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In evaluating lobar volume loss differentiation between the upper and middle lobes of the lung may be difficult with conventional computed tomography (CT) scanning or by using bronchography (a method for imaging lungs following the injection of a dye). A new method using thin-section, high-resolution CT was employed by researchers to obtain an accurate evaluation of lobar volume loss. Using this new method researchers evaluated the CT scans of 117 patients, including 54 with lobar volume loss. The new method is capable of evaluating subsegmental (i.e., much greater anatomical specificity) portions of the lung bronchi and differentiating between upper and middle lobes more accurately than is permitted by conventional CT imaging techniques.

Computed tomography (CT) scanning was performed on 142 patients suspected of having an endobronchial tumor (tumor of the smaller bronchi of the lungs) to evaluate the accuracy and effectiveness of CT. All of the patients had undergone CT and bronchoscopy; diagnoses were confirmed by bronchoscopy in 110 patients and by bronchoscopy and surgery in the remaining 32. The CT scans were interpreted by two experienced radiologists. The results of this study demonstrate that CT is effective in showing the correct location and extension of a bronchial mass. CT was also able to locate tumors of a size less than one centimeter. It was noted that CT may overlook small tumors growing in the bronchial wall that do not cause narrowing or thickening of the wall. Tumors associated with local inflammation and swelling may also be overlooked or misdiagnosed with CT. These two types of tumors can be diagnosed by bronchoscopy and tissue biopsy. The researchers recommend CT as the first method of choice to visualize the endobronchial and extrabronchial parts of a mass or lesion. However, they emphasize that CT cannot replace bronchoscopy or tissue biopsy. It is their conclusion that CT and bronchoscopy should be applied as complementary diagnostic methods. CT can be most effectively used in cases where a tumor is suspected and a chest image is needed to guide bronchoscopy, or in those patients with normal chest radiographs who, despite normal or inconclusive bronchoscopy, are still suspected of having a bronchial mass.

A technique potentially useful for studying heart wall motion (contraction) is proposed for application with magnetic resonance (MR) imaging. Direct demonstration of the contraction of the heart has proven to be difficult with MR. Most imaging techniques only show the inner or outer surfaces of the heart, but not the motion of the heart muscle itself (myocardium). Conventional MR and computed tomography (CT) imaging can show the wall thickness but not motion within the wall. The technique proposed by the researchers permits magnetic labeling of the myocardium to directly demonstrate myocardial motion across its thickness and at many locations in the heart. A three-dimensional imaging technique is required in order to prevent MR images of curved heart surfaces from being confused with myocardial motion. The proposed technique, SPAMM (spatial modulation of magnetization), is believed to provide a simple and effective means of directly demonstrating cardiac motion. It is also useful in studying blood flow, cerebrospinal fluid movement, and in evaluating blood flowing through a clotted vessel.

Chest trauma is one of the main causes of death in children older than one year of age. It is critical to provide fast diagnosis of injuries in the thoracic region (between the base of the neck and the diaphragm) because delay severely hinders chances for survival. Diagnosis of thoracic injury in children is difficult, however, due to the lack of identifiable symptoms. Images provided by portable X-ray, the imaging technique often used in these types of cases, has not been a satisfactory means of assessment. The study evaluated the use of computed tomography (CT) scanning compared to portable chest X-ray in 62 cases of blunt abdominal trauma in children. Twenty-four hours after the injury, assessment of cardiopulmonary (heart-lung) damage should be made. Cardiopulmonary involvement in cases of blunt chest trauma is not normally evident until 24 hours has elapsed, particularly in young children who have a soft, flexible thorax which permits internal injury to occur without skeletal injury. X-ray imaging underestimated more than 33 percent of chest injuries that were subsequently viewed on CT scans. CT scans were able to demonstrate abnormality not depicted on chest X-ray images. The research found that CT scanning of the chest performed in conjunction with CT scanning of the upper abdomen is helpful in the early recognition of thoracic injuries that may not be symptomatic during the first 24 hours following trauma to the chest.

Human immunodeficiency virus (HIV) has been implicated as the primary cause of many symptoms associated with AIDS (acquired immunodeficiency syndrome). High rates of lymphoma (tissue growth in the lymphatic system) have been reported among AIDS patients, but the cause for this high rate is unknown. Ultrasound (US) was used to evaluate 38 AIDS patients with abdominal lymphomas. The results of US studies were compared with findings derived from computed tomography (CT) studies. AIDS-related lymphomas (ARL) of the abdomen are aggressive (fast growing) and likely to spread to other systems of the body, particularly the central nervous system (CNS) and bone marrow. The outlook for AIDS patients with lymphomas is poor. US examination of ARL of the abdomen also shows obstruction of the bile ducts, bile duct thickening, and gallbladder wall thickening. US depicted masses of varying sizes and shapes within abdominal organs, particularly the liver, in 87 percent of the cases studied. Lesions (abnormal tissue growth) in the spleen and kidney, however, were infrequent. The study concludes that patients with AIDS, or those at risk for AIDS, should undergo US examination of the abdomen for the presence of masses (cell growth) that may suggest the existence of ARL of the abdomen. There are limitations associated with US evaluation or testing for ARL of the abdomen, therefore, CT is recommended as an exploratory imaging technique for ARL of the abdomen in its initial stages. CT proves superior to US as a means of providing anatomic information concerning the precise extent of the spread of the disease. Until more testing occurs, researchers do not favor either CT or US as a means for evaluation of ARL of the abdomen.

It is important to evaluate complications associated with damage to the spleen (an abdominal organ containing sponge-like lymphatic tissue composed of phagocytes, cells that destroy substances foreign to the body such as bacteria, protozoa, dust, and other matter). The spleen is the organ most often injured during blunt abdominal trauma which may cause extensive bleeding (intra-abdominal hemorrhage) that often results in the removal of the spleen (splenectomy). Although the spleen has a well-known ability to heal on its own, the use of conservative (non-surgical) treatment strategies is encouraged due to the high risk of infection following splenic surgery. Better diagnostic techniques will improve nonoperative treatment for adult patients with splenic injuries. Although nonoperative treatment of pediatric splenic trauma is common, it is difficult to treat adults with trauma to the spleen without surgery. Research was conducted to develop a computed tomography (CT) method for grading (ranking) the severity of adult splenic trauma as a means of improving the decision-making process that leads to either surgical or non-surgical treatment of splenic injuries. Improved CT imaging techniques may reduce the incidence of performing exploratory laparotomy (surgical opening of the abdomen). To date, however, CT has not been capable of revealing injuries that were not suspected. Splenic injury evaluation and grading took place among 64 adult patients 24 hours after trauma to the abdomen. A grading system was developed, through the evaluation of CT images, which evolved into a statistical tool for ranking the severity of splenic injury. This ranking system was applied to a probability value that helped the physician predict the severity of the injury and the likelihood that the CT image had not identified an injury to the spleen. The prediction was subsequently employed as a statistical test for the need to perform surgery. The CT splenic ranking system developed in this study helped confirm medical decisions to perform (or not perform) splenic exploratory surgery. The scoring system was particularly effective in prompting earlier surgical intervention which resulted in spleen-saving operation in those patients whose CT images did not uncover a hidden injury.

Magnetic resonance (MR) imaging is a reliable method for evaluating the mediastinum, a cavity between two main portions of an organ. The appearance of the thymus in the MR images changes dramatically with age. The shape of the thymus in children with thymic abnormalities is significantly different than in healthy children. The MR diagnosis of thymic masses or tumors is based on the presence of scattered or focal enlargement of the gland. Scattered enlargement occurs in cases of malignant or benign processes. Focal lesions can be solid or cystic, malignant or benign. MR imaging can differentiate cystic from solid tissue, although it is not always possible to distinguish among various cystic lesions. On MR images as on computed tomography (CT) measurement of the thymic dimensions can be used to differentiate between a normal and abnormal thymus. The results of this study suggest that MR imaging, which measures thymic thickness, is a sensitive discriminator of disease, although it is usually not needed for the recognition of thymic abnormalities. Qualitative assessment of thymic shape, margins, and signal intensity is usually sufficient to diagnose thymic disease. Measurement of thymic dimensions may help diagnose the degree to which a disease has infiltrated the thymus.

There are several ways to diagnose kidney problems using diagnostic imaging techniques such as computed tomography (CT) scanning. Because the kidneys can be injured or impaired for many reasons it is difficult to create a standard policy for imaging. Each case presents a unique set of factors. Urography is a technique that is easy to use and is often the first imaging technique chosen for kidney evaluation. CT scanning provides clear images and has many advantages over excretory urography. CT scanning is particularly reliable for identifying and locating the extent of kidney lacerations and identifying occluded blood vessels in the kidney. Additional important kidney imaging methods are: arteriography, ultrasound, nuclear medicine imaging, and magnetic resonance imaging (MRI). Imaging considerations are based on treatment needs, medical differences among patients and physician preference. Radiologists believe that CT scanning is the most effective means of examining impaired kidneys. MRI is an exciting imaging technique, but its uses in kidney imaging are not fully defined.

Incudostapedial articulation (the point where the incus and stapes bones of the middle ear are joined) was evaluated by computed tomography (CT) imaging in 15 patients with a disruption in the connection at the point where the incus and stapes bones are joined. Incudostapedial disruptions result in hearing deficits. In ten of the cases inflammation was the cause of disruption, while the remaining five cases were due to trauma. The incus is known to be vulnerable to disruption, but the exact mechanism leading to disruption is not known. The study concludes that CT images of both inflammatory and traumatic incudostapedial disruptions are an excellent means of diagnosing problems in this area of the ear.

Primary biliary cirrhosis is a rare disease of the small bile ducts within the liver. Computed tomography (CT) scanning was used to analyze lymphadenopathy (disease of the lymph nodes) in 21 patients. Research demonstrated that these findings may be misinterpreted as lymphoma (tissue growth in the lymphatic system) or metastatic disease (movement of diseased cells, especially cancer, from one part of the body to another). The results show that lymphadenopathy is a common CT finding in primary biliary cirrhosis. Two unexpected findings were reported: lymphadenopathy in the paracardiac (near the heart) region and mesenteric lymphadenopathy, which occurred in 19 percent of the patients studied (the mesentery is a peritoneal fold around the greater part of the small intestine, connecting the intestine to the rear abdominal wall). The CT finding of enlarged lymph nodes in the small bile ducts within the liver (hepatic portal) suggests a diagnosis of metastatic cancer or lymphoma, particularly in patients with elevated levels of liver enzymes.

Hyperplasia (excessive growth of normal cells) of the curved portion (coronoid) of the jawbone (mandible) is a rare cause of restricted jaw movement. A computed tomography (CT) imaging study of three patients with this jaw abnormality was conducted. The first signs of coronoid process hyperplasia typically begin during puberty; the main symptom is painless limitation of jaw movement. The cause of this condition is not known. Surgical removal of the excess areas of cell growth is the accepted treatment for the disorder. In the three cases of coronoid process hyperplasia studied, CT (conducted with the patient's mouth open) clearly and easily demonstrated the abnormal coronoid process and the changes that occurred at the inner aspect of the zygomatic arch (the formation of the jaw bone at the side of the cheeks). CT scanning was an effective and fast means of establishing the diagnosis of hyperplasia of the jawbone in patients with symptoms of this disorder.

Magnetic resonance spectroscopy (MRS) is used to determine the biochemical structure of human body tissue. It relies on signals emitted by the hydrogen atom, abundant in the human body. MRS studies have demonstrated tissue metabolism in both animals and human subjects. Until recently, most MRS studies showed how muscle activity works by measuring alterations in adenosine triphosphate (ATP). Traditionally, new magnetic resonance (MR) techniques have been applied to brain studies. MRS, which is a specialized application of the principles of MR technology, can be used to investigate how the brain works with respect to edema, oxygen depletion or hypoxia, and carbohydrate metabolism. Preliminary studies on brain activity, using MRS, suggest that different types of brain tumors exhibit different ways of using hydrogen. Widespread studies are currently underway to improve the diagnostic reliability of hydrogen MRS. It will be important to compare the accuracy of these findings with computed tomography (CT) studies, since CT evaluation of the brain has been used for some time. It is expected that spectroscopic imaging studies of brain tumors and other abnormalities will be used to obtain added metabolic information for tissue characterization. Although MR imaging is a powerful tool for the study of anatomy, function, blood flow, and perhaps even perfusion, it has not yet allowed direct detection of biochemical changes. MRS may be the improvement that will make MR a powerful tool for the evaluation of these biochemical aspects of brain activity.