Sven Laurin

Collateral flow in coarctation of the aorta with magnetic resonance velocity mapping: Correlation to morphological imaging of collateral vessels

To correlate quantification of collateral flow in aortic coarctation with the morphological visualization of the collateral vessels and to compare different approaches to measurement of collateral flow.

Intralobar bronchopulmonary sequestration in the newborn – a congenital malformation

Background. Intralobar sequestration (ILS) has been suggested to be an acquired lesion. However, we have observed several young infants who had ILS. Objectives. Since this fact seems to indicate a congenital origin, we reviewed our experience. Material and methods. A retrospective review of bronchopulmonary sequestration from the Departments of Radiology and Pathology in Lund between 1964 and 1997. Results. We identified seven infants or young children with a diagnosis of intralobar sequestration. In each patient, the ILS was present before recurrent infection developed. Five had chest X-rays as neonates, one at 3 months and one at 11 months of age. All but one showed an abnormality on their first chest X-ray, consistent with sequestration. Six of the ILS were verified at angiography; all seven were surgically removed. Two of the children with ILS also had congenital cystic adenomatoid malformation (CCAM). Three children had both ILS and scimitar syndrome. Conclusions. The fact that ILS was present in seven newborn and young infants indicates that this lesion is, at least in some patients, a congenital malformation.

PRE-OPERATIVE EVALUATION WITH MR IN TETRALOGY OF FALLOT AND PULMONARY ATRESIA WITH VENTRICULAR SEPTAL DEFECT

Purpose: To assess whether MR imaging could replace angiography in pre-operative evaluation of patients with tetralogy of Fallot and pulmonary atresia with ventricular septal defect (VSD), especially since the surgical correction was done earlier than was previously the rule. Material and Methods: Fourteen patients with tetralogy of Fallot (n=10) or pulmonary atresia with VSD (n=4), mean age 7.5±4.4 months, were evaluated with angiocardiography and MR before definitive surgical correction. Results: There was good diagnostic agreement between the two modalities when evaluating right ventricular outflow obstruction; 86% for valvular and 93% for supravalvular stenosis, but the agreement was somewhat lower for the subvalvular obstruction (57%). Surgery findings, however, were in favour of MR in 5 patients concerning the subvalvular right ventricular outflow tract obstruction. MR images identified all stenoses in the right and left pulmonary arteries, but overlooked one stenosis in the main pulmonary artery. MR could evaluate patency in all palliative shunts. Conclusion: Even in this young age group, MR imaging offers a good alternative to angiocardiography for the pre-operative evaluation of the right ventricular outflow tract, the main pulmonary artery and the proximal right and left pulmonary arteries, before definitive surgical correction of tetralogy of Fallot and pulmonary atresia with VSD.

Cross-sectional echocardiographic measurements of right ventricular size and growth in patients with pulmonary atresia and intact ventricular septum

SummaryFifteen patients with pulmonary atresia or critical pulmonary stenosis and intact ventricular septum were studied. All were operated on in the neonatal period, with valvotomy or a systemic to pulmonary arterial shunt, or both. In 12 patients, right ventricular to pulmonary arterial communication was established in the neonatal period. In three patients, only systemic to pulmonary arterial shunts were constructed. Six patients died. The median follow-up period for the surviving patients was 65 months (range, 12–87 months).Right and left atrial and ventricular dimensions and areas, the tricuspid annular diameter, and the cross-sectional area of the aortic root were measured in cross-sectional echocardiograms from the neonatal period, at the age of 1 year, and at the latest clinical follow-up. A classification of right ventricular morphology was made, based on identification of the inlet, the trabecular, and the outlet parts.Most of the patients had hypoplastic right ventricles at birth but at the latest follow-up, seven of nine surviving patients had right ventricles in the normal range. Right ventricular growth was better in patients who were given a right ventricular to pulmonary arterial communication in the neonatal period and those with complete right ventricular anatomy. The patients who died had severely hypoplastic right ventricles and small tricuspid valves.

CONTRAST‐ENHANCED THORACIC 3D‐MR ANGIOGRAPHY IN INFANTS AND CHILDREN

PURPOSE To optimise breath-hold contrast-enhanced MR angiography (MRA) in infants and children with suspected congenital heart or thoracic vessel malformation. MATERIAL AND METHODS Thirty-nine children (median age 1 year) were examined, using five different ultrafast MRA sequences with a TR between 3.2 and 5.0 ms and the contrast agent meglumine gadoterate. A test injection was used to determine contrast travel time. Different parameters for contrast injection were evaluated. Signal-to-noise ratio (SNR) measurements were performed and image quality and injection timing were evaluated. RESULTS MRA was successful in all patients and image quality was considered very good in 52%. Adequate SNR was achieved with no significant differences between the MR sequences. SNR decreased only 25-30% between subsequent scans. The mean contrast dose was 0.23 mmol/kg. The mean scan time was 12.5 +/- 3.8 s; the shorter scan times made dynamic examinations possible with high temporal resolution. Highest spatial resolution was obtained with TR 4.6/5.0 sequences. CONCLUSION A contrast dose of 0.2 mmol/kg b.w. is recommended with an injection rate of 0.5 to 1.2 ml/s, depending on patient size and scan time. The scan delay time should equal the contrast travel time for optimal vessel enhancement. In the future, contrast-enhanced MRA may be a potential alternative to angiocardiography in infants and children.

Functional evaluation of extracardiac ventriculopulmonary conduits and of the right ventricle with magnetic resonance imaging and velocity mapping

Extracardiac ventriculopulmonary conduits tend to deteriorate over time, developing both obstruction and regurgitation. In this prospective study, magnetic resonance imaging (MRI) was compared with Doppler echocardiography to determine whether MRI improves the noninvasive evaluation of conduit patients. Twenty-five patients (median age 10 years, range 2.5 to 32) were investigated 27 times with Doppler echocardiography and an MRI protocol with spin echo sequences for morphology, velocity mapping, and multislice gradient echo technique for right ventricular volume measuring. Cardiac catheterization data were available in 6 patients. Echocardiography could assess the morphology of the conduits in 6 patients, whereas MRI demonstrated all conduits efficiently. Doppler echocardiography could evaluate the occurrence of regurgitation in 18 patients and could quantify peak velocity in 20 of the patients. A technically adequate MRI velocity mapping was obtained in 25 patients. There was good agreement between MRI and Doppler echocardiography in establishing or not establishing regurgitation, but Doppler echocardiography was less reliable in evaluating the degree of regurgitation. The correlation between peak velocity determined with Doppler and magnetic resonance imaging was r = 0.63 [corrected]. Correlations between catheterization pressure gradients and noninvasive techniques were r = 0.97 for magnetic resonance imaging [corrected] versus catheterization, and r = 0.86 [corrected] for Doppler versus catheterization. MRI can provide complete information on the morphology and function of extracardiac ventriculopulmonary conduits, as well as of the right ventricle. If the results of MRI and echocardiography with Doppler are in agreement, heart catheterization and angiography can be avoided, even in patients considered for conduit replacement.

Pulmonary Artery Sling: Diagnosis by Magnetic Resonance Imaging

Aberrant left-sided pulmonary artery (pulmonary sling) is an uncommon anomaly, which may cause significant respiratory morbidity. The condition should be considered on finding a mass interposed between the trachea and the esophagus on the esophagogram, but diagnosis is usually made with invasive methods. Magnetic resonance imaging (MRI) has been reported as an excellent method for diagnosing cardiovascular anomalies but the findings at MRI in cases of pulmonary artery sling have not been reported previously. In this communication the use of MRI is described for demonstration of pulmonary sling in three patients.

Comparison of a Vasoconstrictor and a Vasodilator in Pharmacoangiography of Bone and Soft-Tissue Tumors

The pharmacoangiographic effect of a vasoconstrictor (angiotensin) and a vasodilator (tolazoline) was compared in 18 patients with bone and soft-tissue tumors. Angiotensin was found to be the drug of choice in increasing diagnostic information on angiography. Ten to 15 mug of angiotensin seems to be a convenient dose in the axillary, iliac, and femoral arteries.

Plasma neutrophil lipocalin, elastase-alpha1-antitrypsin complex and neutrophil protease 4 in preterm infants with respiratory distress syndrome.

Respiratory distress syndrome (RDS) and chronic lung disease of prematurity (CLD) are associated with inflammation of the airways and interstitial tissue of the lung. It is hypothesized that RDS severity and the risk of developing CLD may be correlated with neutrophil gelatinase‐associated lipocalin (NGAL), a marker of leucocyte activity, human elastase‐α1‐antitrypsin complex (HEAT) or free and complexed neutrophil protease 4 (NP4), markers of proteolytic enzyme secretion from granulocytes. Thirty‐three preterm infants with RDS were enrolled in the study and plasma sampled between 3 and 14 days of life. NGAL, HEAT and NP4 concentrations varied widely in infants with RDS. Significant correlations between subsequent development of CLD and plasma concentrations of HEAT and NP4, respectively, were found on days 3–4 of life, p=0.006 and p=0.02, respectively.

Tracheobronchial aspirate fluid neutrophil lipocalin, elastase- and neutrophil protease-4-alpha1-antitrypsin complexes, protease inhibitors and free proteolytic activity in respiratory distress syndrome.

UNLABELLED This study aimed to determine whether the protease/protease inhibitor balance and neutrophil activity is of pathophysiological importance in the severity and resolution of respiratory distress syndrome (RDS) and the eventual development of neonatal chronic lung disease (CLD). Ventilated preterm infants with RDS (n = 43) were studied during their first week of life. Tracheobronchial aspirate fluid (TAF) concentrations of neutrophil lipocalin, the elastase- and neutrophil protease-4 (NP4) complex concentrations, and alpha1-antitrypsin (alpha1AT), antichymotrypsin (ACT) and secretory leucocyte protease inhibitor (SLPI) levels were analysed. Free proteolytic and elastolytic activities were also determined. CLD correlated with low alpha1AT (p = 0.02) and ACT (p = 0.02) levels at 3-4 d of age and low SLPI (p = 0.03) at 7-8 d of age. No correlations were found between CLD or severity of RDS (as judged from radiological examination) and neutrophil lipocalin, elastase- and NP4-alpha1AT complexes during the first week of life, with one exception: RDS X-ray severity and the elastase-alpha1AT complex concentration were correlated at 3-4d of age (p = 0.02). Free proteolytic activity occurred in the TAF of 7/30 infants tested on day 3-4 and free elastolytic activity in 1 patient. During the rest of the first week of life no free elastolytic or proteolytic activities were observed. Caesarean section was correlated with low levels of SLPI on day 3-4 (p = 0.01), NP4 (p = 0.03) and ACT (p = 0.05) on day 5-6. Gestational age was positively correlated with protease inhibitors and their complexes at 3-4 d of age. CONCLUSION Free proteolytic or elastolytic activity in the TAF of RDS infants in the first week of life occurred by way of exception. Elastase-/NP4-alpha1AT complex or neutrophil lipocalin levels were not correlated with the development of CLD. The correlation between CLD and low alpha1AT or ACT at 3-4 d and SLPI at 7-8 d of age may be due to either immaturity or complex formation. The severity of RDS as judged from radiological examination was correlated with elastase-alpha1AT complex on day 3-4. The main hypothesis, that TAF protease/protease inhibitor levels or imbalance and leucocyte activity are important factors indicating a high risk of severe RDS and subsequent CLD development, was principally not confirmed.