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[Diagnosis of infection in surgery of the locomotor system with Tc-99m-HMPAO leukocyte scintigraphy]
Abstract
70 patients with confirmed (23 patients) or suspected (47 patients) bacterial infection in the skeleton following diseases, injuries or operations in orthopedic surgery were investigated using Tc-99m-HMPAO leucocyte scintigraphy in order to evaluate the accuracy of this procedure. Infections could be detected correctly in 37 of 70 patients (right positives) while 28 patients had negative scans corresponding to the clinical course (right negatives). One false negative finding was observed. Five patients with clinically suspected infection had a focal uptake in the WBC-scan and were not operated subsequently. They range as false positive results, although they belong to a special group (Infection: Yes-Operation: No [IYON]-group). In the assessment of the Tc-99m-HMPAO-WBC-scan there was a senstivity of 97.1%, specificity of 82.9% and an overall accuracy of 90%. The method is suitable for detection of early and late infection as well as chronic or hematogenous osteomyelitis in the locomotor system. This means an important contribution in diagnosis of infection determining further operative or conservative treatment.
... Esta técnica tiene una sensibilidad de 95% pero su especificidad es de 54%. [22][23][24] Punción. Si existen evidencias clínicas y radiologías de infección protésica la punción aspirativa para obtener líquido para cultivo es una ayuda valiosa en el apoyo diagnóstico. ...
INTRODUCCION Los reemplazos articulares de caderas enfer-mas alivian el sufrimiento y restauran la fun-ción de miles de personas año tras año. En E.U.A. se realizan 250.000 artroplastías de cadera anualmente. Sin embargo, como todo acto quirúrgico, no están exentas de complica-ciones siendo la infección periprotésica sin duda la más temida, tanto por los costos emocionales inherentes al largo proceso de tratamiento a se-guir, como por la implicancia económica que ésta tiene. El costo anual que representa el tra-tamiento de una artroplastía infectada en E.U.A. fue estimado en 1984 entre 40 y 80 millones de dólares. Actualmente se considera que un pa-Rev Chil Infect (2000); 17 (2): 92-100 INFECTOLOGIA AL DIA DIAGNOSIS AND TREATMENT OF HIP PROSTHESIS INFECTION The periprosthetic infection that occurs in about 1% of total hip arthroplasties, implies high emotional and economical cost for the patient and for health care systems, respectively. In this article the pathophysiology of this complication and the disposable diagnostic resources are reviewed. Two alternative treatments have been proposed: debridement with prosthesis retention or resection of the arthroplasty (in one or two times). Topical antibiotic benefits used for the prevention of prosthesis infection at total hip arthroplasty are refered.
... 20 General surgeons have found imaging with technetium-99m methylene diphosphonate-labeled leukocytes to be effective in the evaluation of abdominal abscesses. 21 Although some researchers have suggested that this imaging technique is applicable to the musculoskeletal system, 22 its use in the patient with a painful total hip arthroplasty has been disappointing. In a study of 29 patients who were treated surgically, I found this technique to be associated with an unacceptably high rate of false-positive images, especially in the evaluation of patients with a Girdlestone resection arthroplasty who were being evaluated for hip reconstruction with a two-stage technique. ...
Periprosthetic joint infection (PJI) in the hip following prosthetic joint placement is a devastating outcome of an otherwise often successful surgical treatment (total-hip arthroplasty). Management of PJI is dependent upon accurate diagnosis and successful treatment, both of which are challenging. Recently, great strides have been made in improving the diagnosis of PJI, which has no 'gold standard' diagnostic tool. Proper diagnosis is essential as untreated or undetected PJI can quickly lead to biofilm formation on the implant surface depending upon the infecting organism. Upon complete biofilm formation, successful treatment requires prosthetic resection with immediate or delayed reimplantation. Even with the most aggressive surgical treatment, PJI eradication currently has a success rate of approximately 80%. Unfortunately, technologies to improve the local delivery of antibiotics are not expected to be available in the near future.
... ) and 99mTc-HMPAO (1453 lesions)[62][63][64][65][66][67]. Both techniques allow a diagnostic accuracy of around 90%. ...
The inflammation and infection of bone include a wide range of processes that can result in a reduction of function or in the complete inability of patients. Apart from the inflammation, infection is sustained by pyogenic microorganisms and results mostly in massive destruction of bones and joints. The treatment of osteomyelitis requires long and expensive medical therapies and, sometimes, surgical resection for debridement of necrotic bone or to consolidate or substitute the compromised bones and joints. Radiographs and bone cultures are the mainstays for the diagnosis but often are useless in the diagnosis of activity or relapse of infection in the lengthy management of these patients. Imaging with radiopharmaceuticals, computed tomography and magnetic resonance are also used to study secondary and chronic infections and their diffusion to soft or deep tissues. The diagnosis is quite easy in acute osteomyelitis of long bones when the structure of bone is still intact. But most cases of osteomyelitis are subacute or chronic at the onset or become chronic during their evolution because of the frequent resistance to antibiotics. In chronic osteomyelitis the structure of bones is altered by fractures, surgical interventions and as a result of bone reabsorption produced by the infection. Metallic implants and prostheses produce artefacts both in computed tomography and magnetic resonance images, and radionuclide studies should be essential in these cases. Vertebral osteomyelitis is a specific entity that can be correctly diagnosed by computed tomography or magnetic resonance imaging at the onset of symptoms but only with radionuclide imaging is it possible to assess the activity of the disease after surgical stabilization or medical therapy. The lack of comparative studies showing the accuracy of each radiopharmaceutical for the study of bone infection does not allow the best nuclear medicine techniques to be chosen in an evidence-based manner. To this end we performed a meta-analysis of peer reviewed articles published between 1984 and 2004 describing the use of nuclear medicine imaging for the study of the most frequent causes of bone infections, including prosthetic joint, peripheric post-traumatic bone infections, vertebral and sternal infections. Guidelines for the choice of the optimal radiopharmaceuticals to be used in each clinical condition and for different aims is provided.
We report here the results of a validation study of the avidin/indium-111 biotin approach in patients with skeletal lesions.
This study involved 54 patients with orthopaedic conditions: 20 patients with intermediate suspected osteomyelitis of the
trunk, 19 patients with infection/inflammation of prosthetic joint replacements, and 15 patients with suspected osteomyelitis
of appendicular bones. Avidin (3mg) was injected as an i.v. bolus, followed 4h later by 111In-biotin; imaging was acquired 30min and 16–18h after administration of 111In-biotin. Technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO)-labelled leucocyte scintigraphy was performed in 39/54 patients. The overall sensitivity of the avidin/111In-biotin scan was 97.7% (versus 88.9% for 99mTc-HMPAO leucocyte scintigraphy). While the diagnostic performance of avidin/111In-biotin scintigraphy was similar to that of 99mTc-HMPAO leucocyte scintigraphy in patients with prosthetic joint replacements or osteomyelitis of appendicular bones, the
avidin/111In-biotin approach clearly performed better than 99mTc-HMPAO leucocyte scintigraphy in patients with suspected osteomyelitis of the trunk (100% sensitivity, specificity and accuracy
versus 50% sensitivity, 100% specificity and 66.7% accuracy for 99mTc-HMPAO-leucocyte scintigraphy). These results demonstrate the feasibility of the avidin/111In-biotin approach for imaging sites of infection/inflammation in the clinical setting. Although no systematic advantages
of avidin/111In-biotin scintigraphy were found versus 99mTc-HMPAO leucocyte scintigraphy, the newer scintigraphic method is more practicable and involves lower biological risk for
the operators.
In order to evaluate the importance of 99mTc-hexamethylpropylene amine oxime (99mTc-HMPAO) leukocyte scintigraphy in the diagnosis of bone infection, we retrospectively reviewed 324 patients. Abnormal findings were seen in 221 patients. In the other 103 cases acute pathological inflammation could be ruled out. The patients with pathological findings were divided into four groups according to the location of the infection. This method showed the localizations of skeletal disorders and its differences to other diagnostic imaging modalities. The underlying abnormalities causing the inflammation were determined. In conclusion, 99mTc-HMPAO leukocyte scintigraphy is still a very sensitive method for either whole body screening or local detection of acute or exacerbated chronic osteomyelitis. The advantages of this method over other diagnostic imaging methods are shown.
The aim of this study was to evaluate, retrospectively, the diagnostic value of Tc hexamethylpropylene amine oxime (99mTc-HMPAO) labelled autologous leucocytes for the preferred septic localizations of the infection of the endoprosthesis. We retrospectively reviewed 67 patients with implanted endoprostheses. Diagnosis was found in 42/67 patients. In 25/67 patients we were able to negate an acute pathological process of infection of the endoprosthesis. Our patients were divided into three groups according to the type of endoprosthesis (hip joint, knee joint, shoulder joint). The localizations of the endoprosthesis disorders are shown. The preferred localizations of the acute infection of the hip endoprosthesis are the regio intertrochanterica and the middle part of the shaft of the prosthesis. The preferred localization of the acute infection of the knee endoprosthesis is the proximal shaft of the tibia. The preferred localization of the acute infection of the shoulder endoprosthesis is the distal end of the prosthesis in the proximal humerus. It is hoped that the knowledge of these preferred localizations of infection of endoprosthesis will help patients and doctors in diagnosis and treatment in the future.
Streptavidin accumulates at sites of inflammation and infection as a result of increased capillary permeability. In addition to being utilised by bacteria for their own growth, biotin forms a stable, high-affinity non-covalent complex with avidin. The objective of this investigation was to determine the diagnostic performance of two-step streptavidin/111In-biotin imaging for evaluating patients with suspected vertebral osteomyelitis.
We evaluated 55 consecutive patients with suspected vertebral osteomyelitis (34 women and 21 men aged 27-86 years), within 2 weeks after the onset of clinical symptoms. Thirty-two of the patients underwent magnetic resonance imaging (MRI) and 24, computed tomography (CT). DTPA-conjugated biotin was radiolabelled by incubating 500 microg of DTPA-biotin with 111 MBq of 111In-chloride. Two-step scintigraphy was performed by first infusing 3 mg streptavidin intravenously, followed 4 h later by 111In-biotin. Imaging was begun 60 min later.
Streptavidin/111In-biotin scintigraphy was positive in 32/34 patients with spinal infection (94.12% sensitivity). The study was negative in 19/21 patients without infection (95.24% specificity). The corresponding results for MRI and CT were 54.17% and 35.29% (sensitivity), and 75% and 57.14% (specificity), respectively. All statistical parameters of diagnostic performance (Youden's J index, kappa measure of agreement with correct classification, accuracy, sensitivity, specificity, positive likelihood and negative likelihood) were clearly better for streptavidin/111In-biotin scintigraphy than for either MRI or CT.
Streptavidin/111In-biotin scintigraphy is highly sensitive and specific for detecting vertebral osteomyelitis in the first 2 weeks after the onset of clinical symptoms, and is potentially very useful for guiding clinical decisions on instituting appropriate therapy.
Bone infections represent a diagnostic or therapeutic challenge for the infectivologist, orthopaedic surgeon, radiologist and nuclear medicine physician. Staphylococcus aureus is the major bacterium responsible for bone infections although Mycobacterium tuberculosis is emerging as an infectious agent in Italy because of immigration from Africa and Asia. Osteomyelitis requires long and expensive antibiotic treatment, including rifampicin administered parenterally for several weeks and the use of antimicrobial-impregnated cement in prosthesis substitution. Sometimes it is necessary to carry out surgical debridement of a necrotic bone or the consolidation of compromised bones and joint prosthesis implants. Radiographs and bone cultures are mainstays for the diagnosis of bone infections but are often useless in the lengthy management of these patients. Diagnosis of skeletal infections still includes conventional radiography but magnetic resonance imaging is essential in haematogenous and spinal infections. Bone scans are still useful in acute osteomyelitis whereas scintigraphy using labelled white blood cells is preferred in infections of peripheral bone segments or joint prosthesis. In the axial skeleton a combination of an agent for detecting inflammation ((67)Ga citrate) and a metabolic agent ((99m)Tc-methylene diphosphonate) enables an infection and an area of increased metabolic activity to be distinguished. [(18)F]Fluorodeoxyglucose positron emission tomography, where available, has a significant impact in the study of infections using radionuclides: high-resolution tomographic images represent an effective alternative to gallium in the assessment of inflammation of spine lesions but a comparison with morphological examinations (computed tomography or magnetic resonance imaging) is essential.
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.
Biotin is a growth factor used by many bacteria. The aim of our study is to use In-Biotin to diagnose vertebral infections.
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.
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.
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.
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.
Hexamethylpropylene-amineoxime (HMPAO) forms a lipid-soluble neutral complex with 99mTc which is rapidly incorporated into leucocytes in vitro. In six patients with suspected or known inflammatory disease, a "mixed" leucocyte suspension isolated from 85 ml blood anticoagulated with acid-citrate-dextrose was labelled by 99mTc-HMPAO with a mean efficiency of 47% (SE2%), of which 78% (3) was taken up by granulocytes. Activity eluted more rapidly from other cell types in vitro than from granulocytes, which remained firmly labelled. Mean initial biodistribution of the label and granulocyte recovery in blood of 32% (8) at 30-40 min showed that the granulocytes were not significantly activated during labelling. All six patients were positive for inflammatory disease, as early as 30 min in five patients and at 3 h in the sixth; they all remained positive at 20-24 h. Four patients also received 111In-labelled "pure" granulocytes. In terms of detail, the 99mTc images were comparable or superior to the 111In images.
Twenty-four patients with a history of post-traumatic fracture nonunion underwent sequential 99mTc and 67Ga citrate scintigraphy in an attempt to differentiate between posttraumatic fracture nonunion and nonunion complicated by subclinical osteomyelitis. Neither technetium nor gallium studies alone nor in combination, with or without clinical correlation, could help delineate between fracture nonunion and nonunion complicated by subclinical osteomyelitis because of the increased technetium and gallium radioisotope uptake associated with the nonunion site.
We have evaluated the use of Gallium-67 scans as an aid to the diagnosis of infection around the hip joint after operation. We performed 12 gallium-67 scintiscans on six patients with diaphyseal fractures of the femur or tibia reduced by external fixation, and 65 scintiscans on 60 hips after operation, which included 22 Moore's prosthesis, 31 total replacements, three nail-plates and four revisions of total replacements. We also scanned the healing surgical wounds in a further 11 patients.
Simple fractures or osteotomies did not lead to abnormal uptake of 67Ga. Although some uptake in the scar was encountered the surgical wound did not complicate the interpretation of the scan. When assessing infection in the hip operations the rate of true-positive was 11/11, or 100%. The false-positive rate could not be assessed until after at least one year's follow-up. It was certainly less than 14% immediately after operation and less than 6% when the scan was performed three months after operation. Four patients were found to have a loose prosthesis but had a normal scintiscan, as had three patients presenting with post-operative pain.
It appears that 67Ga is clinically an efficient means for early detection of infection about the operated hip, and is useful in the differential diagnosis of a painful hip after surgery.