A Artéria de Adamkiewicz é a maior artéria radiculomedular anterior que alcança a artéria espinal anterior, sendo responsável pelo suprimento sanguíneo de até dois terços distais da medula espinal. Uma lesão desta artéria durante um procedimento cirúrgico implica em graves complicações como paresia de membros inferiores e também paraplegia, muitas vezes de caráter definitivo, podendo acontecer durante a realização do tratamento cirúrgico de aneurismas toracoabdominais e patologias da coluna vertebral. Geralmente a artéria de Adamkiewicz está localizada entre a oitava vértebra torácica e a primeira lombar. Os exames de angiotomografia computadorizada da medula espinal e angioressonância magnética são métodos seguros, não invasivos e amplamente utilizados para identificá-la. Esta investigação teve como objetivo avaliar a Artéria de Adamkiewicz através da Angiotomografia Computadorizada Coronariana de Múltiplos Detectores acoplado ao Eletrocardiograma. Por meio de estudo prospectivo, foram analisados 86 exames de angiotomografia coronariana. Os exames foram analisados por dois investigadores independentes e a confiabilidade inter e intraobservador das variáveis nível de origem e lado de entrada foi avaliada. Os resultados evidenciaram uma taxa de identificação da artéria de Adamkiewicz em 71 (82,5%) exames. O nível de origem foi identificado entre T9 e T11 em 56 (79,2%) exames. Em relação ao lado, em 65 (91,5%) pacientes o lado de entrada foi o lado esquerdo. O exame de angiotomografia computadorizada coronariana de Múltiplos Detectores acoplado ao Eletrocardiograma mostrou taxas de identificação da artéria de Adamkiewicz semelhantes aos encontrados nos exames de angiografia, angiotomografia computadorizada e angioressonância da medula espinal / The Adamkiewicz artery is the most important radiculomedular artery that reaches the anterior spinal artery and is responsible for blood supply to distal two thirds of the spinal cord. An injury to this artery during a surgical procedure involves serious complications such as paresis of lower limbs and also paraplegia, often permanently, which may happen during the surgical treatment of thoracoabdominal aneurysms and pathologies of the spine. Usually the Adamkiewicz artery is located between the eighth thoracic vertebra and the first lumbar. Computed tomography angiography scans and spinal magnetic resonance angiography are safe methods, non-invasive and widely used to identify it. This research aimed to evaluate the artery of Adamkiewicz by Computed Coronary Tomography Angiography with multiple detectors coupled to Electrocardiogram. In a prospective study, we analyzed 86 exams of Computed Coronary Tomography Angiography. The exams were analyzed by two independent researchers and the inter and intraobserver reliability of the variables source level and entrance side was evaluated. The results showed an identification rate of Adamkiewicz artery in 71 (82.5%) examinations. The level of origin was identified between T9 and T11 in 56 (79.2%) examinations. In relation to the side, in 65 (91.5%) patients had the entrance side on the left side. Adamkiewicz artery evaluation by Angiotomography Coronary Computed with Multiple detectors coupled to Electrocardiogram showed Adamkiewicz artery identification rates similar to those found in angiography examinations, computadorized tomography angiography and magnetic resonance angiography of the spinal cord

Introdução: A angiotomografia computadorizada (angioTC) de tórax é utilizada para diagnosticar tromboembolia pulmonar (TEP). O papel deste exame para estabelecer diagnósticos alternativos, quando negativo para TEP, não é bem conhecido. Objetivos: Estudar a contribuição da angioTC para identificar um diagnóstico alternativo nos casos com angioTC negativa para TEP, assim como determinar a prevalência de TEP e comparar as características clínicas dos pacientes com e sem TEP. Pacientes e Métodos: Estudo transversal, retrospectivo, com 191 pacientes adultos que realizaram angioTC de tórax por suspeita de TEP, no período de setembro de 2009 a maio de 2012. A angioTC e a radiografia de tórax foram revisadas para determinar se os achados poderiam fornecer um diagnóstico alternativo nos casos com angioTC negativa para TEP. Do prontuário eletrônico foram coletados dados relacionados a sintomas, fatores de risco, comorbidades, tempo de internação e mortalidade. Resultados: Dos 191 pacientes incluídos, 128 (67%) eram mulheres. A média de idade foi 59,3 ± 17,1 anos. Em 59,2% a angioTC do tórax foi solicitada no serviço de emergência. A angioTC foi positiva para TEP em 47 pacientes (24,6% dos casos). Achados anormais na angioTC de tórax foram observados em 120 dos 144 pacientes com angioTC negativa para TEP, predominando atelectasia (48,6%), nódulo pulmonar (30,6%), derrame pleural (29,9%) e consolidação (21,5%). Os achados da angioTC foram compatíveis com um diagnóstico alternativo, que explicava os sintomas do paciente, em 39,3% (n=75); esta percentagem reduziu para 20,4% (n=39) quando foram considerados somente os casos sem achados semelhantes na radiografia de tórax. O diagnóstico alternativo mais frequente, identificado somente pela angioTC, foi pneumonia (20 de 39 casos). Não houve diferença nos sintomas, fatores de risco, comorbidades e taxa de óbito intrahospitalar no grupo com angioTC positiva e negativa para TEP. Pacientes com angioTC positiva para TEP tiveram um maior tempo de internação (mediana de 18 dias vs 9,5 dias; p=0,001). Conclusões: A angioTC de tórax foi positiva para TEP em 24,6% dos casos. Não houve diferença significativa nos achados clínicos dos pacientes com angioTC positiva e negativa para TEP, exceto por um tempo de internação maior no grupo com TEP. A angioTC de tórax mostrou achados compatíveis com um diagnóstico alternativo em 39,3% dos pacientes. Entretanto, estes achados não haviam sido detectados na radiografia de tórax em 20,4% dos casos. O diagnóstico alternativo mais frequente foi pneumonia. / Introduction: Computed tomography (CT) pulmonary angiography is used to diagnose pulmonary embolism (PE). The role of this test in establishing an alternative diagnosis, when negative for PE, is not well known. Aims: To study the contribution of CT angiography in establishing alternative diagnoses, when the test is negative for PE, as well as to determine the prevalence of PE and compare the clinical characteristics of patients with and without PE. Patients and Methods: Cross-sectional, retrospective study of 191 adult consecutive patients who underwent CT angiography for suspected PE, from September, 2009 to May, 2012. The CT angiographies and chest radiographies were reviewed to determine whether the findings could provide an alternative diagnosis in cases with negative CT angiography for PE. Symptoms, risk factors, comorbidities, length of stay and mortality were collected from the electronic medical record. Results: Of the 191 patients included 128 (67%) were women. The mean age of de patients was 59.3 ± 17.1 years. In 59.2% CT angiography was requested in the emergency room. The CT angiography was positive for PE in 47 patients (24.6% of the total cases). Abnormal findings, observed in 120 of the 144 patients with negative CT angiography for PE, were predominantly atelectasis (48.6%), pulmonary nodules (30.6%), pleural effusion (29.9%) and consolidation (21.5%). CT angiography findings were consistent with a diagnosis that explained the patient's symptoms in 39.3% (n=75). When only those cases without concurrent findings on chest radiography were considered this percentage dropped to 20.4% (n=39). The most common alternative diagnosis, identified only by CT angiography, was pneumonia (20 of 39 cases). There were no differences between the groups with positive and negative CT angiography for PE in terms of symptoms, risk factors, comorbidities, and in-hospital death rate. However, patients with positive CT angiography for PE had a longer hospital stay (median 18 days vs. 9.5 days, p=0.001). Conclusions: CT angiography was positive for PE in 24.6% of cases. There were no significant differences in the clinical findings of patients with positive and negative CT angiography for PE, except for a longer hospital stay in the former group. Chest CT angiography revealed findings consistent with an alternative diagnosis in 39.3 % of the patients. However, these findings were not detected on chest radiography in 20.4 % of the patients. The most common alternative diagnosis was pneumonia.

Introdução: A angiotomografia computadorizada (angioTC) de tórax é utilizada para diagnosticar tromboembolia pulmonar (TEP). O papel deste exame para estabelecer diagnósticos alternativos, quando negativo para TEP, não é bem conhecido. Objetivos: Estudar a contribuição da angioTC para identificar um diagnóstico alternativo nos casos com angioTC negativa para TEP, assim como determinar a prevalência de TEP e comparar as características clínicas dos pacientes com e sem TEP. Pacientes e Métodos: Estudo transversal, retrospectivo, com 191 pacientes adultos que realizaram angioTC de tórax por suspeita de TEP, no período de setembro de 2009 a maio de 2012. A angioTC e a radiografia de tórax foram revisadas para determinar se os achados poderiam fornecer um diagnóstico alternativo nos casos com angioTC negativa para TEP. Do prontuário eletrônico foram coletados dados relacionados a sintomas, fatores de risco, comorbidades, tempo de internação e mortalidade. Resultados: Dos 191 pacientes incluídos, 128 (67%) eram mulheres. A média de idade foi 59,3 ± 17,1 anos. Em 59,2% a angioTC do tórax foi solicitada no serviço de emergência. A angioTC foi positiva para TEP em 47 pacientes (24,6% dos casos). Achados anormais na angioTC de tórax foram observados em 120 dos 144 pacientes com angioTC negativa para TEP, predominando atelectasia (48,6%), nódulo pulmonar (30,6%), derrame pleural (29,9%) e consolidação (21,5%). Os achados da angioTC foram compatíveis com um diagnóstico alternativo, que explicava os sintomas do paciente, em 39,3% (n=75); esta percentagem reduziu para 20,4% (n=39) quando foram considerados somente os casos sem achados semelhantes na radiografia de tórax. O diagnóstico alternativo mais frequente, identificado somente pela angioTC, foi pneumonia (20 de 39 casos). Não houve diferença nos sintomas, fatores de risco, comorbidades e taxa de óbito intrahospitalar no grupo com angioTC positiva e negativa para TEP. Pacientes com angioTC positiva para TEP tiveram um maior tempo de internação (mediana de 18 dias vs 9,5 dias; p=0,001). Conclusões: A angioTC de tórax foi positiva para TEP em 24,6% dos casos. Não houve diferença significativa nos achados clínicos dos pacientes com angioTC positiva e negativa para TEP, exceto por um tempo de internação maior no grupo com TEP. A angioTC de tórax mostrou achados compatíveis com um diagnóstico alternativo em 39,3% dos pacientes. Entretanto, estes achados não haviam sido detectados na radiografia de tórax em 20,4% dos casos. O diagnóstico alternativo mais frequente foi pneumonia. / Introduction: Computed tomography (CT) pulmonary angiography is used to diagnose pulmonary embolism (PE). The role of this test in establishing an alternative diagnosis, when negative for PE, is not well known. Aims: To study the contribution of CT angiography in establishing alternative diagnoses, when the test is negative for PE, as well as to determine the prevalence of PE and compare the clinical characteristics of patients with and without PE. Patients and Methods: Cross-sectional, retrospective study of 191 adult consecutive patients who underwent CT angiography for suspected PE, from September, 2009 to May, 2012. The CT angiographies and chest radiographies were reviewed to determine whether the findings could provide an alternative diagnosis in cases with negative CT angiography for PE. Symptoms, risk factors, comorbidities, length of stay and mortality were collected from the electronic medical record. Results: Of the 191 patients included 128 (67%) were women. The mean age of de patients was 59.3 ± 17.1 years. In 59.2% CT angiography was requested in the emergency room. The CT angiography was positive for PE in 47 patients (24.6% of the total cases). Abnormal findings, observed in 120 of the 144 patients with negative CT angiography for PE, were predominantly atelectasis (48.6%), pulmonary nodules (30.6%), pleural effusion (29.9%) and consolidation (21.5%). CT angiography findings were consistent with a diagnosis that explained the patient's symptoms in 39.3% (n=75). When only those cases without concurrent findings on chest radiography were considered this percentage dropped to 20.4% (n=39). The most common alternative diagnosis, identified only by CT angiography, was pneumonia (20 of 39 cases). There were no differences between the groups with positive and negative CT angiography for PE in terms of symptoms, risk factors, comorbidities, and in-hospital death rate. However, patients with positive CT angiography for PE had a longer hospital stay (median 18 days vs. 9.5 days, p=0.001). Conclusions: CT angiography was positive for PE in 24.6% of cases. There were no significant differences in the clinical findings of patients with positive and negative CT angiography for PE, except for a longer hospital stay in the former group. Chest CT angiography revealed findings consistent with an alternative diagnosis in 39.3 % of the patients. However, these findings were not detected on chest radiography in 20.4 % of the patients. The most common alternative diagnosis was pneumonia.

Introdução: A angiotomografia computadorizada (angioTC) de tórax é utilizada para diagnosticar tromboembolia pulmonar (TEP). O papel deste exame para estabelecer diagnósticos alternativos, quando negativo para TEP, não é bem conhecido. Objetivos: Estudar a contribuição da angioTC para identificar um diagnóstico alternativo nos casos com angioTC negativa para TEP, assim como determinar a prevalência de TEP e comparar as características clínicas dos pacientes com e sem TEP. Pacientes e Métodos: Estudo transversal, retrospectivo, com 191 pacientes adultos que realizaram angioTC de tórax por suspeita de TEP, no período de setembro de 2009 a maio de 2012. A angioTC e a radiografia de tórax foram revisadas para determinar se os achados poderiam fornecer um diagnóstico alternativo nos casos com angioTC negativa para TEP. Do prontuário eletrônico foram coletados dados relacionados a sintomas, fatores de risco, comorbidades, tempo de internação e mortalidade. Resultados: Dos 191 pacientes incluídos, 128 (67%) eram mulheres. A média de idade foi 59,3 ± 17,1 anos. Em 59,2% a angioTC do tórax foi solicitada no serviço de emergência. A angioTC foi positiva para TEP em 47 pacientes (24,6% dos casos). Achados anormais na angioTC de tórax foram observados em 120 dos 144 pacientes com angioTC negativa para TEP, predominando atelectasia (48,6%), nódulo pulmonar (30,6%), derrame pleural (29,9%) e consolidação (21,5%). Os achados da angioTC foram compatíveis com um diagnóstico alternativo, que explicava os sintomas do paciente, em 39,3% (n=75); esta percentagem reduziu para 20,4% (n=39) quando foram considerados somente os casos sem achados semelhantes na radiografia de tórax. O diagnóstico alternativo mais frequente, identificado somente pela angioTC, foi pneumonia (20 de 39 casos). Não houve diferença nos sintomas, fatores de risco, comorbidades e taxa de óbito intrahospitalar no grupo com angioTC positiva e negativa para TEP. Pacientes com angioTC positiva para TEP tiveram um maior tempo de internação (mediana de 18 dias vs 9,5 dias; p=0,001). Conclusões: A angioTC de tórax foi positiva para TEP em 24,6% dos casos. Não houve diferença significativa nos achados clínicos dos pacientes com angioTC positiva e negativa para TEP, exceto por um tempo de internação maior no grupo com TEP. A angioTC de tórax mostrou achados compatíveis com um diagnóstico alternativo em 39,3% dos pacientes. Entretanto, estes achados não haviam sido detectados na radiografia de tórax em 20,4% dos casos. O diagnóstico alternativo mais frequente foi pneumonia. / Introduction: Computed tomography (CT) pulmonary angiography is used to diagnose pulmonary embolism (PE). The role of this test in establishing an alternative diagnosis, when negative for PE, is not well known. Aims: To study the contribution of CT angiography in establishing alternative diagnoses, when the test is negative for PE, as well as to determine the prevalence of PE and compare the clinical characteristics of patients with and without PE. Patients and Methods: Cross-sectional, retrospective study of 191 adult consecutive patients who underwent CT angiography for suspected PE, from September, 2009 to May, 2012. The CT angiographies and chest radiographies were reviewed to determine whether the findings could provide an alternative diagnosis in cases with negative CT angiography for PE. Symptoms, risk factors, comorbidities, length of stay and mortality were collected from the electronic medical record. Results: Of the 191 patients included 128 (67%) were women. The mean age of de patients was 59.3 ± 17.1 years. In 59.2% CT angiography was requested in the emergency room. The CT angiography was positive for PE in 47 patients (24.6% of the total cases). Abnormal findings, observed in 120 of the 144 patients with negative CT angiography for PE, were predominantly atelectasis (48.6%), pulmonary nodules (30.6%), pleural effusion (29.9%) and consolidation (21.5%). CT angiography findings were consistent with a diagnosis that explained the patient's symptoms in 39.3% (n=75). When only those cases without concurrent findings on chest radiography were considered this percentage dropped to 20.4% (n=39). The most common alternative diagnosis, identified only by CT angiography, was pneumonia (20 of 39 cases). There were no differences between the groups with positive and negative CT angiography for PE in terms of symptoms, risk factors, comorbidities, and in-hospital death rate. However, patients with positive CT angiography for PE had a longer hospital stay (median 18 days vs. 9.5 days, p=0.001). Conclusions: CT angiography was positive for PE in 24.6% of cases. There were no significant differences in the clinical findings of patients with positive and negative CT angiography for PE, except for a longer hospital stay in the former group. Chest CT angiography revealed findings consistent with an alternative diagnosis in 39.3 % of the patients. However, these findings were not detected on chest radiography in 20.4 % of the patients. The most common alternative diagnosis was pneumonia.

A Artéria de Adamkiewicz é a maior artéria radiculomedular anterior que alcança a artéria espinal anterior, sendo responsável pelo suprimento sanguíneo de até dois terços distais da medula espinal. Uma lesão desta artéria durante um procedimento cirúrgico implica em graves complicações como paresia de membros inferiores e também paraplegia, muitas vezes de caráter definitivo, podendo acontecer durante a realização do tratamento cirúrgico de aneurismas toracoabdominais e patologias da coluna vertebral. Geralmente a artéria de Adamkiewicz está localizada entre a oitava vértebra torácica e a primeira lombar. Os exames de angiotomografia computadorizada da medula espinal e angioressonância magnética são métodos seguros, não invasivos e amplamente utilizados para identificá-la. Esta investigação teve como objetivo avaliar a Artéria de Adamkiewicz através da Angiotomografia Computadorizada Coronariana de Múltiplos Detectores acoplado ao Eletrocardiograma. Por meio de estudo prospectivo, foram analisados 86 exames de angiotomografia coronariana. Os exames foram analisados por dois investigadores independentes e a confiabilidade inter e intraobservador das variáveis nível de origem e lado de entrada foi avaliada. Os resultados evidenciaram uma taxa de identificação da artéria de Adamkiewicz em 71 (82,5%) exames. O nível de origem foi identificado entre T9 e T11 em 56 (79,2%) exames. Em relação ao lado, em 65 (91,5%) pacientes o lado de entrada foi o lado esquerdo. O exame de angiotomografia computadorizada coronariana de Múltiplos Detectores acoplado ao Eletrocardiograma mostrou taxas de identificação da artéria de Adamkiewicz semelhantes aos encontrados nos exames de angiografia, angiotomografia computadorizada e angioressonância da medula espinal / The Adamkiewicz artery is the most important radiculomedular artery that reaches the anterior spinal artery and is responsible for blood supply to distal two thirds of the spinal cord. An injury to this artery during a surgical procedure involves serious complications such as paresis of lower limbs and also paraplegia, often permanently, which may happen during the surgical treatment of thoracoabdominal aneurysms and pathologies of the spine. Usually the Adamkiewicz artery is located between the eighth thoracic vertebra and the first lumbar. Computed tomography angiography scans and spinal magnetic resonance angiography are safe methods, non-invasive and widely used to identify it. This research aimed to evaluate the artery of Adamkiewicz by Computed Coronary Tomography Angiography with multiple detectors coupled to Electrocardiogram. In a prospective study, we analyzed 86 exams of Computed Coronary Tomography Angiography. The exams were analyzed by two independent researchers and the inter and intraobserver reliability of the variables source level and entrance side was evaluated. The results showed an identification rate of Adamkiewicz artery in 71 (82.5%) examinations. The level of origin was identified between T9 and T11 in 56 (79.2%) examinations. In relation to the side, in 65 (91.5%) patients had the entrance side on the left side. Adamkiewicz artery evaluation by Angiotomography Coronary Computed with Multiple detectors coupled to Electrocardiogram showed Adamkiewicz artery identification rates similar to those found in angiography examinations, computadorized tomography angiography and magnetic resonance angiography of the spinal cord

Objective: A malignant profile of early brain ischemia has been demonstrated in the Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution (DEFUSE) trial. Patients with a malignant profile had a low chance for an independent functional outcome despite thrombolysis within 3–6 h. We sought to determine whether CT angiography (CTA) could identify a malignant imaging profile within 3 h from symptom onset. Methods: We studied consecutive patients (04/02–09/07) with anterior circulation stroke who received CTA before intravenous thrombolysis within 3 h. We assessed the Alberta Stroke Program Early CT Score (ASPECTS) on CTA source images (CTASI). Intracranial thrombus burden on CTA was assessed with a novel 10-point clot burden score (CBS). We analyzed percentages independent (modified Rankin Scale score ≤2) and fatal outcome at 3 months and parenchymal hematoma rates across categorized combined CTASI-ASPECTS + CBS score groups where 20 is best and 0 is worst. Results: We identified 114 patients (median age 73 years [interquartile range 61–80], onset-to-tPA time 129 min [95–152]). Among 24 patients (21%) with extensive hypoattenuation on CTASI and extensive thrombus burden (combined score ≤10), only 4% (1/24) were functionally independent whereas mortality was 50% (12/24). In contrast, 57% (51/90) of patients with less affected scores (combined score 11–20) were functionally independent and mortality was 10% (9/90; p < 0.001). Parenchymal hematoma rates were 30% (7/23) vs. 8% (7/88), respectively (p = 0.008). Conclusion: CTA identifies a large hyperacute stroke population with high mortality and low likelihood for independent functional outcome despite early thrombolysis. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Modern medical imaging techniques have revolutionized health care over the last decades, providing clinicians with high-resolution 3D images of the inside of the patient's body without the need for invasive procedures. Detailed images of the vascular anatomy can be captured by angiography, providing a valuable source of information when deciding whether a vascular intervention is needed, for planning treatment, and for analyzing the success of therapy. However, increasing level of detail in the images, together with a wide availability of imaging devices, lead to an urgent need for automated techniques for image segmentation and analysis in order to assist the clinicians in performing a fast and accurate examination. To reduce the need for user interaction and increase the speed of vascular segmentation,  we propose a fast and fully automatic vascular skeleton extraction algorithm. This algorithm first analyzes the volume's intensity histogram in order to automatically adapt the internal parameters to each patient and then it produces an approximate skeleton of the patient's vasculature. The skeleton can serve as a seed region for subsequent surface extraction algorithms. Further improvements of the skeleton extraction algorithm include the expansion to detect the skeleton of diseased arteries and the design of a convolutional neural network classifier that reduces false positive detections of vascular cross-sections. In addition to the complete skeleton extraction algorithm, the thesis presents a segmentation algorithm based on modified onion-kernel region growing. It initiates the growing from the previously extracted skeleton and provides a rapid binary segmentation of tubular structures. To provide the possibility of extracting precise measurements from this segmentation we introduce a method for obtaining a segmentation with subpixel precision out of the binary segmentation and the original image. This method is especially suited for thin and elongated structures, such as vessels, since it does not shrink the long protrusions. The method supports both 2D and 3D image data. The methods were validated on real computed tomography datasets and are primarily intended for applications in vascular segmentation, however, they are robust enough to work with other anatomical tree structures after adequate parameter adjustment, which was demonstrated on an airway-tree segmentation.

Η CT αγγειογραφία εγκεφάλου (CTA) είναι μέθοδος καθιερωμένη για την διερεύνηση και την θεραπεία των ενδοκρανιακών ανευρυσμάτων. Σκοπός της μελέτης μας ήταν η σύγκριση των ευρημάτων της ψηφιακής αγγειογραφίας (DSA) με αυτά της CTA και με τα χειρουργικά ευρήματα σε ασθενείς με οξεία υπαραχνοειδή αιμορραγία, καθώς επίσης και η αξιολόγηση της κλινικής χρησιμότητας της μεθόδου. Κατά την διάρκεια τριών ετών, 82 ασθενείς προσήλθαν με κλινική εικόνα και σημειολογία συμβατή με υπαραχνοειδή αιμορραγία. Η CTA έγινε αμέσως μετά την απλή CT, ενώ η DSA εντός των πρώτων 48 ωρών από την εισαγωγή. Όλα τα ανευρύσματα που ευρέθησαν με τις δύο μεθόδους υπεβλήθησαν σε χειρουργική αποκατάσταση ή ενδαγγειακό εμβολισμό. Σε όσους ασθενείς βρέθηκε αρνητικό αποτέλεσμα και με τις δύο μεθόδους, έγινε επαναληπτική DSA 15 ημέρες μετά το επεισόδιο με σκοπό την επιβεβαίωση της απουσίας ανευρύσματος. Οι CTA εξετάσεις καθώς και οι κλασσικές αγγειογραφίες μελετήθηκαν από μια ομάδα δύο ακτινολόγων για κάθε τεχνική, οι οποίοι έπρεπε να καταγράψουν την ύπαρξη ή μη ανευρύσματος, να περιγράψουν τα χαρακτηριστικά του και να αξιολογήσουν την μέθοδο. Χειρουργική ή και ενδαγγειακή θεραπεία έγινε σε 45 ασθενείς και ανευρέθησαν 53 ανευρύσματα. Χρησιμοποιώντας την CTA, ευρέθησαν 47 ανευρύσματα σε 42 ασθενείς. Η DSA ανίχνευσε 43 ανευρύσματα σε 39 ασθενείς. Η ευαισθησία της CTA για τον εντοπισμό όλων των ανευρυσμάτων με βάση το χειρουργικό/θεραπευτικό αποτέλεσμα ήταν 88,7%, η ειδικότητα 100%, η θετική προβλεπτική αξία (PPV) 100%, η αρνητική προβλεπτική αξία (NPV) 80,7% και η ακρίβεια 92,3%. Αντίστοιχα, η ευαισθησία της DSA ήταν 87,8%, η ειδικότητα 98%, η PPV 97,7%, η NPV 89,1% και η ακρίβεια 92,9%. Όσον αφορά στα ανευρύσματα ≥3 mm, η CTA είχε ευαισθησία που κυμαινόταν μεταξύ 93,3 έως 100%, ίση με αυτή της DSA. Η CTA εμφάνισε τα ίδια ποσοστά ευαισθησίας με αυτά της DSA σε ανευρύσματα ≥3 mm. Εμφάνισε επίσης 100% ποσοστό ανίχνευσης σε ανευρύσματα της πρόσθιας αναστομωτικής και του διχασμού της μέσης εγκεφαλικής αρτηρίας, ενώ μερικές εντοπίσεις όπως η οπίσθια αναστομωτική αρτηρία παραμένουν προβληματικές. 80 Κατά την διάρκεια της παρούσας μελέτης προσπαθήσαμε να δημιουργήσουμε μια τεχνική προσομοίωσης της διεγχειρητικής εικόνας των ραγέντων ενδοκρανιακών ανευρυσμάτων, με τη χρήση volume rendering techniques σε εικόνες που προκύπτουν από CT αγγειογραφία. Η τρισδιάστατη κατασκευή των εικόνων προέκυψε από την συνεργασία μιας ομάδας αποτελούμενης από τέσσερις ακτινολόγους, έναν νευροχειρουργό και έναν ιατρικό φυσικό. Το αποτέλεσμα αυτής της συνεργασίας ήταν η παραγωγή μιας εικόνας οριοθετημένης στο χώρο, με οδηγά σημεία που εύκολα μπορούσαν να αναπαραχθούν κατά την διάρκεια του χειρουργείου. Οι εικόνες χειρουργικής προσομοίωσης ενός ανευρύσματος είναι πιθανώς χρήσιμο εργαλείο για τον προεγχειρητικό σχεδιασμό των ενδοκρανιακών ανευρυσμάτων. / Cerebral CT angiography is an established method applied to both the detection and treatment planning of intracranial aneurysms. The aim of our study was to compare DSA to CTA findings and with the surgical results mainly in patients with acute SAH and to evaluate the clinical usefulness of CTA. During the last three years, 82 consecutive patients were admitted under clinical symptoms and signs suggestive of harbouring an intracranial aneurysm. CT angiography performed immediately afterwards the plain CT, while DSA was performed within the first 48 hours of admission. All aneurysms detected, were confirmed during surgery or endovascular embolization. Repeat DSA was performed in all patients having both the initial CTA and the DSA 15 days after the onset of symptoms negative. CT angiograms and conventional angiographies were studied by a consensus of two radiologists for each technique, who performed aneurysm detection, morphological features characterization and evaluation of the technique. Surgical or/and endovascular treatment was performed in 45 patients and 53 aneurysms were confirmed. Using 3D-CT angiography we detected 47 aneurysms in 42 patients. Conventional angiography depicted 43 aneurysms in 39 patients. The sensitivity of CTA for the detection of all aneurysms versus surgery was 88.7%, the specificity 100%, the positive predictive value (PPV) 100%, the negative predictive value (NPV) 80.7% and the accuracy 92.3%. Consequently, the sensitivity of DSA was 87.8%, the specificity 98%, the PPV 97.7%, the NPV 89.1% and the accuracy 92.9%. Considering the aneurysms ≥ 3 mm, CTA showed a sensitivity ranging from 93.3% to 100%, equal to that of DSA. Cerebral CT angiography has an equal sensitivity to DSA in the detection of intracranial aneurysms greater than 3 mm. It has also 100% detection rate in AcoA and MCA bifurcation aneurysms, while some locations like posterior communicating artery aneurysms remain problematic. The delineating features of each aneurysm are better depicted with CTA due to 3D visualization. The use of Digital Subtraction Angiography as a diagnostic tool can be limited in equivocal cases. A supplement to the above work is our effort to describe a technique for simulating the surgical view of ruptured intracranial aneurysms, using volume 82 rendering techniques in spiral CT angiography data. The 3D rendered images were assessed by a team consisted of four radiologists, one neurosurgeon and one medical physicist. The resultant ‘surgical view’ image was standardized in space using a three-dimensional coordinate system, which allowed for its reproduction in the operating theatre. The surgical views are easily reproducible and αποτελούν a useful tool for the surgical planning of intracranial aneurysms.

Thirty-four patients with acute hemispheric ischemic strokes underwent both CT angiography and contrast-enhanced transcranial color-coded duplexsonography (TCCD) to study the effectiveness of the combined noninvasive techniques for evaluation of the circle of Willis. In 3/34 patients, CT angiography and contrast-enhanced TCCD demonstrated middle cerebral artery (MCA) occlusion, in 5 others MCA stenosis. A severe posterior cerebral artery stenosis was missed by CT angiography. In 8 patients, contrast-enhanced TCCD failed because of poor bone windows. In these patients, CT angiography was normal. CT angiography and contrast-enhanced TCCD are complementary noninvasive diagnostic tools. Disagreements between the diagnostic findings of these methods still need further evaluation by digital subtraction angiography. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

This thesis explores two possible ways of detecting soft plaque present in the coronary arteries, using CTA imagery. The coronary arteries are vessels that supply oxidized blood to the cardiac muscle and are thus important for the proper functioning of heart. Cholesterol or reactive oxygen species from cigarette smoke and other toxins may get adhered to the walls of coronary arteries and trigger chronic inflammation that leads to formation of the soft plaque. When the soft plaque grows bigger in volume, it occludes the blood flow to the cardiac muscle and finally results in ischemic heart attack. Moreover, smaller plaque can easily rupture due to the blood flow in arteries and can result in complications such as stroke. Hence there is a need to detect the soft plaque using non-invasive or minimally invasive techniques. In CTA imagery, the cardiac muscle appears as a dark gray color, while the blood appears as dull white color and the the calcified plaque appears as bright white. The soft plaque has an intensity which falls between the intensity level of the blood and cardiac muscle, making it difficult to directly segment the soft plaque using standard segmentation methods. Soft plaque in its advanced stages forms a concavity in the blood lumen. A watershed based segmentation method was used to detect the presence of this concavity which in turn identifies the location of the soft plaque. For segmenting the soft plaque at its earlier stages, a novel segmentation technique was used. In this technique the surface is evolved based on a region-based energy calculated in the local neighborhood around each point on the evolving surface. This method seems to be superior to the watershed based segmentation method in detecting smaller plaque deposits.