Jean-Michel Correas

EFSUMB Guidelines and Recommendations on the Clinical Use of Ultrasound Elastography. Part 2: Clinical Applications

The clinical part of these Guidelines and Recommendations produced under the auspices of the European Federation of Societies for Ultrasound in Medicine and Biology EFSUMB assesses the clinically used applications of all forms of elastography, stressing the evidence from meta-analyses and giving practical advice for their uses and interpretation. Diffuse liver disease forms the largest section, reflecting the wide experience with transient and shear wave elastography . Then follow the breast, thyroid, gastro-intestinal tract, endoscopic elastography, the prostate and the musculo-skeletal system using strain and shear wave elastography as appropriate. The document is intended to form a reference and to guide clinical users in a practical way.

Ultrasound contrast agents: properties, principles of action, tolerance, and artifacts

Abstract. The concept of contrast imaging was introduced to ultrasound almost 30xa0years ago. The development of ultrasound contrast agents (USCAs), initially slowed by technical limitations, has become more dynamic during the past decade. The ideal USCA should be non-toxic, injectable intravenously, capable of crossing the pulmonary capillary bed after a peripheral injection, and stable enough to achieve enhancement for the duration of the examination. While satisfying cost–benefit requirements, it should provide not only Doppler but also gray-scale enhancement. Already, Doppler examinations are improved by using USCAs when studying deep and small vessels, vessels with low or slow flow, or vessels with a non-optimal insonation angle. Ultrasound contrast agents also enhance detection of flow within abnormal vessels, including tumor vascularization and stenotic vessels, and provide better delineation of ischemic areas. Research is focusing on the development of specific contrast imaging sequences that allow detection of tissue enhancement similar to that obtained with CT or MRI. These sequences take advantage of the non-linear behavior of the microbubbles within the ultrasound field, bringing real-time perfusion imaging for liver, kidney, and the myocardium into reach. New objectives include targeted agents that could further widen USCA applications to specific delivery of active drugs such as anticoagulants or cytotoxic compounds. The combination of new generations of USCAs and new ultrasound image sequences appears to be very promising and currently represents a significant part of ultrasound research.

Infusion versus bolus of an ultrasound contrast agent: in vivo dose-response measurements of BR1.

RATIONALE AND OBJECTIVESnTo determine the efficacy of an ultrasound contrast agent infusion using Doppler intensitometry estimation of backscatter enhancement in blood.nnnMETHODSnMultiple intravenous injections of BR1 (SonoVue) were performed in chronic dog studies, using bolus (0.05-2 mL) and infusion (3-40 mL/h during 6 minutes) administration. The pulsed Doppler signal from the femoral artery was recorded and analyzed for mean Doppler power and integrated fractional enhancement.nnnRESULTSnFor bolus injection, time-intensity curves exhibited a rapid first pass (peak 30 dB for 0.45 mL) followed by a slower washout. Integrated fractional enhancement exhibited a linear relation with the dose (R2 = 0.99). For infusion administration, peak enhancement increased with the infusion rate from 8 to 22 dB. At rates exceeding 30 mL/h, the enhancement was stable with a plateau-like pattern.nnnCONCLUSIONSnInfusion of BR1 is easily achieved and allows the duration of enhancement to be increased as long as desired. Stable enhancement is obtained for rates greater than 30 mL/h.

Prostate Cancer: Diagnostic Performance of Real-time Shear-Wave Elastography

PURPOSEnTo prospectively evaluate the performance of real-time ultrasonographic (US) shear-wave elastography (SWE) in the diagnosis of peripheral zone prostate cancer in patients with high and/or increasing prostate-specific antigen levels and/or abnormal digital rectal examination results.nnnMATERIALS AND METHODSnAfter signing an informed consent form, men referred for transrectal prostate biopsy were enrolled in this prospective HIPAA-compliant two-center study, which was conducted with institutional review board approval. Transrectal US SWE of the prostate was performed after a conventional transrectal US examination and immediately before US-guided 12-core sextant biopsy. For each sextant, the maximum SWE value was measured and matched to the pathologic results of that sextant biopsy. The diagnostic performance of SWE was assessed at both patient and sextant levels. The elasticity value maximizing the Youden index was used to derive sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).nnnRESULTSnThe elasticity values were matched to pathologic results for a total of 1040 peripheral zone sextants in 184 men. One hundred twenty-nine positive biopsy findings (size, ≥3 mm; Gleason score, ≥6) were identified in 68 patients. The sextant-level sensitivity, specificity, PPV, NPV, and area under the receiver operating characteristic curve for SWE with a cutoff of 35 kPa for differentiating benign from malignant lesions were 96% (95% confidence interval [CI]: 95%, 97%), 85% (95% CI: 83%, 87%), 48% (95% CI: 46%, 50%), 99% (95% CI: 98%, 100%), and 95% (95% CI: 93%, 97%), respectively.nnnCONCLUSIONnUse of a 35-kPa threshold at SWE may provide additional information for the detection and biopsy guidance of prostate cancer, enabling a substantial reduction in the number of biopsies while ensuring that few peripheral zone adenocarcinomas are missed.

Radiofrequency ablation of renal tumours: diagnostic accuracy of contrast-enhanced ultrasound for early detection of residual tumour

ObjectiveTo evaluate the diagnostic accuracy of contrast-enhanced ultrasound (CEUS) in the early detection of residual tumour after radiofrequency ablation (RFA) of renal tumours.MethodsPatients referred to our institution for RFA of renal tumours prospectively underwent CEUS and computed tomography (CT) or magnetic resonance imaging (MRI) before, within 1xa0day and 6xa0weeks after treatment. Identification of residual tumour was assessed by three blinded radiologists. Reference standard was CT/MRI performed at least 1xa0year after RFA.ResultsA total of 66 renal tumours in 43 patients (median age 62xa0years; range 44–71.5) were studied. Inter-reader agreement (κ value) was 0.84 for CEUS. Prevalence of residual disease was 19%. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV), respectively, were as follows: 64% [confidence interval (CI) 39–84], 98% [CI 91–100], 82% [CI 52–95] and 92% [CI 83–97] on 24-h CEUS; 79% [CI 52–92], 100% [CI 94–100], 100% [CI 74–100] and 95% [CI 87–100] on 6-week CEUS; 79% [CI 52–92], 95% [CI 86–98], 79% [CI 52–92] and 95% [CI 86–98] on 24-h CT/MRI; and 100% [CI 72–100], 98% [CI 90–100], 91% [CI 62–98] and 100% [CI 93–100] on 6-week CT/MRI.ConclusionCEUS has high specificity for the early diagnosis of residual tumour after renal RFA.

HUMAN PHARMACOKINETICS OF A PERFLUOROCARBON ULTRASOUND CONTRAST AGENT EVALUATED WITH GAS CHROMATOGRAPHY

The purpose of this study was to prospectively study the human pharmacokinetics of an ultrasound (US) contrast agent through its active ingredient, dodecafluoropentane (DDFP). Expired air and blood samples were collected from 24 volunteers after IV administration from 0.01 to 0.1 mL/kg. They were analyzed by a gas chromatographic method specially adapted to the study of DDFP. Blood data fitted to an open one-compartment model. Elimination half-life range was 1.8 to 2.5 min. The area under the curve was correlated to the dose (r(2) = 0.99). Mean blood clearance ranged from 30 to 49 mL/min kg. Blood apparent distribution volume ranged from 0.09 to 0.15 L/kg. In expired air, DDFP concentration exhibited a biexponential decay. The percentage of recovery was 98 +/- 19% at 2 h. No extraneous peaks were observed, indicating no detectable DDFP metabolites. It was concluded that DDFP pharmacokinetics in blood fitted to an open one-compartment model with a fast elimination half-life. Recovery in expired air was almost complete 2 h after administration.

Recommandations en onco- urologie 2013 du CCAFU : Cancer du rein

Resume Introduction L’objectif de ce travail a ete d’etablir par le sous-comite rein du CCAFU des recommandations pour le diagnostic, le bilan, les traitements et la prise en charge des tumeurs du rein. Methodes Le sous-comite a remis a jour les recommandations de 2010 en s’appuyant sur une revue exhaustive de la litterature effectuee sur PubMed, en evaluant les references et leur niveau de preuve. Resultats Le scanner renal multiphasique est le standard diagnostique pour les tumeurs renales. Les biopsies renales sont d’importance croissante dans la mesure ou elles peuvent modifier la prise en charge. La nephrectomie partielle est a envisager systematiquement pour les tumeurs cT1. La voie incisionnelle reste le standard pour les cancers du rein localement avances. Le traitement des cancers du rein metastatiques inclut de nouvelles drogues. Le role de la nephrectomie en situation metastatique reste a demontrer dans le cadre de l’essai Carmena. Conclusions Les therapies mini-invasives et conservatrices prennent une part croissante dans les cancers du rein localises. L’arsenal therapeutique continue a s’enrichir pour les formes metastatiques.

EFSUMB Guidelines on Interventional Ultrasound (INVUS), Part III – Abdominal Treatment Procedures (Short Version)

The third part of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) Guidelines on Interventional Ultrasound assesses the evidence for ultrasound-guided and assisted interventions in abdominal treatment procedures. Recommendations for clinical practice are presented covering indications, contraindications, safety and efficacy of the broad variety of these techniques. In particular, drainage of abscesses and fluid collections, interventional tumor ablation techniques, interventional treatment of symptomatic cysts and echinococcosis, percutaneous transhepatic cholangiography and drainage, percutaneous gastrostomy, urinary bladder drainage, and nephrostomy are addressed (short version; a long version is published online).

De Novo Renal Tumors Arising in Kidney Transplants: Midterm Outcome after Percutaneous Thermal Ablation

PURPOSEnTo retrospectively evaluate the midterm outcome of patients treated for primary renal cell carcinomas arising in kidney transplants with minimally invasive techniques.nnnMATERIALS AND METHODSnThe institutional review board of each participating institution approved this retrospective study and waived informed consent. This study was HIPAA compliant. A request for cases through the European Society of Urogenital Radiology network was made to institutions for patients who fit the requirements outlined by the authors, and a prospective follow-up of recipients was performed. Twenty-four tumors were identified that developed in the renal allograft of 20 patients from 11 institutions who were treated with radiofrequency ablation (n = 19) or cryoablation (n = 5) between 2003 and 2010. Maximal diameter of masses was 6-40 mm (median, 19.5 mm). Twenty masses were solid, and four were type 4 cystic masses. Preablation biopsy was performed for solid tumors only. All images and biologic and biopsy reports were retrospectively reviewed. Significant differences were determined by using a paired t test before and after ablation.nnnRESULTSnMean follow-up was 27.9 months (range, 7-71 months). Histopathologic examination revealed papillary carcinoma in 17 patients and clear cell carcinoma in three. Tumors were successfully treated with ultrasonographic guidance in six patients, with computed tomographic guidance in 10 patients, and with both in four patients. One case of infection of the tumor site and one case of transitory genitofemoral nerve injury were the only reported complications. No significant change of renal function was noted. Subsequent imaging follow-up did not reveal any case of recurrence in the ablative site.nnnCONCLUSIONnPercutaneous thermal ablation of renal tumors occurring in renal grafts is effective, with low morbidity. .

Feasibility and Diagnostic Accuracy of Supersonic Shear-Wave Elastography for the Assessment of Liver Stiffness and Liver Fibrosis in Children: A Pilot Study of 96 Patients

PURPOSEnTo evaluate the feasibility of using supersonic shear-wave elastography (SSWE) in children and normal values of liver stiffness with the use of control patients of different ages (from neonates to teenagers) and the diagnostic accuracy of supersonic shear wave elastography for assessing liver fibrosis by using the histologic scoring system as the reference method in patients with liver disease, with a special concern for early stages of fibrosis.nnnMATERIALS AND METHODSnThe institutional review board approved this prospective study. Informed consent was obtained from parents and children older than 7 years. First, 51 healthy children (from neonate to 15 years) were analyzed as the control group, and univariate and multivariate comparisons were performed to study the effect of age, transducer, breathing condition, probe, and position on elasticity values. Next, 45 children (from 1 month to 17.2 years old) who underwent liver biopsy were analyzed. SSWE measurements were obtained in the same region of the liver as the biopsy specimens. Biopsy specimens were reviewed in a blinded manner by a pathologist with the use of METAVIR criteria. The areas under the receiver operating characteristics curve (AUCs) were calculated for patients with fibrosis stage F0 versus those with stage F1-F2, F2 or higher, F3 or higher, and F4 or higher.nnnRESULTSnA successful rate of SSWE measurement was 100% in 96 patients, including neonates. Liver stiffness values were significantly higher when an SC6-1 probe (Aixplorer; SuperSonic Imagine SA, Aix-enProvence, France) was used than when an SL15-4 probe (Aixplorer) was used (mean ± standard deviation, 6.94 kPa ± 1.42 vs 5.96 kPa ± 1.31; P = .006). There was no influence of sex, the location of measurement, or respiratory status on liver elasticity values (P = .41-.93), although the power to detect such a difference was low. According to the degree of liver fibrosis at liver biopsy, 88.5%-96.8% of patients were correctly classified, with AUCs of 0.90-0.98 (95% confidence interval [CI]: 0.8, 1.0). The AUC for patients with stage F0 versus stage F1-F2 was 0.93 (95% CI: 0.87, 0.99).nnnCONCLUSIONnSSWE allows accurate assessment of liver fibrosis, even in children with early stage (F1-F2) disease, and the choice of transducer influences liver stiffness values.