Olivier Hélénon

How to characterise a solid renal mass: A new classification proposal for a simplified approach

The reference method for characterising a solid renal mass is computed tomography. MRI and ultrasound can provide useful diagnostic information for characterising masses the cystic or solid nature of which it is not possible to determine from data from the CT scan. For characterising a solid mass, only MRI can replace the CT scan in most cases. Once a mass has been shown to be solid and vascularised and not occurring in a context suggesting an inflammatory pseudotumour, it can be put, using CT, into one of the four categories of the classification that we propose: pseudotumoral dysmorphisms (type 1); typical high-fat angiomyolipomas (type 2); suspect indeterminate tumours (type 3); typically malignant tumours (type 4).

A Practical Approach to Indeterminate and Cystic Renal Masses

Cystic renal masses are a common entity with a wide differential diagnosis encountered by the radiologist in daily practice. Their characterization relies on the Bosniak classification system that has been widely accepted by radiologists and urologists as a pertinent diagnostic and communication tool. It has been designed to separate cystic lesions requiring surgery (categories III and IV) from those that can be ignored and left alone (categories I and II) or followed (category IIF). Utilization of the Bosniak classification requires, first, previous identification of the cystic nature of a renal mass with the exception of very small lesions.

Ablative Therapies for Renal Tumors: Patient Selection, Treatment Planning, and Follow-Up

The increased use of abdominal imaging has led to a major increase in small renal tumors incidence particularly in the elderly population. Their management is evolving with the development of percutaneous ablation, particularly radiofrequency ablation, cryoablation, and microwave ablation. The typical indications that must be validated by a multidisciplinary committee include solid tumors less than 3cm in patients with multiple comorbidity factors (including age), contraindications to surgery, hereditary renal cancer, bilateral renal tumors, solitary kidney, pre-existing chronic kidney disease, or at high risk of predialysis renal function after partial nephrectomy. As tumor ablation offers almost similar oncologic outcome when compared with surgery, new indications are appearing such as larger tumors, benign, or cystic neoplasms. The biopsy of solid renal masses is recommended in most cases. Careful and systematic treatment planning is required to avoid complications, paying specific attention of the relationships to the bowel structures, and urinary tract. Specific maneuvers can be necessary such as gas or liquid dissection and pyeloperfusion. The technique of ablation depends on availability, training, and tumor size and location, with a preference to cryotherapy for central and large lesions. Evaluation of therapeutic efficacy relies on contrast-enhanced imaging (computed tomography, magnetic resonance imaging or even ultrasound). The follow-up must be continued up to 10 years after ablation. The overall efficacy is more than 90% with a reduced complication rate less than 10%. Renal tumor percutaneous ablation is sparing the renal function and should be the preferred treatment in the case of pre-existing chronic kidney disease.

Aspects radiologiques des métastases des cancers urologiques

Metastases from cancers in urology do not exhibit specific radiological patterns that would allow identification of the primary site. Their detection relies upon usual imaging techniques, and mainly contrast-enhanced Computed Tomography (CT) that allows the study of the thorax, the abdomen and the pelvis. Ultrasound imaging, and the up-to-date contrast-enhanced ultrasound imaging, as well as Magnetic Resonance Imaging are used in addition to CT in case of contra indication of iodinated contrast agents or for targeted indications (focal liver lesion characterization, MR lymphography for lymph node metastases...). PET CT is playing an increasing role but its performances remain limited for the detection of urological metastases. New anti-angiogenic drugs are questioning the traditional evaluation of the therapeutic response based on RECIST criteria. They require more and more the use of functional imaging techniques, such as MRI or CT dynamic studies as well as contrast-enhanced ultrasound.Resume Les metastases des cancers urologiques ne presentent pas de particularite radiologique qui permet de les identifier. Leur recherche fait appel aux techniques habituelles d’imagerie, avec au premier plan la tomodensitometrie (TDM) qui permet l’etude au cours du meme examen du thorax, de l’abdomen et du pelvis. L’echographie et aujourd’hui de plus en plus l’echographie de contraste (echographie realisee apres injection d’un agent de contraste ultrasonore) ainsi que l’IRM sont proposes en complement lors de contre indication a l’injection du produit de contraste iode ou pour des indications ciblees (lesions focales hepatiques, lympho-IRM a la recherche d’adenopathie pelvienne…). Le PET-scan tend a occuper une part grandissante mais avec des performances limitees concernant les metastases des cancers urologiques. L’introduction des nouveaux agents anti-angiogeniques remet en question l’evaluation de la reponse therapeutique basee sur les criteres RECIST. Celle-ci fait de plus en plus appel aux techniques d’imagerie fonctionnelle, comme l’IRM ou la TDM dynamique et de plus en plus l’echographie de contraste.

Renal Pseudo-Tumor Related to Renal Splenosis: Imaging Features

OBJECTIVE To report the case of a 29-year-old patient presenting with renal splenosis along with a complete review of literature on this condition. Splenosis is a frequent condition following abdominal trauma or splenectomy, described as splenic tissue that autotransplants into a heterotopic location. However, renal splenosis is rare and often mistaken with renal carcinoma. MATERIALS AND METHODS The patient was initially referred to our department for a renal mass incidentally discovered on ultrasound. Further investigation included with computed tomography and magnetic resonance imaging. RESULTS Imaging features revealed a well circumscribed solid renal mass, exhibiting an isosignal on T1- and T2-weighted sequences in comparison with the renal cortex. The mass exhibited a heterogeneous enhancement on the arterial and portal phases, homogeneous patterns during the delayed phases, and high signal intensity on diffusion-weighted images. A partial nephrectomy was performed and pathological examination revealed the final diagnosis of renal splenosis. CONCLUSION Imaging features alone do not provide a definitive diagnosis of splenosis but suggestive past history associated with imaging findings consistent with splenic tissue should lead to 99m technetium-sulfur colloid scanning or ferumoxid-enhanced MRI to avoid useless surgery.

Imaging of Human Neurolisteriosis: A Prospective Study of 71 Cases

Background Neurolisteriosis ranks among the most severe neurological infections. Its radiological features have not been thoroughly studied. We describe here the neuroradiological features of neurolisteriosis and assess their prognostic value. Methods Patients with microbiologically proven neurolisteriosis were enrolled from November 2009 to October 2013 in MONALISA study. Magnetic resonance and computed tomography images were studied by 2 independent neuroradiologists. Predictors of 3-month mortality were determined using logistic regression. Results Seventy-one patients were included; 42 were men (59%). Mean age was 64 years. Sixty patients (85%) reported signs of encephalitis, with clinical brainstem involvement in 16 (23%). Images were abnormal in 87% of cases (62/71). Main neuroradiological images were meningeal enhancement (25/71, 35%), abscess(es), or nodular image(s) evocative of abscess (10/71, 14%), hemorrhages (11/71, 15%), contrast-enhancing ventricles, or hydrocephalus (7/71, 10%). White-matter images (42/71, 59%), dilated Virchow-Robin spaces (22/71, 31%), and cerebral atrophy were also reported (34/71, 48%). Brainstem involvement (meningeal enhancement, abscess) was reported in only 7/71 cases (10%). Three-month survival was lower in patients with hydrocephalus or contrast-enhancing ventricles (1/7 [14%] than without [47/64, 73%], P = .005) and in patients with parenchymal images (abscess[es], nodule[s]\, or white matter images; 25/46 [54%] vs 23/25 without [92%], P = .004). Parenchymal images were associated with lower 3-month survival in the multivariable model (odds ratio 5.60, 95% confidence interval [1.42-29.6], P = .02). Conclusions Neurolisteriosis presents as a combination of neuroradiological images, none being specific. Radiological signs of rhombencephalitis are uncommon, whereas, unexpectedly, hemorrhagic images are frequent. The negative prognostic value of parenchymal neuroradiological images was evidenced. Clinical Trials Registration NCT01520597.

Imaging of Renal Vasculitis

Systemic vasculitis encompasses a wide spectrum of inflammatory disorders involving blood vessels of varying size. The kidney is frequently involved because of a high degree of vascularity including blood vessels of varying diameter from large vessels to capillaries. Imaging investigations are often helpful to secure diagnosis of renal vasculitis, assess vascular complications and monitor response to treatment. Whereas angiography is no more performed in most cases it remains the gold standard in detecting renal artery microaneurysms. Cross sectional imaging modalities provide accurate assessment of vascular complications and occasionally diagnostic findings in vasculitis with intrarenal macroaneurysms. Finally, contrast-enhanced US is a new promising non-nephrotoxic modality with the potential to provide similar information compared to CT and MRI.

Cystic Renal Masses

Cystic renal masses result from a wide spectrum of pathology including renal cysts, benign cystic lesions of nonepithelial origin, benign cystic neoplasms, and cystic carcinomas. Whereas the diagnosis of a simple renal cyst is easy, differentiation between complex cyst and cystic renal tumor can be difficult. Ultrasonography provides definitive diagnostic informations in most simple renal cysts that are incidentally screened. Computed tomography (CT) is the gold standard in detecting and characterizing cystic renal masses. The Bosniak classification system is based on specific CT criteria that rely on the cystic lesion enhancement properties and morphologic features. This classification scheme has been designed to separate cystic lesions requiring surgery (surgical categories III and IV) from those that can be left alone (nonsurgical categories I and II) or followed (nonsurgical category IIF). MRI is now considered at least equivalent to CT in the characterization of cystic lesions. It also plays a major role in the diagnosis of category IIF cystic renal masses and those that remain not categorizable at CT. Contrast-enhanced ultrasound has also been shown to improve the evaluation of complex cystic masses. It can be currently proposed as an alternative to CT in the follow-up of complex renal cysts and in patients with serious contraindication to contrast-enhanced CT or MRI.

Apport des produits de contraste en imagerie vasculaire

Resume L’etude ultrasonore des anomalies macrovasculaires repose sur les techniques de Doppler. L’introduction des agents de contraste ultrasonore de derniere generation pourrait ameliorer la qualite de l’examen en cas de difficultes techniques, ainsi que la caracterisation des lesions et les repercussions sur la microcirculation d’aval. Les nouveaux agents possedent des proprietes acoustiques permettant d’obtenir un signal intense, alors que la puissance acoustique est faible et permet d’effectuer l’examen en temps reel. Ils permettent d’opacifier la lumiere vasculaire avec une resolution elevee, superieure a celle du Doppler couleur ou puissance, grâce a des sequences d’imagerie specifiques. Ces nouvelles modalites reposent sur la detection des frequences fondamentales et harmoniques obtenues par la resonance des microbulles. Dans une approche parallele a celle de l’angiographie, ils ameliorent l’etude directe des anomalies vasculaires (stenoses, anevrisme). Ils permettent aussi d’etudier le retentissement distal des stenoses vasculaires, grâce au developpement de l’imagerie fonctionnelle. La plupart des essais cliniques concernant ces applications a ete realisee en imagerie conventionnelle Doppler, et il reste indispensable d’evaluer l’apport de l’echographie de contraste en pathologie vasculaire au cours d’essais multicentriques.