Exhaled Mycobacterium tuberculosis output and detection of subclinical disease by face-mask sampling: prospective observational studies.

BACKGROUND: Tuberculosis remains a global health challenge, with early diagnosis key to its reduction. Face-mask sampling detects exhaled Mycobacterium tuberculosis. We aimed to investigate bacillary output from patients with pulmonary tuberculosis and to assess the potential of face-mask sampling as a diagnostic method in active case-finding. METHODS: We did a 24-h longitudinal study in patients from three hospitals in Pretoria, South Africa, with microbiologically confirmed pulmonary tuberculosis. Patients underwent 1 h of face-mask sampling eight times over a 24-h period, with contemporaneous sputum sampling. M tuberculosis was detected by quantitative PCR. We also did an active case-finding pilot study in inhabitants of an informal settlement near Pretoria. We enrolled individuals with symptoms of tuberculosis on the WHO screening questionnaire. Participants provided sputum and face-mask samples that were tested with the molecular assay Xpert MTB/RIF Ultra. Sputum-negative and face-mask-positive individuals were followed up prospectively for 20 weeks by bronchoscopy, PET-CT, and further sputum analysis to validate the diagnosis. FINDINGS: Between Sept 22, 2015, and Dec 3, 2015, 78 patients with pulmonary tuberculosis were screened for the longitudinal study, of whom 24 completed the study (20 had HIV co-infection). M tuberculosis was detected in 166 (86%) of 192 face-mask samples and 38 (21%) of 184 assessable sputum samples obtained over a 24-h period. Exhaled M tuberculosis output showed no diurnal pattern and did not associate with cough frequency, sputum bacillary content, or chest radiographic disease severity. On May 16, 2018, 45 individuals were screened for the prospective active case-finding pilot study, of whom 20 had tuberculosis symptoms and were willing to take part. Eight participants were diagnosed prospectively with pulmonary tuberculosis, of whom six were exclusively face-mask positive at screening. Four of these participants (three of whom were HIV-positive) had normal findings on chest radiography but had treatment-responsive early tuberculosis-compatible lesions on PET-CT scans, with Xpert-positive sputum samples after 6 weeks. INTERPRETATION: Face-mask sampling offers a highly efficient and non-invasive method for detecting exhaled M tuberculosis, informing the presence of active infection both with greater consistency and at an earlier disease stage than with sputum samples. The approach shows potential for diagnosis and screening, particularly in difficult-to-reach communities. FUNDING: Wellcome Trust, CARA (Council for At-Risk Academics), University of Leicester, the UK Medical Research Council, and the National Institute for Health Research. VIDEO ABSTRACT.

The Current State of Artificial Intelligence in Medical Imaging and Nuclear Medicine.

The last decade has seen a huge surge in interest surrounding artificial intelligence (AI). AI has been around since the 1950s, although technological limitations in the early days meant performance was initially inferior compared to humans.1 With rapid progression of algorithm design, growth of vast digital datasets and development of powerful computing power, AI now has the capability to outperform humans. Consequently, the integration of AI into the modern world is skyrocketing. This review article will give an overview of the use of AI in the modern world and discuss current and potential uses in healthcare, with a particular focus on its applications and likely impact in medical imaging. We will discuss the consequences and challenges of AI integration into healthcare.

Delineating outcomes of patients with diffuse large b cell lymphoma using the national comprehensive cancer network-international prognostic index and positron emission tomography-defined remission status; a population-based analysis.

The recently devised National Comprehensive Cancer Network International Prognostic Index (NCCN-IPI) appears superior to the revised IPI (R-IPI) in delineating outcome in diffuse large B-cell lymphoma. We examined the outcome of a population-based cohort of 223 consecutive patients treated with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisolone) or R-CHOP-like immuno-chemotherapy between January 2005 and December 2011 by both the NCCN-IPI and R-IPI, and further stratified outcome by the achievement of both computerized tomography (CT) and positron emission tomography (PET)-CT complete remission (CR), with the latter reassessed using blinded central review by an independent nuclear medicine and radiology specialist. The NCCN-IPI was superior to the R-IPI in identifying patients at very high risk of systemic and/or central nervous system relapse. Notably, both the NCCN-IPI and the R-IPI remained strongly predictive of relapse irrespective of CT or PET-defined remission status following R-CHOP. Patients with high-risk NCCN-IPI scores (≥6) have a dismal outcome following R-CHOP therapy regardless of PET-defined response to R-CHOP. Moreover, such patients appear refractory to salvage chemotherapy and thus require alternative therapeutic approaches, although age and performance status may, for many patients, preclude the safe delivery of a primary intensified regimen. By contrast, patients with NCCN-IPI 1-5 who achieve PET-CR following R-CHOP have excellent outcomes and may merit reduced follow up frequency.

The role of single-photon emission computed tomography/computed tomography in localizing parathyroid adenoma.

With hybrid imaging playing an increasingly important role in nuclear medicine, this article reviews the literature on single-photon emission computed tomography/computed tomography (SPECT/CT) in parathyroid scintigraphy. An understanding of parathyroid and neck anatomy is important for accurate reporting of these scans, as this can have an impact on the surgical approach used. The contribution of SPECT/CT over and above SPECT alone is greatest in terms of localization, particularly for ectopic tumours. There remains controversy on the role of SPECT/CT in eutopic tumours, especially when considering such factors as imaging time and the additional radiation dose.

A United Kingdom based survey of clinical practice in the diagnosis of suspected pulmonary embolism.

OBJECTIVE: To identify UK practice in the diagnosis of suspected pulmonary embolism with particular reference to the pregnant population and to determine whether the 2003 British Thoracic Society (BTS) guidelines had influenced practice. METHOD: A postal survey was performed of all 249 nuclear medicine departments in the UK identified from the British Nuclear Medicine Society database. RESULTS: One hundred and one responses were received (41%). Ninety-eight centres (97%) performed scintigraphy with 17 using perfusion only imaging. A median of six (range: 1-27) scintigraphic scans were performed weekly. Ninety-seven centres had computed tomography (CT) capabilities although 11 centres only had single slice CT capability. A median of seven (range: 1-50) CT pulmonary angiographies (CTPAs) were performed weekly. Seventy-two centres used a diagnostic algorithm; 73 centres performed D-dimers routinely and 86 used probability criteria for reporting ventilation/perfusion (V/Q) scans. CTPA was performed in the majority of the cases with an abnormal chest radiograph. In pregnancy, 37 centres routinely performed D-dimers, 80 centres performed a scintigraphic based investigation as a first line test while 12 preferred CTPA. Of the 33 centres (34%) that indicated that the BTS guidelines had changed their practice, 30 (91%) commented that the demand for CTPA had increased and 29 (88%) felt that the service had been improved. CONCLUSION: There continues to be widely varying practice throughout the UK despite the BTS guidelines. There is a shift in practice towards CTPA and variation in the approach to diagnosis in pregnancy. The survey highlights the need to standardize the diagnostic algorithm for suspected pulmonary embolism, especially in pregnancy.

Brown adipose tissue and seasonal variation in humans.

OBJECTIVE: Brown adipose tissue (BAT) is present in adult humans where it may be important in the prevention of obesity, although the main factors regulating its abundance are not well established. BAT demonstrates seasonal variation relating to ambient temperature and photoperiod in mammals. The objective of our study was therefore to determine whether seasonal variation in BAT activity in humans was more closely related to the prevailing photoperiod or temperature. RESEARCH DESIGN AND METHODS: We studied 3,614 consecutive patients who underwent positron emission tomography followed by computed tomography scans. The presence and location of BAT depots were documented and correlated with monthly changes in photoperiod and ambient temperature. RESULTS: BAT activity was demonstrated in 167 (4.6%) scans. BAT was demonstrated in 52/724 scans (7.2%) in winter compared with 27/1,067 (2.5%) in summer months (P < 0.00001, chi(2) test). Monthly changes in the occurrence of BAT were more closely related to differences in photoperiod (r(2) = 0.876) rather than ambient temperature (r(2) = 0.696). Individuals with serial scans also demonstrated strong seasonal variation in BAT activity (average standardized uptake value [SUV(max)] 1.5 in July and 9.4 in January). BAT was also more common in female patients (female: n = 107, 7.2%; male: n = 60, 2.8%; P < 0.00001, chi(2) test). CONCLUSIONS: Our study demonstrates a very strong seasonal variation in the presence of BAT. This effect is more closely associated with photoperiod than ambient temperature, suggesting a previously undescribed mechanism for mediating BAT function in humans that could now potentially be recruited for the prevention or reversal of obesity.

Multimodality imaging of a retrosternal parathyroid adenoma with multiple brown tumors.

Brown tumors of hyperparathyroidism are rare but can mimic metastatic disease on many imaging modalities. We report the case of a patient presenting with symptomatic brown tumors of hyperparathyroidism due to a large retrosternal parathyroid adenoma, with histopathological correlation of both. The initial imaging findings on plain radiography, computed tomography, and bone scintigraphy were nonspecific and difficult to differentiate from the more common diagnosis of metastatic disease. Whole body sestamibi imaging however demonstrated increased uptake within both the mediastinal mass and multiple bone lesions leading to the correct diagnosis. We demonstrate modern multimodality imaging of this rare but treatable condition, and discuss the relevant literature.

Mobile PET in the UK: legislative, regulatory and cost-effectiveness considerations.

Mobile PET/CT or mobile stand alone PET, is becoming more widely available throughout the developed world, allowing many small and medium-sized hospitals that do not have the scale or financial resources to purchase the static diagnostic equipment, to benefit from this imaging technology. Before embarking on such a service, a number of legislative, logistical and administrative issues have to be addressed to ensure that a mobile PET/CT service is run with optimal efficiency and safety and in compliance with the regulations governing the use of radioactive substances. Some of these issues are similar to those encountered in operating a mobile magnetic resonance imaging scanner but there are important differences owing to the use of both sealed and open radioactive sources. This article highlights the legislative, administrative and practical issues relevant to the UK and also discusses some of the practical issues that need to be addressed to ensure the operation of a safe and effective PET service.