Obstructive sleep apnea: diagnosis with ultrafast CT

Article Abstract:

Obstructive sleep apnea (temporary cessation of breathing during sleep due to a blockage or obstruction) often occurs in the upper airways of patients. This potentially serious disorder may be due to a reduction in the stimulus to the respiratory center, and is sometimes characterized by loud snoring. The disorder is potentially dangerous when occurring in persons suffering from arteriosclerosis, and heart and kidney disease. Patients suffering from sleep apnea are prone to daytime drowsiness. Anatomically, these patients are characterized by small oropharyngeal (mouth to larynx) and small nasopharyngeal (nose to mouth) airway openings. The purpose of the study was to determine differences in the size of upper airway openings between patients with obstructive sleep apnea and healthy volunteers. An ultrafast computed tomography (CT) scanner, capable of imaging the upper airway in near real time, was used to measure the oropharyngeal and nasopharyngeal airway openings in 11 patients with obstructive sleep apnea. It was shown that there are three factors determining the ability of an airway to open and remain open long enough for sufficient oxygen to be obtained during breathing: proper muscle tone of the dilator muscles of the upper airway; the degree of intra-airway pressure (related to total airway resistance that may be negatively affected by narrowing of the nasopharyngeal airway); and the cross-sectional dimension of the oropharyngeal opening (the smaller this opening, the greater the likelihood that proper negative pressure will not be obtained and maintained). Negative airway pressure during breathing is associated with the ability to draw air into the lungs. Use of ultrafast CT demonstrates that patients with obstructive sleep apnea have small oropharyngeal airways that collapse easily while the patients are awake. The combination of these factors is likely to cause collapse of the airway during sleep.

Research, Usage, Measurement, Sleep disorders, Sleep apnea syndromes, Sleep apnea, Medical imaging equipment, Oropharynx

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Fungal pulmonary infections after bone marrow transplantation: evaluation with radiography and CT

Article Abstract:

Bone marrow transplants (BMTs) are needed to treat some diseases. These transplants require that the patient's immune system be severely depressed to prevent rejection of the transplant. This depression of the immune system leaves the patient susceptible to many infectious diseases. Pulmonary (lung) infections are commonly found in BMT patients. Early diagnosis of these infections is imperative. This study examined the use of radiography (X-rays) and computed tomography (CT, computer generated images from X-ray scanning) in detecting fungal pulmonary infections in BMT patients. Fifty-five pairs of chest X-rays and CT studies were obtained from 33 BMT recipients who had fevers. Twenty-one of the pairs were from 13 patients diagnosed with fungal infection and nine pairs were from eight patients diagnosed with bacteremia (bacterial infection of the blood). Confirmation of disease was made using conventional methods and with white blood cell counts. Nodular or opaque (nontransparent) areas were found by CT in 20 of the 21 pairs of patients with fungal disease, but not in any of the nine pairs from the eight patients with bacteremia. These results indicate that CT may be able to differentiate between bacteremia and fungal pulmonary infections in BMT patients and may be accurate enough for noninvasive diagnosis of these infections, but the results need further confirmation. (Consumer Summary produced by Reliance Medical Information, Inc.)

CT imaging, CAT scans, Bone marrow, Bone marrow transplantation, Lung diseases, Fungal, Fungal lung diseases, Bacteremia, Radiography

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Vertebral compression fractures: distinction between benign and malignant causes with MR imaging

Article Abstract:

This retrospective study of hospital charts and radiologic procedures deals with the appearance of vertebral compression fractures (collapsed vertebra) by various imaging techniques, including computed tomography (CT) and magnetic resonance imaging (MRI). Both of these techniques give similar images of the body but differ in the physics used to obtain an image (CT uses X-rays and MRI uses a strong magnetic field and radio waves). MRI was performed on 64 patients with 109 incidents of vertebral compression fractures that could not be diagnosed using conventional X- ray methods. Of this group 25 cases were related to an underlying cancer and 84 were caused by other non-cancer related (benign) processes. Twenty-two cases in the cancer group had a distinctive appearance by MRI which showed the replacement of the contained bone marrow space of the vertebra by tumor. All of the patients in the benign group either retained complete (47 cases) or partial (14 cases) integrity of the vertebral bone marrow space. The ability of MRI to accurately differentiate malignant from benign causes of vertebral compression was 94 percent. The study indicates that MRI may be a useful additional diagnostic procedure in cases of vertebral compression fractures.

Complications and side effects, Magnetic resonance imaging, Metastasis, Cancer metastasis, Vertebrae, Spinal fractures

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