We suggest performing a radionuclide brain perfusion study employing a lipophilic radiopharmaceutical such as 99mTc-HMPAO or equivalent (which incorporates both a flow and parenchymal phase) with or without tomographic imaging in pediatric patients who require ancillary investigation for DNC (weak recommendation, low certainty in evidence). We suggest performing a radionuclide brain flow study employing a lipophobic radiopharmaceutical such as 99mTc-DTPA, 99mTc-GHA, 99mTc-pertechnetate, or equivalent (which incorporate only a flow phase) when a study employing a lipophilic radiopharmaceutical cannot be performed in pediatric patients who require ancillary investigation for DNC (weak recommendation, low certainty in evidence). We suggest against performing EEG, transcranial Doppler, BAEP, SSEP, CT angiography, and four-vessel angiography in pediatric patients who require ancillary investigation for DNC (weak recommendation, very low certainty in evidence). We suggest against performing ancillary investigation in infants under two months corrected gestational age who require ancillary investigation for DNC (weak recommendation, very low certainty in evidence).