Multi-level tuberculosis of the spine identified by 18 F-FDG-PET/CT and concomitant urogenital tuberculosis: a case report from the spinal TB X cohort.

BACKGROUND: Tuberculosis (TB) is caused by Mycobacterium tuberculosis (Mtb) and typically infects the lungs. However, extrapulmonary forms of TB can be found in approximately 20% of cases. It is suggested, that up to 10% of extrapulmonary TB affects the musculoskeletal system, in which spinal elements (spinal tuberculosis, STB) are involved in approximately 50% of the cases. STB is a debilitating disease with nonspecific symptoms and diagnosis is often delayed for months to years. In our Spinal TB X Cohort, we aim to describe the clinical phenotype of STB using whole-body 18 F-fluorodeoxyglucose positron emission tomography computed tomography (PET/CT) and to identify a specific gene expression profile for the different stages of dissemination on PET/CT. Here we report on the first patient recruited into our cohort who underwent PET/CT before treatment initiation, at 6-months and at 12-months - time of TB treatment completion. CASE PRESENTATION: A 27-year-old immunocompetent male presented with severe thoracolumbar back pain for 9 months with severe antalgic gait and night sweats. Magnetic resonance imaging (MRI) of the whole spine revealed multilevel spinal disease (T5/6, T11/12, L3/4) in keeping with STB. After informed consent and recruitment into the Spinal TB X Cohort, the patient underwent PET/CT as per protocol, which revealed isolated multilevel STB (T4-7, T11/12, L3/4) with no concomitant lung or urogenital lesion. However, sputum and urine were Xpert MTB/RIF Ultra positive and Mtb was cultured from the urine sample. CT-guided biopsy of the T11/12 lesion confirmed drug-sensitive Mtb on Xpert MTB/RIF Ultra and the patient was started on TB treatment according to local guidelines for 12 months. The 6-month follow-up PET/CT revealed new and existing spinal lesions with increased FDG-uptake despite significant improvement of clinical features and laboratory markers. After 9 months of treatment, the patient developed an acute urethral stricture, most likely due to urogenital TB, and a suprapubic catheter was inserted. The 12-month PET/CT showed significantly decreased PET/CT values of all lesions, however, significant persistent spinal inflammation was present at the end of TB treatment. Clinically, the patient was considered cured by the TB control program and currently awaits urethroplasty. CONCLUSIONS: In our case, PET/CT emerged as a valuable imaging modality for the initial assessment, surpassing MRI by revealing more comprehensive extensive disease. Subsequent PET/CT scans at 6-month uncovered new lesions and increased inflammation in existing ones, while by the end of TB treatment, all lesions exhibited improvement. However, the interpretation of FDG avidity remains ambiguous, whether it correlates with active infection and viable Mtb. or fibro- and osteoblast activity indicative of the healing process. Additionally, the absence of extraspinal TB lesions on PET/CT despite positive microbiology from sputum and urine maybe explained by paucibacillary, subclinical infection of extraspinal organs. The Spinal TB X Cohort endeavours to shed light on whole-body imaging patterns at diagnosis, their evolution midway through TB treatment, and upon treatment completion. Ultimately, this study aims to advance our understanding of the biology of this complex disease.

Comparing gene expression profiles of adults with isolated spinal tuberculosis to disseminated spinal tuberculosis identified by 18FDG-PET/CT at time of diagnosis, 6- and 12-months follow-up: classifying clinical stages of spinal tuberculosis and monitoring treatment response (Spinal TB X cohort study).

BACKGROUND: Tuberculosis (TB) is one of the top ten causes of death worldwide, with approximately 10 million cases annually. Focus has been on pulmonary TB, while extrapulmonary TB (EPTB) has received little attention. Diagnosis of EPTB remains challenging due to the invasive procedures required for sample collection. Spinal TB (STB) accounts for 10% of EPTB and often leads to lifelong debilitating disease due to devastating spinal deformation and compression of neural structures. Little is known about the extent of disease, although both isolated STB and a disseminated form of STB have been described. In our Spinal TB X cohort study, we aim to describe the clinical phenotype of STB using whole-body 18FDG-PET/CT, identify a specific gene expression profile for different stages of dissemination and compare findings to previously described gene expression signatures for latent and active pulmonary TB. METHODS: A single-centre, prospective cohort study will be established to describe the distributional pattern of STB detected by whole-body 18FDG-PET/CT and gene expression profile of patients with suspected STB on magnetic resonance imaging (MRI) at point of diagnosis, six months, and 12 months. Blood biobanking will be performed at these time points. Specimens for microbiology will be obtained from sputum/urine, from easily accessible sites of disease (e.g., lymph nodes, abscess) identified in the first 18FDG-PET/CT, from CT-guided biopsy and/or surgery. Clinical parameters and functional scores will be collected at every physical visit. Data will be entered into RedCap® database; data cleaning, validation and analysis will be performed by the study team. The University of Cape Town Ethics Committee approved the protocol (243/2022). DISCUSSION: The Spinal TB X cohort study is the first prospective cohort study using whole-body 18FDG-PET/CT scans in patients with microbiologically confirmed spinal tuberculosis. Dual imaging techniques of the spine using 18FDG-PET/CT and magnetic resonance imaging as well as tissue diagnosis (microbiology and histopathology) will allow us to develop a virtual biopsy model. If successful, a distinct gene-expression profile will aid in blood-based diagnosis (point of care testing) as well as treatment monitoring and would lead to earlier diagnosis of this devastating disease. TRIAL REGISTRATION: The study has been registered on ClinicalTrials.gov (NCT05610098).

To treat or not to treat tuberculosis -clinical decision making in patients with previous pulmonary tuberculosis using 18F-FDG PET/CT.

Post-tuberculosis (TB) radiological changes and symptoms can mimic TB. PCR-based diagnostic tests can show positive results, suggesting the presence of Mycobacterium tuberculosis DNA in the absence of viable bacteria. We present a case with two episodes of previous TB. Despite workup including trace to low positive PCR results, after performing sputum analysis, bronchoalveolar lavage analysis, cyto-brush and 18F-FDG PET/CT guided transthoracic biopsy, no culturable mycobacteria were detected. 18F-FDG PET/CT showed a high metabolic activity of the biopsied lesions. More accurate strategies and tools in patients with previous TB and positive PCR results are required to make appropriate treatment decisions.

High resolution imaging and five-year tuberculosis contact outcomes.

Background: The evolution of tuberculosis (TB) disease during the clinical latency period remains incompletely understood. Methods: 250 HIV-uninfected, adult household contacts of rifampicin-resistant TB with a negative symptom screen underwent baseline 18F-Fluorodeoxyglucose positron emission and computed tomography (PET/CT), repeated in 112 after 5-15 months. Following South African and WHO guidelines, participants did not receive preventive therapy. All participants had intensive baseline screening with spontaneous, followed by induced, sputum sampling and were then observed for an average of 4.7 years for culture-positive disease. Baseline PET/CT abnormalities were evaluated in relation to culture-positive disease. Results: At baseline, 59 (23.6%) participants had lung PET/CT findings consistent with TB of which 29 (11.6%) were defined as Subclinical TB, and 30 (12%) Subclinical TB-inactive. A further 83 (33.2%) had other lung parenchymal abnormalities and 108 (43.2%) had normal lungs. Over 1107-person years of follow-up 14 cases of culture-positive TB were diagnosed. Six cases were detected by intensive baseline screening, all would have been missed by the South African symptom-based screening strategy and only one detected by a WHO-recommended chest X-Ray screening strategy. Those with baseline Subclinical TB lesions on PET/CT were significantly more likely to be diagnosed with culture-positive TB over the study period, compared to those with normal lung parenchyma (10/29 [34.5%] vs 2/108 [1.9%], Hazard Ratio 22.37 [4.89-102.47, p<0.001]). Conclusions: These findings challenge the latent/active TB paradigm demonstrating that subclinical disease exists up to 4 years prior to microbiological detection and/or symptom onset. There are important implications for screening and management of TB.

HIV status and survival of patients with pulmonary hypertension due to left heart disease: the Pan African Pulmonary Hypertension Cohort.

In sub-Saharan Africa, little is known about pulmonary hypertension in left heart disease (PH-LHD). We used multivariate logistic and cox-hazard proportional regression models to examine factors associated with increased right ventricular systolic pressure (RVSP) and the effect of real-world HIV status scenarios on 6-month survival rate in the Pan African Pulmonary Hypertension Cohort (PAPUCO) study, a prospective cohort from four African countries. Exposure to biomass fuel smoke (aOR, 95%CI 3.07, 1.02-9.28), moderate to severe NYHA/FC III/IV (aOR, 95%CI 4.18, 1.01-17.38), and unknown HIV status (aOR, 95%CI 2.73, 0.96-7.73) predicted moderate to severe RVSP at the time of presentation. Six months later, HIV infection, moderate-to-severe NYHA/FC, and alcohol consumption were associated with decreased survival probabilities. Upon adjusting for HIV infection, it was observed that an incremental rise in RVSP (1 mmHg) and inter-ventricular septal thickness (1 mm) resulted in an 8% (aHR, 95%CI 1.08, 1.02-1.13) and 20% (aHR, 95%CI 1.2, 1.00-1.43) increase in the probability of mortality due to PH-LHD. In contrast, the risk of death from PH-LHD was reduced by 23% for each additional unit of BMI. (aHR, 95%CI 0.77, 0.59-1.00). In conclusion, the present study offers insights into the determinants that are notably linked to unfavorable survival outcomes in patients with pulmonary hypertension due to left heart disease. Certain factors identified in this study are readily evaluable and amenable to modification, even in settings with limited resources.

Long-Term Follow-up of Human Immunodeficiency Virus-Associated Pulmonary Hypertension: Clinical Features and Survival Outcomes of the Pan Africa Pulmonary Hypertension Cohort (PAPUCO).

Background: Data characterizing risk factors and long-term outcome studies on human immunodeficiency virus (HIV)-associated pulmonary hypertension (PH) in Africa are lacking. Methods: The Pan African Pulmonary Hypertension Cohort, a multinational registry of 254 consecutive patients diagnosed with PH (97% of African descent) from 9 centers in 4 African countries was implemented. We compared baseline characteristics and 3-year survival of an HIV-infected cohort newly diagnosed with PH (PH/HIV+) to an HIV-uninfected cohort with PH (PH/HIV-). Results: One hundred thirty-four participants with PH completed follow up (47 PH/HIV+ and 87 PH/HIV-; age median, 36 versus 44 years; P = .0004). Cardiovascular risk factors and comorbidities were similar except for previous tuberculosis (62% versus 18%, P < .0001). Six-minute walk distance (6MWD) <300 meters was common in PH/HIV- (P = .0030), but PH/HIV+ had higher heart (P = .0160) and respiratory (P = .0374) rates. Thirty-six percent of PH/HIV+ and 15% of PH/HIV- presented with pulmonary arterial hypertension (PAH) (P = .0084), whereas 36% of PH/HIV+ and 72% of PH/HIV- exhibited PH due to left heart disease (PHLHD) (P = .0009). Pulmonary hypertension due to lung diseases and hypoxia (PHLD) was frequent in PH/HIV+ (36% versus 15%) but did not reach statistical significance. Human immunodeficiency virus-associated PAH tended to have a poorer survival rate compared with PHLHD/PHLD in HIV-infected patients. Conclusions: The PH/HIV + patients were younger and commonly had previous tuberculosis compared to PH/HIV- patients. Despite a better 6MWD at presentation, they had more signs and symptoms of early onset heart failure and a worse survival rate. Early echocardiography assessment should be performed in HIV-infected patients with history of tuberculosis who present with signs and symptoms of heart failure or posttuberculosis lung disease.