[Evaluation of cardiac MRI in the follow up assessment of patients with pulmonary arterial hypertension]. / Évaluation de l'IRM cardiaque dans le suivi des patients ayant une hypertension artérielle pulmonaire (EVITA). IRM cardiaque dans le suivi de l'hypertension artérielle pulmonaire.

Haemodynamic follow up in pulmonary arterial hypertension (PAH) is currently based on right heart catheterisation (RHC). The primary objective of the EVITA study is to compare the use of cardiac magnetic resonance imaging (cMRI) with RHC in the identification of an unfavourable hemodynamic status. The secondary objectives are to determine the role of cMRI in the follow up process. Patients will undergo at diagnosis and at follow up visits both RHC and cMRI. Patients will be followed and treated according to the current guidelines. The primary endpoint will be an unfavourable haemodynamic status defined by cardiac index<2.5L/min/m2 or a right atrial pressure≥8mm Hg measured with RHC compared with a cardiac index<2.5L/min/m2 or right ventricle ejection fraction<35% or an absolute decrease of 10% from the previous measurement with cMRI. Exact values of sensitivity, specificity and 95% confidence intervals will be computed. A population of 180 subjects will have a power of 90% with an α risk of 5%. Univariate and multivariate Cox analysis will allow answering to the secondary objectives. We expect to demonstrate that cMRI could be partly used instead of RHC in the follow up of patients with PAH.

Influence of Thoracic Aortic Inflammation and Calcifications on Arterial Stiffness and Cardiac Function in Older Subjects.

BACKGROUND: Vascular aging is accompanied by gradual remodeling affecting both arterial and cardiac structure and mechanical properties. Hypertension is suggested to exert pro-inflammatory actions enhancing arterial stiffness. OBJECTIVE: To determine the influence of thoracic aortic inflammation and calcifications on arterial stiffness and cardiac function in hypertensive and normotensive older subjects. DESIGN: A prospective study. SETTING: An acute geriatrics ward of the University Hospital of Nancy in France. SUBJECTS: Thirty individuals ≥ 65 years were examined, including 15 hypertensive subjects and 15 controls well-matched for age and sex. MEASUREMENTS: Applanation tonometry was used to measure aortic pulse wave velocity (AoPWV) and carotid/brachial pulse pressure amplification (PPA). Left ventricular parameters were measured with magnetic resonance imaging. Local thoracic aortic inflammation and calcification were measured by 18 F-fluorodeoxyglucose positron emission tomography/computed tomography imaging. Biomarkers of low-grade inflammation were also quantified. RESULTS: AoPWV was higher in elderly hypertensive subjects comparatively to normotensive controls (15.5±5.3 vs. 11.9±2.5, p=0.046), and hypertensives had a higher calcification volume. In the overall population, calcifications of the thoracic descending aorta and inflammation of the ascending aorta accounted for respectively 18.1% (p=0.01) and 9.6% (p=0.07) of AoPWV variation. Individuals with high levels of calcifications and/or inflammation had higher AoPWV (p=0.003). Inflammation had a negative effect on PPA explaining 13.8% of its variation (p<0.05). CONCLUSION: This study highlights the importance of local ascending aortic inflammation as a potential major actor in the determination of PPA while calcifications and hypertension are more linked to AoPWV. Assessment of PPA in the very elderly could provide complementary information to improve diagnostic and therapeutic strategies targeting ascending aortic inflammation.

Analysis of the relationship between interictal electrical source imaging and PET hypometabolism.

The aim of this paper is to compare interictal EEG source localizations with statistical analysis of hypometabolisms in PET brain imaging. Both methods are currently used in the pre-surgical evaluation of drug-resistant partial epilepsy, but the relationship between electrical source localizations and hypometabolic areas has not been well defined yet. At the present time, these two methods have been performed on five patients in order to develop a comparative quantitative study with these first results which should be then extended to a larger patient database.

[Cardiac MRI: technical considerations]. / Les conditions techniques d'utilisation de l'IRM cardiaque.

Establishing a clinical cardiovascular magnetic resonance imaging (MRI) program needs a dedicated technical surroundings as well as a specific and expert staff. These guidelines based either on proofs or on expert consensus are stated in order to help the physicians to reach or maintain the competence required for clinical use of cardiovascular MRI. After the general safety statements, the guidelines are focused on hardware and software requirements, the MRI sequences and views, the post-acquisition analysis, and the staff. Specific safety concerns are then approached, more particularly stress testing MRI.

Combined SEEG and source localisation study of temporal lobe schizencephaly and polymicrogyria.

OBJECTIVES: Type 1 schizencephaly (SZ) is a cerebral malformation characterised by a cleft lined and surrounded by a polymicrogyric cortex, extending from the pial region to the peri-ventricular heterotopia. Our purpose was to combine and compare dipole source imaging technique and Stereo-EEG (SEEG) technique in determining the irritative and epileptogenic zones in a case of type 1 schizencephaly. METHODS: High-resolution (64-channel) video-EEG with electrical source imaging and SEEG recordings were performed during a pre-surgical evaluation for medically intractable epilepsy. RESULTS: Anatomo-electro-clinical correlations based on SEEG and source localisation identified two irritative and epileptogenic zones partially overlapping the polymicrogyric cortex surrounding the SZ: an anterior medio-lateral network primarily involving dysplasic limbic structures and a lateral network involving the anterior and middle part of the cleft and polymicrogyric cortex. The most posterior part (at the temporo-parieto-occipital junction) displayed a normal background activity. CONCLUSIONS: Both epileptogenic and electrophysiologically normal cortices coexisted within the same widespread malformation: only the anterior part belonged to the anterior medio-lateral epileptogenic network defined by the SEEG. SIGNIFICANCE: In cases of widespread cortical malformation such as SZ, source localization techniques can help to define the irritative zone and relevant targets for SEEG.

A decision support system improves the interpretation of myocardial perfusion imaging.

PURPOSE: The aim of this study was to investigate the influence of a computer-based decision support system (DSS) on performance and inter-observer variability of interpretations regarding ischaemia and infarction in myocardial perfusion scintigraphy (MPS). METHODS: Seven physicians independently interpreted 97 MPS studies, first without and then with the advice of a DSS. Four physicians had long experience and three had limited experience in the interpretation of MPS. Each study was interpreted regarding myocardial ischaemia and infarction in five myocardial regions. The patients had undergone a gated MPS using a 2-day stress/gated rest (99m)Tc sestamibi protocol. The gold standard used was the interpretations made by one experienced nuclear medicine specialist on the basis of all available clinical and image information. RESULTS: The sensitivity for ischaemia of the seven readers increased from 81% without the DSS to 86% with the DSS (p = 0.01). The increase in sensitivity was higher for the three inexperienced physicians (9%) than for the four experienced physicians (2%). There was no significant change in specificity between the interpretations. The interpretations of ischaemia made with the advice of the DSS showed less inter-observer variability than those made without advice. CONCLUSION: This study shows that a DSS can improve performance and reduces the inter-observer variability of interpretations in myocardial perfusion imaging. Both experienced and, especially, inexperienced physicians can improve their interpretation with the advice from such a system.

[Association of Wolff-Parkinson-White syndrome with isolated non-compaction of the left ventricle: a case report]. / Association du syndrome de Wolff-Parkinson-White a une non-compaction isolée du ventricule gauche. A propos d'un cas.

The Wolff-Parkinson-White syndrome (WPW) may be associated with a number of cardiac pathologies, especially congenital disease, in 7.5 to 17% of cases. The authors report a rare association of the WPW syndrome with two Kent bundles, right and left septal, with non-compaction of the left ventricle in a 52 year old man. This was a chance finding during systematic echocardiography after ablation, and confirmed by cardiac MRI. The patient was asymptomatic.

EANM/ESC procedural guidelines for myocardial perfusion imaging in nuclear cardiology.

The European procedural guidelines for radionuclide imaging of myocardial perfusion and viability are presented in 13 sections covering patient information, radiopharmaceuticals, injected activities and dosimetry, stress tests, imaging protocols and acquisition, quality control and reconstruction methods, gated studies and attenuation-scatter compensation, data analysis, reports and image display, and positron emission tomography. If the specific recommendations given could not be based on evidence from original, scientific studies, we tried to express this state-of-art. The guidelines are designed to assist in the practice of performing, interpreting and reporting myocardial perfusion SPET. The guidelines do not discuss clinical indications, benefits or drawbacks of radionuclide myocardial imaging compared to non-nuclear techniques, nor do they cover cost benefit or cost effectiveness.

[The best of nuclear cardiology and MRI in 2002]. / L'essentiel de 2002 en cardiologie nucléaire et IRM.

In Nuclear Cardiology, the year 2002 was marked by a great number of studies on the gated-SPECT, which allows joint analysis of left ventricle perfusion and contraction. Even if conventional perfusion tomoscintigraphy confirms its foreground role, notably for prognostic evaluation, the value of the gated-SPECT is particularly significant in all areas of its use: coronary heart disease screening, prognosis evaluation, and myocardial viability assessment. Cavitary tomoscintigraphy allows direct evaluation of the ejection fraction and volumes in both ventricles. This innovative technique has been the subject of a great deal of methodological validation work, and will very likely replace traditional isotopic angiography in the future. At last, the value of MIBG scintigraphy for prognostic evaluation, of cardiac insufficiency has been defined, as has its significance for providing evidence of the effect of betablockers on pre-synaptic sympathetic innervation. The year 2002 has also been very fertile for technological innovations, methodological work, and in clinical studies concerning cardiac MRI. In particular, the significance of MRI for evaluating myocardial viability and the transmural extension of necrosis is now well established. Similarly, MRI is becoming an inescapable element in the assessment of congenital cardiopathy. However, its diffusion on a wider scale will only be possible if there is direct collaboration between cardiologists and radiologists.

Effect of exercise on lung-perfusion scanning in patients with bronchogenic carcinoma.

The aim of this study was to determine whether perfusion-scintillation scanning, used as a predictive pre-operative index of lung functionality in patients with lung cancer, is affected by the level of pulmonary blood flow (PBF). Twenty patients with primary lung cancer underwent spirometry and a radionuclide-perfusion scan (macroaggregated albumin particles labelled with 99mTechnetium) both at rest and during the last minute of a ramp-like increase in work rate until exhaustion. On average, the perfusion of the lung with the tumour was significantly reduced by the same magnitude at rest and during exercise (mean+/-SD: -9+/-6% versus -10+/-4% of the cardiac output), regardless of the extent of the tumour. However, subject-by-subject analysis revealed that in two patients, a larger decrease in the perfusion of the lung with the tumour was observed during exercise than at rest (-11% and -17%, respectively). This leads to an underestimation of predictive postoperative functional parameters if resting values are used in these patients. The use of perfusion scintigraphy at rest therefore gives a clear picture of the functionality of the lung before resection in most patients requiring surgery.

[The best of 2001. Nuclear cardiology and MRI]. / L'essentiel de 2001 en cardiologie nucléaire et IRM.

The year 2001 has been very fertile for innovations and developments in the field of cardiac imaging. In Nuclear Cardiology, this year has been marked above all by a very large number of studies on the gated-SPECT, which allows joint analysis of the perfusion and contraction of the left ventricle. The contribution of this technique is recognised as being very significant in all fields using conventional tomoscintigraphy (screening for cardiac disease, evaluations of prognosis and viability,...). Innovation has also been focused in the field of radio-tracers, with studies on the very promising markers of apoptosis or cellular hypoxia. Lastly, much work has been conducted on the gamma-camera, especially to adapt it for imaging with the tracers used in positron emission tomography (PET). This will enable the distribution to all the Nuclear Medicine services of FDG imaging, which is the reference technique for studying myocardial viability. In MRI much work has been carried out on sequences using gadolinium, a vascular contrast agent, in order to identify and localise the sequelae of infarction, even when they are limited to the sub-endocardium. The most spectacular technical innovations were probably in the methods allowing an increase of the recorded signal (SENSE) and in updating the imaging sequences in real time, without apnoea and without ECG synchronisation. But, as every year, significant progress has also been made in MRI angiography of the coronary vessels, and thus in the analysis of myocardial tissue perfusion, with sequences which can be used without the injection of contrast medium.

Detection and prediction of acute heart transplant rejection with the myocardial T2 determination provided by a black-blood magnetic resonance imaging sequence.

OBJECTIVES: This study aimed to determine whether the myocardial T2 relaxation time, determined using a black-blood magnetic resonance imaging (MRI) sequence, could predict acute heart transplant rejection. BACKGROUND: The use of black-blood MRI sequences allows suppression of the confusing influence of blood signal when myocardial T2 is calculated to detect myocardial edema. METHODS: A total of 123 investigations, including cardiac MRI and myocardial biopsy, were performed 8 +/- 11 months after heart transplantation. Myocardial T2 was determined using an original inversion-recovery/spin-echo sequence. RESULTS: A higher than normal T2 (> or = 56 ms) allowed an accurate detection of the moderate acute rejections evidenced at baseline biopsy (> or = International Society for Heart and Lung Transplantation grade 2): sensitivity, 89% and specificity, 70% (p < 0.0001). T2 was increased in grade 2 (n = 11) compared with grade 0 (n = 49, p < 0.05), grade 1A (n = 34, p < 0.05) and grade 1B (n = 21, p < 0.05); T2 was further increased in grade 3 (n = 8) compared with grade 2 (p < 0.05). In addition, in patients without rejection equal to or greater than grade 2 at baseline, a T2 higher than normal (> or = 56 ms) was correlated with the subsequent occurrence of equal or greater than grade 2 rejection within the next three months: sensitivity 63% (12/19) and specificity 78% (64/82) (p = 0.001). CONCLUSIONS: Myocardial T2 determined using a black-blood MRI sequence, is sufficiently sensitive to identify most of the moderate acute rejections documented with biopsy at the same time, but is also a predictor of the subsequent occurrence of such biopsy-defined rejections.

Measurement of blood volume after haemodilution with haemoglobin-based oxygen carriers by a radiolabelled-albumin method.

Recent studies have shown that the use of haemoglobin-based oxygen-carrying solutions (HBOCs) for perioperative haemodilution could significantly reduce the need for packed red blood cells in clinical practice. Though the effects of HBOCs on plasma volume have been characterized in experimental models of volume resuscitation from hypovolaemic shock, little is known about their action in normovolaemic haemodilution conditions. We therefore applied a radiolabelled serumalbumin method to determine blood volume after haemodilution with crosslinked or conjugated haemoglobin, in comparison with a reference solution of hydroxyethyl starch (HES). Three groups of New Zealand white rabbits were studied (n = 7 each group) subjected to moderate exchange transfusion with low molecular weight HES, bis(3,5-dibromosalicyl)fumarate crosslinked haemoglobin (alphaalpha-Hb), or dextran-conjugated haemoglobin (Hb-Dex-BTC). HES induced no changes in heart rate and blood pressure. The amplitude and duration of blood pressure increase and bradycardia were similar in both haemoglobin groups. A significant contraction of blood volume (12%) was observed 60 min after haemodilution with alphaalpha-Hb, compared to HES and Hb-Dex-BTC. At the same time point, a decrease in absolute haemoglobin (plasma haemoglobin x plasma volume) was also noted. This study suggests that in haemodilution conditions, the specific oncotic properties and circulating persistence of crosslinked and conjugated haemoglobin solutions affect the pattern of blood volume distribution differently.

A comparison of the overall first-pass kinetics of thallium-201 and technetium-99m MIBI in normoxic and low-flow ischaemic myocardium.

The specific impact of ischaemia on the myocardial kinetics of thallium-201 and technetium-99m 2-methoxy-2-isobutylisonitrile (MIBI) remains a matter of debate. Using an isolated heart model perfused with red blood cell-enhanced perfusate, we compared the overall first-pass kinetics of 201Tl and MIBI under haemodynamically stable conditions of low-flow ischaemia (> 50% reduction in normal coronary flow and a > or = 20 mmHg fall in systolic contraction pressure, n = 10) and normoxia (n = 11). For both 201Tl and MIBI, we found that under ischaemic conditions (as compared with normoxia) there was a higher initial net extraction fraction (201Tl: 0.78 +/- 0.03 vs 0.72 +/- 0.06, P = 0.006; MIBI: 0.49 +/- 0.10 vs 0.39 +/- 0.11, P = 0.03), a lower clearance rate in the 30 min following extraction (% decrease in cardiac uptake: 201Tl: 30 +/- 12 vs 47 +/- 14, P = 0.02; MIBI: 5 +/- 5 vs 13 +/- 11, P = 0.02) and a higher retention fraction at 30 min (20lTl: 0.54 +/- 0.10 vs 0.39 +/- 0.12, P = 0.004; MIBI: 0.46 +/- 0.08 vs 0.33 +/- 0.12, P = 0.01). Multivariate analyses, however, revealed that all myocardial kinetic parameters of both tracers were dependent only on coronary flow rates, without any additional significant impact of the presence of ischaemia or states of contractility or oxidative metabolism. We conclude that the myocardial fractional retention of both 201Tl and MIBI is strongly correlated with the decrease in coronary flow during ischaemia. This inverse relationship with coronary flow derives from both the flow-dependent increase in the initial myocardial extraction and the decrease in the subsequent myocardial washout of the tracers.

Dipyridamole and exercise SPET provide different estimates of myocardial ischaemic areas: role of the severity of coronary stenoses and of the increase in heart rate during exercise.

In patients unable to perform a maximal exercise test, dipyridamole single-photon emission tomography (SPET) has a higher capacity than exercise SPET to detect coronary artery disease (CAD). However, in patients with myocardial ischaemia who are able to perform a maximal exercise test, it is not known whether these two tests may be equally used to assess the areas of myocardial ischaemia. This study was aimed at comparing the results provided by dipyridamole and exercise SPET in CAD patients with documented exercise myocardial ischaemia. Forty CAD patients who had undergone exercise thallium-201 SPET and who had myocardial ischaemia documented by an unequivocally positive exercise test underwent an additional 201Tl SPET study after dipyridamole infusion and low-level (40 W) exercise. The extent of defects was compared between the two tests and predictors of discrepant results were sought among data from exercise testing and coronary angiography. The extent of SPET defects was equivalent between the two tests in only 11 patients (28%), larger defects being observed with exercise in 18 [average difference: 12%+/-5% of left ventricle (LV)] and with dipyridamole in 11 (average difference: 15%+/-11% of LV). The best independent predictors of discrepancies between the two tests were: (1) increase in heart rate at exercise SPET, with defects being smaller at exercise than after dipyridamole in none of the patients with an increase >60 bpm (0/14), but in 42% of the others (11/26; P=0.004); and (2) an ischaemic territory related to a <70% coronary stenosis, for which SPET defects were always induced at exercise (10/10) but in only 30% (3/10) with dipyridamole (P=0.0004). Exercise and dipyridamole SPET provide different estimates of myocardial ischaemic areas. Dipyridamole allows the unmasking of perfusion abnormalities in patients who have low increases in heart rate at exercise SPET. However, dipyridamole is also much less efficient at inducing perfusion abnormalities in the ischaemic areas supplied by coronary stenoses of intermediate severity at rest angiography.