Undescended Testes in Adults: Clinical Significance of Resistive Index Values of the Testicular Artery Measured by Doppler Ultrasound as a Predictor of Testicular Histology

The Use of Doppler Ultrasonography in the Examination of Testicles in Dogs

Doppler ultrasonography is method suitable for observing and measuring the blood supply of many organs. Its principle is the change in the frequency of wave blood that moves with respect to the source of the wave (probe). In a testicular examination, the use of Doppler can also be very useful for detecting abnormalities or pathological conditions. The aim is just to characterize the flow in arteria testicularis in clinically healthy dogs aged 1-5 years. Twelve dogs were included in the study, of which 6 were rough collies weighing approximately 23 kg and 6 were standard dachshunds weighing approximately 9 kg. The pulsatility index (PI) and resistance index (RI) of a.testicularis, as well as the dimensions of the testicles - height and depth, were assessed by ultrasonographic examination using the ALOKA ProSound Alpha 6 ultrasonographic device (Hitachi-Aloka, Japan). The statistical evaluation of the results shows that the differences between the averages of both measurements of PI and RI indices are highly significant, so the weight of the individual had a high effect on the measured values of PI and RI indices. The depth of the testicles was also directly related to the increasing values of PI and RI indices and to the weight of the dogs, in contrast to their height, which did not show any statistical significance in this respect. The measured values and findings may in the future also serve as a basis for determining reference values in testicular ultrasonography according to the weight of dogs, which may be beneficial in clinical status assessment, diagnosis of various pathological conditions, or predicting spermatogenesis and fertility of the individuals.

The clinical application of ultrasonography with superb microvascular imaging-a review

Superb microvascular imaging (SMI) is among the latest doppler ultrasound methods. It uses an advanced clutter filter to eliminate artifacts caused by breathing, movement and retains the low-speed blood signals in microvessels. The great advantage of SMI is that it can intuitively detect very slow blood signals in microvessels, providing clinicians with more significant information about flow distribution in the target area. Therefore, it is speculated that SMI has important application value. The purpose of this article is to outline the application of SMI in different parts of the body.

Spectral Doppler sonography: a noninvasive method for predicting dyspermia

OBJECTIVES

Sonography is a noninvasive, office-based diagnostic tool often used for evaluation of subfertile men. Previous studies have suggested that a resistive index (RI) greater than 0.6 is associated with impaired spermatogenesis. We sought to validate this threshold in a urologic patient population presenting for infertility evaluation.

METHODS

We retrospectively reviewed 99 consecutive patients seen for nonobstructive male infertility at our institution. Patient demographics, semen analysis parameters, hormone profiles, lipid profiles, and penile and scrotal sonographic measurements were recorded. The RI was calculated from measurements of the peak systolic velocity and end-diastolic velocity. Ninety-one patients fit the inclusion criteria and were subsequently divided into 2 groups based on RI: group 1 with RI values of 0.6 or less (n = 49) and group 2 with RI values greater than 0.6 (n = 42).

RESULTS

Variables that were significantly different between the groups included age, total sperm count, percent motile sperm, total motile sperm, follicle-stimulating hormone, high-density lipoprotein, and testis volume. On the other hand, body mass index, forward progression, World Health Organization score, total testosterone, free testosterone, estradiol, total cholesterol, low-density lipoprotein, and triglycerides were not significantly different between the groups. A receiver operating characteristic curve revealed an area under the curve of 0.64 (confidence interval, 0.52-0.75; P = .025). At the threshold of greater than 0.6, the RI had specificity of 63.27% and a 1.56 likelihood ratio to predict total motile sperm less than 20 × 10(6) at spermatogenesis.

CONCLUSIONS

An intratesticular RI greater than 0.6 is associated with impaired spermatogenesis. This finding supports the use of testicular spectral Doppler sonography as a noninvasive tool for evaluation of testicular function.

Evaluation of testicular artery blood flow by Doppler ultrasonography as a predictor of spermatogenesis in the dog

The present study examines the relationship between reproductive and seminal characteristic with blood flow supply of the testis in male dogs by means of Doppler ultrasonography. Five male dogs were subject to a clinical examination, blood sampling, B-Mode and Doppler ultrasonography of the testis, semen evaluation at collections and after storage at 4°C for 24, 48 and 72 h in three replicates 30 days apart. Peak Systolic Velocity was positively correlated with testicular volume and negatively with live sperm at collections and after 24h. A negative correlation existed between Resistive Index and Pulsatility Index with total and progressive motility at collections and also after 24, 48 and 72 h. Resistive Index and Pulsatility Index were also negatively correlated with the percentage of membrane intact sperms with curled tails at collections while the latter was positively correlated with End Diastolic Velocity. Moreover, positive linear correlations of weight with bilateral testicular volume and total sperm concentration and also between age and abnormal sperm at collections and after 24h were established. The results suggest that the Resistive Index and Pulsatility Index seem to be potential markers of seminal quality in dogs.

High-frequency color Doppler ultrasonography of the spermatic cord arteries: resistive index variation in a cohort of 51 healthy men

OBJECTIVE

The purpose of this study was to determine the normal range of Doppler ultrasonographic measurements of spermatic cord arteries in a cohort of healthy men.

METHODS

The spermatic cord arteries of 51 men were interrogated with color Doppler ultrasonography. The resistive index (RI) of each artery was measured for the entire cohort; peak systolic and end-diastolic velocity values were obtained in a smaller subgroup (n = 31). The artery with the lowest RI was labeled A; the other 2 arteries were identified as B and C.

RESULTS

Three separate arteries were identified within the spermatic cord in all individuals. The median RI values for arteries A, B, and C were 0.70 (range, 0.48-0.82), 0.84 (0.67-0.90), and 0.84 (0.72-0.92), respectively. One-way analysis of variance showed a significant difference between the mean RIs of arteries A and B (P < .0001) and arteries A and artery C (P < .0001) but not between B and C (P = .49). Peak systolic and end-diastolic velocity values differed significantly between arteries A and B (P < .0001) and arteries A and C (P < .0001) but not between B and C (P = .31). No age effect was shown for the RI measurements of the cohort.

CONCLUSIONS

Color Doppler ultrasonography enables the objective quantification of Doppler measurements of arteries within the spermatic cord. Knowledge of the normal range of Doppler measurements for spermatic cord arteries that supply the testes may be a useful adjunct to the assessment of the testes.

Color Doppler ultrasound evaluation of testicular blood flow in stallions

The objectives of this study were to evaluate the potential use of color Doppler ultrasound to characterize blood flow to the stallion testis, and to establish reference values for Doppler measures of blood flow in the testicular artery of the stallion. Both testes from each of 52 horses were examined using a pulsed-wave color Doppler ultrasound with a sector array 5/7.5 MHz transducer with a 1mm gate setting. Peak systolic velocity (PSV), end diastolic velocity (EDV), resistive index (RI), and pulsatility index (PI) of the testicular artery were measured in each of two locations, the convoluted aspect (spermatic cord) and the marginal aspect of the artery (on the epididymal edge of testis). We found that: (1) all measures were obtainable; (2) except for EDV, the majority of the measures were higher at the cord location than at the marginal aspect of the artery (P < 0.05); and (3) measures for left and right testes were similar (P > 0.10). Resulting measures from 41 of these stallions (82 testes) that appeared free of testicular pathology provide useful reference values for clinical evaluation. Evaluation of 11 cases with testicular pathology suggested further investigation of possible effects of these various conditions on testicular blood flow and testicular function.

Spermatogenesis and spectral echo-colour Doppler traces from the main testicular artery

OBJECTIVE

To assess whether the peak systolic velocity (PSV), end-diastolic velocity (EDV) and resistive index (RI) of testicular arteries may be useful in distinguishing the various causes of dyspermia when compared with follicle-stimulating hormone (FSH) and testicular volume.

PATIENTS, SUBJECTS AND METHODS

The study included nine men with obstructive and 20 with unobstruc-tive azoospermia, 17 with oligoasthenospermia and clinical varicoceles, with male accessory glans inflammation (MAGI), 38 with undetermined oligoasthenospermia, 19 with MAGI, 11 with clinical varicoceles, 32 subjects with normal sperm analysis and recent paternity (fertile controls), and 15 with normal sperm analysis and a varicocele with recent paternity (fertile + varicoceles). Testicular volume, FSH, PSV, EDV and RI were compared among the dyspermic and/or control groups using analysis of variance.

RESULTS

The PSV and RI were useful for identifying the different groups of patients, while EDV, FSH and testicular volume were not. Men with varicoceles, varicoceles + MAGI or fertile with varicoceles had the highest PSV and RI; fertile controls, those with obstructive azoospermia and MAGI had similar PSVs and RIs, those with unexplained oligoasthenospermia had a significantly lower PSV and RI, and men with unobstructive azoospermia had the lowest PSV and RI.

CONCLUSIONS

The RI and PSV are reliable indicators for routine clinical use to identify infertile/dyspermic men, while EDV, FSH and testicular volume are not. The RI and especially PSV clearly differentiated obstructive from unobstructive azoospermia.