Koirala's personal physician Dr Kabir Nath Yogi has advised him to undergo a thorough medical checkup in a well-equipped hospital, according to the Prime Minister's personal aide.
During a CT-scan, a scar was seen in Koirala's lungs, according to his personal doctor.
Prime Minister Koirala, who is suffering from lung infection for some time, has been taking regular medication for bronchitis.
Koirala, who is also the president of ruling Nepali Congress party, has long been a smoker, which is seen as being responsible for the disease.
More From This Section
Koirala has been suffering from dry cough and fever for the last four weeks, according to the doctors.
The Prime Minister will get his health checkup at New York's Memorial Sloan-Kettering Cancer Centre, said Basanta Gautam, chief secretary at the Prime Minister's office.
Koirala has been visiting New York every year for follow up after he underwent surgery for tongue cancer about 5 years ago.
Now he will visit New York probably in the third week of June for thorough medical checkup.
While visiting USA for regular medical follow up Koirala will also have better medical checkup of his other health conditions including the problems related to the lungs, said chief secretary Gautam.