Infection Imaging In Nuclear Medicine: Arguing The Case for PET/CT.

Transcription

1 Infection Imaging In Nuclear Medicine: Arguing The Case for PET/CT. LUIS A. TAMARA M.D. NUCLEAR MEDICINE /PET-CT SERVICE CHIEF MEDVAMC

2 DISCLOSURES. 2

3 3

4 Not difficult to appreciate the difference! GA-67 CITRATE / LABELED LEUKOCYTES FDG PET-CT 4

5 So what exactly do you mean? GA-67 / WBC S. FDG PET CT o Use of blood products. o Results available in days. o Relatively low sensitivity and spatial resolution. No blood products required. Results available in a couple of hours. All imaging advantages of PET /CT 5

6 Fever of Unknown Origin/ Bacteremia of Unknown Source. Low specificity of FDG an advantage. Greater than 90% accuracy. Helpful clinically even when negative. Whole Body scanning routine. Keidar et al. 6

7 Spinal cord injury patient with persistent fever despite broad, prolonged antimicrobial Rx. 7

8 Persistent MSSA bacteremia despite adequate treatment of septic joints. 8

9 Pt with fever and bacteremia. 9

10 61 y. o. male with polymicrobial bacteremia of unknown source Patent rt. PV Lt. PV Thrombus Patent rt. PV Lt. PV Thrombosis 10

11 61 y. o. male with polymicrobial bacteremia of unknown source 11

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13 Pt with persistent bacteremia of unknown source 13

14 Post contrast enhancement Enhancement 14

15 Acute Osteomyelitis In a lesion-based analysis FDG PET/CT was TP in 18 sites, TN in 26 sites and FP in 2 sites, resulting in a sensitivity, specificity, PPV, NPV and accuracy of 100%, 93%,90 %, 100 % and 96 %, respectively. o Kagna et al. Able to differentiate from neuroarthropathic changes in the diabetic foot. o Basu et al. 15

16 Pt with bilateral LE cellulitis. 16

17 Pt with suspected calcaneal osteomyelitis 17

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19 Pt evaluated for diabetic foot 19

20 71 y. o. male on HD with MRSA bacteremia and suspected right hallux osteomyelitis. 20

21 Same Patient FDG NaF 21

22 Chronic Osteomyelitis The overall accuracy of FDG PET was 97% with a high degree of inter-observer concordance (x = 0.93). The overall sensitivity and specificity were 100% and 92%, respectively. Guhlman et al. Very high NPV for vertebral osteomyelitis. In certain cases of smoldering chronic osteomyelitis FDG + NaF A little more on that later 22

23 Vertebral Osteomyelitis 23

24 Vertebral Osteomyelitis Post Rx 24

25 Spinal Cord injury patient with decubitus ulcer NaF-FDG 25

26 SCI patient with decubitus ulcer NaF- FDG 26

27 Pt with diabetic heel ulcer NaF-FDG 27

28 Endocarditis and endovascular infections The validity values for the efficacy of PET/CT in the diagnosis of septic lesions were as follows: sensitivity, 100%; specificity, 80%; positive predictive value, 90%; and negative predictive value, 100%. PET/CT was the only initially positive imaging technique in 15 true-positive cases (55.5%). The systematic use of PET/CT was associated with a 2-fold reduction in the number of relapses (9.6% vs. 4.2%, P ) and enabled significantly more infectious complications to be diagnosed (18% vs. 57.4%, P ). Kestler et al. 28

29 69 y. o. male with hx of endocarditis 29

30 Post Rx. 30

31 Vascular Graft Infections PET/CT had a sensitivity of 93%, specificity of 91%,positive predictive value of 88%, and negative predictive value of 96% for the diagnosis of vascular graft infection. Keidar et al. Some caveats: Gore Tex (polytetrafluoroethylene) and Dacron. Aseptic inflammation. Wassellius et al. 31

32 59 y. o. male s/p open heart surgery who presents with MSSA bacteremia. 32

33 Same patient 33

34 Post Rx. 34

35 Non Infectious FDG uptake 35

36 Labeled Leukocytes. 36

37 65 y. o. male s/p BLE bypass graft and persistent MRSA bacteremia. 37

38 The Infected Prosthesis Very high Negative Predictive Value. Specificity not as high due to osteolysis with loosening as well as infection. Non infectious FDG adhesion. In-111-WBC/SC Marrow imaging usually our first choice. 38

39 Infected and non-infected arthroplasties. 39

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41 Pt s/p comminuted distal femoral fracture and suspected infection. 41

42 Post Rx. 42

43 Pt s/p excisional biopsy of lymph node. Dx= Lymphoma. 43

44 Pt returns later and is febrile. Lymphoma recurrence? 44

45 Patient with recent spinal hardware placement and rising inflammatory markers. Infection is suspected.

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47 SCI patient with unexplained leukocytosis. 47

48 CONCLUSIONS PET/ CT is a fast, accurate, sensitive and specific diagnostic modality for the majority of infectious indications. It is superior to other NM modalities. It is cost effective. It improves patient care and patient outcomes. Broader CMS coverage would be in the best interest of both patients and managing clinicians. 48

49 The highest goal of knowledge is service. Kirpal Singh 49

50 REFERENCES 1. Keidar Z et al. Fever of Unknown Origin: The Role of F18-FDG PET/CT, J Nucl Med 2008; 49: Kagna O et al. FDG PET/CT imaging in the diagnosis of osteomyelitis in the diabetic foot, Eur J Nucl Med Mol Imaging (2012) 39: Basu S et al. Potential role of FDG PET in the setting of diabetic neuroosteoarthropathy: can it differentiate uncomplicated Charcot s neuroarthropathy from osteomyelitis and soft-tissue infection? Nuclear Medicine Communications 2007, 28: Guhlman A et al. Chronic Osteomyelitis: Detection with FDG PET and Correlation with Histopathologic Findings. Radiology #{149} March 1998.

51 REFERENCES 5. Kestler M et al. Role of 18F-FDG PET in Patients with Infectious Endocarditis, J Nucl Med 2014; 55: Keidar Z et al. Prosthetic Vascular Graft Infection: The Role of 18F-FDG PET/CT, J Nucl Med 2007; 48: Wasselius J et al. High 18F-FDG Uptake in Synthetic Aortic Vascular Grafts on PET/CT in Symptomatic and Asymptomatic Patients, J Nucl Med 2008; 49:

52 CME QUESTIONS 1. In the setting of FUO, PET CT results can be available in a matter of: a. Seconds. b. Minutes. c. Hours. (Key) d. Days. ours Reference 1. 52

53 2. According to the study quoted in the presentation, FDG PET CT for acute osteomyelitis had a sensitivity of: a. 80 % b. 100 % (key). c. 50 % d. 25 % Reference 2 53

54 3. The Negative Predictive Value (NPV) of FDG PET CT for vertebral osteomyelitis is: a. Very high (key). b. Very low. c. Unknown. d. Irrelevant. Reference 4. 54

55 4. According to the study quoted in the presentation, use of FDG PET CT in the setting of endocarditis was associated with a fold reduction in relapse rates. a. 3. b. 5 c. 2 (key). d. 6 Reference 5 55

56 5. The frequent, low level, diffuse FDG uptake seen in Gore- Tex synthetic vascular grafts is generally considered to reflect: a. Graft failure. b. Graft infection. c. Aseptic inflammation (key). d. Graft thrombosis. Reference 6 56