Thesis (PhD)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Although transthoracic ultrasonography is a well established modality, it is still underutilised by chest physicians. The aim of this research project was to investigate the feasibility, diagnostic yield and safety of ultrasound(US)-assisted transthoracic biopsies performed by clinicians in various settings relevant to daily practice of respiratory medicine. We conducted four clinical trials which are summarised below: 1. In a prospective study on the feasibility of US-assisted transthoracic fine needle aspiration (TTFNA) of drowned lung secondary to a proximal mass lesion, a novel indication for US-assisted TTFNA was described. TTFNA passes >20mm from the visceral pleura had a sensitivity of 74.2% and were also more likely to contain malignant cells than more superficial passes. The surprisingly high yield and the fact that no serious complications were observed validated this approach, which may be an alternative to bronchoscopy. 2. In the largest single-centre study on US-assisted TTFNA with rapid on-site evaluation (ROSE) and cutting needle biopsy (CNB) in the setting of superior vena cava (SVC) syndrome ever reported, we were able to accurately diagnose 96% of all patients who presented with an associated mass lesion that abutted or infiltrated the chest wall. No pneumothoraces or major haemorrhage was caused. We also validated the single-session approach, and were able to conclude that US-assisted TTFNA (with ROSE) is the initial investigation of choice in suspected bronchogenic carcinoma, whereas both TTFNA and CNB need to be performed in all other cases. 3. We continued to validate the novel single-session sequential approach in a study on anterosuperior mediastinal masses. US-assisted TTFNA with ROSE was performed on 45 consecutive patients, immediately followed by CNB where a provisional diagnosis of epithelial carcinoma or probable tuberculosis (TB) could not be established. An accurate cytological diagnosis was made in 73.3%, and was more likely to be diagnostic in epithelial carcinoma and TB than all other pathology (p<0.001). CNB yielded a diagnosis in 88.2%. Overall 93.3% of patients were diagnosed by the single-session approach. No pneumothorax or major haemorrhage was observed. 4. In a prospective study, we compared US-assisted Abrams and Tru-Cut needle biopsies with regard to their yield for pleural TB. Pleural biopsy specimens obtained with Abrams needles contained pleural tissue in 91.0% of cases and were diagnostic in 81.8%, whereas Tru-Cut needle biopsy specimens only contained pleural tissue in 78.7% (p=0.015) and were diagnostic in 65.2% (p=0.022). In conclusion, we investigated the feasibility of US-assisted biopsies performed by respiratory physicians in various settings, and consistently found acceptable to very high diagnostic yields with minimal complications. Furthermore, we were able to validate a novel indication for US-assisted TTFNA (US-assisted TTFNA of drowned lung), validate the use of a single-session sequential approach (USassisted TTFNA with ROSE followed by CNB where indicated) in at least two clinical settings (SVC syndrome and anterosuperior mediastinal masses) and we were able to show that US-assisted Abrams needle biopsy is superior to Tru-Cut needles biopsy when histological confirmation of TB pleuritis is required. / AFRIKAANSE OPSOMMING: Alhoewel transtorakale ultrasonografie ‘n gevestigde modaliteit is, word dit onderbenut deur pulmonoloë. Die doel van hierdie navorsingsprojek was om die praktiese uitvoerbaarheid, diagnostiese opbrengs en veiligheid van sonargerigte transtorakale biopsies uitgevoer deur klinici in verskeie situasies relevant tot die alledaagse praktyk te ontleed. Ons het vier kliniese proewe uitgevoer wat hieronder opgesom word: 1. In ‘n prospektiewe studie oor die praktiese uitvoerbaarheid van sonargerigte transtorakale fyn naald aspirasie (TTFNA) van areas van obstruktiewe pneumonitis sekondêr tot proksimale massa letsels, is ‘n nuwe indikasie vir sonargerigte TTFNA beskryf. TTFNA aspirasies wat >20mm van die visserale pleura geneem is, het ‘n sensitiwiteit van 74.2% gehad en was meer geneig om maligne selle op te lewer as meer oppervlakkige aspirasies. Die verbasende hoë diagnostiese sensitiwiteit en afwesigheid van ernstige komplikasies het die praktiese waarde van hierdie benadering bevestig. 2. In die grootste studie nog oor sonargerigte TTFNA met spoedige in-teater evalusies (SITE) en sny-naald biopsie (SNB) in die teenwoordigheid van superior vena cava (SVC) sindroom, kon ons 96% van pasiënte wat presenteer het met ‘n geassosieerde massa letsel wat die borskaswand betrek, akkuraat diagnoseer. Geen pneumotoraks of major bloeding is waargeneem nie. Ons kon ook die praktiese uitvoerbaarheid van ‘n enkelsessie benadering bevestig en kon tot die gevolgtrekking kom dat sonargerigte TTFNA (met SITE) die aanvanklike ondersoek van keuse is waar bronguskarsinoom vermoed word, maar dat beide TTFNA en SNB noodsaaklik is in ander gevalle. 3. Ons het voortgegaan om die waarde van die nuwe enkel-sessie benadering te bevestig in ‘n studie oor antero-superior mediastinale massas. Sonargerigte TTFNA met SITE is uitgevoer op 45 pasiënte en in gevalle waar ‘n voorlopige diagnose van epiteliale karsinoom of waarskynlike tuberkulose (TB) nie bevestig kon word nie, is dit onmiddelik gevolg deur SNB. ‘n Akkurate sitologiese diagnose is gemaak in 73.3% van gevalle en meer algemeen in epiteliale karsinoom en TB as ander patologie (p<001). SNB was diagnosties in 88.2%. In 93.3% kon ‘n diagnose verkry word met die enkel-sessie benadering. Geen pneumotoraks of major bloeding is waargeneem nie. 4. In ‘n prospektiewe studie is sonargerigte Abrams naald en Tru-Cut naald biopsies se opbrengs vir pleurale TB met mekaar vergelyk. Pleurale biopsie monsters wat met ‘n Abrams naalde geneem is, het pleurale weefsel in 91.0% gevalle getoon en was diagnosties in 81.8%, vergeleke met Tru-Cut naalde wat slegs in 87.7% pleurale weefsel opgelewer het (p=0.015) en wat net in in 65.2% diagnosties was (p=0.022). Opsommend het ons die praktiese uitvoerbaarheid van sonargerigte biopsies uitgevoer deur pulmonoloë in veskeie kliniese situasies nagevors, en het deurlopend aanvaarbare tot hoë diagnostiese opbrengste gevind met minimale komplikasies. Verder kon ons ‘n nuwe indikasie vir sonargerigte TTFNA beskryf en evalueer (sonargerigte TTFNA van obstruktiewe pneumonitis); ‘n enkel-sessie sekwensiële benadering se waarde bevestig (sonargerigte TTFNA met SITE, gevolg deur SNB waar aangedui) in ten minste twee kliniese situasies (SVC sindroom en anterosuperior mediastinale massas); en was dit moontlik om te bewys dat UK-geleide Abrams naald biopsies superior tot Tru-cut naald biopsies is in die histologiese bevestiging van TB pleuritis.

In der vorliegenden Studie wurden die prä- und postoperativen transthorakalen echokardiographischen Untersuchungen von 31 Patienten mit Mitralklappenrekonstruktion im Zeitraum von 2007 bis 2011 retrospektiv analysiert. Es wurden die Untersuchungen eingeschlossen, bei denen sowohl vor als auch nach dem operativen Eingriff das Bilddatenmaterial komplett zur Verfügung stand. Die echokardiographische Dokumentation der im klinischen Alltag durchgeführten Untersuchungen ermöglichte die Evaluation der Dimensionen von rechten und linken Ventrikel sowie beider Vorhöfe, der systolischen und diastolischen linksventrikulären Funktion, der Morphologie der Herzklappen sowie der pulmonalarteriellen Drücke. Die Patientenkohorte wurde zusätzlich in Subgruppen nach Symptomatik, nach additiven chirurgischen Interventionen und nach dem Vorliegen von chronischem Vorhofflimmern analysiert. Die Ergebnisse der Mitralklappenrekonstruktion zeigten erwartungsgemäß postoperativ eine signifikante Reduktion des Schweregrades der Mitralklappenregurgitation, eine Verkleinerung der linksseitigen Herzhöhlen, eine Normalisierung der linksventrikulären Pumpfunktion und der pulmonalarteriellen Drücke. Asymptomatische Patienten im Sinusrhythmus mit isolierter Mitralklappenrekonstruktion hatten die günstigsten postoperativen echokardiographischen Ergebnisse. Weiterhin war eine postoperativ eingeschränkte rechtsventrikuläre und linksventrikuläre diastolische Funktion zu postulieren. Ein mit fast 20% beträchtlicher Anteil der Patienten mit einer postoperativen Vena contracta der Mitralklappenregurgitation ≥ 3mm war vermutlich auf eine Vorselektion der Patienten zurückzuführen. Schlussfolgernd sollte eine Mitralklappenrekonstruktion möglichst vor Eintreten irreversibler kardialer Schädigungen durchgeführt werden.

Introdução: Embora a imagem com segunda harmônica esteja largamente disponível na maioria dos aparelhos de ultra-sonografia, sua acurácia para avaliar a morfologia e a função do apêndice atrial esquerdo (AAE) permanece precariamente caracterizada. Objetivos: Explorar o desempenho diagnóstico da ecocardiografia transtorácica com segunda harmônica (ETTsh) na avaliação do AAE após eventos neurológicos agudos. Métodos: Realizamos um estudo transversal em pacientes com eventos neurológicos isquêmicos agudos, encaminhados para realização de ETTsh e Ecocardiografia Transesofágica (ETE). As análises da área longitudinal máxima e do pico da velocidade de esvaziamento de fluxo do AAE foram realizadas por observadores cegos. Resultados: Foram avaliados 51 pacientes (49% femininas, 62 ± 12 anos) com eventos neurológicos isquêmicos agudos. Contraste ecocardiográfico espontâneo foi observado em 11 (22%) pacientes no AE, em 7(14%) no AAE e em 3 (6%) na aorta torácica descendente. Trombo no AAE foi identificado em apenas 2 (4%) pacientes. O mapeamento e a análise do AAE foi factível na maioria dos casos (98%), tanto para o estudo com Doppler quanto para avaliação da área do AAE. Observamos uma associação positiva e significativa entre o ETTsh e o ETE, tanto para a avaliação das velocidades máximas de esvaziamento do AAE (r=0,63; p<0,001) quanto para a área longitudinal máxima do AAE (r=0,73; p<0,001). Ademais, todos os pacientes com trombos no AAE ou contraste espontâneo (n=7) tiveram velocidade de esvaziamento inferior a 50 cm/s no mapeamento transtorácico (valor preditivo negativo de 100%). Na análise multivariada ajustada para diversos potenciais preditores transtorácicos de risco, a velocidade máxima de esvaziamento do AAE permaneceu independentemente associada com trombos no AAE ou contraste espontâneo. Conclusão: ETTsh pode fornecer informações relevantes a respeito da morfologia e dinâmica do AAE. Em particular, pacientes com velocidades altas de esvaziamento do AAE podem não necessitar de avaliação adicional com ETE. / Background. Although second harmonic imaging is widely available in most ultrasound systems, its accuracy to evaluate the left atrial appendage (LAA) morphology and function remains poorly characterized. Objectives. To explore the performance of second harmonic transthoracic echocardiography (shTTE) in the assessment of LAA after acute neurologic events. Methods. We conducted a cross-sectional survey of patients with acute ischemic neurologic events that underwent both shTTE and transesophageal echocardiography (TEE). Blinded off-line analysis of LAA maximal area and peak emptying velocities were performed. Results. Fifty-one consecutive patients (49% females, 62 ± 12 years) with acute ischemic neurologic events were evaluated. Spontaneous echocardiographic contrast was observed in 11(22%) patients in the LA, in 7(14%) in the LAA and in 3 (6%) in the thoracic aorta. LAA thrombus was identified in only 2(4%) patients. Scanning and analysis of the LAA was feasible in most patients (98%) both for Doppler and LAA area assessment. We observed a positive and significant association between shTTE and TEE assessment of both LAA peak emptying velocities (r=0.63, p<0.001) and LAA maximum area (r=0.73, p<0.001). In addition, all patients (n=7) with LAA thrombus or spontaneous contrast had peak emptying velocities inferior to 50 cm/s on transthoracic scanning (negative predictive value of 100%). In multivariate analysis adjusted for several potential transthoracic predictors of risk, LAA peak-emptying velocity remained independently associated with LAA thrombus or spontaneous contrast. Conclusions. shTTE can provide valuable information of LAA morphology and dynamic. In particular, patients with high peak emptying velocities might not need additional TEE imaging.

Introdução: Embora a imagem com segunda harmônica esteja largamente disponível na maioria dos aparelhos de ultra-sonografia, sua acurácia para avaliar a morfologia e a função do apêndice atrial esquerdo (AAE) permanece precariamente caracterizada. Objetivos: Explorar o desempenho diagnóstico da ecocardiografia transtorácica com segunda harmônica (ETTsh) na avaliação do AAE após eventos neurológicos agudos. Métodos: Realizamos um estudo transversal em pacientes com eventos neurológicos isquêmicos agudos, encaminhados para realização de ETTsh e Ecocardiografia Transesofágica (ETE). As análises da área longitudinal máxima e do pico da velocidade de esvaziamento de fluxo do AAE foram realizadas por observadores cegos. Resultados: Foram avaliados 51 pacientes (49% femininas, 62 ± 12 anos) com eventos neurológicos isquêmicos agudos. Contraste ecocardiográfico espontâneo foi observado em 11 (22%) pacientes no AE, em 7(14%) no AAE e em 3 (6%) na aorta torácica descendente. Trombo no AAE foi identificado em apenas 2 (4%) pacientes. O mapeamento e a análise do AAE foi factível na maioria dos casos (98%), tanto para o estudo com Doppler quanto para avaliação da área do AAE. Observamos uma associação positiva e significativa entre o ETTsh e o ETE, tanto para a avaliação das velocidades máximas de esvaziamento do AAE (r=0,63; p<0,001) quanto para a área longitudinal máxima do AAE (r=0,73; p<0,001). Ademais, todos os pacientes com trombos no AAE ou contraste espontâneo (n=7) tiveram velocidade de esvaziamento inferior a 50 cm/s no mapeamento transtorácico (valor preditivo negativo de 100%). Na análise multivariada ajustada para diversos potenciais preditores transtorácicos de risco, a velocidade máxima de esvaziamento do AAE permaneceu independentemente associada com trombos no AAE ou contraste espontâneo. Conclusão: ETTsh pode fornecer informações relevantes a respeito da morfologia e dinâmica do AAE. Em particular, pacientes com velocidades altas de esvaziamento do AAE podem não necessitar de avaliação adicional com ETE. / Background. Although second harmonic imaging is widely available in most ultrasound systems, its accuracy to evaluate the left atrial appendage (LAA) morphology and function remains poorly characterized. Objectives. To explore the performance of second harmonic transthoracic echocardiography (shTTE) in the assessment of LAA after acute neurologic events. Methods. We conducted a cross-sectional survey of patients with acute ischemic neurologic events that underwent both shTTE and transesophageal echocardiography (TEE). Blinded off-line analysis of LAA maximal area and peak emptying velocities were performed. Results. Fifty-one consecutive patients (49% females, 62 ± 12 years) with acute ischemic neurologic events were evaluated. Spontaneous echocardiographic contrast was observed in 11(22%) patients in the LA, in 7(14%) in the LAA and in 3 (6%) in the thoracic aorta. LAA thrombus was identified in only 2(4%) patients. Scanning and analysis of the LAA was feasible in most patients (98%) both for Doppler and LAA area assessment. We observed a positive and significant association between shTTE and TEE assessment of both LAA peak emptying velocities (r=0.63, p<0.001) and LAA maximum area (r=0.73, p<0.001). In addition, all patients (n=7) with LAA thrombus or spontaneous contrast had peak emptying velocities inferior to 50 cm/s on transthoracic scanning (negative predictive value of 100%). In multivariate analysis adjusted for several potential transthoracic predictors of risk, LAA peak-emptying velocity remained independently associated with LAA thrombus or spontaneous contrast. Conclusions. shTTE can provide valuable information of LAA morphology and dynamic. In particular, patients with high peak emptying velocities might not need additional TEE imaging.

Introdução: Embora a imagem com segunda harmônica esteja largamente disponível na maioria dos aparelhos de ultra-sonografia, sua acurácia para avaliar a morfologia e a função do apêndice atrial esquerdo (AAE) permanece precariamente caracterizada. Objetivos: Explorar o desempenho diagnóstico da ecocardiografia transtorácica com segunda harmônica (ETTsh) na avaliação do AAE após eventos neurológicos agudos. Métodos: Realizamos um estudo transversal em pacientes com eventos neurológicos isquêmicos agudos, encaminhados para realização de ETTsh e Ecocardiografia Transesofágica (ETE). As análises da área longitudinal máxima e do pico da velocidade de esvaziamento de fluxo do AAE foram realizadas por observadores cegos. Resultados: Foram avaliados 51 pacientes (49% femininas, 62 ± 12 anos) com eventos neurológicos isquêmicos agudos. Contraste ecocardiográfico espontâneo foi observado em 11 (22%) pacientes no AE, em 7(14%) no AAE e em 3 (6%) na aorta torácica descendente. Trombo no AAE foi identificado em apenas 2 (4%) pacientes. O mapeamento e a análise do AAE foi factível na maioria dos casos (98%), tanto para o estudo com Doppler quanto para avaliação da área do AAE. Observamos uma associação positiva e significativa entre o ETTsh e o ETE, tanto para a avaliação das velocidades máximas de esvaziamento do AAE (r=0,63; p<0,001) quanto para a área longitudinal máxima do AAE (r=0,73; p<0,001). Ademais, todos os pacientes com trombos no AAE ou contraste espontâneo (n=7) tiveram velocidade de esvaziamento inferior a 50 cm/s no mapeamento transtorácico (valor preditivo negativo de 100%). Na análise multivariada ajustada para diversos potenciais preditores transtorácicos de risco, a velocidade máxima de esvaziamento do AAE permaneceu independentemente associada com trombos no AAE ou contraste espontâneo. Conclusão: ETTsh pode fornecer informações relevantes a respeito da morfologia e dinâmica do AAE. Em particular, pacientes com velocidades altas de esvaziamento do AAE podem não necessitar de avaliação adicional com ETE. / Background. Although second harmonic imaging is widely available in most ultrasound systems, its accuracy to evaluate the left atrial appendage (LAA) morphology and function remains poorly characterized. Objectives. To explore the performance of second harmonic transthoracic echocardiography (shTTE) in the assessment of LAA after acute neurologic events. Methods. We conducted a cross-sectional survey of patients with acute ischemic neurologic events that underwent both shTTE and transesophageal echocardiography (TEE). Blinded off-line analysis of LAA maximal area and peak emptying velocities were performed. Results. Fifty-one consecutive patients (49% females, 62 ± 12 years) with acute ischemic neurologic events were evaluated. Spontaneous echocardiographic contrast was observed in 11(22%) patients in the LA, in 7(14%) in the LAA and in 3 (6%) in the thoracic aorta. LAA thrombus was identified in only 2(4%) patients. Scanning and analysis of the LAA was feasible in most patients (98%) both for Doppler and LAA area assessment. We observed a positive and significant association between shTTE and TEE assessment of both LAA peak emptying velocities (r=0.63, p<0.001) and LAA maximum area (r=0.73, p<0.001). In addition, all patients (n=7) with LAA thrombus or spontaneous contrast had peak emptying velocities inferior to 50 cm/s on transthoracic scanning (negative predictive value of 100%). In multivariate analysis adjusted for several potential transthoracic predictors of risk, LAA peak-emptying velocity remained independently associated with LAA thrombus or spontaneous contrast. Conclusions. shTTE can provide valuable information of LAA morphology and dynamic. In particular, patients with high peak emptying velocities might not need additional TEE imaging.

京都大学 / 新制・論文博士 / 博士(医学) / 乙第13584号 / 論医博第2304号 / 新制||医||1070(附属図書館) / (主査)教授 江木 盛時, 教授 湊谷 謙司, 教授 江藤 浩之 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

Abstract: Background: At present, device closure of interatrial communication has become a well established technique in order to adequately treat severe left-to-right shunt associated with ASDs. During the traditional procedure, fluoroscopy with the waist of a compliant balloon is used to determine the appropriate size of the closure device and defect sizing. Choice of adequate closure device using transthoracic echocardiography (TTE) has been hitherto unreported. Methods & Materials: Between December 2002 and October 2004, 40 patients (15 males, 25 females, mean age; 11.7 ¡Ó 7.8 years ) with secundum ASDs underwent transcatheter closure at our institution. In group 1, 30 patients had the procedure by balloon sizing and TTE sizing. In 10 patients (group 2), TTE sizing was used as the sole too l for selecting device size and the device size was chosen to be based on the Amplatzer septal occluder ( ASO ) size and TTE size ratio in group 1. The procedure was performed under continuous transoesophageal echocardiographic monitor with general anesthesia. Results: The correlation was found between TTE and stretched balloon sizing diameter SBD ( y= 1.2645x-1.4465; R&#x00B2;=0.9861 ), and between TTE size and ASO size ( y = 1.3412x-1.2864; R&#x00B2;=0.9929 ) in group 1. In group 2, statistical correlation between TTE and ASO ( y=1.3419x-0.1172; R&#x00B2;=0.9934 ) was also found. Good linear regression between TTE size and ASO chosen size was noted in group 1 and group 2 (R&#x00B2;=0.99).In group 2, successful device implantation was accomplished in all patients whose device size was chosen to be based on the ASO and TTE ratio in group 1. Conclusions: TTE sizing is a safe and ideal method to measure interatrial defect and choose the occluding device respectively. With our experience, the sizing based on the TTE is generally easier than measurement from the balloon sizing.

In der vorliegenden Studie wurden die prä- und postoperativen transthorakalen echokardiographischen Untersuchungen von 31 Patienten mit Mitralklappenrekonstruktion im Zeitraum von 2007 bis 2011 retrospektiv analysiert. Es wurden die Untersuchungen eingeschlossen, bei denen sowohl vor als auch nach dem operativen Eingriff das Bilddatenmaterial komplett zur Verfügung stand. Die echokardiographische Dokumentation der im klinischen Alltag durchgeführten Untersuchungen ermöglichte die Evaluation der Dimensionen von rechten und linken Ventrikel sowie beider Vorhöfe, der systolischen und diastolischen linksventrikulären Funktion, der Morphologie der Herzklappen sowie der pulmonalarteriellen Drücke. Die Patientenkohorte wurde zusätzlich in Subgruppen nach Symptomatik, nach additiven chirurgischen Interventionen und nach dem Vorliegen von chronischem Vorhofflimmern analysiert. Die Ergebnisse der Mitralklappenrekonstruktion zeigten erwartungsgemäß postoperativ eine signifikante Reduktion des Schweregrades der Mitralklappenregurgitation, eine Verkleinerung der linksseitigen Herzhöhlen, eine Normalisierung der linksventrikulären Pumpfunktion und der pulmonalarteriellen Drücke. Asymptomatische Patienten im Sinusrhythmus mit isolierter Mitralklappenrekonstruktion hatten die günstigsten postoperativen echokardiographischen Ergebnisse. Weiterhin war eine postoperativ eingeschränkte rechtsventrikuläre und linksventrikuläre diastolische Funktion zu postulieren. Ein mit fast 20% beträchtlicher Anteil der Patienten mit einer postoperativen Vena contracta der Mitralklappenregurgitation ≥ 3mm war vermutlich auf eine Vorselektion der Patienten zurückzuführen. Schlussfolgernd sollte eine Mitralklappenrekonstruktion möglichst vor Eintreten irreversibler kardialer Schädigungen durchgeführt werden.

Stress cardiomyopathy can cause significant morbidity in the functional life of patients. The most common finding is apical ballooning of the left ventricle on cardiac catheterization. Some cases present with atypical imaging findings. This report presents a case of atypical stress cardiomyopathy with midventricular hypokinesis.

Background: Patent Foramen Ovale (PFO), a remnant of the foetal circulation, is emerging as a new cause of disease. It has been found to be associated with cryptogenic stroke in young adults, peripheral arterial embolism and neurological decompression sickness in divers. The detection of PFO remains a diagnostic challenge; transoesophageal echocardiogram being currently considered the ‘gold standard’. The development of a non-invasive technique is crucial for the identification of a venous-to-arterial shunt (v-aCS) which may permit paradoxical embolism. Little is known about the genetic basis of PFO and our limited knowledge is based on animal studies and gene mutations detected in patients with other cardiac septal defects. Methods: Study 1: PFO Detection and Evaluation: This study was designed to evaluate transcranial Doppler (TCD), transthoracic echocardiogram (TTE) and transoesophageal echocardiogram (TOE) with administration of contrast via arm and femoral veins. We then developed a standardized protocol for PFO detection and quantification using TCD. Study 2: PFO and Migraine: The PFO detection protocol developed from the first study formed the diagnostic technique to detect v-aCS in an adequately powered matched case control study to explore the association between PFO and migraine. Study 3: The Genetic basis of PFO: This study was designed to explore the genetic basis of a PFO using a candidate gene approach. Results: Study 1 - PFO Detection Study: When compared with TOE with femoral vein contrast injection as the ‘gold standard’, TCD with arm vein contrast was 100% sensitive and 97.4% specific for detecting a PFO. We defined a PFO positive (+ve) study on TCD as > 15 microbubbles entering the cerebral circulation, on TCD following arm vein injection and >16 microbubbles with a femoral contrast injection. A ‘major’ PFO+ve v-aCS was defined as >35 microbubbles with arm vein injection or >90 microbubbles with femoral vein injection. We then developed a new diagnostic pathway for PFO detection in clinical practice. Study 2 - PFO Migraine study: A significant difference in prevalence of v-aCS between migraine with aura M+A) and their matched controls was demonstrated with adjusted OR=3.72 (1.48-9.38) p=0.005 for a PFO+ve v-aCS, and a highly significant difference between M+A and controls for a ‘major’ PFO+ve v-aCS with adjusted OR = 6.38 (1.89 – 21.48) p = 0.003. There was significant association with APC resistance and migraine on thrombophilia screen. Study 3 - The PFO Genetics Study: This study detected mutations of GATA4 and NKX2-5 in both PFO+ve cases and PFO-ve controls. Two novel non synonymous mutations of GATA4, c.461T>A and c.994G>A were found only in PFO positive individuals and may be associated with a PFO. All the PFO+ve cases with a GATA4 gene mutation had a major PFO+ve v-aCSConclusion:TCD detects PFO with a sensitivity of 100% and specificity of 92.3% and is the most reliable non-invasive technique for PFO detection. When arm vein injections are used both cough and valsalva provocation is essential. There was a highly significant association between PFO+ve v- aCS and M+A, especially with a ‘major’ PFO+ve v-aCS. GATA 4 mutations though infrequent were found PFO+ve cases and all had major v-aCS.