Use of fluorine-18 fluoro-2-deoxy-D-glucose positron emission tomography in assessing the process of tuberculous spondylitis

Spine Infections: the role of Fluorodeoxyglucose Positron Emission Tomography (FDG PET) in the context of the actual diagnosis guideline

Spondylodiscitis is an infectious process that requires numerous health care professionals to be clearly diagnosed and eventually successfully treated. It implies a variety of microbiological agents and conditions; during the diagnostic workup, it is difficult to correctly identify them, and the clinician has to rapidly choose the correct treatment to avoid permanent injuries to the patient. In this context, we conducted a review to better understand the most suitable use of Positron Emission Tomography with 18-Fluoro-deossi-glucose (FDG PET) in a patient suspected of spondylodiscitis, based on current guidelines and literature.. We wanted to review the role of FDG PET in the spondylodiscitis diagnosis and follow up in the context of the current guidelines.

Biomarkers to predict FDG PET/CT activity after the standard duration of treatment for spinal tuberculosis: An exploratory study

OBJECTIVES

18F-Fluorodeoxyglucose (FDG) Positron Emission Tomography- Computed Tomography (PET/CT) scans can be used to assess healing following treatment for spinal tuberculosis (TB) but have limited accessibility and high cost. This study investigated the association between immune biomarkers and FDG-PET/CT activity after ≥9 months of treatment for spinal TB.

METHODS

Patients who had completed ≥9 months of treatment for spinal TB were recruited from a major hospital in the Western Cape, South Africa. Participants underwent a FDG-PET/CT scan and FDG- PET/CT activity was quantified for all spinal and extra-spinal sites. Participants also provided a blood sample, which was evaluated for 19 cytokines along with erythrocyte sedimentation rate (ESR). Correlations and multiple regression analyses were used to investigate the association between biomarkers and PET/CT measures.

RESULTS

Twenty-eight patients were recruited, of whom 24 (86%) had spinal and/or extra-spinal FDG-PET/CT activity. In the strongest multiple regression model, CXCL10/IP-10, VEGFA, IFN-γ, CRP and Factor D/Adipsin explained 52% of the variation in overall maximal FDG uptake. Conventional monitoring marker ESR showed no significant association with PET/CT measures.

CONCLUSIONS

The current findings offered encouragement that biomarkers to predict FDG-PET/CT activity may show some promise and identified candidate biomarkers for further investigation in this regard.

Joint EANM/ESNR and ESCMID-endorsed consensus document for the diagnosis of spine infection (spondylodiscitis) in adults

PURPOSE

Diagnosis of spondylodiscitis (SD) may be challenging due to the nonspecific clinical and laboratory findings and the need to perform various diagnostic tests including serologic, imaging, and microbiological examinations. Homogeneous management of SD diagnosis through international, multidisciplinary guidance would improve the sensitivity of diagnosis and lead to better patient outcome.

METHODS

An expert specialist team, comprising nuclear medicine physicians appointed by the European Association of Nuclear Medicine (EANM), neuroradiologists appointed by the European Society of Neuroradiology (ESNR), and infectious diseases specialists appointed by the European Society of Clinical Microbiology and Infectious Diseases (ESCMID), reviewed the literature from January 2006 to December 2015 and proposed 20 consensus statements in answer to clinical questions regarding SD diagnosis. The statements were graded by level of evidence level according to the 2011 Oxford Centre for Evidence-based Medicine criteria and included in this consensus document for the diagnosis of SD in adults. The consensus statements are the result of literature review according to PICO (P:population/patients, I:intervention/indicator, C:comparator/control, O:outcome) criteria. Evidence-based recommendations on the management of adult patients with SD, with particular attention to radiologic and nuclear medicine diagnosis, were proposed after a systematic review of the literature in the areas of nuclear medicine, radiology, infectious diseases, and microbiology.

RESULTS

A diagnostic flow chart was developed based on the 20 consensus statements, scored by level of evidence according to the Oxford Centre for Evidence-based Medicine criteria.

CONCLUSIONS

This consensus document was developed with a final diagnostic flow chart for SD diagnosis as an aid for professionals in many fields, especially nuclear medicine physicians, radiologists, and orthopaedic and infectious diseases specialists.

Prospective comparison of whole-body (18)F-FDG PET/CT and MRI of the spine in the diagnosis of haematogenous spondylodiscitis

PURPOSE

To prospectively compare (18)F-FDG PET/CT and MRI in the diagnosis of haematogenous spondylodiscitis

METHODS

The study included 26 patients (12 women, 14 men; mean age 59 ± 17 years) with clinical symptoms of infection of the spine. Patients who had had prior spinal surgery or any type of antibiotic therapy in the previous 3 months were excluded from the study. Whole-body PET/CT 60 min after injection of 4.07 MBq/kg of (18)F-FDG and an MRI scan of the spine was performed in all patients. SUVmax in an area surrounding the lesions with the suspicion of infection as well as a background SUVmean in a preserved area of the spine were calculated for quantification. Infection was diagnosed by microbiological documentation in cultures of image-guided spinal puncture fluid or blood. Infection was excluded if symptoms were absent without antimicrobial therapy during a follow-up of at least 6 months.

RESULTS

Spondylodiscitis was confirmed in 18 of the 26 patients. Staphylococcus aureus was found in 8 patients, Mycobacterium tuberculosis in 4, Escherichia coli in 2 and other pathogens in 4. Of the remaining 8 patients, the diagnoses were degenerative spondyloarthropathy in 5 and vertebral fracture in 3. The sensitivity, specificity, and positive and negative predictive value were 83%, 88%, 94% and 70% for (18)F-FDG PET/CT, and 94%, 38%, 77% and 75% for MRI, respectively. The accuracies of (18)F-FDG PET/CT and MRI were similar (84% and 81%, respectively). The combination of (18)F-FDG PET/CT and MRI detected the infection in 100% of the patients with spondylodiscitis. (18)F-FDG uptake, quantified in terms of SUVmax corrected by the background SUVmean, was significantly higher in patients with spondylodiscitis than in those without infection (p < 0.001).

CONCLUSION

Due to its high specificity, (18)F-FDG PET/CT should be considered as a first-line imaging procedure in the diagnosis of spondylodiscitis. Quantification of uptake in terms of SUVmax was able to discriminate infection of the spine from other processes in this series of patients.

Imaging findings of Pott's disease

Tuberculosis (TB) continues to be an important public health problem in developed countries especially in deprived socioeconomic groups, older people, immunocompromised patients, drug-therapy resistant cases and the immigrant population. The spine is the most frequent location of musculoskeletal TB. The wide range of clinical presentations results in difficulties and delays in diagnosis. Advanced disease mimics other infections and malignancy. The diagnosis of spinal infections relies on three main factors: clinical symptoms, imaging and bacteriological culture. Advanced imaging such as Magnetic Resonance Imaging (MRI), Multidetector Computed Tomography (MDCT) and Fluor18-Deoxiglucose Positron Emission Tomography combined with CT (F-18 FDG PET-CT) demonstrate lesion extent, serve as guide for biopsy with aspiration for culture, assist surgery planning and contribute to follow-up. Diagnosis of TB cannot be established solely on the basis of clinical tests or imaging findings and biopsy may be required. Differential diagnosis between tuberculous and pyogenic spondylitis is of clinical importance, but may be difficult on the basis of radiological findings alone. Findings not pathognomonic but favoring tuberculous etiology include: slow progression of lesions with late preservation of disk space, involvement of several contiguous segments, large intraosseous and paraspinal abscesses containing calcifications, and body collapse with kyphotic deformity. In this essay the highlights of TB imaging are reviewed through published literature. In addition, we review retrospectively the radiological findings of 48 patients with tuberculous spondylitis treated from 1993 to 2010. There were 23 male and 25 female patients with a mean age of 53 years.

Fluorine-18 fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography scan contributes to the diagnosis and management of brucellar spondylodiskitis

Background

Limited data suggest that fluorine-18 fluoro-2-deoxy-D-glucose (F-18 FDG) positron emission tomography combined with computed tomography (PET/CT) scan may be useful for diagnosing infections of the spine. Brucellar spondylodiskitis might be devastating and current imaging techniques lack sensitivity and specificity. The aim of this prospective study was to determine the role of F-18 FDG PET/CT scan in the diagnosis of brucellar spondylodiskitis and in monitoring the efficacy of its treatment.

Methods

Ten consecutive patients with brucellar spondylitis were prospectively evaluated with PET/CT. Baseline evaluation included also magnetic resonance imaging (MRI) of the affected spine, indices of inflammation, the slide agglutination test (SAT), and the standard hematology and biochemistry. All cases were treated with suitable antibiotics until resolution or significant improvement of clinical and radiological (MRI) findings. Upon completion of treatment, they were re-evaluated with follow-up PET/CT scan. The maximum standardized uptake values (SUV) were measured and compared with SAT.

Results

In all patients there was an increased F-18 FDG activity in the infected spine region detected by the initial MRI. F-18 FDG PET/CT provided additional information, compared to MRI, in 4 (40%) patients. More specifically it revealed additional spine lesions (in 3 patients), lymphadenitis, arthritis, organomegaly, as well as new paravertebral soft tissue involvement and epidural masses. This additional information had an impact on the duration of treatment in these patients. At the end of treatment all patients had a complete clinical response; 5 patients had positive serology, 6 patients had residual MRI findings, while 9 had a positive PET/CT but with significantly decreased FDG uptake compared to baseline (median 2.6, range 1.4 – 4.4 vs. median 5.5, range 2.8 – 9.4, p = 0.005). During the follow up period (median 12.5 months) no relapses have been observed. No significant association was observed between the SUV and SAT.

Conclusions

Our study suggests that in patients with brucellar spondylodiskitis F-18 FDG PET/CT scan can provide additional information on the spread of the infection, compared to MRI. Successful treatment is associated with a significant decrease in SUVmax values; thus, PET/CT scan may be a complementary method for determining the efficacy of treatment.

Efficacy of extended DOTS category I chemotherapy in spinal tuberculosis based on MRI-based healed status

BACKGROUND

Duration of treatment in tuberculosis of spine has always been debatable in the absence of marker of healing. The objective of the study was to evaluate the efficacy of extended DOTS regimen (2 months of intensive phase and 6 months of continuation phase) as recommended by WHO, by using MRI observations as the healing marker.

MATERIALS AND METHODS

51 (Group A -28 prospective and Group B- 23 retrospective) patients of spine TB with mean age of 26.8 years (range 15-54 years) diagnosed clinico radiologically/imaging (n=36), histopathology or by PCR (n=15) were enrolled for the study. They were treated by extended DOTS regimen (2 months of HRZE and 6 months of HR) administered alternate day. The serial blood investigations and X-rays were done every 2 months. Contrast MRI was done at the end of 8 months and healing changes were recorded. Criteria of healing on the basis of MRI being: complete resolution of pre and paravertebral collections, resolution of marrow edema of vertebral body (VB), replacement of marrow edema by fat or by calcification suggested by iso- intense T1 and T2 weighted images in contrast enhanced MRI. Patients with non healed status, but, responding lesion on MRI after 8 months of treatment were continued on INH and rifampicin alternate day and contrast MRI was done subsequently at 12 months and 18 months till the healed status was achieved .

RESULTS

9 patients had paraplegia and required surgical intervention out of which 1 did not recover neurologically. All patients have completed 8 months of extended DOTS regimen, n=18 achieved healed status and duration of treatment was extended in rest (n=33) 5 were declared healed after 12 months, 8 after 18 months and one after 36 months of treatment, thus 32 were declared healed at varying periods.

CONCLUSION

35.2% patients demonstrate MRI based healed vertebral lesion at the end of 8 months of extended category 1 DOTS regimen. It is unscientific to stop the ATT by fixed time frame and MRI evaluation of the patients is required after 8 months of ATT and subsequently to decide for the continuation stoppage of treatment.

Abnormal FDG uptake on 18F-fluorodeoxyglucose positron emission tomography in patients with cancer diagnosis: case reports of tuberculous lymphadenitis

Although 18F-FDG-PET is very sensitive for a variety of malignancies, it can lack specificity. In addition to malignant tissue, any active infectious or inflammatory process can demonstrate FDG avidity. We report 3 patients with different types of cancer who had abnormal 18F-FDG uptake on PET scan caused by tuberculous lymphadenitis. All were found to have incidental multiple lymph adenopathies with increased FDG uptake on PET scan. All three patients were proved to have tuberculosis lymphadenitis by pathologic examination and were successfully treated with anti-tuberculous therapy.

Scintigraphic imaging of vertebral osteomyelitis with 111in-biotin

STUDY DESIGN

Early diagnosis of vertebral infection (hematogenous or postsurgical) is necessary to choose a correct therapy and to minimize dramatic complications. All patients suspected to have vertebral infection underwent radiologic imaging and In-Biotin scintigraphy.

OBJECTIVE

Biotin is a growth factor used by many bacteria. The aim of our study is to use In-Biotin to diagnose vertebral infections.

SUMMARY OF BACKGROUND DATA

Magnetic resonance imaging, even if endowed with fairly good sensitivity and specificity, shows some limitations in the study of the onset of pathology and in postsurgical conditions. Conventional scintigraphic imaging, like bone scintigraphy with Tc-MDP, Ga-citrate scintigraphy, or Positron Emission Tomography with [F]FDG, are limited by relatively low specificity; the use of Streptavidin/In-Biotin scintigraphy, based on aspecific uptake of tracer in the site of infection, shows good results in term of sensibility and specificity but the use of heterologous protein might engender immunogenic reactions.

METHODS

All patients (pts) (n = 110) of the study underwent In-biotin scintigraphy 2 hours after intravenous injection of the tracer, 71 pts were suspected to have hematogenous vertebral infection (Group I) and 39 pts were suspected to have postsurgical infection (Group II). The reference for final diagnosis was either bacterial cultures, histopathologic analysis, and/or clinical/imaging follow-up for at least 1 year.

RESULTS

In-biotin scintigraphy showed a sensitivity of 84% and specificity of 98% in Group I and a sensitivity of 100% and specificity of 84% in Group II.

CONCLUSION

Our results showed that In-Biotin scintigraphy possess high diagnostic accuracy. This technique is easy to perform and requires short imaging time-point after intravenous tracer injection. Moreover if In-Biotin uptake is due only to high proliferation rate of bacteria presents in site of infection, it will be further investigated to discriminate definitely bacterial from sterile inflammation.

Osteomyelitis

Bone and joint infections are painful for patients and frustrating for both them and their doctors. The high success rates of antimicrobial therapy in most infectious diseases have not yet been achieved in bone and joint infections owing to the physiological and anatomical characteristics of bone. The key to successful management is early diagnosis, including bone sampling for microbiological and pathological examination to allow targeted and long-lasting antimicrobial therapy. The various types of osteomyelitis require differing medical and surgical therapeutic strategies. These types include, in order of decreasing frequency: osteomyelitis secondary to a contiguous focus of infection (after trauma, surgery, or insertion of a joint prosthesis); that secondary to vascular insufficiency (in diabetic foot infections); or that of haematogenous origin. Chronic osteomyelitis is associated with avascular necrosis of bone and formation of sequestrum (dead bone), and surgical debridement is necessary for cure in addition to antibiotic therapy. By contrast, acute osteomyelitis can respond to antibiotics alone. Generally, a multidisciplinary approach is required for success, involving expertise in orthopaedic surgery, infectious diseases, and plastic surgery, as well as vascular surgery, particularly for complex cases with soft-tissue loss.

Multifocal Pott's disease (tuberculous spondylitis) incidentally detected on Tc-99m MDP bone and Ga-67 citrate scintigraphy in a patient with diabetes

Pott's disease is an uncommon extrapulmonary form of tuberculosis. Delay in diagnosis and management may cause serious complications. The authors describe Pott's disease incidentally detected on Tc-99m MDP bone and Ga-67 imaging in a patient with diabetes. Tc-99m MDP bone scintigraphy showed intensely increased uptake in the lower cervical spine and lumbosacral regions. Ga-67 scintigraphy revealed intensely increased uptake corresponding to the areas noted on Tc-99m MDP bone scintigraphy. Magnetic resonance imaging showed destructive lesions in the C5-C6 and L5-S1 intervertebral discs with destruction of adjacent end plates. Biopsy of the lumbosacral area was guided by computed tomography, and histologic examination of the bone specimen showed caseation, giant cells, and acid-fast bacilli. Posterior decompression and posterolateral spinal fusion with bone grafts were performed. Antituberculous chemotherapy with isoniazid, rifampicin, pyrazinamide, and ethambutol was started. The patient showed remarkable relief of symptoms during a period of 9 months of therapy. Both Tc-99m MDP bone and Ga-67 imaging can offer the convenience of screening the entire body to detect multiple sites of Pott's disease.

Positron emission tomography imaging in nonmalignant thoracic disorders

The role of the fluorodeoxyglucose (FDG) technique positron emission tomography (PET) is well established in the management of patients with lung cancer. Increasingly, it is becoming evident that FDG-PET can be effectively employed to diagnose a variety of benign pulmonary disorders. Knowledge of such applications further expands the domain of this powerful modality and further improves the ability to differentiate benign from malignant diseases of the chest. We describe pertinent technical factors that substantially contribute to optimal imaging of the thoracic structures. Particularly, the complementary role of attenuation correction (AC) to that of non-AC images is emphasized. We further outline the need for and the state of the art for co-registration of PET and anatomic images for diagnostic and therapeutic purposes. We then review patterns of physiologic uptake of FDG in thoracic structures, including the lung, the heart, the aorta and large arteries, esophagus, thymus, trachea, thoracic muscles, bone marrow, and joints and alterations following radiation therapy to the thorax. A great deal of information is provided with regard to differentiating benign from malignant nodules and in particular, we emphasize the role of dual time point imaging and partial volume correction for accurate assessment of such lesions. Following a brief review of the diagnostic issues related to the assessment of mediastinal adenopathies, the role of FDG-PET imaging in environment-induced lung diseases, including pneumoconiosis, smoking, and asthma are described. A large body of information is provided about the role of this technology in the management of patients with suspected infection and inflammation of the lungs such as acquired immunodeficiency syndrome, fever of unknown origin, sarcoidosis, chronic granulomatous disease and monitoring the disease process and response to therapy. Finally, the value of FDG-PET in differentiating benign from malignant diseases of the pleura including asbestosis-related disorders is described at the conclusion of this comprehensive review.

18-fluorodeoxyglucose positron emission tomographic imaging in the detection and monitoring of infection and inflammation

During the past decade, 18-fluorodeoxyglucose (FDG) positron emission tomography (PET) has rapidly evolved from a pure research modality to a clinical necessity. FDG-PET was introduced to determine the state of brain function in physiologic and pathologic states. Its use as a powerful tool to diagnose, stage, and monitor patients with a variety of malignancies has been truly revolutionary. However, FDG is a nonspecific tracer and it has been found to accumulate at sites of infection and inflammation. It is becoming evident that PET imaging will play a major role in the treatement of patients with suspected infection and inflammation. PET has been shown to be particularly valuable in the evaluation of chronic osteomyelitis, infected prostheses, sarcoidosis, fever of unknown origin, and acquired immunodeficiency syndrome. Because of its ability to quantitate the rate of FDG uptake, PET may prove to be a powerful modality for the monitoring of disease activity and response to therapy. Novel PET tracers are being tested for imaging infection and inflammation that may further enhance the role of this technique in the appropriate clinical setting. PET imaging to detect and characterize infection and inflammation may become a major clinical indication in the day-to-day practice of medicine.