Monday, January 9th, 2006.

Der Radiologe. 2006 Jan 5; [Epub ahead of print]. [Link]

R. Eibel1, 3 Contact Information, P. Herzog1, O. Dietrich1, C. Rieger2, H. Ostermann2, M. Reiser1 und S. O. Schoenberg1

1. Institut für Klinische Radiologie, Ludwig-Maximilians-Universität München,
2. Abteilung für Hämatologie/Onkologie, Klinikum Großhadern, Ludwig-Maximilians-Universität München,
3. Institut für Klinische Radiologie, Klinikum Innenstadt, Ludwig-Maximilians-Universität München, Ziemssenstraße 1, 80336 München

Abstract

Magnetic resonance imaging (MRI) of the lung is challenging because of substantial drawbacks. However, lung pathologies that are associated with increased attenuation values in CT enhance visualization in MRI: proton density is increased and tissue-air interfaces, resulting in susceptibility artifacts, are reduced in pneumonia, pneumonitis, edema, and carcinoma. On the other hand, many lung diseases result in shortness of breath, so that patients cannot hold their breath for long periods. Therefore, fast imaging techniques are required which should also allow for high spatial resolution so that small lesions can be detected. Calcifications and air pockets within lesions are not readily recognized with MRI. Thin section CT is standard for the diagnosis of pneumonia. With parallel imaging techniques, MRI examination of the lungs can be performed with short periods of breath holding, which allow for sub-centimeter resolution in the z-axis. Especially for follow-up examinations in immunocompromised patients and, in some instances, for the staging of malignant diseases (malignant pleural mesothelioma, lung cancer, respectively), MRI is very promising and may contribute to a decrease in the radiation exposure of the patients.

Glossary

staging

the process of finding out whether cancer has spread and if so, how far. There is more than one system for staging. The TNM system, described below, is one used often. The TNM system for staging gives three key pieces of information: T refers to the size of the Tumor N describes how far the cancer has spread to nearby Nodes M shows whether the cancer has spread (Metastasized) to other organs of the body Letters or numbers after the T, N, and M give more details about each of these factors. To make this information somewhat clearer, the TNM descriptions can be grouped together into a simpler set of stages, labeled with Roman numerals. In general, the lower the number, the less the cancer has spread. A higher number means a more serious cancer.

MRI

Stands for magnetic resonance imaging. A method of taking pictures of the inside of the body. Instead of using x-rays, MRI uses a powerful magnet and transmits radio waves through the body; the images appear on a computer screen as well as on film. Like x-rays, the procedure is physically painless, but some people find it psychologically uncomfortable to be in the small core of the MRI machine.

imaging

any method used to produce a picture of internal body structures. Some imaging methods used to detect cancer are x-rays (including mammograms and CT scans), magnetic resonance imaging (MRI), scintigraphy, and ultrasound.

edema

(eh-deem-uh) build-up of fluid in the tissues, causing swelling. Edema of the arm can occur after radical mastectomy, axillary dissection of lymph nodes, or radiation therapy.

diagnosis

identifying a disease by its signs or symptoms, and by using imaging procedures and laboratory findings. The earlier a diagnosis of cancer is made, the better the chance for long-term survival.

carcinoma

(car-sin-o-ma) a malignant tumor that begins in the lining layer (epithelial cells) of organs. At least 80% of all cancers are carcinomas.

cancer

malignancy; a group of diseases typified by abnormal, generally out-of-control, cell growth.

tissue

a collection of cells, united to perform a particular function.

mesothelioma

a tumor derived from mesothelial tissue, such as the peritoneum (lining the abdomen) or pleura (lining the lungs). More on mesothelioma.

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