Role of Medical Imaging in diagnosis and Presurgical Assessment of Androgen

Insensitivity Syndrome

DR. MUHAMMAD BIN ZULFIQARPGR II FCPS NEW RADIOLOGY DEPTT.

SIMS/SHL

IMAGING MODALITIES

• USG

• CT

• MRI

USG• Inexpensive, Safe and Widely Available

• More Sensitive if testis are located within or caudal to inguinal ring.

• Multi-approach ultrasound (including transabdominal, transvaginal, transperineal and occasionally transrectal) to identify the pelvic anatomy. On multimodality approach ultrasound is 89.8% accurate compared to 85.7% with MRI.

(Mansour et al.)

Mr./Miss X 14 Years Old

Seminal Vesicle

Prostate

Perabdominal USG shows no evidence of uterus and Ovaries.

• High resolution USG with linear array probe shows location of both testis in the inguinal canal.

MISS/MR. Y 8 Years OldMaternal Cousin to X

Perabdominal USG shows no evidence of Uterus and Ovaries.

High resolution USG with linear array probe shows location of both testis in the inguinal canal.

MR. Z 16 Years old Brother of X

• Perabdominal USG shows no evidence of uterus and Ovaries.

Penile Urethra

• High Resolution scan through penile shaft shows urethra. However no corpora cavernosa or spongiosa apppreciated.

• Both testis are visualized in scrotal sac. Both testis are normal in size and echotexture.

• Color Flow Imaging shows Normal Flow and Pattern in Testicular Artery.

Epididymis

USG Pitfalls

• Dependant on sonographer skill.

• Multimodality USG is a little bit more invasive especially in a virginal teenage girl presenting with pubertal development issues.

• Deep seated and fibrosed atrophic testis

MRI

• (MRI) has been studied more extensively.

• MRI is superior to USG in detection of undescended testis in AIS.

• Imaging in multiple planes and good contrast resolution.

• MRI has improved detection of intraabodminal gonads e.g. fibrosed testis.

• Abnormal internal anatomy more precisely depicted.

(Fenner et al), (Tanaka et al).

• Sagittal T2w-MRI confirms absence of the uterus and the proximal two thirds of the vagina. The distal rudimental vagina is visible (arrow).

• Axial T2 weighted MR image reveals bilateral inguinal canal testes (arrow 1) and atrophic epididymides (arrow 2).

• Coronal T2w-MRI shows testes near to superficial inguinal rings. Female external genitalia are also evident.

CT Scan

• Commonly used for detection or characterization of malignancy.

Disadvantage

– less accessible

– More costly than ultrasound

– There is exposure to ionizing radiation.

– CT scan does not characterize soft tissues as well, as MRI.

CONCLUSION

• Ultrasound is best choice for initial evaluation specially if testis are located in or caudal to inguinal canal and lower abdomen.

• MRI has been recommended as the preferred method of imaging in presurgical assessment if

– Not traced by USG

– Located intrabdominally.

– Fibrosed

• CT is only used for characterization of malignancy .

THANX