Defining the normal temporomandibular joint: closed-, partially open-, and open-mouth MR imaging of asymptomatic subjects

Article Abstract:

The temporomandibular joint (TMJ) of the jaw has become a subject of increasing interest in recent years. Some have speculated that TMJ abnormalities are the cause of a number of mild to serious problems. Magnetic resonance (MR) imaging is used to study the TMJ. It provides excellent images of soft tissues when the jaw is in a variety of positions. A major problem with using MR to examine the TMJ is that no standards for normal and abnormal findings have been set. Traditional determinations of TMJ abnormalities have relied on displacement of the meniscus (joint cartilage) when the mouth is imaged in open and closed positions. The TMJ's of 30 volunteers who had no symptoms of TMJ abnormalities were examined to determine a normal range for the position of the meniscus, characterize normalcy of the TMJ, and identify the best procedures for imaging the joint. Fifty TMJ's were imaged in the 30 volunteers. The MR results showed that the meniscus was clearly visible in 92 percent of the cases. It was easier to observe the meniscus in images taken with the mouth open than in either closed-mouth or partially open-mouth views. However, consistency in the location of the meniscus was much more variable in the open- and partially open-mouthed views, suggesting that the close-mouthed view is better for standardization. A number of subjects who had previous orthodontic work were found to have TMJ abnormalities; their results were not used in the normalcy assessment. No TMJ abnormalities were noted in any of the subjects without a history of orthodontic work or trauma. Data from the ''normal'' group was used in developing a normal range of meniscus displacement. It was determined to be not more than a 10 degree deviation from a 12 o'clock position. The presence of fluid in the TMJ was uncommon. This was an important finding since joint fluid is observed when the TMJs of symptomatic patients are imaged. These results suggest that MR imaging can be a reliable technique to use in diagnosing TMJ abnormalities. (Consumer Summary produced by Reliance Medical Information, Inc.)

Abnormalities, Magnetic resonance imaging, Temporomandibular joint disorders, Temporomandibular joint

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Pulmonary embolism after hip or knee replacement: postoperative changes on pulmonary scintigrams in asymptomatic patients

Article Abstract:

Pulmonary embolism, or blood clots in the lung, is a common medical complication following major orthopedic procedures of the lower extremities, such as hip or knee replacement. A frequency of two to 16 percent of patients who have undergone total hip or knee replacement, develop pulmonary embolism which remains the largest single cause of mortality in these patients. The diagnosis of pulmonary embolism is often difficult, since the patient may not exhibit signs or symptoms. Serial pulmonary imaging has aided the diagnosis of postoperative pulmonary embolism in these asymptomatic patients. The researchers evaluated 400 patients with serial imaging techniques to determine the significance of changed postoperative images in asymptomatic patients who had undergone total hip or knee arthroplasty. Twenty-two patients had significant changes on postoperative images. Seventeen were asymptomatic. Overall, 76 percent of all asymptomatic patients with significantly changed postoperative images were found to have pulmonary emboli following a lung scan. Furthermore, documented pulmonary emboli were demonstrated in 100 percent of patients whose postoperative images changed. A 'changed' postoperative lung scan, therefore, clearly indicates the high probability of pulmonary embolism. Anticoagulant therapy can be initiated with confidence in patients with changed postoperative ventilation-perfusion scans. The researchers believe that serial pulmonary imaging is a sensitive, easily reproducible, and noninvasive method for evaluating pulmonary embolism in a high risk population. It is recommended that this serial scanning protocol be part of the routine care of patients undergoing total hip or knee replacement since it was found that asymptomatic patients are also likely to be suffering from pulmonary emboli.

Complications and side effects, Lungs, Lung, Pulmonary embolism, Orthopedic surgery, Radionuclide imaging, Arthroplasty

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Pulmonary edema in cocaine smokers

Article Abstract:

Pulmonary edema, or fluid retention in the lungs has been observed in cocaine or "crack" abusers. This feature of cocaine abuse is not well-known either among radiologists or among other medical specialists. Unless the possibility of cocaine smoking is raised, the radiographic changes may be falsely attributed to acute myocardial infarction or opportunistic or atypical pneumonia, because patients are often reluctant to reveal a history of drug use. The researchers observed pulmonary edema in five patients who had no physical or laboratory evidence supporting a specific reason for the existence of pulmonary edema. All five patients had abnormal findings on chest x-rays following admission to the emergency room. All of the patients were presumed to have smoked cocaine within 24 hours prior to admission. No preexisting risk factors for pulmonary edema were present in any of the five patients. The diagnosis of cocaine-related pulmonary edema was based on the temporal relationship between cocaine use and the onset of symptoms, the x-ray findings, and the rapid resolution of the symptoms. It is known that the incidence of cocaine-caused pulmonary edema is small. However, the rise in the use of cocaine mandates that radiologists be aware of this radiographic manifestation. In a young, otherwise healthy patient without known cardiopulmonary risk factors, the presence of pulmonary edema on a conventional x-ray image should alert the radiologist to the possible diagnosis of cocaine smoking, especially if the patient has a history of drug abuse.

Causes of, Physiological aspects, Pulmonary edema, Cocaine, Chest, Thorax

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