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Biomedical subjects

R G Levitt

Publications and source records attributed to R G Levitt.

At least 37 records · Page 2Linked to original sources
PubMed1985

Pleural and chest wall invasion in bronchogenic carcinoma: CT evaluation.

CT scans of 47 patients who had peripheral bronchogenic carcinoma contiguous to the pleural surface and who had undergone thoracotomy were retrospectively reviewed. The CT features of the primary neoplasm that were analyzed included the angle and amount of contact with the adjacent pleural surface, associated pleural thickening, fat plane between the tumor and chest wall, rib destruction, and chest wall mass. CT was of limited predictive value in separating those patients who had parietal pleural/chest wall involvement from those who did not. The combination of two or three CT findings (obtuse angle, greater than 3 cm contact with pleural surface, associated pleural thickening) resulted in a sensitivity of 87% and a specificity of 59%. The clinical symptom of focal chest pain, while not as sensitive (67%) as CT, was much more specific (94%) for parietal pleura/chest wall invasion.

Adenocarcinoma↗
PubMed1985

Magnetic resonance imaging of mediastinal and hilar masses: comparison with CT.

Magnetic resonance imaging (MRI) was compared to computed tomography (CT) of the mediastinum and/or hila in 37 patients with bronchogenic carcinoma (35 unresectable for cure) and 11 patients with other masses. Spin-echo pulse sequences using a short pulse repetition rate (TR) and short echo delay (TE) were most helpful for detection of abnormal soft-tissue mediastinal and hilar masses. The accuracy of MRI and CT in staging bronchogenic carcinoma for curative resectability/nonresectability was comparable. CT staged 35 of 37 cases appropriately, while MRI correctly staged 36 of 37 cases. Several pitfalls in MRI evaluation of the mediastinum were identified. By MRI the esophagus may be misinterpreted as an enlarged retrotracheal lymph node unless serial scans are studied. Scattered calcifications in enlarged mediastinal and hilar lymph nodes due to old granulomatous disease are not detectable by MRI. Small adjacent lymph nodes shown individually by CT may appear as a single enlarged lymph node by MRI due to partial-volume averaging. Small lung nodules may be undetected by MRI due to respiratory motion and partial-volume averaging. Certain patients are unsuitable for MR scanning. Because of the requirement for patient selection and the identified pitfalls of MRI, CT remains the radiologic procedure of choice in the staging of patients with bronchogenic carcinoma and the evaluation of other mediastinal and hilar masses at present. However, because of the ability to show blood vessels without an intravascular contrast agent, MRI is useful in evaluating patients with potential contrast allergy and solving diagnostic problems not solved by CT.

Calcinosis↗
PubMed1985

Magnetic resonance imaging of fibrosing mediastinitis.

Magnetic resonance imaging (MRI) was performed in seven patients with fibrosing mediastinitis. Comparison was made in each case to standard chest radiography and computed tomography (CT). Angiography was performed in three cases. Although MRI and CT were found to be equivalent in defining the extent of adenopathy, CT was superior at demonstrating calcifications, often important in making the diagnosis of fibrosing mediastinitis. MRI, however, offered complementary information, particularly in assessing vascular patency without the need for intravenous contrast media. On T2-weighted images, the adenopathy associated with fibrosing mediastinitis was noted to be of relatively low signal intensity, possibly indicating its benign nature.

Adult↗
PubMed1984

Computed tomography of Tietze syndrome.

Six patients with clinical features suggestive of Tietze syndrome had a thoracic computed tomographic (CT) examination following a normal plain film or tomographic examination (or both) of the affected costochondral junction. A chest wall mass was excluded in all six patients. The CT findings included enlargement of the costal cartilage at the site of complaint (two patients), ventral angulation of the involved costal cartilage (two patients), and normal anatomy of the costochondral junction (two patients). Exclusion of a chest wall mass by CT may obviate the need for operative intervention.

Adolescent↗
PubMed1984

NMR imaging of pulmonary arteriovenous fistulae .

The nuclear magnetic resonance (NMR) imaging of pulmonary arteriovenous fistulae is reported, and the value of NMR in separating vascular from nonvascular lesions in the lung and mediastinum is discussed.

Adult↗
PubMed1984

Fatty infiltration of the liver: demonstration by proton spectroscopic imaging. Preliminary observations.

Two normal volunteers and three patients with CT evidence of fatty infiltration of the liver (two nonuniform, one diffuse) were studied to determine whether magnetic resonance imaging using a pulse sequence designed to differentiate fat and water could be used to detect fatty infiltration of the liver in human beings. The magnetic resonance technique used a modified spin echo technique (simple proton spectroscopic imaging) that was designed specifically to exploit the difference in the rate of precession between the protons in a water molecule and the protons in a fatty acid molecule. Images were obtained using in-phase and opposed techniques and were added or subtracted in order to obtain pure water and pure fat images. Quantitative data showed that fatty liver can be separated from normal liver using the spin echo technique, and that the opposed image of the proton spectroscopic technique is more sensitive to small changes in hepatic fatty content than in-phase images with any echo time.

Electron Spin Resonance Spectroscopy↗
PubMed1984

Magnetic resonance imaging of abdominal and pelvic lymphadenopathy.

The authors report their experience with magnetic resonance imaging (MR) in 20 patients with CT-proved lymphadenopathy of the abdomen and pelvis. Signal intensity from abnormal nodes was intermediate between fat and muscle (T1 longer than fat and muscle; T2 equal to or slightly shorter than fat but longer than muscle) and was shown best in the spin-echo mode with a TR of 900 msec. and a TE of 30 msec. Abnormal nodes were identified by their increased size and other morphological changes rather than by tissue characteristics established by signal intensity information. Lymphadenopathy due to lymphoma could not be differentiated from that due to metastases. MR detected all lymphadenopathy originally documented by CT and in addition easily distinguished blood vessels from lymph nodes; on the other hand, CT offered better spatial resolution and could be completed in less time.

Abdomen↗
PubMed1984

Peripheral pulmonary infiltrates in sarcoidosis.

The chest roentgenograms are described in eight patients with sarcoidosis who demonstrated a peripheral distribution of pulmonary infiltrates quite similar in appearance to that classically observed in eosinophilic pneumonia. The presence of mediastinal/hilar lymph node enlargement (eight patients), a nodular component to the infiltrate (four patients), an often asymptomatic presentation (four patients), and absence of blood eosinophilia (eight patients) should suggest the correct diagnosis.

Adult↗
PubMed1984

CT of primary germ-cell tumors of the mediastinum.

Primary mediastinal germ-cell tumors are rare neoplasms that usually occur in young men. Computed tomographic (CT) scans in four patients demonstrated large anterior mediastinal masses obliterating fat planes and extending inferiorly along the left mediastinal border. Nonseminomatous tumors contained areas of near-water density (cyst formation and/or necrosis) as well as soft-tissue density. Although CT features may suggest the diagnosis before histologic confirmation, the most important roles of CT are evaluation of extent of disease and monitoring response to therapy.

Adolescent↗
PubMed1984

Computed tomography of abdominal carcinoid tumors.

Computed tomographic (CT) scans were obtained in 20 patients with primary and/or metastatic abdominal carcinoid tumors. The primary tumors were seen rarely on CT. Mesenteric involvement was seen in eight of the 20 patients, usually as a soft-tissue mass surrounded by fat and radiating soft-tissue strands. Enlarged retroperitoneal lymph nodes were seen in seven patients, but rarely were they the only manifestation of intraabdominal disease. The most common finding was liver metastases (13 of 20 patients). CT is helpful in evaluating the extent of tumor before surgical exploration and in following the progression of disease once the diagnosis has been established.

Adult↗
PubMed1984

Magnetic resonance imaging of abdominal aortic aneurysms.

Magnetic resonance imaging (MRI) was performed in 20 patients with radiologically or surgically proven abdominal aortic aneurysms using a Siemens Magnetom scanner with a 0.35-T superconductive magnet. On MRI, rapidly flowing blood emits little or no signal and appears black; stagnant blood, turbulent flow, and atheromatous plaques produce signals of various intensities and are imaged as light to medium gray. Of nine patients who underwent surgical repair, MRI correctly demonstrated the origin of the aortic aneurysm in nine and accurately determined the status of the iliac arteries in eight. In two patients in whom intravenous contrast administration was contraindicated, MRI provided the correct diagnosis of a mycotic pseudoaneurysm in one and clearly distinguished the iliac arteries from the surrounding fibrosis in the other. Of 11 patients who did not have surgical repair, MRI findings correlated well with other radiologic studies. MRI was found to be more reliable than sonography in determining the relation between the aneurysm and the renal arteries as well as the status of the iliac arteries. Despite these advantages, the authors still advocate sonography as the screening procedure of choice in patients with suspected abdominal aortic aneurysms because of its lower cost and east of performance. MRI should be reserved for patients who have had unsuccessful or equivocal sonographic examinations.

Aged↗
PubMed1983

Computed tomographic features of biliary obstruction.

A retrospective review of CT scans in 69 consecutive patients with proven biliary obstruction due to both malignant and benign causes was performed to define and differentiate CT changes. Abrupt termination of a dilated extrahepatic biliary duct was characteristic of a malignant process in the absence of a mass. Gradual tapering of a dilated duct was specific for benign disease. Other findings, such as degree of intra- or extrahepatic duct dilatation and presence or absence of a dilated pancreatic duct were not reliable in distinguishing benign from malignant causes. The authors also found CT to be accurate in detecting common duct stones with a sensitivity exceeding 80%.

Adult↗
PubMed1982

Computed tomography of the pancreas: three second scanning versus 18 second scanning.

Diagnostic accuracy of pancreatic computed tomography (CT) using a 3 s scanner was compared to our previously published results using an 18 s scanner. Technically unsuccessful examinations have decreased to less than 1%. Pancreatic masses were detected prospectively in 83% of patients with pancreatic carcinoma and retrospectively in all such patients. False negative diagnoses of normal pancreas in proven pancreatic carcinoma were reduced fourfold down to 6%. False positive diagnoses of pancreatic carcinoma remained less than 1% but were not significantly reduced compared to our second year's experience using an 18 s scanner. Interpretation errors and errors due to limitations of CT as a diagnostic technique are discussed.

Acute Disease↗
PubMed1982

Computed tomography of the abnormal thymus.

Computed tomography (CT) should be the imaging method of choice following plain chest radiographs when a suspected thymic abnormality requires further evaluation. Based upon a six-year experience, including the evaluation of 25 patients with thymic pathology, CT was found useful in suggesting or excluding a diagnosis of thymoma and in distinguishing thymic hyperplasia from thymoma in patients with myasthenia gravis. The thickness of the thymic lobes determined by CT was found to be a more accurate indicator of infiltrative disease (thymic hyperplasia and lymphoma) than the width. CT was helpful in differentiating benign thymic cysts from solid tumors, and in defining the extent of a thymic neoplasm. On occasion, CT may suggest the specific histologic nature of a thymic lesion.

Adolescent↗
PubMed1982

Computed tomography in the preoperative evaluation of bronchogenic carcinoma.

Preoperative determination of the extent of bronchogenic carcinoma at presentation was assessed by CT using a 4th generation scanner with a 3-second scan time in 98 patients whose disease was later surgically staged. Prospective CT interpretations correctly staged 33 of 35 (94%) resectable lesions, and disease in 41 of 45 (91%) patients who had lesions that were not resectable for cure. No definite opinion was rendered on the scans of the remaining 18 patients. Retrospectively analysis using slightly modified criteria resulted in a correct prediction of resectability in 28 of 30 (93%) patients (scans showed a normal mediastinum with no lymph node larger than 1 cm in diameter), and nonresectability for cure in 34 of 34 (100%) patients (scans showed either direct extension of the primary neoplasm into the mediastinum or mediastinal lymph-node enlargement greater than 2 cm in diameter). However, scans of 34 of 98 (35%) patients showed inconclusive findings (mediastinal lymph-nodes with 1-cm to 2-cm diameters, neoplasms abutting but not definitely invading the mediastinum, pleural or pericardial thickening, or additional noncalcified nodules).

Adenocarcinoma↗
PubMed1982

Clinical utility of CT in pediatric retroperitoneal disease: 5 years experience.

The utility of computed tomography (CT) in evaluation of the retroperitoneum was assessed in 54 pediatric patients and compared with that of conventional radiography. In 20 patients (group 1) with an abnormality on conventional radiographs, CT improved diagnostic understanding in 17 and affected management in four patients. In 31 patients (group 2) with clinical suspicion of a mass but normal abdominal radiographs, CT contributed diagnostic information in seven and had a beneficial effect on therapy in five patients. CT contributed diagnostic information in three other patients evaluated for trauma (group 3). CT was most useful in defining the extent of a lesion in group 1 and in demonstrating absence of a suspected mass in group 2.

Abscess↗