"Triple low" free-breathing CTPA protocol for patients with dyspnoea.

AIM: To assess the performance of a "triple-low" free-breathing protocol for computed tomography pulmonary angiography (CTPA) evaluated on patients with dyspnoea and suspected pulmonary embolism and discuss its application in routine clinical practice for the study of the pulmonary parenchyma and vasculature. MATERIAL AND METHODS: This study was conducted on a selected group of dyspnoeic patients referred for CTPA. The protocol was designed using fast free-breathing acquisition and a small, fixed volume (35 ml) of contrast agent in order to achieve a low-exposure dose. For each examination, radiodensity of the pulmonary trunk and ascending aorta, and the dose-length product (DLP) were recorded. A qualitative analysis was performed of pulmonary arterial enhancement and the pulmonary parenchyma. RESULTS: This study included 134 patients. Contrast enhancement of the pulmonary arteries (409 ± 159 HU) was systematically >250 HU. The duration of acquisition ranged from 0.9 to 1.3 seconds for free-breathing imaging. The mean DLP was in the range of low-dose chest CT acquisitions (145 ± 73 mGy·cm). The analysis was deemed optimal in 90% (120/134) of cases for the pulmonary parenchyma. Sixty-nine per cent (92/134) of cases demonstrated homogeneous enhancement of the pulmonary arteries to the subsegmental level. Only 6% (8/134) of examinations were considered uninterpretable. CONCLUSION: The present "triple-low" CTPA protocol allows convenient analysis of the pulmonary parenchyma and arteries without hindrance by respiratory motion artefacts in dyspnoeic patients.

Kidney cortex segmentation in 2D CT with U-Nets ensemble aggregation.

PURPOSE: This work presents our contribution to one of the data challenges organized by the French Radiology Society during the Journées Francophones de Radiologie. This challenge consisted in segmenting the kidney cortex from coronal computed tomography (CT) images, cropped around the cortex. MATERIALS AND METHODS: We chose to train an ensemble of fully-convolutional networks and to aggregate their prediction at test time to perform the segmentation. An image database was made available in 3 batches. A first training batch of 250 images with segmentation masks was provided by the challenge organizers one month before the conference. An additional training batch of 247 pairs was shared when the conference began. Participants were ranked using a Dice score. RESULTS: The segmentation results of our algorithm match the renal cortex with a good precision. Our strategy yielded a Dice score of 0.867, ranking us first in the data challenge. CONCLUSION: The proposed solution provides robust and accurate automatic segmentations of the renal cortex in CT images although the precision of the provided reference segmentations seemed to set a low upper bound on the numerical performance. However, this process should be applied in 3D to quantify the renal cortex volume, which would require a marked labelling effort to train the networks.

Qualitative and quantitative contrast-enhanced ultrasonography for the characterisation of non-palpable testicular tumours.

AIM: To assess the diagnostic performance of conventional ultrasound (US) and contrast-enhanced ultrasonography (CEUS) in the differential diagnosis of non-palpable intratesticular tumours. MATERIALS AND METHODS: The local ethics review board approved the protocol, and all of the patients provided written informed consent. Between December 2011 and February 2014, men with non-palpable testicular tumours and normal tumour markers who were referred for surgery were included. The tumours were analysed by conventional US, including B-mode and colour Doppler US (CDUS) as well as by CEUS. Morphological aspects and qualitative and quantitative CEUS criteria, based on visual enhancement and time-intensity curves, were assessed for each lesion. RESULTS: Forty patients were ultimately included. Based on histopathological results, the tumours were classified into three groups: benign tumours (n=16), malignant tumours (n=15), and burned-out tumours (n=9). In B-mode, the morphological aspects were significantly different between benign and malignant tumours (p-values from 0.0002 to 0.008). Qualitative and quantitative analyses of the CEUS images revealed that burned-out tumours exhibited significantly less enhancement than malignant and benign tumours: in burned-out tumours, time-intensity curves were flat, whereas in both benign and malignant tumours the curves had a bell-shaped pattern. All intensity parameters were lower for burned-out tumours compared to benign and malignant tumours (p-value from 0.0001 to 0.026). Both benign and malignant tumours enhanced strongly, however, and no significant difference between the two was noted (p-value from 0.0721 to 0.0953). CONCLUSION: Unlike conventional US, which enable benign lesions to be differentiated from malignant or burned-out tumours, CEUS failed to enabled differentiation between benign lesions and malignant vascularised testicular tumours. CEUS appears to have the potential, however, to differentiate burned-out tumours from vascularised testicular tumours.

[One day diagnosis for breast lesions: Medical and psychological assessment--EVADIASEIN study]. / Diagnostic en un jour des lésions du sein: évaluation médicale et psychologique de la prise en charge--étude EVADIASEIN.

INTRODUCTION: Breast cancer is the most frequent feminine cancer in France and its incidence increases steadily. The time of access to medical care is an indicator of the quality of the treatments recommended by the Plan Cancer 2009-2013, as it influences the diagnosis and reduces psychological morbidity during the pre-diagnosis phase. The one-day diagnosis is a recently initiated concept, which offers to get the results of the biopsy on the day it is performed and facilitates the setting-up of therapeutic care with the surgeon met during the one-day medical consultations. The aim of this study is to evaluate the satisfaction of patients who benefited from a one-day breast lesion diagnosis, as well as confirm the decrease of time of access to medical treatment. METHODS: This is an observational, non-interventional and single-centre study based on 27 patients who benefited from one-day breast lesions diagnosis over two years. The patients were only included who had a classified lesion ACR 4 or 5 and visible in the ultrasound. We analyzed the histological concordance between the biopsy and the definitive histology, the time of access to medical care, and the therapeutic treatments We analyzed the psychological impact of such an organization by sending to the patients a questionnaire including the Psychological Consequence Questionnaire (PCQ) and the Breast Cancer Anxiety Indicator (BCA) allowing to estimate the anxiety generated by the pre-diagnostic phase, the DC-Sat allowing to estimate the satisfaction of the consultation of announcement, as well as the same day diagnosis benefit. RESULTS: The patients were 59.8 years old in average [33-87]. The average time between the date of the mammography and the one-day diagnosis consultation (including the biopsy) was 15.0 days [0-60]. Fifty-seven percent of the patients considered this time as short. The average time between the biopsy date and the start of the treatment was 15.9 days [4-30]. The one-day diagnosis took an average of 1.6 days [1-5]. The results of the PCQ showed an important emotional impact during the diagnosis phase, and the average BCA score reached an average of 3.9 on a scale of 5. However, the patients were very satisfied with the diagnosis consultation with an average of 8.7 on a scale of 10, and 95% think the one-day diagnosis is beneficial to the patients. DISCUSSION: This study shows that the one-day breast-damage diagnosis enables to improve the time of access to care, and meets the current recommendations. Even though faster access to treatment does not reduce the psychological morbidity of awaiting diagnosis, the patients express their satisfaction and find the rapidity of the pre-diagnosis phase beneficial. CONCLUSION: In view of this study, the one-day breast-damage diagnosis appears to be a quality feature in the process of access to care and treatment of the patients.

Imaging in upper urinary tract infections.

Most infections of the upper urinary tract are straightforward and do not require any emergency radiological investigations. A sonogram carried out within 48 hours will in most cases be sufficient to eliminate obstructed pyelonephritis requiring emergency drainage of urine. In complicated cases, or those affecting already weakened areas, an urgent CT scan is necessary, preferably after injection of iodinated contrast medium if renal function permits. CT scanning is far better at diagnosis than sonography as well as at investigating whether there are complications. Furthermore, it is essential that the radiologist is aware of unusual and rare forms of pyelonephritis, especially pseudotumoural forms, so that clinicians can be pointed towards the appropriate treatment, avoiding unnecessary and invasive interventions.

Imaging tumours of the penis.

Malignant primary epithelial tumours of the penis are rare and mainly affect uncircumcised men in their fifties to seventies. They are most frequently located in the glans and foreskin. Imaging is performed if the clinician has doubts about deep extension, after a diagnostic biopsy. High-resolution ultrasound and above all MRI are used to detect invasion of the corpora cavernosa and spongiosum. The lesion is often seen as a moderate T2 hyposignal, making it possible to distinguish it from the relative hypersignal of the corpora cavernosa. The sentinel lymph nodes are inguinal. Adenopathy is frequently present, but does not, however, necessarily reflect tumour invasion, as secondary infection of the lesion, which is often ulcerated, is common. The prognosis for T1 N0 tumours is good, at the cost of mutilating ablation. Extension to the lymph nodes is detrimental. Non-epithelial tumours and metastases are even rarer.

[Renal failure: diagnostic work-up]. / Insuffisance rénale: stratégie diagnostique.

The purpose of this article is to review the diagnostic work-up of renal failure, acute or chronic. The role of the radiologist is to exclude the presence of a curable etiology such as urinary tract obstruction or vascular thrombosis. Renal ultrasound with Doppler imaging is the imaging modality of choice for this indication, and the use of a contrast agent is useful to evaluate renal perfusion. Non-contrast CT remains valuable for the diagnosis of some urinary tract pathologies. Finally, MRI is the most comprehensive imaging modality for the evaluation of the urinary tract, but performed as a second line modality mainly for practical reasons but also due to the non-negligible risk of nephrogenic systemic fibrosis secondary to the intravenous administration of gadolinium based contrast agent.

[MRI and staging evaluation of prostate cancer]. / IRM et bilan d'extension du cancer de la prostate.

MRI can assess local and locoregional spread of a newly diagnosed prostate cancer by detecting extracapsular extension (ECE), seminal vesicle invasion (SVI) and lymph node invasion. Endorectal MRI remains the only accurate means to assess local extension. Pelvic MRI with surface coils and the use of superparamagnetic particules provide the sensitivity and the specificity which have never been obtained by the sole measurement of node size of the lymphatic chains draining the prostate gland. With the endorectal coil, only direct signs of extracapsular extension have been maintained and indirect signs have been discarded, giving their too low specificity. Early SVI can only be consistently detected if result of TRUS guided biopsies show involvement of the prostate base. With the pelvic phased array coil, superparamagnetic particules show that metastatic lymph nodes have a specific MR signal which can be detected in normal size nodes. Indications of imaging relies on results of parametrers available before MR imaging. More important than PSA level and Gleason score on biopsies is the so called quantitative histology, represented by the number of sextants involved by tumor and the amount of cancer (measured in mm of tumor) present on biopsies which determine a risk of extraprostatic spread. Of the risk of extraprostatic spread depends indication of MR, which is most probably unnecessary in patients at low risk (<20%) of extraprostatic extension.

Currently used non-specific extracellular MR contrast media.

Magnetic resonance contrast agents have demonstrated their clinical usefulness in a variety of organs for improved detection of various neoplastic, inflammatory and functional abnormalities. Gadolinium chelates are the most widely used. They are extracellular, non-specific contrast agents. Their use in many clinical indications is justified because, in conjunction with improved imaging techniques, these safe and image-enhancing contrast agents add morphologic and functional information compared with unenhanced MR images. This article describes the commercially available compounds, and summarizes their approval status on the international market regarding indications and doses. Their mechanisms of action, biodistributions, toxicities and tolerance profiles in normal and high-risk patient populations are described. Additionally, this article reviews the specific recommendations by the manufacturers for patients at risk. Finally, their main clinical applications are reviewed.

Evaluation of retroperitoneal and pelvic lymph node metastases with MRI and MR lymphangiography.

Local, regional lymph node involvement is an essential prognostic factor and an important determinant of treatment choices for patients with retroperitoneal and pelvic cancer. Current cross-sectional imaging modalities, including computed tomography and magnetic resonance (MR) imaging, use the nonspecific criterion of size and are limited in their ability to differentiate benign from malignant lymph nodes. MR lymphography is a promising imaging modality in differentiating benign from metastatic lymph nodes and provides information on lymph node morphology and function. Ultrasmall superparamagnetic iron oxide (USPIO) particles with a long plasma circulation time are suitable as an MR contrast agent for intravenous MR lymphography. They are taken up by macrophages in normally functioning nodes and reduce the signal intensity of tissue in which they accumulate because of T2 and susceptibility effects of iron oxide. In metastatic nodes, macrophages are replaced by cancer cells, which lack reticuloendothelial activity and cannot take up USPIO. The main mechanisms that might explain a heterogeneous node appearance after USPIO injection are discussed. In published reports, USPIO has shown high degrees of sensitivity and specificity for characterizing lymph nodes in cancer patients. We review the development of USPIO compounds, their imaging characteristics, and our clinical experience.

Contrast medium extravasation injury: guidelines for prevention and management.

Extravasation of contrast material is a well-recognized complication of contrast-enhanced imaging studies. The management of this complication is contentious; therefore, the Contrast Media Safety Committee of The European Society of Urogenital Radiology decided to review the literature and issue guidelines. A comprehensive literature search was carried out. The resulting report was discussed at the 8th European Symposium on Urogenital Radiology in Genoa, Italy. Automated power injection may result in extravasation of large volumes and may or can lead to severe tissue damage. Infants, young children and unconscious and debilitated patients are particularly at risk of extravasation during contrast media injection. Fortunately, most extravasations result in minimal swelling or erythema, with no long-term sequelae; however, severe skin necrosis and ulceration may occur. Large volumes of high osmolar contrast media are known to induce significant tissue damage. Compartment syndrome may be seen associated with extravasation of large volumes. Conservative management is often adequate, but in serious cases the advice of a plastic surgeon is recommended. Based on the review simple guidelines for prophylaxis and management of contrast medium extravasation injuries are proposed.

Iron oxide-enhanced MR lymphography: initial experience.

The detection of nodal metastases is of utmost importance in oncologic imaging. Ultrasmall superparamagnetic iron oxide particles (USPIO) are novel contrast agents specifically developed for MR lymphography. After intravenous administration, they are taken up by the macrophages of the lymph nodes, where they accumulate. They reduce the signal intensity (SI) of normally functioning nodes on postcontrast T2-and T2*-weighted images through the magnetic susceptibility effects on iron oxide. Metastatic nodes, in which macrophages are replaced by tumor cells, show no significant change in SI on postcontrast T2-and T2*-weighted images. Early clinical experience suggests that USPIO-enhanced MR lymphography improves the sensitivity and specificity for the detection of nodal metastases. It also suggests that micrometastases could be detected in normal-sized nodes. This article reviews the physiochemical properties of USPIO contrast agents, their enhancement patterns, and early clinical experience.