Magnetic resonance imaging of congenital heart disease: evaluation of morphology and function

Evaluation and classification of right ventricular wall motion abnormalities in healthy subjects by 3-tesla cardiovascular magnetic resonance imaging

BACKGROUND

Right ventricular (RV) shape and function serves as an indicator in several types of heart disease such as arrhythmogenic right ventricular dysplasia (ARVD). However, there is no in-depth knowledge of RV motion, even in healthy subjects. The aim of our study was to provide a quantitative analysis of normal variations in RV wall motion in healthy subjects by cardiac magnetic resonance imaging (CMRI).

MATERIAL AND METHODS

The study population consisted of 65 consecutive patients referred for the evaluation of cardiac function by 3 Tesla CMR. Balanced steady-state free-precession images were obtained and areas of disordered RV wall motion were evaluated and classified based on a standardised segmental model for the right ventricle.

RESULTS

In 59 patients (90.8 %) wall motion abnormalities (WMA) of the right ventricle were evident. WMA were predominately detected in the apicolateral segments (72 %) compared with mediolateral (24 %, P < 0.001) and inferolateral segments (4 %, P < 0.001). Dyskinesia was the most frequent wall motion disorder (62.4 %), followed by hypokinesia (20.8 %) and bulging (16.8 %). The mean WMA diameter in the transverse plane (6.4 ± 1.9 mm) was significantly shorter compared with the diameter in the horizontal long-axis (8.1 ± 3.6 mm, P = 0.002) and short-axis plane (10.7 ± 4.6 mm).

CONCLUSION

WMA of the right ventricle are common. Therefore, one should be aware that these nonpathological wall motion disorders can easily be mistaken for a pathological regional wall motion contraction, particularly in ARVD where to date, clear wall motion criteria are lacking.

Congenital scoliosis: a review and update

Vertebral anomalies causing congenital scoliosis are classified on the basis of failures of formation, segmentation, or both. The natural history depends on the type of anomaly and the location of anomaly. Patient evaluation focuses on the history and physical examination, followed by appropriate imaging modalities. The hallmark of surgical treatment is early intervention before the development of large curvatures. The surgical treatment of a congenital deformity mandates the use of neurological monitoring to minimize the risk of perioperative neurological deficit. Modern surgical techniques have evolved to include the routine use of spinal instrumentation. Patients with associated chest wall deformities or large compensatory curves may be candidates for vertical expansion prosthetic titanium rib placement or growing rods insertion to maximize growth.

Right ventricle shape and contraction patterns and relation to magnetic resonance imaging findings

OBJECTIVE

To analyze and to describe the shape and contraction of the normal right ventricle (RV) as visualized by magnetic resonance imaging (MRI).

METHODS

Thirty normal volunteers were imaged using cine MRI in axial, short-axis, and long-axis planes. The shape and contraction of the RV were qualitatively evaluated. Quantitative evaluation of RV shape was performed by calculating the angle subtended between the planes of horizontal long-axis view (HLA) and axial view and the RV base-to-apex distance. Multiplanar reformation was used to visualize changes between corresponding views.

RESULTS

The spectrum of major RV shape (wedge, box, and round) was more variable on axial images (17%, 43%, and 23%, respectively) than on HLA images (63%, 20%, and 0%, respectively). Focal outpouching of the RV free wall was more frequent on the axial view than on the HLA view. The subtended plane angle and base-to-apex distance showed statistically significant dependence indicative of an artificially foreshortened RV in the axial view with a direct influence on RV variations.

CONCLUSIONS

With increasing subtended angles, variation of the normal RV appearance is substantially higher on axial views compared with HLA views.

Iatrogenic hyperthermia during cardiac magnetic resonance imaging

We report the occurrence of accidental hyperthermia in a young child undergoing anesthesia for cardiac magnetic resonance imaging. Although the tendency during anesthesia is to develop hypothermia, the absorbed radiofrequency energy from magnetic resonance scanning is added to metabolic energy and must be balanced by appropriate heat loss to maintain normothermia. In addition to stressing the clinical importance of temperature monitoring, this report suggests that the recommended specific absorption rates to prevent excessive patient heating may need to be revised for infants and young children.