Objective To assess the usefulness of ultra-sound, computerized tomography (CT), magnetic resonance imaging (MRI) and laparoscopy in the diagnosis of the location of undescended testes.
Patients and Methods Thirty-six male patients with undescended testes constitute the ma-terial of this study. The mean age of the patients was 8 ± 1.1 years. Thirteen cases were right-sided, 16 left-sided and 7 cases presented with bilateral undescended tes-tes making a total of 43 undescended testes. Of these, 34 testes were impalpable and 9 palpable in the inguinal canal. Clinical examination including ultrasound, CT, MRI and laparoscopy was done for all patients. One-stage laparoscopic orchidopexy was performed.
Results Ultrasound identified 10 true positive testes, 9 of them were in the inguinal canal and one at the internal ring. None of the intra-abdominal testes could be detected by ultrasound. Specificity and sensitivity of ultrasound were 62.5% and 11%, respec-tively. The overall accuracy of ultrasound was 30%. On the other hand, CT identified 18 true positive testes and 3 true negative testes with a specificity and sensitivity of 72% and 16.6%, respectively. The overall accuracy of CT was 49%. MRI identified 31 true positive testes and 3 true negative testes with a specificity and sensitivity of 94% and 30%, respectively. The overall

accuracy of MRI was 79%. Laparoscopy identified 25 testes located intra-abdo-minally. The vas and vessels were seen entering the inguinal canal in 16 cases, 15 of them were found in the canal and in one case they ended blindly. Intra-abdominal blind-ended vas and vessels were detected in two cases. The overall accuracy of laparoscopy was found to be 100% as confirmed by surgery.
Conclusion While both ultrasound and CT can reliably detect undescended testes located in the inguinal canal, CT is superior for the detection of abdominal testes. MRI may be useful in the evaluation of non-palpable testes. However, failure to localize a testis by MRI should not rule out laparoscopic exploration. Laparoscopy is the most accurate method in the diagnosis of undescended testes. Whenever MRI and/or laparoscopy are available, there is no need for CT scan, especially in children where diagnostic imaging is not routinely needed. Surgery is usually necessary and laparo-scopy can be performed with relative ease. However, in adult patients or obese child-ren, radiographic imaging prior to surgery may help to identify the location of the testis and allow surgery to be more appropriately planned.
Key Words ultrasound, MRI, CT, laparoscopy, cryptorchid testis

INTRODUCTION

Cryptorchidism is a common problem in paediatric surgical practic. The truly impalpable testis presents a difficult problem. These testes may be in an ectopic site, intracanalicular or intra-abdominal. In a proportion of cases the testis may be absent1. Recent publications allude to an apparent increased incidence of cryptochidism in recent years. Chilvers et al. reported that between 1962 and 1981 the rate

Table 1: The Side of Undescended Testes

Calculated X2=3.50NS, TabulatedX052=5.99

Even though the incidence of crypt-orchidism may have only slightly altered over the years, the frequency of orchiopexies has increased threefold4. This changed approach to cryptorchidism is due to a better understand-ing of the adverse histologic changes that develop quite early and rapidly in primary and secondary cryptorchid testes5.

The present study was designed to assess the usefulness of ultrasound (US), compute-rized tomography (CT), magnetic resonance imaging (MRI) and laparoscopy in the dia-gnosis of the location of undescended testes, and to determine the most accurate and least invasive diagnostic modality of treating crypt-orchid testes.

PATIENTS AND METHODS

Thirty-six male patients with undescended testes constitute the material of this study carried out at the urology department, Zagazig University Hospital, Zagazig University. The mean age of the patients was 8+1.1 years. There were 13 cases with right-sided and 16 cases with left-sided undescended testes. The remaining 7 cases presented with bilateral undescended testes making a total of 43 undescended testes; of these, 34 were found to be impalpable, while the remaining 9 testes were palpable in the inguinal canal.

All patients of the study were subjected to history and clinical examination, laboratory investigations and radiological evaluation in-cluding:

(1) Ultrasonography using the Toshiba sono layer-SSA-270 A with 7.5 MHz fre-quency transducer ,

(2) Computed tomography (CT) using CT (GE SYTEC SRI) with contrast. Slices of 5 mm thickness were obtained from the inferior public ramous through the anterior superior iliac spine. Additional scans up to the level of the iliac crest were sometimes necessary when the testis could not be located on the initial scans.

(3) Magnetic resonance imaging studies were done for all cases using GE (signa contour) 0.5 TESLA Radio frequency. A multisection, spin-echo (SE) imaging technique was used in all patients. T1 predominant images were obtained with a repetition time (TR) of 500 msec and echo-times (TE) of 20 mesec. T2 predominant images were obtained with a TR of 3000-4000 msec and a TE of 80-90 msec. Imaging was performed in the transverse plane with both T1 and T2 predominant sequences from the base of the scrotum to the iliac crest to assess the entire course of the spermatic cord. The imaging was repeated in the coronal plane with a T2-predominant sequence from the posterior aspect of the scrotum to the anterior abdominal wall.

Laparoscopic examination was performed in all cases. Under general anaesthesia a last attempt was made to feel the missing testis to be absolutely sure that the testis was impalpable. The patient’s bladder was emptied by catheterization. Laparoscopy was started by insufflating the abdomen with carbon dioxide through a Verres needle that was inserted just below the umbilicus. When the maximum intra-abdominal pressure was reached, a 6 mm in-cision was made in the lower edge of the umbilicus and deepened vertically to incise the linea alba. This incision was gently stretched with a haemostat to ensure an easy and gentle passage of a 5 mm trocar with cannula into the peritoneal cavity. The incisional edges were tented with towel clips to prevent damage to the abdominal contents. Once the trocar and cannula were introduced into the peritoneal cavity, the trocar was removed and the 0o lens was passed through the cannula. One-stage laparoscopic orchidopexy was performed

Laparoscopy was considered technically successful when a pneumoperitoneum was obtained and systematic inspection could be completed.

.

Fig. 1: CT scanning showing the left testis in the inguinal canal

Table 2: Ultrasonic Findings According to the Side of the Undescended Testis

Statistical analysis was achieved using chi-square and t-tests6.
RESULTS

The mean age of the 36 patients included in the study was 8+1.1 years with an insignificant relationship between the age and the undes-cended testes.

Clinical examination revealed that in 16 boys the undescended testis was on the left side (44.5%), while it was on the right side in

Table 4: MRI Findings According to the Side of Undescended Testis

It is evident that 25 testes were detected by CT scanning (Fig.1). On exploration 18 testes were proved to be truly present with 7 false positive data. This resulted in a specificity rate of 72%. On the other hand, 18 testes could not be identified by CT on exploration. Three tes-tes were truly absent with 15 false negative re-sults leading to a sensitivity rate of 16.6% for CT (Table 3).

Our results revealed that 33 testes were detected by MRI. Thirty-one testes were prov-ed to be truly present on exploration (Fig.2) with two false positive data. This results in a specificity rate of 94%. On the other hand, 10 testes were not detected by MRI. Only 3 of them were truly absent on exploration leading to a sensitivity rate of 30% for MRI (Table 4).

Out of the 43 undescended testes, 25 were identified by laparoscopy to be located intra-abdominally. The vas and vessels were seen entering the inguinal canal in 16 instances, 15 of them were found in the canal, while in the remaining case the vas and vessels ended blindly intra-pelvic. Intra-abdominal blind-ended vas and vessels were detected by laparoscopy in two cases (Table 5).

In all cases, the laparoscopic findings were confirmed by surgery.

Fig. 2: MRI axial T2 WI showing intra-abdominal left testis


Table 3: CT Findings According to the Side of the Undescended Testis

13 (36%). Seven patients had bilateral undes-cended testes (19.5%). Out of the 43 testes, 34 testes were found to be impalpable and the remaining 9 testes were palpable in the inguinal canal. The statistical analysis of these data showed an insignificant relationship between the undescended testis on one hand and the side of undescent or bilaterality on the other hand (Table 1).

Ultrasonography showed 16 out of 43 un-descended testes to be positive, however only 10 were truly positive; 9 were found in the inguinal canal and one was found at the internal inguinal ring. None of the intra-

Table 5: Laparoscopic Findings According to the Side of Undescended Testis

Exploration showed that out of 43 testes studied, 25 were found in an intra-abdominal location. Thirteen (30%) were truly intra-abdominal, while 12 (28%) were found at the internal inguinal ring and 15 (35%) were found in the inguinal canal. Three testes (7%) were found to be vanished.

The data in Table 6 show a comparison of the specificity, sensitivity and accuracy of US, CT, MRI and laparoscopy as different dia-gnostic modalities for undescended testes. The results of the overall accuracy of these diagnostic modalities were found to be 30% for US, 49% for CT, 79% for MRI and 100% for laparoscopy. It is of interest to mention that the difference between the accuracy of US and CT did not reach the level of significance, while the accuracy of MRI exceeded significantly the accuracy of both US and CT. It was, however, significantly lower than the accuracy of laparoscopy.

DISCUSSION

Cryptorchidism is one of the most common genital anomalies in boys. The incidence of cryptorchidism is slightly less than 1% at the age of one year7. Most undescended testicles are palpable, but a significant number are non-palpable for varied reasons, and these re-present a major controversial issue as to both diagnosis and management. Different dia-gnostic modalities, i.e. US, CT, testicular arteriography, venography, radionuclide scan-ning, MRI, provocative hormonal testes and laparoscopy have been used with varying success to locate the undescended testes8.

An overall analysis of our results showed that ultrasonography was the prime examina-tion modality in an attempt to localize the undescended testis. Out of 36 patients with 43 undescended testes, ultrasonography correctly localised 13 testes (10 positive and 3 negative) with an accuracy rate of 30%. None of the intra-abdominal testes could be identified by ultrasound. These results agree with the results of Mardrazo et al.9 who successfully localized undescended testes in the inguinal canal, but were not able to show abdominal or pelvic maldescended testes by sonography. The abdominal cryptorchid testis often is not detectable on ultrasound except when located just proximally to the internal ring of the inguinal canal8. The cause of failure may be due to the high location of the intra-abdominal testis and the small size of the testis which may, thus, not be distinguished from the surrounding structures10. These results were in agreement with our findings.

In the present study, CT scanning yielded better results than those obtained with US. CT identified 25 testes. Only 18 of them were truly present on exploration with 7 false positive results leading to a specificity rate of 72%. On CT 18 testes were absent, however, only 3 proved to be truly absent, while 15 testes proved to be falsely absent. Most of them were intra-abdominal. Thus, the sensitivity rate was 16.6% with an overall accuracy rate of 49%.It can be concluded that CT yields better results in localizing abdominal undescended testes than ultrasound. In this respect, Hrebinko and Bellinger11 reported that CT correlated in only 4 of 12 (33%) which is in agreement with our findings. On the other hand, Wolverson et al12 suggested that CT be used as a diagnostic tool, as in their study it correctly diagnosed 22 undescended testes out of 23, with one false negative result. Our findings are not as favourable as their overall accuracy results of CT due to the fact that in most cases of this

demonstrate a testis, laparoscopy was per-formed. All cases were verified by operative exploration of the inguinal region. MRI demonstrated 10 inguinal and abdominal testes, while it revealed no testis in 12 boys. When laparoscopy was performed, presser-vable testes could be demonstrated in 8 of 12 patients in whom no testes had been visible on MRI. The correct positive rate was 100%, which is the same like in our results. Chui and Jacobsen15 did a study on 16 patients with 20 non-palpable testes aiming at evaluating the role of laparoscopy in the localization of non-palpable undescended testes. Fifteen non-palpable testes were intra-abdominal, 3 had inguinal testicular remnants and 2 had vanished. They confirmed the safety and efficacy of laparoscopy in the evaluation of non-palpable testes. The same results were obtained by Cohen et al.16 and Jordan17 who recognized laparoscopy to be a reliable tool in demonstrating the abdominal testis which at the same time allows mobilization of the undescended testis for orchiopexy or for or-chiectomy of an atrophic or hypoplastic testis.

Finally, the analysis of the data obtained from our results revealed that while CT is as accurate as ultrasound in the localization of testes in the inguinal canal, it is superior in the detection of abdominal testes. MRI is highly accurate in localizing abdominal or inguinal undescended testes. Its failure should, how-ever, not rule out laparoscopic exploration. Laparaoscopy is not only a safe and reliable method in diagnosing the presence or absence of a undescended testes but also obviates the need for further surgical intervention, if no spermatic vessels are visualized in the abdomen with a blind-ending vas or a vas entering the inguinal canal. Whenever MRI and/or laparoscopy are available, there is no need for CT scan, especially in children in whom diagnostic imaging is not routinely needed for the evaluation of non-palpable testes. In these patients, surgery is usually necessary and laparoscopy can be performed with relative ease. However, in adult patients or obese children, radiographic imaging prior to surgery may help to identify the location of the testis and allow surgery to be planned more appropriately.

REFERENCES

1. Storey DW, Mackinon AW. Laparoscopy and the undescended testis. J Ped Surg 1992, 27:89.

study the testes were located either in the inguinal canal or below the external inguinal ring.

When using MRI in the evaluation of patients with non-palpable testes, we found a specificity rate of 94% and a sensitivity rate of 30% with an overall accuracy of 79%. Laparoscopic exploration revealed that most of the false negative results were found in high intra-abdominal testes. These results differ from the results of Miyano et al.13. In their study on 17 boys the non-palpable testes were correctly identified preoperatively by MRI in 15 out of the 17 patients with highly accurate results. This may on one hand be due to the small number of patients in the study carried out by Miyano et al, and on the other due to the fact that in the majority of our patients the undescended testis was located in the inguinal canal or was completely absent. In summary, MRI may be useful in the evaluation of most young children with non-palpable testes, enabling the treating surgeon to plan orchio-pexy on the basis of the MRI findings. How-ever, MRI currently is not sensitive enough to completely exclude the presence of a non-palpable testis; therefore, failure to localize a testis by MRI should not rule out laparoscopic exploration.

Laparoscopy in this study accurately identi-fied the site of the undescended testis. Twenty-five testes were located intra-abdominally. The vas and vessels were seen entering the internal ring in 16 instances. On inguinal ex-ploration, one of them was found to end blindly in the canal. Vanishing testis was reported in two cases with intra-abdominal blind-ended vessels and vas. So, the accuracy rate of laparoscopy was found to be 100%. Seimar et al.14 demonstrated the accuracy of laparoscopy as a diagnostic tool in a study on 22 boys with non-palpable testes. All cases were subjected to MRI examination. When MRI failed to

2. Chilvers G, Pike MC, Foreman D. Apparent doubling of frequency of undescended testis in England-Wales in 1962-1981. Lancet 1984, 2:330.
3. Berkowitz GS, Lapinki RH, Dolgin SE. Prevalence and natural history of cryptorchidism. Ped 1993, 92:44.
4. Steeno O, Van Gurven U, Knopps J. The increase in number of orchiopexies. Cause rather than pre-vention of male infertility. Androl 1988, 20:502.
5. Atwell JD. Ascent of the testis. Fact or fiction? Br J Urol 1985, 51:474-477.
6. Steel RE, Torrie JH. Principles and procedure of statistics. New York:McGrow Hill Book Company, p. 633, 1980.
7. Kotb M, Zaki M, Bakr A. Value of MRI in localizing the undescended testis and planning surgical treatment. Egypt Journal Radiol and Nuc Med 1997, 28:33-40.
8. Nguyen HT, Cookley F, Hricak H. Cryptorchidism: Stategies in detection. Eur Radiol 1999, 9:336-343.
9. Madrazo BL, Klugo RC, Parks JA, Diloreto R. Ultrasonographic demonstration of undescended testes. Radiol 1979, 133:181-183.
10. Gibbons MD, Cormie WT, Duckett JW. Management of the abdominal undescended testicle. J Urol 1979, 122:76.
11. Hrebinko RL, Bellinger MF. The limited role of imaging techniques in managing children with undescended testes. Radiol 1983, 146:133-136.
12. Wolverson MK, Houtuin E, Heibery E, Sundaram M, Shields J. Comparison of computed tomo-graphy with high-resolution real-time ultrasound in the localization of the impalpable testis. Radiol 1983, 146:133-136.
13. Miyano T, Koboyashi H, Shimomura H, Yamataka A, Tomita T. Magnetic resonance imaging for localization of the non palpable undescended testis. J Ped Surg 1991, 26:607.
14. Siemer S, Humke U, Uder M, Hildebrandt U, Raradiakos N, Ziegle M. Diagnosis of nonpalpable testis in childhood. Comparison of MRI and laparo-scopy in a prospective study. Eur J Pediatr 2000, 10:114-118.
15. Chui CH, Jacobsen AS. Laparoscopy in the evaluation of the non-palpable undescended testes. Singapore Med J 2000, 41:206-208.
16. Cohen Z, Newman N, Kurzbart E, Kapuller V, Mares AJ. Diagnosis and therapeutic laparoscopy for non palpable testis. 3 years of experience at Soroko Medical Center. Harefuah 1999, 136:111-113.
17. Jordan GH. Children’s genitourinary laparoscopic surgery. The pro side. Urol 1994, 44:812-814.