role of medical imaging in diagnosing ais and presurgical assesment in such patients
TRANSCRIPT
Role of Medical Imaging in diagnosis and Presurgical Assessment of Androgen
Insensitivity Syndrome
DR. MUHAMMAD BIN ZULFIQARPGR II FCPS NEW RADIOLOGY DEPTT.
SIMS/SHL
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.)
Penile Urethra
• High Resolution scan through penile shaft shows urethra. However no corpora cavernosa or spongiosa apppreciated.
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 .