[MRI and the thorax]. / IRM et thorax.

In the field of thoracic pathology, the indications for MRI are well established in pleural, mediastinal and vascular disease. Compared to CT, MRI, with its superior contrast resolution, allows better tissue characterization of tumours, as well as an accurate assessment of mediastinal or parietal invasion prior to surgery. MRI is a non-ionizing imaging technique, which can be repeated for the follow-up of aortic diseases such as dissections or aneurysms. Clinicians should be aware of the contraindications to MRI and the adverse effects of gadolinium.

[Chest CT: spectrum of normal findings]. / Les frontières de la normalité en tomodensitométrie thoracique.

A fundamental issue in the interpretation of chest CT lies in the ability to determine normality. Technical advances have resulted in an increasing number of submillimeter sections which in turn has resulted in the identification of a large number of minor abnormalities with no significant pathophysiological consequence. These images should be properly interpreted in order to avoid unnecessary follow-up examinations and radiation exposure. Often they are due to respiratory or cardiac motion artifacts. Others are explained by aging, anatomic variants, physiological phenomenon or tobacco use. These borderline imaging features detected on chest CT are described according to the main anatomical compartments of the thorax: lung and vessels, airways, pleura and chest wall, mediastinum and heart.

Congenital coronary arteries anomalies: review of the literature and multidetector computed tomography (MDCT)-appearance.

The prevalence of coronary arteries congenital anomalies is 1 to 2% in the general population. Although the spectrum of their clinical manifestations is very broad from total inocuity to lethal, anomalies of coronary arteries need to be recognized by clinicians in certain circumstances: they are the first cause of death in young adults under physical exercise and an abnormal course of a coronary artery can complicate a cardiac surgery. Therefore, a non-invasive test is highly suitable for detecting anomalies of coronary arteries and multidetector computed tomography (MDCT) is likely to be the best one. To understand how anomalies of coronary arteries may occur, we have reviewed the recent literature about their development. Then, the main types of anomalies are presented with their clinical context, and representative MDCT images from our personal database are used for illustration.

[Pleural mesothelioma: imaging contribution]. / Le mésothéliome pleural: place de l'imagerie.

Imaging plays an essential role in management of patients of with pleural mesothelioma. In this article, we discuss the respective roles for ultrasonography, computed tomography, magnetic resonance imaging, and positon emission tomography for the diagnosis, staging, and postherapeutic evaluation of pleural mesothelioma.

Measurement of cardiac ventricular volumes using multidetector row computed tomography: comparison of two- and three-dimensional methods.

This study compared a three-dimensional volumetric threshold-based method to a two-dimensional Simpson's rule based short-axis multiplanar method for measuring right (RV) and left ventricular (LV) volumes, stroke volumes, and ejection fraction using electrocardiography-gated multidetector computed tomography (MDCT) data sets. End-diastolic volume (EDV) and end-systolic volume (ESV) of RV and LV were measured independently and blindly by two observers from contrast-enhanced MDCT images using commercial software in 18 patients. For RV and LV the three-dimensionally calculated EDV and ESV values were smaller than those provided by two-dimensional short axis (10%, 5%, 15% and 26% differences respectively). Agreement between the two methods was found for LV (EDV/ESV: r=0.974/0.910, ICC=0.905/0.890) but not for RV (r=0.882/0.930, ICC=0.663/0.544). Measurement errors were significant only for EDV of LV using the two-dimensional method. Similar reproducibility was found for LV measurements, but the three-dimensional method provided greater reproducibility for RV measurements than the two-dimensional. The threshold value supported three-dimensional method provides reproducible cardiac ventricular volume measurements, comparable to those obtained using the short-axis Simpson based method.

Reproducibility of multi-detector spiral computed tomography in detection of sub-segmental acute pulmonary embolism.

The aim of this study was to evaluate the inter-observer and intra-observer agreement of the diagnosis of sub-segmental acute pulmonary embolism (PE) in an inpatient population explored by 16 slice multi-detector spiral computed tomography (MDCT). Four hundred consecutive inpatients were referred for MDCT for the clinical suspicion of acute PE. One hundred and seventy seven (44.2%) had a known cardio-respiratory disease at the time of examination. Inter-observer and intra-observer agreements for the diagnosis of acute PE and of sub-segmental acute PE were assessed blind and independently by three experienced readers and by kappa statistics. Seventy-five patients were diagnosed as having acute PE findings (19.5%), and clots were located exclusively within sub-segmental arteries in nine patients (12%). When clots were limited to sub-segmental or more distal branches of the pulmonary arteries, kappa values were found to be moderate (0.56) to very good (0.85) for the diagnosis of sub-segmental acute PE, whereas for the diagnosis of acute PE in the whole population, kappa values ranged from 0.84 to 0.97. Intra-observer agreement was found to be perfect (kappa=1). MDCT is a reproducible technique for the diagnosis of sub-segmental acute PE as well as for acute PE. In this inpatient population, sub-segmental acute PE was not a rare event.

[Diagnostic and therapeutic value of lymphography in persistent postoperative chylothorax]. / Intérêt diagnostique et thérapeutique de la lymphographie dans un chylothorax postopératoire persistant.

Chylothorax is a rare but generally severe complication of surgery of congenital heart disease. The authors report the clinical history of a young boy with complex congenital heart disease operated on several occasions and who developed severe and recurrent unilateral chylothorac after a bicavo-bipulmonary derivation. Conservative treatment followed by continuous somatostatin infusion was ineffective. Diagnostic Lipiodol lymphography was required before the chylothorax was cured. The authors describe management of this difficult case and discuss the therapeutic possibilities with reference to a brief review of the literature.

[Sarcoidosis and renal insufficiency]. / Sarcoïdose et insuffisance(s) rénale(s).

Renal complications of sarcoidosis are rare but they may lead to renal failure. The two most common mechanisms are interstitial nephritis and acute hypercalcaemic renal failure. We report the case of a woman who presented both of these complications.

MR imaging of myocardial haematoma after blunt chest injury.

Myocardial contusion after a chest trauma is a frequently under-diagnosed injury. We report two cases of myocardial contusion in which MR imaging, thanks to its contrast capability, was able to assess the presence of a haematoma and in one case to demonstrate the recovery of the lesion.

[Thoracic pathology without apparent radiographic sign: re-interpretation basis]. / La pathologie thoracique sans traduction radiographique apparente: base de ré-interprétation.

A chest radiograph may falsely be initially read as being normal or "apparently" normal. The clinical settings where such a false reading may occur are numerous and variable. The most significant situation is the initially missed single pulmonary nodule, with a reported estimated incidence ranging between 30% and 50%. Airway diseases are also typically silent on chest radiographs. The trachea and main bronchi are not well evaluated and some small airways diseases may have very little manifestations, even when advanced. Vascular diseases, when diffuse with bilateral symmetrical hypo- or hyperperfusion, are difficult to detect along with localized but symmetrical vascular disorders and endo- or transthoracic extracardiac shunts. Finally, any disease involving the pleura, pericardium, mediastinum, or lung interstium may be undetectable radiologically at the time of presentation. This paper reviews and illustrates these various diseases and their radiological findings.

Thin-section CT of the lung: influence of 0.5-s gantry rotation and ECG triggering on image quality.

The aim of this study was to determine if ECG triggering and a shorter acquisition time of 0.5-s rotation decrease cardiac motion artifacts of thin-section CT of the lung. In 25 patients referred for thin-section thoracic CT, 1-mm thin-section slices were performed with a scanning time of 0.5 s with ECG gating, 0.5 s and 1 s during the diastolic phase of the heart at five identical anatomical levels from the aortic arch to lung basis. At each anatomical level and for each lung, cardiac motion artifacts were graded independently on a four-point scale by three readers. Patients were divided into two groups according to their heart rate. A four-way analysis of variance was used to assess differences between the three modalities. Mean cardiac motion artifacts scores were rated 1.23+/-0.02, 1.47+/-0.02, and 1.79+/-0.02, at 0.5 s with ECG gating, 0.5 s without ECG gating, and 1 s, respectively (F=139, p<0.0001). At the four anatomical levels below the aortic arch, the left lung scores were greater than the right lung score for the three modalities. For the modality 0.5 s with ECG gating no difference of scores was found between patients grouped according to their cardiac frequency. The 0.5-s gantry rotation with or without ECG gating scans reduces cardiac motion artifacts on pulmonary thin-section CT images and is mainly beneficial for the lower part of the left lung.

[Myocardial infarction in a child with an anomalous left coronary artery arising from the right coronary sinus. Value of echocardiography]. / Infarctus du myocarde chez un enfant et anomalie de naissance du tronc coronaire gauche du sinus coronaire droit. Apport de l'échocardiographie.

An anomalous left coronary artery arising from the right sinus of Valsalva with a trajectory between the aorta and the main pulmonary artery is a rare isolated congenital anomaly carrying a high risk of sudden death and of acute myocardial ischaemia, especially in children and young adults in a context of exercise. It is usually a post-mortem finding. The authors report the rare case of a 12 year old child who suffered acute myocardial infarction on exercise due to this condition. The diagnosis was made in the acute phase by echocardiography. Surgical correction was performed as this is the only means of prevention of sudden death of an ischaemic recurrence. Effort syndromes in children or young adults should lead to a request for echocardiographic examination to exclude the diagnosis in a non-invasive manner as well as those of hypertrophic cardiomyopathy or congenital aortic stenosis.

Feasibility of endocardial edge detection by using an inversion recovery artifact.

An inversion recovery (IR) artifact was used to delineate the blood/wall boundary in left ventricles. The artifact consisted of a hypointensity signal in pixels located at the boundary of two contiguous tissues with different T(1) relaxation times. The feasibility of measuring the ejection fraction using the artifact was tested in ten healthy volunteers, with two IR snapshot-FLASH sequences possessing different times of repetition (TR = 11msec and TR = 3.5msec) and appropriate times of inversion. The comparison with a cine-MRI sequence showed that ejection fraction measurements are feasible when performed with a snapshot-FLASH sequence that has a sufficiently short TR (3.5msec).

[Mediastinal sarcoidosis and vascular thrombosis: a fortuitous association?]. / Sarcoïdose médiastinale et thrombose vasculaire: association fortuite?

A 43-year-old woman presented with a recent history of intermittent dyspnea with wheezing. The chest x-ray evidenced mediastinal nodes. A CT scan showed vascular embolism. Mediastinoscopy was performed and pathology examination of the node confirmed the diagnosis of sarcoidosis. The patient responded to corticosteroid and anticoagulation therapy. Is this a fortuitous association? A vascular localization of sarcoidosis? Thrombosis by compression?

Functional significance of air trapping detected in moderate asthma.

The aim of this study was to evaluate bronchial and lung abnormalities in patients suffering from moderate asthma as defined by international guidelines, with special attention to air trapping on CT in comparison with that detected in smoking and non-smoking normal subjects. Twenty-two patients classified as moderate asthma and control subjects including healthy volunteers, smokers (n = 10) or non-smokers (n = 12) were prospectively explored by high-resolution CT (HRCT) performed at suspended full inspiration and expiration. The same expiratory protocol was performed 15 min after inhalation of 200 microg of salbutamol. Patients underwent pulmonary function tests within the same week and bronchodilator response was assessed following inhalation of salbutamol. Abnormalities of bronchi and lung parenchyma on inspiratory CT and air trapping on expiratory CT, in dependent and non-dependent areas, were assessed and scored semi-quantitatively by two independent observers. Comparison of score mean values between the different groups was performed using Mann-Whitney test and Spearman correlation between CT findings and pulmonary function tests were calculated. Mosaic perfusion was observed in 23% of asthmatics. Air-trapping scores were significantly higher in asthmatic patients than in non-smoking control subjects (p = 0.003), but not than in smokers. This difference was ascribed to non-dependent zones of the lung for which air-trapping scores were also higher in asthmatic patients (p = 0.003) and in smoking subjects (p = 0.004) than in normal controls. In the asthmatic group, a significant positive correlation was found between airways resistance and bronchial dilatation score (p = 0.01), and between small airways obstruction index and mosaic perfusion score (p = 0.05). In addition, both FEV1 and reversibility of small airways obstruction values correlated with air-trapping score (p = 0.03 and p = 0.007, respectively). No change could be detected in air-trapping score following salbutamol inhalation. Patients suffering from moderate asthma present mosaic perfusion and larger areas of air trapping than normal subjects, particularly in non-dependent areas of the lung. These lung abnormalities are related to small airways obstruction.

Percutaneous CT-guided biopsy of the lung: comparison between aspiration and automated cutting needles using a coaxial technique.

PURPOSE: To compare the accuracy and complication rate of two different CT-guided transthoracic needle biopsy techniques: fine needle aspiration and an automated biopsy device. METHODS: Two consecutive series of respectively 125 (group A) and 98 (group B) biopsies performed using 20-22 gauge coaxial fine needle aspiration (group A) and an automated 19.5 gauge coaxial biopsy device (group B) were compared in terms of their accuracy and complication rate. RESULTS: Groups A and B included respectively 100 (80%) and 77 (79%) malignant lesions and 25 (20%) and 18 (21%) benign lesions. No significant difference was found between the two series concerning patients, lesions, and procedural variables. For a diagnosis of malignancy, a statistically significant difference in sensitivity was found (82.7% vs 97.4%) between results obtained with the automated biopsy device and fine needle aspiration respectively. For a diagnosis of malignancy, the false negative rate of the biopsy result was significantly higher (p <0.005) in group A (17%) than in group B (2.6%). For a specific diagnosis of benignity, no statistically significant difference was found between the two groups (44% vs 26%) but the automated biopsy device provided fewer indeterminate cases. There was no difference between the two groups concerning the pneumothorax rate, which was 20% in group A and 15% in group B, or the hemoptysis rate, which was 2.4% in group A and 4% in group B. CONCLUSION: For a diagnosis of malignancy when a cytopathologist is not available on-site, automated biopsy devices provide a lower rate of false negative results and a similar complication rate to fine needle aspiration.

Mediastinal lymphangioma in adults: CT and MR imaging features.

Adult mediastinal lymphangiomas are rare lesions the diagnosis of which is difficult based on imaging studies. A retrospective study of CT, MR, and pathologic findings of mediastinal lymphangioma was performed in order to correlate pathological and imaging findings. Nine cases of adult lymphangiomas were identified in the records of our institution over a 12-year period. The CT, MR, and pathologic findings were reviewed. Lesions were classified pathologically as unilocular, cavernous, and intermediate types. Pathologic examination identified six cases of unilocular lesion, two cases of cavernous type, and one intermediate type. The CT features (n = 9) included a smoothly marginated non-enhancing mass of water attenuation (n = 7), a non-enhancing mass of soft tissue attenuation (n = 1), and an enhancing multiseptated mass (n = 1). Lesions were located in the anterior mediastinum (n = 2), right paratracheal (n = 4), subcarinal (n = 1), aortopulmonic window (n = 1) areas, and below the left hilum extending into the posterior mediastinum (n = 1). The MR features (n = 3) were characterized by an enhancing multicystic and multiseptated appearance, evocative of a cavernous type in two cases. The CT appearance of mediastinal thoracic lymphangioma is variable depending on the pathologic type. The most common unilocular type is a non-enhancing thin-walled mass on CT. A less frequent cavernous type can be suggested based on a multiseptated and loculated mass on CT and/or MR examination.