[Early onset pediatric sarcoidosis, diagnostic problems]. / Sarcoïdose à début précoce, difficultés diagnostiques en pédiatrie.

Sarcoidosis, a chronic multisystem inflammatory granulomatous disorder of unknown origin, is a rare disease in children. Two distinct clinical presentations of sarcoidosis in childhood are known. Older children usually show multisystem disease, close to the adult manifestation, with lung infiltration and frequent hilar lymphadenopathy. Prior to the age of 5, sarcoidosis reveals more frequently with the classical triad of rash, arthritis, and uveitis. Due to non-specific clinical features and the lack of a specific test, recognizing sarcoidosis can be difficult in the pediatric population. Moreover, unlike in adults, lung involvement is rare in pediatric sarcoidosis. Given the lack of a definitive blood test, the World Association of Sarcoidosis and Other Granulomatous disorders (WASOG) only recommends dosing the serum angiotensin-converting enzyme (ACE). Its level is usually higher in children than in adults, but an increased ACE may help in the diagnosis. The gold standard is a biopsy specimen with typical epithelioid gigantocellular granuloma without caseating necrosis granuloma, after other disorders known to cause granulomatous disease have been reasonably excluded. We report here the case of a 4.5-year-old male with the history of polyarthritis and uveitis, considered first as juvenile rheumatoid arthritis, followed 5 years later by cutaneous involvement, which led to reconsidering the diagnosis. There were no pulmonary clinical findings. Histology provided the diagnosis of sarcoidosis. He then developed dependence on steroids. The lack of the classical triad delayed the diagnosis several years. This case shows the pediatric singularity of sarcoidosis, which needs to be known so that early and appropriate follow-up can be conducted.

[Leukaemia cutis during acute aleukaemic myeloid leukaemia in a two-month-old infant]. / Leucémie cutanée révélatrice d'une leucémie aiguë myéloïde sans blastes circulants chez un nourrisson de deux mois.

BACKGROUND: Congenital cutaneous leukaemia is rare. PATIENTS AND METHODS: A two-month-old girl presented bluish cutaneous macules of the trunk, histological examination of which suggested acute myeloid leukaemia (LAM B 5). The blood picture was negative for circulating tumour cells and the outcome under chemotherapy was favourable at one year of follow-up. DISCUSSION: The prognosis of congenital leukaemia is serious. Aleukaemic congenital leukaemia is seen occasionally but is rare. The existence of multiple cutaneous tumours in newborn infants raises the possibility of TORCH infection and of other malignant tumours such as nephroblastoma or neuroblastoma.

Numerical simulations of phase contrast velocity mapping of complex flows in an anatomically realistic bypass graft geometry.

Combined in vitro experiments and numerical simulations were performed to study flow artifacts in phase contrast (PC) velocity mapping of steady flow through an anatomically realistic aortocoronary bypass graft model. The geometry was obtained through imaging and computational reconstruction of a left anterior descending (LAD) coronary artery of a porcine heart. Simulated images of through-plane velocity were obtained at selected slices of the geometry. These were then compared and contrasted with velocity images of corresponding sites that were obtained from in vitro experiments. The shift and distortion of the measured velocity profile was well predicted by the simulation, while trajectories obtained from particle tracking were shown to be useful in understanding the origins of the flow artifacts that were observed.

Echo-planar magnetic resonance myocardial perfusion imaging: parametric map analysis and comparison with thallium SPECT.

Magnetic resonance (MR) perfusion FLASH imaging has been used for assessing coronary artery disease (CAD). Echo-planar MR techniques have advantages in speed and in making MR perfusion imaging results more clinically accessible through parametric maps, but have not been previously assessed. We implemented a spin-echo, echo-planar MR technique and applied it at rest and during adenosine stress in 26 patients with CAD and abnormal thallium single-photon-emission computed tomography (SPECT), and analyzed the results by using a newly developed parametric map analysis of time to peak, peak intensity, and slope of contrast washin. The results were compared with the results of conventional visual analysis of the perfusion cine series. For detecting abnormal coronary territories, MR and SPECT were comparable for sensitivity, specificity, and accuracy (thallium, 70%, 78%, and 73%; MR, 79% 83%, and 80%; P = NS). There was good agreement between thallium and MR during stress (kappa = 0.49), but defects were larger by MR (2.4 vs. 3.1 segments for slope; P < 0.01). Additional segments were detected at rest by MR (58 for slope vs. 25 for thallium), which correlated with areas that became abnormal with stress in the thallium (sensitivity, 100%; specificity, 63%). The parametric maps were easier and faster to interpret than review of the original first-pass series of images (chi2 = 10.8; P < 0.04). The diagnostic performance of echo-planar perfusion MR and SPECT was similar, and combining the results with parametric mapping was useful for interpretation and considerably improved data display for clinical interpretation. MR, however, was faster and yielded images of higher resolution with no radiation burden. In multislice mode, these new MR techniques may have clinical value.

Cardiovascular T2-star (T2*) magnetic resonance for the early diagnosis of myocardial iron overload.

AIMS: To develop and validate a non-invasive method for measuring myocardial iron in order to allow diagnosis and treatment before overt cardiomyopathy and failure develops. METHODS AND RESULTS: We have developed a new magnetic resonance T2-star (T2*) technique for the measurement of tissue iron, with validation to chemical estimation of iron in patients undergoing liver biopsy. To assess the clinical value of this technique, we subsequently correlated myocardial iron measured by this T2* technique with ventricular function in 106 patients with thalassaemia major. There was a significant, curvilinear, inverse correlation between iron concentration by biopsy and liver T2* (r=0.93, P<0.0001). Inter-study cardiac reproducibility was 5.0%. As myocardial iron increased, there was a progressive decline in ejection fraction (r=0.61, P<0.001). All patients with ventricular dysfunction had a myocardial T2* of <20 ms. There was no significant correlation between myocardial T2* and the conventional parameters of iron status, serum ferritin and liver iron. Multivariate analysis of clinical parameters to predict the requirement for cardiac medication identified myocardial T2* as the most significant variable (odds ratio 0.79, P<0.002). CONCLUSIONS: Myocardial iron deposition can be reproducibly quantified using myocardial T2* and this is the most significant variable for predicting the need for ventricular dysfunction treatment. Myocardial iron content cannot be predicted from serum ferritin or liver iron, and conventional assessments of cardiac function can only detect those with advanced disease. Early intensification of iron chelation therapy, guided by this technique, should reduce mortality from this reversible cardiomyopathy.

Magnetic resonance velocity vector mapping of blood flow in thoracic aortic aneurysms and grafts.

Magnetic resonance imaging with multidirectional cine velocity mapping was used to study relationships between aortic blood flow patterns and the geometry of thoracic aortic aneurysms and grafts. Ten patients with 13 thoracic aortic aneurysms, single or multiple, or grafts (4) participated in the study. The causes of disease were atherosclerosis (4), Marfan's syndrome (2), trauma (1), and unknown (1), and there were two dissections. Spin-echo imaging and cine velocity mapping in 10 mm thick slices with vertical and horizontal velocity encoding were done. Maps of the two velocity components were processed into multiple computer-generated streaks whose orientation and length corresponded to velocity vectors in the chosen plane. The dynamic arrow maps were compared with previously reported aortic arrow maps from normal subjects. The forward flow occupied the entire lumen in the normal aorta in systole and small vortices were only present in the sinuses of Valsalva. Atherosclerotic aneurysms in the ascending aorta were located at the anterior right and had oblique, eccentric jet flows that created a large secondary vortex in the aneurysm. Patients with Marfan's syndrome had a central jet and two large vortices, one on each side. All other aneurysms, dissections, and grafts had irregular flows and vortices not seen in normal subjects. Magnetic resonance imaging with multidirectional velocity mapping is a powerful noninvasive tool to assess morphologic features and disturbed blood flow in aortic aneurysms and grafts. Recognizably altered flow patterns were found to be associated with altered vessel geometry. The significance of this requires further investigation.

Magnetic resonance imaging of coronary arteries: technique and preliminary results.

BACKGROUND: Coronary artery imaging is an important investigation for the management of coronary artery disease. The only reliable technique presently available, x ray contrast angiography, is invasive and is associated with a small morbidity and mortality. Alternative non-invasive imaging would be useful, but the small calibre and tortuosity of the coronary vessels, and cardiac and respiratory motion create formidable imaging problems. OBJECTIVE: The development of rapid magnetic resonance imaging of the coronary arteries. PATIENTS: 21 healthy controls and five patients with coronary artery disease established by x ray contrast angiography, of whom two had undergone bypass grafting. METHODS: Magnetic resonance imaging was performed with gradient echoes and a segmented k-space technique, such that a complete image was acquired in 16 cardiac cycles during a breathhold. The signal from fat was suppressed and images were acquired in late diastole to reduce artefact from cardiac motion. An imaging strategy was developed for the proximal arteries, including longitudinal imaging from oblique planes defined according to the origins and the continuation of the arteries in the atrioventricular grooves or interventricular sulcus. RESULTS: Of the 26 subjects studied, 22 were imaged successfully. Identification of the artery was possible for the left main stem, left anterior descending, right coronary, and left circumflex arteries respectively in 95%, 91%, 95%, and 76%. The arterial diameter at the origin could be measured in 77%, 77%, 81%, and 63%. The mean (SD) arterial diameter in each case (4.8 (0.8), 3.7 (0.5), 3.9 (0.9), and 2.9 (0.6) mm) was not significantly different from reference values. The mean length of artery visualised was 10.4 (5.2), 46.7 (22.8), 53.7 (27.9), and 26.3 (17.5) mm. In 12 healthy men the total coronary area was 30.9 (9.2) mm2 and the ratio compared with body surface area was 16.4 (4.4) mm2m2 (both p = NS compared with reference values). In seven patients in whom x ray contrast coronary angiography was available, the proximal arterial diameter was 3.9 (1.1) mm measured by magnetic resonance and 3.7 (1.0) mm by x ray contrast angiography (p = NS). The mean difference between the measurements was 0.2 (0.5) mm, and the coefficient of variation was 13.7%. All five occluded coronary arteries were identified, as were all three vein grafts. In two patients insertion of the graft into the native arteries was identified. CONCLUSIONS: Magnetic resonance coronary angiography is feasible. Good results were obtained by a breath-hold, fat suppression technique, gated to late diastole. Arterial occlusions and vein grafts were readily identified. Further studies are required to establish its value in the detection of coronary stenosis and to develop the measurement of coronary flow velocity which could be used to quantify the severity of the stenosis.

Magnetic resonance morphological, chemical shift and flow imaging in peripheral vascular disease.

We have used magnetic resonance imaging to study the aorto-iliac region in 13 patients with peripheral disease. Five healthy volunteers were studied for comparison. Magnetic resonance spin-echo imaging, chemical shift imaging to determine lipid content of atheroma, phase-shift velocity mapping and quantitative flow studies were obtained and the findings compared with radiological angiograms. The velocity profiles study showed an increased velocity at the site of a stenosis in eight patients who had iliac artery disease. Quantitative flow measurements made in both iliac arteries and the aorta in five patients and five volunteers showed a flow ratio in both iliac arteries less than 0.85 in patients with a stenosis of one iliac artery and a ratio greater than 0.85 in the volunteers. In one patient studied before and after angioplasty, flow improved post-angioplasty. The flow curve showed a characteristic distortion in diseased vessels compared with healthy vessels. In the chemical shift images of aortic atheroma five were classified as fibrous and three were lipid rich. This preliminary study showed the potential of magnetic resonance to assess non-invasively the morphology, composition and the haemodynamic significance of atheroma. This could be important in the study of the progression of peripheral vascular disease and its response to pharmacological and surgical intervention and in the planning treatment of lesions.

Magnetic resonance characterization of pulmonary arterial blood flow after single lung transplantation.

Magnetic resonance imaging has been used to study pulmonary arterial anatomy and to measure pulmonary arterial blood flow in patients with single lung transplantation. Nine patients and nine control subjects matched for age and sex were studied. The anatomy of the main pulmonary artery and its main branches, as well as the site of arterial anastomoses, was identified and measurements of their diameters were taken. There were no significant differences in diameters of these vessels between the patients and the control subjects. Arterial blood flows to the transplanted lung were 2.07 +/- 0.45 L/min/m2 in the group with right lung transplantation and 2.43 +/- 0.60 L/min/m2 in those with left lung transplantation compared with 1.22 +/- 0.22 L/min/m2 and 1.27 +/- 0.41 L/min/m2 in the control group, respectively. The ratio of blood flow in the transplanted and the native lungs in all patients studied was 2.8 +/- 0.83:1. The flow profile in the artery of the transplanted lung showed a wide forward flow during systole and most of diastole, whereas that of the native lung showed a narrow early systolic peak and a reverse flow in most of diastole. These differences in the volume and pattern of flow in the transplanted lung are most likely related to the relative resistance in the native and the transplanted lung and could constitute an additional index for monitoring the condition of patients with lung transplantation and help in the understanding of the physiology of the denervated pulmonary vascular bed.

Vena caval flow: assessment with cine MR velocity mapping.

The authors used cine magnetic resonance (MR) velocity mapping to study flow in the superior vena cava (SVC) and inferior vena cava (IVC) of 13 healthy control subjects and 13 patients with right-sided cardiac disease. In the control subjects, peaks of flow in systole and diastole were observed, and mean SVC flow was 35% of the cardiac output. Respiratory gating was used in six control subjects to acquire images at end inspiration and end expiration, and although the systolic peak was reduced at end expiration, total flow was unchanged. A reduced systolic peak and retrograde flow in the IVC were observed in patients with tricuspid regurgitation. A reduced diastolic peak was seen in patients with pulmonary hypertension, pericardial constriction, and right ventricular dysplasia, reflecting reduced diastolic compliance of the right ventricle. In the patient with obstruction of the SVC, absence of flow was confirmed, and retrograde flow was seen in the azygos vein. The authors believe that cine MR velocity mapping is a reliable method of studying vena caval flow noninvasively and that it has important potential applications for the investigation of disorders of the right side of the heart.

[Magnetic resonance tomography flow measurement in cerebral arteriovenous angioma]. / Kernspintomographische Flussmessung bei einem zerebralen arteriovenösen Angiom.

A case of cerebral AVM associated with Klippel-Trenaunay Syndrome is presented where Magnetic Resonance (MRI) flow measurement revealed details of the shunt from the cerebral arterial system. The AVM was supplied by two arteries, the main flow came from the left vertebral and internal carotid artery. The arterial blood supply of the AVM was about 268 ml/min, the av-shunt flow was about 18% of the whole carotid and vertebral upstream flow.

Magnetic resonance imaging of the pulmonary arteries and their systemic connections in pulmonary atresia: comparison with angiographic and surgical findings.

Patients with pulmonary atresia require several investigations and operations. The role of magnetic resonance imaging in assessing the anatomy of the central pulmonary arteries, the origin and course of systemic collateral arteries, and the patency of surgical shunts has been studied with the aim of reducing the need for invasive angiography. Transverse, coronal, and sagittal images were obtained in ten adult patients and assessed without knowledge of surgical and angiographic data. Central pulmonary artery anatomy varied from full development to complete absence. Transverse slices showed hypoplastic arteries particularly well and the findings accorded with surgical and angiographic data in all patients. The origin and proximal course of 15 large collaterals were identified on the magnetic resonance images and 18 were identified by surgical and angiographic data. Magnetic resonance imaging did not show their distal connections; if such information is required angiography will be needed. Five surgical shunts were shown to be patent and two occluded at surgery and angiography, and this was confirmed on the magnetic resonance images. The patency of a further four shunts was uncertain, but they were not seen by magnetic resonance and were presumed to be occluded.

Magnetic resonance velocity mapping: clinical application of a new technique.

Magnetic resonance velocity mapping is a new technique which provides a display of velocity within the cardiovascular system at any point of the cardiac cycle. A short field echo sequence with even echo rephasing is used to obtain a signal from rapidly moving blood and a cine display is provided by rapid repetition of the sequence. The amplitude image shows the anatomy, with blood giving a high signal and areas of turbulent flow no signal. The phase image is a map of velocities at each point in the image plane. Thirteen cases are described in which the technique either provided a diagnosis or helped in functional assessment. Flow through atrial and ventricular septal defects was seen, although turbulent flow distal to the ventricular shunts led to some loss of quantitative information. In three patients with valve disease jets of abnormal flow were seen because of signal loss and it is suggested that the size of the area of turbulence may be used to quantify the severity of regurgitation. Velocities were measured in four coronary artery bypass grafts in two patients, and low velocity was seen in a graft with distal disease that supplied the infarcted territory. Velocity was reduced distal to an aortic coarctation and it was increased at the site of narrowing caused by thrombosis in a deep vein. The speed and direction of flow in the central vessels in a patient with complex congenital heart disease helped to establish the anatomy. The technique provides useful information in a wide range of disorders of the cardiovascular system, and in some cases may avoid the need for invasive investigation.