[Magnetic resonance imaging in long-term assessment after surgery for aortic coarctation]

OBJECTIVES

Spin echo or gradient echo magnetic resonance imaging provides enough information to plan patient management and can be completed with the use of three-dimensional magnetic resonance angiography to evaluate the need for reintervention, assess follow-up, or discharge the patient.

PATIENTS AND METHODS

From 1990-2003, we evaluated 101 patients after initial corrective surgery for aortic coarctation at the age of 3.1 +/- 3 years, with subsequent postoperative assessment at 1 year and again 12.4 +/- 4.2 years later. No mortality was registered during the follow-up. Corrective surgery was performed in 32 patients (31.6 %) before the first month of life. All the patients were evaluated with spin-echo and echo gradient and 34 were evaluated with magnetic resonance angiography. The patients were classified into two groups: group A consisted of 68 patients (11 < 1 month old) with no complications. End-to-end anastomosis was performed in 55, the Alvarez technique in five, the Waldhausen technique in six, and conduit in two. Group B consisted of 33 patients complicated with early aortic recoarctation (21 corrected before the age of 1 month). End-to-end anastomosis was performed in 29, the Alvarez technique in two, and grafting in two. During the follow-up, 43 reinterventions were performed. Isthmus diameter/descending aorta diameter at the diaphragmatic level and repaired site diameter/descending aorta diameter at the diaphragmatic level were measured.

RESULTS

Group A: the isthmus diameter/descending aorta diameter at the diaphragmatic level index was 0.92 +/- 0.08 and the repaired site diameter/ descending aorta diameter at diaphragmatic level index was 0.90 +/- 0.05. Twenty-three patients were assessed by means of three-dimensional magnetic resonance angiography, which revealed two late stenosis (one in a 10-year-old patient with an end-to-end anastomosis performed previously, and another in an 18-year-old patient with a proximal and distal obstructed conduit). Group B: the isthmus diameter/descending aorta diameter index was 0.84 +/- 0.1 and the repaired site diameter/ descending aorta diameter index was 0.82 +/- 0.11. Eleven patients were assessed by means of three-dimensional magnetic resonance angiography, which revealed five stenosis indexes (0.53-0.73) surgically corrected before the age of 2 months, four with an initial technique based on end-to-end anastomosis and one with a graft.

CONCLUSIONS

Our results support the influence of young age, the use of end-to-end anastomosis and grafts in recoarctation and their late influence on recurrent recoarctation. The patients in group A were discharged in childhood or adulthood after periodic follow-up every 5 years with magnetic resonance angiography for 18 years with results within the normal range, while patients in group B required longer follow-up.

[Low grade astroblastoma: pathological and magnetic resonance findings]

INTRODUCTION

The astroblastoma is an uncommon type of glial tumour. It accounts for less than 1% of all tumours of the central nervous system. It originates in the tanicytes, ependymal cells present in the embryo and usually seen in adolescents and young adults. Radiologically it presents as a well delimited, heterogeneous tumour with a solid component which takes up contrast and is cystic, giving the same signal as cerebrospinal fluid (CSF). The pathological characteristics are of the formation of radial astroblastic pseudorosettes with perivascular hyalinization.

CASE REPORT

An 18 year old woman presented with a 15 month history of motor deficit of her right limbs with occasional left frontal headache and horizontal diplopia on looking towards the left. On examination there was minimal claudication of the right limbs and bilateral papilloedema. Magnetic resonance showed a very well circumscribed left prefrontal neoplasm of heterogeneous aspect, with areas of solid and cystic appearance in the different sequences. The area of cystic appearance did not show the CSF signal in all sequences of the pulse. The tumour was totally excised. On histological study there were radial astroblastic pseudorosettes with perivascular hyalinization, with two mitoses per 10 fields of great magnification and the final diagnosis was of low grade astroblastoma. The apparently cystic portion was composed of friable gelatinous tissue. Fifteen months after her operation the patient is still asymptomatic.

CONCLUSION

We report the radiological and pathological findings of a low grade astroblastoma.

[Magnetic resonance of congenital cardiopathies]

OBJECTIVE

The objective of this study was to determine the usefulness of magnetic resonance in the diagnosis and follow-up in congenital heart disease.

PATIENTS AND METHODS

Between 1992 and 1994, we have evaluated 250 patients (between 1 day-22 years of age) with congenital heart disease. We used a Philips-Gyroscan 0.5 Tesla set-up and the studies were made with ECG-gated multislice sequences with the time of repetition adapted to the cardiac frequency. The slice thicknesses were 3-10 mm and the field of view was 100-400 mm. Three axes were used: axial, oblique coronal and 30-60 degrees oblique sagittal. Three groups were made: A) Patients in whom MR imaging was the elected technique for establishment of the diagnosis; B) Patients were MR imaging was an alternative technique; and C) Patients were MR imaging was complementary to other techniques. All patients underwent a Doppler echocardiographic study or an angiocardiogram.

RESULTS

Group A) One hundred and fifty-one patients were included with the following conditions: Eighty-two with coarctation of the aorta or aortic arch interruption, 12 with vascular ring, 5 with truncus arteriosus in order to evaluate the pulmonary branches, 28 cases operated for Fallot or transposition of the great vessels for the evaluation of the pulmonary branches, 16 with single ventricle for the evaluation of the bulboventricular foramen, 5 with complex congenital heart disease and 3 with pericardial agenesia-herniation. Group B) Sixty-five patients were included in this group with the following diagnoses: Ten with aorto-pulmonary colateral arteries, 13 with anomalous pulmonary drainage of the systemic veins, 38 with tronco-conal anomalies and 4 with supravalvular aortic stenosis. Group C) Thirty-four patients with the following conditions were included in this group: Ten with common atrioventricular septal defects, 6 with tricuspid atresia, 6 with atrioventricular and ventriculoarterial discordance and 12 with other anomalies.

CONCLUSIONS

MR imaging can replace other techniques in the diagnosis and follow-up of some congenital heart diseases and in a non-invasive way.

[Evaluation of pulmonary arteries using nuclear magnetic resonance in patients with pulmonary atresia]

OBJECTIVES

Patients with pulmonary atresia and a ventricular septal defect have one outlet vessel; the aorta. The pulmonary arteries may be present or absent, and there is a collateral shunt. Magnetic resonance imaging is used to study this.

MATERIAL AND METHODS

We evaluated 10 patients with pulmonary atresia with ventricular septal defect. Five were males and the others were females, ages ranged between 1 day and 25 years, three patients were newborns. We used common planes, but mainly: axial-transverse and coronal, normal and right or left oblique projections.

RESULTS

The size of the ventricular septal defect was 1.75 +/- 0.67 cm (0.5-3.2). The pulmonary trunk was absent in 7 patients, it was atretic in 2 and it was present in one. Confluent pulmonary branches were seen in 6 patients (right 0.58 +/- 0.12, left 0.53 +/- 0.19), not confluent in 2 (with only one branch in each case) and absent in the other two. There was collateral shunt flowing from the descending aorta in 7 patients, from the ascending aorta in two and from the aortic in the final case. The ascending aorta was dilated in all cases (diameter 3.04 +/- 1.39), afterwards the relation between the ascending aorta and the descending aorta was 1.87 +/- 0.25. The aortic arch was right sided in 5 patients.

CONCLUSIONS

Magnetic resonance imaging is an alternative diagnostic method to angiocardiography. It gives complete information about the size, the position and the connection of the pulmonary arteries. It is also useful to evaluate the aortopulmonary to bronchial shunt.

[An imaging and color echo-Doppler study of interventricular defects]

OBJECTIVE

Evaluation of ventricular septal defect with two-dimensional echocardiography and color flow Doppler.

PATIENTS AND METHODS

We had studied by this method 180 patients; 97 males and 83 (mean age 1.5 +/- 1 years) diagnosed of a VSD. Cases with a complex cardiopathy were excluded from the study. The VSD was classified according to its location and relation to the tricuspid anulus and semilunar valves in perimembranous VSD, muscular VSD and subarterial double committed defect. The colour Doppler identified one or two areas of low through the ventricular septum with a zona of proximal acceleration throughout systole. Every group can be evaluated in different views but they all have a selective echocardiographic view except for muscular trabecular VSD.

RESULTS

Seventy-six patients had perimembranous VSD (30 inlet, 26 trabecular and 20 infundibular-outlet), 102 had muscular VSD (3 inlet, 97 trabecular and 2 infundibular-outlet) and 2 had a subarterial double committed defect. A ventricular septal aneurysm was associated in 20 patients with muscular or perimembranous defects. Six patients, 2 of the perimembranous trabecular VSD, 2 muscular-trabecular VSD and 2 subarterial were initially misclassified. In this last 2 cases the turbulence created in the pulmonary valve was wrongly interpreted as pulmonary valvular stenosis; subcostal view for both tracts is necessary to avoid such mistake. In conclusion, color Doppler flow mapping is very useful to differentiate the various types as VSD and aids identification of multiples ventricular septal defects.