[Magnetic resonance tomography in diagnosis and therapy follow-up of patients with congenital hip dysplasia and hip dislocation]. / Die Magnetresonanztomographie in der Diagnostik und Threrapiekontrolle von Patienten mit kongenitaler Hüftdysplasie und-luxation.

AIM: In patients with congenital dislocation of the hip the assessment of the correct position of the hip joint after closed or open reduction is very difficult to make from the radiograph with the hips in plaster. As the delayed recognition of a recurrent hip dislocation has bad effects on the outcome of the affected hip a safe and reliable imaging method must be employed. METHOD: From 1993 to 1996 6 patients with 8 congenital dislocations of the hip joint were examined by magnetic resonance imaging for evaluation of the position of the hip in plaster after reduction. Magnetic resonance imaging was performed immediately after closed or open reduction. 3 hips had to be treated by open surgery. RESULTS: The investigation confirmed that magnetic resonance imaging allows perfect differentiation between the bony and cartilaginous parts of the hip joint in plaster as well. Interpositioning of soft tissues which prevent reduction could also be visualized clearly. The best sequence in order to differentiate bony from cartilaginous structures was a gradient echo sequence in flash-technique using a flip-angle of 60 degrees. In all cases the correct position of the hip joint after reduction could be demonstrated in plaster. CONCLUSION: Therefore, magnetic resonance imaging is the imaging method of choice for confirmation and documentation of the reduced position of the hip joint in plaster. Radiographs are no longer needed.

Magnetic resonance imaging and signal-averaged electrocardiography in patients with repetitive monomorphic ventricular tachycardia and otherwise normal electrocardiogram.

Early or localized forms of arrhythmogenic right ventricular dysplasia (ARVD) have been proposed as the arrhythmogenic substrate of repetitive monomorphic ventricular tachycardia (RMVT) originating in the right ventricular outflow tract in patients without any underlying cardiac abnormality on clinical examination and echocardiography. To further examine this hypothesis, magnetic resonance imaging (MRI) and signal-averaged electrocardiography (SAECG) were performed on 23 patients with RMVT and normal 12-lead standard ECG of conducted sinus beats. MRI was performed using ECG-gated turbo spin-echo images of the heart in order to detect signs of early or localized forms of ARVD, such as localized wall thickness reductions, signal intensity increase indicating adipose tissue infiltrates, and regional bulgings or aneurysms. MRI was normal in 22 (96%) of 23 study patients. In the remaining patient (4%), MRI demonstrated signal intensity increase in the intraventricular septum but not in the right ventricular outflow tract. Time-domain analysis of the SAECG was normal in 21 (91%) of 23 patients and revealed ventricular late potentials in 2 study patients (9%). Frequency-domain analysis of the SAECG was normal in 22 (96%) of 23 patients and revealed ventricular late potentials in one study patient (4%). We conclude that normal MRI findings of the heart and absence of ventricular late potentials in the SAECG in most patients with RMVT and otherwise normal ECG do not support the hypothesis that early or localized forms of ARVD create the arrhythmogenic substrate in the majority of these patients.