You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Investigation of choice for dysphagia for solids - and explain in detail?
Dysphagia for solid food may be due to mechanical causes like: Carcinoma Peptic and other benign strictures Lower oesophagal ring The investigation of choice in mechanical obstruction is endoscopy Barium swallow is the first investigation Ref : CMDT 2005, p 547