Longitudinal Deformation of the Right Ventricle in Hypoplastic Left Heart Syndrome: A Comparative Study of 2D-Feature Tracking Magnetic Resonance Imaging and 2D-Speckle Tracking Echocardiography.

In hypoplastic left heart syndrome (HLHS), long-term outcome is closely related to right ventricular function. Echocardiography and magnetic resonance imaging (MRI) are routinely used for functional assessment. MRI 2D-tissue feature tracking (2D-FT) allows quantification of myocardial deformation but has not yet been applied to HLHS patients. We sought to investigate the feasibility of this technique and to compare the results to 2D-speckle tracking echocardiography (2D-STE). In routine MRI 2D anatomical four chamber view, cine images were recorded in 55 HLHS patients (median age 4.9 years [1.6, 17.0]). Regional and global peak systolic longitudinal strain (LS) and strain rate (LSR) were determined using 2D-FT software. Echocardiographic four chamber view was analyzed with 2D-STE. Visualization of all myocardial segments with MRI was excellent, regional, and global LS and LSR could be assessed in all data sets. In 2D-STE, 28% of apical segments could not be analyzed due to poor image quality. Agreement of 2D-FT MRI and 2D-STE was acceptable for global LS, but poor for global LSR. In MRI, regional LS was lower in the septal segments, while LSR was not different between the segments. GLS and GLSR correlated with ejection fraction (GLS: r = - 0.45 and r < 0.001, GLSR: r = - 0.34 and p = 0.01). With new post-processing options, the assessment of regional and global LS and LSR is feasible in routine MRI of HLHS patients. For LS, results were comparable with 2D-STE. The agreement was poor for LSR, which might relate to differences in temporal resolution between the two imaging modalities.

[Cardiovascular magnetic resonance imaging in childhood - clinical indications and case studies]. / Kardiovaskuläre Magnetresonanztomografie im Kindesalter - klinische Indikationen und Beispiele.

In today's clinical practice cardiovascular magnetic resonance (CMR) imaging is increasingly used for assessment of congenital and acquired heart disease in children. CMR complements echocardiography and provides a noninvasive alternative to diagnostic cardiac catheterization. In contrast to echocardiography, CMR is not limited by acoustic windows, and unlike cardiac catheterization, CMR lacks ionizing radiation. Contiguous three and four dimensional data sets allow to display cardiac and thoracic vessel anatomy in any desired imaging plane. These characteristics provide unique images for the complete depiction of the pathological anatomy in particular in congenital heart disease. Furthermore CMR is also used for assessment of cardiac function, blood-flow measurements, tissue characterization, and, more recently, for evaluation of myocardial perfusion and viability. The following article reviews CMR indications in pediatric cardiology by means of clinical examples.

[3 tesla magnetic resonance imaging in children and adults with congenital heart disease]. / 3-Tesla-Magnetresonanztomographie zur Untersuchung von Kindern und Erwachsenen mit angeborenen Herzfehlern.

Cardiovascular magnetic resonance imaging (CMR) has become a routinely used imaging modality for congenital heart disease. A CMR examination allows the assessment of thoracic anatomy, global and regional cardiac function, blood flow in the great vessels and myocardial viability and perfusion. In the clinical routine cardiovascular MRI is mostly performed at field strengths of 1.5 Tesla (T). Recently, magnetic resonance systems operating at a field strengths of 3 T became clinically available and can also be used for cardiovascular MRI. The main advantage of CMR at 3 T is the gain in the signal-to-noise ratio resulting in improved image quality and/or allowing higher acquisition speed. Several further differences compared to MRI systems with lower field strengths have to be considered for practical applications. This article describes the impact of CMR at 3 T in patients with congenital heart disease by meanings of methodical considerations and case studies.

Catheter-based closure of atrial septal defects in the oval fossa with the Amplatzer device in patients in their first or second year of life.

OBJECTIVE: To assess feasibility, safety, and efficacy of the use of Amplatzer occluders in closure of atrial septal defects (ASD) in children in the first 2 years of life. BACKGROUND: Although scattered reports on such closure have been published, no agreement consists on the policy. METHODS: In 654 patients of all ages, closure was achieved in 632 (96.6%). Data were analyzed retrospectively in all 71 children where an attempt had been made to close the ASD before their second birthday. RESULTS: Median age and body weight were 17.2 months (range 3.9-23.8) and 10.0 kg (range 3.8-14.5), respectively. Median fluoroscopy time was 13.6 min and median device size 15 mm. Successful closure was achieved in 68 children (95.8%). Three times the procedure was aborted: in one, the device repeatedly straddled the septum; in the other two, a small left atrium restricted the movement of the left-sided disc. One device embolized and was reimplanted after retrieval. One infant with multiple disorders died 6 days after closure from acute sepsis probably unrelated to the procedure. No other complications occurred. Only trivial shunts closing with time were registered during follow-up. Symptomatic patients profited markedly from closure. CONCLUSION: The results and complications of ASD closure with the Amplatzer device in patients in their first 2 years of life compare favorably with procedures in older patients, provided that the size of the septum and the dimensions in the left atrium are taken into consideration when selecting the size of the device.

Ventricular function and ventriculo-arterial coupling after palliation of hypoplastic left heart syndrome: A comparative study with Fontan patients with LV morphology.

BACKGROUND: Conceptually the right ventricle (RV) is less suitable to support the Fontan circulation than the left (LV). After palliation of hypoplastic left heart syndrome (HLHS) involving aortic reconstruction during the Norwood procedure the RV is exposed to abnormal afterload. We studied ventricular function and ventriculo-arterial coupling in HLHS patients (RV) and Fontan patients with single LV morphology that did (LV+N) and did not (LV-N) undergo Norwood-type aortic reconstruction. METHODS: Eighty patients (55 RV, 8 LV+N, 17 LV- N) were simultaneously studied with the conductance-catheter and echocardiography 4.8 (0.9-22.9)years after Fontan completion. RESULTS: Ejection fraction (EF) was lowest in the HLHS group (RV 60.9±11.0 vs. LV+N 68.4±10.5 vs. LV-N 69.7±8.0, P=0.003) whereas end systolic elastance (Ees), i.e. ventricular contractility, and end diastolic stiffness (Eed) were highest (Ees: RV 3.38±2.2 vs. LV+N 2.3.±13.8 vs. LV-N 1.92±1.37mmHg/ml, P=0.02; Eed: RV 0.59±0.36 vs. LV+N 0.48±0.29 vs. LV-N 0.32±0.17mmHg/ml, P<0.02). Arterial elastance, a measure of afterload, was highest in HLHS patients and correlated positively with Ees and Eed and inversely with EF in the study cohort. Only long axis function analysis suggested superior ventricular function in HLHS patients whereas all other echocardiographic measures did not reveal any group differences. CONCLUSION: Ventricular contractility of the RV of HLHS patients is higher than that of the ventricle of Fontan patients with LV morphology. This likely reflects a physiological response to higher arterial elastance resulting from aortic arch reconstruction. Increased arterial elastance negatively impacts diastolic stiffness, which is higher in the systemic RV than LV.

Differential effect of Incobotulinumtoxin A on pain, neurogenic flare and hyperalgesia in human surrogate models of neurogenic pain.

BACKGROUND: The effectiveness of Botulinum-neurotoxin A (BoNT/A) to treat pain in human pain models is very divergent. This study was conducted to clarify if the pain models or the route of BoNT/A application might be responsible for these divergent findings. METHODS: Sixteen healthy subjects (8 males, mean age 27 ± 5 years) were included in a first set of experiments consisting of three visits: (1) Visit: Quantitative sensory testing (QST) was performed before and after intradermal capsaicin injection (CAPS, 15 µg) on one thigh and electrical current stimulation (ES, 1 Hz) on the contralateral thigh. During stimulation pain and the neurogenic flare response (laser-Doppler imaging) were assessed. (2) Four weeks later, BoNT/A (Xeomin® , 25 MU) was injected intracutaneously on both sides. (3) Seven days later, the area of BoNT/A application was determined by the iodine-starch staining and the procedure of the (1) visit was exactly repeated. In consequence of these results, 8 healthy subjects (4 males, mean age 26 ± 3 years) were included into a second set of experiments. The experimental setting was exactly the same with the exception that stimulation frequency of ES was increased to 4 Hz and BoNT/A was injected subcutaneously into the thigh, which was stimulated by capsaicin. RESULTS: BoNT/A reduced the 1 Hz ES flare size (p < 0.001) and pain ratings (p < 0.01), but had no effect on 4 Hz ES and capsaicin-induced pain, hyperalgesia, or flare size, regardless of the depth of BoNT/A injection (i.c./s.c). Moreover, i.c. BoNT/A injection significantly increased warm detection and heat pain thresholds in naive skin (WDT, Δ 2.2 °C, p < 0.001; HPT Δ 1.8 °C, p < 0.005). CONCLUSION: BoNT/A has a moderate inhibitory effect on peptidergic and thermal C-fibers in healthy human skin. SIGNIFICANCE: The study demonstrates that BoNT/A (Incobotulinumtoxin A) has differential effects in human pain models: It reduces the neurogenic flare and had a moderate analgesic effects in low frequency but not high frequency current stimulation of cutaneous afferent fibers at C-fiber strength; BoNT/A had no effect in capsaicin-induced (CAPS) neurogenic flare or pain, or on hyperalgesia to mechanical or heat stimuli in both pain models. Intracutaneous BoNT/A increases warm and heat pain thresholds on naïve skin.

Slow brushing reduces heat pain in humans.

BACKGROUND: C-tactile (CT) afferents are unmyelinated low-threshold mechanoreceptors optimized for signalling affective, gentle touch. In three separate psychophysical experiments, we examined the contribution of CT afferents to pain modulation. METHODS: In total, 44 healthy volunteers experienced heat pain and CT optimal (slow brushing) and CT sub-optimal (fast brushing or vibration) stimuli. Three different experimental paradigms were used: Concurrent application of heat pain and tactile (slow brushing or vibration) stimulation; Slow brushing, applied for variable duration and intervals, preceding heat pain; Slow versus fast brushing preceding heat pain. RESULTS: Slow brushing was effective in reducing pain, whereas fast brushing or vibration was not. The reduction in pain was significant not only when the CT optimal touch was applied simultaneously with the painful stimulus but also when the two stimuli were separated in time. For subsequent stimulation, the pain reduction was more pronounced for a shorter time interval between brushing and pain. Likewise, the effect was more robust when pain was preceded by a longer duration of brush stimulation. Strong CT-related pain reduction was associated with low anxiety and high calmness scores obtained by a state anxiety questionnaire. CONCLUSIONS: Slow brushing - optimal for CT activation - is effective in reducing pain from cutaneous heating. The precise mechanisms for the pain relief are as yet unknown but possible mechanisms include inhibition of nociceptive projection neurons at the level of the dorsal horn as well as analgesia through cortical mechanisms. SIGNIFICANCE: Slow brushing stimuli - optimal for activation of C-tactile fibres - can reduce pain from cutaneous heating. No such effect was seen with fast brushing or vibration. These observations indicate the role of C-tactile fibres in pain modulation.

Follow-up of advanced diabetic neuropathy: useful variables and possible pitfalls.

BACKGROUND: The course of advanced diabetic neuropathy (DN) is largely unknown. AIM: To find variables allowing the follow-up of late stages of DN. METHODS: Thirty diabetic patients with DN were observed. Patients were examined at intervals of 6 months over a period of 2 years. The compound muscle action potentials (CMAPs) were recorded in extensor digitorum brevis (EDB) and flexor hallucis brevis (FHB) muscles. Clinical severity of DN, nerve conduction studies (NCS), quantitative sensory testing (QST) and heart rate variability (HRV) were evaluated. The data were compared with age- and sex-matched controls. RESULTS: All measures were sensitive to the detection of DN. Significant deterioration during follow-up was exclusively found in CMAP analysis of the EDB (p<0.05) and FHB muscles (p<0.03). NCS, QST and HRV remained unchanged within the 2 years of observation. Coincidental changes might occur, if only two time points are chosen for followup. CONCLUSION: Our results indicate that ongoing axonopathy predominates in advanced DN. Repeated testing helps to minimize the impact of coincidental or chance changes in DN follow-up studies.

Zolmitriptan inhibits neurogenic inflammation and pain during electrical stimulation in human skin.

BACKGROUND: Triptans are agonists to 5-HT 1B/D/F receptors, which are present on nociceptive neurons not only within but also beyond the trigeminal system. The aim of this study was to investigate whether zolmitriptan interacts with peptidergic nociceptive afferents in human skin. METHODS: Twenty participants (13 women, median age: 25; interquartile range: 23-26 years) entered the randomized, double-blind, cross-over study. Electrically induced neurogenic flare and pain was assessed after either placebo or zolmitriptan on the ventral thigh. Mechanical pain thresholds were investigated at baseline and after electrical stimulation at the stimulation site. RESULTS: The size of the neurogenic flare (F = 10.9; p = 0.002) as well as electrically induced pain were significantly reduced by zolmitriptan (F = 4.46; p = 0.041). Moreover, electrically induced pinprick hyperalgesia was significantly decreased by zolmitriptan compared with placebo (F = 6.243; p = 0.017). CONCLUSIONS: Triptans may have effects outside of the trigeminal system and reduce electrically evoked neurogenic inflammation and pain in human skin.

Assessment of the neurogenic flare reaction in small-fiber neuropathies.

To improve sensitivity of the analysis of axon reflex flare reaction, the authors used a laser Doppler scanner and analyzed flare intensity and size induced by histamine iontophoresis simultaneously at the foot and thigh in patients with small-fiber neuropathy (n = 10) and controls (n = 9). Flare size, but not laser Doppler flux, clearly distinguished patients from controls at both locations (p < 0.01) and may be useful for evaluation of small-fiber neuropathies.

Distribution of myocardial beta-adrenoceptor subtypes and coupling to the adenylate cyclase in children with congenital heart disease and implications for treatment.

In congestive heart failure, down-regulation of myocardial beta-adrenoceptors (beta-AR) due to an elevated sympathetic tone is well known. In infancy and childhood, heart failure is usually related to congenital heart disease (CHD). Therefore, 71 samples of right atrial tissue of infants and children with CHD undergoing cardiac surgery were studied for beta-adrenoceptor density and distribution of the beta 1-/beta 2-AR subtypes. In 49 cases, the coupling of the beta-AR to the adenylate cyclase (AC) was examined. In a further study of 19 myocardial samples, AC was selectively stimulated with beta 1- or beta 2-AR whereas the other subtype was blocked by an antagonist. The following results were obtained: (1) Infants and children with severe acyanotic or cyanotic CHD had severely reduced beta-AR densities. (2) In most of the cases, the beta-AR down regulation is beta 1-subtype selective, but in critically ill newborns with congenital aortic valve stenosis or transposition of the great arteries, there is additional significant beta 2-AR down-regulation. In Fallot patients treated with the beta-antagonist propranolol, a significant increased beta-AR number compared with untreated Fallot patients was found. (3) beta-Adrenoceptor reduction in CHD is correlated with elevated noradrenaline plasma levels, thus proving a sympathetic dysregulation. (4) In CHD with moderate hemodynamic load, beta 2-AR coupling to AC was markedly more efficient than beta 1-AR coupling. The small number of myocardial beta 2-AR produced most of the cyclic adenosine monophosphate. (5) In severe acyanotic and cyanotic CHD, a partial decoupling of the beta 2-AR to the AC occurred.(ABSTRACT TRUNCATED AT 250 WORDS)

Botulinum Toxin A reduces neurogenic flare but has almost no effect on pain and hyperalgesia in human skin.

Botulinum toxin A (BoNT/A) has been used therapeutically to treat muscular hypercontractions and sudomotor hyperactivity. There is increasing evidence that BoNT/A might also have analgesic properties, in particular in headache. In the present investigation we tested the often cited hypothesis that BoNT/A-induced analgesia can be attributed to inhibition of neuropeptide release from nociceptive nerve fibers. In 15 healthy volunteers BoNT/A (5, 10, 20 mouse units BOTOX) or saline (contralateral side) was injected intracutaneously on the volar forearm. On day zero, the day of injection, no further tests were performed. We repeatedly elicited pain, mechanical hyperalgesia and neurogenic flare by transcutaneous electrical stimulation simultaneously on the BoNT/A and saline treated side on day 1, 2, 3, 7 and 14 after injection. Before each session, sweating and local anhidrosis was assessed by iodine starch staining.BoNT/A suppressed sweating as early as from the second day after injection (p < 0.001). The size of electrically induced flare was smaller on the BoNT/A treated arm (BoNT/A side: 21.46 cm(2) +/- 3.58, saline side 24.80 +/- 3.46, p < 0.005) and BoNT/A reduced electrically-induced pain by about 10 % (p < 0.001). However, hyperalgesia to pin-prick and allodynia after electrical stimulation were unchanged. In conclusion our results indicate that peripheral neuropeptide release is attenuated by BoNT/A. In contrast, the analgesic effect of BoNT/A was very limited. Therefore we assume that other than neuropeptide mechanisms must be important for BoNT/A induced pain relief in clinical pain syndromes.

A novel method for real-time magnetic marker monitoring in the gastrointestinal tract.

In internal medicine, a simple method for the functional examination of the gastrointestinal tract without the risk of radiation exposure is required. We describe a novel principle based on the monitoring of magnetic markers which meets these demands. Our method employs a special permanent magnet which is repeatedly aligned by a vertically oriented pulsed magnetic field. Due to this alignment, the marker position can be derived from the stray field components measured by commercial field sensors. Our method was evaluated by means of a 3D intestinal phantom. The monitoring procedure yielded the time course of the marker position as a 3D plot either in real-time or as a time-lapse movie. The spatial resolution, expressed by the mean square deviation, was better than 10 mm and is thus sufficiently high to distinguish between adjacent loops of the gut. The temporal resolution, i.e. the minimum time between two successive measurements, was about 1 s. The presented method has very moderate technical demands and allows us to monitor magnetic markers in real-time. The technique may be useful with respect to functional examination of the gastrointestinal tract. In pharmaceutical research, our method offers the opportunity for remote drug release at any position of the gut.

Intermediate-term clinical and hemodynamic results of the neonatal arterial switch operation for complete transposition of the great arteries.

We prospectively evaluated 49 consecutive hospital survivors of the arterial switch operation for complete transposition and intact ventricular septum by clinical examination, echocardiography, cardiac catheterization, 12-lead and 24-h Holter ECG. The mean length of follow-up was 40 +/- 18 months. Forty-six children are clinically asymptomatic without medication, 2 died due to coronary related left ventricular dysfunction 3 and 12 months after surgery, and 1 required reoperation because of severe bilateral pulmonary branch stenoses. Except for this case, cardiac catheterization (n = 23) revealed a mean gradient of only 17 +/- 8 mmHg between the right ventricle and distal pulmonary arteries. Left ventricular end-diastolic volume was within normal limits except for 2 cases with volumes slightly below normal, the mean ejection fraction was 78 +/- 5%, and end-diastolic and end-systolic ventricular shapes were normal. The mean cardiac index was 4.14 +/- 0.69 l/min/m2. Left ventricular end-systolic wall stress to velocity of fiber shortening relation was normal in all cases examined (n = 15), indicating normal myocardial contractility. Significant neoaortic valve insufficiency was never observed despite considerably enlarged aortic roots. Twenty-four-hour Holter ECG records (n = 46) provided no evidence of serious atrial arrhythmias, especially sinus node dysfunction. These encouraging intermediate-term results make the arterial switch operation the treatment of choice at present, for neonates with simple transposition.

Cardiac rhythm after Mustard repair and after arterial switch operation for complete transposition.

We compared the prevalence of arrhythmias among the first consecutive 45 patients with complete transposition (concordant atrioventricular and discordant ventriculo-arterial connexions) after arterial switch operation and the last 47 patients after Mustard repair in infancy. Both groups had 24-hour Holter electrocardiographic studies at similar periods of follow up (24 +/- 14 and 25 +/- 18 months). A second group of patients undergoing the Mustard procedure had been repaired at an older age before 1981. They were studied to determine the frequency of disturbances of rhythm during later postoperative follow-up (85 +/- 24 months). Symptomatic brady-/tachyarrhythmia syndrome never occurred after the arterial switch and only once in the group of patients repaired by the Mustard procedure in infancy, but developed at a late stage (69 +/- 28 months); five times in the group of patients having Mustard's repair at an older age. In addition, Holter monitoring did not detect bradyarrhythmias indicating sinus node dysfunction in a single patient after the arterial switch, but did so to a similar extent in both groups having the Mustard procedure (recent: n = 14; older: n = 18). Three cases of the group of older patients undergoing a Mustard operation developed complete atrioventricular block during follow-up. Normal findings were present in 93% of the cases after arterial switch, but in only 51% of the cases with a similar follow-up repaired by the Mustard procedure, and in 29% of the group having the Mustard repair at an older age.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term results after surgical correction of atrioventricular septal defects.

OBJECTIVE: Review of the results of surgical correction of atrioventricular septal defects (AVSD), identification of risk factors for mortality and failure of left AV valve repair and determination of the impact of cleft closure on postoperative AV valve function. METHODS: Between 1975 and 1995, 121 consecutive patients (55 males, 66 females) underwent surgery for biventricular correction of AVSD with a median age of 1.2 years and a median weight of 7.6 kg. Sixty-five patients had a complete AVSD, 17 patients an intermediate type, and 39 patients a partial AVSD. The left AV valve (MV) cleft was closed in 53 patients (43.8%). The mean follow-up time is 7.2+/-4.6 years. RESULTS: Actuarial survival of the whole group after 1 year was 80%, after 10 and 20 years 78 and 65%, respectively. There were 18 early deaths (7-day mortality, 10.7%; 30-day mortality, 14.9%) and eight late deaths. In a univariate analysis, risk factors for early or late death were diagnosis of complete AVSD (P=0.006), no cleft closure (P=0.024), postoperative complications (P<0.0001), age <1.2 years (P=0.017), weight <7.6 kg (P=0.002), PA/Ao pressure ratio >0.7 (P<0.0001), and ECC time >110 min (P=0.002). In the multivariate analysis, postoperative complications (P=0.003) and PA/Ao pressure ratio >0.7 (P=0.001) had parallel effects on the postoperative risk for mortality. Moderate or severe MV regurgitation was present in six patients (6.0%) in the first evaluation after discharge and in 20 patients (20.4%) in the most recent postoperative control. There were 25 reoperations in 17 patients, of which 15 had to be performed for MV regurgitation and two for MV stenosis. Freedom from reoperation was 91% at 1 year, 79% at 10 years, and 76% at 15 and 20 years. We could not identify a statistically significant risk factor for reoperation. CONCLUSIONS: In patients with AVSD of various morphologies closure of the left AV valve cleft significantly improves outcome without affecting the need for reoperation. Risk factors for early and late death (multivariate analysis) were a pulmonary/aortic pressure ratio >0.7 and the occurrence of any complication after surgery. The concept of an early surgical AVSD correction before an increase in pulmonary vascular resistance and AV valve deformations occur would represent a better surgical option than a late correction as done in our series. Early correction allows for reduction of early mortality, superior long-term survival rates and a high freedom from subsequent valve degeneration.

Optimization of radiographic parameters for paediatric cardiac angiography.

In the paediatric cardiac catheterization laboratory the reduction of the radiation dose of diagnostic and interventional procedures is of high priority. Therefore, we performed an experimental study for optimizing the automatic exposure control (AEC) for cardiac angiography. With a Philips Integris BH 5000 system, six AEC programs were configured to acquire X-ray images of 8 cm to 18.5 cm thick PMMA phantoms at tube voltages between 50 kV and 90 kV, with 0.2 mm or 0.4 mm Cu filters and with or without an anti-scatter grid. At constant detector dose, entrance dose (ED) and image quality were evaluated as functions of the voltage. Changes in image quality were determined by the differential signal-to-noise ratio measured within regions of low (SNRb) and high (SNRd) attenuation. At equal voltages, ED saving was approximately 29% with the 0.4 mm Cu beam filtering as compared with 0.2 mm Cu, largely independent of object thickness. SNRb and SNRd were only dependent on the voltage. While SNRb was high at low voltages, SNRd showed a maximum at approximately 79 kV. Using a grid, ED increased with increasing object thickness by a factor of 1.9 to 3.5. At equal voltages, the grid led to significant image improvements, with SNRb and SNRd increasing by 27% and 11%, respectively. SNRb and SNRd are useful descriptors of the image quality in cardiac angiography. Highest image quality was found with tube voltages between 55 kV and 77 kV, independently of object thickness. To minimize dose, the thickness of the copper filter should be chosen to be as large as possible provided the tube's power limit allows keeping the voltage below the upper limit. In view of the substantial image improvement, the use of a grid is recommended for all patients, even for newborns.

[Erroneous X-ray dose measurements in paediatric cardiac investigations]. / Fehlerhafte Dosismessungen bei kinderkardiologischen Untersuchungen.

According to national and international rules the x-ray exposure of cardiac catheter examinations have to be measured. For a Philips Integris angiographic system used for paediatric heart catheterization we found severe errors in the indicated time of fluoroscopy and total dose area product ( DAP) both for fluoroscopy and radiography. Fluoroscopy times shorter than 6 seconds and DAPs smaller than 0.1 Gy cm (2) are ignored and not considered in the indicated total fluoroscopy time and the fluoroscopic and radiographic DAPs. This error leads to a systematic underestimation of the risk of radiation-induced cancer especially with infants and children.

[Biplane angiographic volumetry of the right and left heart ventricle with optical image pairing]. / Biplane angiographische Volumetrie der rechten und linken Herzkammer mit optimaler Bildpaarung.

Compared to single plane angiographic systems, biplane systems offer the possibility of a merged evaluation of the two x-ray projections. A computer program was developed that allows the assessment of enddiastolic and endsystolic volumes and frame-by-frame analysis of the left and right ventricle based on representing the biplane angiograms as optimal paired images. Optimal pairing means the magnifications are fitted, resulting in identical scales for objects located in the isocenter of the gantry; furthermore the images are rotated such that paired epipolar lines in both planes represent the same cross section of a centered object. The improved border tracing is proved by comparing the vertical extents from the lateral and frontal projection of the right ventricle. The standard deviation of the differences were significantly (p < 0.01) reduced as compared to the generally used unpaired evaluation.