Advances in imaging chest tuberculosis: blurring of differences between children and adults

This article reviews the ongoing role of imaging in the diagnosis of tuberculosis (TB) and its complications. A modern imaging classification of TB, taking into account both adults and children and the blurring of differences in the presentation patterns, must be absorbed into daily practice. Clinicians must not only be familiar with imaging features of TB but also become expert at detecting these when radiologists are unavailable. Communication between radiologists and clinicians with regard to local constraints, patterns of disease, human immunodeficiency virus (HIV) coinfection rates, and imaging parameters relevant for management (especially in drug resistance programs) is paramount for making an impact with imaging, and preserving clinician confidence. Recognition of special imaging, anatomic and vulnerability differences between children and adults is more important than trying to define patterns of disease exclusive to children

An edge-driven 3D region growing approach for upper airways morphology and volume evaluation in patients with Pierre Robin sequence

In this paper, a semi-automatic approach for segmentation of the upper airways is proposed. The implemented approach uses an edge-driven 3D region-growing algorithm to segment ROIs and 3D volume-rendering technique to reconstruct the 3D model of the upper airways. This method can be used to integrate information inside a medical decision support system, making it possible to enhance medical evaluation. The effectiveness of the proposed segmentation approach was evaluated using Jaccard (92.1733%) and dice (94.6441%) similarity indices and specificity (96.8895%) and sensitivity (97.6682%) rates. The proposed method achieved an average computation time reduced by a 16x factor with respect to manual segmentation

Comparison of coronal minimum intensity projection CT reconstructions with flexible bronchoscopy for airway compression in children with Lymphobronchial TB

A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Medicine in Diagnostic Radiology Johannesburg 2017.INTRODUCTION Tuberculosis (TB) remains one of the most important causes of morbidity and mortality in children in Africa, as well as the rest of the world. Lymphobronchial TB (LBTB) occurs when tuberculous adenopathy affects the airways, either by direct involvement (inflammation and erosion) or by indirect involvement (compression and stenosis). Endobronchial TB (EBTB) is the inflammation of the tracheobronchial tree, which is caused by tuberculosis, and is secondary to the rupture of lymph nodes into the bronchi, or the extension thereof to the peribronchial region, by lymphatic drainage. Identification of airway compromise due to any of these processes can be performed invasively using flexible bronchoscopy or non-invasively with CT scanning, including post processing techniques such as minimum intensity projections (MinIP). AIM This retrospective study aimed to generate standardised coronal minimum intensity projection (MinIP) CT reconstructions, and compare these with fibreoptic bronchoscopy in children with LBTB. METHOD Standardised coronal MinIP reconstructions were performed from CT scans in children with LBTB and the findings of three readers were compared with flexible bronchoscopy (FB), regarding airway abnormalities. Intraluminal lesions, the site of the stenosis, and the degree of stenosis were evaluated. The length of stenosis was evaluated by CT MinIP only, and no comparison to FB has been made. RESULTS 65 children with LBTB met the inclusion criteria (38 males; 58.5% and 27 females; 41.5%), with ages ranging from 2.5 to 144 months. Coronal CT MinIP demonstrated a sensitivity of 96% and specificity of 89% against FB. The most common site of stenosis was the bronchus intermedius (91%), followed by the left main bronchus (85%), the right upper lobe bronchus RUL (66%), and the trachea (60%). Agreement between coronal CT MinIP and FB ranged from 36.9% at the carina to 84.6% at the RLL in normal and abnormal airways. CONCLUSION This study has proven that a standardised coronal CT MinIP reconstruction is useful in demonstrating airway stenosis in children with lymphobronchial TB, with sensitivity of up to 96% and specificity up to 89%. The most common sites of stenosis found by the coronal MinIP CT reconstruction were the BI (91%), followed by the LMB (85%), the RUL (66%), and the trachea (60%). The coronal CT MinIP had additional advantages over FB in that it allowed objective measurement of the diameter of the stenosis, measurement of the length of the stenosis as well as visualisation of the post-stenotic segments of the airways. CT MinIP was also able to provide information about lung parenchymal abnormalities. Standardised coronal MinIP reconstructions are easily performed, as described in our paper, and should be provided with each set of cross sectional MDCT images in children with LBTB. This one single image can provide easily appreciable and useful airway information and additional information not available from FB.LG201

Multidetector row CT for imaging the paediatric tracheobronchial tree

The introduction of multidetector row computed tomography (MDCT) scanners has altered the approach to imaging the paediatric thorax. In an environment where the rapid acquisition of CT data allows general hospitals to image children instead of referring them to specialist paediatric centres, it is vital that general radiologists have access to protocols appropriate for paediatric applications. Thus a dramatic reduction in the delivered radiation dose is ensured with optimal contrast bolus delivery and timing, and inappropriate repetition of the scans is avoided. This article focuses on the main principles of volumetric CT imaging that apply generically to all MDCT scanners. We describe the reconstruction techniques for imaging the paediatric thorax and the low-dose protocols used in our institution on a 16-slice detector CT scanner. Examples of the commonest clinical applications are also given

64-Channel multi-detector row CT angiographic evaluation of the micropigs for potential living donor lung transplantation

Micropigs are the most likely source animals for xenotransplantation. However, an appropriate method for evaluating the lung of micropigs had not been established. Therefore, this study was performed to evaluate the feasibility of 64-channel multi-detector row computed tomography (MDCT) to measure the diameter of the pulmonary arteries and the lung volume in micropigs. The mean diameters of the trachea, and left and right bronchi were 1.6 ± 0.17, 1.18 ± 0.14, and 1.1 ± 0.11 cm, respectively. The mean diameters of the main, right, and left pulmonary arteries were 1.38 ± 0.09, 1.07 ± 0.26, and 0.98 ± 0.13 cm and the diameters of right, left, and common inferior pulmonary veins were 0.97 ± 0.20, 0.76 ± 0.20, and 1.99 ± 0.26 cm, respectively. The mean lung volume was 820.3 ± 77.11 mL. The data presented in this study suggest that the MDCT may be a noninvasive, rapid, and accurate investigational method for pulmonary anatomy in living lung donors

SEMI-AUTOMATIC VOLUMETRIC SEGMENTATION OF THE UPPER AIRWAYS IN PATIENTS WITH PIERRE ROBIN SEQUENCE

Pierre Robin malformation is a rare craniofacial dysmorphism whose pathogenesis is multifactorial. Although there is some agreement in non-invasive treatment in less severe cases, the dispute is still open on cases with severe respiratory impairment. We present a semi-automatic novel diagnostic tool for calculating upper airway volume, in order to eventually address surgery in patients with Pierre Robin Sequence (PRS). Multidetector CT datasets of two patients and two controls were tested to assess the proposed method for ROI segmentation, upper airway volume computation and three-dimensional reconstructions. The experimental results show an irregular pattern and a severely reduced cross-sectional area (CSA) with a mean value of 8.3808 mm(2) in patients with PRS and a mean CSA value of 33.7692 mm(2) in controls (a ΔCSA of about -75%). Moreover, the similarity indexes and sensitivity/specificity values obtained showed a good segmentation performance. In particular, mean values of Jaccard and Dice similarity indexes were 91.69% and 94.07%, respectively, while the mean values of specificity and sensitivity were 96.69% and 98.03%, respectively. The proposed tool represents an easy way to perform a quantitative analysis of airway volume and useful 3D reconstructions

Semi-Automatic Measurement of the Airway Dimension by Computed Tomography Using the Full-Width-Half-Maximum Method: a Study on the Measurement Accuracy according to the CT Parameters and Size of the Airway

Objective: To assess the influence of variable factors such as the size of the airway and the CT imaging parameters such as the reconstruction kernel, field-ofview (FOV), and slice thickness on the automatic measurement of airway dimension. Materials and Methods: An airway phantom was fabricated that contained eleven poly-acryl tubes of various lumen diameters and wall thicknesses. The measured density of the poly-acryl wall was 150 HU, and the measured density of the airspace filled with polyurethane foam was 900 HU. CT images were obtained using a 16-MDCT (multidetector CT) scanner and were reconstructed with various reconstruction kernels, thicknesses and FOV. The luminal radius and wall thickness were measured using in-house software based on the fullwidth- half-maximum method. The measured values as determined by CT and the actual dimensions of the tubes were compared. Results: Measurements were most accurate on images reconstructed with use of a standard kernel (mean error: 0.03+-0.21 mm for wall thickness and 0.12 0.11 mm for the luminal radius). There was no significant difference in accuracy among images with the use of variable slice thicknesses or a variable FOV. Below a 1-mm threshold, the measurement failed to represent the change of the real dimensions. Conclusion: Measurement accuracy was strongly influenced by the specific reconstruction kernel utilized. For accurate measurement, standardization of the imaging protocol and selection of the appropriate anatomic level are essential.This work was supported by a Korea Science and Engineering Foundation (KOSEF) grant funded by the Korea government (MOST) (No. R01-2006-000-11244-0)

Towards an Efficient Gas Exchange Monitoring with Electrical Impedance Tomography - Optimization and validation of methods to investigate and understand pulmonary blood flow with indicator dilution

In vielen Fällen sind bei Patienten, die unter stark gestörtem Gasaustausch der Lunge leiden, die regionale Lungenventilation und die Perfusion nicht aufeinander abgestimmt. Besonders bei Patienten mit akutem Lungenversagen sind sehr heterogene räumliche Verteilungen von Belüftung und Perfusion der Lunge zu beobachten. Diese Patienten müssen auf der Intensivstation künstlich beatmet und überwacht werden, um einen ausreichenden Gasaustausch sicherzustellen. Bei schweren Lungenverletzungen ist es schwierig, durch die Anwendung hoher Beatmungsdrücke und -volumina eine optimale Balance zwischen dem Rekrutieren kollabierter Regionen zu finden, und gleichzeitig die Lunge vor weiterem Schaden durch die von außen angelegten Drücke zu schützen. Das Interesse für eine bettseitige Messung und Darstellung der regionalen Belüftungs- und Perfusionsverteilung für den Einsatz auf der Intensivstation ist in den letzten Jahren stark gestiegen, um eine lungenprotektive Beatmung zu ermöglichen und klinische Diagnosen zu vereinfachen. Die Elektrische-Impedanztomographie (EIT) ist ein nicht-invasives, strahlungsfreies und sehr mobil einsetzbares System. Es bietet eine hohe zeitliche Abtastung und eine funktionelle räumliche Auflösung, die es ermöglicht, dynamische (patho-) physiologische Prozesse zu visualisieren und zu überwachen. Die medizinische Forschung an EIT hat sich dabei hauptsächlich auf die Schätzung der räumlichen Belüftung konzentriert. Kommerziell erhältliche Systeme haben gezeigt, dass die EIT eine wertvolle Entscheidungshilfe während der mechanischen Beatmung darstellt. Allerdings ist die Abschätzung der pulmonalen Perfusion mit EIT noch nicht etabliert. Dies könnte das fehlende Glied sein, um die Analyse des pulmonalen Gasaustauschs am Krankenbett zu ermöglichen. Obwohl einige Publikationen die prinzipielle Machbarkeit der indikatorgestützten EIT zur Schätzung der räumlichen Verteilung des pulmonalen Blutflusses gezeigt haben, müssen diese Methoden optimiert und durch Vergleich mit dem Goldstandard des Lungenperfusions-Monitorings validiert werden. Darüber hinaus ist weitere Forschung notwendig, um zu verstehen welche physiologischen Informationen der EIT-Perfusionsschätzung zugrunde liegen. Mit der vorliegenden Arbeit soll die Frage beantwortet werden, ob bei der klinischen Anwendung von EIT neben der regionalen Belüftung auch räumliche Informationen des pulmonalen Blutflusses geschätzt werden können, um damit potenziell den pulmonalen Gasaustausch am Krankenbett beurteilen zu können. Die räumliche Verteilung der Perfusion wurde durch Bolusinjektion einer leitfähigen Kochsalzlösung als Indikator geschätzt, um die Verteilung des Indikators während seines Durchgangs durch das Gefäßsystem der Lunge zu verfolgen. Verschiedene dynamische EIT-Rekonstruktionsmethoden und Perfusionsparameter Schätzmethoden wurden entwickelt und verglichen, um den pulmonalen Blutfluss robust beurteilen zu können. Die geschätzten regionalen EIT-Perfusionsverteilungen wurden gegen Goldstandard Messverfahren der Lungenperfusion validiert. Eine erste Validierung wurde anhand von Daten einer tierexperimentellen Studie durchgeführt, bei der die Multidetektor-Computertomographie als vergleichende Lungenperfusionsmessung verwendet wurde. Darüber hinaus wurde im Rahmen dieser Arbeit eine umfassende präklinische Tierstudie durchgeführt, um die Lungenperfusion mit indikatorverstärkter EIT und Positronen-Emissions-Tomographie während mehrerer verschiedener experimenteller Zustände zu untersuchen. Neben einem gründlichen Methodenvergleich sollte die klinische Anwendbarkeit der indikatorgestützten EIT-Perfusionsmessung untersucht werden, indem wir vor allem die minimale Indikatorkonzentration analysierten, die eine robuste Perfusionsschätzung erlaubte und den geringsten Einfluss für den Patienten darstellt. Neben den experimentellen Validierungsstudien wurden zwei in-silico-Untersuchungen durchgeführt, um erstens die Sensitivität von EIT gegenüber des Durchgangs eines leitfähigen Indikators durch die Lunge vor stark heterogenem pulmonalen Hintergrund zu bewerten. Zweitens untersuchten wir die physiologischen Einflüsse, die zu den rekonstruierten EITPerfusionsbildern beitragen, um die Limitationen der Methode besser zu verstehen. Die Analysen zeigten, dass die Schätzung der Lungenperfusion auf der Basis der indikatorverstärkten EIT ein großes Potenzial für die Anwendung in der klinischen Praxis aufweist, da wir sie mit zwei Goldstandard-Perfusionsmesstechniken validieren konnten. Zudem konnten wertvolle Schlüsse über die physiologischen Einflüsse auf die geschätzten EIT Perfusionsverteilungen gezogen werden

New insights on COPD imaging via CT and MRI

Multidetector-row computed tomography (MDCT) can be used to quantify morphological features and investigate structure/function relationship in COPD. This approach allows a phenotypical definition of COPD patients, and might improve our understanding of disease pathogenesis and suggest new therapeutical options. In recent years, magnetic resonance imaging (MRI) has also become potentially suitable for the assessment of ventilation, perfusion and respiratory mechanics. This review focuses on the established clinical applications of CT, and novel CT and MRI techniques, which may prove valuable in evaluating the structural and functional damage in COPD