Non-invasive imaging of cardiac electrophysiology in a cardiac resynchronization therapy defibrillator patient with a quadripolar left ventricular lead.

AIMS: The present study was aimed to assess epi- and endocardial ventricular electroanatomical activation during cardiac resynchronization therapy (CRT) by means of non-invasive imaging of cardiac electrophysiology (NICE) in a patient with a novel quadripolar LV lead. METHODS AND RESULTS: Non-invasive imaging of cardiac electrophysiology is a novel imaging tool which works by fusing data from high-resolution electrocardiogram (ECG) mapping with a model of the patient's individual cardiothoracic anatomy created from magnetic resonance imaging. This was performed in a cardiac resynchronization therapy defribrillator (CRT-D) patient with a quadripolar left ventricular (LV) lead. Beat-to-beat endocardial and epicardial ventricular activation sequences were computed using NICE during intrinsic conduction as well as during different pacing modes with different LV and biventricular (biV) pacing vectors. The spatial resolution of NICE enabled discrimination of the different pacing vectors during LV and biV pacing. Biventricular pacing resulted in a marked shortening of the total activation duration (TAD) of both ventricles when compared with intrinsic conduction and RV and LV pacing. CONCLUSION: Non-invasive imaging of cardiac electrophysiology facilitates non-invasive imaging of ventricular activation, which may be useful in CRT patients to locate the area of latest ventricular activation as the target area for LV lead placement. Moreover, especially in non-responders to CRT NICE may be further useful to determine the best electrical repositioning option.

Cardiac troponin T and creatine kinase predict mid-term infarct size and left ventricular function after acute myocardial infarction: a cardiac MR study.

PURPOSE: To assess the relation of cardiac troponin T (cTnT) and creatine kinase (CK) release with infarct size and left ventricular function evaluated during the subacute phase as well as four months after acute myocardial infarction (AMI) by contrast-enhanced MRI (CE-MRI). MATERIALS AND METHODS: CMR of 80 patients (68 male, mean age 54.2 ± 11.7 years) was performed within 8 days and 4 months after first acute ST-elevation AMI with successful primary angioplasty. CK and cTnT concentrations were determined serially from admission to day 4 after symptom onset. RESULTS: All single time-points, estimated average release and peak concentrations of CK and cTnT markers correlated significantly with acute and mid-term infarct size (r = 0.43 to 0.79, all P < 0.001), ejection fraction (EF%) (r = -0.42 to -0.58, all P < 0.002) as well as with end-systolic volume (ESV) (r = 0.32 to 0.57, all P < 0.002) at all times of assessment. Patients with cTnT concentrations below the cutoff value of 3.26 µg/L measured 48 h after AMI-related symptom onset had a significant improvement in global (EF: P < 0.0001) myocardial function during the study period, whereas in those with cTnT ≥ 3.26 µg/L, functional recovery did not occur (P = 0.09). CONCLUSION: All single, mean and maximum concentrations of cTnT and CK measured within the first 4 days after AMI permit an accurate prediction of infarct size and left ventricular function as determined in the acute phase as well as four months after AMI by CE-MRI.

Kidney fusion anomalies revisited: clinical and radiological analysis of 209 cases of crossed fused ectopia and horseshoe kidney.

OBJECTIVE: To analyse the morphological appearance of horseshoe kidneys (HKs) and crossed fused ectopia (CFE) and to assess the frequency and clinical significance of associated anomalies and diseases. PATIENTS AND METHODS: The findings and images of 209 patients with fused kidneys (FKs) were reviewed; in all, 244 scans from computed tomography (CT), 233 ultrasonograms and 89 micturition cysto-urethrograms, urograms, magnetic resonance images and angiograms were taken. RESULTS: HKs (found in one of 474 abdominal CT scans) and CFEs (found in one of 3078 CT scans) showed a high variability of vasculature that could not be classified. However, some generalized conclusions were possible about the renal vasculature (430 arteries in 103 kidneys). Variants of the most cephalad artery of both sides were rare. The second artery on the right had a pre-caval course. The origins of vessels located further caudal were more ventral. CFEs were anatomically different from HKs with respect to lower position, greater axial rotation, smaller pelvic width, more caudal origin, and fewer vessels, but not in accompanying anomalies. Severe anomalies or malformations were found in 23% of patients, with half of them in the urogenital system. Malformations were found considerably more often in children than in adults. There was no increased incidence of diseases such as stones or inflammation of the renal pelvis. CONCLUSION: Concomitant anomalies and diseases were equally frequent for HK and CFE, but less frequent than generally assumed. Individual cases of complex anatomical situations require special examination strategies, and CT appears to be the most reliable imaging method.

A method for calcium quantification by means of CT coronary angiography using 64-multidetector CT: very high correlation with Agatston and volume scores.

To find out whether calcium scoring of the coronary arteries (CAC scoring) could be carried out with a CT angiography of the coronary arteries (CTCA) in a single CT data acquisition. The Agatston and V130 scores for 113 patients were assessed. A calcium volume score (V600 score) was compiled from the CTCA data sets. Intra- and interobserver correlations were excellent (rho > 0.97). The intra- and interobserver repeatability coefficients were extremely low, increasing in magnitude from the V600 score to the V130 and Agatston scores. The V600 score underestimates the coronary calcium burden. However, it has a linear relation to the Agatston and V130 scores. Thus, they are predictable from the values of the V600 score. The V600 score shows a linear relation to the classic CAC scores. Due to its extremely high reliability, the score may be a feasible alternative for classic CAC scoring methods in order to reduce radiation dosages.

Comparison of wall thickening and ejection fraction by cardiovascular magnetic resonance and echocardiography in acute myocardial infarction.

OBJECTIVES: The purpose of this study was to compare cardiovascular magnetic resonance (CMR) and echocardiography (echo) in patients treated with primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) with emphasis on the analysis of left ventricular function and left ventricular wall motion characteristics. METHODS: We performed CMR and echo in 52 patients with first AMI shortly after primary angioplasty and four months thereafter. CMR included cine-MR and T1-weighted first-pass and late-gadolinium enhancement (LGE) sequences. Global ejection fraction (EF(CMR), %) and regional left ventricular function (systolic wall thickening %, [SWT]) were determined from cine-MR images. In echo the global left ventricular function (EF(echo), %) and regional wall motion abnormalities were determined. A segment in echo was scored as "infarcted" if it was visually > 50% hypokinetic. RESULTS: EF(echo) revealed a poor significant agreement with EF(CMR) at baseline (r: 0.326; p < 0.01) but higher correlation at follow-up (r: 0.479; p < 0.001). The number of infarcted segments in echocardiography correlated best with the number of segments which showed systolic wall thickening < 30% (r: 0.498; p < 0.001) at baseline and (r: 0.474; p < 0.001) at follow-up. Improvement of EF was detected in both CMR and echocardiography increasing from 44.2 +/- 11.6% to 49.2 +/- 11% (p < 0.001) by CMR and from 51.2 +/- 8.1% to 54.5 +/- 8.3% (p < 0.001) by echocardiography. CONCLUSION: Wall motion and EF by CMR and echocardiography correlate poorly in the acute stage of myocardial infarction. Correlation improves after four months. Systolic wall thickening by CMR < 30% indicates an infarcted segment with influence on the left ventricular function.

Phosphorus-31 two-dimensional chemical shift imaging in the myocardium of patients with late onset of Friedreich ataxia.

PURPOSE: Friedreich ataxia (FRDA) is characterized by GAA expansions in the intron 1 of the frataxin gene correlating with disease onset and progression as well as cardiac affection. Accordingly, FRDA patients with early disease onset show a clear impairment of mitochondrial function in the myocardium. The purpose of this study was to investigate cardiac function and high-energy phosphate metabolism in FRDA patients with late disease onset. PROCEDURES: Using a 1.5 T magnetic resonance scanner, cardiac phosphorus-31 two-dimensional chemical shift imaging was performed in ten patients (seven male, three female) with a late onset of FRDA and in 35 healthy, male controls. Ejection faction (EF) and interventricular septum thickness (IST) were determined by echocardiography. RESULTS: The differences in left ventricular phosphocreatine (PCr) to beta-adenosine triphosphate (beta-ATP) ratios between both groups were not significant. FRDA patients had increased ISTs (10.8+/-1.6 vs. 9.7+/-0.9 mm; p=0.048), which correlated significantly with the left ventricular PCr to beta-ATP ratios (r= -0.644; p=0.04), and decreased EFs (52.24+/-7.72% vs. 64.09+/-4.25%; p=0.001) compared to normal controls. CONCLUSIONS: In contrast to FRDA patients with early disease onset, our patients collective exhibited a normal, probably compensated cardiac mitochondrial function, whereby IST and EF were mildly altered.

Yo-yo reflux in an incomplete duplex system causing severe hydronephrosis in a patient with contralateral renal agenesis.

This is a report of a case of a 26-year-old patient suffering from progressive renal insufficiency with a neurogenic bladder disorder due to a lipomyelomeningocele. She had renal agenesis on the left side and grade III hydronephrosis of both segments of a right duplex kidney with a bifid ureter joining further distal to the kidney. Both ureters were dilated. The cause was found to be a yo-yo reflux between the two halves of the kidney. Following bladder augmentation and pyelopyelostomy, renal insufficiency improved to stage III and has now been stable for four years. Due to the contralateral renal agenesis, the case is a unique illustration of the functional effect of the yo-yo reflux and pyelopyelostomy.

Congenital proximal radioulnar synostosis associated with bilateral hypoplasia of the scaphoid bone, bilateral os lunatotriquetrum, and anomalies of the carpometacarpal complex.

We describe a unique case of bilateral os lunatotriquetrum associated with bilateral hypoplasia of the scaphoid bone. On both sides, the medial carpi were in a single row. The capitate bone occupied the lunate position, whereas the lunatotriquetral bone was displaced ulnarly and tilted. The capitate thus articulated with the radius and metacarpal bones, consistent with carpal collapse. In addition, there was congenital proximal radioulnar synostosis on the left side.

A rare case of an acute soleus arcade syndrome complicated by a ganglion cyst: diagnosis by dynamic ultrasound.

The soleus arcade syndrome is a rare compression neuropathy of the tibial nerve that often remains undiagnosed due to low clinical awareness and difficult diagnosis. We present the case of a female patient admitted with acute worsening of a pre-existing sensory tibial neuropathy and acute tibial nerve palsy after knee joint injection. After a knee magnetic resonance imaging remained non-diagnostic, dynamic ultrasonography was performed. Constriction by the soleus arcade and proximal swelling of the tibial nerve could be demonstrated during plantarflexion of the ankle by means of a dynamic examination in the standing patient. The patient underwent surgery and recovered fully. This proposed diagnostic approach can be used to identify soleus arcade syndrome by ultrasound.

Isolated numerical skills in posterior cortical atrophy--an fMRI study.

Posterior cortical atrophy (PCA) is characterized by bilateral parieto-occipito-temporal atrophy and hypometabolism. Neuropsychological impairments include complex visual disturbances, alexia, agraphia, finger agnosia, right-left disorientation and dyscalculia. A recent case study reported severe numerical deficits with some selectively preserved numerical skills in a patient affected by PCA [Delazer, M., Karner, E., Zamarian, L., Donnemiller, E., & Benke, T. (2006). Number processing in posterior cortical atrophy--a neuropsycholgical case study. Neuropsychologia]. In a functional magnetic resonance imaging (fMRI) study brain activation patterns related to these selectively preserved numerical skills were analyzed. Recitation of multiplication tables and counting forward were contrasted to word recitation in a block design. Contrasts between experimental conditions and control condition yielded significant activation of inferior and medial temporal structures. Since numerical processing is generally associated with parietal activation, it was hypothesized that preserved brain structures would compensate for the functional deficits.

Neural correlates of verbal semantic memory in patients with temporal lobe epilepsy.

Functional imaging data suggest that the core network engaged in verbal semantic memory (SM) processing encompasses frontal and temporal lobe structures, with a strong left lateralization in normal right handers. The impact of long term temporal lobe epilepsy (TLE) on this network has only partly been elucidated. We studied verbal SM in 50 patients with chronic, intractable TLE (left TLE=26, right TLE=24) and 35 right handed normal controls using a verbal fMRI semantic decision paradigm. All patients had language lateralized to the left hemisphere, as verified by the intracarotid amobarbital procedure. Within and between group analyses showed remarkable, group-specific activation profiles. The control group activated frontal and temporal areas bilaterally, with a strong left predominance. Left TLE patients showed a shift of activations of left frontal and medial temporal areas to homologous regions in the right hemisphere. Furthermore, left TLE subjects utilized subcortical structures such as the thalamus and putamen to accomplish the verbal SM task. Contrastively, the activation pattern of right TLE patients resembled that of normal controls, but exhibited "hypofrontality" with a shift from frontal to posterior regions in the temporal, parietal and occipital lobe. Our results show that chronic epileptic activity originating from temporal seizure foci is associated with an alteration of neural circuits which support semantic language processing and that side of seizure focus has a specific impact on the resulting activation network. These findings presumably result from morphological changes and from functional reorganization which are both inherent to chronic TLE.

Predictors of carpal tunnel syndrome: accuracy of gray-scale and color Doppler sonography.

OBJECTIVE: The purpose of this study was to retrospectively assess the accuracy of gray-scale and color Doppler sonography in the diagnosis of carpal tunnel syndrome. MATERIALS AND METHODS: A total of 206 wrists in 151 patients with a clinical suspicion of carpal tunnel syndrome were examined with high-resolution sonography using a 7-15-MHz linear array transducer. The presence of median nerve swelling, edema, and flattening and increased bowing of the flexor retinaculum was evaluated with gray-scale sonography, and the presence of nerve hypervascularization was evaluated with color Doppler sonography. Sensitivity and specificity were calculated for each sonographic feature in comparison with nerve conduction studies as the standard of reference. Multivariate logistic regression analysis was used to determine variables predictive of carpal tunnel syndrome. RESULTS: Carpal tunnel syndrome was confirmed in 172 wrists at nerve conduction studies. A median nerve cross-sectional area of at least 0.11 cm2 was calculated as a definition of median nerve swelling. In comparison with nerve conduction studies, nerve swelling showed the highest accuracy (91%) among gray-scale sonography criteria, and the presence of intraneural hypervascularization showed the highest accuracy (95%) among all sonography criteria. Logistic regression analysis showed that nerve hypervascularization was the only variable that independently predicted median nerve entrapment (odds ratio, 16.4; 95% confidence interval, 8.7-31.1; p <0.001). CONCLUSION: Color Doppler sonography is more accurate than gray-scale sonography for characterizing median nerve involvement in patients with suspected carpal tunnel syndrome.

Voxel-based morphometry in narcolepsy.

BACKGROUND AND PURPOSE: Voxel-based morphometry (VBM) is a magnetic resonance imaging (MRI)-based indirect volumetry, which allows the investigation of the entire brain without restriction of predefined regions-of-interest. Recent studies using this technique reported controversial results in patients with narcolepsy. PATIENTS AND METHODS: In this study, 12 patients with narcolepsy according to the criteria of the International Classification of Sleep Disorders were compared to 12 age-matched controls with normal MR images using VBM. Sex and global differences in voxel intensities were used as confounding covariates. RESULTS: Significant gray matter loss was found in the right prefrontal and frontomesial cortex of patients with narcolepsy. White matter comparison revealed no significant changes in patients or controls. The comparison of cerebrospinal fluid partition detected an enlargement of subarachnoidal space of controls close to the prefrontal cortex. CONCLUSIONS: The volume reduction of gray matter in narcoleptic patients could indicate a disease-related atrophy pattern. However, the results of VBM studies in narcolepsy are contradictory. A possible systematic bias due to inhomogeneous patient groups, stimulant medication history or pre-statistical image processing must be considered. We suggest that studies with drug-naive patients and/or region-of-interest-based volumetric studies should be performed in areas defined by VBM.

Medial temporal lobe activation during semantic language processing: fMRI findings in healthy left- and right-handers.

Medial temporal lobe (MTL) areas are well known to serve episodic memory functions; their contribution to semantic memory has been occasionally noticed but not studied in detail. In the present fMRI study, 35 right-handed and 35 left-handed healthy subjects performed a semantic decision paradigm during which subjects heard spoken concrete nouns designating objects and had to decide on whether these objects were available in the supermarket and cost lest then a certain amount of money. The control paradigm consisted of sequences of low and high tones where subjects had to decide whether a sequence contained two high tones. The resulting contrast activation of semantic decision versus tone decision involved neocortical temporal, parietal, and prefrontal areas. Additional significant, bilateral activations in the MTL, the hippocampal formation, and adjacent areas were found. The exact incidence and location of activation was studied in a single-subject analysis for all 70 subjects. At the chosen threshold of P<0.001, 94% of subjects showed activations in the MTL and inferior temporal lobe (ITL). Activations were found along the longitudinal axis of the MTL, including the hippocampal formation and the parahippocampal gyrus. In the ITL, parts of the fusiform and lingual gyri were activated. Activations were similar in right- and left-handers. We conclude from this study that the MTL and parts of the ITL can be added to the areas activated by semantic verbal memory processing.

Basal forebrain atrophy is a distinctive pattern in dementia with Lewy bodies.

We determined brain atrophy patterns in dementia with Lewy bodies and Alzheimer's disease using voxel-based morphometry, an indirect volumetry. Ten patients with dementia with Lewy bodies, 10 patients with Alzheimer's disease and 10 controls were included. All groups were matched for age; sex and global differences in voxel intensities were included as confounding covariates. We observed basal forebrain atrophy discriminating dementia with Lewy bodies from Alzheimer's disease. Compared to controls, atrophy of lateral prefrontal cortex and left premotor cortex was seen in dementia with Lewy bodies whereas atrophy of the medial temporal cortex, posterior parietal cortex, thalamus and temporo-occipital areas was observed in Alzheimer's disease. Atrophy of insular cortex was found in both patient groups.

Late microvascular obstruction after acute myocardial infarction: relation with cardiac and inflammatory markers.

OBJECTIVES: We sought to assess the relation of late microvascular obstruction (l-MVO) size as quantified by cardiac magnetic resonance (CMR) imaging with cardiac and inflammatory marker concentrations after acute myocardial infarction (AMI). METHODS: CMR was performed in 118 consecutive patients within 8 days after successful interventional reperfused first acute ST-elevation AMI. Infarct volumes and l-MVO sizes were calculated from late enhancement (LE) sequences and functional parameters were determined from short-axis cine MR sequences. Creatine kinase (CK) and cardiac troponin T (cTnT), high-sensitivity C-reactive protein (hs-CRP) as well as lactate dehydrogenase (LD) concentrations were determined serially from day 1 to day 4 after symptom onset. RESULTS: L-MVO was detected in 66/118 patients (55.9%) and comprised 18.2 ± 10% of infarct size and 4.7 ± 3% of left ventricle myocardial mass. Each single-point, peak and cumulative release concentration of cTnT (r=0.44 to 0.73, p<0.0001), CK (r=0.21 to 0.76, p<0.0001), LD (r=0.36 to 0.82, all p<0.0001) as well as hs-CRP single-point values as assessed from day 1 to day 4 and its peak and cumulative release concentrations (r=0.24 to 0.49, p<0.003) significantly correlated with l-MVO size. Receiver operating curve (ROC) analysis indicated a cut-off value of 4.7 µg/l cTnT to best identify the presence of l-MVO (area under the curve (AUC) 0.904; 95% CI: 0.85-0.95; p<0.0001). CONCLUSION: L-MVO sizes significantly correlate with cardiac and inflammatory marker concentrations as determined early after AMI. cTnT concentration of >4.7 µg/l could help to identify patients in whom l-MVO is present.

Patterns of myocardial perfusion in the acute and chronic stage after myocardial infarction: a cardiac magnetic resonance study.

OBJECTIVES: The aim of the present study was to monitor the microvascular perfusion damage in the acute and chronic stage after myocardial infarction (MI) using first-pass dynamic magnetic resonance imaging (MRI). Furthermore we compared improvement of myocardial microcirculation and function in infarcted and non-infarcted left midventricular segments over a 4 months period. MATERIALS AND METHODS: Cardiac magnetic resonance imaging (CMR) was performed in 46 consecutive patients within 8 days after successful reperfused first acute ST-elevation MI and 4 months thereafter. First-pass images were obtained by using Turbo-FLASH sequence during a bolus injection of Gd-based contrast agent. Signal-intensity-to-time (SIT) curves of 276 left ventricular myocardial segments were generated. Furthermore, infarct volumes as well as parameters of regional left ventricular function of corresponding segments were calculated. RESULTS: SIT curves highly significantly correlate with MI size (r=-0.57, r=-0.43 respectively; all p<0.0001) as well as with segmental wall thickening (SWT) of corresponding segments at baseline and follow-up scans (r=0.20, r=0.15 respectively; all p<0.02). SWT differ highly significantly between segments with and those without LE at baseline (p<0.003) and follow-up examinations (p<0.008), presenting either clear improvements at follow-up (all p<0.0001). In contrast, infarcted segments showing microvascular obstruction evidenced neither significant recovery of SIT nor of SWT (p=NS). CONCLUSION: Our data indicate a close relationship between MI size and myocardial perfusion as well as function. Beyond epicardial artery patency, the assessment of quantitative parameters of myocardial perfusion and contractile function with the help of CMR appears to be a useful tool for estimating myocardial recovery after acute MI.