Radiological Investigation I: X-ray and CT

Chest X-rays capture images of the chest, heart, lungs, and blood vessels to detect various abnormalities including fluid buildup, tumors, foreign bodies, and other pathological conditions. These non-invasive images help screen and diagnose respiratory issues, typically using two views: posteroanterior and lateral projections taken after full inspiration when the lungs are well-aerated.

CT scans provide detailed, cross-sectional images of the body, making them superior for diagnosing lesions difficult to assess with standard X-rays, such as pulmonary nodules, small tumors near pleural surfaces, mediastinal abnormalities, and hilar adenopathy. CT scans can be performed with or without contrast medium, which is often iodine-based to enhance image clarity.

Patients should undress from the waist up and wear a gown, removing any metal objects between the neck and waist that could interfere with image quality. The procedure does not require fasting and is painless. Patients must be able to take a deep breath and hold it briefly while the image is captured for complete lung visualization.

Before contrast administration, nurses must evaluate blood urea nitrogen (BUN) and serum creatinine levels to assess kidney function, as contrast is contraindicated in patients with impaired renal function. Nurses should also determine if the patient has shellfish allergies, which may indicate iodine allergy, since the contrast medium is typically iodine-based.

Patients must lie still on a hard table while the scanner revolves around their body. If contrast medium is used, patients may experience a sensation of warmth and flushing during injection. Patients should be well-hydrated before and after the procedure to aid in contrast excretion, and the procedure typically takes several minutes.

Contrast medium is contraindicated in patients with impaired kidney function, known iodine allergies, or a history of adverse reactions to contrast media. During pregnancy, contrast use is typically avoided unless benefits significantly outweigh risks. In these cases, alternative imaging techniques or non-contrast CT scans may be considered instead.

Severe obesity may exceed the scanner's weight limit, requiring alternative imaging methods. Claustrophobia can affect patient comfort, though newer open or wide-bore CT scanners help alleviate this issue. CT scans are generally avoided during pregnancy unless necessary due to potential fetal risks, and endoscopic studies like bronchoscopy and thoracoscopy may be considered as complementary diagnostic options.