The different types of x-ray examinations

Identify the different types of chest x-ray examinations and when to order them.

Julian Dobranowski, MD FRCPC FCAR
Julian Dobranowski, MD FRCPC FCAR
6th Dec 2017 • 4m read

There are different types of chest x-ray exams and the one you decide to order for your patient will depend entirely on what you need to find out. By the end of this lesson, you'll know nine different types of chest X-ray examinations and when to order them.

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Video Transcript

[00:00:00] What will I gain from this video? You will learn about different types of radiological examinations of the chest and which ones to order to answer your clinical questions. We can image the chest using various technologies and techniques. The choices we have include the posterior-anterior x-ray or the PA x-ray, the lateral chest x-ray,

[00:00:30] the anterior-posterior or AP x-ray, the decubitus view, the lordotic view, the inspiration / expiration series, chest fluoroscopy, dual-energy chest x-ray, digital tomography or tomosynthesis. The preferred examination is the posterior-anterior x-ray. This examination is usually performed

[00:01:00] in the x-ray department, with the patient standing with their anterior chest closest to the x-ray detector. The x-ray beam courses through the chest, from back to front or from posterior to anterior. This orientation minimizes the magnification of the heart. The exposure is taken at maximum inspiration. In order to do a PA examination, the patient must be able to stand or

[00:01:30] sit upright, take a deep breath and hold it, to understand instructions, and to cooperate. The lateral chest x-ray is commonly ordered together with the PA view. The two examinations are complementary and when combined, allow the viewer to create a mental three-dimensional perspective of the chest. When the lateral x-ray is performed, the patient is positioned so that the left side of the chest lies adjacent

[00:02:00] to the x-ray detector. The x-ray beam courses through the chest from right to left. In order to do a lateral x-ray, the patient must be able to stand or sit upright, take a deep breath and hold it, to understand instructions, and to cooperate. The anterior-posterior x-ray is reserved for a patient that cannot have a conventional PA and lateral. This is reserved for critically

[00:02:30] ill patients. The examination is usually performed with the patient sitting or in a supine position and the x-ray detector is positioned behind the patient's back. The examination is usually taken with mobile equipment. The x-ray beam courses through the chest from front to back or from anterior to posterior. If possible, the exposure is taken at maximum inspiration. On a standard x-ray, it may be difficult to

[00:03:00] differentiate between pleural thickening, consolidation, and a pleural effusion. Ultrasound is the examination of choice in this scenario. If ultrasound is not available, then a decubitus x-ray can be ordered. The decubitus x-ray is performed with the patient horizontal, lying on the side of the question abnormality. In this case, we see that there is this whiteness within the left hemithorax, so we question whether this may be a pleural effusion. If we

[00:03:30] position the patient with the left side down, we see that there is separation of the lung, with this whiteness from this point to the ribs, indicating that this represents a pleural effusion. The lung apices can be a difficult region to evaluate, due to the overlap of the ribs and the clavicles. In situations where a suspected apical pulmonary abnormality exists, the lordotic technique is used to confirm the finding. The lordotic

[00:04:00] technique is performed by orienting the x-ray beam from inferior to superior, at an angle upwards towards the patient's head, thereby, separating the anterior portion of the first ribs and the clavicle, from the lung apices. The examination eliminates the overlap of anatomical structures, from the top of the lungs. When the patient takes a limited inspiration, the opacity of the lungs will be greater than during a full inspiration

[00:04:30] because there is less air within the lungs. Although, in most scenarios, this is not desirable, it is used to our advantage in patients with a pneumothorax, by making the lungs wider. By taking the x-ray during expiration, air outside the lungs, in the pleural space, will appear more obvious. In this case, we have an inspiration film where no abnormality is detected in the apices. On the expiration film

[00:05:00] on close examination, we can identify that there is a left apical pneumothorax present. Chest fluoroscopy, is a technology that is real-time x-ray imaging, using a low dosed technique. When the radiologist presses a pedal, he can look at the thoracic structures in real- time. You can see the heart beating but you can also see the movement of the diaphragms.

[00:05:30] This type of examination is currently limited to evaluation of diaphragmatic movement, in patients with suspected phrenic nerve paralysis. With phrenic nerve paralysis, there is a paradoxical movement of the diaphragms on expiration, which can be readily identified with this technology. Digital tomography is a technology that with post-processing, an x-ray image

[00:06:00] can be subdivided into various layers, very similar to a CT examination. Thereby, also eliminating the issues of overlap and hiding of structures because of overlap. So, to recap, the type of chest x-ray examination you'll order will depend on the specific needs of the patient and the clinical indications. The PA and lateral x-ray

[00:06:30] is the preferred examination and is the examination most often ordered and performed. The AP examination is limited for critically ill patients. The decubitus view is ordered for patients with suspected pleural effusion and differentiating pleural effusion from pleural thickening and pleural tumors. Lordotic view is ordered in order to eliminate overlap of bony structures with the

[00:07:00] lung apices. Expiration view is ordered when a pneumothorax is suspected.