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The Haller index, created in 1987 by J. Alex Haller, S. S. Kramer, and S. A. Lietman, [1] is a mathematical relationship that exists in a human chest section observed with a CT scan. It is defined as the ratio of the transverse diameter (the horizontal distance of the inside of the ribcage ) and the anteroposterior diameter (the shortest ...
For example, if the reader thinks the x-ray being read has profusion most like the standard x-ray for category 1, but serious considered category 2 as an alternative description of the profusion, then the reading is 1/2. Close-up right lower zone 2/2 S/S Large opacities: A large opacity is defined as any opacity greater than 1 cm in diameter.
In anteroposterior (AP) views, the positions of the x-ray source and detector are reversed: the x-ray beam enters through the anterior aspect and exits through the posterior aspect of the chest. AP chest x-rays are harder to read than PA x-rays and are therefore generally reserved for situations where it is difficult for the patient to get an ...
Recognized effects of higher acute radiation doses are described in more detail in the article on radiation poisoning.Although the International System of Units (SI) defines the sievert (Sv) as the unit of radiation dose equivalent, chronic radiation levels and standards are still often given in units of millirems (mrem), where 1 mrem equals 1/1,000 of a rem and 1 rem equals 0.01 Sv.
The main chest X-ray findings that can suggest inactive TB are: [2] 1. Discrete fibrotic scar or linear opacity—Discrete linear or reticular densities within the lung. The edges of these densities should be distinct and there should be no suggestion of airspace opacification or haziness between or surrounding these densities.
It refers to the dilatation and abrupt change in calibre of a previously normal descending pulmonary artery on a chest X-ray film. [1] Chang sign usually appears within 24 hours of the onset of chest pain due to pulmonary embolism, [ 2 ] and the maximal dilatation of the descending pulmonary artery often occurs in two to three days after the ...
Number of chest X-rays resulting in same effective dose Skull radiography (X-ray) 0.015 1 Chest X-ray 0.013 1 Lumbar spine X-ray 0.44 30 Abdomen X-ray 0.46 35 Pelvis X-ray 0.48 35 Screening mammography (4 views) 0.2 15 Dental X-ray (intraoral) 0.013 1 Diagnostic fluoroscopy: barium swallow 1 70 Cardiac angiography 7 500 Head CT 2 150 Chest CT 10
While the chest x-ray is normal in the majority of PE cases, [2] the Westermark sign is seen in 2% of patients. [3] Essentially, this is a plain X-ray version of a filling defect as seen on computed tomography pulmonary arteriogram. The sign results from a combination of: the dilation of the pulmonary arteries proximal to the embolus and