J.-M. Correas

Ultrasound of renal tumors

Abstract. Despite the limitations of US in providing a complete evaluation of renal tumors before treatment planning, initial screening, characterization of renal masses and staging of RCCs can benefit from some recent advances of the technique. One of the most relevant clinical benefits of US is the increased early detection of RCCs. Recent technical improvement of gray-scale imaging has increased US performance in the detection of small renal tumors. Combined gray-scale and color Doppler US findings may strongly suggest the histopathologic nature of a renal tumor with respect to the size, the US attenuation characteristics, and the vascular distribution of the lesion. Ultrasound contributes additional diagnostic information for differential diagnosis of some renal masses that remain equivocal at CT, including: atypical cystic lesions; solid renal tumors with poor vascularity; and angiomyolipomas with minimal fat component. Ultrasound also may provide additional diagnostic information over CT in selected cases of RCCs with venous invasion. In addition to some diagnostic and therapeutic procedures that can benefit from US guidance, intraoperative US remains the only available tool that enables to ensure renal-parenchymal-sparing surgery.

Recommandations en Onco-Urologie 2010 : Cancer du rein

Il s’agit d’une maladie a transmission autosomique dominante, a forte penetrance (95 % a 60 ans), pour laquelle un seul gene est en cause : le gene VHL situe sur le bras court du chromosome 3 (3p25-p26) (Tableau 1) [1]. La mutation causale du gene VHL est identifiable chez presque tous les patients atteints de cette affection. Il s’agit le plus souvent de mutations ponctuelles (75 % des cas) portant sur la sequence codante, mais des microdeletions, des micro-insertions, des deletions etendues ou une hypermethylation le plus souvent du promoteur ont egalement ete observees. Plus de 150 mutations differentes ont ete repertoriees sur l’ensemble des 3 exons [3-4]. Une consultation d’oncogenetique et un typage genetique du ou des sujets atteints puis des membres de la famille permet la mise en evidence de mutations du gene VHL et l’identification des sujets predisposes a cette maladie (Niveau de preuve 1). Il est recommande de depister les enfants a partir de 5 ans. Une imagerie abdominale annuelle est souhaitable car il existe un risque de 2,7 % de decouverte par an de nouvelle lesion renale (Niveau de preuve 4) [5-6].

Ultrasound elastography of the prostate: State of the art

Prostate cancer is the cancer exhibiting the highest incidence rate and it appears as the second cause of cancer death in men, after lung cancer. Prostate cancer is difficult to detect, and the treatment efficacy remains limited despite the increase use of biological tests (prostate-specific antigen [PSA] dosage), the development of new imaging modalities, and the use of invasive procedures such as biopsy. Ultrasound elastography is a novel imaging technique capable of mapping tissue stiffness of the prostate. It is known that prostatic cancer tissue is often harder than healthy tissue (information used by digital rectal examination [DRE]). Two elastography techniques have been developed based on different principles: first, quasi-static (or strain) technique, and second, shear wave technique. The tissue stiffness information provided by US elastography should improve the detection of prostate cancer and provide guidance for biopsy. Prostate elastography provides high sensitivity for detecting prostate cancer and shows high negative predictive values, ensuring that few cancers will be missed. US elastography should become an additional method of imaging the prostate, complementing the conventional transrectal ultrasound and MRI. This technique requires significant training (especially for quasi-static elastography) to become familiar with acquisition process, acquisition technique, characteristics and limitations, and to achieve correct diagnoses.

Ultrasound elastography: Advantages, limitations and artefacts of the different techniques from a study on a phantom

Ultrasound elastography is a technique currently under development. Its use in clinical practice is complicated because of the wide range of techniques used by the different manufacturers and the parameters proposed to characterise tissues. A comparative analysis on five ultrasound diagnostic systems has been performed on a calibrated elasticity phantom and demonstrated that: (1) all systems tested are reliable for simple qualitative analysis: is a nodule present and is it harder or softer than neighbouring tissues? (2) the deformation or hardness ratios between two regions are usually, however, not proportional to the theoretical ratios and only a binary analysis greater than 1 (harder) and less than 1 (softer) is reliable and could be used as a negative predictive value (NPV) for malignant lesions, as has been suggested by some authors; (3) finally, quantitative analysis using shear wave techniques performed variably, reliable measurements being obtained with only one of the systems. Measurements produced by these different systems must not be compared in clinical practice to monitor a patient and the threshold values proposed in the literature must only be used in an analysis carried out with the same system and same probe.

Elastography of the thyroid

Thyroid nodules are very common, while thyroid cancer is rare and has a very good prognosis. Thyroid nodule ultrasound characterization performed by experienced clinicians allows the selection of the tumours to be punctured and guiding fine needle aspiration (FNA). FNA provide cytology information able to differentiate benign tumours from cancer in approximately 80% of cases. However, it remains difficult to identify thyroid cancers with ultrasound imaging, as demonstrated by the very low rate of cancers detected in all of the carried out FNA (approximately 5%). As a majority of thyroid cancers are hard, the stiffness evaluation has become part of nodular characterization. Since 2005, elastography has been used for the evaluation of thyroid nodules; quasi-static elastography was the first technique available and used, at first, an external pressure induced by the probe, which was then replaced by carotid internal excitation allowing improvement in sensitivity. Semi-quantitative analysis allows comparison of tissue elasticities between tissue with elasticity anomalies and normal tissue and provides therefore useful analytic information. Shear wave elastography (SWE) provides a map of the elasticity in a region and allows stiffness quantification of lesions in kilopascals in order to reinforce the predictive value of malignancy. A tumour whose stiffness is greater than 65kPa or for which the stiffness ratio is greater than 3.7 compared to surrounding healthy tissue is highly suspicious. SWE may enable the detection of malignant follicular tumours that currently escape detection by the ultrasound-guided ultrasound/aspiration cytology couple. Lymph node metastasis of papillary thyroid cancer can also be detected by elastography due to its increased stiffness.

Adénome oncocytaire du rein : redéfinition des critères diagnostiques en tomodensitométrie

Resume Objectif Redefinir et evaluer les criteres diagnostiques tomodensitometriques (TDM) de l’oncocytome renal (OR) dans le but d’elargir les indications de traitement chirurgical conservateur pour une tumeur benigne. Materiel et methode Etude retrospective sur 57 patients porteurs de 69 OR avec correlation anatomo-pathologique. Un test en double aveugle sur 60 tumeurs renales de diametre > 3 cm, comprenant des oncocytomes renaux et des cancers est realise afin d’evaluer l’efficacite de criteres tomodensitometriques redefinis. Resultats Parmi les gros OR (diametre > 3 cm), 55 % ont presente une cicatrice, hypodense a un temps nephrographique tubulaire, centrale ou excentree, associee a un parenchyme peripherique homogene, hypervascularise, et dont la forme a conduit a definir 3 categories distinctes. L’utilisation de nos criteres diagnostiques a donne une concordance inter-observateur satisfaisante (p Conclusion Les criteres tomodensitometriques que nous avons redefinis, eventuellement associes a la biopsie renale, devraient permettre d’augmenter les indications de nephrectomie partielle pour les oncocytomes de grande taille.

Double-echo gradient chemical shift MR imaging fails to differentiate minimal fat renal angiomyolipomas from other homogeneous solid renal tumors.

OBJECTIVES The purpose of this retrospective study was to evaluate the diagnostic performance of double-echo gradient chemical shift (GRE) magnetic resonance (MR) imaging for the differentiation of angiomyolipomas with minimal fat (mfAML) from other homogeneous solid renal tumors. METHODS Between 2005 and 2010 in two institutions, all histologically proven homogenous solid renal tumors imaged with computed tomography and MR imaging, including GRE sequences, have been retrospectively selected. A total of 118 patients (mean age: 61 years; range: 20-87) with 119 tumors were included. Two readers measured independently the signal intensity (SI) on GRE images and calculated SI index (SII) and tumor-to-spleen ratio (TSR) on in-phase and opposed-phase images. Intra- and interreader agreement was obtained. Cut-off values were derived from the receiver operating characteristic (ROC) curve analysis. RESULTS Twelve mfAMLs in 11 patients were identified (mean size: 2.8cm; range: 1.2-3.5), and 107 non-AML tumors (3.2cm; 1-7.8) in 107 patients. The intraobserver reproducibility of SII and TSR was excellent with an intraclass correlation coefficient equal to 0.99 [0.98-0.99]. The coefficient of correlation between the readers was 0.99. The mean values of TSR for mfAMLs and non-mfAMLs were -7.0±22.8 versus -8.2±21.2 for reader 1 and -6.7±22.8 versus -8.4±20.9 for reader 2 respectively. No significant difference was noticed between the two groups for SII (p=0.98) and TSR (p=0.86). Only 1 out of 12 mfAMLs and 11 of 107 non-AML tumors presented with a TSR inferior to -30% (p=0.83). CONCLUSION In a routine practice, GRE sequences cannot be a confident tool to differentiate renal mfAMLs from other homogeneous solid renal tumors.

Recommandations pour l'utilisation des agents de contraste ultrasonores

es agents de contraste echographiques ainsi que les techniques appropriees d’imagerie ultrasonore sont de plus en plus integres a la pratique clinique tant pour l’imagerie diagnostique que pour le suivi therapeutique de lesions de plusieurs organes. Jusqu’a present, il n’existait pas de regles de bonne pratique exposant les principes techniques essentiels, proposant une qualification minimale des investigateurs, decrivant des procedures d’investigation par etapes, seriant les principales indications cliniques et faisant le point sur les considerations de securite. Le besoin de telles recommandations a ete souligne par le Bureau de Delegues de l’EFSUMB (European Federation of the Societies for Ultrasound in Medicine and Biology) lors de sa reunion tenue durant le congres Euroson en mars 2003 a Copenhague. Ces recommandations ont ete discutees et adoptees au cours d’une conference de consensus specifique organisee a Rotterdam en janvier 2004. Ces recommandations s’appuient en premier lieu sur les references bibliographiques disponibles incluant des resultats d’etudes cliniques prospectives. Si aucun resultat significatif n’etait disponible dans la litterature, le comite s’est fonde sur l’expertise de ses membres, sur des rapports ainsi que sur le consensus obtenu durant la conference dans le domaine des ultrasons et de l’echographie de contraste. Ces recommandations ont pour objectif de proposer des protocoles standard pour l’utilisation et l’administration du produit de contraste ultrasonore (PCUS) et d’ameliorer la prise en charge des patients. La premiere version, de janvier 2004, concerne principalement l’evaluation des lesions focales hepatiques (LFH) connues ou suspectees. Ces recommandations donnent des orientations generales pour l’usage de PCUS. Toutefois, les cas individuels doivent etre geres sur la base des donnees cliniques disponibles de facon specifique pour chaque cas. Ces recommandations seront actualisees pour refleter les futures connaissances scientifiques et l’evolution rapide de la technologie ultrasonore.

Conduite à tenir devant un nodule thyroïdien : échographie, cytoponction

All ultrasound examinations for thyroid nodule should include a malignancy risk assessment based on the markedly hypoechoic nature of the nodule, presence of microcalcifications, ill-defined margins, nodule with shape taller than wide and intra-nodular hypervascularity at color Doppler. In patients with multinodular thyroid gland, precise nodule mapping is necessary to allow accurate follow-up of each nodule, correctly identify which nodule(s) is hyper functioning on iodine scan (if done) and guide fine needle aspiration (FNA) of suspicious nodules. As such, all reports of US examinations for thyroid nodule(s) should include a diagram or map of the nodule(s). An evaluation of cervical lymph nodes also helps to determine the malignancy risk. The main US features for malignant adenopathy include: rounded lymph node, loss of normal echogenic fatty hilum, and loss of normal hilar vascularization. Several patterns are highly suggestive of thyroid cancer metastasis: microcalcifications, cystic components, hyperechoic nodes, mimicking thyroid tissue. FNA is a routine procedure in experienced hands. It is the best test to determine which nodule(s) needs to be surgically removed. Thyroglobulin assay on needle-washing fluids after FNA is mandatory when lymph node metastasis is suspected. Preoperative lymph nodes mapping with neck ultrasound is commonly repeated prior to surgery to assess the need for node dissection in patients with proven thyroid malignancy.

Tubulocystic renal cell carcinoma: a new radiological entity

AbstractTubulocystic renal cell carcinoma (TC-RCC) is a recently identified renal malignancy. While approximately 100 cases of TC-RCC have been reported in the pathology literature, imaging features have not yet been clearly described. The purpose of this review is to describe the main radiologic features of this rare sub-type of RCC on ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI), based jointly on the literature and findings from a multi-institutional retrospective HIPAA-compliant review of pathology and imaging databases. Using a combination of sonographic and CT/MRI features, diagnosis of TC-RCC appeared to be strongly suggested in many cases.Key Points• Tubulocystic renal cell carcinoma is a new entity with typical imaging features • Diagnosis of tubulocystic renal cell carcinoma can be suggested preoperatively by imaging • Cystic renal lesions with high echogenicity may correspond to tubulocystic carcinoma