311- What is the role of different imaging modalities in the evaluation of
cryptorchidism?
Imaging modalities that can be used to localize the testes include ultraso-
nography, CT, and MRI; CT scan should be avoided to prevent radiation
exposure to the gonads. The sensitivity and specifi city of ultrasonography
and MRI in localizing non-palpable testes are summarized in the table given
below.Imaging modality Location Sensitivity (%) Specifi city (%)
Ultrasonography Inguinoscrotal 52 88
Intra-abdominal 44 93
MRI Inguinoscrotal 85 100
Intra-abdominal 55 100- How to differentiate between bilateral undescended testes and anorchidism by
hCG stimulation test?
The dose of hCG for the assessment of testosterone response depends on the
age of the child: 500 IU for infants, 1,000 IU for children aged 1–10 years, and
1,500 IU for >10 years. hCG is administered intramuscularly for 3 days and
serum testosterone is estimated at baseline and after 24h following the last
dose. A positive response is defi ned as a twofold rise in serum testosterone from
baseline or a peak testosterone level >5 nmol/L (radioimmunoassay) after hCG
stimulation test and denotes the presence of functioning Leydig cells. A nega-
tive response suggests anorchia.- When to evaluate a newborn for DSD?
All newborns with overt genital ambiguity should be evaluated for
DSD. Newborns with an apparent female external genitalia having isolated cli-
toromegaly, posterior labial fusion, or inguinal/labial mass require evaluation
for DSD. Newborns with apparent male genitalia and having external masculin-
ization score <11 also merit evaluation for DSD (e.g., those with isolated
micropenis will have EMS 9 and those with isolated proximal or mid-hypospa-
dias will have EMS 10 or less). In addition, those with familial hypospadias or
having discordance between prenatal karyotype and genital appearance require
evaluation for DSD.9 Disorders of Sex Development