Magnetic resonance imaging of the chest: a diagnostic comparison with computed tomography and hilar tomography

Magnetic resonance imaging in the evaluation of lung cancer

MRI is used most efficaciously in the evaluation of patients with bronchogenic carcinoma when employed as a tailored examination designed to answer specific questions relevant to patient management. CT continues to be used more generally in staging lung cancer when imaging beyond conventional chest radiography is required. Specific areas in which MRI can provide important and unique information (which may supplement a CT study) include the following: (1) evaluation of the local extent of superior sulcus tumors, and (2) distinction between stage IIIA (resectable) and stage IIIB (unresectable) tumors. Confirmation of tumor invasion of major mediastinal structures is necessary before depriving a patient of potential curative resection. MRI may contribute important information when CT findings are indefinite, particularly with regard to invasion of major cardiovascular structures (eg, superior vena cava, pulmonary artery, pericardium, and heart); invasion of the tracheal carina or bilateral involvement of main bronchi; and the presence of contralateral mediastinal or hilar lymphadenopathy. MRI should be considered as a primary imaging modality to evaluate central tumors in patients for whom intravenous contrast agents are contraindicated, and as a problem-solving modality when CT is inconclusive in the detection of a possible hilar or mediastinal mass. Other specific applications of MRI include the identification of tumor recurrence in the presence of radiation fibrosis, assessment of the extent of chest wall invasion of peripheral lung tumors, and the noninvasive characterization of adrenal masses. The scope of these MRI applications in patients with lung cancer may expand in the future with refinements in motion suppression techniques, implementation of ultrafast MRI (using variations of the echoplanar method), and further development of MRI spectroscopy and MRI contrast agents.

The penetrating aortic ulcer: pathologic manifestations, diagnosis, and management

The term "penetrating aortic ulcer" refers to an ulceration of an atheromatous plaque that extends deeply through the intima and into the aortic media. It may precipitate an intramedial dissection (usually localized) or may rupture into the adventitia to form a pseudoaneurysm. The typical patient with penetrating atheromatous aortic ulcer is elderly and has hypertension, atherosclerosis, and back or chest pain, but pulse deficit, stroke, aortic insufficiency, and compromise of a visceral vessel are not present. Classic aortic dissection and symptomatic thoracic aortic aneurysms are among possibilities in the differential diagnosis. Aortography demonstrates the presence of an aortic ulcer similar in appearance to gastric ulcers seen on barium examination; in addition, an intramural aortic hematoma may be present. Our experience with penetrating aortic ulcers in symptomatic patients indicates that conservative medical therapy leads to recurrence of symptoms and a need for surgical intervention. We present a case that illustrates the salient features of this distinct clinical entity.

The mediastinum in sagittal sectioning. Anatomy and magnetic resonance imaging (MRI)

Ten volunteers with a normal mediastinum were investigated by magnetic resonance using a 0.5 Tesla CGR imager with a supraconducting magnet. The reconstruction matrix consisted of a 256 X 256 grating for a field of the order of 420 mm, with a spatial resolution of 1.6 X 1.6 mm2. The sections, balanced in T1, were performed in synchronization with the ECG. The successive sagittal sections were correlated with sagittal sections made on a single embalmed frozen subject. The MRI and anatomic sections were made at 5 mm intervals and located in relation to the median sagittal plane of the mediastinum. Examples of structural variations, malformations or tumours studied in sagittal sections, and taken from investigation of over 170 patients, demonstrate the importance of this investigational technique.

Progress in the diagnosis and management of aortic dissection

A 36-year-old man sought medical attention because of pressure in his head and distention of the veins in his neck. Physical examination disclosed a murmur of aortic insufficiency, and a chest roentgenogram showed a dilated ascending aorta. Two-dimensional echocardiography and angiography demonstrated a large intimal tear in the ascending aorta and aortic insufficiency. The patient underwent a surgical procedure, which revealed that his symptoms were caused by compression of the superior vena cava by the dilated ascending aorta. The aortic dissection was successfully repaired by replacement of the aortic root with a composite graft into which the coronary ostia were reimplanted. After further assessment of the patient, including elicitation of a similar history in some paternal relatives, Marfan's syndrome was diagnosed. Physicians should be aware of the clinical manifestations, pathogenesis, and treatment of aortic dissection. With aggressive treatment, 60 to 90% of patients survived aortic dissection in 1985, whereas only 40 years ago, this entity was rarely recognized premortem or treated successfully.