to compare SI-DWI of adenomyosis and malignant uterine tumors.

Methods: This study examined 46 adenomyosis patients diagnosed using magnetic resonance imaging and 25 patients with surgically confirmed malignant uterine myometrial tumor. First, adenomyosis cases were classified visually into high-intensity and low-intensity groups based on the SI-DWI compared with that of normal uterine myometrium.

Feasibility and mid- to long-term results of endovascular treatment for portal vein thrombosis after living-donor liver transplantation.

Purpose: We aimed to evaluate mid- to long-term results of endovascular treatment for portal vein thrombosis (PVT) after living-donor liver transplantation (LDLT).

Methods: Thirty cases (14 males, 16 females; age range, 0.67-65 years) who underwent endovascular treatment including thrombolysis, angioplasty, stent placement, and/or collateral embolization for PVT after LDLT from 2001 to 2017 were retrospectively reviewed.

Qualitative and Quantitative Assessment of Nonlocal Means Reconstruction Algorithm in a Flexible PET Scanner.

Flexible PET (fxPET) was designed to fit existing MRI systems. The newly modified nonlocal means (NLM) algorithm is combined with the 3D dynamic row-action maximum likelihood algorithm (DRAMA). We investigated qualitative and quantitative acceptability of fxPET images reconstructed by modified NLM compared with whole-body (WB) PET/CT images and conventional 3D DRAMA reconstruction alone.

Influence of Asthma Onset on Airway Dimensions on Ultra-high-resolution Computed Tomography in Chronic Obstructive Pulmonary Disease.

Purpose: Asthma onset before the age of 40 years is associated with distinct clinical manifestations in chronic obstructive pulmonary disease (COPD) patients, but its morphologic features remain unestablished. This study aimed to explore airway morphology in COPD patients with asthma onset before 40 years of age using ultra-high-resolution computed tomography (U-HRCT), which allows a more accurate quantitation of the lumen and the wall in smaller airways than using conventional CT.

Materials And Methods: Clinical data of 500 consecutive patients undergoing full inspiratory U-HRCT (1024×1024 matrix and 0.

Signal Intensity and Volume of Pituitary and Thyroid Glands in Preterm and Term Infants.

Background: Hypothalamic-pituitary-thyroid (HPT) maturation has not been extensively evaluated using neonatal MRI, even though both structures are visualized on MRI.

Hypothesis: That signal intensity and volume of pituitary and thyroid (T) glands on MRI in neonates may be interrelated.

Study Type: Retrospective.

Early and late effects of electroconvulsive therapy associated with different temporal lobe structures.

Recent studies examining electroconvulsive therapy (ECT) have reported that early sessions can induce rapid antidepressant and antipsychotic effects, and the early termination of ECT was reported to increase the risk of relapse. We hypothesized that different neural mechanisms associated with the therapeutic effects of ECT may be involved in the different responses observed during the early and late periods of ECT treatment. We investigated whether these antidepressant and antipsychotic effects were associated with temporally and spatially different regional gray matter volume (GMV) changes during ECT.

Adaptive Voxel Matching for Temporal CT Subtraction.

Temporal subtraction (TS) technique calculates a subtraction image between a pair of registered images acquired from the same patient at different times. Previous studies have shown that TS is effective for visualizing pathological changes over time; therefore, TS should be a useful tool for radiologists. However, artifacts caused by partial volume effects degrade the quality of thick-slice subtraction images, even with accurate image registration.

Synthesis and characterization of a novel F-labeled 2,5-diarylnicotinamide derivative targeting orexin 2 receptor.

Orexin 2 receptor (OXR) is thought to play an important role in the arousal-promoting function, but its distribution and function in the pathophysiology of orexin-mediated disorders remains to be fully elucidated. In the present study, we synthesized and characterized a novel F-labeled 2,5-diarylnicotinamide (DAN) derivative as a potential positron emission tomography (PET) probe for imaging of OXR. In binding experiments, [F]DAN-1 selectively bound to OXR.

Evaluation of Malignant Breast Lesions Using High-resolution Readout-segmented Diffusion-weighted Echo-planar Imaging: Comparison with Pathology.

Purpose: We aimed to investigate the performance of high resolution-diffusion-weighted imaging (HR-DWI) using readout-segmented echo-planar imaging in visualizing malignant breast lesions and evaluating their extent, using pathology as a reference.

Methods: This retrospective study included patients who underwent HR-DWI with surgically confirmed malignant breast lesions. Two radiologists blinded to the final diagnosis evaluated HR-DWI independently and identified the lesions, measuring their maximum diameters.

Utility of real-time image fusion technology in ultrasonography-guided fiducial marker implantation for stereotactic body radiation therapy for liver tumors.

Background: Ultrasonography (US) is useful when implanting fiducial markers in the liver. However, the implant position is sometimes lost. Recently, real-time image fusion technology (Volume Navigation [V-navi]; GE Healthcare, Milwaukee, WI, USA) has been introduced as a technique for using images from different modalities, and its utility for fiducial marker implantation has been hypothesized.

Background parenchymal enhancement and its effect on lesion detectability in ultrafast dynamic contrast-enhanced MRI.

Purpose: Background parenchymal enhancement (BPE) often affects interpretation of dynamic contrast-enhanced (DCE) MRI. There is limited evidence that reduced BPE is a feature of ultrafast DCE (UF-DCE) MRI. We aimed to evaluate the effect of BPE levels on lesion detectability on UF-DCE MRI in comparison with conventional DCE MRI.

Distinguishing intrahepatic mass-forming biliary carcinomas from hepatocellular carcinoma by computed tomography and magnetic resonance imaging using the Bayesian method: a bi-center study.

Objectives: To determine imaging hallmarks for distinguishing intrahepatic mass-forming biliary carcinomas (IMBCs) from hepatocellular carcinoma (HCC) and to validate their diagnostic ability using Bayesian statistics.

Methods: Study 1 retrospectively identified clinical and imaging hallmarks that distinguish IMBCs (n = 41) from HCC (n = 247) using computed tomography (CT) and magnetic resonance imaging (MRI). Study 2 retrospectively assessed the diagnostic ability of these hallmarks to distinguish IMBCs (n = 37) from HCC (n = 111) using Bayesian statistics with images obtained from a different institution.

Bone segmentation on whole-body CT using convolutional neural network with novel data augmentation techniques.

Background: The purpose of this study was to develop and evaluate an algorithm for bone segmentation on whole-body CT using a convolutional neural network (CNN).

Methods: Bone segmentation was performed using a network based on U-Net architecture. To evaluate its performance and robustness, we prepared three different datasets: (1) an in-house dataset comprising 16,218 slices of CT images from 32 scans in 16 patients; (2) a secondary dataset comprising 12,529 slices of CT images from 20 scans in 20 patients, which were collected from The Cancer Imaging Archive; and (3) a publicly available labelled dataset comprising 270 slices of CT images from 27 scans in 20 patients.

Hyperestrogenism on 18F-FDG PET/CT in a Patient With Estrogen-Producing Ovarian Clear Cell Carcinoma.

A 78-year-old woman was referred to the gynecologic outpatient department because she was suspected of having ovarian cancer based on an imaging study performed during a general medical examination. Further examination using F-FDG PET/CT revealed a bulky mass lesion with low FDG avidity, as well as surprisingly strong bilateral breast radiotracer uptake despite the patient's age. Thus, an estrogen-producing tumor was suspected.

The comparison of high-resolution diffusion weighted imaging (DWI) with high-resolution contrast-enhanced MRI in the evaluation of breast cancers.

Purpose: We sought to investigate the performance of high resolution (HR) diffusion-weighted imaging (DWI) using readout-segmented echo-planar imaging (rs-EPI), compared with high-resolution contrast-enhanced MRI (HR CE-MRI) in terms of morphological accuracy, on the basis of the Breast Imaging and Reporting and Data System (BI-RADS) MRI descriptors and lesion size.

Methods: This retrospective study included the image data of 94 patients with surgically confirmed malignant breast lesions who had undergone high resolution diffusion-weighted imaging (HR-DWI) and HR CE-MRI. Two radiologists blinded to the final diagnosis independently identified the lesions on HR-DWI, described the morphology of the lesions according to BI-RADS descriptors, and measured lesion size.

A multiparametric approach to diagnosing breast lesions using diffusion-weighted imaging and ultrafast dynamic contrast-enhanced MRI.

Purpose: To evaluate the diagnostic performance of a multiparametric approach to breast lesions including apparent diffusion coefficient (ADC) from diffusion-weighted images (DWI), maximum slope (MS) from ultrafast dynamic contrast enhanced (UF-DCE) MRI, lesion size, and patient's age.

Materials And Methods: In total, 96 lesions (73 malignant, 23 benign) were evaluated. UF-DCE MRI was acquired using a prototype 3D-gradient-echo volumetric interpolated breath-hold examination (VIBE) with compressed sensing.

Acceleration of 2D-MR fingerprinting by reducing the number of echoes with increased in-plane resolution: a volunteer study.

Objective: To compare the absolute values and repeatability of magnetic resonance fingerprinting (MRF) with 3000 and 1500 echoes/slice acquired in 41 s and 20 s (MRF3k and MRF1.5k, respectively).

Materials And Methods: MRF3k and MRF1.

[MRI Connecting Functions and Anatomy: A New Bridge for Radiotherapy].

Advances in medical devices have allowed the use of CT, MRI, and PET-CT for the diagnosis of tumors and the detailed evaluation of the extent of lesions. For several decades, CT has been established as the gold standard modality for the treatment planning of radiotherapy, while MRI has emerged as a tool to evaluate the functional characteristics of tumors without radiation exposure. To further optimize precision radiation therapy, we should consider how functional images can be used in the workflow for radiation therapy.