|Year : 2022 | Volume
| Issue : 3 | Page : 295-296
99mTc-ethambutol scan with SPECT/CT in knee joint tuberculosis
Simran Kalra1, Nishikant Avinash Damle1, Piyush Ranjan2, Sunit Sikdar2, Geetanjali Arora1, Ankur Goyal3, Deepak Gautam4
1 Department of Nuclear Medicine and PET-CT, All India Institute of Medical Sciences, New Delhi, India
2 Department of Medicine, All India Institute of Medical Sciences, New Delhi, India
3 Department of Radiology, All India Institute of Medical Sciences, New Delhi, India
4 Department of Orthopedics, All India Institute of Medical Sciences, New Delhi, India
|Date of Submission||23-Jan-2022|
|Date of Decision||01-Mar-2022|
|Date of Acceptance||16-Mar-2022|
|Date of Web Publication||02-Nov-2022|
Dr. Nishikant Avinash Damle
Department of Nuclear Medicine and PET-CT, All India Institute of Medical Sciences, New Delhi - 110 029
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Modalities for in vivo imaging of Mycobacterium tuberculosis are limited and inadequately studied. One such modality is 99mTc-ethambutol scintigraphy which has shown promising results for diagnosis of tuberculosis (TB). Ethambutol, one of the primary antitubercular drugs, is bacteriostatic which acts on the mycolic acid cell wall synthesis of the M. tuberculosis. However, literature on its utility is scarce. The few studies that exist have reported its sensitivity and specificity between 90%– 95% and 71%–85%. We present here a case demonstrating the role of 99mTc-ethambutol scan in knee joint TB.
Keywords: 99mTc-Ethambutol, knee joint, tuberculosis
|How to cite this article:|
Kalra S, Damle NA, Ranjan P, Sikdar S, Arora G, Goyal A, Gautam D. 99mTc-ethambutol scan with SPECT/CT in knee joint tuberculosis. Indian J Nucl Med 2022;37:295-6
|How to cite this URL:|
Kalra S, Damle NA, Ranjan P, Sikdar S, Arora G, Goyal A, Gautam D. 99mTc-ethambutol scan with SPECT/CT in knee joint tuberculosis. Indian J Nucl Med [serial online] 2022 [cited 2022 Nov 29];37:295-6. Available from: https://www.ijnm.in/text.asp?2022/37/3/295/360259
Modalities for in vivo imaging of Mycobacterium tuberculosis e limited and inadequately studied. One such modality is 99mTc ethambutol scintigraphy which has shown promising results for diagnosis of tuberculosis (TB). Ethambutol, one of the primary antitubercular drugs, is bacteriostatic which acts on the mycolic acid cell wall synthesis of the M. tuberculosis. However, literature on its utility is scarce. The few studies that exist have reported its sensitivity and specificity between 90%– 95% and 71%–85%.,,,,, A 48-year-old female with no known comorbidities presented with pain, swelling, and restricted motion of the right knee joint for the past 4 years associated with weight loss and loss of appetite. CRP and ESR were toward higher side. She was treated on analgesics and empirical antibiotics and recommended physiotherapy, all to no avail. The pain gradually increased in intensity, and she was taken to a health facility where magnetic resonance imaging (MRI) was conducted. On MRI scan, a complicated cyst was seen over the lateral aspect of the right knee joint with lateral meniscus tear and degenerative changes. An arthroscopic debridement along with the excision of the cyst was done, and intra-articular viscous supplement was injected. The patient improved, but the symptoms reappeared after 2 months. The patient was referred to our institution where MRI was repeated, and based on radiological findings, diagnosis of knee joint skeletal tuberculosis (TB) was made. The patient was then referred to the nuclear medicine department for further evaluation with 99mTc-ethambutol scintigraphy. 99mTc-Ethambutol was synthesized in-house with radiochemical purity 95%. Dose of 10 mCi 99mTc-ethambutol was injected intravenously, and serial planar whole-body anterior and posterior images were acquired at 15–30-min intervals up to 2 h and at 4 h postinjection. Anterior whole-body image showed radiotracer accumulation in the gallbladder and urinary bladder, depicting normal routes of excretion. No significant (mild) thyroid or splenic uptake was seen, suggesting good radiolabeling. Both kidneys were visualized as shown in [Figure 1].
|Figure 1: Maximum intensity projection (a) image of PET revealed increased metabolic activity in the right knee joint. Sagittal T1-weighted (b) and T2-weighted (c) magnetic resonance images showing geographic areas of altered signal intensity in the lateral femoral and tibial condyles, bound by hypointense serpiginous lines, suggestive of epiphyseal bone infarcts. Effusion noted in suprapatellar recess. Coronal STIR (d) and postcontrast T1-weighted (e) images depicting joint effusion, synovial thickening, marked periarthritis, and soft-tissue inflammation consistent with active tuberculosis. Sagittal section of the right knee SPECT/CT (f) showing diffuse increased tracer uptake in the ends of tibia and femur and suprapatellar region. Coronal and axial CT images (g and i) and SPECT/CT (h and j) showing lytic sclerotic changes in the lower end of right femur and upper end of the right tibia with increased uptake|
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Based on our diagnosis of TB knee, the patient was put on anti-tubercular therapy (ATT) by the treating physician. After 3 months of ATT, the patient was symptomatically better and was able to perform her daily activities.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that her name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
This study was funded by ITR division ICMR New Delhi as source of funding.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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