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Biomedical subjects

K A Miles

Publications and source records attributed to K A Miles.

At least 55 records · Page 3Linked to original sources
PubMed1996

The significance of low grade right iliac fossa uptake on 99Tcm-HMPAO labelled white cell scans.

Technetium-99m HMPAO labelled white cell scanning is now an accepted method for assessing the activity of inflammatory bowel disease. However, false positive results have been demonstrated. This study was conducted to assess the significance of low grade uptake on 99Tcm-HMPAO labelled white cell scans in the right iliac fossa (RIF) in the context of possible inflammatory bowel disease (IBD). 32 patients over a period of 1 year had low grade RIF uptake as the predominant abnormality. 20 of these had no prior diagnosis of inflammatory bowel disease. Only one case in this group was subsequently diagnosed as having Crohn's disease. Nodular lymphoid hyperplasia (NLHP) and non-steroidal anti-inflammatory drugs (NSAIDs) were also associated with low grade RIF uptake. Possible explanations for these findings are discussed.

Adolescent↗
PubMed1995

Demonstration of popliteal artery entrapment on leg muscle scintigraphy with 99mTc MIBI and single photon emission tomography.

Popliteal artery entrapment is difficult to diagnose even at surgery. Early diagnosis is important as the prognosis is better if detected before the onset of complications. There is no sensitive method for the evaluation of this condition. We describe three cases detected by a new technique using 99mTc methoxy isobutyl isonitrile (MIBI) with single photon emission tomography. The scintigraphic features of entrapment and the advantage of MIBI leg scintigraphy over other methods are discussed.

Adult↗
PubMed1995

Transient splenic inhomogeneity with contrast-enhanced CT: mechanism and effect of liver disease.

PURPOSE: To use computed tomography (CT) and functional imaging to characterize the physiologic processes that result in transient splenic inhomogeneity during contrast material enhancement and determine their value in detection of diffuse liver disease. MATERIALS AND METHODS: CT scan data from nine control patients and 13 patients with diffuse liver disease were used to create functional images that displayed splenic perfusion and time to peak enhancement. A pixel-by-pixel analysis was used to create these images. RESULTS: Areas of early enhancement demonstrated higher perfusion and vice versa. In patients with liver disease, splenic perfusion values fell from 1.44 to 1.22 mL/min/mL in the areas that showed early enhancement and 1.24 to 0.89 mL/min/mL in the areas that showed late enhancement. As splenic perfusion values fell, the size of the regions that showed late enhancement increased. CONCLUSION: The combination of functional images and CT data has clarified the mechanism by which transient splenic inhomogeneity occurs and is of potential value in the detection of diffuse liver disease.

Adult↗
PubMed1995

Measurement of human pancreatic perfusion using dynamic computed tomography with perfusion imaging.

Absolute quantification of pancreatic perfusion in man has been extremely difficult to date. This paper describes a relatively simple application of dynamic computed tomography to provide perfusion imaging of the human pancreas. Values for perfusion in eight normal pancreases ranged between 1.25 and 1.66 ml min-1 ml-1 (mean: 1.52 ml min-1 ml-1). Increased perfusion values were present in a patient with an islet cell tumour (overall perfusion 2.11 ml min-1 ml-1) and a patient with Wilson's disease (3.43 ml min-1 ml-1). Pancreatic perfusion was reduced in a patient with diabetes (0.60 ml min-1 ml-1) and in a failing pancreatic transplant (0.97 ml min-1 ml-1). The combination of functional information and good spatial detail afforded by computed tomography (CT) perfusion imaging means the technique is well suited for the evaluation of the human pancreas. It is currently the only technique which allows non-invasive absolute quantification of pancreatic perfusion.

Adenoma, Islet Cell↗
PubMed1994

Slow metabolic deterioration towards diabetes in islet cell antibody positive patients with autoimmune polyendocrine disease.

We studied metabolic progression to IDDM in a cohort of adults who are ICA-positive and have associated autoimmune endocrine disease or circulating organ-specific autoantibodies (the Polyendocrine Study). Of the 186 individuals recruited 27 developed overt diabetes after a median follow-up of 4.5 years (range 0.4-12). Of these, eight patients did not require insulin treatment until at least 6 months after clinical diagnosis, with an interval of 1.8 years (1.2-5.7). An IVGTT was performed in 38 subjects and 23 had sequential studies. Of the initial 38 subjects six developed diabetes and only three showed a loss of FPIR to glucose (below the first percentile of a normal control group) before clinical onset of the disease. An additional three subjects showed a loss of the FPIR, and all still have normal glucose tolerance after median follow-up of 28 months (22-95). A "whole" or "mixed" pattern of islet cell staining was found in five of the six patients who developed diabetes and antibodies against an islet 37 k-antigen were detectable in four patients, all of whom required insulin soon after diagnosis. A beta-cell "selective" ICA staining pattern was seen in 14 of 17 subjects who did not develop diabetes and the "mixed" pattern in only three. None of this group had detectable 37 k-antibodies. We conclude that metabolic deterioration is slow in polyendocrine patients, and that the IVGTT has less prognostic significance in this group than in first degree relatives of patients with IDDM.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Indium-111 labelled leucocyte uptake in aortitis.

Inflammatory conditions of the aorta may present with non-specific clinical features, including unexplained fever. Indium-111 labelled leucocyte imaging may be performed in such patients to look for the presence of occult sepsis or to assess the activity of a known vasculitis. Of approximately 1100 patients to undergo leucocyte scintigraphy for these indications over a 5 year period, three had focal leucocyte uptake in the aorta. The final diagnoses were: (1) periaortitis in Wegener's granulomatosis; (2) aortic dissection in giant cell arteritis; and (3) streptococcal aortitis with impending rupture. In all three cases the uptake was initially not thought to be in the aorta, but in bowel, a paravertebral abscess and in the lumbar spine respectively. Further imaging with CT and MRI led to the correct diagnoses. As the aorta is a rare site of focal leucocyte uptake, errors in image interpretation are likely. The rapid diagnosis of inflammatory conditions of the aorta is essential, however, as they may be life-threatening if unrecognized; therefore awareness of the aorta as a potential site of uptake is important. Urgent referral for further imaging is imperative in these cases as a false or delayed diagnosis may lead to avoidable morbidity and mortality.

Aged↗
PubMed1994

Bone scintigraphy of hip prostheses. Can analysis of patterns of abnormality improve accuracy?

The patterns of abnormality (both site and intensity of uptake) on bone scintigraphy in 76 total hip replacements were studied and graded to determine whether specific patterns of abnormality were associated with greater accuracy in deciding the need for revision surgery. Patients were divided into three groups: 1) 45 hips were considered to have required surgery, 2) in 15 hips surgery was retrospectively considered unnecessary, and 3) 16 prostheses were painless. There was a trend for fewer abnormal sites and a lower intensity of abnormality from group 1 to group 3. By considering patterns of uptake, the specificity of bone scintigraphy could be improved from 65% to 95%, but at the expense of lower sensitivity, falling from 90% to 75%. The most accurate criteria for determining the need for revision surgery (sensitivity 88%, specificity 85%) were increased uptake at the tip or a total scintigraphy score of greater than 3.

Hip↗
PubMed1994

Scintigraphic appearances in patients with pulmonary infection and lung scintigrams of intermediate or low probability for pulmonary embolism.

Out of 294 patients with lung scintigrams of low or intermediate probability for pulmonary embolism, the appearances in 54 patients with a final diagnosis of pulmonary infection were reviewed. The most common finding was a matched defect in ventilation and perfusion occurring in 40 patients (76%). Regional reverse mismatch occurred in 13 patients (24%) and both appearances were found in one patient (2%). Reverse mismatch was also present in a further seven patients, four of whom had bronchial obstruction. Although occurring less frequently than matched defects, 81% of regional reverse mismatched defects were because of chest infection. The presence of regional reverse mismatch in patients investigated for pulmonary embolism suggests the alternative diagnosis of chest infection.

Adult↗
PubMed1994

Functional imaging of changes in human intrarenal perfusion using quantitative dynamic computed tomography.

RATIONALE AND OBJECTIVES: Quantitative dynamic computed tomography was used with perfusion imaging to characterize intrarenal variations in perfusion in normal and abnormal human kidneys. METHODS: Perfusion images were obtained from 14 normal and four abnormal kidneys, comprising a renal tumor, an infarcted renal allograft, and two kidneys in a patient with cyclosporin toxicity. RESULTS: Images demonstrating quantifiable intrarenal variations in perfusion were consistently obtained. Normal cortical and medullary perfusion were 4.7 mL/min/mL and 1.1 mL/min/mL, respectively, consistent with accepted normal ranges. The changes in the abnormal kidneys corresponded with known pathophysiology. CONCLUSION: Computed tomography perfusion imaging creates quantifiable images of renal perfusion with a spatial resolution currently higher than any other functional imaging technique. It offers the opportunity to characterize renal diseases by their relative effects on cortical and medullary perfusion.

Adult↗
PubMed1994

Bone marrow scintigraphy in small cell carcinoma of the lung.

A comparative study of bone marrow scintigraphy using 99Tcm-nanocolloid, conventional bone scintigraphy and bone marrow biopsy were performed in 35 patients with histologically proven small cell carcinoma of the lung to determine whether bone marrow scintigraphy has a role in the early detection of bone marrow metastases. The sensitivity, specificity and accuracy for detection of metastases were 100, 92 and 94%, respectively, in bone marrow scintigraphy, 91, 88 and 89%, respectively, in bone scintigraphy, and 50, 100 and 86%, respectively in bone marrow biopsy. This study confirmed that bone marrow scintigraphy is a useful technique for the detection of early metastases. Bone marrow scintigraphy is also suggested as the first choice examination in clinical practice for diagnosis of metastases in small cell carcinoma of the lung.

Adult↗
PubMed1994

Can 99Tcm HMPAO leucocyte scintigraphy distinguish between Crohn's disease and ulcerative colitis?

This paper has retrospectively analysed the ability of 99Tcm HMPAO leucocyte scintigraphy to distinguish Crohn's disease from ulcerative colitis. The diagnostic criteria were established by reviewing 99Tcm HMPAO leucocyte scintigrams in 123 patients with histologically proven Crohn's disease (83) or ulcerative colitis (40). Uptake in the right iliac fossa with or without other segments of colon, irregular bowel uptake, small bowel uptake or colonic activity with rectal sparing were all strongly suggestive of Crohn's disease. Left sided colitis was found to indicate ulcerative colitis. Total colitis occurred in both ulcerative colitis and Crohn's disease. The criteria were later tested in an additional 62 patients with excellent results (accuracy 98%). In 63 patients in whom the results of barium radiology were also available, the accuracy of scintigraphy was higher (93% and 83%, respectively). We conclude that 99Tcm HMPAO leucocyte scintigraphy can accurately distinguish between Crohn's disease and ulcerative colitis in a large proportion of cases and appears to be more reliable than conventional radiology.

Barium Sulfate↗
PubMed1994

Technical note: bone SPECT of the wrist.

A technique for single photon emission computed tomography (SPECT) during bone scintigraphy of the wrist is described. The technique has been developed as a means to improve localization of abnormalities observed on 99Tcm-MDP planar bone scintigraphy. A wrist phantom and 15 wrists in 13 symptomatic patients were examined. Good spatial detail was achieved, with the pisiform readily identifiable as a separate bone in six wrists. In seven cases the tomograms permitted better localization of planar image abnormalities and in four cases additional lesions were visible which were missed on planar scintigraphy. This technique can be applied to all patients with suspected carpal injury and allows better anatomical localization and greater sensitivity than planar scintigraphy alone.

Adolescent↗
PubMed1993

Computer-derived regions of interest for the determination of renal parenchymal transit time.

Renal parenchymal transit time measurements are used in the diagnosis of obstructive nephropathy but parenchymal regions are usually drawn by hand with or without the aid of a functional image. This paper describes three computerized methods for derivation of parenchymal regions from a mean time functional image and compares them with the manual method by processing renogram data from 82 normal, 19 obstructed and 11 dilated nonobstructed kidneys using all four techniques. Receiver-operator characteristic analysis demonstrated the computer methods to be superior to manually drawn regions. The optimum computer method had a sensitivity of 95% and specificity 95% for distinguishing obstructed kidneys from dilated nonobstructed kidneys. The computer method could be readily incorporated into routine renogram analysis programs.

Electronic Data Processing↗
PubMed1993

Multidose use of exametazine for leukocyte labelling: a new approach using tin enhancement.

Reconstituted exametazime is inherently unstable due to the rapid oxidation of the small amount (7.6 micrograms) of stannous chloride present in the kit. A novel approach has been used to improve the shelf-life of reconstituted exametazime based on the premise that tin lost through oxidation should be replaced by further amounts of tin. Freshly prepared stannous solution, 0.1 ml (0.66 microgram Sn2+), was mixed with 0.3 ml (25 micrograms) exametazime solution followed by 400-500 MBq pertechnetate. Mixed leukocytes from 50 ml of patients' blood were labelled with 99Tcm-exametazime which had been prepared by the tin enhancement. One hundred and fourteen patients were investigated. The median labelling efficiency was 72%, range 30-96%. The exametazime had been reconstituted up to 5 months previously. Because of the small volumes of the exametazime solution used, up to 15 doses for leukocyte labelling could be prepared from one vial.

Butanones↗