請問什麽是MRCP?並請幫看一下B超結果?多謝!

一年前因膽結石做了膽囊摘除手術,最近體檢做B超,結果如下:
There is an echogenic shadowing structure, which appears to be in the common bile duct, measuring 11x8mm...

結論:
There is evidence of choledocholithiasis in this patient who has had prior cholecystectomy, Futher evaluation with a MRCP may be of benefit if clinically indicated.

想請問一下這個B超結果是說膽總管結石嗎? 還是有別的可能才需要進一步做MRCP呢? MRCP對身體有沒有輻射或者別的不好呢?

見醫生還要等,很擔心,先在這裏問一下, 先謝謝了!