James R. Clarke

Comparison of long and short axis quantification of left ventricular volume parameters by cardiovascular magnetic resonance, with ex-vivo validation

BackgroundThe purpose of the study was to compare the accuracy and evaluation time of quantifying left ventricular (LV), left atrial (LA) volume and LV mass using short axis (SAX) and long axis (LAX) methods when using cardiovascular magnetic resonance (CMR).Materials and methodsWe studied 12 explanted canine hearts and 46 patients referred for CMR (29 male, age 47 ± 18 years) in a clinical 1.5 T CMR system, using standard cine sequences. In standard short axis stacks of various slice thickness values in dogs and 8 mm slice thickness (gap 2 mm) in patients, we measured LV volumes using reference slices in a perpendicular, long axis orientation using certified software. Volumes and mass were also measured in six radial long axis (LAX) views.LV parameters were also assessed for intra- and inter-observer variability. In 24 patients, we also analyzed reproducibility and evaluation time of two very experienced (> 10 years of CMR reading) readers for SAX and LAX.ResultsIn the explanted dog hearts, there was excellent agreement between ex vivo data and LV mass and volume data as measured by all methods for both, LAX (r2 = 0.98) and SAX (r2 = 0.88 to 0.98). LA volumes, however, were underestimated by 13% using the LAX views. In patients, there was a good correlation between all three assessed methods (r2 ≥ 0.95 for all). In experienced clinical readers, left-ventricular volumes and ejection fraction as measured in LAX views showed a better inter-observer reproducibility and a 27% shorter evaluation time.ConclusionWhen compared to an ex vivo standard, both, short axis and long axis techniques are highly accurate for the quantification of left ventricular volumes and mass. In clinical settings, however, the long axis approach may be more reproducible and more time-efficient. Therefore, the rotational long axis approach is a viable alternative for the clinical assessment of cardiac volumes, function and mass.

Alternative Imaging Modalities in Ischemic Heart Failure (AIMI-HF) IMAGE HF Project I-A: study protocol for a randomized controlled trial

BackgroundIschemic heart disease (IHD) is the most common cause of heart failure (HF); however, the role of revascularization in these patients is still unclear. Consensus on proper use of cardiac imaging to help determine which candidates should be considered for revascularization has been hindered by the absence of clinical studies that objectively and prospectively compare the prognostic information of each test obtained using both standard and advanced imaging.Methods/DesignThis paper describes the design and methods to be used in the Alternative Imaging Modalities in Ischemic Heart Failure (AIMI-HF) multi-center trial. The primary objective is to compare the effect of HF imaging strategies on the composite clinical endpoint of cardiac death, myocardial infarction (MI), cardiac arrest and re-hospitalization for cardiac causes.In AIMI-HF, patients with HF of ischemic etiology (n = 1,261) will follow HF imaging strategy algorithms according to the question(s) asked by the physicians (for example, Is there ischemia and/or viability?), in agreement with local practices. Patients will be randomized to either standard (SPECT, Single photon emission computed tomography) imaging modalities for ischemia and/or viability or advanced imaging modalities: cardiac magnetic resonance imaging (CMR) or positron emission tomography (PET). In addition, eligible and consenting patients who could not be randomized, but were allocated to standard or advanced imaging based on clinical decisions, will be included in a registry.DiscussionAIMI-HF will be the largest randomized trial evaluating the role of standard and advanced imaging modalities in the management of ischemic cardiomyopathy and heart failure. This trial will complement the results of the Surgical Treatment for Ischemic Heart Failure (STICH) viability substudy and the PET and Recovery Following Revascularization (PARR-2) trial. The results will provide policy makers with data to support (or not) further investment in and wider dissemination of alternative ‘advanced’ imaging technologies.Trial registrationNCT01288560

Neuroanatomy of coprolalia in Tourette syndrome using functional magnetic resonance imaging

OBJECTIVE To determine the neural substrates of phonic tics in Tourette syndrome (TS) using functional magnetic resonance imaging (fMRI) and compare with a proposed tic-generating network (TGN). PATIENTS One with TS and one normal control. METHODS fMRI scans were obtained on the TS patient during which numerous unsuppressed phonic tics occurred and, along with the scanner noise, were recorded on audiotape. The control underwent the same functional MRI sequence but mimicked the tics within predetermined, on-off time blocks. Fuzzy clustering (FC) methods were used to generate the activation maps. RESULTS The TS patient and control showed fMRI activation in the left middle frontal gyrus and right precentral gyrus. The TS patient also had activity in the caudate nucleus, cingulate gyrus, cuneus, left angular gyrus, left inferior parietal gyrus, and occipital gyri. CONCLUSIONS fMRI, using an FC analysis, is a viable technique for studying TS patients with phonic tics. These results give further support to the hypothesis of a tic-generating circuit model. Further studies are required to confirm our data.

Atypical brown fat distribution in young males demonstrated on PET/CT.

The development of PET/CT has led to the recognition that metabolically active fat, referred to as “brown fat,” can accumulate FDG and represents a possible source of false-positive scans in oncology patients. Numerous reports have described the typical appearance of brown fat, which most commonly presents as neck and paravertebral uptake in young female patients. Other described sites of uptake include the mediastinum and retroperitoneum. We present examples of 2 cases of atypical diffuse brown fat uptake seen in the subcutaneous fat of the thighs, abdomen, and pelvis. Both of these patients were young men and did not show uptake in the typical supraclavicular and neck fat. Although rare in our experience, knowledge of this condition may prevent misinterpretation of this finding as an infiltrative condition of the skin, such as lymphoma.

Single-shot steady-state free precession can detect myocardial edema in patients: A feasibility study

To demonstrate the ability of single‐shot, T2/T1 weighted steady‐state free precession (SSFP) to detect myocardial edema in patients with an acute myocardial infarction.

Apparatus for small angle x‐ray scattering measurements of polymer deformation

We present an apparatus which is capable of small‐angle x‐ray scattering studies of polymer deformation at strain rates ranging from 49.6 μm/s to less than 0.033 μm/s and temperatures ranging from room (≊22 °C) to 120 °C. The system also includes a load cell for measuring the force applied to the sample and a symmetric stretching system to keep the sample centered in the x‐ray beam.

Ethics in Radiology: Wait Lists Queue Jumping

Education in ethics is a requirement for all Royal College residency training programs as laid out in the General Standards of Accreditation for residency programs in Canada. The ethical challenges that face radiologists in clinical practice are often different from those that face other physicians, because the nature of the physician-patient interaction is unlike that of many other specialties. Ethics education for radiologists and radiology residents will benefit from the development of teaching materials and resources that focus on the issues that are specific to the specialty. This article is intended to serve as an educational resource for radiology training programs to facilitate teaching ethics to residents and also as a continuing medical education resource for practicing radiologists. In an environment of limited health care resources, radiologists are frequently asked to expedite imaging studies for patients and, in some respects, act as gatekeepers for specialty care. The issues of wait lists, queue jumping, and balancing the needs of individuals and society are explored from the perspective of a radiologist.

1022 Single-shot SSFP can identify myocardial edema in patients

Methods A standard SSFP sequence with a large (31) number of dummy pulses combined with a linear encoding scheme was used to achieve strong T2/T1 image contrast during the acquisition of the central lines of k-space. All imaging data was acquired in a single heart beat. In a second heartbeat, coil profile information was acquired which was used during postprocessing to remove signal inhomogeneities caused by the coil sensitivity, as described previously [1]. Imaging parameters were as follows: TR/TE/flip angle = 3.0 ms/1.5 ms/90°; matrix = 78 × 128; Field-of-view = 267 × 380 mm2; GRAPPA parallel imaging scheme; iPAT factor = 2. This study was carried out in 6 patients (mean age = 55 years) referred to our centre for myocardial tissue characterization due to ischemic heart disease and was approved by the local institutional review board. These patients were scanned using the above T2-sensitive single-shot SSFP technique. They were also scanned in the same slice position using a conventional T2-sensitive triple-inversion prepared TSE sequence (STIR) for comparison.

A child with chromosome 22q11.2 deletion syndrome and a bilobed gallbladder

We present an 11-year-old girl with a chromosome 22q11.2 microdeletion, velocardiofacial syndrome (VCFS), and a bilobed gallbladder as an incidental finding on abdominal sonography. The finding was confirmed by magnetic resonance cholangiopancreatography (MRCP).This is the first report of a gallbladder anomaly associated with a chromosome 22q11.2 deletion and the second report of a biliary tract anomaly associated with a mutation in the chromosome 22q11 region. We suggest that close attention be paid to the anatomy of the biliary tree in patients with mutations in the chromosome 22q11 region. Further study is warranted to determine the range and prevalence of biliary tract anomalies in this population.