Surprising interobserver and intra-observer variability in pediatric testicular ultrasound volumes

Size matters: Total testicular volume predicts sperm count in Tanner V varicocele patients

INTRODUCTION

It is known the prevalence of varicoceles in adolescent men is 14-29% but there is debate surrounding implications on fertility. As obtaining a semen analysis (SA) may be challenging, there is need for objective tests as measures of fecundity. Our aim was to investigate the relationship between testicular volume differential (TVD), varicocele grade, and total testicular volume (TTV) on seminal parameters including total motile sperm count (TMSC).

MATERIALS AND METHODS

We conducted a retrospective single-center chart review over 14 years of 486 Tanner V adolescent males. Three hundred and four met inclusion of palpable, non-operated left-sided varicocele who underwent at least one SA and ultrasound. Abnormal TMSC was defined by World Health Organization 2010 criteria for minimal reference ranges. Multivariate logistic regression, receiver operating characteristic analysis with Youden J-statistic and descriptive statistics were performed.

RESULTS

Three hundred and four Tanner V adolescents with median age of 18.0 years (18.0-19.0), median TTV of 34.5 cc (28.9, 40.2) and median TMSC of 62.5 million/ejaculate (25.4, 123.4) were evaluated. TTV cutoff of 29.5 cc was found to predict TMSC of <9 million/ejaculate with negative predictive value of 96.2% and odds ratio of 6.08 ([2.13-17.42], p < 0.001). TVD greater than 20% did not reach statistical significance with an odds ratio of 1.66 ([0.41-6.62], p = 0.50).

DISCUSSION

In clinical practice, each patient will need to have an individualized plan. Based on our data, for older adolescents (17 or 18 years) with varicocele and an abnormal TTV, clinicians may have a lower threshold for advising SA, and if unable to obtain, surgical intervention and/or closer surveillance should be stressed. Patients should be informed of their six-fold increase in abnormal SA. Patients with normal TTV should be advised they are at lower risk of having abnormal SA. Younger patients with varicocele and an initial TVD>20%, should be followed closely but intervention delayed until 17 or 18 to better assess TTV. The importance of trending patient data should be emphasized as a single measurement has low predictive value for developing adolescents. Limitations of our study include a retrospective design and the lack of uniform correlation between adolescent SA and paternity.

CONCLUSIONS

Total testicular volume less than 29.5 cc increased odds of abnormal semen analysis by over six times and had a negative predictive value of 96.2%. Ultrasound results may be useful for risk stratification and counselling on appropriateness of surgical intervention.

Intra- and Interobserver Variability in Ultrasound Measurement of Testicular Volumes in Pubertal Boys

Accurate measurement of testicular volume (TV) in boys is an important tool in clinical practice, e.g., in varicocele treatment. This study aims to assess the degree of intra- and interobserver variability of testicular volume measurements. In a prospective study, boys between 11 and 17 years of age without testicular pathology were enrolled. Testicular ultrasound was performed by three investigators (A: pediatric radiologist; B: pediatric surgery/urology resident; C: pediatric urologist). Intraobserver variability was calculated in investigators B and C and interobserver variability between all three investigators. A total of 30 boys were enrolled. Mean intraobserver variability in both observers was +0.3% with a range of -39.6 to 51.5%. The proportion of measurements with a difference >20% was 18.6%. The mean interobserver variability was -1.0% (range: -74.1% to 62.8%). The overall proportion of measurements with a difference >20% was 35%. A lower testicular size of < 4 mL showed a significantly higher rate of >20% difference in both the intraobserver group (31.1% vs. 14.4%; p = 0.035) and the interobserver group (63.2% vs. 26.2%; p = 0.000031). Furthermore, the rate of >20% difference was significantly lower in obese compared to non-obese patients in both the intraobserver (2.8% vs. 22.4%; p = 0.0084) and the interobserver group (24% vs. 40.8%, p = 0.0427). Both intraobserver and interobserver variability in ultrasound-based TV measurements in pubertal boys contain a relevant degree of uncertainty that renders them unsuitable for individualized follow-up care. At the cohort level, however, mean differences in ultrasound-based TV measurements are low enough to make ultrasound comparisons reasonable.

Ultrasound assessment of testicular volume - An interobserver variability study

BACKGROUND

Ultrasonography measurement of the testicles and subsequent calculation of the testicular volume is recommended as a part of a standard scrotal ultrasound examination. The interobserver variability of testicular volume measurement has implications for surgical recommendations. Therefore, this study aimed to investigate the interobserver variability in the measurement of testicular volume.

METHODS

Interobserver variability was established by comparing testicular measurements performed by two observers on the same patient during the same clinical appointment. The observers were blinded to each other's measurements. Testicular volume was calculated using the Lambert formula: length x width x height x 0.71. A total of three observers, A, B and C, participated in the study. The observers had between 4 to 20 years' experience with scrotal ultrasound examinations.

RESULTS

In total, 24 patients' were included (48 testicles). The patient´s mean age was 43 years (range 19-75 years). The overall mean right testicular volume was 19.8 ml (range 7.3-31.6 ml), and the left was 20.1 ml (range 7.1-36.1 ml). The interclass correlation coefficient (ICC) between observer A and B was excellent (ICC= 0.98, CI:0.92-0.99), between observer A and C, was excellent (ICC=0.91, CI: 0.77-0.97) and between B and C good (ICC=0.82, CI:0.51-0.93).

CONCLUSION

Variability in estimating testicular volume is low, with interobserver agreement ranging from good to excellent. Ultrasound provides a highly reproducible tool to determine testicular volume.

Semiautomated Software to Improve Stability and Reduce Operator-Induced Variation in Vascular Ultrasound Speckle Tracking

OBJECTIVES

Ultrasound is useful in predicting arteriovenous fistula (AVF) maturation, which is essential for hemodialysis in end-stage renal disease patients. We developed ultrasound software that measures circumferential vessel wall strain (distensibility) using conventional ultrasound Digital Imaging and Communications in Medicine (DICOM) data. We evaluated user-induced variability in measurement of arterial wall distensibility and upon finding considerable variation we developed and tested 2 methods for semiautomated measurement.

METHODS

Ultrasound scanning of arteries of 10 subjects scheduled for AVF surgery were performed. The top and bottom of the vessel wall were tracked using the Kanade-Lucas-Tomasi (KLT) feature-tracking algorithm over the stack of images in the DICOM cine loops. The wall distensibility was calculated from the change of vessel diameter over time. Two semiautomated methods were used for comparison.

RESULTS

The location of points selected by users for the cine loops varied significantly, with a maximum spread of up to 120 pixels (7.8 mm) for the top and up to 140 pixels (9.1 mm) for the bottom of the vessel wall. This variation in users' point selection contributed to the variation in distensibility measurements (ranging from 5.63 to 41.04%). Both semiautomated methods substantially reduced variation and were highly correlated with the median distensibility values obtained by the 10 users.

CONCLUSIONS

Minimizing user-induced variation by standardizing point selection will increase reproducibility and reliability of distensibility measurements. Our recent semiautomated software may help expand use in clinical studies to better understand the role of vascular wall compliance in predicting the maturation of fistulas.

IHC_Tool: An open-source Fiji procedure for quantitative evaluation of cross sections of testicular explants

Immunohistochemical analysis is a routine procedure for clinical and research studies in male fertility. However, most of the interpretations remain subjective and time-consuming, with inherent intra- and inter-observer variability. Given the prognostic and research implications of testicular assessment, a more objective and less time-consuming method is required. In the current study, we used in vitro matured pre-pubertal murine testes as a model. The main objective was to develop an affordable automated digital immunohistochemistry image analysis tool for an unbiased and quantitative assessment of testicular tissue sections. Testicular explants were fixed, cut, and stained for specific germ cell markers. The classical manual counting procedure was evaluated. Background and noise were reduced on brightfield images. Photomicrographs were stitched (Background_Elimination_Stitching) to create high-quality images. Two procedures were evaluated (IHC_Tool and Stained_Nuclear_Area); then a procedure (Necrotic_Area_Elimination) allowing withdrawal of the necrotic area observed after culture was assessed. Finally, the number of stained nuclei in the unaltered tissue area was extracted. The automated IHC_Tool procedure with images saved as TIFF at a ×200 magnification allowed the most rigorous cell quantification. IHC_Tool developed for testicular sample analysis can be used for various types of tissues. We foresee that this method will minimize inter-observer variations across laboratories and will be helpful for clinical trials and translational initiatives.

Three‑Dimensional Ultrasonography in Preoperative and Postoperative Volume Assessment of the Undescended Testicle

BACKGROUND Ultrasound (US) is the preferred imaging method for cryptorchidism, but most guidelines indicate that its value is questionable. The aim of this study was to evaluate the clinical value of ultrasonic mobility and testicular atrophy index (TAI) based on three‑dimensional US (3DUS) in preoperative and postoperative assessment of the undescended testis. MATERIAL AND METHODS Data from 158 children with unilateral extraperitoneal cryptorchidism were collected and their diagnoses were surgically confirmed. They were divided into different age groups and into 2 ultrasonic mobility groups: the mobile group (MG) and the restricted group (RG). Differences in sonographic characteristics between different groups were compared. Three-dimensional ultrasound performed with virtual organ computer-aided analysis (VOCAL) was used to determined preoperative and postoperative TAI and the reliability of TAI was analyzed. RESULTS Measurement of testicular volume with the VOCAL method was significantly more reliable than that done with the two-dimensional Lambert method. In all age groups, preoperative testicular volumes were smaller than that in the contralateral scrotal testis and postoperatively, they increased steadily. Both preoperative and postoperative TAI were higher in the RG than in the MG. In the MG, postoperative TAI decreased significantly in all age groups. In the RG, in contrast, effective volume growth was only achieved in patients who had undergone surgery before they reached age 1 year. CONCLUSIONS TAI values determined with 3DUS using the VOCAL technique objectively reflect recovery of testicular volume following surgery for undescended testicle. Ultrasonic mobility evaluation is beneficial for clinical management of the condition.