What investigation is most useful to determine whether a goitre is causing breathlessness in a patient with a normal chest examination?

In cases where a goitre is suspected to be causing breathlessness, particularly when the chest examination appears normal, a CT scan of the neck and chest is highly useful. This imaging technique provides detailed cross-sectional images of the neck and thoracic structures, helping to assess the size and extent of the goitre, and its relationship to surrounding structures such as the trachea and bronchi.

A CT scan can reveal whether the goitre is compressing these airways, which could explain the patient's symptoms of breathlessness. It also allows for the evaluation of other potential causes of obstruction or compression, including mediastinal masses or enlarged lymph nodes, which might coexist.

Other options, while relevant in different contexts, do not serve as effective first-line investigations in this scenario. For instance, bronchoscopy is invasive and primarily used to directly visualize the airway, which may not be necessary if imaging can provide a clear picture of the underlying issue. FVC (Forced Vital Capacity) measures lung function but would not identify structural problems caused by the goitre. An X-ray of the thoracic inlet might reveal some abnormalities, but it generally lacks the detail needed to fully assess soft tissue structures and is less sensitive than a CT scan in visualizing the go