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Biomedical subjects

F W Smith

Publications and source records attributed to F W Smith.

At least 109 records · Page 6Linked to original sources
PubMed1988

A comparison of Tc-99m HM-PAO and I-123 IMP cerebral SPECT images in Alzheimer's disease and multi-infarct dementia.

SPECT images of the brain can be obtained using either 123I labelled amines or 99mTc-hexamethylpropyleneamineoxime (HM-PAO). Both materials produce images which are blood flow dominated and so appear similar in normal subjects, although the respective mechanisms of uptake are not yet finally established. It seems likely, however, that the different mechanisms of uptake are responsible for recent reports of some differences seen in images obtained with the two types of agent in patients with cerebral pathology, mainly cerebrovascular disease. In this study, 12 demented patients, 6 with dementia of the Alzheimer type (DAT) and 6 with multi infarct dementia (MID), were imaged with 123I-isopropylamphetamine (IMP) and 99mTc-HM-PAO and the images compared. Significantly more lesions were seen with IMP than HM-PAO (P less than 0.02); out of a possible 120 sites, 41 lesions were seen with IMP compared to 28 with HM-PAO, 23 being seen with both agents. However, it is concluded that either agent can be used for the differential diagnosis of dementia, a task for which the new cerebral blood flow agents seem well suited.

Aged↗
PubMed1988

A postmortem correlation of four techniques of assessment of osteoporosis with force of bone compression.

Prosected vertebrae and phalanges from 32 cadavera were examined using noninvasive methods commonly used for assessment of osteoporosis. Bone measures were then compared with a strength variable obtained by mechanically crushing or breaking the bones. All of the phalangeal density assessment techniques were found to be significantly correlated with the bone strength. The highest correlations were between bone mineral content and strength. In vertebral samples (cubes with 2 cm sides), bone mineral content corrected for bone width (BMC/BW) was significantly correlated with the force at the first deviation from linearity. Correlations between the computed tomography number and bone strength were negligible. Bone strength of the vertebrae was significantly correlated to that of the fingers. Photon absorptometric (SPA) measurements of the vertebrae correlated significantly with corresponding measures of the phalanges. BMC/BW appeared as the first or second variable selected as a predictor of bone strength in the multiple regression analysis. Throughout this entire study, BMC or BMC/BW were the only variables that were consistently related to the strength variables.

Aged↗
PubMed1988

Musculo-skeletal magnetic resonance imaging using inversion recovery pulse sequences at 0.08 T.

The potential of magnetic resonance imaging (MRI) for the assessment of musculo-skeletal tumours has until recently been underestimated. Most reports in the literature describe the MRI appearances of musculo-skeletal tumours using spin-echo pulse sequences with high field, superconductive magnets. This paper describes the use of inversion recovery pulse sequences using a low field resistive magnet for the study of musculo-skeletal disorders. Thirty patients who had either radiological evidence of a bone tumour or a soft tissue mass were studied by low field MRI and inversion recovery, and calculated T1 images compared with the tissue histology of the mass. It has been found that inversion recovery images display the size and extent of both bone and soft tissue tumours and that the use of coronal and axial images enable clear display of the relationship of bone and soft tissue tumours to the major blood vessels, muscle and cortical bone.

Adolescent↗
PubMed1988

The use of technetium-99m-HM-PAO in the assessment of patients with dementia and other neuropsychiatric conditions.

One hundred fourteen patients suffering from neuropsychiatric conditions have been studied using 99mTc-labeled hexamethylpropyleneamine oxime (HM-PAO) and single photon emission computed tomography (SPECT). Ninety-one patients had a firm clinical diagnosis while 23 were examined without knowledge of the clinical diagnosis. Of the 91 patients, 51 were suffering from dementia, 25 multi-infarct type and 26 Alzheimer's disease. In 19 of the Alzheimer's patients, a characteristic pattern of decreased perfusion in the parieto-occipital regions was demonstrated while those with multi-infarct type showed varying degrees of irregular uptake in the cerebral cortex. These appearances are similar to those shown with positron emission tomography (PET) and we believe that HM-PAO will provide a widely available method for identifying patients with Alzheimer's disease. Twenty-nine patients were suffering from diseases involving the basal ganglia. Fifteen patients with Parkinson's disease showed no significant abnormality in basal ganglia uptake, while 7 or 8 patients with Huntington's disease who had full examinations showed decreased uptake in the caudate nuclei. Similarly, four of six patients with other basal ganglia diseases showed impaired uptake by basal ganglia, and it is concluded that HM-PAO may be useful for the diagnosis and management of this type of patient. Twenty-three patients received HM-PAO imaging as part of their diagnostic work-up; in 19 of them, detailed follow-up was obtained, which indicated that in 7 cases the result of the HM-PAO scan altered the clinical diagnosis and in 9 cases resulted in a change in management. In the remaining 13 cases, the study was found to be helpful in confirming the diagnosis.

Adult↗
PubMed1988

Imaging of cerebral blood flow markers in Huntington's disease using single photon emission computed tomography.

Single photon emission computed tomography (SPECT) imaging of six Huntington's disease patients revealed a striking reduction in regional uptake of cerebral blood flow markers in vivo. Similar changes were found in one patient with "early stage" disease. The findings are compared with parallel magnetic resonance imaging (MRI) studies, and in one case, results of postmortem examination.

Adult↗
PubMed1988

Use of nebulised saline and nebulised terbutaline as an adjunct to chest physiotherapy.

To determine whether sputum clearance is increased by using nebulised saline or terbutaline as an adjunct to chest physiotherapy, a radioaerosol method (using technetium-99m labelled human albumin millimicrospheres) was employed in eight patients with stable bronchiectasis on four occasions, for comparison of sputum clearance with four different regimens. These were: control, with the patient resting in an upright position; chest physiotherapy, by the forced expiration technique with postural drainage; and chest physiotherapy following five minutes' inhalation of either nebulised normal saline or nebulised terbutaline 5 mg. Use of both nebulised saline and nebulised terbutaline immediately before chest physiotherapy gave a significantly greater yield of sputum than did physiotherapy alone, and terbutaline also significantly increased radioaerosol clearance from the whole lung and from regions of interest. The mechanism is unclear, but this method may provide a simple way of increasing the efficacy of conventional chest physiotherapy.

Adult↗
PubMed1988

Brain imaging and treatment response in spasmodic torticollis.

A patient with spasms of the neck, occurring when he turned his head to the left, responded to treatment with benzhexol. Cerebral blood flow imaging demonstrated reduced uptake in the right corpus striatum compared with the left. The study demonstrates the presence of an abnormality in the basal ganglia; it also illustrates response to drug treatment. Cerebral blood flow imaging may be useful in the detection of basal ganglia abnormalities in spasmodic torticollis and assist in the selection of cases which should be targeted for treatment with drugs.

Adult↗
PubMed1988

Sub-cutaneous fat thickness measured by magnetic resonance imaging, ultrasound, and calipers.

Sub-cutaneous fat thickness was measured at 12 sites on the body surface of 24 males and 26 females using magnetic resonance imaging (MRI), skinfold calipers, and A-mode ultrasound. The mean of the 12 fat thickness measurements and individual site thicknesses were compared between individuals using analysis of variance. In males, the mean thicknesses for ultrasound and calipers were similar (P greater than 0.05) but both were less than the MRI (P less than 0.001). MRI and ultrasound were similar in females but less than calipers (P less than 0.001). A good between-subject correlation was found between all three methods in the males but only the calipers and MRI were well correlated in females. Within-subject correlations are poor for all measures and in both sexes. Factor loadings for a varimax rotation of two principal components indicate that the fat is distributed in 1 of 2 patterns: either principally on the trunk or on the limbs. The principal component analysis and the result of canonical correlations obtained from the factor loadings confirm the findings of the analysis of variance, in that a general level of fatness is measurable by all three methods over a range of subjects. However, the pattern of fat thicknesses measured over a number of specific sites by one method of measurement is unlikely to be duplicated by either of the other two methods on the same individual.

Adipose Tissue↗
PubMed1988

Technetium 99m HMPAO scanning in patients with subarachnoid haemorrhage: a preliminary study.

Technetium 99m hexamethylpropylene amine oxime (HMPAO) is an agent which, when injected intravenously, gives images which reflect cerebral blood flow. Seven patients who had suffered subarachnoid haemorrhage were examined by cerebral angiography and by 99Tcm HMPAO scanning. The two studies were compared and in six cases there was evidence of decreased cerebral perfusion in relation to the ruptured aneurysm causing the subarachnoid haemorrhage. In one case no cause for the haemorrhage was demonstrated angiographically, and the HMPAO study was normal. In two of the six cases, spasm of the cerebral artery distal to the ruptured aneurysm was seen angiographically and it appears that 99Tcm HMPAO scanning does not correlate with gross arterial spasm but reflects smaller degrees of cerebral underperfusion not demonstrable by angiography. The results demonstrate a relationship between local decreased cerebral perfusion and ruptured cerebral aneurysm and may be of use in determining which aneurysm has bled in patients who have more than one aneurysm demonstrated angiographically.

Female↗
PubMed1988

The study of regional cerebral blood flow in stroke patients using technetium 99m HMPAO.

Seventeen patients who had suffered a stroke in the previous 72 h have been studied using technetium 99m hexamethyl propylene amine oxime (HMPAO) to assess cerebral blood flow. Comparison of the scan appearances and clinical signs were made in all cases. Twelve of the patients had a repeat HMPAO scan 14 days later, together with further clinical assessment. Good correlation between the size and site of perfusion deficit and the clinical signs was found in 14 of the patients. When the results of the 12 patients who had repeat scans were examined at 14 days the correlation between the scan and the clinical signs was less accurate and it seems unlikely that the assessment of the size of cerebral infarction as demonstrated by an HMPAO scan will provide an accurate prognostic sign. Three of the patients, all of whom had suffered right hemiplegia and were dysphasic, had regions of increased uptake adjacent to the area of ischaemia and non deteriorated clinically; it is thought that this sign may represent hyperperfusion around infarction and indicates a fair prognosis. In patients suffering from transient neurological symptoms, the use of HMPAO may be useful by excluding the presence of other cerebral disease.

Aged↗
PubMed1988

Magnetic resonance imaging of the parotid glands using inversion-recovery sequences at 0.08 T.

One hundred and eight examinations on 103 patients with suspected disease of the salivary glands were studied using a 0.08 T resistive magnet and inversion-recovery pulse sequences. Sixty-eight patients who had a mass lesion within a salivary gland later had surgery, and specimens were obtained for histological diagnosis. The remaining 35 patients were diagnosed on clinical grounds. In all cases the clinical findings were compared with the appearances on magnetic resonance imaging (MRI). The use of inversion-recovery pulse sequences allowed accurate localization of all tumour masses and, because of the clarity with which blood vessels were displayed, the precise relationship of any parotid mass to the retromandibular vessels and hence the facial nerve was possible. Whilst MRI did not display any pathognomonic features to allow the differentiation of malignant cell types or the differentiation of invasive malignant tumours from chronic inflammatory disease, it was possible to differentiate parotitis from Mikulicz's disease and to diagnose cysts and pleomorphic adenomas by their appearances on MRI.

Cysts↗
PubMed1988

Magnetic resonance image synthesis from an interleaved saturation recovery/inversion recovery sequence.

An interleaved saturation recovery/inversion recovery (SR/IR) pulse sequence allows the sign of the IR signal to be retained even if images are formed from the magnitude of the two-dimensional complex Fourier transforms of the raw data. Synthesis of images by a linear combination of SR and signed IR pixel values has proved a valuable method of relaxation time (T1) contrast manipulation without the need to re-image the slice. Linear combination has also allowed IR images with a wide range of time-to-inversion (TI) values to be synthesized from an SR/IR pair obtained with TI = 200 ms and time-to-recovery (TR) = 1000 ms, thus avoiding the need for computationally intensive calculations based on complicated relaxation equations.

Computer Simulation↗
PubMed1988

Magnetic resonance imaging of the orbits using a binocular surface coil.

Sixty subjects, including 12 normal volunteers, have been studied using the Aberdeen 0.08 T magnetic resonance imager. A wide range of pathological conditions, including both ocular and and orbital disease, have been examined using a specialized binocular surface coil. The images produced using this coil are superior to those made with a head coil and have the advantage of demonstrating both eyes simultaneously. Each patient has been studied using a pulse sequence combining alternate saturation-recovery and inversion-recovery pulses. The resultant short time-to-inversion inversion-recovery and saturation-recovery images have been shown to be accurate in demonstrating the normal anatomy of the globe and orbit and for the demonstration of a wide range of disease states.

Abscess↗
PubMed1988

Technetium-99m HMPAO imaging in patients with basal ganglia disease.

Technetium 99m hexamethylpropylene-amine oxime (HMPAO) is trapped by cerebral grey matter and the basal ganglia on its first pass through the brain. To assess its potential for studying patients with diseases of the basal ganglia, a study of 15 normal volunteers and 32 patients with known or suspected basal ganglia disease have been investigated. Sixteen patients with idiopathic Parkinson's disease showed no abnormality of the basal ganglia and varying degrees of cerebral underperfusion consistent with their intellectual status. Eight patients with Huntington's chorea showed a characteristic pattern of reduced or absent caudate nucleus uptake. Patients with diseases affecting the basal ganglia, such as Fahr's disease, Wilson's disease and hemibalismus had varying degrees of basal ganglia underperfusion as demonstrated by an HMPAO scan. We believe that this new radiopharmaceutical for the demonstration of cerebral blood flow shows significant potential for the diagnosis and management of patients with basal ganglia disease.

Adult↗
PubMed1988

Frequency of isolated proximal colonic polyps among patients referred for colonoscopy.

The American Cancer Society now advocates screening asymptomatic populations over the age of 40 to 50 years for colonic malignancy. It is possible, however, that fecal occult blood testing and sigmoidoscopy to 60 cm would fail to identify patients with adenomatous polyps located only in the proximal colon. The purpose of this study was to determine how many patients without polyps in the distal 60 cm of the colon would have more proximal lesions. Ninety-eight consecutive patients with positive fecal blood test results or suspicious barium enema results were studied, using the assumption that if they had been seen six months earlier, when asymptomatic, they would have been candidates for screening examination. Forty-one (42%) of 98 patients had adenomatous polyps or cancer, and 15 (37%) of these patients had isolated proximal lesions. The polyp detection rate from 0 to 60 cm was significantly less than the detection rate for a full colonoscopy (27% vs 42%). We conclude that isolated proximal colonic polyps may be common.

Adenocarcinoma↗