Biomedical subjects

G Gamsu

Publications and source records attributed to G Gamsu.

At least 91 records · Page 5Linked to original sources

PubMed1986

Bronchoalveolar lavage as the exclusive diagnostic modality for Pneumocystis carinii pneumonia. A prospective study among patients with acquired immunodeficiency syndrome.

Pneumocystis carinii pneumonia (PCP) is the most common life-threatening opportunistic infection among patients with the acquired immunodeficiency syndrome (AIDS). Because retrospective studies suggested that bronchoalveolar lavage (BAL) compared favorably to lung biopsy in the diagnosis of PCP, we prospectively evaluated the utility of BAL in 40 consecutive patients with AIDS or risk of AIDS who presented with respiratory complaints. The BAL revealed P carinii in 36 of 42 episodes of pneumonia (86 percent) among 40 patients. Clinical follow-up of the six patients whose BAL was negative for PCP suggested only one possible false negative BAL for PCP. Therefore, BAL detected PCP in 36 of 37 patients for a sensitivity of 97 percent. BAL detected cytomegalovirus in 15 of 38 patients, as well as Mycobacterium avium-intracellulare and Cryptococcus (each in one patient). By virtue of accuracy and lack of morbidity demonstrated in our study, BAL should supplant lung biopsy techniques in the evaluation of AIDS patients with pulmonary symptoms.

Acquired Immunodeficiency Syndrome↗

PubMed1986

Evaluation of a chest phantom for CT nodule densitometry.

The characteristics of a chest phantom used for CT nodule densitometry were determined by use of a GE CT 9800 scanner (General Electric, Milwaukee, WI). The supplied reference rods were scanned in different positions within the lung fields of the phantom and with varied chest wall thicknesses. The liver/spleen inserts were added. The CT attenuation values of different-size rods and their mineral content were also tested. The size of the standard rod is the major determinant of its CT number, which varied from 1 to 83 H. The standard rods contained no measurable calcium or other mineral. Position-dependent variability in CT numbers was relatively small with the GE CT 9800 scanner. The simulated chest wall additions and liver/spleen inserts produced only small increases in CT density. We conclude that the GE CT 9800 scanner, as an example of one of the newer CT scanners, shows improved operating characteristics for pulmonary nodule densitometry. Nodule densitometry should be further evaluated with simplified phantoms.

Densitometry↗

PubMed1985

Pulmonary nodules: detection using magnetic resonance and computed tomography.

Detection of pulmonary nodules using spin-echo magnetic resonance (MR) imaging was compared with detection using computed tomography (CT). Of the 25 patients studied independently by two radiologists, no lung nodules were detected in 11 (CT or MR), ten had a single nodule, and four had multiple nodules. The lesions not seen using CT or MR were less than 1.3 cm in diameter. The greater spatial resolution of CT enabled better detection of nodules close to the diaphragm, the pleura, or to each other, whereas the better contrast resolution of MR enabled the detection of several nodules close to blood vessels. With MR, nodules were best seen on images with long repetition times (2.0 sec). Most pulmonary nodules are seen using both CT and MR. CT generally enables the detection of more small nodules than MR does, and some low-density nodules near blood vessels are better displayed using MR.

Adolescent↗

PubMed1985

Bronchogenic carcinoma: staging with MR compared with staging with CT and surgery.

Thirty-three patients suspected of having bronchogenic carcinoma were studied prospectively using magnetic resonance (MR). In this group, 30 underwent examination with computed tomography (CT), 15 underwent thoracotomy, six had mediastinal biopsy procedures performed, and eight underwent bronchoscopy. MR studies, which included transaxial spin-echo imaging (TR, 0.5 and 2.0 sec; TE, 28 and 56 msec) of all patients and sagittal or coronal imaging of 18, were performed without knowledge of CT findings, using only plain radiographs as a guide. CT and MR studies were interpreted separately. CT and MR provided comparable information regarding the presence and size of mediastinal lymph nodes. MR better discriminated mediastinal nodes from vascular structures. However, in two of 11 patients who had multiple mediastinal lymph nodes that were normal in size at CT examination and surgery, MR suggested a confluent abnormal mass, probably because of its poorer spatial resolution. MR was superior to CT in showing enlarged hilar lymph nodes, but CT was better for demonstrating bronchial abnormalities. In three of four patients who had a proved hilar mass with distal obstructive pneumonia, MR (TR, 2.0 sec) helped distinguish between the mass and collapsed lung.

Adult↗

PubMed1985

Paratracheal lymphadenopathy: radiographic findings and correlation with CT.

Possible signs of paratracheal lymphadenopathy on the posteroanterior (PA) chest radiograph were assessed in 98 patients and correlated with computed tomography (CT). The nodes were normal in size in 62 patients and enlarged (greater than 15 mm) in 36. Among the latter group, widening of the right paratracheal stripe was seen in 11 (31%) and enlargement of the azygos node in 15 (42%). While the lateral contour of the superior vena cava (SVC) was convex in 46 patients (47%), 81 (83%) had an increased density in the region of the SVC. When all four parameters were combined, lymphadenopathy could be detected on the PA view in 87 patients (89%). CT demonstrated that the enlarged nodes were anterolateral rather than directly lateral to the trachea and also immediately posterior to the SVC, explaining the findings on the PA radiograph.

Adolescent↗

PubMed1985

Pneumocystis carinii pneumonia radiographically simulating tuberculosis.

Eight immunocompromised patients presented with upper lobe infiltrates that radiographically simulated tuberculosis. Bilateral lobar consolidation was present in 5, and apical or posterior segmental consolidation was present in 3. Pneumocystis carinii was diagnosed in 7 patients from material obtained at bronchoscopy after sputum stained for mycobacteria had been negative. In the eighth patient, sputum submitted for cytologic evaluation demonstrated P. carinii. The 7 patients surviving this episode of pneumonia responded clinically and radiographically to specific therapy directed against P. carinii. Predominant upper lobe involvement has not been previously emphasized as a pattern of P. carinii pneumonia but should be considered in immunocompromised patients.

Adult↗

PubMed1985

Relationship of pleural effusions to pulmonary hemodynamics in patients with congestive heart failure.

On the basis of both experimental and clinical studies it is not clear whether left, right, or biventricular heart failure are necessary for the formation of pleural effusions. In order to study the relationship of pulmonary hemodynamics and the presence of pleural effusions in patients with congestive heart failure, we prospectively evaluated 37 patients admitted to the coronary care unit with congestive heart failure secondary to ischemic heart disease or a cardiomyopathy. We used real-time ultrasonography to document the presence of pleural effusions. We found that 19 of the 37 patients with heart failure had pleural effusions. Mean pulmonary artery wedge pressure was 24.1 +/- 1.3 mmHg (SE) in the 19 patients with pleural effusions versus 17.2 +/- 1.5 mmHg (SE) (p less than 0.001) in the 18 patients without pleural effusions. Pulmonary artery pressure was also higher in patients with pleural effusions with a mean value of 38.0 +/- 1.5 mmHg (SE) versus 30.7 +/- 2.1 mmHg (SE) (p less than 0.05) in the patients without pleural effusions. In contrast, mean right atrial pressure was not different between patients with pleural effusions (12.6 +/- 1.5 mmHg) (SE) versus those without pleural effusions (9.8 +/- 1.0 mmHg) (SE) (p = NS). In addition, there was no difference in cardiac output, pulmonary vascular resistance, or total protein concentrations between patients with and without pleural effusions. We conclude that, in patients with congestive heart failure, an elevated left atrial pressure is closely correlated with the presence of pleural effusions, while concurrent elevation of right atrial pressure is not associated with the presence of pleural effusions.

Blood Pressure↗

PubMed1985

Nonbronchoscopic bronchoalveolar lavage for the diagnosis for Pneumocystis carinii pneumonia in the acquired immunodeficiency syndrome.

We compared conventional bronchoscopic transbronchial biopsy (TBB) and bronchoalveolar lavage (BAL) with non-bronchoscopic bronchoalveolar lavage (NB-BAL) in nine patients with acquired immunodeficiency syndrome (AIDS) and bilateral lung infiltrates. NB-BAL was carried out with a control-tipped reusable catheter. In each patient, bronchoscopic procedures were performed in the right lung, followed immediately by NB-BAL in the left lung. The specimens obtained by NB-BAL confirmed the presence of P carinii pneumonia in seven of eight patients in whom the diagnosis was established by TBB or BAL. Viral cultures of NB-BAL specimens yielded cytomegalovirus (CMV) in four of five subjects with evidence of CMV via bronchoscopic technique, including two instances in which CMV was not detected by BAL. Complications were limited to right-sided pneumothorax attributable to TBB. Accuracy of NB-BAL appears to be comparable to that of conventional bronchoscopic approaches in the diagnosis of AIDS-related pulmonary infection with P carinii or CMV. NB-BAL may be a safer and more economical alternative to TBB and BAL in the diagnosis of pulmonary opportunistic infections.

Acquired Immunodeficiency Syndrome↗

PubMed1985

Subcarinal lymph node enlargement: radiographic findings and CT correlation.

Detection of subcarinal lymph node enlargement on the posteroanterior chest radiograph was assessed in 90 patients who also had computed tomography (CT). Sixty of the 90 patients had normal-sized and 30 had enlarged (greater than 15 mm diameter) subcarinal lymph nodes on CT. An abnormality in the contour of the azygoesophageal recess interface was present on plain radiographs in only 23% of patients with lymphadenopathy; increased subcarinal opacity was present in 40%. The external surface of the medial wall of the right main-stem bronchus and bronchus intermedius was visible in 87% of patients with normal-sized lymph nodes but in only 27% of patients with lymphadenopathy. CT showed that the medial wall of the right main-stem and intermediate bronchi normally is delineated laterally by air within the bronchus and medially by lung or subcarinal fat. Nonvisualization may be due to replacement of lung or fat by enlarged nodes or tumor and may be helpful in assessing patients with suspected subcarinal adenopathy.

Adult↗

PubMed1985

Magnetic resonance imaging of the superior pericardial recesses.

The potential of magnetic resonance imaging (MRI) of the superior pericardial space was evaluated in a retrospective review of MR images of 46 subjects. The superior pericardial space and its two recesses had low signal intensity. The preaortic recess was demonstrated on 82% of nongated transverse scans. The retroaortic recess was demonstrated on 67% of nongated transverse scans. Generally, both recesses were shown with an even higher frequency on ECG-gated and ECG-permutation-gated scans. Knowledge of the location and typical appearance of these pericardial recesses should preclude mistaking them on MRI for a vascular structure, aortic dissection, or an atherosclerotic plaque or mural thrombus within the ascending aorta.

Adolescent↗

PubMed1984

Nuclear magnetic resonance of pulmonary arteriovenous fistula: effects of flow.

Nuclear magnetic resonance (NMR) imaging can be of value in distinguishing vascular and nonvascular lesions in the lung and mediastinum, in that rapidly flowing blood results in little or no NMR signal. We wish to report a patient having a pulmonary arteriovenous fistula evaluated using physiological studies, dynamic computed tomography, and spin-echo NMR. On the NMR images, the fistula was invisible because of rapid flow through its lumen.

Aged↗

PubMed1984

Magnetic resonance imaging of the neck. Part I: Normal anatomy.

Magnetic resonance (MR) images of the neck were obtained in 24 patients using a specially designed radio-frequency coil, standard and high-resolution imaging techniques, and a variety of spin echo and inversion recovery pulse sequences. Cervical vascular structures were more easily identified with MR than with CT because of the inherent contrast of flowing blood. The laryngeal skeleton, paralaryngeal tissues, trachea, thyroid, esophagus, and muscles were identified in all cases by MR using morphologic criteria comparable with CT criteria. The spatial resolution of high-resolution MR was slightly inferior to high-resolution CT. However, streak artifacts due to motion and x-ray beam hardening often limited CT, but did not affect MR. Anatomic resolution was best using high-resolution spin echo images obtained with TR = 2.0 seconds and TE = 28 msec because this imaging technique offered excellent contrast between normal tissues and had the highest signal-to-noise ratio. With further improvements in spatial resolution MR is likely to become an important technique for imaging the neck.

Adolescent↗

PubMed1984

Magnetic resonance imaging of the neck. Part II: Pathologic findings.

Magnetic resonance (MR) images of the neck were obtained in 14 patients with thyroid, parathyroid, lymph node, or laryngeal lesions. Tumors and lymph nodes were more easily differentiated from muscle and blood vessels with MR than with CT because of the superior soft tissue contrast of MR. Tissue characterization allowed MR differentiation of thyroid nodules, thyroid cysts, and parathyroid tumors from normal thyroid tissue; however, nonspecifically increased T1 and T2 relaxation times overlapped for a variety of neoplastic and inflammatory conditions. Thyroid cyst fluid had the greatest water content and longest T1 and T2 times of all tissues studied. Parathyroid hyperplasia could not be differentiated from parathyroid adenoma; however, parathyroid tumors had slightly longer T1 and T2 times than thyroid nodules or lymph nodes. With further experience, MR tissue characterization may become a useful technique for evaluating neck masses.

Adolescent↗

PubMed1984

Multisection sagittal and coronal magnetic resonance imaging of the mediastinum and hila. Work in progress.

Sagittal or coronal thoracic magnetic resonance (MR) images were obtained in 7 individuals - 4 normal subjects and 3 patients with thoracic masses. In 2 of the abnormal cases, sagittal or coronal MR provided significant anatomic information that was either less evident or invisible on transaxial MR or computed tomographic (CT) images or CT reformations. In the third abnormal patient, a pretracheal lymph node was more clearly seen on transaxial images than on coronal images.

Adult↗

PubMed1984

Magnetic resonance imaging of benign mediastinal masses.

Eight patients who had benign mediastinal masses underwent CT and magnetic resonance (MR) imaging. The intensity difference between mass and surrounding mediastinal fat was greater on MR than CT images. Although the masses were clearly identified with both modalities, delineation of a mass from surrounding mediastinal structures was better with CT. Heterogeneity on CT and MR images was a prominent feature of most larger benign mediastinal masses, although this should not be considered indicative of benignity. These benign mediastinal masses were best demonstrated on MR images obtained using a long TR and short TE. In general, the MR studies provided information comparable to but not identical to that of CT scanning. The viewing of mediastinal masses using a variety of TR and TE imaging parameters appeared to be an important aspect of the MR studies.

Adenoma↗

PubMed1984

EKG-gated digital subtraction angiography in the detection of pulmonary emboli.

Detection of pulmonary emboli was investigated using electrocardiographically gated (EKG-gated) intravenous digital subtraction angiography (DSA) in 6 anesthetized and paralyzed dogs. Six autologous blood clots were introduced into the internal jugular vein of each dog and both conventional pulmonary angiography and EKG-gated DSA performed in frontal and oblique projections. When two observers scored any definite or equivocal embolus as positive, sensitivity was 82.1% for one and 92.9% for the other; the respective positive predictive values (PPV) were 88.5% and 65%. When only definite emboli were considered positive, sensitivity was 75% for one observer and 71.4% for the other; PPV was 100% for both. The authors conclude that DSA can demonstrate individual emboli with good sensitivity and excellent precision. If several emboli are present, EKG-gated DSA should prove highly accurate; however, care must be taken because overinterpretation is more likely with DSA than with conventional pulmonary angiography.

Angiography↗

PubMed1984

Magnetic resonance imaging of the normal and abnormal pulmonary hila.

Magnetic resonance (MR) images of the hila were reviewed in 25 normal subjects and 12 patients with unilateral or bilateral hilar masses. On spin echo MR images in normal patients, collections of soft tissue large enough to be confused with an abnormally enlarged lymph node were seen in three locations. In patients with a hilar mass, the mass was differentiated from hilar vasculature more easily using MR than contrast-enhanced CT. In five of these patients, hilar lymph nodes approximately 1 cm in diameter were easily seen using MR, but were difficult or impossible to appreciate prospectively on CT. However, because the spatial resolution of MR is inferior to that of CT, bronchi were difficult to evaluate using MR. In general, images obtained with a short TR (0.5 sec) provided the best definition of mediastinal extension of the hilar mass, and images with a longer TR (1.5 to 2.0 sec) provided a better signal-to-noise ratio and showed increased signal strength from hilar masses. Electrocardiographic-gated images showed better resolution of hilar structures but may not be necessary for large masses.

Adult↗

PubMed1984

Experimental pulmonary emboli detected using magnetic resonance.

Experimental pulmonary emboli that were labelled with non-magnetic barium threads and produced using aminocaproic acid were introduced into the internal jugular veins of five dogs. Transverse axial magnetic resonance (MR) images (0.35 T, 15 MHz) and CT scans (2.0 or 4.8 seconds, G.E. 9800 or 8800 scanner) were obtained from the lung apex to base in each animal. The MR images were gated to the cardiac cycle, and spin echo techniques were used (TR = gated to the cardiac cycle; TE = 28 and 56 msec). Nineteen sites of embolism were determined from the CT scans. Two observers, who had no knowledge of the number or position of the emboli, individually assessed the MR images and marked the sites of emboli on clear acetate overlays. Each observer detected 12 of 19 emboli (63%) and each had one false positive result. Of the 19 emboli, six were central or parahilar and 13 were in the outer two thirds of the lungs. Three (first observer) or four (second observer) of the seven false negative results were central. In retrospect, two central emboli were mistaken for hilar fat. One peripheral embolus was not visible, even in retrospect. The potential for MR to demonstrate relatively small pulmonary emboli has been shown. Clinical trials in patients seem warranted.

Animals↗