Voxelwise analysis of simultaneously acquired and spatially correlated F-fluorodeoxyglucose (FDG)-PET and intravoxel incoherent motion metrics in breast cancer.

Purpose: Diffusion-weighted imaging (DWI) and F-fluorodeoxyglucose-positron emission tomography ( F-FDG-PET) independently correlate with malignancy in breast cancer, but the relationship between their structural and metabolic metrics is not completely understood. This study spatially correlates diffusion, perfusion, and glucose avidity in breast cancer with simultaneous PET/MR imaging and compares correlations with clinical prognostics.

Methods: In this Health Insurance Portability and Accountability Act-compliant prospective study, with written informed consent and approval of the institutional review board and using simultaneously acquired FDG-PET and DWI, tissue diffusion (D ), and perfusion fraction (f ) from intravoxel incoherent motion (IVIM) analysis were registered to FDG-PET within 14 locally advanced breast cancers.

Zoomed echo-planar diffusion tensor imaging for MR tractography of the prostate gland neurovascular bundle without an endorectal coil: a feasibility study.

Purpose: The purpose of this study was to assess the feasibility of zoomed echo-planar imaging (EPI) diffusion tensor imaging (DTI) with 2-channel parallel transmission (pTx) for MR tractography of the periprostatic neurovascular bundle (NVB) without an endorectal coil, and to compare its performance to that of conventionally acquired DTI.

Methods: 8 healthy males (28.9 ± 4.

Simultaneous Multislice Accelerated Free-Breathing Diffusion-Weighted Imaging of the Liver at 3T.

Purpose: To perform image quality comparison between accelerated multiband diffusion acquisition (mb2-DWI) and conventional diffusion acquisition (c-DWI) in patients undergoing clinically indicated liver MRI.

Methods: In this prospective study 22 consecutive patients undergoing clinically indicated liver MRI on a 3-T scanner equipped to perform multiband diffusion-weighed imaging (mb-DWI) were included. DWI was performed with single-shot spin-echo echo-planar technique with fat-suppression in free breathing with matching parameters when possible using c-DWI, mb-DWI, and multiband DWI with a twofold acceleration (mb2-DWI).

A pilot study in epilepsy patients using simultaneous PET/MR.

Integrated PET/MR with simultaneous acquisition may improve the identification of pathologic findings in patients. This pilot study evaluated metabolic activity differences between epilepsy patients and healthy controls and directly correlated FDG uptake with MR regional abnormality. Epilepsy patients (n=11) and controls (n=6) were imaged on a whole-body simultaneous PET/MR scanner.

Comparison of the accuracy of PET/CT and PET/MRI spatial registration of multiple metastatic lesions.

Objective: The purpose of this study was to compare the accuracy of the spatial registration of conventional PET/CT with that of hybrid PET/MRI of patients with FDG-avid metastatic lesions.

Subjects And Methods: Thirteen patients with known metastatic lesions underwent FDG PET/CT followed by PET/MRI with a hybrid whole-body system. The inclusion criterion for tumor analysis was spherical or oval FDG-avid tumor clearly identified with both CT and MRI.

Correlation between standardized uptake value and apparent diffusion coefficient of neoplastic lesions evaluated with whole-body simultaneous hybrid PET/MRI.

Objective: The purpose of this study was to assess the correlation between standardized uptake value (SUV) and apparent diffusion coefficient (ADC) of neoplastic lesions in the use of a simultaneous PET/MRI hybrid system.

Subjects And Methods: Twenty-four patients with known primary malignancies underwent FDG PET/CT. They then underwent whole-body PET/MRI.

Long-duration transcutaneous electric acupoint stimulation alters small-world brain functional networks.

Acupuncture, which is recognized as an alternative and complementary treatment in Western medicine, has long shown efficiencies in chronic pain relief, drug addiction treatment, stroke rehabilitation and other clinical practices. The neural mechanism underlying acupuncture, however, is still unclear. Many studies have focused on the sustained effects of acupuncture on healthy subjects, yet there are very few on the topological organization of functional networks in the whole brain in response to long-duration acupuncture (longer than 20 min).

Detection of myocardial ischemia by automated, motion-corrected, color-encoded perfusion maps compared with visual analysis of adenosine stress cardiovascular magnetic resonance imaging at 3 T: a pilot study.

Purpose: The purpose of this study was to compare automated, motion-corrected, color-encoded (AMC) perfusion maps with qualitative visual analysis of adenosine stress cardiovascular magnetic resonance imaging for detection of flow-limiting stenoses.

Materials And Methods: Myocardial perfusion measurements applying the standard adenosine stress imaging protocol and a saturation-recovery temporal generalized autocalibrating partially parallel acquisition (t-GRAPPA) turbo fast low angle shot (Turbo FLASH) magnetic resonance imaging sequence were performed in 25 patients using a 3.0-T MAGNETOM Skyra (Siemens Healthcare Sector, Erlangen, Germany).

Simultaneous CBF and BOLD mapping of high frequency acupuncture induced brain activity.

This study mapped brain activity elicited by high frequency electroacupuncture by simultaneously using blood oxygenation level dependent (BOLD) and cerebral blood flow (CBF) contrasts. Forty subjects participated in the study, in which twenty ones were imaged during electrical acupoint stimulation (EAS) to the left LI4 acupoint at a maximal intensity without pain, and the others were with a minimal-EAS at a just detectible intensity. Both BOLD and CBF data were acquired simultaneously during alternating blocks of rest and stimulation.

Hippocampal magnetization transfer ratio at 3T: validation of automated postprocessing and comparison of quantification metrics.

Background: To investigate the reliability of a novel magnetization transfer ratio (MTR) postprocessing technique for the hippocampus using histogram analysis, and compare results to more established volumetric measurements. This study is conducted in healthy volunteers as a precursor to future applications regarding progressive neurologic diseases, such as Alzheimer's disease.

Methods: Eight healthy subjects were scanned twice with interval of 1 week using quantitative magnetic resonance imaging (MRI).

Optimization of single shot 3D breath-hold non-enhanced MR angiography of the renal arteries.

Background: Cardiac and navigator-gated, inversion-prepared non-enhanced magnetic resonance angiography techniques can accurately depict the renal arteries without the need for contrast administration. However, the scan time and effectiveness of navigator-gated techniques depend on the subject respiratory pattern, which at times results in excessively prolonged scan times or suboptimal image quality. A single-shot 3D magnetization-prepared steady-state free precession technique was implemented to allow the full extent of the renal arteries to be depicted within a single breath-hold.

Inline directionally independent peak velocity evaluation reduces error in peak antegrade velocity estimation in patients referred for cardiac valvular assessment.

Objective: The purpose of this article is to evaluate the utility of a tool in quantifying the peak antegrade velocity when assessing patients with cardiac valvular pathology.

Materials And Methods: Directionally independent peak velocity evaluation (MaxVelocity, Siemens Healthcare) phase-contrast cardiac MRI was performed for 44 patients referred to our institution with a diagnosis or concern for aortic valvular disease or undergoing imaging for thoracic aortic aneurysm. In addition, standard through-plane phase-contrast MR angiography at the level of the aortic valve was performed.

Peripheral arterial disease in a symptomatic diabetic population: prospective comparison of rapid unenhanced MR angiography (MRA) with contrast-enhanced MRA.

Objective: The joint guidelines of the American College of Cardiology and American Heart Association support the use of contrast-enhanced MR angiography (CEMRA) to diagnose the location and degree of stenosis in patients with known or suspected peripheral arterial disease (PAD). The high prevalence of chronic renal impairment in diabetic patients with PAD and the need for high doses of gadolinium-based contrast agents place them at risk for nephrogenic systemic fibrosis. The purpose of our study was to evaluate the accuracy of the rapid technique of quiescent-interval single-shot (QISS) unenhanced MR angiography (MRA) compared with CEMRA for the diagnosis in diabetic patients referred with symptomatic chronic PAD.

Comprehensive brain analysis with automated high-resolution magnetization transfer measurements.

Purpose: To enhance the reliability and spatial resolution of magnetization transfer ratio (MTR) measurements for interrogation of subcortical brain regions with an automated volume of interest (VOI) approach.

Materials And Methods: A 3D magnetization transfer (MT) sequence was acquired using a scan-rescan imaging protocol in nine healthy volunteers. VOI definition masks for the MTR measurements were generated using FreeSurfer and compared to a manual region of interest (ROI) approach.

Assessing low-frequency repetitive transcranial magnetic stimulation with functional magnetic resonance imaging: a case series.

Background And Purpose: This case series assesses the effects of five consecutive days of low-frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) with and without a 6-Hz primer. Although this paper studies able-bodied individuals, similar rTMS protocols are used to facilitate motor recovery in patients with hemiplegia following stroke. However, the cortical mechanisms associated with repeated daily doses of rTMS are not completely understood.

Dual pathways for haptic and visual perception of spatial and texture information.

Segregation of information flow along a dorsally directed pathway for processing object location and a ventrally directed pathway for processing object identity is well established in the visual and auditory systems, but is less clear in the somatosensory system. We hypothesized that segregation of location vs. identity information in touch would be evident if texture is the relevant property for stimulus identity, given the salience of texture for touch.

Incomplete cortical reorganization in macular degeneration.

Purpose: Activity in regions of the visual cortex corresponding to central scotomas in subjects with macular degeneration (MD) is considered evidence for functional reorganization in the brain. Three unresolved issues related to cortical activity in subjects with MD were addressed: Is the cortical response to stimuli presented to the preferred retinal locus (PRL) different from other retinal loci at the same eccentricity? What effect does the role of age of onset and etiology of MD have on cortical responses? How do functional responses in an MD subject's visual cortex vary for task and stimulus conditions?

Methods: Eight MD subjects-four with age-related onset (AMD) and four with juvenile onset (JMD)-and two age-matched normal vision controls, participated in three testing conditions while undergoing functional magnetic resonance imaging (fMRI). First, subjects viewed a small stimulus presented at the PRL compared with a non-PRL control location to investigate the role of the PRL.

An Inexpensive and Programmable RF Transmitter Setup for Two-coil CASL.

An inexpensive and programmable RF transmitter for two-coil continuous arterial spin labeling (CASL) system is presented in this paper. While previous implementations of two-coil CASL require the expensive MR RF instruments, the present design utilizes a low-cost system on chip direct digital synthesizer and a mini-size communication RF power amplifier to generate the labeling RF waveform without sacrificing RF performance. Compared with a single RF channel two-coil CASL approach, this design requires minimal scanner hardware modifications.

Estimating cerebral blood volume with expanded vascular space occupancy slice coverage.

A model for quantifying cerebral blood volume (CBV) based on the vascular space occupancy (VASO) technique and varying the extent of blood nulling yielding task-related signal changes with various amounts of blood oxygenation level-dependent (BOLD) and VASO weightings was previously described. Challenges associated with VASO include limited slice coverage and the confounding inflow of fresh blood. In this work, an approach that extends the previous model to multiple slices and accounts for the inflow effect is described and applied to data from a multiecho sequence simultaneously acquiring VASO, cerebral blood flow (CBF), and BOLD images.