Spatial-temporal perfusion patterns of the human liver assessed by pseudo-continuous arterial spin labeling MRI.

Purpose: To investigate the capabilities of a modern pseudo-continuous arterial spin labeling (PCASL) technique for non-invasive assessment of the temporal and spatial distribution of the liver perfusion in healthy volunteers on a clinical MR system at 3T.

Materials And Methods: A 2D-PCASL multi-slice echo planar imaging sequence was adapted to the specific conditions in liver: a) labeling by PCASL was optimized to the flow characteristics in the portal vein, b) background suppression was applied for reduction of motion related artifacts, c) post labeling delays (PLDs) were varied over a large range (0.7-3.

Fast non-enhanced abdominal examination protocols in PET/MRI for patients with neuroendocrine tumors (NET): comparison to multiphase contrast-enhanced PET/CT.

Purpose: To evaluate fast non-enhanced protocols for abdominal PET/MRI in comparison to contrast-enhanced PET/CT with somatostatin receptor (SSR)-specific radiotracers regarding effectiveness of lesion detection in NET patients.

Methods: This was a retrospective analysis of 29 patients (12 male, 57 ± 13 years) who underwent PET/CT and subsequently PET/MRI at the same day. Two readers evaluated independently four PET/MRI setups: (I) PET + T2 Half Fourier Acquisition Single Shot Turbo Spin Echo (T2 HASTE), (II) PET + T2 HASTE + T2-weighted spin-echo sequence (T2 TSE), III) PET + T2 HASTE + Diffusion Weighted Imaging (DWI) and (IV) PET + T2 HASTE + T2 TSE + DWI.

Simultaneous multislice diffusion-weighted imaging in whole-body positron emission tomography/magnetic resonance imaging for multiparametric examination in oncological patients.

Objectives: The aim of this study was to compare the diagnostic performance of simultaneous multislice diffusion-weighted imaging (DWI-SMS) with that of standard DWI (DWI-STD) in whole-body 3-T PET/MRI examination protocols in oncological patients.

Methods: In a phantom study, we evaluated the apparent diffusion coefficients (ADC) from the two techniques. In ten volunteers, we assessed ADC values in different organs.

Characterization of Severe Arterial Phase Respiratory Motion Artifact on Gadoxetate Disodium-Enhanced MRI - Assessment of Interrater Agreement and Reliability.

Purpose:  To assess the interrater agreement and reliability of experienced abdominal radiologists in the characterization and grading of arterial phase gadoxetate disodium-related respiratory motion artifact on liver MRI.

Materials And Methods:  This prospective multicenter study was initiated by the working group for abdominal imaging within the German Roentgen Society (DRG), and approved by the local IRB of each participating center. 11 board-certified radiologists independently reviewed 40 gadoxetate disodium-enhanced liver MRI datasets.

Scan time reduction in diffusion-weighted imaging of the pancreas using a simultaneous multislice technique with different acceleration factors: How fast can we go?

Objectives: To investigate the feasibility of simultaneous multislice-accelerated diffusion-weighted imaging (sms-DWI) of the pancreas with different acceleration factors and its influence on image quality, acquisition time and apparent diffusion coefficients (ADCs) in comparison to conventional sequences.

Methods: DWI of the pancreas was performed at 1.5T in ten healthy volunteers and 20 patients with sms-accelerated echo-planar DWI using two different sms-acceleration factors of 2 and 3 (sms2/3-DWI).

SUV-quantification of physiological lung tissue in an integrated PET/MR-system: Impact of lung density and bone tissue.

Purpose: The aim of the study was to investigate the influence of lung density changes as well as bone proximity on the attenuation correction of lung standardized uptake values (SUVs).

Methods And Materials: 15 patients with mostly oncologic diseases were examined in 18F-FDG-PET/CT and subsequently in a fully integrated PET/MR scanner. From each PET dataset acquired in PET/MR, four different PET reconstructions were computed using different attenuation maps (μ-maps): i) CT-based μ-map (gold standard); ii) CT-based μ-map in which the linear attenuation coefficients (LAC) of the lung tissue was replaced by the lung LAC from the MR-based segmentation method; iii) based on reconstruction ii), the LAC of bone structures was additionally replaced with the LAC from the MR-based segmentation method; iv) the vendor-provided MR-based μ-map (segmentation-based method).

Imaging of Cholangiocarcinoma.

Cholangiocarcinoma (CC) is the second most common primary hepatobiliary tumour, and it is increasing in incidence. Imaging characteristics, behaviour, and therapeutic strategies in CC differ significantly, depending on the morphology and location of the tumour. In cross-sectional imaging, CCs can be classified according to the growth pattern (mass-forming, periductal infiltrating, intraductal) and the location (intrahepatic, perihilar, extrahepatic/distal).

[Dentogene Focus as a Rare Cause of Necrotizing Fasciitis].

 We elaborate the case of a 72-year-old patient who presented with a painful swelling of the lower jaw in the emergency unit.  In the clinical examination and the CT scan, a widespread cervical emphysema was found which raised suspicion for the presence of a necrotizing fasciitis of the head and neck due to aerogenic infection. Close spatial vicinity to the teeth of the left upper and lower jaw was present, so that the necrotizing fasciitis was assumed to be odontogenic.

Diagnosing Lung Nodules on Oncologic MR/PET Imaging: Comparison of Fast T1-Weighted Sequences and Influence of Image Acquisition in Inspiration and Expiration Breath-Hold.

Objective: First, to investigate the diagnostic performance of fast T1-weighted sequences for lung nodule evaluation in oncologic magnetic resonance (MR)/positron emission tomography (PET). Second, to evaluate the influence of image acquisition in inspiration and expiration breath-hold on diagnostic performance.

Materials And Methods: The study was approved by the local Institutional Review Board.

Feasibility of self-gated isotropic radial late-phase MR imaging of the liver.

Objective: To evaluate feasibility of a 3D-isotropic self-gated radial volumetric interpolated breath-hold examination (VIBE) for late-phase MRI of the liver.

Material And Methods: 70 patients were included and underwent liver MRI at 1.5 T.

Diffusion-weighted imaging in the assessment of prostate cancer: Comparison of zoomed imaging and conventional technique.

Purpose: To compare reduced field-of-view (zoomed) diffusion-weighted imaging (DWI) and conventional DWI in the evaluation of prostate cancer with respect to lesion detection, image quality and alignment accuracy.

Material And Methods: The study was carried out in accordance with the Declaration of Helsinki and was approved by the institutional review board. Image data of 29 histology-proven prostate cancer lesions in 15 patients were evaluated.

Scan time minimization in hepatic diffusion-weighted imaging: evaluation of the simultaneous multislice acceleration technique with different acceleration factors and gradient preparation schemes.

Objective: To evaluate simultaneous multislice (sms) accelerated diffusion-weighted imaging (DWI) of the liver in comparison to conventional sequences.

Materials And Methods: Ten volunteers underwent DWI of the liver at 1.5 T.

Simultaneous multislice diffusion-weighted MRI of the liver: Analysis of different breathing schemes in comparison to standard sequences.

Purpose: To systematically evaluate image characteristics of simultaneous-multislice (SMS)-accelerated diffusion-weighted imaging (DWI) of the liver using different breathing schemes in comparison to standard sequences.

Materials And Methods: DWI of the liver was performed in 10 healthy volunteers and 12 patients at 1.5T using an SMS-accelerated echo planar imaging sequence performed with respiratory-triggering and free breathing (SMS-RT, SMS-FB).

Imaging of HCC-Current State of the Art.

Early diagnosis of hepatocellular carcinoma (HCC) is crucial for optimizing treatment outcome. Ongoing advances are being made in imaging of HCC regarding detection, grading, staging, and also treatment monitoring. This review gives an overview of the current international guidelines for diagnosing HCC and their discrepancies as well as critically summarizes the role of magnetic resonance imaging (MRI) and computed tomography (CT) techniques for imaging in HCC.

Optimized Fast Dynamic Contrast-Enhanced Magnetic Resonance Imaging of the Prostate: Effect of Sampling Duration on Pharmacokinetic Parameters.

Objective: The aim of this study was to evaluate the effect of sampling duration on pharmacokinetic parameters from dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) and their diagnostic accuracy regarding the detection of potentially malignant prostate lesions.

Materials And Methods: Sixty-six consecutive male patients (mean [SD] age, 65.4 [10.

Recurrent pyogenic cholangitis as a differential diagnosis in biliary tract diseases.

Recurrent Pyogenic Cholangitis (RPC) or Primary Hepatolithiasis is a common disease of the biliary tract in Asia, whereas it is usually not seen in Europeans. With increasing global mobility, the disease will be encountered in Europe more frequently, too. It should therefore be considered as a differential diagnosis in patients from endemic countries with recurrent symptoms of cholestasis/cholangitis and bile duct dilations, strictures and hepatolithiasis.

Feasibility of CAIPIRINHA-Dixon-TWIST-VIBE for dynamic contrast-enhanced MRI of the prostate.

Purpose: To evaluate the feasibility of a CAIPIRINHA-Dixon-TWIST (CDT)-VIBE sequence for improving image quality and temporal resolution in dynamic contrast-enhanced MRI (DCE-MRI) of the prostate.

Material And Methods: 44 male patients (age 63.9 ± 8.

Assessment of metastatic colorectal cancer with hybrid imaging: comparison of reading performance using different combinations of anatomical and functional imaging techniques in PET/MRI and PET/CT in a short case series.

Purpose: The purpose was to investigate the diagnostic performance of different combinations of anatomical and functional imaging techniques in PET/MRI and PET/CT for the evaluation of metastatic colorectal cancer lesions.

Methods: Image data of 15 colorectal cancer patients (FDG-PET/CT and subsequent FDG-PET/MRI) were retrospectively evaluated by two readers in five reading sessions: MRI (morphology) alone, MRI/diffusion-weighted MRI (DWI), MRI/PET, MRI/DWI/PET; and PET/CT. Diagnostic performance of lesion detection with each combination was assessed in general and organ-based.

Combined unsupervised-supervised classification of multiparametric PET/MRI data: application to prostate cancer.

Multiparametric medical imaging data can be large and are often complex. Machine learning algorithms can assist in image interpretation when reliable training data exist. In most cases, however, knowledge about ground truth (e.

Multiparametric analysis of bone marrow in cancer patients using simultaneous PET/MR imaging: Correlation of fat fraction, diffusivity, metabolic activity, and anthropometric data.

Background: To analyze the regional composition of bone marrow (BM) in correlation with metabolic activity and diffusivity using simultaneous positron emission tomography (PET)/MRI.

Methods: Retrospective analysis of 18F-FDG-PET/MR scans of 110 patients was performed. A three-dimensional gradient-echo sequence with Dixon-based fat-water separation was used for fat quantification.

Segmentation-based attenuation correction in positron emission tomography/magnetic resonance: erroneous tissue identification and its impact on positron emission tomography interpretation.

Objectives: The objective of this study was to evaluate the frequency and characteristics of artifacts in segmentation-based attenuation correction maps (μ-maps) of positron emission tomography/magnetic resonance (PET/MR) and their impact on PET interpretation and the standardized uptake value (SUV) quantification in normal tissue and lesions.

Materials And Methods: The study was approved by the local institutional review board. Attenuation maps of 100 patients with PET/MR and preceding PET/computed tomography examination were retrospectively inspected for artifacts (tracers: 2-deoxy-2-[¹⁸F]fluoro-D-glucose (¹⁸F-FDG), ¹¹C-Choline, ⁶⁸Ga-DOTATOC, ⁶⁸Ga-DOTATATE, ¹¹C-Methionine).

Diffusion-weighted imaging during MR-guided radiofrequency ablation of hepatic malignancies: analysis of immediate pre- and post-ablative diffusion characteristics.

Background: Previous studies have shown a benefit of magnetic resonance (MR)-diffusion-weighted imaging (DWI) for follow-up after liver radiofrequency (RF) ablation. However, no data are available concerning acute changes of DWI characteristics immediately after RF ablation.

Purpose: To analyze and compare the MR-diffusion characteristics of pre-interventional hepatic malignancies and the ablation zone during successful MR-guided RF ablation.