Potential false positive antigranulocyte antibody scan

Potential false positive antigranulocyte antibody scan in a case of knee joint replacement within 12 months of surgery: 

Potential false positive antigranulocyte antibody scan in a case of knee joint replacement within 12 months of surgery MURALI Dept of Nuclear Medicine AUCKLAND CITY HOSPTIAL

PowerPoint Presentation: 

A 60 yr old female patient History of Right TKJR (Cemented) in March 2011 Subsequent Admission - Night sweat - Shortness of breath - Weight loss - Cellulitis

PowerPoint Presentation: 

RT KNEE Increasing pain and swelling INVESTIGATIONS Nil cause for symptoms CTPA ECHO Adrenal MRI Advised Antigranulocyte antibody scan To check for - infection or - other bone pathology BLOOD TESTS

Studies Performed: 

Studies Performed Two phase Bone Scan ( 99mTc-MDP ) of knees Blood pool and 3 hrs delayed Antigranulocyte Antibody scan (99mTc-Besilesomab) Whole Body SPECT/CT of Abdomen Bone Marrow Scan (99mTc-sulphur -Colloid) of Knees 30 minute Post injection 4 HR & 24 HR

Two phase bone scan (99m Tc-MDP , 400 MBq) : 

Two phase bone scan ( 99m Tc-MDP , 400 MBq ) Increased Blood pool activity and uptake at 3 hours ( arrows ) 3 HOUR BLOOD POOL R R R

PowerPoint Presentation: 

Besilesomab (Scintimun®) is a Murine immunoglobulin of IgG1 isotype that specifically binds to NCA-95 , an Epitope expressed at the cell membrane of Granulocytes as well as in Granulopoietic Bone Marrrow cells. CIS BIO International

Antigranulocyte antibody scan 99m Tc “Scintimun” 715 MBq : 

Antigranulocyte antibody scan 99m Tc “Scintimun” 715 MBq ANT 4 HR POST4 HR ANT 24 HR POST 24 HR R R (Arrow) Slightly increased uptake of tracer around the Right TKR Could indicate either: Infection Bone marrow stimulation by the recent surgery L L

Antigranulocyte antibody scan SPECT/CT (approx 3mSV) ABDOMEN SEPSIS ? CAUSE : 

Antigranulocyte antibody scan SPECT/CT (approx 3mSV) ABDOMEN SEPSIS ? CAUSE 4 HR 24 HR NO FOCAL UPTAKE IN ABDOMEN

BONE SCAN AND AGA SCAN: 

BONE SCAN AND AGA SCAN ANTIGRANULOCYTE AB scan BONE SCAN TO DISTINGUISH BETWEEN INFECTION AND BONE MARRROW STIMULATION

BONE MARROW SCAN 99m Tc Sulphur Colloid 300 MBq : 

BONE MARROW SCAN 99m Tc Sulphur Colloid 300 MBq R R A (Arrow) Increased uptake of tracer around the Right TKR Indicates Bone Marrow stimulation by the recent surgery

COMPARISION: 

COMPARISION BONE SCAN ANTIGRANULOCYTE AB scan BONE MARROW SCAN ALMOST SIMILAR SCAN APPEARANCES

PowerPoint Presentation: 

Bone marrow stimulation by surgery is the reason for increased uptake of antigranulocyte antibody in the TKJR region. Bone marrow scan may help reduce false positives, if antigranulocyte antibody scintigraphy is performed on prosthetic joints within 12 months of surgery. Conclusion: Anti granulocyte WBC is good scan to evaluate the presence of infection – TKJR/other replacements less than 12 months old.

PowerPoint Presentation: 

Thanks to my Department Doctors and Colleagues

Follow up: 

Follow up Patient referred to pain clinic and Physiotherapy On Medicines Amitriptyline Clonidine (Transdermal Patch) Paracetamol Tramadol hypochloride

Suggested Reading: 

Suggested Reading Besilesomab for imaging inflammationand infection in peripheral bone in adultswith suspected osteomyelitis www.dovepress.com Adriana Blazeski Kenneth M Kozloff Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA; 2Orthopaedic Research Laboratories, Department of Orthopedic Surgery, 3Department of Radiology, University of Michigan Medical School, Ann Arbor, MI, USA

PowerPoint Presentation: 

99mTc Besilesomab Scintigram SPECT CT SENSITIVITY SPECIFICITY 89 % 73 % 18F - FDG Comparison between 99mTc-Scintimun, 99mTc-HMPAO-WBC and 18F-FDG in hip prostheses infection. D. Familiari 1 , , P. Pizzichini 3 , M. Pacilio 1 , R. Boni 2 , F. Trapasso 3 , A. Signore 1 ; Conclusion : In this series of patients AG scan with Scintimun seems to be highly accurate and could replace WBC scan for imaging hip-prosthesis with associated infection. WBC scan is however to be considered as the gold standard. FDG scan cannot always distinguish between sterile inflammation and infection . CT for both SPECT and PET, is relevant to increase diagnostic accuracy.