Marie-Pierre Revel

Diagnostic strategy for patients with suspected pulmonary embolism: a prospective multicentre outcome study

BACKGROUND We designed a prospective multicentre outcome study to evaluate a diagnostic strategy based on clinical probability, spiral CT, and venous compression ultrasonography of the legs in patients with suspected pulmonary embolism (PE). The main aim was to assess the safety of withholding anticoagulant treatment in patients with low or intermediate clinical probability of PE and negative findings on spiral CT and ultrasonography. METHODS 1041 consecutive inpatients and outpatients with suspected PE were included. Patients with negative spiral CT and ultrasonography and clinically assessed as having a low or intermediate clinical probability were left untreated. Those with high clinical probability underwent lung scanning, pulmonary angiography, or both. All patients were followed up for 3 months. FINDINGS PE was diagnosed in 360 (34.6%) patients; 55 had positive ultrasonography despite negative spiral CT. Of 601 patients with negative spiral CT and ultrasonography, 76 were clinically assessed as having a high probability of PE; lung scanning or angiography showed PE in four (5.3% [95% CI 1.5-13.1]). The remaining 525 patients were assessed as having low or intermediate clinical probability, and 507 of them were not treated. Of these patients, nine experienced venous thromboembolism during follow-up (1.8% [0.8-3.3]). The diagnostic strategy proved inconclusive in 95 (9.1%) patients, and pulmonary angiography was done in 74 (7.1%). INTERPRETATION Withholding of anticoagulant therapy is safe when the clinical probability of PE is assessed as low or intermediate and spiral CT and ultrasonography are negative.

Diagnosis of pulmonary embolism by multidetector CT alone or combined with venous ultrasonography of the leg: a randomised non-inferiority trial

BACKGROUND Multislice CT (MSCT) combined with D-dimer measurement can safely exclude pulmonary embolism in patients with a low or intermediate clinical probability of this disease. We compared this combination with a strategy in which both a negative venous ultrasonography of the leg and MSCT were needed to exclude pulmonary embolism. METHODS We included 1819 consecutive outpatients with clinically suspected pulmonary embolism in a multicentre non-inferiority randomised controlled trial comparing two strategies: clinical probability assessment and either D-dimer measurement and MSCT (DD-CT strategy [n=903]) or D-dimer measurement, venous compression ultrasonography of the leg, and MSCT (DD-US-CT strategy [n=916]). Randomisation was by computer-generated blocks with stratification according to centre. Patients with a high clinical probability according to the revised Geneva score and a negative work-up for pulmonary embolism were further investigated in both groups. The primary outcome was the 3-month thromboembolic risk in patients who were left untreated on the basis of the exclusion of pulmonary embolism by diagnostic strategy. Clinicians assessing outcome were blinded to group assignment. Analysis was per protocol. This study is registered with ClinicalTrials.gov, number NCT00117169. FINDINGS The prevalence of pulmonary embolism was 20.6% in both groups (189 cases in DD-US-CT group and 186 in DD-CT group). We analysed 855 patients in the DD-US-CT group and 838 in the DD-CT group per protocol. The 3-month thromboembolic risk was 0.3% (95% CI 0.1-1.1) in the DD-US-CT group and 0.3% (0.1-1.2) in the DD-CT group (difference 0.0% [-0.9 to 0.8]). In the DD-US-CT group, ultrasonography showed a deep-venous thrombosis in 53 (9% [7-12]) of 574 patients, and thus MSCT was not undertaken. INTERPRETATION The strategy combining D-dimer and MSCT is as safe as the strategy using D-dimer followed by venous compression ultrasonography of the leg and MSCT for exclusion of pulmonary embolism. An ultrasound could be of use in patients with a contraindication to CT.

Software Volumetric Evaluation of Doubling Times for Differentiating Benign Versus Malignant Pulmonary Nodules

OBJECTIVE The purpose of our study was to evaluate the reliability of software-calculated doubling times for discerning malignant versus benign nodules. MATERIALS AND METHODS CT lung analysis volumetric software was used to retrospectively calculate the doubling times of 63 solid noncalcified nodules by comparing nodule volumes on baseline and follow-up CT scans obtained a median of 3.7 months apart. A final diagnosis based on validated criteria was available for all 63 nodules. All CT examinations were performed with 1.25-mm-thick slices on a four-detector unit. Taking 500 days as the upper value for malignancies, we evaluated whether the software-calculated doubling times could be used to distinguish malignant from benign solid nodules. We also examined whether the relative volume variation of benign nodules correlated with initial nodule size, interscan interval, or differences in contrast administration or exposure parameters between baseline and follow-up CT. RESULTS There were 52 benign and 11 malignant nodules. Benign nodules had a median doubling time of 947 days and a mean relative volume variation of -4.4% (range, -50% to 38%). Malignant nodules had a median doubling time of 117 days and a mean relative volume variation of 102% (22-462%). The sensitivity, specificity, and negative and positive predictive values of the volumetric software for diagnosing malignancy were 91% (95% confidence interval [CI], 0.59-1.00), 90% (95% CI, 0.79-0.97), 98% (95% CI, 0.89-1.00), and 67% (95% CI, 0.38-0.88), respectively. No correlation was found between the relative volume variation of benign nodules and their initial size, the interscan interval, or differences in contrast administration or exposure parameters between the two CT examinations. CONCLUSION Software-calculated pulmonary nodule doubling times of more than 500 days have a 98% negative predictive value for the diagnosis of solid malignant pulmonary nodules. This method may be useful for diagnosing malignant pulmonary nodules on follow-up CT.

Diagnostic accuracy of magnetic resonance imaging for an acute pulmonary embolism: results of the 'IRM-EP' study.

Summary.  Background:  Magnetic resonance imaging (MRI) has not been validated as an alternative diagnostic test to computed tomography angiography (CTA) in patients with suspicion of a pulmonary embolism (PE).

Thoracic endometriosis syndrome: CT and MRI features

Thoracic endometriosis is considered to be rare, but is the most frequent form of extra-abdominopelvic endometriosis. Thoracic endometriosis syndrome affects women of reproductive age. Diagnosis is mainly based on clinical findings, which can include catamenial pneumothorax and haemothorax, non-catamenial endometriosis-related pneumothorax, catamenial haemoptysis, lung nodules, and isolated catamenial chest pain. Symptoms are typically cyclical and recurrent, with a right-sided predominance. Computed tomography (CT) is the first-line imaging method, but is poorly specific; therefore, its main role is to rule out other pulmonary diseases. However, in women with a typical clinical history, some key CT findings may help to confirm this often under-diagnosed syndrome. MRI can also assist with the diagnosis, by showing signal changes typical of haemorrhage within diaphragmatic or pleural lesions.

Interstitial lung disease in anti-synthetase syndrome: Initial and follow-up CT findings

PURPOSE To describe the initial and follow-up CT features of interstitial lung disease associated with anti-synthetase syndrome (AS-ILD). MATERIALS AND METHODS Two independent thoracic radiologists retrospectively analysed thin-section CT images obtained at diagnosis of AS-ILD in 33 patients (17 positive for anti-Jo1, 13 for anti-PL12, and three for anti-PL7 antibodies). They evaluated the pattern, distribution and extent of the CT abnormalities. They also evaluated the change in findings during follow-up (median 27 months; range 13-167 months) in 26 patients. RESULTS At diagnosis, ground-glass opacities (100%), reticulations (87%) and traction bronchiectasis (76%) were the most common CT findings. Consolidations were present in 45% of patients. A non-specific interstitial pneumonia (NSIP), organizing pneumonia (OP) or mixed NSIP-OP CT pattern were observed in 15 out of 33 (45%), seven out of 33 (21%) and eight out of 33 (24%) patients, respectively, whereas the CT pattern was indeterminate in three patients. During follow-up, consolidations decreased or disappeared in 11 out of 12 patients (92%), among which seven within the first 6 months, but honeycombing progressed or appeared in ten out of 26 patients (38%) and overall disease extent increased in nine out of 26 patients (35%). CONCLUSION CT features at diagnosis of AS-ILD mainly suggest NSIP and OP, isolated or in combination. Consolidations decrease or disappear in most cases but the disease may progress to fibrosis in more than one third of patients.

DIPNECH: when to suggest this diagnosis on CT

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is an under-recognized disease characterized by proliferation of neuroendocrine cells in the bronchial wall. It is considered a pre-invasive lesion for lung carcinoid tumours and is found in 5.4% of patients undergoing surgical resection for lung carcinoid tumours. Other manifestations of DIPNECH include bronchial obstruction and formation of tumorlets. DIPNECH preferentially affects middle-aged women. Patients are either asymptomatic or present with long-standing dyspnoea due to obstructive syndrome that can be mistaken for asthma. At CT, mosaic attenuation with multiple small nodules is very suggestive of DIPNECH. The aim of this review is to describe DIPNECH-related CT features and correlate them with histology, in order to help radiologists suggest this diagnosis and distinguish DIPNECH from other causes of mosaic perfusion.

Avoiding overdiagnosis in lung cancer screening: the volume doubling time strategy

It has been 2 years since the breakthrough publication of the National Lung Cancer Screening Trial (NLST) results, yet there are still unresolved questions about cancer screening. Despite the possibility of reducing lung cancer-related mortality, the risk of detecting indolent lesions that are not life threatening, especially in advanced-age patients, still exists. Another problem is the number of false-positive findings leading to unnecessary diagnostic work-ups. In the NSLT study, for example, 27.2% of computed tomography participants were false positives, leading to follow-up diagnostic procedures in 90% of cases and to surgery in 4.2% [1]. Of course, computed tomography protocols and criteria for screening positivity should ensure accurate detection of all potentially malignant lesions, but this goal alone is not sufficient. Ideally, screening protocols should allow us to detect only true lung cancers, leaving out benign lesions, and among the malignant lesions detected, we should only be identifying those that are sufficiently aggressive to be potentially life threatening. This issue of the European Respiratory Journal includes two articles addressing precisely these problems. The paper by Infante et al. [2] is a review article dedicated to the slow-growing lung cancer entity, whereas the paper from Horeweg et al. [3] gives an overview of the NELSON strategy’s performance, especially its rate of false positives. Infante et al . [2] provide evidence of slow-growing lung cancers by analysing tumour volume doubling times (VDTs) in different lung cancer series. Considering a VDT >400 days to define slow-growing lung cancers, they report a highly variable proportion, ranging from 3% in the International Early Lung Cancer Action Program (I-ELCAP) [4] to 45% in some Japanese series [5]. The authors emphasise that only a minority of baseline VDTs were assessed in I-ELCAP, but …

Computer-aided diagnosis (CAD) of subsolid nodules: Evaluation of a commercial CAD system

OBJECTIVES To evaluate the performance of a commercially available CAD system for automated detection and measurement of subsolid nodules. MATERIALS AND METHODS The CAD system was tested on 50 pure ground-glass and 50 part-solid nodules (median diameter: 17mm) previously found on standard-dose CT scans in 100 different patients. True nodule detection and the total number of CAD marks were evaluated at different sensitivity settings. The influence of nodule and CT acquisition characteristics was analyzed with logistic regression. Software and manually measured diameters were compared with Spearman and Bland-Altman methods. RESULTS With sensitivity adjusted for 3-mm nodule detection, 50/100 (50%) subsolid nodules were detected, at the average cost of 17 CAD marks per CT. These figures were respectively 26/100 (26%) and 2 at the 5-mm setting. At the highest sensitivity setting (2-mm nodule detection), the average number of CAD marks per CT was 41 but the nodule detection rate only increased to 54%. Part-solid nodules were better detected than pure ground glass nodules: 36/50 (72%) versus 14/50 (28%) at the 3-mm setting (p<0.0001), with no influence of the solid component size. Except for the type (i.e. part solid or pure ground glass), no other nodule characteristic influenced the detection rate. High-quality segmentation was obtained for 79 nodules, which for automated measurements correlated well with manual measurements (rho=0.90[0.84-0.93]). All part-solid nodules had software-measured attenuation values above -671Hounsfield units (HU). CONCLUSION The detection rate of subsolid nodules by this CAD system was insufficient, but high-quality segmentation was obtained in 79% of cases, allowing automated measurement of size and attenuation.

Contribution of indirect computed tomographic venography to the diagnosis of postpartum venous thromboembolism.

Summary.  Background: The diagnostic value of indirect computed tomographic venography (CTV), following thoracic computed tomographic angiography (CTA), has not been specifically evaluated in postpartum patients with suspected pulmonary embolism. Objectives: To assess the diagnostic value of CTV in postpartum venous thromboembolism. Methods: We reviewed all CTA and CTV procedures performed during the last 7 years in our institution for suspected pulmonary embolism during the postpartum period. We focused on the quality of CTA, the rates of positive CTA and isolated positive CTV findings, and alternative diagnoses provided by CTV. Results: Fifty‐five CTA and 33 CTV procedures were performed for suspected pulmonary embolism in 47 patients referred between 24 h and 2 months after Cesarean (34 patients) or vaginal (13 patients) delivery. Of the 33 patients who had both CTA and CTV, seven had positive CTA findings and four had isolated positive CTV findings. Thus, the absolute increase in the venous thromboembolism detection rate following CTV was 12.1% [95% confidence interval (CI) 4.0–29.1]. Subcapsular hematoma of the liver or spleen was found on CTV in another two patients without venous thromboembolism. Consequently, CTV had a direct impact on clinical management in six of 33 patients (18%). Conclusion: Our results suggest that postpartum patients with suspected pulmonary embolism have a significant rate of pelvic vein thrombosis and that the use of CTV leads to a 31% relative increase in the detection rate of venous thromboembolism as compared to CTA alone in these patients.