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.

Comparison of myocardial perfusion during hemodialysis and hemodiafiltration.

BACKGROUND: We compared myocardial perfusion in patients first on conventional hemodialysis (HD) and then on hemodiafiltration (HDF). METHODS: Myocardial perfusion scintigraphy was performed in 25 patients pre- and post-HD. Patients were then converted to HDF for 3 months prior to repeating the scintigraphy. (99m)Tc-methoxyisobutylisonitrile was administered intravenously pre-dialysis and then within the last hour of dialysis. Up to 90 min after injection, tomographic images were obtained. Clinical and laboratory data were collected pre- and post-dialysis. RESULTS: Five patients did not complete the study. Patients entering the study were on average 41.7 years old and on HD for 4 years (median). The mean standard Kt/V for the two procedures was not statistically different (1.55 for HD and 1.48 for HDF). The mean substitution volume for HDF was 18.48 liters. There were no significant differences in changes in blood pressures between HD and HDF (p = 0.22). There were no significant differences in myocardial perfusion defects in patients on HD compared with those on HDF. During dialysis in both studies, the data showed a general trend to worsening of perfusion defects. CONCLUSIONS: There was no advantage of HDF over HD with no statistical difference in perfusion defects between HD and HDF. There was a trend to worsening of perfusion defects during dialysis in the majority on HD and HDF. Midweek dialysis perfusion scores appeared to be consistently lower than early-week dialysis, but this was not statistically significant. The pathogenesis of the defects may lie at a microcirculatory level.

Tuberculous Spondylodiscitis with Psoas Abscess Descending into the Anterior Femoral Compartment Identified Using 2-deoxy-2-[18F]fluoroglucose Positron Emission Tomography Computed Tomography.

A 24-year-old immunocompetent woman underwent whole-body 18F-FDG PET/CT for the evaluation of MRI-suspicious tuberculous spinal lesions. The PET/CT results showed no pathological uptake in either lung, and there were no pathological changes on CT. There was increased uptake in the right psoas muscle, extending continuously down anterior to the right hip joint, posterior to and around the trochanteric region of the right femur, and into the right thigh, with an SUVmaxbw of 17.0. Subsequently, the patient underwent CT-guided biopsy as per protocol, which revealed drug-sensitive Mycobacterium tuberculosis, and the patient was started on standard tuberculosis treatment for 12 months.

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).

The conclusions drawn from ventilation/perfusion single-photon emission computed tomography compared with lung perfusion single-photon emission computed tomography and chest radiography in patients with suspected pulmonary thromboembolism.

PURPOSE: There are conflicting results from studies on whether ventilation scintigraphy can be safely omitted or replaced by chest radiography. These studies were based on planar ventilation/perfusion (V/Q) scintigraphy. We evaluated the value of the ventilation single-photon emission computed tomography (SPECT) on the final conclusion drawn from a V/Q SPECT and the possible role of the chest radiography as a surrogate for the ventilation SPECT. PATIENTS AND METHODS: Raw data of V/Q SPECT images and chest radiography acquired within 48 h over an 18-month period were retrieved, reprocessed and reviewed in batches. The ventilation SPECT, perfusion SPECT and chest radiography were reviewed separately and in combination. Data on the presence and nature of defects and chest radiography abnormalities were recorded. The V/Q SPECT images were interpreted using the criteria in the EANM guideline and the perfusion SPECT and chest radiography images were interpreted using the PISAPED criteria. Agreement between the diagnosis on the V/Q SPECT review and the perfusion SPECT and chest radiography review was analysed. RESULTS: Overall, 21.1% of the patients were classified as 'PE present' on the V/Q SPECT review, whereas 48.9% were classified as 'PE present' on the perfusion SPECT and chest radiography review. Only 5.4% of defects observed on ventilation SPECT had matched chest radiography lung field opacity. CONCLUSION: Our study showed that the omission of a ventilation SPECT led to a high rate of false-positive diagnoses and that the ventilation scan cannot be replaced by a chest radiography.

False-positive prostate cancer bone metastases on magnetic resonance imaging correctly classified on gallium-68-prostate-specific membrane antigen positron emission tomography computed tomography.

Imaging in prostate cancer is important in defining the local extent of disease, nodal involvement, and identifying metastases. Bone scan is the most commonly used modality for identification of bone metastasis in prostate cancer despite its reported low sensitivity and specificity compared to magnetic resonance imaging (MRI) which is the imaging gold standard for bone metastasis. Gallium-68 prostate-specific membrane antigen positron emission tomography-computed tomography (68Ga PSMA PET-CT) imaging is a relatively new addition to the imaging modalities in prostate cancer. This is a report of a patient with high-risk prostate cancer with features consistent with skeletal metastases on MRI but negative for skeletal metastases on bone scan and 68Ga PSMA PET CT. Histology confirmed the absence of skeletal metastases.

Source of Ectopic ACTH Secretion Easily Identified by 68 Ga DOTANOC PET/CT.

Malignant tumors account for most sources of ectopic ACTH Cushing syndrome (EA-CS). Early localization of the source and complete removal can be curative and also prevent metastasis. Diagnostic CT is known to perform better than PET/CT (low dose) in characterizing lung pathologies. However, bronchial carcinoids, a common source of EA-CS, may be difficult to detect on chest CT scan especially when it is small and located close to the hilar region. We present a case of EA-CS due to bronchial carcinoid, which was easily seen on Ga DOTANOC PET/CT after a diagnostic chest CT was reported as normal.

Metastatic papillary carcinoma of the thyroid in a patient previously treated for Graves' disease.

Incidental papillary carcinoma of the thyroid in patients treated surgically for benign thyroid diseases including Graves' disease is a known phenomenon. However, the management of these patients remains an issue of concern and controversy for those who care for them. We report a case of metastatic papillary carcinoma of the thyroid in a patient previously treated for Graves' disease. The subject of this presentation is a 50-year-old lady who was diagnosed with Graves' disease at the age of 29, for which she had a subtotal thyroidectomy following failure of medical and radioactive iodine treatment. Three years later, the patient was referred to our nuclear medicine department with a clinical diagnosis of suspected metastatic lymph nodes presumably from a thyroid malignancy.She had an 123I diagnostic whole body scan that showed 123I avid areas in the thyroid bed as well as left cervical lymph nodes, which later turned out to be metastatic papillary carcinoma of the thyroid on histology. She was treated with therapeutic doses of 131I. Follow-up radioactive iodine scans and serum thyroglobulin assays showed no evidence of malignant thyroid tissue. The occurrence of papillary carcinoma of the thyroid after a subtotal thyroidectomy for Graves' disease is hereby reported. The need for vigilance and regular follow-up in patients who receive all forms of treatment for benign thyroid diseases is emphasized.

Negative-pressure wound therapy II: negative-pressure wound therapy and increased perfusion. Just an illusion?

BACKGROUND: A recent study demonstrated that negative-pressure wound therapy increases underlying tissue pressure. This finding is incongruous with studies using laser Doppler that show that perfusion is immediately increased on initiation of suction. This study investigated perfusion in negative-pressure wound therapy using two alternative modalities. METHODS: Radioisotope perfusion imaging was used to determine perfusion beneath circumferential negative-pressure wound therapy dressings on 20 healthy hands (n = 20). Ten hands received suction pressures of -400 mmHg and 10 received -125 mmHg, with the contralateral hand used as a control without any suction. Transcutaneous partial pressure of oxygen was used to determine perfusion beneath noncircumferential negative-pressure wound therapy dressings on 12 healthy legs (n = 12), with each volunteer being sequentially randomized to receive suction pressures of -400 and -125 mmHg, respectively. RESULTS: Tissues undergoing circumferential negative-pressure wound therapy demonstrated a mean reduction in perfusion of 40 +/- 11.5 percent (p < 0.0005) and 17 +/- 8.9 percent (p < 0.0005) at suction pressures of -400 mmHg and -125 mmHg, respectively. Perfusion reduction at -400 mmHg was significantly greater than at -125 mmHg (p < 0.015). In the noncircumferential negative-pressure wound therapy group, there was a mean reduction in transcutaneous partial pressure of oxygen of 7.35 +/- 7.4 mmHg (p < 0.0005) and 5.10 +/- 7.4 mmHg (p < 0.0005) at suction pressures of -400 mmHg and -125 mmHg, respectively. There was a tendency for greater reductions in the -400 mmHg group, but this was not significantly different from the -125 mmHg group (p = 0.07). CONCLUSIONS: These findings demonstrate that perfusion beneath negative-pressure wound therapy decreases for increasing suction pressure. Thus, it is suggested that negative-pressure wound therapy should be used with caution on tissues with compromised vascularity, particularly when used circumferentially.