[Minimally invasive pulmonary valve replacement in pediatric patients: importance of imaging]. / Minimal-invasiver Pulmonalklappenersatz bei pädiatrischen Patienten: Stellenwert der Bildgebung.

CLINICAL/METHODICAL ISSUE: Right ventricular outflow tract (RVOT) dysfunction with pulmonary regurgitation or obstruction is a common postsurgical consequence in congenital heart disease. STANDARD RADIOLOGICAL METHODS: Magnetic resonance imaging (MRI) is widely accepted as standard method of imaging in congenital heart disease. It provides anatomical and functional information without radiation exposure and is therefore well suited for serial examinations. METHODICAL INNOVATIONS: Percutaneous pulmonary valve implantation (PPVI) has been shown to be a safe and effective treatment option for patients with pulmonary valve insufficiency or stenosis. Correct patient selection for PPVI is crucial. It is important to be familiar with the indications and anatomical requirements for stent placement and to tailor imaging protocols. PERFORMANCE: Imaging the RVOT, assessment of right ventricular volumes and function and calculation of pulmonary flow and regurgitation are core elements of the MRI examination prior to PPVI. Low interobserver and intraobserver variation allows even small changes to be detected. ACHIEVEMENTS: Imaging provides relevant information for correct patient selection for PPVI and is part of postinterventional follow-up. Imaging is an important tool for documentation of success and for detection of complications. PRACTICAL RECOMMENDATIONS: Several imaging modalities are used for evaluation of RVOTs; however, MRI can provide answers to most questions without radiation exposure.

[MRI in cardiac sarcoidosis and amyloidosis]. / MRT bei kardialer Sarkoidose und Amyloidose.

CLINICAL/METHODICAL ISSUE: Sarcoidosis and amyloidosis are both multisystem disorders, which may involve the heart; however, isolated cardiac disease is rare. Diagnosis of cardiac sarcoidosis and amyloidosis is crucial because the patient prognosis is dependent on cardiac involvement and early treatment. STANDARD RADIOLOGICAL METHODS: Echocardiography is the first line imaging modality in the diagnostic work-up of both diseases, possibly giving hints towards the correct diagnosis. Besides myocardial biopsy and radionuclide studies cardiac magnetic resonance imaging (MRI) is routinely performed in patients suspect of having infiltrative cardiomyopathy. METHODICAL INNOVATIONS: The T1 mapping procedure is currently being evaluated as a new technique for detection and quantification of global myocardial enhancement, as seen in cardiac amyloidosis. PERFORMANCE: Sensitivities and specificities for detection of cardiac sarcoidosis and amyloidosis can be significantly improved by MRI, especially with late gadolinium enhancement (LGE) imaging. In cardiac sarcoidosis the use of LGE is outcome-related while in amyloidosis analysis of T1-mapping may be of prognostic value. PRACTICAL RECOMMENDATIONS: If cardiac involvement in sarcoidosis or amyloidosis is suspected cardiac MRI including LGE should be performed for establishing the diagnosis.

MR first pass perfusion of benign and malignant cardiac tumours-significant differences and diagnostic accuracy.

OBJECTIVES: To determine the diagnostic value of magnetic resonance (MR) first pass perfusion in the differentiation of benign and malignant cardiac tumours. METHODS: 24 patients with cardiac tumours (11 malignant, histopathological correlation present in all cases) were examined using MRI. In addition to morphological sequences a saturation-recovery T1w-GRE technique was implemented for tumour perfusion. The maximum relative signal enhancement (RSE[%]) and the slope of the RSE(t)-curve (slopeRSE[%/s]) of tumour tissue were assessed. A t-test was used to identify significant differences between benign and malignant tumours. Sensitivities and specificities were calculated for detection of malignant lesions and were compared with the sensitivity and specificity based on solely morphological image assessment. RESULTS: The RSE and slopeRSE of malignant cardiac tumours were significantly higher compared with benign lesions (p < 0.001 and p < 0.001). The calculated sensitivities and specificities of RSE and slopeRSE for identification of malignant lesions were 100% and 84.6% and 100% and 92.3%, respectively with cut-off values of 80% and 6%/s. The sensitivity and specificity for identification of malignant lesions on the basis of morphological imaging alone were 90.9% and 69.2%. CONCLUSIONS: With first pass perfusion, malignant cardiac masses can be identified with higher sensitivity and specificity compared with morphological image assessment alone.

Contrast enhanced IR-SSFP examination compared with T1-weighted turbo spin-echo imaging of cardiac tumors and tumorlike lesions.

PURPOSE: To show that the use of an early and delayed contrast enhanced multislice inversion recovery steady state free precession (SS-IR-SSFP) is a valuable substitute for conventional post-contrast fat saturated turbo spin-echo (TSE) T1-weighted images in the assessment of cardiac tumors. MATERIALS AND METHODS: 34 consecutive patients referred for MRI in order to assess cardiac tumors were examined. Shortly after administration of gadopenetate dimeglumine (Gd-DTPA) images were obtained using a SS-IR-SSFP sequence. The inversion time (TI) was set at 350ms to achieve a good demarcation of intracavitary tumor spread. Hereafter 9 slices of a T1w TSE sequence were obtained. Finally a SS-IR-SSFP sequence with an optimized TI to null normal myocardium was employed. Quantitative comparisons were performed by calculating contrast to noise ratios of tumor/myocardium (CNR(tumor/myo)) and CNR of tumor/left ventricular cavity (CNR(tumor/LVC)). Image quality was assessed regarding overall image quality, artifacts and tumor conspicuity. RESULTS: Neither calculation of CNR(tumor/LVC) when comparing the early IR-SSFP and T1w TSE, nor calculation of CNR(tumor/myo) when comparing the late IR-SSFP and T1w TSE sequence resulted in statistically significant differences. However, qualitative assessments revealed significant superior results for the early and the late IR-SSFP images compared to the T1-weighted TSE images (p<0.001). CONCLUSIONS: Image quality and tumor conspicuity were superior and image degradation by artifacts was less on IR-SSFP images compared to TSE images without loss of CNR. Thus the use of IR-SSFP sequences is an attractive alternative imaging method compared to post-contrast T1w TSE imaging in the assessment of cardiac tumors.

[Cardiac functional analysis with MRI]. / Kardiale Funktionsanalyse mittels MRT.

Cardiovascular diseases (CVD) are among the leading causes of death worldwide. Even in the 21(st) century CVD will still be the most frequent cause of morbidity and mortality. Precise evaluation of cardiac function is therefore mandatory for therapy planning and monitoring. In this article the contribution of MRI-based analysis of cardiac function will be addressed. Nowadays cine-MRI is considered as the standard of reference (SOR) in cardiac functional analysis. ECG-triggered steady-state free precession (SSFP) sequences are mainly used as they stand out due to short acquisition times and excellent contrast between the myocardium and the ventricular cavity. An indispensible requirement for cardiac functional analysis is an exact planning of the examination and based on that the coverage of the whole ventricle in short axial slices. By means of dedicated post-processing software, manual or semi-automatic segmentation of the endocardial and epicardial contours is necessary for functional analysis. In this way end-diastolic volume (EDV), end-systolic volume (ESV) and the ejection fraction (EF) are defined and regional wall motion abnormalities (RWMA) can be detected.

[Late gadolinium enhancement in the diagnostics of ischemic heart disease: technical principles, contrast optimization and clinical application]. / Late-Gadolinium-Enhancement in der Diagnostik der koronaren Herzerkrankung : Technische Grundlagen, Kontrastoptimierung und klinische Anwendung.

BACKGROUND: The purpose of the study was to explore a "dark blood" technique and to compare it with a standard inversion recovery gradient echo (IR GRE) sequence in the visualization of myocardial infarction. PATIENTS AND METHODS: A total of 9 patients were examined with standard IR GRE and a "dark blood" sequence 15 mins after contrast medium application (0.2 mmol/kg body weight gadobenate dimeglumine). Contrast-to-noise ratios (CNR) were calculated for each sequence. RESULTS: The CNR(inf-lvc) was significantly higher in the "dark blood" technique compared to the IR GRE sequence, while the CNR(inf-myo) was significantly lower. CONCLUSIONS: Small subendocardial infarctions may be easier to detect with the "dark blood" technique. However, the standard IR GRE sequence is superior in the demarcation of infarctions in relation to the myocardium and cannot be replaced by the "dark blood" technique.

[Evaluation of diastolic function in patients with constrictive pericarditis before and after pericardectomy]. / Vergleich prä- und postoperativer MRT-Untersuchungen des Herzens bei Patienten mit Pericarditis constrictiva unter besonderer Berücksichtigung der diastolischen Funktion.

PURPOSE: The aim of the study was to evaluate diastolic function in patients with constrictive pericarditis using velocity-encoded flow measurements before and after pericardectomy. MATERIALS AND METHODS: Velocity-encoded flow measurements were performed at the atrioventricular valves in nine patients with constrictive pericarditis. The resulting flow curves were evaluated. For assessment of diastolic function the amplitudes of the E and A waves were measured and the E to A wave ratios calculated. Appearance of mid-diastolic flow, indicating diastolic dysfunction, was registered. RESULTS: The measurements at the mitral valves prior to pericardectomy revealed diastolic dysfunction grade I in two patients, grade II in three patients, and grade III in three patients. Mid-diastolic flow was detected in two patients. At the tricuspid valves diastolic dysfunction grade I was present in two patients, grade II in four patients, and grade III in three patients. Improvement of diastolic function after pericardectomy was documented in five patients at the mitral valve and in two patients at the tricuspid valve. CONCLUSION: Velocity-encoded flow measurements are feasible and a valuable tool for assessment of diastolic function in patients with constrictive pericarditis prior to and after pericardectomy.

[Magnetic resonance imaging for the assessment of myocardial perfusion: value of various semiquantitative perfusion parameters]. / MRT zur Beurteilung der Myokardperfusion: Aussagekraft verschiedener semiquantitativer Perfusionsparameter.

PURPOSE: The aim of this study was to determine the diagnostic accuracy of various semiquantitative perfusion parameters of the magnetic resonance perfusion examination of the myocardium compared to conventional coronary angiography. PATIENTS, MATERIAL AND METHODS: Twenty patients with suspicion of coronary artery disease who underwent coronary angiography were examined by MR imaging within 14 days before or after coronary angiography. A perfusion examination during adenosine application (140 microg/kg/min) and at rest was performed using a saturation recovery turboFLASH sequence. The semi-quantitative parameters maximum signal intensity (SIM), time-to-peak (TTP), area under the curve (AUC) and upslope (US) were determined using dedicated software (Dynamic Signal Analysis, ARGUS, Siemens Medical Solutions) for the evaluation of the signal-intensity-time curves. In addition, the ratio of these parameters (MPRI: myocardial perfusion reserve index) were determined by dividing the values of the stress examination by the values of the rest examination. RESULTS: Accuracy was 78.4% (SIM), 64.9% (TTP), 64.2% (AUC) and 70.4% (US) for the evaluation of the stress examination. Accuracy for the MPRI of the semi-quantitative parameters was 72.2% (SIM), 50.9% (TTP), 72.2% (AUC) und 89.1% (US). CONCLUSION: A combined semi-quantitative evaluation of the MPRI values using the ratio of the upslope values of the stress and rest examination was shown to be the most accurate method. MPRI (US(Stress)/US(Rest)) is superior to an evaluation of the stress examination alone.