How a HIDA Scan is Useful to Evaluate Liver Function in the Case of Unexplained Abdominal Pain
HIDA scanning (hepato-intestinal double isotope scan), more commonly called a HIDA scan, is a type of nuclear medicine test. The test can help your doctor assess how effectively the bile flows through your liver and out of your small intestine.
The HIDA Scan is a special type of nuclear medicine scan that is similar to the Gallium scan (gallium 68 scan) in functionality, but uses technetium 99m as the nuclear medicine tracer. The scan involves taking a small amount of radiopharmaceutical and injecting it into the body on site. The radioactive material travels through the body to the part of the body which is being examined by the test.
During abdominal imaging procedures, you may receive more than one type of radioactive tracer. The scan with the newly arrived tracer is called an “acquisition study” (or scan). Because the tracer is still being moved through your body by the blood flow, it is possible to detect where it has gone by using a scanner. From this information, pictures or video can be created. The time required for an additional scan to be produced after receiving another type of radioactive tracer is called the “washout period.” You will not be exposed to anywhere near the amount of radiation from a tracer that you received during an earlier scan as compared to if you were given a new tracer at a later time.
Diagnostic Imaging is often unnecessary in chronic abdominal pain. In particular, undifferentiated abdominal pain is rarely an indication for a CT scan in the absence of alarm features such as neutropenia or severe weight loss.
The widespread use of computed tomography (CT) has created an industry that serves more patients than ever before, with an expected 6.5 million CT scans performed in the United States each year. But CT is a misused diagnostic tool that can cause, despite the high cost and low risk, life-altering consequences including missing cancers.
New data presented at RSNA 2016 examined the effect of imaging in patients presenting with nonspecific abdominal pain, and showed that only 18 percent of such patients have evidence of serious diseases requiring immediate intervention yet underwent testing anyway.
The diagnostic approach to patients with alarm symptoms of gastrointestinal bleeding includes a detailed personal and family history, physical examination, and investigations such as laboratory tests, imaging techniques (such as endoscopy or CT) or histology. The most appropriate techniques depend on the presentation.
The request form should include as much clinical information as possible, including the suspected lesion(s), age, sex and past medical history of the patient. This forms an important part in the selection of appropriate studies, scanning protocol, recommendation and subsequent management.
Chronic abdominal pain is common in primary care. In many cases, chronic abdominal pain is part of a functional syndrome. Pulmonary, cardiac or disseminated cancer are all causes of a sudden onset of abdominal pain which should immediately raise the suspicion of malignancy.
Radiological investigations are crucial to the diagnosis and management of many conditions. Particularly in patients with abdominal pain, computed tomography (CT) is frequently requested and performed, but does not necessarily add to the value offered by other commonly used investigations for evaluating abdominal pain.
Radiologists have been scrutinized for ordering unnecessary CT scans—an ‘incidentaloma’ is a tumor detected incidentally during a CT scan done for another reason, often leading to a cascade of further tests resulting in further risk, anxiety and cost. At least one case of unnecessary total gastrectomy has been reported as a result of an incidentaloma.
Several imaging techniques may be used to look at the hip. Ultrasound (US) is the mainstay of imaging for arthritic hips and is particularly useful where there are no bony abnormalities. Conversely, conventional radiographs (X-ray) will show any bony changes in a very detailed manner and are useful for most other causes of hip pain such as slipped femoral epiphysis. Furthermore, magnetic resonance imaging (MRI) or CT may be used to look at soft tissue structures such as tendons and/or muscle injury.
USG is a safe, cost effective and readily available technique for examination of the bowel if performed in accordance with the manufacturers’ instructions. It has several advantages over other modalities of examination such as CT scanning, MRCP and MRI. The limitations of the study include operator dependence, the need for bowel preparation which makes the method unsuitable for children and other groups where bowel control is poor and availability.
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