PubMed Health⌕ Search

Biomedical subjects

P H Nath

Publications and source records attributed to P H Nath.

At least 19 recordsLinked to original sources
PubMed1989

A comparison of dual-energy digital radiography and screen-film imaging in the detection of subtle interstitial pulmonary disease.

An ROC study is described which compares the performance of three types of images--conventional screen-film, single-energy digital and dual energy bone cancelled (soft tissue) digital--in detecting subtle interstitial pulmonary disease. Marginally detectable nodular and reticulonodular patterns (12 different patterns of each) were superimposed over the lungs of a frozen human chest phantom to simulate the clinical situation. The digital images were formatted on film at full size (ie, 35 cm X 43 cm). A total of 156 images (52 of each type, of which 28 were normal and 24 had simulated pathology) were used in the study and read by five experienced chest radiologists. Using a paired t-test, the areas under the individual ROC curves were compared for three combinations of images--single-energy digital and conventional, soft tissue digital and conventional, and soft tissue and single-energy digital. No statistically significant difference was observed between the conventional and single-energy digital images. The readers performed better with both conventional and single-energy digital images than with the soft tissue digital images at statistically significant levels (P = 0.05 for conventional vs. soft tissue digital and P = 0.02 for single-energy digital vs. soft tissue digital). The results suggest that there is no advantage in employing dual-energy soft tissue images to assist in diagnosing interstitial disease in the clinical setting. They also suggest that spatial resolution requirements are less demanding in digital chest systems that obtain scatter-free images than in digital systems utilizing conventional scatter control techniques.

Evaluation Studies as Topic↗
PubMed1989

Acquired diseases of aberrant subclavian arteries.

The anatomic, clinical, and radiologic findings of aberrant subclavian arteries (ASAs) are well known. Acquired diseases such as aneurysms, dissections, or stenosis can complicate these anomalies. We propose that these complications are a result of atherosclerosis caused by abnormal turbulence around the ASA. Comparisons of computed tomographic and angiographic measurements of subclavian arteries in adults with and without arch anomalies and angiographic measurements of ASAs in children show that ASAs dilate in older patients. We describe six patients with acquired diseases of ASAs or the aorta adjacent to the ASA. Aneurysms, aortic dissections, and stenosis were each found in two patients. Problems in the radiologic diagnosis and clinical management of these diseases are emphasized. Radiologists should be cognizant of the significance of ASAs in patients with aortic aneurysms and dissections.

Adult↗
PubMed1988

Detection of emphysema with computed tomography. Correlation with pulmonary function tests and chest radiography.

We studied 60 male patients who had concurrent chest films (CXR), computed tomography scans (CT) and pulmonary function tests (PFT) to assess the sensitivity of CT and conventional films in detecting emphysema compared with PFT. We also sought to determine whether emphysema could be diagnosed by CT in patients with normal pulmonary function. Using a method similar to that proposed by Bergin, we scored the severity of emphysema depicted by CT, and using arterial deficiency and bullae as criteria, we estimated the degree of emphysema on CXR. There was a significant inverse correlation between CT scores for emphysema and percentage predicted values of DLco/VA (r = -0.650), FEV1 (r = -0.552), and FVC (r = -0.409), (P less than 0.001). A significant but smaller correlation also was noted with the CXR scores and percentage predicted: DLco/VA (r = -0.564), FEV1 (r = -0.454), and FVC (r = -0.355), (P less than 0.005). When decreased diffusion capacity and airway obstruction were used as functional criteria of emphysema, CT was as sensitive as PFT and more sensitive than CXR in detecting emphysema (96% vs. 68%). There was CT evidence of emphysema in 69% (24/35) of patients who did not have functional findings of emphysema. In 12 pathologic specimens available for review, 11 had emphysema by CT and pathologic examination; one patient had centrilobular emphysema undetected by CT. We conclude that CT is as sensitive as PFT in detecting emphysema and more sensitive than conventional radiography. CT may be more sensitive than PFT in detecting mild emphysema.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Percutaneous fine needle aspiration in the diagnosis and management of mediastinal cysts in adults.

Management of asymptomatic mediastinal cysts in adults is controversial. In the past, these cysts were excised primarily to establish a diagnosis. Presently, computerized tomography (CT) of the chest can diagnose the majority of mediastinal cysts, based on their smooth contour and low density; however, CT diagnosis of a mediastinal cyst based on density can be erroneous. In six patients, we established the diagnosis of mediastinal cyst by percutaneous needle biopsy (PNB) without complication. In four of the patients, PNB was done as an outpatient procedure. Follow-up in five patients ranged from three months to three years, with no increase in the size of the cyst; in the sixth patient, surgical excision showed a hygroma. Thus, diagnosis of a mediastinal cyst can be safely confirmed by PNB. We suggest that these asymptomatic patients can be followed up without the need for surgical excision.

Adult↗
PubMed1988

Atrial septal defect in older adults: atypical radiographic appearances.

Atrial septal defect (ASD) is the most common congenital cardiac anomaly manifested in adulthood. Clinical and radiographic features are well defined in patients less than 30 years of age. In older patients, however, the clinical symptoms are often atypical, and the auscultatory findings may be misleading. The radiographic manifestations in older patients have not been well described. In the current study, of 70 patients over the age of 50 years with proved ASD, 21 (30%) had atypical radiographic features, including apparently normal vascularity, left atrial enlargement, pulmonary venous hypertension, and pulmonary edema. In a control group of 70 younger patients with ASD, only 5.7% had atypical findings. The development of pulmonary venous hypertension and pulmonary edema in older patients was associated with smaller defects and a higher prevalence of mitral valve disease, left ventricular dysfunction, and pulmonary arterial hypertension than seen in older patients with typical radiographic findings.

Age Factors↗
PubMed1987

Pericardial cyst diagnosed by two-dimensional echocardiography and computed tomography in a newborn.

A one-day-old full-term female infant with massive "cardiomegaly" developed marked respiratory distress soon after birth. The two-dimensional (2D) echocardiogram demonstrated a 4 X 5-cm cystic mass adjacent to the left ventricular free wall. Computed tomography (CT) confirmed the presence and dimension of the cyst and CT number indicated the fluid within the cyst to be serous. A pericardial cyst was successfully removed at thoracotomy. Two-dimensional echocardiography and CT, both noninvasive procedures, are fully adequate tools in the diagnosis of pericardial cysts in the neonate, so that invasive investigations may be avoided.

Echocardiography↗
PubMed1987

Nonbronchial systemic collateral arteries: significance in percutaneous embolotherapy for hemoptysis.

Twenty patients with massive or recurrent hemoptysis underwent percutaneous transcatheter embolotherapy between 1979 and 1986 for the following diseases: cavitary aspergillosis (n = 4); cystic fibrosis (n = 4); tuberculosis (n = 3); bronchogenic carcinoma (n = 3); bronchiectasis (n = 3); small cell lung carcinoma 6 years after irradiation (n = 1); congenital heart disease, after Glenn and Blalock anastomoses (n = 1); and unknown interstitial disease (n = 1). Bronchial arteries were embolized in all but one patient. In nine patients (45%) nonbronchial systemic collateral arteries contributed significantly to areas of pathologic pulmonary tissue and frequently were the major arterial supply. These nonbronchial systemic collaterals included branches of the subclavian and axillary arteries (n = 7), intercostal arteries (n = 5), and phrenic arteries (n = 3) and accounted for 59.5% of the total number of arteries embolized. Recognition and occlusion of nonbronchial systemic collaterals providing blood to hypervascular pulmonary lesions is essential for successful percutaneous embolotherapy of hemoptysis.

Adolescent↗
PubMed1986

The role of computed tomography in acute and subacute mediastinitis.

Acute and subacute infection in the mediastinum, though rare, is associated with a substantial mortality which increases with delay in diagnosis. The conventional radiographic and computed tomographic studies of 14 patients with proven infective mediastinitis were reviewed in an attempt to identify their relative roles in its diagnosis. Signs of infection demonstrated by computed tomography (CT) included abscess formation, mediastinal masses, soft tissue collections contiguous with other infected compartments and areas of diffuse mediastinal infiltration with fat plane loss without prominent lymphadenopathy. The anatomy and extent of the infection was well delineated by CT in all patients. In nine cases this information affected clinical management, facilitating percutaneous drainage of the abscess in three. In five patients, information from CT did not alter clinical management.

Acute Disease↗
PubMed1985

Overriding atrioventricular valves. An angiographic-anatomical correlate.

An analysis of 6 patients with overriding atrioventricular valve was performed in order to correlate the anatomic and angiographic features of this malformation. The atrial arrangement was usual (situs solitus) in each patient. The ventricular chambers were normally related in 4 and the mirror image of normal in 2. The atrioventricular connexion was concordant in parallel fashion in 4, discordant in 1 and double inlet left ventricle in 1 heart. In 2 of 4 hearts with concordant atrioventricular connexion, the right atrioventricular valve (tricuspid) overrode the septum and connected partially to the left ventricle. In 2, the left atrioventricular valve (mitral) overrode the septum and partially connected with the right ventricle. One heart with discordant atrioventricular connexion had its right atrioventricular valve (mitral) overriding the septum. The remaining heart with double inlet left ventricle had an overriding left atrioventricular valve. Each overriding atrioventricular valve had its "septal" leaflet (the one committed to the contralateral ventricle) divided into 2 segments by a large cleft. Ventricular septal defects at different locations were present in all cases. The ventriculoarterial connexion was double outlet right ventricle in 5 patients and was discordant in 1. Malalignment of the atrial and ventricular septa was present to some degree in all cases. This was well depicted on ventriculograms in four chamber view in those with an overriding tricuspid valve. It was not detected in those with an overriding mitral valve. The displaced leaflets of the overriding and/or stradding valve had a vertical motion on cineangiograms similar to those observed in atrioventricular septal defects. Abnormal morphology and motion of the septal leaflet of the overriding atrioventricular valve and malalignment of the atrial and ventricular septal structures were the most important angiographic findings in this series.

Adolescent↗
PubMed1984

Pulmonary arteriovenous fistulas occluded by percutaneous introduction of coil springs.

Between July 1980 and July 1983, we occluded 30 pulmonary arteriovenous fistulas (PAVFs) in four patients by percutaneous placement of coil springs. All patients had significant right-to-left shunts and hypoxemia. One presented with recurrent cerebral abscesses following bilateral thoracotomy and lobectomy. The technique requires advancement of the catheter superselectively into the feeding artery just proximal to the fistula. Occlusion at this site preserves the maximum amount of functioning pulmonary parenchyma. Frequently more than one coil spring is required for occlusion. In our experience, the coil spring is a safe, effective, economical vaso-occlusive device for management of PAVFs.

Adult↗
PubMed1984

Pneumonia in bone marrow transplant patients.

The radiographic, pathologic, and clinical features of 22 episodes of pneumonia in 18 bone marrow transplant recipients were analyzed retrospectively. These pneumonias could be divided into three diagnostic categories: (1) a transient form of nonspecific interstitial pneumonia resembling pulmonary edema in radiographic appearance occurred in five patients during the first 2 weeks after transplantation; (2) a fatal, progressive form of interstitial pneumonia began from 2 weeks to several months after bone marrow transplantation in seven patients; and (3) airspace pneumonias occurred in nine patients within 2 months of transplantation and were uniformly fatal. While the temporal and radiographic presentation of transient early interstitial pneumonia is often characteristic and may not require biopsy for diagnosis, the airspace and progressive interstitial pneumonias affecting bone marrow transplant recipients present variable patterns that are often radiographically indistinguishable. The direct pulmonary toxicity of high-dose total-body irradiation and chemotherapy may be contributory in producing both the early transient and later progressive forms of nonspecific interstitial pneumonia.

Bone Marrow Transplantation↗
PubMed1984

Tetralogy of Fallot with atrioventricular canal. An angiographic study.

Tetralogy of Fallot associated with atrioventricular (AV) canal is a well-recognized cardiac malformation; its surgical repair carries a high mortality, which is related partly to the complexity of the defect and partly to incomplete diagnosis. Hence an accurate preoperative diagnosis is essential. This communication describes the angiographic features observed in 17 patients with tetralogy of Fallot and AV canal with emphasis on the morphology of the right AV valve as seen during the right ventriculogram. A complete anatomic diagnosis can be consistently made from right and left ventriculograms performed in axial projections.

Adolescent↗
PubMed1982

Systemic-to-pulmonary collaterals in pathological states: a review.

Abnormal systemic-to-pulmonary-artery anastomoses can exist in many pathological conditions and result in a left-to-right shunt. Three such conditions are (a) congenital abnormalities, e.g., pulmonary vein atresia, (b) acquired states, e.g., chronic bronchiectasis, and (c) post-surgical states, e.g., a Mustard procedure for complete transposition. Regardless of the etiology, the anastomosis and resulting shunt produce increased oxygen saturation in the ipsilateral pulmonary artery. Four cases are presented, with emphasis on the angiographic and hemodynamic findings.

Adult↗