Performing cardiac MR imaging: an overview

Characterization of incidental cardiac masses in oncological patients using a new CT-based tumor volume perfusion technique

Cardiac masses are challenging for non-invasive diagnostic procedures and therapy, respectively. In tumor patients differentiation between primary or secondary cardiac neoplasm and thrombus is a frequent and knowingly difficult task to manage. To avoid complex and unnecessary surgical diagnostic procedures non-invasive methods are in favor. For initiation of adequate therapy and evaluation of prognosis, however, early and reliable diagnosis is mandatory. So far, echocardiography and magnetic resonance imaging represent the mainstay for cardiac imaging diagnosis. Recently, the new technique of CT-based tumor volume perfusion (VPCT) measurement has advanced to a potent, reliable, and easy to perform alternative for cardiac imaging. The purpose of this study was to review the existing spectrum of diagnostic modalities for characterization of cardiac masses in an oncologic patient cohort with emphasis on their strengths and limitations and to present the benefit from using the novel technique called VPCT for this purpose.

Magnetic resonance imaging for simultaneous morphological and functional evaluation of esophageal motility disorders

PURPOSES

The purpose of this study was to evaluate the feasibility and safety of esophageal functional magnetic resonance imaging (fMRI) for the diagnosis of achalasia.

METHODS

Eleven patients with suspected achalasia and three normal subjects underwent fMRI while swallowing clear liquid with original sequences; "T2-weighed single-shot fast spin-echo" and "Fast Imaging Employing Steady-state Acquisition". The fMRI-based diagnosis was compared with that based on manometry. The luminal fluctuation index (LFI) and Dd/Ds ratio were used for the objective evaluation of the esophageal peristalsis and relaxation of the lower esophageal sphincter (LES).

RESULTS

Functional MRI showed a dilated tortuous esophagus with no tumor, poor clearance, simultaneous waves, aperistalsis, and impaired LES relaxation in all but one case, allowing the diagnosis of achalasia with accuracy similar to that of manometry. The LFI (median 0.08, range 0.03-0.25) and Dd/Ds ratio (1.40, 1.0-2.3) of the patient group were significantly lower than those of the normal subjects [1.50, 2.32-4.05, and 2.59 (2.32-4.05)]. No severe adverse events directly related to fMRI were noted.

CONCLUSIONS

Using our protocol, fMRI was considered to be safe and feasible for the diagnosis of achalasia. Given the widespread use of MRI, esophageal fMRI, which does not require exposure to radiation, could be a potentially useful diagnostic tool for patients with esophageal motility disorders.

An unusual cause of susceptibility artifact in magnetic resonance imaging

Magnetic susceptibility artifact has been documented with various implants and devices, which require appropriate identification with screening of patients prior to subjecting them to magnetic resonance examination. We performed cardiovascular magnetic resonance (CMR) examination of the aorta in a 24-year-old woman in the setting of repaired aortic coarctation, and found magnetic susceptibility artifact arising from the stomach in the absence of known susceptibility artifact-producing material in this region. Further history revealed that she had ingested a prenatal vitamin prior to imaging, prompting experimental analyses that led us to conclude that iron-containing vitamins may be a source of magnetic susceptibility artifact.

ACR Practice Guideline for the Performance and Interpretation of Cardiac Magnetic Resonance Imaging (MRI)

Magnetic resonance imaging (MRI) is an established imaging modality, recognized for its value in the assessment and monitoring of a wide range of cardiac pathology. It can provide physiologic as well as anatomic information. Image interpretation requires both well-developed MRI skills and knowledge of cardiac pathology. Radiologists, because of their extensive experience in MRI, have an important role in its application in the heart. The guidelines presented here are an educational tool designed to assist practitioners in providing the best possible patient care via the diagnostic methods of cardiac MRI. American College of Radiology requirements for physicians and personnel performing and interpreting cardiac MRI, which will become applicable by July 1, 2008, are also presented.