Browsing by Author "Mann, Michael D"

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    Aspects of paediatric gastro oesophageal scintigraphy
    (1988) Wynchank, Sinclair; Mann, Michael D
    This work is concerned with the application of scintigraphy in studies of foregut motility in paediatric patients; notably oesophageal transit during swallowing, gastro oesophageal reflux (GOR) and stomach emptying as measured by the gastric contents 30 and 120 minutes after deglutition of liquid. Relevant anatomy, physiology, pathophysiology and non-radioisotopic methods of gastro oesophageal examination are outlined. The extremely important question of dose deposited by ionising radiation in paediatric patients is also considered. Because currently available estimations of absorbed dose after swallowing non- absorbable radionuclides are unsatisfactory and often contradictory, a new model was derived. It is based on more physiological principles than previous models, with a continuously varying exponential passage between four compartments in the gastrointestinal tract. From a review of previous work and our experience, a standard method of examination was developed. There is emphasis on normal physiological manoeuvres. The broad extent of useful information available in the study stems from the positions in which the patient is investigated, the quantity of labelled fluid swallowed, its physiological nature and observations of oesophageal transit, GOR, gastric emptying and pulmonary aspiration after two hours. The wide range of paediatric problems amenable to investigation by this means is described, including those of a life-threatening nature. Also, the importance of using this examination to determine the likelihood of successful surgical intervention in the gastro oesophageal region is explained. By using the observations made during swallows in neonates, the closure of the lower oesophageal sphincter (LOS) was observed during a short series of rapid deglutitions. This extends previous knowledge of the function of the neonatal LOS. These findings were very clearly demonstrated by the condensed image technique. A comparison between the abilities of radiology and scintigraphy to detect GOR in paediatric patients, with and without oesophagitis, gives unequivocal results in favour of scintigraphy. Two independent clear correlations between oesophageal transit time and the severity of GOR and age are demonstrated by variance and correlation analysis. The mean duration of GOR, maximum height of a GOR, gastric contents 30 and 120 min after deglutition, the effect of the nature of liquid swallowed and age are also examined and their relations are described. The application of the method to assess drug response is illustrated by the paediatric use of cisapride, an experimental drug which increases acetylcholinesterase release. The deductions from this work include values of the radiation dose deposited in paediatric patients of various ages, after swallowing non- absorbed Tc-99m compounds. Other contributions are a scintigraphic means to allow recognition of the importance of oesophageal dysmotility in paediatrics, especially in the absence of GOR and its relevance to the efficacy of surgery in cases of apparent GOR. Also, this gastro oesophageal scintigraphic study provided information on the paediatric use of cisapride, the relevance of GOR to repeated respiratory problems and the recognition of a new paediatric syndrome analogous to the diffuse oesophageal spasm syndrome of adulthood. It has been demonstrated that a routine, uncomplicated, paediatric scintigraphic examination, useful for investigating a wide range of problems in both a first and third world setting is possible for a nuclear medicine practitioner with normally available radiopharmaceuticals, equipment and radiographical expertise.
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    Assessment of the impact of the application single photon emission computerized tomography and SPECT-CT on lesion catergorization
    (2015) Yunusa, Garba Haruna; Brink, Anita; Mann, Michael D
    Objectives: To assess initial experience with the use of a new SPECT-CT in the evaluation of lesions. Methods: The folder number, radiopharmaceutical used and type of scan of patients examined with a new Siemens T6 SPECT-CT between 2 April and 31 December 2013 were retrieved. The number of 99m Tc -MDP bone scans was sufficient for a detailed analysis. The scans were re-processed and reported by the observer before he was given any clinical information. Whole body planar, whole body planar plus SPECT and whole body planar plus SPECT-CT images were assessed successively in three separate sessions at least two weeks apart. At each session, the certainties of detection, localisation, and categorisation of each lesion were recorded. Results: A total of 539 lesions were seen on the whole body, SPECT and CT images in 133 patients. The whole body images showed no lesions in three patients and 378 lesions in 130 patients, 117(31%) lesions in areas not covered by the SPECT. SPECT detected 122 additional lesions in 79 patients. Thirty-nine (12.2%) lesions were seen only on CT in 32 (24.1%) patients. F or the 261 lesions seen on the planar images in the SPECT FOV, lesion detection was definite in 233 (89.3%), localisation definite in 151(57.9%) and categorisation definite in 123 (47.1%) lesions. On the SPECT, definite lesion detection, localisation and categorisation were recorded respectively for 259 (99.2%), 228 (87.4%) and 176 (67.4%) of the 261 lesions. Lesion detection, localisation and categorisation certainties were definite for 100%, 99.1% and 94.7% of the SPECT-CT lesions respectively. Conclusion: Whole body planar scintigraphy is essential in lesion detection. SPECT markedly improves lesion detection and localisation and CT enhances lesion categorisation.
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    Colonic transit in subjects with spinal cord injuries
    (2001) Freedman, Patricia Noel; Mann, Michael D
    The rehabilitation of patients with spinal cord injuries (SCI) is long and difficult. Not only do they lose mobility but they also have changes in bowel continence caused by loss of voluntary motor and sensory function and damage to the visceral nerve supply. The maintenance and management of bowel function causes major morbidity for subjects with SCI. The effect of SCI on colonic function is poorly understood and little studied. Aim: This study sought to establish a method of studying regional colonic transit and to investigate whether the level of SCI influences colonic transit. Patients and Methods Sixteen subjects (8 paraplegics and 8 tetraplegics) with spinal cord injury, at least one year previously were recruited. The tetraplegics group had spinal cord injuries above T1 and the paraplegic group had injuries below T1 . They were given a pancake labelled with 10-18 Mbq of ln-111 Amberlite resin to eat. Anterior and posterior images were acquired for 400 seconds each, using a 40 cm field of view gamma camera, once on the first day and then 3 times a day for the next 4 days. The subjects were asked to report every time they had a bowel evacuation. No laxatives or enemas were permitted during the study. Subjects were permitted to eat and drink normally after the first images (3 hours) were acquired. Seven regions of interest (ROI) outlining, 1) ascending colon, 2) hepatic flexure, 3) transverse colon, 4) splenic flexure, 5) descending colon, 6) rectosigmoid and 7) total abdominal activity, were drawn on each set of anterior and posterior images. The counts were decay corrected. The decay corrected counts were used to calculate the geometric mean (GM), for each region, at each time point. The GM was used to calculate the percentage of the total abdominal activity in each region, at each time point. Colonic transit was assessed in 4 ways. Firstly, 3 independent Nuclear Medicine Physicians visually assessed transit on hard copies of the images and classified subjects into 5 categories of colonic transit (rapid transit, intermediate transit, generalised delay, right-sided delay or left-sided delay). Secondly, parametric images were constructed from the percentage activity in each region at each time point. Thirdly, the arrival and clearance times of the activity in the right and left colon were plotted as time-activity curves. Finally, the geometric centre of the distribution of the activity was calculated and plotted on a graph versus time. The parametric images, time activity curves of the right and left sides of the colon and the geometric centre for each subject were classified into the same categories as the visual assessment. All statistics were assumed to be non-parametric. Results: The results of the four methods of assessing colonic transit were compared and the majority categorisation was accepted as the final diagnosis. The best agreement occurred between the parametric images and the arrival and clearance times of the activity in the right and left colons. No single method was consistently correct. Amongst the paraplegic subjects, two had generalised delay, four had rightsided delay, and two left-sided delay. In the tetraplegic subjects, two had intermediate transit, 1 generalised delay, and 5 left-sided delay. Conclusion A combination of at least two methods of determining colonic is necessary. The level of spinal cord injury effects colonic transit. Injuries below T7 /T8 result in right-sided delay. Injuries above this most commonly result in left-sided delay. Occasionally injuries above T7/8 can result in intermediate transit or generalised delay. Paraplegics are more likely to have right-sided delay (p =0.04), whereas tetraplegics are more likely to have left-sided delay.
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    The development of a neonatal vital signs database
    (1992) Berelowitz, Jonathan; Poluta, Mladen; Woods, David R; Van der Elst, Clive; Mann, Michael D
    Modern intelligent monitoring systems use digital computer technology to analyze and evaluate physiological vital signs. This analytical and evaluative process is performed by algorithms developed for this purpose. The degree of 'intelligence' of the monitoring system is dependent on the 'sensitivity' and 'specificity' of these algorithms. In order to develop robust and clinically valid algorithms, a database of representative waveforms is required. The aim of this thesis was to create a neonatal vital signs database to be used for this purpose, by means of a computer-based central station. The computer was interfaced to a number of neonatal monitors (Neonatal ICU, Groote Schuur Hospital). The monitors were interrogated to obtain patient condition, ECG waveforms and respiration waveforms using the impedance technique. When possible, percentage oxygen saturation was also captured. The database contains 509 documented clinical records obtained from 35 patients and 20 records containing examples of technical alarm conditions and high frequency noise. Additional patient record data is included. Clinical events recorded include apnoea, bradycardia, periodic breathing tachycardia, tachypnoea and normal traces. These events were recorded against a variety of signal quality conditions that have been characterized in Appendix C. A prototype rate detection algorithm was checked using samples from the database.
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    The diagnostic accuracy to Technetium 99m labelled erythrocyte scintigraphy in the investigation of hepatic mass lesions : special reference to hepatic cavernous haemangioma and hepatocellular carcinoma
    (1995) Lourens, Steven; Mann, Michael D
    The distinction between cavernous haemangiomas of the liver (which are the second most common hepatic mass lesions) from malignant lesions, is often difficult. An incorrect diagnosis of cavernous haemangioma, in a patient with malignancy, may adversely influence the outcome of subsequent treatment in these patients, due to delay in therapy. Although previous studies have suggested that ⁹⁹ᵐTc erythrocyte blood pool scintigraphy is both highly sensitive and specific for haemangiomas, a basic flaw in all previous studies has been the small number of control patients studied. Bayesian analysis clearly shows that specificity for a test is dependant on the pre-test probability of the lesion being present. Thus all the studies done to date, may reflect an inappropriately high specificity for ⁹⁹ᵐTc scintigraphy, in diagnosing cavernous haemangiomas, because they have mainly studied patients with haemangiomas and relatively few patients with other lesions. This study was thus undertaken to clarify the true accuracy of this technique, in distinguishing haemangiomas from other hepatic mass lesions, by studying a large number of patients with haemangiomas and other hepatic mass lesions.
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    The differentiation of extrahepatic biliary atresia from the neonatal hepatitis syndrome
    (1989) Daubenton, John David; Mann, Michael D
    The differentiation, in an infant with cholestasis, between extrahepatic biliary atresia (EHBA) and the neonatal hepatitis syndrome (NHS) is important in that laparotomy is always indicated in EHBA but is undesirable in NHS. This differentiation is particularly difficult in those infants with complete cholestasis. Hepatobiliary scintigraphy is a commonly used investigation in infants with obstructive jaundice. The scintigraphic demonstration of excretion into the gut excludes extrahepatic obstruction, however, absence of excretion may be due to EHBA, severe cholestasis with patent extrahepatic bile ducts or poor uptake of the agent, and is therefore not diagnostic. This study has examined the quantitative measurement of the hepatic uptake of p-butyl IDA and Sn colloid, and an estimation of liver shape, in a group of patients with complete cholestasis in whom conventional scan interpretation, based on excretion into the-gut, would not be useful. The scans were recorded as dynamic studies and the resultant time-activity curves were subjected to curve fitting to calculate a rate constant for uptake of radiopharmaceutical. Liver shape was determined from the anterior static image of the colloid scan. The results show a significant difference between the EHBA and the NHS patients in the rate of uptake of p-butyl IDA, in the ratio of the rate of uptake of p-butyl IDA/the rate of uptake of colloid and in the measurements used to express liver shape. Using this method of scan interpretation, a diagnostic accuracy of 85% was achieved in this study of patients who clinically, and on scan, had no evidence of bile flow. Hepatic scintigraphy is therefore a useful investigation in the diagnostic work-up of infants presenting with obstructive jaundice even when bile flow is completely absent.
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    Radioactive lead studies in the human
    (1980) Blake, Keith Charles Hughes; Mann, Michael D
    The differing susceptibility of individuals to the toxic effects of chronic lead exposure has never been fully understood. As the major intake of lead in the human is from food and beverages, any variation between individuals of the quantity of lead absorbed from the gut, and of the distribution and excretion of this lead, may account for the differences in individual susceptibility. The food and beverages themselves may have an influence, and to investigate their effects on absorption, distribution and excretion of lead, experiments were performed on normal subjects using a short-lived radionuclide of lead, ²⁰³Pb, and instruments generally available in Nuclear Medicine. Lead absorption between different individuals showed a wide variation when ²⁰³Pb was taken as a single dose between meals. The effect of fasting was to increase absorption and reduce the variation. This suggested that food with the lead in the gut was mainly responsible for the variation in lead absorption between individuals. This was confirmed when ²⁰³Pb was mixed into a control meal and eaten by fasted subjects. Lead absorption was again low and variable. In contrast, ²⁰³Pb taken in distilled water was avidly absorbed with little variation between subjects. The absorption of lead in water could be appreciably more than lead in food amongst the general population. Minerals were found to be mainly responsible for affecting absorption when one subject ingested ²⁰³Pb in control meals from which one dietary constituent at a time was omitted. The effect of minerals in reducing absorption of lead was greatest when they were ingested in distilled water. Lead in water with a low mineral content, such as 'soft' water, could be a hazard to population groups living in 'soft' water areas. There were also indications from these experiments that dietary constituents may affect the distribution and excretion of lead. Calcium and phosphorous were found to reduce the absorption of ²⁰³Pb to approximately the same level as that produced by the total minerals. Calcium reduced absorption more than phosphorous when these minerals were ingested separately with ²⁰³Pb. Paired kinetic experiments showed that calcium and phosphorous ingested at the same time as ²⁰³Pb affected its distribution in the body but not its rate of excretion. Using the data from the kinetic experiments, a compartmental model was developed which adequately described the kinetics of orally ingested ²⁰³Pb. The model suggested that calcium is mainly responsible for reducing absorption of lead from the gut, but that the effect of phosphorous is to increase soft tissue levels of lead at the expense of red cell lead. As susceptibility is related to soft tissue levels of lead, this suggests that the 'protective' effect of calcium in the gut is reduced. This could not be confirmed, however, as the kinetic data were insufficient for the model to distinguish the tissues particularly vulnerable to lead toxicity in the soft tissue compartment. It was concluded that the calcium and phosphorous in the diet could influence susceptibility to lead toxicity through changes in the absorption of food and water lead and in the distribution of lead in the body. The results suggest that the prophylactic effect of calcium on lead absorption should be recognised and applied in this time of increased environmental levels of lead.
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    Relationship between ¹²³l-metaiodobenzylguanidine (¹²³l-MIBG) imaging findings and outcome in patients with neuroblastoma at the Red Cross War Memorial Children's Hospital
    (2017) Amoako, Yaw Ampem; Brink, Anita; Mann, Michael D
    Background: In neuroblastoma, the presence of distant metastases is associated with a poor prognosis. Aim: To assess the relationship between the findings on ¹²³I-MIBG scan and outcome in patients with neuroblastoma at the Red Cross War Memorial Children's Hospital (RCWMCH). Methods: A single observer reviewed the ¹²³I-MIBG scans and clinical data of patients who had a histologically confirmed diagnosis of neuroblastoma and a baseline ¹²³I-MIBG scan and at least one follow up scan after chemotherapy cycles 4 or 7 between January 2001 and May 2015. Follow up extended to June 2016. Disease burden was assessed using the Curie scoring (CS) method. Results: Thirty four stage 4 patients were included in the analysis. Twenty nine (85%) were older than 12 months, with a median age at diagnosis of 32.5 months (range 6 - 93 months). 62% of primary tumours were located in the adrenal gland and half were NMYC amplified. Twenty (59%) patients died, 90% of deaths occurring in patients older than 12 months. No deaths were recorded in the 13 months after recruitment ended. The baseline CS did not predict outcome (alive or dead) or duration of survival. Patients with CS >2 (n = 5) on the cycle 4 scan had a median survival of 19.5 months compared with 29 months for those with a score ≤ 2 (n = 17, p = 0.88). Patients with a CS > 2 on the cycle 7 scan (n = 7) had a median survival of 28 months compared with 35 months for those with CS ≤ 2 (n = 14, p = 0.93). There was no relationship between the magnitude of the decrease in CS between the baseline and post cycle 4 or 7 scans and outcome. Conclusion: In these 34 high risk patients, the baseline CS and CS at cycle 4 or cycle 7 were not significantly indicative of survival. This is similar to other studies that did not find the pre-treatment score or the post treatment MIBG scan to be a predictor of outcome.
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    The role of Technetium-99m Sestamibi scintimammography to evaluate palpable breast lesions : a comparison with mammography and histological results
    (1999) Nizami, Mohammad Athar Farooq; Mann, Michael D; Dent, David Marshall; Adams, Bruce K
    This study was conducted with the support of the Combined Breast Clinic at our institution which consists of the Departments of Surgery, Radiology and Radiation Oncology. The work was done in three parts. The literature showed somewhat lengthy imaging procedure for scintimammography which were not whole suitable to the setting of the Combined Breast Clinic. Initially a Pilot Study was conducted to determine the practicality of the imaging procedure. The results of this study were promising but the imaging procedure was time consuming. Certain modifications were subsequently done in the imaging method of the Formal Study to accommodate more number of patients into the study without jeopardizing the quality of the images. This study, however, had a shortcoming in that the way this study was structured one could not demonstrate lesion by lesion analysis of each breast lesion detected on clinical examination, mammography and scintimammography with their respective biopsy results. Our Formal Study and the literature suggested that scintimammography is of value in patients with indeterminate mammograms due to its high negative predictive value. Therefore, a separate Additional Study, with the same scintigraphic method, was conducted on patients with clinical breast lumps with indeterminate mammographic lesions. Special emphasis was placed on lesion by lesion comparison of each breast lesion detected by clinical examination or scintimammography or both with the biopsy results of that particular lesion.
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    Small intestinal bacterial overgrowth in acute and persistent infantile diarrhoea
    (1992) Frischman, William John; Mann, Michael D
    INTRODUCTION: Small intestinal bacterial overgrowth refers to the proliferation of abnormal numbers and types of microorganisms in the lumen of the proximal bowel. Bacterial overgrowth has been implicated as a possible factor in prolonging some episodes of infantile gastroenteritis. This thesis examines 2 different aspects of the duodenal flora of infants with gastroenteritis, and has therefore been divided into 2 separate studies. CARBOHYDRATE STUDY: Objective: To test the hypothesis that during a diarrhoeal episode the presence of malabsorbed carbohydrate in the duodenal lumen acts as a factor promoting bacterial proliferation. Patients and methods: Infants admitted to the rehydration ward with acute gastroenteritis were selected for study if they fulfilled various criteria in terms of age, nutritional status, previous diarrhoeal episodes and antibiotic administration. They were admitted to the research ward. Weights were measured and if they had severe diarrhoea (≥ 30g/kg) were included in the study. Twenty patients were entered into the study. On admission into the trial the first duodenal intubation was done to measure the duodenal flora quantitatively and qualitatively. Thereafter the patients were assigned on an alternate basis to one of 2 groups. One group (carbohydrate-containing group) received a soy-based infant formula containing carbohydrates (Isomil, Ross). The other group (carbohydrate-free group) received an identical milk but from which all carbohydrate had been omitted (Ross CHO-free). To these infants carbohydrate was given intravenously. Stool output was measured daily. After 3 days of the respective diets the duodenal flora was re-examined. Results: Longitudinal analysis of the duodenal flora of the carbohydrate-containing group showed a small decrease in the number of bacterial isolates and in their magnitude. The duodenal flora of the carbohydrate-free group was virtually unchanged. Comparing the duodenal bacteriology of the groups the only significant difference was that the number of isolates and the magnitude of Haemophilus was greater in the carbohydrate-free group- (p < 0.05). The diarrhoea resolved in 5 patients: 2 in the carbohydrate-containing and 3 in the carbohydrate-free group. Conclusions: The lack of difference in the response of the duodenal flora between the two groups studied suggests that the presence of carbohydrates in the lumen is not important in encouraging the growth of bacteria in that site. The possible causes for an increase in Haemophilus numbers in the carbohydrate-free group are discussed. BOWEL COCKTAIL STUDY: Objective: Small intestinal bacterial overgrowth has been proposed as a cause of progression of acute diarrhoeal episodes to persistence. The "bowel cocktail", a combination of oral gentamicin and cholestyramine, has been shown to be effective in terminating episodes of persistent diarrhoea. It has been postulated to work by eradicating small intestinal bacterial overgrowth, but its mode of action is not known. The objective of this study was to examine the changes in the duodenal flora associated with administration of the bowel cocktail in order to elucidate its possible mechanism or mechanisms of action. Patients and methods: The study group comprised 15 patients. Fourteen were infants from the carbohydrate study who had ongoing diarrhoea. The remaining infant (the "late entry") was selected from the rehydration ward. Severe diarrhoea, as defined by a stool output equal to or greater than 30g/kg/day, was a pre-requisite for entry into the study. The investigation involved 2 duodenal intubations for microbiological analysis of the duodenal fluid. After the first intubation (which was the second intubation for the 14 infants who had been in the carbohydrate study) the bowel cocktail was administered. This comprised a 3-day course of oral gentamicin and 5 days of oral cholestyramine. Forty-eight hours after the start of therapy the duodenal bacteriology was repeated. The patient management was the same as during the carbohydrate study and the feeding regimen of the infants was not altered. The study ended immediately after completion of the bowel cocktail course. Results: Administration of the bowel cocktail was associated with a decreased stool output in all patients. Bacteriological analysis of the duodenal flora after this treatment showed a statistically significant decrease in the total microbial count, the aerobic microbial fraction and the Enterobacteriaceal fraction. On analysis of the bacterial genera a significant decrease was noted in Neisseria, Haemophilus, and aerobic lactobacilli. Analysis of individual patients' duodenal fluid bacteriology in conjunction with the stool bacteriology results before administration of the bowel cocktail often provided an explanation as to the possible aetiology of the diarrhoea and its resolution by therapy. Conclusions: Small intestinal bacterial overgrowth, in the accepted sense of a luxuriant flora teeming with faecal organisms, did not appear to be a feature of the patients in this study. The total bacterial count was only slightly above the accepted upper limit of normal. Although the decrease in the number of Enterobacteriaceae could possibly be interpreted in the context of bacterial overgrowth, a study of the individual patients' duodenal flora shows that these microorganisms were more likely to be acting as specific enteric pathogens. It is concluded that small intestinal bacterial overgrowth, as currently defined, is not an important cause of persistent diarrhoea. The efficacy of the bowel cocktail is more likely to reside in its ability to eradicate specific enteric pathogens. The author ends by questioning the validity of the whole concept of small intestinal bacterial overgrowth.
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    The use of scintigraphy to study gastric emptying, motility and small intestinal transit in patients who have ingested a selection of common poisons
    (1995) Adams, Bruce Keith; Mann, Michael D
    Poisoning is common and carries considerable morbidity and mortality. Two to three patients are admitted to the Emergency Unit at Groote Schuur Hospital every day with drug overdose. As absorption occurs in the small intestine the rates at which ingested poisons pass into and through the small bowel are important factors in determining the amount of poison potentially available for absorption. Although the effects of pharmacological doses of many drugs on gastric emptying and motility are known, information on the effects of higher doses is limited. I investigated patients who took overdoses of certain commonly used drugs to determine their effects on gastric emptying and motility and small intestinal transit. The study was divided into two parts. One hundred and four patients were studied in Part 1. These patients took overdoses of tricyclic antidepressants (n = 31), carbamazepine (n = 15), phenytoin (n = 12), paracetamol (n = 29) and opioid-paracetamol mixtures (n = 17). They received standard hospital management of which sorbitol was not a part. Part 2 consisted of sixty-one patients who had sorbitol added to their treatment. These patients had taken overdoses of the tricyclic antidepressants (n = 15), carbamazepine (n = 7), phenytoin (n = 8), paracetamol (n = 13) and opioid-paracetamol mixtures (n = 18). The effects of sorbitol on gastric emptying and small intestinal transit were evaluated. A third study-the paracetamol control test was done on 5 healthy volunteers. Each subject was studied twice; the first time after taking 1 G of paracetamol and the second time after no drug ingestion.