Biomedical subjects
Publications and source records attributed to Hans Meyer.
Cardiotoxicity is a well-known consequence of anthracycline chemotherapy. We report CMR findings not previously described in two patients with anthracycline cardiotoxicity following treatment for Ewing's sarcoma. Subendocardial enhancement on late gadolinium contrast-enhanced CMR was present in both cases, with histological correlation in one case.
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PURPOSE: To evaluate the feasibility of rapid free-breathing phase-contrast MRI (PC-MRI) at different in-plane resolutions combined with sensitivity encoding (SENSE) for flow quantification in the great arteries in healthy adult volunteers. METHODS: In 13 volunteers (mean age 33.0 +/- 7.4 years), blood flow rates in the pulmonary artery (Qp), ascending aorta (Qs), and flow ratio Qp/Qs were determined by PC-MRI with SENSE reduction-factor 2 and 3 (SF-2, SF-3). Additionally, we used PC-MRI with higher spatial in-plane resolution (1.6 x 2.1 mm vs. 2.3 x 3.1 mm) with/without SF-3. Standard (= reference) PC-MRI, which used two excitations (NEX=2), was compared with PC-MRI sequences with NEX=1. RESULTS: Reduction of signal averages and application of SENSE accelerated flow measurements by a factor of 3.8 (5.5) using PC-MRI with SF-2 (SF-3): Scan time was 36 sec (SF-2) and 25 sec (SF-3) at average heart rate of 69/min. The mean Qp/Qs by reference PC-MRI was 1.03 +/- 0.07 (range, 0.89-1.16), and 1.0 +/- 0.11 (range, 0.86-1.24) by PC-MRI + SF-3, respectively. For blood flow rate through the pulmonary artery and aorta, and for Qp/Qs ratio, we found differences of -3% to +4%. The lower limits of agreement (mean - 2 SD) ranged between -14% and -21%, and upper limits (mean + 2 SD) between +9% and +30%, demonstrating clinically acceptable agreement with standard PC-MRI (Bland-Altman analysis). PC-MRI at higher in-plane resolution both with/without SENSE yielded slightly smaller aortic and pulmonary flows (mean differences 5% to 7%, p < 0.05). CONCLUSIONS. In adults, PC-MRI may be safely combined with SENSE to reduce scan time for a quantitative flow measurement in the great arteries to "30 seconds. High in-plane resolution was not advantageous.
BACKGROUND: Sinus node dysfunction is a frequent complication of Fontan-type procedure. Epicardial pacing is considered as the standard treatment for these patients. METHODS AND RESULTS: We evaluated an endocardial approach in seven patients using a 4.1 French bipolar lumenless lead (SelectSecure) that is positioned through a steerable guiding catheter. Either a purely transvenous or an open transatrial approach can be used for lead placement. The smallest child weighed 12 kg. Individual anatomy was assessed preimplantation using magnetic resonance imaging and injection of radiographic contrast agent through the guiding catheter. A pullback pressure recording was used to confirm unimpaired blood flow into the pulmonary artery. Five of our seven patients underwent de novo transvenous atrial lead implantation for AAIR pacing. In the remaining two patients, both atrial and ventricular leads were inserted. One patient with an intraatrial tunnel underwent transvenous-lead placement. The remaining patient with an extracardiac conduit received atrial and ventricular leads implanted through a guiding catheter inserted through an atriotomy. The postoperative management included short- or long-term oral anticoagulation. CONCLUSIONS: Transvenous endocardial lead implantation avoids the problem of increasing capture thresholds typically observed with epicardial leads. Due to its high tensile strength and lumenless design, the isodiametric lead is expected to remain extractable for an extended period of time.
OBJECTIVE: We retrospectively reviewed 104 consecutive patients who underwent orthotopic heart transplantation between November 1989 and February 2004. PATIENTS AND METHODS: From November 1989 to February 2004, the total number of heart transplantations were 1,340 cases at our institute. One hundred four (7.8%) of these 1,340 patients were pediatrics. Average age was 6.2 years, ranging from 4 months to 16 years. The cause of heart disease before transplantation was: idiopathic dilated cardiomyopathy (DCM) in 74 patients (71%), and congenital heart disease (CHD) in 30 (29%). RESULTS: Hospital mortality rate was 14.4% (15 patients). Late complications were rejection in 23 (22.1%), infection in 11 (10.6%), gingival hyperplasia in 28 (26.9%), hypertention in 22 (21.1%), coronary artery disease (CAD) in 12 (12.5%), graft failure in 11(10.5%), and malignancy in 2 (1.9%). Late mortality occurred in 11 (10.6%) patients. Causes of death were sudden death in 2 (1.9%), CAD in 3 (2.8%), graft failure in 1 (1.0%), acute rejection in 4 (4.6%), and infection in 1 (1.0%). Actuarial survival rates in pediatrics at 1, 5, 10 years were 82%, 80%, and 78%, respectively. On the other hand, actuarial survival rates in adults at 1, 5, 10 years were 78%, 75%, 59%, respectively. CONCLUSION: Heart transplantation for pediatrics is an effective therapy with acceptable morbidity and mortality. The long-term survival results in pediatrics are comparable to those of adult heart transplantations. However, the actuarial survival rate in pediatrics after 10 years is significantly better than in adults' cases. Renal function in pediatric heart transplantation recipients treated with cyclosporine remains stable during long-term follow-up.
BACKGROUND: Operator-independent isotropic 3D MRI may greatly simplify the assessment of complex morphology in congenital heart disease. We sought to evaluate the reliability of this new approach. METHODS AND RESULTS: In 31 adolescent and adult patients (age, 6 to 42 years; median, 16 years) with congenital heart disease, cardiac morphology was determined with free-breathing (navigator-gated), isotropic, 3D steady-state free-precession (3D SSFP) MRI and independently evaluated by 2 observers. Cardiac diagnoses and multiple distance measurements were compared with conventional MR reference sequences (ie, spin-echo, cine gradient-echo, contrast-enhanced MR angiography) and with echocardiography/cine cardioangiography or surgery. Of the 31 patients, 24 had native congenital heart defects or residual defects after repair that warranted immediate treatment. None of these defects was missed by 3D SSFP. Novel diagnostic issues were discovered in 4 of 31 patients (coronary anomalies, n=3; left juxtaposition of the right atrial appendage in double-outlet right ventricle and transposition of the great arteries, 1). For sizes of valves and vessels, we found minor mean differences of -1.1 to 1.6 mm, with SD ranging from 1.2 to 2.9 mm, demonstrating overall good agreement with standard MRI (Bland-Altman analysis). Interobserver variability of 3D SSFP distance measures was low; mean differences ranged from -1.5 to 1.0 mm, and SD ranged from 0.8 to 2.5 mm. Scatter was lower for extracardiac than intracardiac measures. CONCLUSIONS: In adolescents and adults, isotropic 3D SSFP MRI allows reliable assessment of complex cardiac morphology. Distance measurements are accurate and reproducible. Thus, a single operator-independent acquisition may substitute for conventional 2D MRI sequences to accelerate and simplify MR scanning in congenital heart disease.
BACKGROUND: Flow quantification in real time by phase-contrast MRI (PC-MRI) may provide unique hemodynamic information in congenital heart disease, but available techniques have important limitations. We sought to validate a novel real-time magnetic resonance flow sequence in children. METHODS AND RESULTS: In 14 pediatric patients (mean age 5.2+/-2.0 years) with cardiac left-to-right shunt, pulmonary (Q(p)) and aortic (Q(s)) flow rates were determined by nontriggered free-breathing real-time PC-MRI with single-shot echo-planar imaging combined with sensitivity encoding, which yielded 25 phase images per second at 2.7x2.7-mm in-plane resolution (field of view 30x34 cm2). Over a 9.5-second period that included 2 to 5 respiratory cycles, 16.6+/-2.6 subsequent stroke volumes (range 13 to 22) were acquired in each vessel. Results were compared with conventional retrospectively ECG-gated PC-MRI. Mean Q(p)/Q(s) by conventional PC-MRI was 1.91+/-0.64, and it was 1.94+/-0.68 (mean+/-SD) by real-time PC-MRI. For blood flow rate through pulmonary artery and aorta, we found differences of 2% to 3% (Bland-Altman analysis), with lower limits of agreement of -11% to -13% (mean-2 SD) and upper limits of 18% to 19% (mean+2 SD), which demonstrated good agreement between both methods. Mean difference for Q(p)/Q(s) was 1%, with limits of agreement ranging between -18% and 22% (mean+/-2 SD). High repeatability but some flow overestimation was observed in vitro (pulsatile flow phantom) with real-time PC-MRI, whereas conventional PC-MRI was accurate. Beat-to-beat stroke-volume variation was 6.1+/-2.3% in vivo and 3.7+/-0.3% in vitro. CONCLUSIONS: Beat-to-beat quantification of pulmonary and aortic flows and hence left-to-right shunt within a few seconds is reliable by nontriggered real-time PC-MRI with echo-planar imaging and sensitivity encoding. Good spatial/temporal resolution and a large field of view may render the sequence valuable for multiple applications in congenital heart disease.
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BACKGROUND: Parallel imaging by sensitivity encoding (SENSE) may considerably reduce scan time in MRI. For rapid flow quantification in children with congenital heart disease, we evaluated phase-contrast MRI (PC-MRI) techniques combined with SENSE. METHODS AND RESULTS: In 22 pediatric patients (mean age, 7.2+/-6.2 years) with cardiac left-to-right shunt, blood flow rate in the pulmonary artery (Qp) and ascending aorta (Qs) and flow ratio Qp/Qs were determined by PC-MRI with SENSE reduction-factor 2 and 3 (SF-2 and SF-3). Additionally, we used PC-MRI with higher spatial in-plane resolution (1.6x2.1 versus 2.3x3.1 mm) with and without SF-3. Results were compared with a recently validated standard PC-MRI protocol and tested in vitro using a pulsatile flow phantom. Reduction of signal averages from 2 to 1 and application of SENSE accelerated flow measurements by a factor of 3.5 (5.2) using PC-MRI with SF-2 (SF-3) compared with standard PC-MRI. For blood flow rate through the pulmonary artery and aorta, as well as for the Qp/Qs ratio we found negligible differences of +/-3%, lower limits of agreement (mean+/-2 SD) of -7% to -18%, and upper limits of agreement (mean+/-2 SD) of +3 to +24%, demonstrating good agreement with standard PC-MRI. Mean Qp/Qs ratio by standard PC-MRI was 1.69+/-0.45 (range, 1.27 to 2.79). Interobserver variability was low, and high accuracy was confirmed in vitro for all protocols. CONCLUSIONS: PC-MRI for flow quantitation may be combined with SENSE to achieve a substantive reduction of scanning time. In children with left-to-right shunt, Qp/Qs quantification is possible by PC-MRI+SF-3 in <60 seconds. Use of higher in-plane resolution did not improve measurement results.
PURPOSE: To evaluate phase-contrast magnetic resonance (MR) imaging for sizing of secundum atrial septal defects (ASDs) and inflow MR angiography for detection of associated venous anomalies in pediatric patients with inconclusive transthoracic echocardiographic (TTE) results. MATERIALS AND METHODS: Sixty-five children (mean age, 5.4 years +/- 2.7 [SD]) with ASD and inconclusive TTE results underwent phase-contrast MR imaging. Defect size and rim distances measured on MR imaging sections obtained in the ASD plane and from the defect to the venae cavae, aortic root, and atrioventricular valves were compared with transesophageal echocardiographic (TEE) findings (n = 30) during transcatheter closure or surgical measurements (n = 40) by using Bland-Altman analysis. Inflow MR angiography was compared with invasive cine angiocardiography for detection of associated venous anomalies. RESULTS: For ASD size, mean differences were less than 1 mm between MR imaging and TEE measurements (with upper and lower limits of agreement between 2.3 and -3.3 mm) and were between 1.2 and -1.6 mm between MR imaging and surgical measurements (with upper and lower limits of agreement between 4.7 and -5.2 mm). Septal rim measurements at MR imaging agreed fairly well with TEE and surgical results. Septal length was overestimated at MR imaging versus TEE (mean difference, 3.0 mm; upper and lower limits of agreement, between 8.0 and -2.8 mm), but MR imaging septal length measurements agreed with surgical results. Rim distance to coronary sinus was difficult to assess. MR imaging enabled referral of 25 of 30 patients for successful transcatheter closure; five patients were found to have too large defects after balloon sizing. Multiple ASDs and/or associated vascular anomalies in 17 of 65 patients were clearly identified at MR imaging, compared with results of TEE, surgery, and cardiac catheterization. CONCLUSION: In children with ASD and inconclusive TTE results, MR imaging can enable determination of defect size, rim distances to adjacent structures, and venous connections.
BACKGROUND: We reviewed our 12-year experience with staged reconstruction for hypoplasia of the left heart, examining the results of each surgical step and the impact of the year of the Norwood operation on survival. We compared survival of patients with hypoplasia of the left heart subsequent to completion of the Fontan circulation to survival of patients with a dominant left ventricle undergoing a Fontan procedure. PATIENTS: Between 1989 and 2001, we performed a first stage procedure in 89 patients. Their median age was 9 days, with a range from 2 to 140 days, and the median weight was 3.4 kg, with a range from 2.4 to 5.4 kg. RESULTS: Survival at 1, 4, and 10 years was 55%, 49%, and 49%, respectively. We experienced 23 early deaths (26%), and 12 deaths between the stages of the Norwood cascade. Of our patients, 42 underwent the second stage, and 30 the third stage. Prior to the first stage, symptoms of necrotising enterocolitis, and of obstructed pulmonary venous return, influenced survival significantly. The latter was eliminated as risk factor when surgery was performed within the first week of life. During the later part of our experience, survival at the first stage operation improved significantly, with survival at 3 years increasing from 42% to 75% for the patients at standard-risk (p = 0.017), and from 17% to 42% for those deemed to be at high-risk (p = 0.1). No deaths occurred in 23 patients older than 3 years of age, all of whom had proceeded through the third stage. After completion of the Fontan circulation, the survival of the patients with hypoplasia of the left heart at 4 years was comparable to the survival of patients undergoing the Fontan procedure with a dominant left ventricle (88% versus 90%, p = 0.8). CONCLUSIONS: Early and intermediate survival has improved significantly over the period of 12 years. Late death has been uncommon, and none of our patients are listed for cardiac transplantation.
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