Synchronous neuroendocine liver metastases in comparison to primary pancreatic neuroendocrine tumors on MRI and SSR-PET/CT.

Background: The study aimed to compare and correlate morphological and functional parameters in pancreatic neuroendocrine tumors (pNET) and their synchronous liver metastases (NELM), while also assessing prognostic imaging parameters.

Methods: Patients with G1/G2 pNET and synchronous NELM underwent pretherapeutic abdominal MRI with DWI and 68Ga-DOTATATE/TOC PET/CT were included. ADC (mean, min), SNR_art and SNT_T2 (SNR on arterial phase and on T2) and SUV (max, mean) for three target NELM and pNET, as well as tumor-free liver and spleen (only in PET/CT) were measured.

[Knee cartilage injuries in athletes].

Background: Acute and chronic cartilage injuries are often encountered in professional and recreational athletes. They can compromise the athlete's performance and career and are considered a potential risk factor for early joint degeneration.

Objectives: Incidence of cartilage injury in athletes, understanding of cartilage composition, injury mechanism and suitable diagnostic imaging are summarized and established therapeutic procedures, postoperative imaging including detection of relevant complications and assessment of reasonable indications for follow-up examinations are described.

Multiscale X-ray phase contrast imaging of human cartilage for investigating osteoarthritis formation.

Background: The evolution of cartilage degeneration is still not fully understood, partly due to its thinness, low radio-opacity and therefore lack of adequately resolving imaging techniques. X-ray phase-contrast imaging (X-PCI) offers increased sensitivity with respect to standard radiography and CT allowing an enhanced visibility of adjoining, low density structures with an almost histological image resolution. This study examined the feasibility of X-PCI for high-resolution (sub-) micrometer analysis of different stages in tissue degeneration of human cartilage samples and compare it to histology and transmission electron microscopy.

Convolutional neuronal networks combined with X-ray phase-contrast imaging for a fast and observer-independent discrimination of cartilage and liver diseases stages.

We applied transfer learning using Convolutional Neuronal Networks to high resolution X-ray phase contrast computed tomography datasets and tested the potential of the systems to accurately classify Computed Tomography images of different stages of two diseases, i.e. osteoarthritis and liver fibrosis.

[Update: clinical imaging of cartilage-part 1 : Technical aspects].

Background: In order to answer clinical therapy-oriented questions, reliable and consistent depiction of articular cartilage across technical platforms is necessary.

Materials And Methods: Technical standards and developments in cartilage imaging are summarized based on current literature and experience from clinical daily routine.

Results: Clinical questions that need to be answered relate to cross-sectional extent, depth, differentiating cartilaginous from bony components of a lesion and to the lesion's location within the compartment.

[Update: Clinical imaging of cartilage-part 2 : Aspects helpul in daily clinical practice].

Background: Imaging-based analysis of articular cartilage and its defects as well as the radiologist have to live up to the more and more specific clinical questions arising from increasing experience with cartilage-dedicated therapies.

Materials And Methods: Based on the currently available literature and experience from clinical routine, imaging findings relevant for lesion analysis will be summarized and illustrated by specific pathologies.

Results: Local aspects and topographic distribution of bone marrow edema pattern (BMEP), careful analysis of the cartilage surface and of the subchondral plate as well as the patient's clinical and biomechanical context are essential for image analysis.

Graft Hypertrophy After Third-Generation Autologous Chondrocyte Implantation Has No Correlation With Reduced Cartilage Quality: Matched-Pair Analysis Using T2-Weighted Mapping.

Background: Graft hypertrophy is common after matrix-based autologous chondrocyte implantation (ACI) in the knee joint. However, it is not clear whether graft hypertrophy is a complication or an adjustment reaction in the cartilage regeneration after ACI.

Purpose: To analyze the cartilage quality of the ACI regeneration with graft hypertrophy using T2-weighted mapping.

Identification of Functional Cell Groups in the Abducens Nucleus of Monkey and Human by Perineuronal Nets and Choline Acetyltransferase Immunolabeling.

The abducens nucleus (nVI) contains several functional cell groups: motoneurons of the singly-innervated twitch muscle fibers (SIF) and those of the multiply-innervated muscle fibers (MIF) of the lateral rectus muscle (LR), internuclear neurons (INTs) projecting to the contralateral oculomotor nucleus (nIII) and paramedian tract-neurons (PMT) that receive input from premotor neurons of the oculomotor system and project to the floccular region. In monkey, these cell populations can be delineated by their chemical signature. For correlative clinico-pathological studies the identification of the homologous cell groups in the human nVI are required.

Quantitative Assessment of Degenerative Cartilage and Subchondral Bony Lesions in a Preserved Cadaveric Knee: Propagation-Based Phase-Contrast CT Versus Conventional MRI and CT.

Objective: The aim of this study was to quantitatively assess hyaline cartilage and subchondral bone conditions in a fully preserved cadaveric human knee joint using high-resolution x-ray propagation-based phase-contrast imaging (PBI) CT and to compare the performance of the new technique with conventional CT and MRI.

Materials And Methods: A cadaveric human knee was examined using an x-ray beam of 60 keV, a detector with a 90-mm FOV, and a pixel size of 46 × 46 μm. PBI CT images were reconstructed with both the filtered back projection algorithm and the equally sloped tomography method.

Memory decline accompanies subthreshold amyloid accumulation.

Objective: Extensive cortical β-amyloid (Aβ positivity) has been linked to cognitive decline, but the clinical significance of elevations in Aβ within the negative range is unknown.

Methods: We examined amyloid and cognitive trajectories (memory, executive function) in 142 cognitively normal older individuals enrolled in the Alzheimer's Disease Neuroimaging Initiative who were Aβ-negative at baseline and who had at least 2 [F]-florbetapir PET scans over 3.9 ± 1.

Comparison of multiple tau-PET measures as biomarkers in aging and Alzheimer's disease.

The recent development of tau-specific positron emission tomography (PET) tracers enables in vivo quantification of regional tau pathology, one of the key lesions in Alzheimer's disease (AD). Tau PET imaging may become a useful biomarker for clinical diagnosis and tracking of disease progression but there is no consensus yet on how tau PET signal is best quantified. The goal of the current study was to evaluate multiple whole-brain and region-specific approaches to detect clinically relevant tau PET signal.

Alzheimer Disease Signature Neurodegeneration and APOE Genotype in Mild Cognitive Impairment With Suspected Non-Alzheimer Disease Pathophysiology.

Importance: There are conflicting results claiming that Alzheimer disease signature neurodegeneration may be more, less, or similarly advanced in individuals with β-amyloid peptide (Aβ)-negative (Aβ-) suspected non-Alzheimer disease pathophysiology (SNAP) than in Aβ-positive (Aβ+) counterparts.

Objective: To examine patterns of neurodegeneration in individuals with SNAP compared with their Aβ+ counterparts.

Design, Setting, And Participants: A longitudinal cohort study was conducted among individuals with mild cognitive impairment (MCI) and cognitively normal individuals receiving care at Alzheimer's Disease Neuroimaging Initiative sites in the United States and Canada for a mean follow-up period of 30.

Hard X-ray index of refraction tomography of a whole rabbit knee joint: A feasibility study.

We report results of the computed tomography reconstruction of the index of refraction in a whole rabbit knee joint examined at the photon energy of 51keV. Refraction based images make it possible to delineate the bone, cartilage, and soft tissues without adjusting the contrast window width and level. Density variations, which are related to tissue composition and are not visible in absorption X-ray images, are detected in the obtained refraction based images.

Amyloid negativity in patients with clinically diagnosed Alzheimer disease and MCI.

Objective: To examine the clinical and biomarker characteristics of patients with amyloid-negative Alzheimer disease (AD) and mild cognitive impairment (MCI) from the Alzheimer's Disease Neuroimaging Initiative (ADNI), a prospective cohort study.

Methods: We first investigated the reliability of florbetapir- PET in patients with AD and patients with MCI using CSF-Aβ1-42 as a comparison amyloid measurement. We then compared florbetapir- vs florbetapir+ patients with respect to several AD-specific biomarkers, baseline and longitudinal cognitive measurements, and demographic and clinician report data.

When Absence of Evidence Is Evidence of Absence: Rational Inferences From Absent Data.

Identifying patterns in the world requires noticing not only unusual occurrences, but also unusual absences. We examined how people learn from absences, manipulating the extent to which an absence is expected. People can make two types of inferences from the absence of an event: either the event is possible but has not yet occurred, or the event never occurs.

Understanding 3D TSE Sequences: Advantages, Disadvantages, and Application in MSK Imaging.

Three-dimensional (3D) turbo-spin echo (TSE) sequences have outgrown the stage of mere sequence optimization and by now are clinically applicable. Image blurring and acquisition times have been reduced, and contrast for T1-, T2-, and moderately T2-weighted (or intermediate-weighted) fat-suppressed variants has been optimized. Data on sound-to-noise ratio efficiency and contrast are available for moderately T2-weighted fat-saturated sequence protocols.

Boundary value problem for phase retrieval from unidirectional X-ray differential phase images.

The phase retrieval problem can be reduced to the second order partial differential equation. In order to retrieve the absolute values of the X-ray phase and to minimize the reconstruction artifacts we defined the mixed inhomogeneous boundary condition using available a priori information about the sample. Finite element technique was used to solve the boundary value problem.

Topographic deformation patterns of knee cartilage after exercises with high knee flexion: an in vivo 3D MRI study using voxel-based analysis at 3T.

Objectives: To implement a novel voxel-based technique to identify statistically significant local cartilage deformation and analyze in-vivo topographic knee cartilage deformation patterns using a voxel-based thickness map approach for high-flexion postures.

Methods: Sagittal 3T 3D-T1w-FLASH-WE-sequences of 10 healthy knees were acquired before and immediately after loading (kneeling/squatting/heel sitting/knee bends). After cartilage segmentation, 3D-reconstruction and 3D-registration, colour-coded deformation maps were generated by voxel-based subtraction of loaded from unloaded datasets to visualize cartilage thickness changes in all knee compartments.

[Organ and function preservation in urethral cancer].

Primary urethral carcinomas are rare tumors that can occur both in men and women. Histological patterns of these tumors are mixed, urothelial tumors occur as well as squamous cell tumors or adenocarcinomas.There are different clinical factors that define clinical prognosis, and the 1- and 5-year cancer-free survival is 75% and 54%.

Graft maturation of autologous chondrocyte implantation: magnetic resonance investigation with T2 mapping.

Background: Autologous chondrocyte implantation (ACI) using tissue-engineered cartilage is a successful therapy for full-thickness cartilage lesions in the knee joint. However, in vivo graft maturation is still unclear.

Purpose: The aim of this prospective study was to analyze graft maturation after ACI in the knee using objective T2 mapping in correlation with the clinical outcomes within a 3-year postoperative course.

Cartilage and soft tissue imaging using X-rays: propagation-based phase-contrast computed tomography of the human knee in comparison with clinical imaging techniques and histology.

Objectives: This study evaluates high-resolution tomographic x-ray phase-contrast imaging in whole human knee joints for the depiction of soft tissue with emphasis on hyaline cartilage. The method is compared with conventional computed tomography (CT), synchrotron radiation absorption-based CT, and magnetic resonance imaging (MRI).

Material And Methods: After approval of the institutional review board, 2 cadaveric human knees were examined at an synchrotron institution using a monochromatic x-ray beam of 60 keV, a detector with a 90-mm field of view, and a pixel size of 46 × 46 μm.

Assessment of therapeutic response in ankylosing spondylitis patients undergoing anti-tumour necrosis factor therapy by whole-body magnetic resonance imaging.

Objectives: Multifocal musculoskeletal inflammation is common in ankylosing spondylitis (AS) and is effectively treated by expensive anti-TNF (tumour necrosis factor) therapy. This study evaluated assessment of response by whole-body (WB) MRI compared with clinical assessment in AS patients during etanercept therapy.

Methods: Ten patients with AS underwent a 12-month therapy with etanercept.

Graft hypertrophy of matrix-based autologous chondrocyte implantation: a two-year follow-up study of NOVOCART 3D implantation in the knee.

Purpose: Graft hypertrophy is a major complication in the treatment for localized cartilage defects with autologous chondrocyte implantation (ACI) using periosteal flap and its further development, Novocart (a matrix-based ACI procedure). The aim of the present study is to investigate individual criteria for the development of graft hypertrophy by NOVOCART 3D implantation of the knee in the post-operative course of 2 years.

Methods: Forty-one consecutive patients with 44 isolated cartilage defects of the knee were treated with NOVOCART 3D implants.