Reproducibility of manual and semi-automated late enhancement quantification in patients with Fabry disease.

BACKGROUND: Late enhancement (LE) imaging is increasingly used for diagnosis of non-ischemic cardiomyopathy. However, the mostly patchy appearance of LE in this context may reduce the reproducibility of LE measurement. PURPOSE: To report intra- and inter-observer variabilities of LE measurements in Fabry disease using manual and semi-automated quantification. MATERIAL AND METHODS: Twenty MRI data-sets of male patients aged 44 ± 7 years were analyzed twice (interval 12 months) by one observer and additionally once by a second observer. Left ventricular (LV) parameters were determined using cine MRI. Gradient-echo LE images were analyzed by manual planimetry and by a semi-automatic prototype software. Variabilities were determined by Bland-Altman analyses and additionally intra-class correlation coefficient (ICC) values were calculated to survey intra- and inter-observer reproducibility. RESULTS: The amount of LE was 5.2 ± 5.1 mL or 2.8 ± 2.6 % of LV mass (observer 2). LE was detected predominantly intramurally in a patchy pattern. All patients had LE restricted to the basal infero-lateral parts of the LV. The extent of LE correlated to LV mass (207 ± 70 g, P < 0.05, r = 0.6). The intra- and inter-observer variabilities were -0.6 to 1.0 mL and -0.7 to 1.6 mL, respectively (95% confidence intervals). ICC values were 0.981-0.999. The semi-automatic software allowed quantification of LE areas in all patients. The comparison of LE amount determined by semi-automatic software versus manual planimetry yielded an intra-observer variability ranging from -1.9 to 2.3 mL. CONCLUSION: Semi-automatic planimetry of patchy LE in patients with Fabry disease is feasible. The determined intra- and inter-observer variabilities for manual and semi-automatic planimetry were in the range of 20-40% of LE amount with high ICC values.

Two-dimensional speckle tracking as a non-invasive tool for identification of myocardial fibrosis in Fabry disease.

AIMS: This cross-sectional study aimed to analyse myocardial deformation in patients with Fabry disease (FD) in order to evaluate speckle tracking as a method for non-invasive determination of myocardial fibrosis. Myocardial fibrosis is common in Fabry cardiomyopathy and is associated with disease progression and severe prognosis. METHODS AND RESULTS: In 101 consecutive Fabry patients (39.8 ± 12.9 years; 42 males), the quantitative measurement of myocardial fibrosis with magnetic resonance imaging was compared with regional myocardial deformation assessed by speckle-tracking imaging. Patients were analysed in relation to per cent of late-enhancement (LE)-positive areas of left-ventricular (LV) mass. Fifty-two patients (51%) displayed LE with a mean volume of 1.2 ± 1.8% of total LV mass. Predominantly basal lateral and posterior segments were affected. Patients with LE had lower global systolic longitudinal strain than those without (LE -14.8 ± 3.5% and -18.9 ± 2.1%, respectively; P < 0.001). Loss of global deformation, quantified by speckle tracking, was predominantly caused by basal posterior (P = 0.049) and lateral (P = 0.005) segments and global systolic strain correlated with the amount of LE (r = 0.543; P < 0.001). Patients with severe LE (>2%, n = 22) showed the lowest deformation values (-5.9 ± 8.4%) in basal postero-lateral segments when compared with those with mild (<2%; n = 30, -7.1 ± 7.5%) or no LE (n = 49, -16.3 ± 3.3%). These changes were accompanied by thinning of the posterior wall and a decrease in diastolic function, whereas ejection fraction and LV end-diastolic diameter were not different. Receiver operating characteristic analysis revealed that the systolic strain of basal postero-lateral segments was the most powerful predictor to distinguish between patients with and without LE (sensitivity = 90%; specificity = 97%, area under the curve = 0.913; P < 0.001). CONCLUSIONS: Late enhancement is associated with lower longitudinal strain in the fibrotic wall segments. Speckle tracking can be used as a tool for the indirect evaluation of LE in FD.

Cross-sectional baseline analysis of electrocardiography in a large cohort of patients with untreated Fabry disease.

BACKGROUND: Morphology and function of Fabry cardiomyopathy has been previously studied by echocardiography and cardiac magnetic resonance (CMR). However, the value of electrocardiography (ECG) in relation to these two techniques remains largely unknown. METHODS: One hundred fifty genetically confirmed Fabry patients were investigated using a comprehensive clinical workup comprising 12-lead ECG, echocardiography, and CMR. RESULTS: ECG parameters at rest [PR, P wave, QT, QTc, QT dispersion and time interval from the peak to the end of the T wave (Tpeak to Tend)] were normal in the entire cohort and did not distinguish between males and females or stages of cardiomyopathy. A significant positive correlation was found between left ventricular (LV) mass on CMR and both the QRS duration and the LV Sokolow index, with the highest values in male patients with an advanced cardiomyopathy stage. No prediction of late enhancement on CMR (a sign for replacement fibrosis) was possible by a single ECG parameter. However, the absence of ST or T alterations (in 37 of 38 patients) specifically excluded late enhancement on CMR. CONCLUSION: Our data in a large cohort of Fabry patients, including all cardiomyopathy stages, show, in contrast to former assumptions, that ECG parameters are not suitable to stage Fabry cardiomoypathy. Most ECG parameters were normal in the complete cohort. However, the absence of ST or T alterations seems to almost exclude late enhancement on CMR in these patients.

Small-bowel MRI in children and young adults with Crohn disease: retrospective head-to-head comparison of contrast-enhanced and diffusion-weighted MRI.

BACKGROUND: Small-bowel MRI based on contrast-enhanced T1-weighted sequences has been challenged by diffusion-weighted imaging (DWI) for detection of inflammatory bowel lesions and complications in patients with Crohn disease. OBJECTIVE: To evaluate free-breathing DWI, as compared to contrast-enhanced MRI, in children, adolescents and young adults with Crohn disease. MATERIALS AND METHODS: This retrospective study included 33 children and young adults with Crohn disease ages 17 ± 3 years (mean ± standard deviation) and 27 matched controls who underwent small-bowel MRI with contrast-enhanced T1-weighted sequences and DWI at 1.5 T. The detectability of Crohn manifestations was determined. Concurrent colonoscopy as reference was available in two-thirds of the children with Crohn disease. RESULTS: DWI and contrast-enhanced MRI correctly identified 32 and 31 patients, respectively. All 22 small-bowel lesions and all Crohn complications were detected. False-positive findings (two on DWI, one on contrast-enhanced MRI), compared to colonoscopy, were a result of large-bowel lumen collapse. Inflammatory wall thickening was comparable on DWI and contrast-enhanced MRI. DWI was superior to contrast-enhanced MRI for detection of lesions in 27% of the assessed bowel segments and equal to contrast-enhanced MRI in 71% of segments. CONCLUSION: DWI facilitates fast, accurate and comprehensive workup in Crohn disease without the need for intravenous administration of contrast medium. Contrast-enhanced MRI is superior in terms of spatial resolution and multiplanar acquisition.

Spongious hypertrophic cardiomyopathy in patients with mutations in the four-and-a-half LIM domain 1 gene.

BACKGROUND: X-linked myopathy with postural muscle atrophy is a novel X-linked myopathy caused by mutations in the four-and-a-half LIM domain 1 gene (FHL1). Cardiac involvement was suspected in initial publications. We now systematically analyzed the association of the FHL1 genotype with the cardiac phenotype to establish a potential cardiac involvement in the disease. METHODS AND RESULTS: Seventeen male patients and 23 female mutation carriers were compared with healthy controls. Every patient underwent a comprehensive clinical and cardiovascular workup. ECG abnormalities occurred frequently in affected males and were less frequent in heterozygous females. Both male and female mutation carriers had increased myocardial mass (affected males=115.1±25.3 g/m(2); heterozygous females=95.1±19.6 g/m(2); controls=89.0±15.6 g/m(2) and 72.6±12.6 g/m(2); respectively) with increased wall thickness (typically midventricular and apical segments) mainly in affected males. Longitudinal systolic function was reduced in affected males (radial systolic strain: affected males=24.6±11.8%; male controls=43.2±14.8%; P=0.002). Diastolic dysfunction occurred in both affected males and heterozygous females. Cardiac MRI revealed a morphological hallmark of X-linked myopathy with postural muscle atrophy; a characteristic spongious structure and replacement fibrosis indicated by late enhancement could be detected in most affected males. X-linked myopathy with postural muscle atrophy was associated with reduced exercise capacity in affected males but not in heterozygous female mutation carriers. CONCLUSIONS: X-linked myopathy with postural muscle atrophy patients consistently showed electrical, functional, and characteristic morphological cardiac abnormalities that translate into reduced exercise capacity. Reduced systolic and diastolic function is associated with a novel type of spongious hypertrophic cardiomyopathy. An unexpected finding was that some cardiac abnormalities were also present in heterozygous female mutation carriers.

MR-based analysis of regional cardiac function in relation to cellular integrity in Fabry disease.

BACKGROUND: Fabry cardiomyopathy is characterized by left ventricular (LV) hypertrophy and regional fibrosis. Recent high-end echocardiography studies of selected LV sections suggest an interrelation between regional fibrosis, impaired function, and hypertrophy possibly changing under specific enzyme replacement therapy (ERT). METHODS: Magnetic resonance imaging (MRI) was used for a region dependent study of cardiac function, morphology and late enhancement (LE) in 25 Fabry patients before and after 12 months of ERT in comparison to 43 healthy volunteers. RESULTS: Fabry patients presented with LV increased wall thickness (EDWT) and reduced wall thickening (WT) with a focus on basal and midventricular regions corresponding to areas of LE. The degree of hypertrophy and hypokinesia were the highest if LE was detectable. A significant decrease of the EDWT under ERT was observed in LE negative patients accompanied by a decline of hypokinesia with regional differences. CONCLUSIONS: Regional differences of LV hypertrophy and wall motion were detected corresponding to the distribution of myocardial fibrosis (LE). Functional impairment was closely restricted to fibrotic regions while morphologic changes slightly exceeded the areas of fibrosis. ERT resulted in regional improvements whereby absence of fibrosis was connected to a better outcome.

Novel desmoplakin mutation: juvenile biventricular cardiomyopathy with left ventricular non-compaction and acantholytic palmoplantar keratoderma.

Two sons of a consanguineous marriage developed biventricular cardiomyopathy. One boy died of severe heart failure at the age of 6 years, the other was transplanted because of severe heart failure at the age of 10 years. In addition, focal palmoplantar keratoderma and woolly hair were apparent in both boys. As similar phenotypes have been described in Naxos disease and Carvajal syndrome, respectively, the genes for plakoglobin (JUP) and desmoplakin (DSP) were screened for mutations using direct genomic sequencing. A novel homozygous 2 bp deletion was identified in an alternatively spliced region of DSP. The deletion 5208_5209delAG led to a frameshift downstream of amino acid 1,736 with a premature truncation of the predominant cardiac isoform DSP-1. This novel homozygous truncating mutation in the isoform-1 specific region of the DSP C-terminus caused Carvajal syndrome comprising severe early-onset heart failure with features of non-compaction cardiomyopathy, woolly hair and an acantholytic form of palmoplantar keratoderma in our patient. Congenital hair abnormality and manifestation of the cutaneous phenotype in toddler age can help to identify children at risk for cardiac death.

Differences in Fabry cardiomyopathy between female and male patients: consequences for diagnostic assessment.

OBJECTIVES: We hypothesized that Fabry cardiomyopathy in female patients might differ substantially from that in male patients and sought to prove this hypothesis in a large cohort consisting of 104 patients with Fabry disease. BACKGROUND: Fabry cardiomyopathy in male patients is characterized by left ventricular (LV) hypertrophy, impaired myocardial function, and subsequent progressive myocardial fibrosis. In contrast, the occurrence of these 3 cardiomyopathic hallmarks in female patients remains unknown. METHODS: In 104 patients (58 females, age 42 ± 16 years; 46 males, age 42 ± 13 years) with genetically proven Fabry disease, LV hypertrophy, regional myocardial deformation and myocardial fibrosis were assessed by standard echocardiography, strain rate imaging, and cardiac magnetic resonance (CMR) imaging-guided late enhancement (LE). RESULTS: In men, end-diastolic left ventricular wall thickness (LVWT) ranged from 6 to 19.5 mm (LV mass CMR 55 to 200 g/m(2)), and LE was never seen with LVWT <12 mm (LV mass <99 g/m(2)). In contrast in female patients, LVWT ranged from 5 to 15.5 mm, LV mass ranged from 39 to 146 g/m(2), and LE was already detectable with an LVWT of 9 mm (LV mass 56 g/m(2)). When LV mass was examined in CMR, LE was detected in 23% of the female patients without hypertrophy (n=9), whereas LE was never seen in male patients with normal LV mass. LE was always associated with low systolic strain rate, but the severity of impairment was independent of LVWT in female patients (lateral strain rate in patients with LV hypertrophy with LE -0.7 ± 0.2 s(-1); patients without LV hypertrophy with LE -0.8 ± 0.2 s(-1); p=0.45). CONCLUSIONS: In contrast to male patients, the loss of myocardial function and the development of fibrosis do not necessarily require myocardial hypertrophy in female patients with Fabry disease. Thus, in contrast to actual recommendations, initial cardiac staging and monitoring should be based on LV hypertrophy and on replacement fibrosis in female patients with Fabry disease.

Feasibility of power contrast injections and bolus triggering during CT scans in oncologic patients with totally implantable venous access ports of the forearm.

BACKGROUND: Conventional totally implantable venous access ports (TIVAPs) are not approved for power contrast injections but often remain the only venous access site in oncologic patients. Therefore, these devices can play an important role if patients with a TIVAP are scheduled for a contrast-enhanced computed tomography (ceCT) as vascular access may become more difficult during the course of chemotherapy. PURPOSE: To evaluate the feasibility and safety of power injections in conventional TIVAPs in the forearm and to analyze the feasibility of bolus triggering during CT scans. MATERIAL AND METHODS: In this retrospective study we analyzed 177 power injections in 141 patients with TIVAPs in the forearm. Between October 2008 and March 2010 all patients underwent power injections (1.5 mL/s, 150 psi) via the TIVAP for ceCT because conventional vascular access via a peripheral vein had failed. Adequate functioning and catheter's tip location after injection were evaluated. Peak injection pressure and attenuation levels of aorta, liver and spleen were analyzed and compared with results of 50 patients who were injected via classical peripheral cannulas (3 mL/s, 300 psi). Feasibility of automatic scan initiation was evaluated. In vitro the port was stressed with 5 mL/s (300 psi). RESULTS: One TIVAP showed tip dislocation with catheter rupture. Three (2.1%) devices were explanted owing to assumed infection within 4 weeks after the injection. Mean injection pressure was 121.9 +/-24.1 psi. Triggering with automatic scan initiation succeeded in 13/44 (29.6%) scans. Injection via classical cannulas resulted in significantly higher enhancement (p < 0.05). In vitro the port system tolerated flow rates of up to 5 mL/s, injection pressures of up to 338 psi. CONCLUSION: Power injection is a safe alternative for patients with TIVAPs in the forearm if classic vascular access ultimately fails. Triggering was successful in one-third of the attempts. Image quality in the arterial phase scan may be hampered. In vitro results suggest that the device tolerates even higher flow rates.

Cardiac magnetic resonance imaging findings in 20-year survivors of mediastinal radiotherapy for Hodgkin's disease.

PURPOSE: The recognition of the true prevalence of cardiac toxicity after mediastinal radiotherapy requires very long follow-up and a precise diagnostic procedure. Cardiac magnetic resonance imaging (MRI) permits excellent quantification of cardiac function and identification of localized myocardial defects and has now been applied to a group of 20-year Hodgkin's disease survivors. METHODS AND MATERIALS: Of 143 patients treated with anterior mediastinal radiotherapy (cobalt-60, median prescribed dose 40 Gy) for Hodgkin's disease between 1978 and 1985, all 53 survivors were invited for cardiac MRI. Of those, 36 patients (68%) presented for MRI, and in 31 patients (58%) MRI could be performed 20-28 years (median, 24) after radiotherapy. The following sequences were acquired on a 1.5-T MRI: transversal T1-weighted TSE and T2-weighted half-fourier acquisition single-shot turbo-spin-echo sequences, a steady-state free precession (SSFP) cine sequence in the short heart axis and in the four-chamber view, SSFP perfusion sequences under rest and adenosine stress, and a SSFP inversion recovery sequence for late enhancement. The MRI findings were correlated with previously reconstructed doses to cardiac structures. RESULTS: Clinical characteristics and reconstructed doses were not significantly different between survivors undergoing and not undergoing MRI. Pathologic findings were reduced left ventricular function (ejection fraction <55%) in 7 (23%) patients, hemodynamically relevant valvular dysfunction in 13 (42%), late myocardial enhancement in 9 (29%), and any perfusion deficit in 21 (68%). An association of regional pathologic changes and reconstructed dose to cardiac structures could not be established. CONCLUSIONS: In 20-year survivors of Hodgkin's disease, cardiac MRI detects pathologic findings in approximately 70% of patients. Cardiac MRI has a potential role in cardiac imaging of Hodgkin's disease patients after mediastinal radiotherapy.

Cardiac energy metabolism is disturbed in Fabry disease and improves with enzyme replacement therapy using recombinant human galactosidase A.

AIMS: In vitro studies have shown impairment of energy metabolism in cardiac fibroblasts from Fabry patients. A recent in vivo study reported an association between cardiac energy metabolism and increased myocardial mass in Fabry patients. We therefore assessed possible disturbances of cardiac energy metabolism in Fabry patients by in vivo (31)P-MR-spectroscopy. Additionally, the effect of enzyme replacement therapy (ERT) on cardiac energetics was tested. METHODS AND RESULTS: Twenty-three patients (41 ± 9 years; 10 females) with genetically proven Fabry disease were examined with a 1.5 T Scanner, and compared with an age-matched healthy control group. Eight patients underwent ERT and had follow-up examinations after 3 and 14 months. The high-energy phosphate molecules phosphocreatine (PCr) and adenosine triphosphate (ATP) were quantified in localized 31P-spectra by SLOOP (spectral localization with optimum point spread function). Cine- and late gadolinium enhancement (LGE) studies were also performed. When compared with healthy controls, Fabry patients demonstrated reduced PCr- (6.1 ± 1.9 vs. 8.8 ± 2.6 mmol/kg; P = 0.003) and ATP concentrations (3.9 ± 1.5 vs. 4.6 ± 1.0 mmol/kg; P = 0.048). During ERT, PCr concentrations increased (7.1 ± 1.5 mmol/kg vs. 6.1 ± 1.9; P < 0.05) and left ventricular mass decreased (215 ± 55 vs. 185 ± 45 g; P = 0.012). Disturbances in cardiac energetics were not correlated to the presence or absence of cardiac fibrosis on LGE. CONCLUSION: Cardiac energy metabolism is disturbed in Fabry disease; this may play an important role in the pathogenesis of Fabry cardiomyopathy. Enzyme replacement therapy ameliorates energetic depression.

Explantation of totally implantable venous access ports of the forearm: reasons for removal and observed complications.

PURPOSE: To evaluate indications for, and complications during, explantation of interventionally placed totally implantable venous access ports (TIVAPs) of the forearm. BACKGROUND: Many studies analyze the explantation procedure of pectorally placed TIVAPs. The literature on TIVAPs in the forearm is limited, and the explantation procedure of these devices in the forearm has not been sufficiently evaluated yet. METHODS: We retrospectively reviewed the archives of our institute between May 2006 and May 2009 and identified 850 TIVAPs that had been implanted in the forearm. Of these TIVAPs, 145/850 (80 in women, 65 in men; mean age 52 years, range 15-82 years) were explanted during this period either by interventionists (n=109) or by general surgeons (n=36). RESULTS: Mean catheter survival was 322 days. Reasons for explantation were end of therapy (63.4%), infection (29.0%), thrombosis (3.4%), occlusion (1.4%), or dislocation (1.4%) of the TIVAP. Primary technical success rate was 97.2% for the surgical as well as for the interventional procedure. The overall success rate was 100%. The reasons for retrieval failure by interventionists (3/108) as well as by surgeons (1/36) were post-thrombotic adhesions of the port catheter to the blood vessel wall. CONCLUSIONS: Removal of TIVAPs of the forearm shows a high technical success rate and a low complication rate. End of therapy is the most common indication for explantation. There is a low risk of interventional removal failure with a resulting need for open surgery to remove the device.

Free breathing cardiac real-time cine MR without ECG triggering.

The increasing frequency of LV functional MRI studies demands for faster methods and for more comfort for the patient. We tested, whether real-time (RT) non ECG triggered MRI allows a considerable shortening of examination time in high reproducibility. RT and standard ECG-triggered breathhold cine MRI was acquired in 9 volunteers and 21 patients. Differences between both methods were assessed by Bland-Altman analyses including variability studies. Compared to standard cine MRI, RT decreased data acquisition time by more than the factor of ten. RT produced comparable results (e.g. EF in %: +0.67 [-5.63, 6.97]) except for a slight overestimation of LV mass. Interstudy and intraobserver variability of RT cine showed a low variability. Consequently, free-breathing RT cine proved to be a reliable and suitable tool for clinical routine and may be particularly relevant in patients with sub-optimal breath-holding ability and arrhythmia.

Evaluation of the nephrotoxicity of iodixanol in patients with predisposing factors to contrast medium induced nephropathy referred for contrast enhanced computed tomography.

To determine the risk of developing contrast induced nephropathy (CIN) in intermediate-risk patients receiving iodixanol, an iso-osmolar, dimeric non-ionic contrast agent, for CT in a clinical setting. Hundred consecutive patients referred for a contrast enhanced CT with a serum creatinine concentration>1.1mg/dl and/or a glomerular filtration rate (GFR)<90ml/min were included. Exclusion criteria were a serum creatinine>2.0mg/dl and a GFR<30ml/min or concurrent nephrotoxic agents. Between 60 and 140ml (mean 97+/-42ml) iodixanol (320mgI/ml) were administered at a flow of 2.5-3ml/s. Hydration with 500ml NaCl i.v. was performed before and after contrast injection. Follow-up was completed in 99 patients (age, 64+/-13 years, 68 men). CIN was defined as increase in serum creatinine concentration +0.5mg/dl or >25% above baseline within 72h after contrast administration. Serum creatinine concentration and GFR were 1.40+/-0.22, 1.29+/-0.29, and 1.26+/-0.29mg/dl and 52.2+/-13.9, 51.3+/-21.1, and 51.5+/-15.1ml/min on days 0, 3, and 7, respectively. Three out of 99 (3%) patients who received 90-110ml iodixanol revealed a CIN on day 3 without persistence on day 7. No specific therapy was needed. One out of 99 patients reported an exanthema on days 3 and 7. With the use of iodixanol in intermediate-risk patients, 3% of the patients develop CIN on day 3 without need for a specific therapy or persistence on day 7.

Energetic differences between viable and non-viable myocardium in patients with recent myocardial infarction are not an effect of differences in wall thinning- a multivoxel (31)P-MR-spectroscopy and MRI study.

To evaluate multivoxel (31)P-MR spectroscopy (MRS) for assessment of energy metabolism in patients with myocardial infarction (MI) in correlation to left ventricular (LV) wall thickness and the outcome of revascularization. Thirty patients with subacute anterior myocardial infarction and planned revascularization were enrolled. 3D-chemical shift imaging was applied to determine PCr/ATP ratios in two areas: infarcted/anterior and noninfarcted/septal myocardium. MRI was used to evaluate LV function and wall thickness, and was repeated 6 months after revascularization to assess myocardial viability. Fifteen volunteers were controls. Fifteen patients showed normalization of wall motion abnormalities after revascularization (Group 1; viable), 15 not (Group 2; non-viable). Regarding infarcted/anterior myocardium, Group 2 had lower PCr/ATP ratios (0.81 +/- 0.60 vs 1.17 +/- 0.25), and PCr/ATP ratios were reduced in both groups compared to controls (1.45 +/- 0.29). Regarding noninfarcted/septal myocardium, again Group 2 had lower ratios (0.93 +/- 0.53 vs 1.31 +/- 0.38); however, compared to controls (1.51 +/- 0.32) a reduction of PCr/ATP ratios was only found in Group 2. For both myocardial regions, no correlations between PCr/ATP ratios and LV wall thickness were detected. The more severe energetic alteration in irreversibly damaged myocardium is not an effect of differences of wall thinning. Additional alterations of noninfarcted, adjacent myocardium can be detected.

Impact of enzyme replacement therapy on cardiac morphology and function and late enhancement in Fabry's cardiomyopathy.

The present study evaluated the evolution of cardiac morphology, function, and late enhancement as a noninvasive marker of myocardial fibrosis, and their inter-relation during enzyme replacement therapy in patients with Fabry's disease using magnetic resonance imaging and color Doppler myocardial imaging. Late enhancement, which was present in up to 50% of patients, was associated with increased left ventricular mass, the failure of a significant regression of hypertrophy during enzyme replacement therapy, and worse segmental myocardial function. Late enhancement may predict the effect of enzyme replacement therapy on left ventricular mass and cardiac function.

Time course of 23Na signal intensity after myocardial infarction in humans.

Experimental studies demonstrated persistently increased 23Na content in nonviable myocardium post-myocardial infarction (MI). We hypothesized that nonviable myocardium in humans would show elevated 23Na content at all stages of infarct development, and therefore could be imaged with 23Na MRI. Ten patients were examined on days 4, 14, and 90 after infarction, and five of these patients participated in a 12-month follow-up. Double angulated short-axis cardiac 23Na images were obtained with the use of a 23Na surface coil and an ECG-triggered, 3D gradient-echo sequence. 1H T2-weighted imaging (N = 9) was performed on days 4, 14, and 90. Wall motion was assessed by cine MRI, and the infarct size was determined by late enhancement on day 90. The 23Na signal intensity (SI) of infarcted myocardium was expressed as the percentage increase over 23Na SI of noninfarcted myocardium. All of the patients showed an area of elevated SI on 23Na and 1H T2-weighted images that correlated with wall motion abnormalities and late enhancement. 23Na SI was highest on day 4. It then decreased until day 90, but remained elevated (39% +/- 18%, 31% +/- 17%, 28% +/- 13% on days 4, 14, and 90, respectively, P = 0.001). No further decrease was found 1 year after infarction (25% +/- 7%, P = 0.89 vs. day 90). 1H T2-weighted SI decreased between days 4 and 14, but on day 90 only six of nine patients had a residual elevated SI. Thus, 23Na SI is elevated in nonviable infarction at all time points following MI, and 23Na MRI may become a suitable technique for imaging nonviable myocardium in humans.