Presentation1, radiological imaging of undescended testis.

Health &Medicine.

1. Radiological Imaging of undescended testis(Cryptorchidism). Dr/ ABD ALLAH NAZEER. MD.

2. Cryptorchidism  refers to an absence of a  testis  (or testes) in the  scrotal sac . It may refer to an undescended testis,  ectopic testis , or an atrophic or absent testis. Correct localization of the testes is essential because surgical management varies on location. Pathology The testes develop in the abdomen and at 21 weeks of gestation migrate toward the  inguinal canal  through the deep inguinal ring. The migration is complete at 30 weeks. The  gubernaculum  is the ligament which connects the testes to the scrotum. Under hormonal influence (probably testosterone), the gubernaculum contracts, and the testes descend into the scrotum. Causes/associations of undescended testes are: premature birth (birth occurs before full descent of testes) intrauterine growth restriction (IUGR) associations with smoking, alcohol intake during pregnancy androgen insensitivity syndrome congenital syndromes Prader-Willi syndrome Noonan syndrome cloacal exstrophy prune belly syndrome gestational diabetes

3. Radiographic features Ultrasound Ultrasound has 45% sensitivity, 78% specificity, and 88% accuracy for localization of an undescended testis and is more accurate than Clinical examination. lack of a testis in the scrotal sac the undescended testis is a homogeneously hypoechoic ovoid structure, similar to the contralateral testis, with an echogenic mediastinum testis the ectopic testis may be high up in the scrotum or within the inguinal canal (39%) ultrasound is limited in intra-abdominal, pelvic or retroperitoneal/ectopic testes (20%) ultrasound is also inconclusive in evaluation of the atrophic testis (41%), where it is difficult to differentiate from lymph nodes or the pars infravaginalis gubernaculi.

4. Role of computed tomography Computed tomography (CT) is infrequently used in boys with non-palpable testes as it is unreliable and carries the risk of radiation. reported similar sensitivity of CT and USG in the evaluation of non-palpable testis.

5. MRI MRI is the best cross-sectional modality to assess Cryptorchidism (replacing CT). It has a higher sensitivity than ultrasound (~90%) and a higher specificity (100 %). Coronal T1W images can show the gubernaculum testes and spermatic cord, which can be followed to locate the undescended testes. Also, an ectopic pelvic or retroperitoneal location of testes can be identified. Diffusion-weighted MRI shows the normal testes as markedly hyperintense structures, differentiating them from surrounding structures

6. MRI protocol for Intra-abdominal/Pelvic Undescended Testes Multi-element body surface coil Sequences: Coronal true fast imaging with steady-state precession through the upper abdomen; Coronal and axial T2 weighted turbo spin echo; Axial T1 weighted turbo spin echo; Additional planes as necessary 5mm contiguous sections ± intravenous hysoscine butylbromide (Buscopan; Boehringer Ingelheim, Ingelheim, Germany) or glucagon to suppress bowel motion artifact ± intravenous contrast agent (not routinely used)   Appearances of undescended testes on MRI   On MRI the undescended testis is seen as a ‘round/ovoid high signal intensity mass along the path of testicular descent parallel to the course of the gonadal vessels’ The appearances are typically intermediate signal on T1 weighted sequences and homogenous high signal on T2.

7. MRI vs. US   Abdominal scrotal ultrasound can be useful for confirming testes in an inguinal position and also for obese patients. However, in a 2011 meta-analysis it was concluded that ultrasound does not reliably localize non-palpable testes and cannot rule out intra-abdominal testes. The sensitivity was found to be 45%, with a specificity of 78%.   The sensitivity of MR is reported to be in the region of 85%. The addition of DWI sequences results in a small increase to 89.5%, with a specificity of up to 100%. When standardized by surgery the reported the accuracy of MR ranged from 42-92%, against 21-76% for ultrasound. MRI was less efficient at locating intra-abdominal vs. inguinoscrotal testes and failed to locate most atrophied testes. T2 signal varies according to the degree of atrophy, therefore testes that are non-viable are more likely to go undetected. This requires correlation at surgery to confirm an absent rather than an undetected non-viable testis with increased malignant potential.

8. Transverse scans of the right (A) and left (B) inguinal regions of a normal patient show the spermatic cord in oblique section (arrows) anteromedial to the common femoral artery (A) and vein (V). Similar sections in a patient with a right NPT reveal non visualization of the spermatic cord on the right side (C) and a normal cord (arrow) on the left side (D ).

9. Intra-abdominal testes. Sections of the lower abdomen show the location of intra-abdominal testes (arrows): Anterior (A), medial (B), and lateral (C) to the external iliac vessels; along the right side wall of the pelvis (D); and anterior to the bifurcation of the common iliac artery (E)

10. Perineal testis. Longitudinal image (A) shows the testis (arrow) in the subcutaneous plane in the perineum, posterolateral to the scrotum. Photograph (B) shows the site of the ectopic testis (arrow)

11. Ascended testis. Image of the lower abdomen (A) shows the intra-abdominal testis (arrows). Transverse (B) and (C) longitudinal sections of the inguinal region show the two loops (arrows) of the spermatic cord in the inguinal canal. Color Doppler (D) image shows the testicular artery (arrows) in the two loops of the cord, confirming the looping of the cord. Spectral Doppler images (E,F) of the testicular artery in the two loops show flow in opposite directions. Laparoscopic picture (G) shows the intra-abdominal testis with the spermatic cord (arrow) emerging out of the internal ring

12. Moving testis: Images shows the testis (arrows) in the inguinal canal (A) and in the abdomen (B ).

13. Three cases of non-descended testes. In the first case, US images show the left testis into the IC associated with a fat-containing indirect inguinal hernia(a); the right testis (b) is detected at the level of deep inguinal ring, between bowel loops. In the second (c) and third case (d), the left testis, appearing as oval hypoechoic structure - is located in the IC, close to the deep inguinal ring. 

14. Images show varying appearance of atrophic testis (arrows). Echopoor (A), echogenic (B), eggshell calcification (C), and central calcification (D). Photograph (E) of an atrophic testis removed at exploration.

15. Axial non contrast computed tomography shows cryptorchid left testis in the left inguinal canal (long white arrow) and adjacent proximal soft tissue representing twisted cord (short white arrow ).

16. (a) Coronal reformat of non contrast computed tomography shows cryptorchid left testis in the left inguinal canal (white arrow). (b and c) Serpentine twisting soft tissue density structures proximal to it representing twisted spermatic cord (white arrows ).

17. Undescended Testis in Inguinal Canal.

18.   Doppler Ultrasonography reveals a mass approximately 4.35 cm in diameter in the left inguinal canal and no flow in the center of the mass with a rim of peripheral flow. Computed tomography reveals a left Cryptorchidism with hemorrhage and infarction, and findings are consistent with a torsion of undescended testis, with suspected superimposed inflammatory process or malignant change.

19.   Malignant neoplasms developing in one of the bilateral undescended testes. A, Undescended right testis is enlarged by carcinoma (straight arrows). The tumor has metastasized to the lymph nodes (curved arrows), which are enlarged. B,  Nontumorous intraabdominal left testis (arrow) appears as a smaller, rounded structure adjacent to the bladder (B).

20. The left gonad lies in the left paracolic gutter at the level of the renal hilum (closed arrow heads) with no apparent focal lesions and a little epididymis at the tip. On the right the gonad lies against the bowel just lateral to the lower pole of the kidney (open arrow head).

21. Retrocecal Intra-abdominal Testes: An undescended right testis in a patient with raised AFP and a background of prune belly syndrome. An ovoid structure lies retrocaecally (open arrow head). This is an unusual position for a testis but vessels extend to the right renal vein.

22. Low Intra-abdominal Testes The left testis lies anterior to the left psoas muscle at the level of the left common iliac artery division (open arrow head). The right testis is present within the pelvis in a posteromedial position to the left of the external iliac artery (closed arrow head).

23. Pelvic Testes: A patient with complete androgen insensitivity syndrome. Individuals have XY genotype but are phenotypically female due to loss of function in the androgen receptor gene. The testes are undescended or partially descended - gonadectomy is recommended because of a significantly increased risk of malignancy [7] . Identifying the site of the testes can aid operative planning and look for malignant changes. One testis lies just proximal to the deep ring of the left inguinal canal (closed arrow head). The second testis lies against the right pelvic side wall and distended bladder (open arrow head). 

24. Inguinal Canal: Both testis lie at the inguinal canal with homogenous and intermediate T2 signal in a patient with complete androgen insensitivity (CAIS).

25. Cryptorchidism in a 19-year-old patient with androgen insensitivity syndrome (previously called testicular feminization syndrome). Coronal T2-weighted MR image demonstrates anomalously located bilateral testes (arrows) in the upper site of the inguinal canal.

26. Cryptorchidism in a 23-year-old patient with mixed gonadal dysgenesis. Axial fusion image of T2-weighted image overlaid by diffusion-weighted image, b factor 1000, demonstrates high signal intensity in undescended gonads (arrows).

27. Non-descended testis. Axial (a), coronal (d) and sagittal (e) FRFSE T2-weighted images show an ovoid mass with high signal intensity in the right IC. Testis has a relatively low signal intensity on axial 3D GRE T1-W image (b), with poor enhancement after gadolinium administration (c).

28. 5 years old boy presented with right sided clinically nonpalpable testis. MRI imaging revealed a right intracanalicular testis (arrowed), surrounded by mild vaginal hydrocele and showing intermediate signal intensity on axial T1WI (a), axial and coronal T2WIs (b and c), and marked hyperintensity on axial DWI (d) obtained with b value of 800 s/mm 2.  

29. Axial T1WI (a) shows isointense intra canalicular undescended right testis (arrow), axial DW MRI (b) obtained at a b value of 800 shows the hyperintense right intra canalicular right testis (arrow).

30. Axial fat suppressed T2WI (a), axial DW MRI obtained at a b value of 800 (b) shows the hyperintense left low intra-abdominal left testis (arrow).

31. Axial fat suppressed T2 WI (a), axial DW MRI obtained at a b value of 800 (b) shows the hyperintense high intra-abdominal right testis (arrow).

32. Diffusion restrictions are shown in the left undescended testis (arrow) on diffusion weighted image (A) and apparent diffusion coefficient (ADC) (B), right ovary (arrow) on diffusion weighted image (C) and apparent diffusion coefficient (ADC) (D).

33. 11-years boy with low intra-abdominal non-palpable undescended testis (left testis) Axial T1 weighted MR image B. coronal T2 weighted MR image C. fat suppression T2 weighted MR image (testis show hypo-intense in T1 , hyper intense on T2 , testis just proximal to left internal ring ) D. diffusion-weighted MR image with b value of 600 s/mm show markedly hyper intense testis.

34. 5  years old boy presented with right sided clinically nonpalpable testis. MRI imaging revealed a right intracanalicular testis (arrowed), surrounded by mild vaginal hydrocele and showing intermediate signal intensity on axial T1WI (a), axial and coronal T2WIs (b and c), and marked hyperintensity on axial DWI (d) obtained with b value of 800 s/mm 2 .

35. Atrophic undescended testis. A, Coronal MR image shows a small, intermediate–signal intensity testis (arrow) associated with low–signal intensity hydrocele (h). The signal intensity of the testis is low compared with that of fat (*). B, Another image slightly posterior to that in A shows the normally descended contralateral testis (curved arrow), which demonstrates high signal intensity similar to that of fat (*).

36. Torsion of undescended testis with gangrene of the left one.  

37. Thank You.