SUNScholar - Browsing by Author "Warwick, James M."

Browsing by Author "Warwick, James M."

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A comparison of the effects of citalopram and moclobemide on resting brain perfusion in social anxiety disorder.
(2006) Warwick, James M.; Carey P.; Van der Linden G.; Prinsloo C.; Niehaus D.; Seedat S.; Dupont P.; Stein D.J.
INTRODUCTION: The serotonin specific reuptake inhibitor (SSRI) citalopram and the reversible mono-amine oxidase-A inhibitor (RIMA) moclobemide have both been used successfully for the treatment of social anxiety disorder (SAD). In this study we investigate the effects of these compounds on resting brain function using single photon emission computed tomography (SPECT). METHODS: Subjects meeting DSM-IV criteria for SAD underwent regional cerebral blood flow (rCBF) SPECT using Tc-HMPAO at baseline and after 8 weeks of treatment with either citalopram or moclobemide. Using statistical parametric mapping brain SPECT studies were analysed to determine the effects of treatment on rCBF, to compare the effects of citalopram and moclobemide, and to detect correlations between changes in rCBF and clinical response. RESULTS: Subjects received citalopram (n=17) or moclobemide (n=14) as therapy. Subjects in both treatment groups demonstrated a significant improvement of SAD symptoms as measured by the Liebowitz Social Anxiety Scale total score. All subjects demonstrated a decrease in rCBF in the insulae post therapy. Subjects receiving citalopram had decreased superior cingulate rCBF after therapy compared to those receiving moclobemide. CONCLUSION: Both SSRI's and RIMA's decreased rCBF in the insulae during treatment of SAD; an effect that may be consistent with the role of these regions in processing internal somatic cues evoked by emotional stimuli. Citalopram had a greater effect on superior cingulate perfusion, an effect that is consistent with evidence of high levels of 5-HT transporters in this region.
Alcohol-induced psychotic disorder: brain perfusion and psychopathology--before and after anti-psychotic treatment.
(2012) Jordaan G.P.; Warwick, James M.; Nel D.G.; Hewlett R.; Emsley R.
Alcohol-induced psychotic disorder (AIPD) also known as alcohol hallucinosis is a rare complication of alcohol abuse. The pathogenesis and treatment of AIPD are still unclear. Few prospective treatment studies are available but case reports generally suggest that anti-psychotic treatment is effective. Brain imaging changes in relation to treatment response have also not been studied except for case reports. The aim of this study was to investigate the effect of anti-psychotic treatment on psychopathology and regional cerebral blood flow (rCBF) in patients with AIPD before and after 6 weeks of treatment. Nineteen patients with AIPD were assessed by the Positive and Negative Syndrome Scale (PANSS) and single photon emission computed tomography (SPECT) before and after 6-weeks of open-label treatment with a fixed dose of haloperidol (5 mg/day). Highly significant improvements were noted on the positive, general and total scores of the PANSS. Post-treatment increased rCBF to the left caudate and left frontal lobe was noted. Changes in frontal, temporal, parietal, occipital, thalamic and cerebellar rCBF showed significant negative correlations with the degree of symptom improvement, suggesting dysfunction of these areas in AIPD. Psychopathological and rCBF findings suggest reversible generalised cerebral dysfunction in AIPD.
Appropriate indications for positron emission tomography/computed tomography : College of Nuclear Physicians of the Colleges of Medicine of South Africa
(Health & Medical Publishing Group, 2016) Sathekge, Mike; Warwick, James M.; Doruyter, Alex; Vorster, Mariza
Individualised patient treatment approaches demand precise determination of initial disease extent combined with early, accurate assessment of response to treatment, which is made possible by positron emission tomography/computed tomography (PET/CT). PET is a non-invasive tool that provides tomographic images and quantitative parameters of perfusion, cell viability, and proliferation and/or metabolic activity of tissues. Fusion of the functional information with the morphological detail provided by CT as PET/CT can provide clinicians with a sensitive and accurate one-step whole-body diagnostic and prognostic tool, which directs and changes patient management. Three large-scale national studies published by the National Oncologic PET Registry in the USA have shown that imaging with PET changes the intended patient management strategy in 36.5% to 49% of cases, with consistent results across all cancer types. The proven clinical effectiveness and growing importance of PET/CT have prompted the College of Nuclear Physicians of South Africa, in collaboration with university hospitals, to develop a list of recommendations on the appropriate use of fluorine-18-fluorodeoxyglucose (18F-FDG) and non-18F-FDG PET/CT in oncology, cardiology, neurology and infection/inflammation. It is expected that other clinical situations will be added to these recommendations, provided that they are based upon solid clinical evidence. These recommendations are intended to offer advice regarding contemporary applications of PET/CT, as well as indicating novel developments and potential future indications. The CNP believes that these recommendations will serve an important and relevant role in advising referring physicians on the appropriate use of 18F-FDG and non-18F-FDG PET/CT. More promising clinical applications will be possible in the future, as newer PET tracers become more readily available.
Brain SPECT in Social Anxiety Disorder: A Comparison of Pharmacotherapeutics
(2005) Warwick, James M.; Carey P; Van Der Linden GJH; Prinsloo C; Dupont P; Stein DJ
A case for the provision of positron emission tomography (PET) in South African public hospitals
(Health and Medical Publishing Group, 2006-07) Sathekge, M. M.; Warwick, James M.; Vangu, M. D. T.; Ellmann, A.; Mann, M.
Nuclear medicine is expanding into new areas of clinical practice, of which positron emission tomography (PET) is an example. As in new treatments with labelled monoclonal antibodies, especially for lymphoma, the wide introduction of PET into health care in South Africa presents benefits and challenges to patients, doctors, and funders. PET is an imaging modality that has been available in specialised centres in the developed world since the 1970s. It was initially used as a research tool to image organ function in vivo. The development of the radiopharmaceutical F-18- fluorodeoxyglucose (FDG), a glucose analogue taken up avidly by the majority of tumours, has resulted in PET now being used routinely in the management of many cancer patients in centres with access to it. There has been rapid growth of PET in the developed world and it has also been introduced into developing countries, including Egypt. We welcome government initiatives to establish PET imaging in South Africa, as evidenced by the provision of cyclotrons in Gauteng and Cape Town.
Changes in regional brain volumes in social anxiety disorder following 12 weeks of treatment with escitalopram
(2010) Cassimjee N.; Fouche J.-P.; Burnett M.; Lochner C.; Warwick, James M.; Dupont P.; Stein D.J.; Cloete K.J.; Carey P.D.
It has been suggested that antidepressants, including the selective serotonin reuptake inhibitors have neurotrophic effects. Nevertheless, the impact of treatment with a selective serotonin re-uptake inhibitor on regional brain volumes in social anxiety disorder has not been studied. 11 subjects with social anxiety disorder completed magnetic resonance imaging both before and after 12-weeks of treatment with 20 mg/day escitalopram. No increases in structural grey matter were found, but there were decreases in bilateral superior temporal cortex, vermis and the left cerebellum volumes following 12 weeks of treatment with escitalopram. These preliminary findings require replication to determine their reliability, and extension to determine whether or not they are disorder specific. © 2010 Springer Science+Business Media, LLC..
The College of Nuclear Physicians of South Africa practice guidelines on peptide receptor radionuclide therapy in neuroendocrine tumours
(Health and Medical Publishing Group, 2018) Lawal, I.; Louw, L.; Warwick, James M.; Nyakale, N.; Steyn, R.; Lengana, T.; Ellmann, A.; Kotze, T; Vangu, M.; Vorster, M.; Sathekge, M.
Background: Peptide receptor radionuclide therapy (PRRT) for metastatic or inoperable neuroendocrine tumours (NETs) is a systemic therapy which targets somatostatin receptors overexpressed by differentiated NETs for endoradiotherapy. This guideline has been compiled by the College of Nuclear Physicians of the Colleges of Medicine of South Africa, with endorsement by the South African Society of Nuclear Medicine and the Association of Nuclear Physicians to guide Nuclear Medicine Physicians in its application during the management of these patients. Recommendations: Patients with well- to moderately-differentiated NETs should be comprehensively worked-up to determine their suitability for PRRT. Treatment should be administered by a Nuclear Medicine Physician in a licensed, appropriately equipped and fully staffed facility. Patient monitoring is mandatory during and after each therapy cycle to identify and treat therapy-related adverse events. Patients should also be followed-up after completion of therapy cycles for monitoring of long-term toxicities and response assessment. Conclusion: PRRT is a safe and effective therapy option in patients with differentiated NETs. Its use in appropriate patients is associated with a survival benefit.
Disrupted functional connectivity in social anxiety disorder: a resting-state fMRI study
(2011-05-25) Ding J.; Chen H.; Qiu C.; Liao W.; Warwick, James M.; Duan X.; Zhang W.; Gong Q.
Dysfunction of the corticolimbic circuitry has been highlighted in social anxiety disorder (SAD) during social stimuli. However, few studies have investigated functional connectivity in SAD during the resting state, which may improve our understanding of SAD pathophysiology. The aim of this study was to investigate whether whole-brain functional connectivity might be aberrant in SAD patients, and if so, whether these changes are related to the measured clinical severity. Seventeen SAD patients and 19 healthy controls participated in resting-state functional magnetic resonance imaging. The brain was first divided into 90 paired brain regions and functional connectivity was then estimated by temporal correlation between each of these regions. Furthermore, connections that were significantly disrupted in SAD patients were correlated with clinical severity measured using the Liebowitz Social Anxiety Scale. Compared with healthy controls, SAD patients showed decreased positive connections within the frontal lobe and decreased negative connections between the frontal and occipital lobes. In particular, the weaker negative connections between the frontal lobe, which mainly involved the right median prefrontal cortex, and the occipital lobe had a significant positive correlation with the severity of SAD symptoms. The results support the hypothesis that some abnormalities of functional connectivity exist in SAD patients, which relate to the frontal cortex and occipital cortex. In addition, decreased functional connectivity between the frontal and occipital lobes and within the frontal lobe might be related to abnormal information processing and reflect disturbed neural organization resulting in defective social cognition, which could represent an early imaging biomarker for SAD. © 2011 Elsevier Inc. All rights reserved.
Dopamine transporter binding in social anxiety disorder: The effect of treatment with escitalopram
(2012) Warwick, James M.; Carey P.D.; Cassimjee N.; Lochner C.; Hemmings, Sian M. J.; Moolman-Smook H.; Beetge E.; Dupont P.; Stein D.J.
Social anxiety disorder (SAD) is characterised by fear of social or performance situations where the individual is exposed to unfamiliar people or to possible scrutiny by others. The literature on dopamine ligands and dopamine genotypes in SAD is however inconsistent. In this study we measured the effects of SSRI pharmacotherapy on dopamine transporter (DAT) binding in patients with SAD, also addressing variability in DAT genotype. Adult subjects meeting DSM-IV criteria for generalised SAD were studied before and after 12 weeks of pharmacotherapy with the selective serotonin reuptake inhibitor (SSRI) escitalopram. DAT single photon emission computed tomography (SPECT) using 123I-FP-CIT was performed at baseline, and repeated at 12 weeks. Striatal DAT binding was analysed for changes following therapy, and for correlations with clinical efficacy, in the whole group as well as for a subgroup with the A10/A10 DAT genotype. The study included 14 subjects (9 male, 5 female) with a mean (SD) age of 41 (±13) years. The subjects' Liebowitz Social Anxiety Scale (LSAS) score was significantly decreased following pharmacotherapy. In the combined group the left caudate and left putamen showed clusters of increased DAT binding after therapy. The left caudate changes were also observed in the subgroup of 9 A10/A10 homozygotes. However no correlation was found between improved symptoms and DAT binding. The changes found in DAT binding in the caudate and putamen may be due to serotonergic activation of dopamine function by SSRI therapy. This is consistent with previous work indicating decreased DAT binding in SAD, and increased DAT binding after SSRI administration. © Springer Science+Business Media, LLC 2012.
Hybrid imaging using low-dose, localizing computed tomography enhances lesion localization in renal hyperparathyroidism
(Lippincott, Williams & Wilkins, 2014-03) Doruyter, Alexander G.; Hartley, Tharbit; Ameyo, Jonathan W.; Davids, M. R.; Warwick, James M.
Background Preoperative localization of parathyroid lesions is potentially beneficial in renal patients with hyperparathyroidism. The aim of this study was to determine the localizing value of hybrid single-photon emission computed tomography combined with low-dose x-ray computed tomography (SPECT/LDCT) compared with SPECT alone and whether the LDCT improved reader confidence. Patients and methods A retrospective study examined parathyroid scintigraphy results of patients previously referred with a diagnosis of renal hyperparathyroidism. All patients underwent planar scintigraphy using technetium- 99m (99mTc)-pertechnetate, which was immediately followed with 99mTc-sestamibi and SPECT/LDCT ∼ 60 min after sestamibi injection and a delayed static image to assess differential washout. Planar subtraction images were generated. Two nuclear physicians, assisted by a radiologist, reported on planar+SPECT images followed by planar+SPECT/LDCT images. Results Thirty-seven patients (males: 21; females: 16) were included (mean age 39 years, range: 23.9–55.5). Mean creatinine level was 878 μmol/l (109–1839), mean corrected calcium level was 2.42 mmol/l (1.77–3.64), and median parathyroid hormone level was 156.2 pmol/l (2.4 to >201). Twenty-three patients had positive planar and SPECT
Imaging of brain function using SPECT
(2004) Warwick, James M.
Single photon emission computed tomography (SPECT) is a technique widely used in nuclear medicine for the imaging of the many organs including the skeleton and heart, as well as for whole body imaging for the detection of tumors. The use of tracers of cerebral perfusion and more recently brain neurotransmitter systems has resulted in the development of a number of applications for brain SPECT in neurology and psychiatry. Indications have been established in cases of dementia, epilepsy, neurovascular disorders, Parkinsonism, and following minor head trauma. It also has the potential to be a valuable research tool for the study of in vivo brain function. In this paper an overview will be given of the principles underlying Brain SPECT, the performance of the procedure, and its applications as a diagnostic modality and research tool.
Integrated positron emission tomography/computed tomography for evaluation of mediastinal lymph node staging of non-small-cell lung cancer in a tuberculosis-endemic area : a 5-year prospective observational study
(Health & Medical Publishing Group, 2015) Shaw, Jane A.; Irusen, Elvis M.; Von Groote-Bidlingmaier, Florian; Warwick, James M.; Jeremic, Branislav; Du Toit, Rudolf; Koegelenberg, Coenraad F. N.
Background. Integrated positron emission tomography/computed tomography (PET-CT) is a well-validated modality for assessing mediastinal lymph node metastasis in non-small-cell lung cancer (NSCLC), which determines management and predicts survival. Tuberculosis (TB) is known to lead to false-positive PET-CT findings. Objectives. To assess the diagnostic accuracy of PET-CT in identifying mediastinal lymph node involvement of NSCLC in a high TB-endemic area. Methods. Patients who underwent both PET-CT and lymph node tissue sampling for the investigation of suspected NSCLC were prospectively included in this observational study. Results were analysed per patient and per lymph node stage. A post-hoc analysis was performed to test the validity of a maximum standardised uptake value (SUVmax) cut-off for lymph node positivity. Results. PET-CT had a sensitivity of 92.6%, specificity of 48.6%, positive predictive value of 56.8% and negative predictive value (NPV) of 90.0% in the per-patient analysis. Diagnostic accuracy was 67.2%. Similar values were obtained in the per-lymph node stage analysis. TB was responsible for 21.1% of false-positive results. A SUVmax cut-off of 4.5 yielded an improvement in diagnostic accuracy from 64.0% to 84.7% compared with a cut-off of 2.5, but at the cost of decreasing the NPV from 90.6% to 83.5%. Conclusion. In a high TB-endemic area, PET-CT remains a valuable method for excluding mediastinal lymph node involvement in NSCLC. Patients with a negative PET-CT may proceed to definitive management without further invasive procedures. However, PET-CT-positive lymph nodes require pathological confirmation, and the possibility of TB must be considered.
Methamphetamine dependence with and without psychotic symptoms : a multi-modal brain imaging study
(Elsevier, 2018) Vuletica, Daniella; Dupontc, Patrick; Robertsond, Frances; Warwick, James M.; Zeevaartc, Jan Rijn; Steina, Dan J.
Objective: Methamphetamine dependence can lead to psychotic symptoms which may be mediated by frontal, striatal, limbic, and thalamic regions. There are few neuroimaging data that allow comparison of individuals with methamphetamine dependence who do, and do not, have psychosis. Two complementary imaging techniques were employed to investigate neurocircuitry associated with methamphetamine dependence with and without psychotic symptoms. Methods: Three groups of participants were recruited: methamphetamine dependent (MAA) (N=11), methamphetamine dependent with psychotic symptoms (MAP) (N=14), and controls (N=14). Resting brain glucose metabolism was measured using [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) and cerebral perfusion was assessed using arterial spin labelling (ASL) magnetic resonance imaging. Results: Methamphetamine abusers (MAA and MAP groups) had decreased glucose metabolism compared to healthy controls in the left insula, left precentral gyrus, and the anterior cingulate cortex. Compared to MAA participants, MAP participants had 1) decreased glucose metabolism in the left precentral gyrus and the left inferior frontal gyrus and 2) increased glucose metabolism in the putamen and pallidum. MAP participants also had increased cerebral perfusion in the right putamen and right pallidum compared to MAA. Conclusion: Findings support the involvement of frontal, striatal, and limbic regions in methamphetamine dependence. Furthermore, they indicate that glucose metabolism and cerebral perfusion in these regions are disrupted in methamphetamine dependent individuals with psychotic symptoms.
Nuclear medicine in South Africa
(HMPG, 2003-08) Warwick, James M.
ENGLISH ABSTRACT: Why should an issue of CME, a publication primarily directed at generalists, be devoted to nuclear medicine? I am reminded from time to time of how unfamiliar many of my colleagues are with this specialty, which is not surprising given the minimal coverage the field receives in already full undergraduate medical school programmes – even specialty-specific postgraduate exposure is often limited. Consequently, there is a paucity of knowledge of the role, indications, availability, and cost of many nuclear medicine procedures in the wider clinical community. Optimal nuclear medicine is heavily reliant on close collaboration with referring clinicians. Two prerequisites for a clear, useful report is a clear definition of the clinical question and the study being appropriate to answer that question. It is primarily the responsibility of nuclear medicine physicians to advise colleagues on what studies can do and, sometimes more importantly, cannot do.
Opsoclonus-myoclonus in an HIV-infected child on antiretroviral therapy-possible immune reconstitution inflammatory syndrome
(2005) van Toorn R.; Rabie H.; Warwick, James M.
The exact immunopathogenesis and neuroanatomical localization of opsoclonus-myoclonus ataxia syndrome remains unclear. We describe a 1 year 9 month old girl who, shortly after commencement of highly active antiretroviral therapy developed opsoclonus-myoclonus syndrome and subsequently died of disseminated cytomegalovirus infection. We postulate on the etiological factors that may have played a role in the disease pathogenesis of the patient's opsoclonus-myoclonus ataxia. Immune reconstitution inflammatory syndrome was considered the most likely because of the initial CD4 depletion and the onset of symptoms shortly after initiation of antiretroviral therapy. Single photon emission computed tomography (SPECT) proved helpful by localizing the area of dysfunction to the cerebellar vermis. © 2005 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.
PET-CT in brain disorders : the South African context
(AOSIS, 2021-11) Doruyter, Alexander G. G.; Parkes, Jeannette; Carr, Jonathan; Warwick, James M.
Positron emission tomography combined with X-ray computed tomography (PET-CT) has an established role in the management of brain disorders, but may be underutilised in South Africa. Possible barriers to access include the limited number of PET-CT facilities and the lack of contemporary guidelines for the use of brain PET-CT in South Africa. The current review aims to highlight the evidence-based usage of brain Positron emission tomography (PET) in dementia, movement disorders, brain tumours, epilepsy, neuropsychiatric lupus, immunemediated encephalitides, and brain infections. While being areas of research, there is currently no clinical role for the use of PET-CT in traumatic brain injury or in psychiatric or neurodevelopmental disorders. Strategies to expand the appropriate use of PET-CT in brain disorders are discussed in this article.
Quantitative 18F-FDG PET-CT scan characteristics correlate with tuberculosis treatment response
(SpringerOpen (part of Springer Nature), 2020-02-10) Malherbe, Stephanus T.; Chen, Ray Y.; Dupont, Patrick; Kant, Ilse; Kriel, Magdalena; Loxton, Andre G.; Smith, Bronwyn; Beltran, Caroline G. G.; Van Zyl, Susan; McAnda, Shirely; Abrahams, Charmaine; Maasdorp, Elizna; Doruyter, Alex; Via, Laura E.; Barry, Clifton E.; Alland, David; Richards, Stephanie G.; Ellman, Annare; Peppard, Thomas; Belisle, John; Tromp, Gerard; Ronacher, Katharina; Warwick, James M.; Winter, Jill; Walzl, Gerhard
Background: There is a growing interest in the use of F-18 FDG PET-CT to monitor tuberculosis (TB) treatment response. Tuberculosis lung lesions are often complex and diffuse, with dynamic changes during treatment and persisting metabolic activity after apparent clinical cure. This poses a challenge in quantifying scan-based markers of burden of disease and disease activity. We used semi-automated, whole lung quantification of lung lesions to analyse serial FDG PET-CT scans from the Catalysis TB Treatment Response Cohort to identify characteristics that best correlated with clinical and microbiological outcomes. Results: Quantified scan metrics were already associated with clinical outcomes at diagnosis and 1 month after treatment, with further improved accuracy to differentiate clinical outcomes after standard treatment duration (month 6). A high cavity volume showed the strongest association with a risk of treatment failure (AUC 0.81 to predict failure at diagnosis), while a suboptimal reduction of the total glycolytic activity in lung lesions during treatment had the strongest association with recurrent disease (AUC 0.8 to predict pooled unfavourable outcomes). During the first year after TB treatment lesion burden reduced; but for many patients, there were continued dynamic changes of individual lesions. Conclusions: Quantification of FDG PET-CT images better characterised TB treatment outcomes than qualitative scan patterns and robustly measured the burden of disease. In future, validated metrics may be used to stratify patients and help evaluate the effectiveness of TB treatment modalities.
Quantitative 18F-FDG PET-CT scan characteristics correlate with tuberculosis treatment response
(SpringerOpen (part of Springer Nature), 2020) Malherbe, Stephanus T.; Chen, Ray Y.; Dupont, Patrick; Kant, Ilse; Kriel, Magdalena; Loxton, Andre G.; Smith, Bronwyn; Beltran, Caroline G. G.; Van Zyl, Susan; McAnda, Shirely; Abrahams, Charmaine; Maasdorp, Elizna; Doruyter, Alex; Via, Laura E.; Barry, Clifton E.; Alland, David; Griffith- Richards, Stephanie; Ellman, Annare; Peppard, Thomas; Belisle, John; Tromp, Gerard; Ronacher, Katharina; Warwick, James M.; Winter, Jill; Walzl, Gerhard
Background: There is a growing interest in the use of F-18 FDG PET-CT to monitor tuberculosis (TB) treatment response. Tuberculosis lung lesions are often complex and diffuse, with dynamic changes during treatment and persisting metabolic activity after apparent clinical cure. This poses a challenge in quantifying scan-based markers of burden of disease and disease activity. We used semi-automated, whole lung quantification of lung lesions to analyse serial FDG PET-CT scans from the Catalysis TB Treatment Response Cohort to identify characteristics that best correlated with clinical and microbiological outcomes. Results: Quantified scan metrics were already associated with clinical outcomes at diagnosis and 1 month after treatment, with further improved accuracy to differentiate clinical outcomes after standard treatment duration (month 6). A high cavity volume showed the strongest association with a risk of treatment failure (AUC 0.81 to predict failure at diagnosis), while a suboptimal reduction of the total glycolytic activity in lung lesions during treatment had the strongest association with recurrent disease (AUC 0.8 to predict pooled unfavourable outcomes). During the first year after TB treatment lesion burden reduced; but for many patients, there were continued dynamic changes of individual lesions. Conclusions: Quantification of FDG PET-CT images better characterised TB treatment outcomes than qualitative scan patterns and robustly measured the burden of disease. In future, validated metrics may be used to stratify patients and help evaluate the effectiveness of TB treatment modalities.
A semi-automatic technique to quantify complex tuberculous lung lesions on 18F-fluorodeoxyglucose positron emission tomography/computerised tomography images
(Springer Open, 2018-06-25) Malherbe, Stephanus T.; Dupont, Patrick; Kant, Ilse; Ahlers, Petri; Kriel, Magdalena; Loxton, Andre G.; Chen, Ray Y.; Via, Laura E.; Thienemann, Friedrich; Wilkinson, Robert J; Barry, Clifton E.; Griffith-Richards, Stephanie; Ellman, Annare; Ronacher, Katharina; Winter, Jill; Walzl, Gerhard; Warwick, James M.
Background: There is a growing interest in the use of 18F-FDG PET-CT to monitor tuberculosis (TB) treatment response. However, TB causes complex and widespread pathology, which is challenging to segment and quantify in a reproducible manner. To address this, we developed a technique to standardise uptake (Z-score), segment and quantify tuberculous lung lesions on PET and CT concurrently, in order to track changes over time. We used open source tools and created a MATLAB script. The technique was optimised on a training set of five pulmonary tuberculosis (PTB) cases after standard TB therapy and 15 control patients with lesion-free lungs. Results: We compared the proposed method to a fixed threshold (SUV > 1) and manual segmentation by two readers and piloted the technique successfully on scans of five control patients and five PTB cases (four cured and one failed treatment case), at diagnosis and after 1 and 6 months of treatment. There was a better correlation between the Z-score-based segmentation and manual segmentation than SUV > 1 and manual segmentation in terms of overall spatial overlap (measured in Dice similarity coefficient) and specificity (1 minus false positive volume fraction). However, SUV > 1 segmentation appeared more sensitive. Both the Z-score and SUV > 1 showed very low variability when measuring change over time. In addition, total glycolytic activity, calculated using segmentation by Z-score and lesion-to-background ratio, correlated well with traditional total glycolytic activity calculations. The technique quantified various PET and CT parameters, including the total glycolytic activity index, metabolic lesion volume, lesion volumes at different CT densities and combined PET and CT parameters. The quantified metrics showed a marked decrease in the cured cases, with changes already apparent at month one, but remained largely unchanged in the failed treatment case. Conclusions: Our technique is promising to segment and quantify the lung scans of pulmonary tuberculosis patients in a semi-automatic manner, appropriate for measuring treatment response. Further validation is required in larger cohorts.
Should SPECT-CT replace SPECT for the evaluation of equivocal bone scan lesions in patients with underlying malignancies?
(2010) Ndlovu X.; George R.; Ellmann A.; Warwick, James M.
INTRODUCTION: Bone scintigraphy is used extensively in evaluating metastatic disease. There are currently no clear recommendations for the use of single photon emission computed tomography (SPECT)/CT in metastatic bone disease. Given its limited availability there is a need to identify the clinical indications for which SPECT/CT is clearly beneficial in influencing patient care and outcome. METHODS: Forty-two patients with equivocal lesions on planar scintigraphy were recruited and underwent SPECT/CT imaging. On reading of SPECT alone and then SPECT/CT, lesions were classified as malignant, benign or equivocal. Follow-up clinical information, radiological studies and/or bone scans were used as a gold standard. SPECT and SPECT/CT were compared in terms of the number of equivocal findings and accuracy on a patient-wise and lesion-wise basis. RESULTS: Forty-two patients with 189 skeletal lesions were examined. There was a diverse variety of primary tumours, with the majority being breast (n=22) and prostate cancer (n=8). SPECT/CT resulted in a significant reduction in the proportion of patients (48-14%, P=0.0015) and lesions (31-9%, P<0.0001) with equivocal findings. The overall accuracy of SPECT/CT was significantly higher on both a patient-wise (52-79%, P=0.0026) and lesion-wise basis (67-92%, P<0.0001). CONCLUSION: SPECT/CT significantly outperforms SPECT alone for the interpretation of skeletal lesions in patients undergoing bone scanning for metastases. When available SPECT/CT is indicated in patients in whom correct classification of equivocal lesions is expected to alter the patient's management. © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins.

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