Tubulocystic renal cell carcinoma: a new radiological entity

Tubulocystic 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.

Update on ultrasound elastography: miscellanea. Prostate, testicle, musculo-skeletal

Nowadays ultrasound elastosonography is an established technique, although with limited clinical application, used to assess tissue stiffness, which is a parameter that in most cases is associated with malignancy. However, although a consistent number of articles have been published about several applications of elastosonography, its use in certain human body districts is still not well defined. In this paper we write on the use of elastosonography in prostate, testicle and musculo-skeletal apparatus. We report and compare the work of several authors, different type of elastosonography (shear wave, strain elastography, etc.) and instrumental data obtained in the study of both benign and malignant lesions.

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).

[Renal failure: diagnostic work-up]

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.

[The imaging aspects of metastases from urological malignancies]

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.

Adénome oncocytaire du rein : redéfinition des critères diagnostiques en tomodensitométrie

PURPOSE

To redefine and evaluate the computed tomographic criteria for the diagnosis of renal oncocytoma (RO) for which renal sparing surgery should be preferred.

MATERIAL AND METHOD

Retrospective study of 57 patients with 69 RO. Macroscopic and histological correlation was obtained in all cases. A double blinded comparative study was made of 60 renal tumors (containing adenocarcinomas and oncocytomas) larger than 3 cm in diameter in order to evaluate the redefined CT diagnostic criteria.

RESULTS

Among RO larger than 3 cm in diameter, 55% presented a sharply defined low attenuation scar on post-contrast scans at the tubular nephrographic phase, central or eccentric, with homogeneous attenuation throughout the remainder of the hypervascular tumor which was classified in 3 different groups. The use of our CT diagnostic criteria gave a statistically significant (p < 0.05) Kappa index of inter-observer concordance of 0.71 and a specificity of 96% for the diagnosis of RO.

CONCLUSION

Our redefined computed tomographic criteria for the diagnosis of renal oncocytoma, eventually associated with renal biopsy, should increase the indications for renal sparing surgery for RO larger than 3 cm in diameter.

[The role of contrast-enhanced ultrasonography for the detection of hepatocellular carcinoma]

The incidence of the hepatocellular carcinoma (HCC) is increasing in Occident, as well as in France. Primary prevention is the only solution for early detection. The combination of ultrasound (US) and alphaFP each 4 to 6 Months dosage has many limitations. The sensitivity of US examination is rather poor (less than 70% for lesions below 2 cm in diameter) and serum alphaFP values remain normal in almost 50% of HCC. US contrast agents (USCAs) with perfluorocarbon gases increase the backscattered signals during all phases of the liver transit, including arterial, portal and delayed phases. Hepatocellular lesions exhibit a specific kinetics with strong enhancement during arterial phase, and rapid wash-out during portal and delayed phases. USCAs increase the detection of HCCs and allow characterization of additional focal lesions found in cirrhotic livers (regenerative and dysplastic nodules, haemangiomas.). Indeed, regenerative nodules contrast uptake is synchronous to the surrounding parenchyma, and usually disappear during portal and delayed phases. However, US in cirrhosis remains a difficult examination, with limitations due to limited access to sub-diaphragmatic localization, attenuation of the ultrasound beam and shortness of the arterial phase.

[Diagnostic imaging of peripheral renal vascular disorders]

Peripheral vascular disorders of the kidney involve the intrarenal branches of the renal vascular tree. It include occlusive (infarction and cortical necrosis) and non-occlusive vascular lesions (acquired arteriovenous fistulas, arteriovenous malformation, false aneurysms and microaneurysms). Initial diagnosis relies on color Doppler US and CT angiography. Angiography plays a therapeutic role. MR imaging provides useful diagnostic information on perfusion disorders especially in patients with renal insufficiency.

[Urinary tract imaging: conventional radiology and ultrasound]

Conventional radiology includes intravenous urography for evaluation of the entire urinary tract and direct opacifications by retrograde cystography, supra-pubic cystography, and retrograde urethro-cystography for evaluation of the lower urinary tract. Intravenous urography remains the gold standard for evaluation of the upper excretory tract. The accuracy of ultrasound examination has increased with the availability of multiple frequency probes, harmonic imaging and color Doppler imaging. Because it is non-invasive, ultrasound now is the first line imaging technique for evaluation of the renal parenchyma, renal vessels and bladder.

Abdominal wall and surgical scar endometriosis: results of magnetic resonance imaging

Scar endometriosis is a rare disease which is difficult to diagnose. The symptoms are nonspecific, typically involving abdominal wall pain at the time of menstruation. Clinical examination may reveal a painful nodule, if the scar involved is located on the abdominal wall, but is normal, when the lesion is located on the uterine scar. Other means of investigation (transvaginal ultrasonography, computed tomography) may be useful in case of lesions on the abdominal wall, or if the nodule is large, but give no specific results. The diagnosis is frequently made only after excision of the lesion. We report here 4 patients operated for scar endometriosis (two abdominal and two uterine scars) for whom MRI had suggested the diagnosis. Thanks to its very high spatial resolution, MRI enables very small lesions to be detected and can distinguish the hemorrhagic signal of endometriotic lesions. Furthermore, it performs better than the CT scan in detecting the limits between muscles and abdominal subcutaneous tissues.

[Contrast-enhanced ultrasonography: renal applications]

Color Doppler US of the urinary tract is still facing a few limitations including, for B-mode imaging, the detection of small lesions, and, for color Doppler, the detection of low flow. Ultrasound contrast agents (USCA) improve these two limitations and allow the development of new functional applications for renal blood flow quantification. This improvement results from an increased acoustic response obtained from the microbubbles, as well as from the development of pulse sequencing and signal processing that led to the concept of specific ultrasound sequences. Most of the clinical indications of contrast-enhanced ultrasonography remain to be validated with the improved detection of the non linear response. USCA improve the detection of abnormal micro and macrovascular disorders of the kidney, particularly for the detection and the characterization of renal artery stenosis, as well as for the visualization of renal infarction. This technique showed potentials for the study of renal masses, especially atypical cystic lesions. Among the remaining indications, the detection of reflux and testicular torsion are the most promising.

Ultrasound of renal tumors

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.

[Characterization of renal masses]

The characterization of renal masses relies mainly on CT which remains the gold standard in the diagnosis of renal tumors and cysts. Ultrasound enables to diagnose benign cysts which account for the majority of incidentally detected renal masses. MR imaging is useful in the diagnosis of renal masses that remain indeterminate at CT. Moreover, it is efficient as a substitute when CT is contraindicated. Renal masses include three categories with respect to the size and the gross architecture of the lesion: indeterminate very small masses (less than 10mm in diameter); cystic renal masses and solid renal masses that exhibit postcontrast tumor tissue enhancement. Characterization of cystic renal masses relies mainly on the Bosniak classification which consists of four categories: benign simple cysts (cat I); minimally complicated cysts (cat II); indeterminate cystic renal masses that include cystic renal tumors (multiloculated or not) and complex cysts; cystic renal cell carcinomas (cat IV). Solid renal masses include pseudotumors (normal variants, renal dysmorphisms and inflammatory renal masses) and renal neoplasms among which CT enable to distinct: typical large renal cell carcinomas, typical fat-containing angiomyolipomas and indeterminate renal tumors.

[Kidney tumors: clinical and pathological findings and detection]

The detection and the clinical and pathological findings of kidney tumors have much progressed over the last 15 years. The incidence of asymptomatic renal masses has increased up to 30% during this time. This is mostly due to advances in ultrasound and computed tomography imaging. So, the therapeutic management of these masses has also been significantly changed. A better knowledge of their clinical and anatomical features allowed a more efficient mutlidisplinary approach and a better assessment of their prognosis.

Comparison of magnetic resonance imaging and transvaginal ultrasonography in diagnosing bladder endometriosis

STUDY OBJECTIVE

To take recent progress in magnetic resonance imaging (MRI) into account to determine its accuracy compared with that of transvaginal ultrasonography (TVUS) in diagnosing bladder endometriosis.

DESIGN

Retrospective analysis (Canadian Task Force classification II-2).

SETTING

University-affiliated hospital.

PATIENTS

Twelve women with histologically proved bladder endometriosis.

INTERVENTION

Magnetic resonance imaging with body and endocavitary coils and TVUS.

MEASUREMENTS AND MAIN RESULTS

Although TVUS was normal in four patients, MRI enabled endometriotic lesions to be detected in all patients. Magnetic resonance imaging with endocavitary coil established the existence of deep infiltration in three patients when muscularis involvement was not visible with the body coil. In seven women MRI determined how far deep posterior endometriotic lesions extended, whereas with TVUS this was impossible to see. Conclusion. MRI had advantages over TVUS in diagnosing small lesions of associated posterior deep endometriotic lesions. The endocavitary coil gave better results than the phased-array coil for diagnosing deep infiltration. These results are important in that they help guide surgical management.

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

The concept of contrast imaging was introduced to ultrasound almost 30 years 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 nonlinear 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.

Endorectal color doppler sonography and endorectal MR imaging features of nonpalpable prostate cancer: correlation with radical prostatectomy findings

OBJECTIVE

The purpose of this study was to describe endorectal sonography and color Doppler sonography features of nonpalpable prostate cancer and to assess the value of endorectal MR imaging for the preoperative local staging of these tumors.

MATERIALS AND METHODS

Ninety-four patients with nonsuspicious findings on digital rectal examination and a mean prostate-specific antigen level of 16.3 +/-10 ng/mL (median, 13 ng/mL) underwent endorectal sonography, color Doppler sonography, sextant endorectal sonographically guided biopsy, and endorectal MR imaging before radical prostatectomy.

RESULTS

Tumors were visible in 48 cases and not visible in 46. The mean Gleason biopsy score, the frequency of tumors involving three sextants or more of the prostate gland at biopsies, and the frequency of stage pT3 tumors were significantly higher in patients with visible tumors (5.9+/-0.9, 42%, and 37.5%) than in those with invisible tumors (5.4+/-1.1, 17%, and 17%). The 42 hypervascular tumors were hypoechoic in every case and had a higher rate of Gleason tumor grades 4 and 5 at biopsy than did the 52 hypovascular tumors (33% versus 11.5%). Six hypovascular tumors (6/52, 11.5%, two visible) had an insignificant tumor volume. Established extraprostatic tumor spread was detected on MR imaging in six of 18 cases (sensitivity, 33%; specificity, 100%0, all of which had the following four features: hypervascularity, prostate-specific antigen level greater than 20 ng/mL, three or more sextants of the gland having positive findings at biopsy, and seminal vesicle invasion.

CONCLUSION

Endorectal sonography and color Doppler sonography are useful to differentiate low-risk invisible and hypovascular tumors from high-risk visible and hypervascular tumors. However, MR imaging has a poor sensitivity for the detection of extraprostatic spread and is accurate only in a minority of highly selected high-risk hypervascular tumors.

[Renal sinus disorders: imaging findings and pitfalls]

Renal sinus pathology can be classified into 3 groups: intrinsic lesions that arise from the anatomical components of the sinus (fatty tissue, collecting system, arteries and veins, lymphatic vessels, and nerves); extrinsic lesions that develop within the renal sinus from the renal parenchyma; secondary lesions including metastases and retroperitoneal tumors with renal sinus involvement. The diagnosis of renal sinus disorders often relies on a multimodality approach including IVU, doppler-ultrasonography, and CT. The wide variety of renal sinus diseases that may origin either from the renal parenchyma or the retroperitoneum, and the numerous pitfalls mostly due to anatomic variations, may prevent from making a right etiological diagnosis in numerous cases.

Imaging evaluation of renal trauma

The kidney is the most commonly injured genitourinary organ. The diagnosis and treatment depend on the mechanism of injury (blunt or penetrating trauma), the clinical presentation, and the extent of the lesions. Knowledge of the different appearances of the posttraumatic kidney on imaging studies is essential for prompt and effective treatment of patients. This pictorial essay reviews the imaging evaluation and principal imaging findings associated with blunt and penetrating renal trauma. The role of computed tomography is emphasized because it is a very sensitive, specific, and accurate modality in detecting the presence or absence of injury and defining its extent.

[Value of MR imaging in the diagnosis of benign uterine conditions]

Benign diseases of the uterus can be evaluated by ultrasound, magnetic resonance imaging (MRI), hysterography, hysterosonography and hysteroscopy. The purpose of this review of the literature is to discuss the role of MRI among the different imaging modalities for the diagnosis of mullerian abnormalities of the uterus, endometrial disease, fibroids and adenomyosis. Particular attention is brought to comparative multi-modality studies. The MRI technique, indication and diagnostic criteria for various pathological conditions of the uterus are described. The use of MRI appears to be cost-effective in the diagnosis of complex mullerian abnormalities, endometrial thickening following treatment by tamoxifen, selection of candidates for selective myomectomy and the follow-up of medically treated adenomyosis.

[Ultrasound contrast agents]

Ultrasound contrast agents are introducing a new vision to ultrasonography. The increase in the Doppler signal intensity improves difficult examinations. Technical failures in the study of transcranial, liver and renal vessel might be rescued with the injection of these new compounds. The introduction of specific image sequences such as harmonic imaging and pulse inversion imaging allows detection of parenchymal enhancement in liver and renal examinations. The injection of ultrasound contrast agents also provides dynamic quantitative information to develop functional imaging. However, it is mandatory to understand the interaction with the ultrasound beam in order to optimise their use and define the adequate ultrasound sequence.

Percutaneous incision of stenotic uroenteric anastomoses with a cutting balloon catheter: long-term results

PURPOSE

To describe the technique and results of incision of strictures in anastomotic urinary diversions with a commercially available cutting balloon catheter.

MATERIALS AND METHODS

Thirty-seven stenoses were treated in 32 patients. Most (28 [88%]) of the patients had undergone surgery for bladder cancer 17.7 months +/- 17.4 (SD) (range, 3-72 months) before incision. Thirteen patients had undergone ileal conduit diversion, and nineteen had undergone enterocystoplasty. All stenoses were shorter than 3 cm. The presence of adjacent ileal loops and/or iliac vessels was assessed with computed tomography before incision. The cutting wire was oriented anteriorly or anterolaterally, and the balloon was inflated with diluted contrast material during the incision. A Kaplan-Meier survival curve was constructed to illustrate the success rates over time.

RESULTS

No major complications occurred. Twelve (32%) stenoses recurred in nine patients 15 months +/- 10 (range, 6-36 months) after stent removal; the failure rate was 53% (eight of 15 stenoses) for ileal conduits and 18% (four of 22 stenoses) for enterocystoplasties. Late failure (>12 months) was observed in four patients. The patency of the other 25 stenoses (23 patients) was checked 25 months +/- 11 after stent removal (range, 5-43 months). The actuarial patency rate was 77% at 1 year, 68% at 2 years, and 62% at 3 years.

CONCLUSION

Cutting balloon incision is a safe and simple alternative to surgery, particularly when the urinary diversion is enterocystoplasty.

[Radiological diagnosis of renal sarcoidosis]

We report a case of renal sarcoidosis revealed by a malignant hypertension associated with renal insufficiency. Ultrasonographic and CT findings are described. The lesions showed multifocal hypoechogenic areas within the renal parenchyma. The disease was pathologically proved after US guided biopsy.

Doppler ultrasonography of peripheral vascular disease: the potential for ultrasound contrast agents

Noninvasive diagnosis of peripheral vascular disease started with the introduction of Doppler technology. The development of high frequency ultrasound and color Doppler imaging allows continuous assessment of vascular disorders along the arterial tree. However, the technique remains operator dependent. It also suffers from anatomic limitations, such as bowel gas and ultrasound attenuation due to depth or wall calcification. Ultrasound contrast agents increase the Doppler signal intensity and should therefore reduce the rate of technical failures. They are useful for detecting the flux in cases of attenuated ultrasound beam and reduced blood flow. Their administration using continuous infusion protocols increases the duration of the effect. New imaging modalities such as harmonic imaging and pulse inversion imaging reduce Doppler artifacts and allow real time detection of the microbubbles flowing in the blood stream. Future directions include ultrasound-guided therapy of occlusion using encapsulated drugs targeted to the thrombus.

Varicocele: strategies in diagnosis and treatment

Varicocele can be very easily diagnosed by physical examination and subsequently treated when it is painful or associated with testicular hypotrophy. However, palpability of the spermatic vein and reflux in low grade or even questionable varicoceles can be difficult to assess without imaging modalities. This can be a common problem for all physicians treating hypofertile men to decide whether the varicele needs to be treated or not. However, a gold standard that defines the presence of a subclinical varicocele has not yet been established. The different diagnostic tools based on ultrasonography investigated these past years to define a flow reversal in incontinent spermatic veins are presented in the first part of this review, with emphasis on subclinical varicocele. In the second part, we present our experience, together with a review of the literature concerning embolization of the spermatic veins as an alternative to surgery to treat varicoceles.

[Imaging of thyroid nodules]

Ultrasonography and scintigraphy are the first line diagnostic imaging modalities for the evaluation of thyroid nodules. Scintigraphy provides functional informations, mainly detection of hot nodules. US provides accurate morphologic evaluation and it may sometimes suggest malignancy. US is the modality of choice for follow-up of non resected nodules and is very useful for guidance during biopsy. CT and MRI are mainly used for preoperative evaluation of thyroid nodules.

[Cystic tumors of the kidney in adults: radio-histopathologic correlations]

The purpose of this study is to provide an updated pathologic-radiologic classification of cystic renal tumors and to assess imaging diagnostic capabilities. Eighty seven cases of cystic renal tumors explored with multimodality imaging (ultrasonography, CT, MRI, arteriography) and with histopathologic correlation are reported. The most common cystic carcinomas were multilocular cystic renal cell carcinoma (33%) and the pseudocystic necrotic carcinoma (31%), which usually belong to category IV. Less common cystic carcinomas were unilocular cystic renal cell carcinoma (6%) and renal cyst wall carcinoma (6%). The association of thin septa and large locules are suggestive findings for multilocular cystic nephroma, but such criteria are not specific enough to recognize benign multilocular cystic nephroma and to exclude multilocular cystic renal cell carcinoma. Since carcinomatous degeneration may occur within the wall of such tumors, especially in von Hippel Lindau disease, surgery is still required. The results of our study corroborate the Bosniak classification of cystic renal masses: no tumors belonged to the category I or II, all cystic masses which belonged to the category IV were malignant tumors, category III included benign and malignant tumors.

Renal vascular Doppler imaging: clinical benefits of power mode

Power Doppler ultrasound (US) is a new technology that is superior to conventional color Doppler imaging in the detection of blood flow. Because of its greater sensitivity to flow and reduced angle dependence, power Doppler US demonstrates optimal color filling of renal pedicular vessels and allows improved evaluation of the renal parenchymal microvasculature. Power Doppler US was used as an adjunct to conventional color Doppler imaging in technically challenging cases and to improve evaluation of renal vascular disorders in a series of 916 patients. The primary clinical advantages of using power Doppler US compared with conventional color Doppler imaging include better morphologic appreciation of atherosclerotic changes in the renal artery wall, allowing improved diagnostic performance especially in hemodynamically nonsignificant plaques; ability to differentiate between subocclusive renal artery stenosis and occlusion; increased confidence in the diagnosis of renal vein thrombosis and in the assessment of caval tumor thrombus; and better appreciation of renal cortical perfusion defects. In addition, because of its greater sensitivity to perivascular artifact, power Doppler US has the potential to increase the detection rate for intrarenal arteriovenous fistulas.

Thickening of the wall of the bile duct due to intramural collaterals in three patients with portal vein thrombosis

OBJECTIVE

We report three cases of a rare form of cavernoma developed within the wall of the common bile duct.

CONCLUSION

To our knowledge, this kind of portal cavernoma has not been described in the literature. Because the cavernoma may be easily confused with other causes of bile duct wall thickening, color Doppler sonography is mandatory for a correct diagnosis.

Imaging of obstructive azoospermia

Obstructive azoospermia represents approximately 10 % of cases of male hypofertility. It is classified according to the volume of ejaculate. When the latter is normal a proximal obstruction is suspected. Scrotal sonography can help to detect dilation of the epididymal head when clinical findings are equivocal. Ejaculatory duct obstruction (EDO) is suspected when the volume of ejaculate is low. The use of transrectal ultrasonography (TRUS) plays a major role in the investigation of these patients, and endorectal MRI is a very useful adjunct in selected cases. The most common cause of EDO is congenital bilateral absence of vas deferens, which is now thought to be a genital form of cystic fibrosis in 80 % of cases. Consequently, a definitive diagnosis must be made before any attempt at in vitro fertilization. TRUS accurately visualizes abnormalities of the caudal junction of the vas deferens and seminal vesicles, yielding a definitive diagnosis without scrototomy. Other causes of EDO are congenital cysts compressing the distal part of the ejaculatory ducts and inflammatory distal stenosis. The former are accurately identified by TRUS, but the latter give more or less marked signs of obstruction which are only of value in azoospermic patients with a low-volume ejaculate. More invasive imaging is required to diagnose partial obstruction of the ED. Surgical vasography is still the reference, but puncture of the seminal vesicles under TRUS guidance is an attractive alternative, as it permits aspiration of seminal fluid (to seek motile sperm) and vasography without scrototomy. Lastly, endorectal MRI well assesses the relationships between the proximal prostatic urethra and the posterior wall of the ejaculatory ducts, which need to be precisely known when endoscopic resection of the ejaculatory ducts is planned.

Color Doppler-guided prostate biopsies in 591 patients with an elevated serum PSA level: impact on Gleason score for nonpalpable lesions

OBJECTIVES

To compare results of color Doppler-guided ultrasonography (CDUS) versus those of systematic biopsies in 591 patients with an elevated serum PSA level and to correlate them with digital rectal examination (DRE) findings.

METHODS

Biopsies were directed into hypervascularized (CDUS+) or hypovascularized (CDUS-) hypoechoic peripheral zone nodules (443 cases). When transrectal ultrasound (TRUS) was normal (148 cases), biopsies were directed into hypervascular area. Six additional posterior biopsies were also performed in every patient, together with four anterior biopsies in 117 patients with normal DRE and prostate weight above 40 g.

RESULTS

Biopsies were positive in 339 patients (57%). Positive biopsy rate (PBR) of directed biopsies was 84% in hypervascular abnormalities (264 of 316) and 17% in hypovascular nodules (23 of 134) (P < 0.001). PBR of combined biopsies was 84% in CDUS+ patients (266 of 316) and 26% in CDUS- patients (73 of 275) (P < 0.001). Comparison of TRUS and CDUS showed a sensitivity of 0.9 and 0.78, respectively, and a specificity of 0.46 and 0.8, respectively. Of the 131 patients with a PSA level between 4 and 10 ng/mL and a normal DRE, PBR was 59% (22 of 37) when CDUS was positive and 11% (10 of 94) when it was negative, regardless of TRUS abnormalities (P < 0.001). Nonpalpable cancers with a negative CDUS showed a significantly (P < 0.001) lower Gleason score (5.5 +/- 0.9) than that of CDUS+ cancer (6.5 +/- 1.1). Eleven cancers were diagnosed by only anterior positive biopsies. All of them had a negative CDUS and a PSA level above 10 ng/mL.

CONCLUSIONS

CDUS does not modify prostate biopsy policy except in patients with negative CDUS, normal DRE, and PSA level between 4 and 10 ng/mL, where deferment of biopsy can be advocated. Anterior biopsies are only useful in patients with a PSA level above 10 ng/mL and a negative CDUS.

Renovascular disease: Doppler ultrasound

Color Doppler ultrasound (CDUS) seems to be an effective imaging technique for the diagnosis of renal vascular diseases. It is already the modality of choice for the detection of acute renal vein thrombosis and nonocclusive intrarenal vascular disorders including iatrogenic arteriovenous fistula and false aneurysm, particularly in patients with impaired renal function that precludes the use of iodinated contrast agents. Although proximal Doppler interrogation remains an important step in diagnosing renal artery (RA) stenosis, useful hemodynamic information can be obtained from the distal arterial bed. When CDUS fails in identifying proximal RAs, normal waveform velocity and morphology obtained from intrarenal arteries enable one to rule out RA occlusion and most of the severe stenoses (> or = 80%). Such information, which is not subject to a significant risk of technical failure, seems to be particularly useful in studying patients with acute renal failure of suspected vascular origin. Despite the extreme variability in reported performance between studies, CDUS has seemed to be a valuable tool compared with other noninvasive modalities in the diagnosis of RA stenosis. Whereas a CDUS-based strategy is already accepted in numerous specialized centers, a thorough evaluation of diagnostic criteria and extensive training of operators will allow CDUS to be widely accepted for the screening of patients at high risk for renovascular hypertension.

Unusual fat-containing tumors of the kidney: a diagnostic dilemma

Unusual fat-containing renal tumors in a series of 27 cases comprised five categories: atypical and complicated angiomyolipomas (AMLs) (n = 15), including AMLs with extrarenal growth (n = 5), AMLs with undetectable fat (n = 4), and hemorrhagic AMLs (n = 6); fat-containing renal cell carcinomas (RCCs) (n = 9); lipoma (n = 1); liposarcoma (n = 1); and fat-containing renal oncocytoma (n = 1). Fat was present within RCCs by the following mechanisms; lipid-producing necrosis within a large RCC (n = 2), intratumoral bone metaplasia with fatty marrow elements and calcification within a small RCC (n = 2), and entrapment of perirenal (n = 4) or sinus (n = 1) fat by large irregular RCCs. Fat-containing RCC must be considered in cases of fat-containing renal tumors, even though the presence of intratumoral fat is characteristic of AML. A dedicated computed tomography scanning protocol and strict diagnostic criteria are mandatory for accurate diagnosis. Malignancy should be suspected on the basis of the following criteria: presence of intratumoral calcifications; large, irregular tumor invading the perirenal or sinus fat; large necrotic tumor with small foci of fat; and association with nonfatty lymph nodes or venous invasion.