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Contrary to traditional teaching, patients with Primary Spontaneous Pneumothorax (PSP) do not have normal lungs. Emphysema-like change (ELC) and inflammation are common. However, the natural history of ELC and its significance in terms of future disease is not known. Current management of pneumothorax is generic and not personalised. This thesis updates the UK epidemiology of pneumothorax, describes the use of two novel methods to examine the lungs, a method of predicting early treatment failure, the association of CT findings and recurrence, and a systematic review of chemical pleurodesis to reduce recurrence. Analysis of fifty years' data on ~150,000 admissions demonstrated that the incidence of pneumothorax is increasing, and established a method to identify primary from secondary pneumothoraces and their relative risk of recurrence. Reduced ventilation of hyperpolarised Xenon on enhanced-Magnetic Resonance Imaging (MRI) was seen in those PSP patients with greater low attenuation areas on Computed Tomography (CT) and with reduced pulmonary function. A model of lung inhomogeneity found that metrics of lung ventilation distinguished pneumothorax patients from healthy volunteers and Chronic Obstructive Pulmonary Disease (COPD) patients. This may represent subtle or mild disease, not identified on standard testing, which may be exacerbated by smoking. CT scanning found that mild emphysema and cystic airspaces were common in PSP patients. Ex- or current smokers had more (and larger) cysts. Emphysema was more common in smokers and patients with a history of previous pneumothorax: who were at higher risk of recurrence. However, variation in number and size of cysts were seen in both those patients with and without recurrence. As such, no single algorithm to predict recurrence was identified. Airflow measurement early in the patient pathway has the potential to identify those likely to fail treatment, potentially allowing early triage to surgery. The addition of talc or minocycline as an adjunct to surgery provides the lowest recurrence rates, but physician-led talc poudrage may be similarly effective. Those in whom surgery is not suitable, chemical pleurodesis could be offered via chest drain. Data presented in this thesis thus provides insights into the underlying abnormalities in PSP and lays the groundwork for strategies to fundamentally alter the management paradigm.

Traumatic injury is a major burden in global healthcare systems, ranking among the leading causes of morbidity and mortality worldwide.1 Patients are first encountered at the pre-hospital scene by providers of varying levels of expertise, such as emergency medical technicians (EMTs) and paramedics, who provide temporizing measures while patients are transported to receiving hospitals to receive definitive care.2 Ultrasound is an ever-improving medical imaging modality which is increasingly portable, low cost, and provides diagnostic imaging rapidly without the harmful effects of radiation. The objective of this study is to determine whether introduction of prehospital ultrasound (PHUS) for use on ground ambulances by prehospital providers in order to improve choice of destination hospital and aid in needle thoracostomy for tension pneumothorax will have a positive impact on mortality rate of trauma patients in an urban EMS environment. In the proposed study, trauma patients in the city of Boston, Massachusetts receiving care from Boston Emergency Medical Services (EMS) prehospital providers will be recruited over a 12-month period with a minimum goal of 2,500 patients in total. Emergency responses coded as trauma by EMS dispatch will be randomized at a 1:1 ratio to either utilize PHUS or to refrain from utilizing PHUS. A z-test will be used to analyze primary outcome of 30-day mortality rate in patients who receive PHUS care as needed compared with patients who do not receive PHUS care. Study data will be collected directly from Boston EMS Electronic Medical Record (EMR). This study will be the first of its kind to randomize at the patient level, and the first to investigate a major clinical outcome of ultrasound in prehospital medical care: 30-day mortality. Point-of-care Ultrasound is an intriguing diagnostic modality that is becoming increasingly feasible in the prehospital environment, and may improve outcomes in trauma patients. Current studies provide convincing evidence for the diagnostic accuracy of these devices, especially in evaluating hemoperitoneum and pneumothorax. If an improvement in mortality rate of patients treated with prehospital ultrasound (PHUS) is demonstrated, this will be convincing evidence for the implementation of PHUS in ground ambulances and air medical services across the United States and worldwide.

Background:The optimal approach for management of spontaneous pneumothoraces (SPs) and the safety of air travel in patients with pulmonary Langerhans cell histiocytosis (PLCH) are not well established. Methods:Patients with PLCH were recruited from the Rare Lung Diseases Clinic Network and the Histiocytosis Association, and surveyed about disease manifestations and safety of air travel.Results:A total of 94 patients completed the survey. Median age at diagnosis of PLCH was 40 years (range: 15-67 years). Average interval between symptom onset and diagnosis was 2.9 years (range: -4 to 31 years). Twenty-two patients (23%) had at least one SP, of which 14 (64%) had at least one additional SP that showed either an ipsilateral recurrence (10 patients; 45%) or a contralateral recurrence (8 patients; 36%). Mean age at the time of first SP was 29 years. SP was the presenting manifestation that led to the diagnosis of PLCH in 19% of patients, typically after the second episode. Surgical pleurodesis reduced the recurrence rate of SP by half in comparison with conservative management (29% vs. 65%, p = 0.025). Two patients experienced an episode of SP during air travel, consistent with an air travel-related pneumothorax rate of 2.4% per patient and 0.27% per flight.Conclusions:SP is a common manifestation of PLCH, can be seen in approximately one-fourth of the patients, and has a high recurrence risk. Surgical pleurodesis leads to a substantial reduction in the SP recurrence risk. The risk of an air travel-related SP in patients with PLCH is about 2-3 per thousand flights.

Phase Stretch Transform (PST) is a physics-inspired computational approach developed in Jalali lab for feature enhancement in images. Here, it is applied to medical images. The results of its application to X-rays leads to development of an assistance tool for diagnosis of pneumothorax in X-ray images. The tool, which is first-of-its-kind, helps in locating the boundary of a collapsed lung, a life-critical clinical examination which is otherwise difficult for a radiologist to locate with a naked eye. Additionally, PST is applied to other medical images, such as histology and mammograms, to demonstrate feature enhancement. The resulting edge detection map offers promising application in segmentation and analysis of medical images which is explored here. Further, texture segmentation using PST is also demonstrated.