Bone density scanning, also called dual x-ray absorptiometry (DXA) or bone densitometry, is an enhanced form of x-ray technology that is used to measure bone mineral density (BMD) or bone loss. DXA is most often performed on the lower spine and hips although the whole body is sometimes scanned. DXA is commonly used to diagnose osteoporosis, a condition that involves loss of calcium along with structural changes that cause the bones to become brittle and more likely to break. The DXA machine sends a thin, invisible beam of low-dose x-rays with two distinct energy peaks through the bones being examined. One peak is absorbed mainly by soft tissue and the other by bone. The soft tissue amount can then be subtracted from the total so that the remainder is the patient’s bone density. Special software is used that can compute and display the bone density measurements on a computer monitor.
Endoscopy typically refers to looking inside the body for medical reasons using an endoscope — an instrument used to examine the interior of a hollow organ or cavity of the body. Unlike most other medical imaging devices, endoscopes are inserted directly into the organ. There are several types of traditional endoscopy. Those using natural body openings include upper endoscopy, gastroscopy, enteroscopy, colonoscopy, and sigmoidoscopy. Endoscopies are usually performed under sedation to assure patient comfort. In recent years, newer forms of endoscopy have been developed where tubes are not inserted directly into the body.
Extracorporeal membrane oxygenation (ECMO) is a procedure that uses a machine to take over the work of the lungs and sometimes the heart. Extracorporeal means that the blood circulates outside of the body with the help of a machine. Membrane oxygenation, referred to as the “artificial lungs,” is a special part of the machine that puts oxygen into the blood and takes out carbon dioxide just like the lungs do normally. Although similar to a heart-lung machine that is used during open-heart surgery, ECMO therapy is intended for patients whose heart and lungs cannot normally function on their own. ECMO is used to provide intensive care for babies, children and adults. The two most common modes of ECMO are veno-venous (VV) where access is via a vein for patients who have suffered loss of the lungs exclusively and veno-arterial (VA) with dual access by a vein and the carotid artery for patients with both lung and heart impairment.
Sleep disorders testing uses polysomnography (PSG) — a comprehensive recording of the biophysiological changes that occur during sleep. PSG monitors many body functions, including brain activity (electroencephalography), eye movements (electrooculography), muscle activity or skeletal muscle activation (electromyography), and heart rhythm (echocardiography). Sleep studies are usually performed at night, when most people sleep, although some people with circadian rhythm sleep disorders may be tested at other times of day. A polysomnogram records a minimum of 12 channels requiring at least 22 wire attachments to the patient, which converge into a central unit connected to a computer system for displaying, recording, and storing the data. The channels vary depending on the physician’s request. During sleep, multiple channels can be displayed continuously and a small infrared video camera can be positioned in the room so that the technician can observe the patient on a monitor from an adjacent control room.
This article is an update of a previous post.
The ability to record diagnostic images digitally and upload them to a picture archiving and communication system (PACS) has largely been a radiology-oriented system since the technology was formally introduced in the early 1980s. Enterprise imaging is the next evolutionary step in image storage and management. It will take the responsibility for imaging management away from radiology and place it in the hands of the enterprise-wide information technology function. The path to enterprise archiving of images is being paved by vendor-neutral archives (VNAs) that enable easier integration of data from disparate systems throughout the hospital — such as radiology, cardiology, pathology, orthopedics, and obstetrics — and make these data available in one place via the electronic health record. This evolution will have the capability to store and exchange clinical content in DICOM (digital imaging and communications in medicine) and non-DICOM formats. As a result, all clinical data will be available, easily accessible, and useable and not contained in departmental silos but on a monitor from an adjacent control room.
This article is an update of a previous post.
Pulmonary function testing measures the function of lung capacity and lung and chest wall mechanics to determine whether or not the patient has a lung problem. Pulmonary function testing is commonly referred to as “PFT” and such tests are usually performed by Certified or Registered Pulmonary Function Technologists (CPFT or RPFT) who are credentialed by the National Board for Respiratory Care (NBRC). When a patient is referred for pulmonary function testing, it means that a battery of tests may be carried-out including simple screening spirometry, static lung volume measurement, diffusing capacity for carbon monoxide, airways resistance, respiratory muscle strength, and arterial blood gases. Spirometry is the standard method for measuring most relative lung volumes; however, it is not capable of providing information about absolute volumes of air in the lung. Thus a different approach is required to measure residual volume, functional residual capacity, and total lung capacity. Two of the most common methods of obtaining information about these volumes are gas dilution tests and body plethysmography.
Body plethysmography is a very sensitive lung measurement used to detect lung pathology that might be missed with conventional pulmonary function tests. This method of obtaining the absolute volume of air within one’s lungs may also be used in situations where several repeated trials are required or where the patient is unable to perform the multibreath tests. The technique requires moderately complex coaching and instruction for the patient.