The role of the radiologist in the evaluation of male infertility: recommendations of the European Society of Urogenital Radiology-Scrotal and Penile Imaging Working Group (ESUR-SPIWG) for scrotal imaging.

OBJECTIVES: The Scrotal and Penile Imaging Working Group (SPIWG) of the European Society of Urogenital Radiology (ESUR) aimed to produce recommendations on the role of the radiologist in the evaluation of male infertility focused on scrotal imaging. METHODS: The authors independently performed an extensive literature Medline search and a review of the clinical practice and consensus opinion of experts in the field. RESULTS: Scrotal ultrasound (US) is useful in investigating male infertility. US abnormalities related to abnormal sperm parameters (sperm concentration, total count, motility, and morphology) are low testicular volume (TV), testicular inhomogeneity (TI), cryptorchidism, testicular microlithiasis (TML), high-grade varicocele, bilateral absence of vas deferens, bilateral dilation and echotexture abnormalities of the epididymis. The proposed ESUR-SPIWG recommendations for imaging in the evaluation of male infertility are therefore: to measure TV; investigate TI; perform annual (US) follow-ups up to age 55 in men with a history of cryptorchidism/orchidopexy and/or in men with TML plus "additional risk factors" or with "starry sky" TML; perform scrotal/inguinal US in men with nonpalpable testis; perform scrotal US in men with abnormal sperm parameters to investigate lesions suggestive of tumors; evaluate varicocele in a standardized way; evaluate the presence or absence of vas deferens; investigate the epididymis to detect indirect signs suggesting obstruction and/or inflammation. CONCLUSIONS: The ESUR-SPIWG recommends investigating infertile men with scrotal US focusing on TV, inhomogeneity, localization, varicocele, vas deferens, and epididymal abnormalities. Cryptorchidism, TML, and lesions should be detected in relation to the risk of testicular tumors. CLINICAL RELEVANCE STATEMENT: The ESUR-SPIWG recommendations on scrotal imaging in the assessment of male infertility are useful to standardize the US examination, focus on US abnormalities most associated with abnormal semen parameters in an evidence-based manner, and provide a standardized report to patients. KEY POINTS: So far, ESUR-SPIWG recommendations on scrotal imaging in the assessment of male infertility were not available. The ESUR-SPIWG recommends investigating infertile men with scrotal US focusing on testicular volume, inhomogeneity, localization, varicocele, vas deferens and epididymal abnormalities, and assessing cryptorchidism, testicular microlithiasis and lesions in relation to the risk of testicular tumors. The ESUR-SPIWG recommendations on scrotal imaging in the assessment of male infertility are useful to standardize the US examination, focus on US abnormalities most associated with abnormal sperm parameters in an evidence-based manner, and provide a standardized report to patients.

The genitourinary system in ancient Greece: a historical perspective.

The Ancient Greeks were great innovators in all academic fields, including medicine. Hippocrates of Kos, the Father of Medicine, established many terms for the genitourinary (GU) system, such as nephros, urethra, urogenital, and adenocarcinoma. According to Hesiod's Theogony, Aphrodite, the goddess of love and beauty, was born off the coast of Kythera, from the foam produced by Uranus's genitals, after his son Cronus had thrown them into to the sea. In this review, we present the etymology of the GU vocabulary, review the Ancient Greeks' understanding of the GU system and the origins of Greek myths related to the male genitals.

Dynamic contrast-enhanced MRI in the assessment of testicular perfusion in infertile men with clinical varicocele.

BACKGROUND: Varicocele represents the most common correctable cause of male infertility. The presence of non-invasive imaging parameters providing evidence as to which patients with varicocele are at risk for infertility would be important. PURPOSE: To explore the role of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) using semi-quantitative parameters in the assessment of testicular perfusion in infertile men with clinical varicocele. MATERIAL AND METHODS: The study cohort included 11 infertile men with clinical varicocele and six controls, with prior paternity. Subtraction DCE-MRI was performed after gadolinium administration, using a three-dimensional fast field-echo sequence. Time-signal intensity curves were created and semi-quantitative parameters were calculated. The independent samples t-test was used to compare basic T1 perfusion parameters between infertile testes with clinical varicocele and normal testes. Logistic regression analysis was performed to assess the most significant predictor of the diagnosis of clinical varicocele. RESULTS: Both testes with clinical varicocele and normal testes enhanced moderately and homogeneously, with a linear increase of enhancement throughout the examination. Higher mean values of maximum enhancement (P = 0.026), maximum relative enhancement (P = 0.024), and wash-in rate (P = 0.013) were detected in the testes of infertile men with clinical varicocele, compared to the normal population. The wash-in rate proved the most significant predictor of the diagnosis of clinical varicocele (P = 0.013). CONCLUSION: DCE-MRI may provide a valuable insight into the testicular perfusion of infertile men with clinical varicocele. The wash-in rate proved a strong and independent predictor of the diagnosis of clinical varicocele.

Proton MR Spectroscopy in Assessing the Biochemical Milieu of Human Testes.

Proton magnetic resonance spectroscopy (MRS), considered a connection between metabolism and anatomic and functional information provided by standard MRI, gives information on various tissue metabolites and their pathologic changes. Recently, proton MRS has been added as an adjunct tool to the multiparametric protocol of scrotal MRI, providing a new insight into the extremely complex biochemical milieu of normal and abnormal testes. This article reviews proton MR spectra of normal testes, showing age and bilateralism dependence. Disturbances of various metabolic pathways in testes of infertile men resulting in alterations of metabolite peaks are discussed. Preliminary data on proton MR spectra of testicular mass lesions are presented. LEVEL OF EVIDENCE: 5. TECHNICAL EFFICACY STAGE: 5.

Volumetric apparent diffusion coefficient histogram analysis of the testes in nonobstructive azoospermia: a noninvasive fingerprint of impaired spermatogenesis?

OBJECTIVES: To explore the association between testicular volumetric apparent diffusion coefficient (ADC) histogram analysis metrics and histologic categories in nonobstructive azoospermia (NOA). The role of ADC histogram analysis in predicting the presence of spermatozoa, prior to testicular sperm extraction (TESE), was also investigated. METHODS: Forty-one NOA men and 17 age-matched controls underwent scrotal MRI with diffusion-weighted imaging. Histogram analysis of ADC data of the whole testis was performed. Metrics including mean, standard deviation, median, mode, 25th percentile, 75th percentile, skewness, kurtosis, and entropy of volumetric ADC histograms were calculated. Nonparametric statistical tests were used to assess differences in ADC histogram parameters between NOA histologic categories (hypospermatogenesis, severe hypospermatogenesis, early maturation arrest, and Sertoli cell-only syndrome) and normal testes and, between NOA with positive and negative sperm retrieval. RESULTS: Normal testes had a lower mean, median, mode, 25th percentile (p < 0.001), and 75th percentile of ADC (p = 0.001), compared to NOA histologic phenotypes. NOA with hypospermatogenesis had a lower 25th percentile of ADC compared to NOA with severe hypospermatogenesis. Regression analysis revealed that the 25th percentile of ADC had a moderately negative correlation with NOA histologic phenotype. The median ADC proved the most significant metric (p = 0.007) to predict the presence of sperm. CONCLUSIONS: Testicular volumetric ADC histogram parameters may contribute in the identification of the subpopulation of NOA men with a specific type of spermatogenic arrest. KEY POINTS: • Volumetric ADC histogram analysis metrics may be used as noninvasive markers of impaired spermatogenesis in nonobstructive azoospermia. • The 25th percentile of ADC proved useful in discriminating between NOA testes with hypospermatogenesis and severe hypospermatogenesis. • The median ADC proved the most significant parameter to predict the presence of viable spermatozoa prior to TESE.

Cross-sectional imaging assessment of renal masses with emphasis on MRI.

Magnetic resonance imaging (MRI) is a useful complementary imaging tool for the diagnosis and characterization of renal masses, as it provides both morphologic and functional information. A core MRI protocol for renal imaging should include a T1-weighted sequence with in- and opposed-phase images (or, alternatively with DIXON technique), T2-weighted and diffusion-weighted images as well as a dynamic contrast-enhanced sequence with subtraction images, followed by a delayed post-contrast T1-weighted sequence. The main advantages of MRI over computed tomography include increased sensitivity for contrast enhancement, less sensitivity for detection of calcifications, absence of pseudoenhancement, and lack of radiation exposure. MRI may be applied for renal cystic lesion characterization, differentiation of renal cell carcinoma (RCC) from benign solid renal tumors, RCC histologic grading, staging, post-treatment follow-up, and active surveillance of patients with treated or untreated RCC.

Multidetector computed tomography in diagnosing peritoneal metastases in ovarian carcinoma.

Multidetector computed tomography (MDCT) of the abdomen is currently the imaging examination of choice for the staging and follow-up of ovarian carcinoma (OC). Peritoneal metastases (PMs) represent the most common pathway for the metastatic spread of OC. MDCT scanners, due to several advantages-including increased volume coverage, reduced scanning time, acquisition of thin slices and creation of multiplanar reformations, and three-dimensional reconstructions-provide useful information regarding the early and accurate detection of PMs. Detailed mapping of peritoneal carcinomatosis is feasible, with improved detection of sub-centimeter peritoneal implants and thorough evaluation of curved peritoneal surfaces.

Imaging of colorectal cancer liver metastases using contrast-enhanced US, multidetector CT, MRI, and FDG PET/CT: a meta-analysis.

BACKGROUND: Imaging of colorectal cancer liver metastases (CRCLMs) has improved in recent years. Therefore, the role of current imaging techniques needs to be defined. PURPOSE: To assess the diagnostic performance of contrast-enhanced ultrasound (CEUS), multidetector computed tomography (MDCT), magnetic resonance imaging (MRI), and fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT in the detection of CRCLMs. MATERIAL AND METHODS: PubMed database was searched for articles published during 2000-2019. Inclusion criteria were as follows: diagnosis/suspicion of CRCLMs; CEUS, MDCT, MRI, or FDG PET/CT performed for the detection of CRCLMs; prospective study design; histopathologic examination, intraoperative findings and/or follow-up used as reference standard; and data for calculating sensitivity and specificity reported. RESULTS: Twelve prospective studies were assessed, including 536 patients with CRCLMs (n = 1335). On a per-lesion basis, the sensitivity of CEUS, MDCT, MRI, and FDG PET/CT was 86%, 84%, 89%, and 62%, respectively. MRI had the highest sensitivity on a per-lesion analysis. CEUS and MDCT had comparable sensitivities. On a per-patient basis, the sensitivity and specificity of CEUS, MDCT, MRI, and FDG PET/CT was 80% and 97%, 87% and 95%, 87% and 94%, and 96% and 97%, respectively. The per-patient sensitivities for MRI and MDCT were similar. The sensitivity for MRI was higher than that for CEUS, MDCT, and FDG PET/CT for lesions <10 mm and lesions at least 10 mm in size. Hepatospecific contrast agent did not improve diagnostic performances. CONCLUSION: MRI is the preferred imaging modality for evaluating CRCLMs. Both MDCT and CEUS can be used as alternatives.

In vivo biochemical investigation of spermatogenic status: 1H-MR spectroscopy of testes with nonobstructive azoospermia.

OBJECTIVES: To evaluate the biochemical milieu in testes with nonobstructive azoospermia (NOA) by using proton MR spectroscopy (1H-MRS) in detecting differences in testicular metabolites between histological stages of NOA and in assessing the possible presence of spermatozoa before microdissection testicular sperm extraction (mTESE). METHODS: Forty-nine NOA men and fifty age-matched controls were included in this prospective study. A single-voxel point-resolved spectroscopy sequence with TR/TE (2000/25 ms) was used. NOA testes were classified using the higher Johnsen score (hJS) (group 1, hJS ≥ 8; and group 2, hJS < 8). Nonparametric statistical tests were used to assess differences in normalized metabolite concentrations, defined as ratios of the metabolite concentrations versus creatine concentration between (a) NOA and controls, (b) NOA groups, and (c) NOA with positive and negative sperm retrieval. RESULTS: Normalized concentrations of total choline (median 0.396 vs 1.09 mmol/kg, p = 0.002), myo-inositol (median 1.985 vs 3.19 mmol/kg, p = 0.002), and total lipids and macromolecules (TLM) resonating at 0.9 ppm (median 0.962 vs 2.43 mmol/kg, p = 0.024), 1.3 ppm (median 4.88 vs 10.7 mmol/kg, p = 0.043), and 2.0 ppm (median 2.33 vs 5.96 mmol/kg, p = 0.007) were reduced in NOA testes compared with controls. Decreased concentrations of TLM 2.0 (median 3.755 vs 0.436 mmol/kg, p = 0.043) were found in group 2 compared with group 1. Increased normalized concentrations of glutamate were observed in NOA testes with failed sperm retrieval (median 0.321 vs 0.000 mmol/kg, p = 0.028). CONCLUSIONS: 1H-MRS provides metabolic information about the testis in NOA patients and assesses spermatogenic status before mTESE. KEY POINTS: • NOA testes differed from age-matched controls, in terms of reduced normalized concentrations of tChol, mI, and lipids. • TLM 2.0 peaks were found useful in the identification of NOA testes with the presence of foci of advanced spermatogenesis up to the haploid gamete stage. • Glu proved a reliable metabolic signature of spermatogenesis in NOA population by assessing the possible presence of sperm after mTESE.

Are there differences in the biochemical profile of bilateral normal testes? A 3.0 T 1H-MR spectroscopy study.

Bilateral normal testes asymmetry represents an interesting phenomenon. The aim was to assess possible differences in the biochemical profile of bilateral normal testes by 3.0 T proton magnetic resonance spectroscopy (1H-MRS). Twenty-one men were examined with scrotal 3.0 T MRI, including a single-voxel point-resolved spectroscopy sequence. MR spectra were obtained by placing a volume of interest in the middle of each normal testis. Normalised metabolite concentrations, defined as ratios of the calculated metabolite concentrations relative to creatine (Cr) concentration, were compared between bilateral normal testes using Mann-Whitney U test. 1H-MRS allowed the detection of certain testicular metabolites, including total choline, Cr, myo-inositol, Glx, total lipids and macromolecules resonating at 0.9, 1.3 and 2.0 ppm. Normal left testis had higher median normalised concentrations of Glx (p = .002) and lactate (p = .041) compared with the normal right testis. Differences in concentrations of Glx were attributed to differences in glutamate (p = .020). Normal testes asymmetry is confirmed in this study by differences in the biochemical testicular profile, as assessed by 3.0 T 1H-MRS. Increase in levels of glutamate and lactate in normal left testis should be correlated with changes in metabolic pathways, specifically glycometabolism and amino acid metabolism.

Testicular Apparent Diffusion Coefficient and Magnetization Transfer Ratio: Can These MRI Parameters Be Used to Predict Successful Sperm Retrieval in Nonobstructive Azoospermia?

OBJECTIVE. The aim of our study was to assess if testicular apparent diffusion coefficient (ADC) and magnetization transfer ratio (MTR) can be used as MRI parameters to predict the presence of spermatozoa retrieved after microdissection testicular sperm extraction (mTESE) in men with nonobstructive azoospermia (NOA). MATERIALS AND METHODS. The study included 49 men with NOA and 45 age-matched control subjects. Participants underwent scrotal MRI between June 2013 and January 2017, 1 day before mTESE. Testicular volume (TV), ADC, and MTR were measured. NOA testes were classified as follows: group 1, testes with higher Johnsen score of ≥ 8; and group 2, testes with higher Johnsen score of < 8. Nonparametric statistical tests were used to assess differences in TV, ADC, and MTR between men with NOA and control subjects, the two NOA groups, and NOA testes with positive sperm retrieval and NOA testes with negative sperm retrieval. RESULTS. TV (p < 0.001) was reduced and both ADC (p < 0.001) and MTR (p = 0.013) were increased in NOA testes compared with normal testes. A positive correlation between higher Johnsen score and TV (p < 0.001) and a negative correlation between higher Johnsen score and both ADC (p = 0.015) and MTR (p = 0.003) were found. TV (p < 0.001) was reduced in NOA testes with failed sperm retrieval compared with NOA testes with positive sperm retrieval. On the contrary, ADC (p = 0.011) and MTR (p = 0.045) were significantly increased in NOA testes with negative sperm retrieval. CONCLUSION. On the basis of our preliminary data, TV, ADC, and MTR might represent useful MRI parameters in the workup of patients with NOA by helping to predict the presence of spermatozoa after mTESE.

Diffusion tensor imaging as an adjunct tool for the diagnosis of varicocele.

A noninvasive imaging technique providing information about testicular dysfunction in testes with varicocele would be useful. The aim is to measure the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) in testes of infertile men with varicocele and to assess interobserver agreement. Sixteen infertile men with varicocele and 14 age-matched controls underwent 1.5 T diffusion tensor imaging (DTI) MRI. Testicular ADC and FA were measured by two radiologists independently. Parametric and nonparametric statistical tests were applied to compare between the ADC and FA of testes with varicocele and normal testes. Interobserver agreement was evaluated. The interobserver variability for ADC (0.915) and FA (0.948) was very good. No differences in ADC (p = 0.294) were found between the two groups. FA was significantly lower in testes with varicocele compared to age-matched controls (p < 0.001). An optimal cut-off of FA 0.08 was found for the diagnosis of varicocele (sensitivity = 88%, specificity = 93.5%, positive predictive value = 91.6% and negative predictive value = 90.6%). Based on our results, FA is useful for the diagnosis of testes in infertile men with varicocele, with very good interobserver agreement. Therefore, DTI may be used as a noninvasive imaging tool in the work-up of varicocele.

Diffusion tensor imaging parameters in testes with nonobstructive azoospermia.

BACKGROUND: The development of noninvasive imaging parameters having the capacity to identify the population of men with nonobstructive azoospermia (NOA) where a successful sperm retrieval outcome is of great clinical significance. PURPOSE/HYPOTHESIS: To assess differences of apparent diffusion coefficient (ADC) and fractional anisotropy (FA) in NOA testes with impaired spermatogenesis and the possible association with the presence of spermatozoa after testicular sperm extraction (TESE). STUDY TYPE: Retrospective. POPULATION: Twenty NOA men (35 testes) and 21 age-matched controls (36 testes). FIELD STRENGTH/SEQUENCE: 1.5T, T1 WI-SE T2 WI-FSE FS SS-EP-DTI. ASSESSMENTS: The MRI data were analyzed by two radiologists in consensus. The average ADC and FA of testicular parenchyma was measured. NOA testes were classified as NOA with higher Johnsen score (JS) ≥8 (group 1) and JS <8 (group 2). STATISTICAL TESTS: Parametric and nonparametric statistical tests were used to compare ADC and FA between NOA groups and normal testes (group 3) and to evaluate a possible association with the presence of spermatozoa after TESE. RESULTS: Differences in ADC were found between groups 1 and 2 (P = 0.043) and groups 2 and 3 (P = 0.004), but not between groups 1 and 3 (P = 0.418). Higher values of FA were found both in NOA testes with JS ≥8 (P < 0.001) and JS <8 (P < 0.001) compared to controls. ADC (P = 0.096) and FA (P = 0.516) did not demonstrate differences in NOA testes with or without spermatozoa at TESE. DATA CONCLUSION: Both ADC and FA are increased in NOA testes compared to a normal population. ADC was proven to be a more useful diagnostic adjunct tool in the identification of the population of NOA men with foci of advanced spermatogenesis. However, DTI parameters were not predictive of sperm retrieval after TESE. LEVEL OF EVIDENCE: 4 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:1318-1325.

MRI of the scrotum: Recommendations of the ESUR Scrotal and Penile Imaging Working Group.

OBJECTIVES: The Scrotal and Penile Imaging Working Group (SPI-WG) appointed by the board of the European Society of Urogenital Radiology (ESUR) has produced recommendations for magnetic resonance imaging (MRI) of the scrotum. METHODS: The SPI-WG searched for original and review articles published before September 2016 using the Pubmed and Medline databases. Keywords used were 'magnetic resonance imaging', 'testis or testicle or testicular', 'scrotum', 'intratesticular', 'paratesticular', 'extratesticular' 'diffusion-weighted', 'dynamic MRI'. Consensus was obtained among the members of the subcommittee. The expert panel proposed recommendations using Oxford Centre for Evidence-Based Medicine 2011 Levels of Evidence. RESULTS: The recommended MRI protocol should include T1-, T2-weighted imaging, diffusion-weighted imaging and dynamic contrast-enhanced MRI. Scrotal MRI can be clinically applied for lesion characterisation (primary), including both intratesticular and paratesticular masses, differentiation between germ-cell and non-germ-cell neoplasms (evolving), characterisation of the histological type of testicular germ cell neoplasms (TGCNs, in selected cases), local staging of TGCNs (primary), acute scrotum (in selected cases), trauma (in selected cases) and undescended testes (primary). CONCLUSIONS: The ESUR SPI-WG produced this consensus paper in which the existing literature on MRI of the scrotum is reviewed. The recommendations for the optimal imaging technique and clinical indications are presented. KEY POINTS: • This report presents recommendations for magnetic resonance imaging (MRI) of the scrotum. • Imaging acquisition protocols and clinical indications are provided. • MRI is becoming established as a worthwhile second-line diagnostic tool for scrotal pathology.

Normal testes asymmetry evaluated by apparent diffusion coefficient and magnetization transfer ratio.

Background In humans, the left testis generally hangs lower than the right and the right is larger than the left. Magnetic resonance imaging (MRI) represents an important adjuvant modality in the investigation of testicular diseases. Purpose To assess if normal testes asymmetry is related to apparent diffusion coefficient (ADC) and magnetization transfer ratio (MTR). Material and Methods The normal testes from 106 men were included. Testicular volume (TV) was calculated by using the ellipsoid formula: length × width × height × 0.52. Diffusion-weighted imaging was performed using a SS EPI diffusion pulse sequence and b-values of 0 and 900 s/mm-2. Magnetization transfer imaging was obtained using a 3D GRE sequence both with and without an off-resonance radiofrequency pulse. MTR maps were obtained by the following formula: (SIo-SIm) / (SIo) × 100%, where SIo and SIm represent the signal intensity in the baseline image and that in the corresponding image acquired with an off-resonance MT pulse, respectively. The mean and standard deviation of testicular volume (TV), ADC, and MTR of both testes was calculated and compared using a paired sample t-test. Results The mean TV (mL) was greater ( P = 0.006) for the right testis (16.77 ± 4.84) compared to the left (15.97 ± 4.45). ADC of the right testis (1.09 ± 0.12 × 10 - 3 mm2 s-1) was not different ( P = 0.064) from that of the left testis (1.07 ± 0.12 × 10-3 mm2 s-1). Differences ( P = 0.032) were observed between MTR of the right (46.6 ± 2.1%) and left testis (46.0 ± 2.2%). Conclusion The reported differences in paired testes size was confirmed, introducing a possible relationship with structural and functional asymmetry of normal testes, based on MTR.

MR Spectra of Normal Adult Testes and Variations with Age: Preliminary Observations.

OBJECTIVES: The aim was to determine the proton MR (1H-MR) spectra of normal adult testes and variations with age. METHODS: Forty-one MR spectra of normal testes, including 16 testes from men aged 20-39 years (group I) and 25 testes from men aged 40-69 years (group II), were analyzed. A single-voxel point-resolved spectroscopy sequence (PRESS), with TR/TE: 2000/25 ms was used. The volume of interest was placed to include the majority of normal testicular parenchyma. Association between normalized metabolite concentrations, defined as ratios of the calculated metabolite concentrations relative to creatine concentration, and age was assessed. RESULTS: Quantified metabolites of the spectra were choline (Cho), creatine (Cr), myo-inositol (mI), scyllo-inositol, taurine, lactate, GLx compound, glucose, lipids, and macromolecules resonating at 0.9 ppm (LM09), around 20 ppm (LM20), and at 13 ppm (LM13). Most prominent peaks were Cho, Cr, mI, and lipids. A weak negative correlation between mI and age (P = 0.015) was observed. Higher normalized concentrations of Cho (P = 0.03), mI (P = 0.08), and LM13 (P = 0.05) were found in group I than in group II. CONCLUSIONS: 1H-MR spectra of a normal adult testis showed several metabolite peaks. A decrease of levels of Cho, mI, and LM13 was observed with advancing age. KEY POINTS: • Single-voxel PRESS MRS of a normal testis is feasible. • 1H-MR spectra of a normal testis showed several metabolite peaks. • Most prominent peaks were Cho, Cr, mI, and lipids. • A decrease of Cho, mI, and LM13 was seen with advancing age.

Magnetization transfer imaging of normal and abnormal testis: preliminary results.

OBJECTIVES: The aim was to determine the magnetization transfer ratio (MTR) of normal testes, possible variations with age and to assess the feasibility of MTR in characterizing various testicular lesions. METHODS: Eighty-six men were included. A three-dimensional gradient-echo MT sequence was performed, with/without an on-resonance binomial prepulse. MTR was calculated as: (SIo-SIm)/(SIo) × 100 %, where SIm and SIo refers to signal intensities with and without the saturation pulse, respectively. Subjects were classified as: group 1, 20-39 years; group 2, 40-65 years; and group 3, older than 65 years of age. Analysis of variance (ANOVA) followed by the least significant difference test was used to assess variations of MTR with age. Comparison between the MTR of normal testis, malignant and benign testicular lesions was performed using independent-samples t testing. RESULTS: ANOVA revealed differences of MTR between age groups (F = 7.51, P = 0.001). Significant differences between groups 1, 2 (P = 0.011) and 1, 3 (P < 0.001) were found, but not between 2, 3 (P = 0.082). The MTR (in percent) of testicular carcinomas was 55.0 ± 3.2, significantly higher than that of benign lesions (50.3 ± 4.0, P = 0.02) and of normal testes (47.4 ± 2.2, P < 0.001). CONCLUSIONS: MTR of normal testes decreases with age. MTR might be helpful in the diagnostic work-up of testicular lesions. KEY POINTS: MTR of normal testes shows age-related changes. Testicular carcinomas have high MTR values. MTR may be useful in the diagnostic work-up of testicular lesions.

Incidentally detected non-palpable testicular tumours in adults at scrotal ultrasound: impact of radiological findings on management Radiologic review and recommendations of the ESUR scrotal imaging subcommittee.

OBJECTIVES: The increasing detection of small testicular lesions by ultrasound (US) in adults can lead to unnecessary orchiectomies. This article describes their nature, reviews the available literature on this subject and illustrates some classical lesions. We also suggest recommendations to help characterization and management. METHODS: The ESUR scrotal imaging subcommittee searched for original and review articles published before May 2015 using the Pubmed and Medline databases. Key words used were 'testicular ultrasound', 'contrast-enhanced sonography', 'sonoelastography', 'magnetic resonance imaging', 'testis-sparing surgery', 'testis imaging', 'Leydig cell tumour', 'testicular cyst'. Consensus was obtained amongst the members of the subcommittee, urologist and medical oncologist. RESULTS: Simple cysts are frequent and benign, and do not require follow up or surgery. Incidentally discovered small solid testicular lesions detected are benign in up to 80 %, with Leydig cell tumours being the most frequent. However, the presence of microliths, macrocalcifications and hypoechoic areas surrounding the nodule are findings suggestive of malignant disease. CONCLUSION: Asymptomatic small testicular lesions found on ultrasound are mainly benign, but findings such as microliths or hypoechoic regions surrounding the nodules may indicate malignancy. Colour Doppler US remains the basic examination for characterization. The role of newer imaging modalities in characterization is evolving. KEY POINTS: • Characterization of testicular lesions is primarily based on US examination. • The role of MRI, sonoelastography, contrast-enhanced ultrasound is evolving. • Most small non-palpable testicular lesions seen on ultrasound are benign simple cysts. • Leydig cell tumours are the most frequent benign lesions. • Associated findings like microliths or hypoechoic regions may indicate malignancy.