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Biomedical subjects

J A Patton

Publications and source records attributed to J A Patton.

At least 55 records · Page 3Linked to original sources
PubMed1985

Clinical magnetic resonance imaging with nuclear medicine correlation.

The current role of magnetic resonance imaging (MRI) in different organ systems is discussed and compared to nuclear medicine and to other available clinical diagnostic modalities. The value of optimizing radiofrequency pulse sequence selection to provide additional tissue characterization is also described. The results of nuclear medicine and MRI studies in 56 patients are compared to evaluate the clinical diagnostic contribution of each imaging modality for various pathological processes. In addition, the state-of-the-art MRI systems and future development in MRI technology with its potential contribution is defined.

Abdomen↗
PubMed1985

Prediction of benignancy of the solitary "cold" thyroid nodule by fluorescent scanning.

A quantitative x-ray fluorescent scanning technique has been used routinely to determine iodine content ratios (ICR) of nodule to normal thyroid tissue in patients with solitary "cold" thyroid nodules. A study of 150 patients with histological diagnoses has shown that an ICR above 0.60 is an excellent indicator of benignancy with a sensitivity of 63% and a specificity of 99%. This technique, in conjunction with careful clinical judgment, can be used to identify those patients that are at low risk for malignancy and can probably undergo conservative clinical management.

Americium↗
PubMed1984

Glucoheptonate measurement of differential renal function.

In previous studies using dogs whose renal function was rendered asymmetric by unilateral infarction or partial ureteral obstruction, the efficacy of technetium-99m diethylenetriamine pentaacetic acid and dimercaptosuccinic acid in the measurement of differential renal function was demonstrated. The present study was undertaken to determine if technetium-99m glucoheptonate could also be used to quantitate differential renal function in these conditions. Five dogs with partial ureteral obstruction, 4 with segmental infarction and 2 with ipsilateral combination of both were studied. Seven to 10 days following these interventions the animals were given a bolus injection of 10 mCi Tc-99m glucoheptonate. This was acquired in the posterior projection on a minicomputer at 2 seconds/frame for 3 minutes. Static images were obtained anteriorly and posteriorly between 3 and 5 hours postinjection. The following day iothalamate and creatinine clearances were measured by ureteral catheterization. There was good correlation between differential function calculated from the 1 to 3 minute portion of the bolus study and that determined by the ureteral catheter studies, r greater than 0.99. Correlations based on the static images were less satisfactory due to pelvic retention in the obstructed animals, r = 0.73. We conclude that technetium-99m glucoheptonate may be used to determine differential renal function.

Animals↗
PubMed1984

Evaluation of renal masses by MR imaging.

Magnetic resonance (MR) imaging was performed in 20 subjects, 10 of whom had benign or malignant renal masses, and 10 were normal volunteers. The purpose of the study was to evaluate the ability of MR to provide significant diagnostic information in the management of renal mass lesions. Ten normal patients were included to supply baseline data. Different pulse sequences were used and their contribution to the diagnosis was evaluated. The emphasis has been placed on evaluating MR against the pathological diagnosis rather than other imaging modalities.

Adenocarcinoma↗
PubMed1984

Current perspectives on medical imaging.

Advances in biomedical technology have expanded the potential of medical imaging. Selected aspects of developments in sonography, nuclear medicine, nuclear magnetic resonance and digital imaging are addressed, stressing the wide scope permitted by these newer modalities.

Angiography↗
PubMed1984

Evaluation of intrathoracic goiter with I-123 scintigraphy and nuclear magnetic resonance imaging.

Iodine-123 thyroid scintigraphy allows the diagnosis of a functioning retrosternal goiter in a patient with a mediastinal mass. The case report of a 60-yr-old lady demonstrates this. The correlative values of nuclear magnetic resonance imaging and thyroid scintigraphy in the initial evaluation and continued management of patients with thyroid mediastinal mass are presented. In addition, this observation demonstrates the ability of nuclear magnetic resonance to identify retrosternal thyroid tissue. This may obviate the need for TCT evaluation, which involves both ionizing radiation and iodinated contrast enhancement.

Female↗
PubMed1983

Comparison of supine, upright, and prone positions for liver scans.

We compared liver scan interpretations based on anterior images obtained in the upright, prone, and supine positions. Receiver-operating-characteristic curves were generated for three well trained observers. Results showed that reading the three different views together was more accurate than the reading of any individual image. Furthermore, interpretations based on either the prone or upright view were superior to those using the supine view alone. The prone and upright views should be used more often in liver scanning.

Humans↗
PubMed1983

Digital subtraction angiography: limitations for the detection of pulmonary embolism.

Perfusion lung scanning, magnification pulmonary arteriography, and digital subtraction angiography (DSA) were performed prior to and following Gelfoam embolization of selected pulmonary arteries in eight canines. The sites of embolization were identified in 75% of perfusion lung scans, in 93% of magnification pulmonary arteriograms, in 75% of arterial phase DSA studies, and 100% of parenchymal phase DSA examinations. With technological advances, DSA has the potential to become the examination of choice for the evaluation of patients suspected of having pulmonary emboli.

Angiography↗
PubMed1982

Simultaneous bi-plane digital video-fluoroscopy.

A prototype system for digital subtraction angiography that is capable of acquiring digitized video-fluoroscopic images simultaneously from both anterior and lateral imaging chains of a conventional bi-plane system was developed. A hardware module that takes images from both the anterior and lateral video cameras and displays them both on a single video image prior to digitization was designed and constructed. The three-dimensional information provided by a digital bi-plane images should improve the accuracy of cardiac-ventricular function studies. In addition, bi-plane imaging should reduce the need for additional views and the associated repeated injections of contrast media. With this technique, digital bi-plane imaging can be carried out with commercially available systems without duplication of the digital-processing chain.

Animals↗
PubMed1982

The effects of gating delays on ejection estimates: concise communication.

We have examined the effects of gating delays on the left-ventricular ejection fraction as measured by gated blood-pool studies. Patients with normal ventricular function were shown to have greater errors introduced by gate delays than those with poor function. The magnitude of the error depends on the shape of the ventricular time-activity curve. Actual delay measurements were performed on several commercial gates.

Cardiac Output↗
PubMed1981

The potential impact of digital radiography (DR) on the speciality of nuclear medicine.

Digital radiography is a reasonably economical system that helps diagnostic imaging physicians to develop increasingly less-invasive procedures, obtain maximal information at a given dose and increase the flexibility and convenience involved with diagnostic workups. The range of applications of DR has not been fully established at this time. Comparison of its properties with those of conventional nuclear medicine may suggest areas of potential application. Compared to nuclear medicine techniques, DR in general provides improved anatomical resolution, improved contrast resolution, sometimes equivalent functional information, and decreased imaging time. On the other hand, some functional nuclear medicine studies provide information not available by DR; including the gallium scan, bone scan, hepatic-biliary scan, and lung scan. Therefore, nuclear medicine procedures will be complimentary in some instances to digital radiography procedures and competitive in others. The proper roles of each modality in various clinical settings await future detailed and comprehensive efficacy studies.

Animals↗
PubMed1980

Imaging techniques for the radioimmunodetection of cancer.

Problems in the radioimmunodetection of cancer typically involve small lesions having low object contrast. As such, the imaging device utilized must have a high spatial resolution as well as high detection efficiency. In addition, the imaging device must be interfaced to a computer system to allow data manipulation to include background substraction, contrast enhancement, and organ subtraction techniques to be used. While the conventional scintillation camera is the most widely used imaging device in conventional nuclear medicine imaging procedures, this system does not provide adequate imaging performance for radioimmunodetection of cancer. This is true since these devices typically do not provide adequate object contrast when detecting small lesions in the presence of moderately high background activity. The Pho/Con (Searle Radiographics) is a tomographic imaging device which, when interfaced to a computer system, is capable of providing adequate lesion detection for this specialized procedure. The newest version of this tomographic imaging system has a spatial resolution and a detector efficiency which are comparable to those of the conventional scintillation camera. The system has the added advantage of relatively constant high-spatial-resolution performance as well as high sensitivity over a wide range of depths. In addition, the imaging process involves a rectilinear scanning motion which results in inherently uniform response in each plane of interest. These combined properties result in high detection of small lesions in cases where the object contrast is extremely low. These inherent imaging properties when combined with the improved contrast provided with computer manipulation of data make this system ideal for radioimmunodetection problems. In this paper, the importance of spatial resolution, count density, lesion size, and object contrast are discussed in relation to the detectability of lesions in radioimmunodetection of cancer. In addition, the characteristics of the Pho/Con and its advantages in lesion detection are described.

Computers↗
PubMed1978

Simultaneous emission and fluorescent scanning of the thyroid.

A comparison study of lithium-drifted silicon [Si(Li)] and high purity germanium (HpGe) was performed to explore the feasibility of replacing the current Si(Li) detector with the higher-efficiency HpGe detector. The improved efficiency of HpGe permits the use of collimators with higher resolution, which results in improved image quality over that achieved by the current Si(Li) system in use at Vanderbilt with an overall reduction in sensitivity of 29%. Since a 10 mm thick HpGe detector is about 75% efficient at 140 keV, the added advantage exists of simultaneously (a) imaging the stable-iodine distribution within the thyroid by x-ray fluorescence, and (b) the distribution of administered radiotracers such as [99mTc] pertechnetate. This comparison study shows that HpGe can compete with Si(Li) in overall detector efficiency, with the added benefits of better collimation to improve spatial resolution plus the simultaneous imaging of Tc-99m, all at the same equipment cost.

Germanium↗