Xrays

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Hi Noah,

I hope the following (which I pulled from internet sources) will be helpful in answering your questions about what Xrays can diagnose. In my clinical experience at work, spirometry and patient history are the gold standard for diagnosing both COPD and asthma. Xrays are rarely used for asthma unless the patient presents in a crisis and pnuemonia or something else is being considered as a differential diagnosis where I work. Sometimes an Xray will be done during a workup to exclude other possible diagnoses if the patient presentation is complicated and the the diagnosis is not clear. I believe the sweat test is considered the gold standard for diagnosing cystic fibrosis, although I don't do pediatrics.

Pulmonary Function Tests (PFTs) Pulmonary function tests are the primary diagnostic tools for COPD, after the medical history and physical examination. These tests demonstrate characteristic abnormalities in lung function that, in the proper clinical context (i.e., medical history, physical examination, chest x-ray) confirm or support the diagnosis of COPD and give some idea of the degree of impairment and prognosis

Radiology Chest x-ray is an imprecise method of diagnosis of COPD. It is only consistently abnormal in severe cases and should be performed in the initial evaluation to exclude other lung diseases. Findings characteristic of COPD in chest x-ray are hyperinflated lungs with flattened diaphragm, hyperlucent lungs (chest film shows greater than normal film blackening from increased transmission of x-rays), and central pulmonary artery enlargement. Bullae, areas of destroyed lung tissue that create large dilated air sacs, may be seen as well.

CT scan may be used to more accurately diagnose emphysema. This is usually not necessary, however, and abnormal lung anatomy is not always detected.

Original source: www.pulmonologychannel.com

Sweat test. The sweat test is the most common diagnostic test for cystic fibrosis. A small amount of a chemical called pilocarpine is rubbed on the patient's arm or leg. An electrode that generates a small, painless electric current is placed on the spot to induce sweating. A gauze pad or filter paper is used to cover the spot for about 30 minutes. The sweat collected is then analyzed and the level of chloride (a chemical in salt) present is measured. High levels of chloride may indicate cystic fibrosis. The test cannot indicate the severity of cystic fibrosis.

Chest x-ray. This imaging test can reveal scarring resulting from the chronic inflammation associated with cystic fibrosis.

(source from pediatric diagnosis:cystic fibrosis)

A chest x-ray is not generally helpful in diagnosing asthma. Doctors use chest x-rays when considering another diagnosis. However, a chest x-ray is often obtained when a person with asthma needs to be hospitalized or is treated in the emergency department with severe asthma.

A doctor suspects asthma based largely on a person's report of characteristic symptoms. More commonly, the doctor performs spirometry or pulmonary function tests before and after giving the person an inhaled beta-adrenergic agonist. Spirometry is also used to assess the severity of the airway obstruction and to monitor treatment. Peak expiratory flow (the fastest rate at which air can be exhaled) can be measured using a small handheld peak flow meter. (source from respiratory-lung health care)

Hope that is helpful,