Subacute and chronic bone infections: diagnosis using In-111, Ga-67 and Tc-99m MDP bone scintigraphy, and radiography

The usefulness of indium-111 white blood cell scintigraphy in the diagnosis of subacute or chronic bone infection was examined in 21 orthopedic patients. In-111 WBC imaging was compared with gallium-67 and technetium-99m methylene diphosphonate skeletal scintigraphy and bone radiography, all studies being performed within 1 week. In-111 WBC scintigraphy showed no definite advantage over Ga-67 scintigraphy in the identification of chronic bone infection. The two tests had the same sensitivity (80%) and similar specificity (In-111 WBC 75%, Ga-67 83%; difference not significant). Bone radiography had a sensitivity of 60% and a specificity of 67%. A negative Tc-99m MDP bone scintigram ruled out infection (sensitivity 100%), but because of low specificity (25%), final evaluation required performance of Ga-67 or In-111 WBC scintigraphy.     

Sequential technetium-99m sulfur colloid/indium-111 white blood cell imaging in macroglobulinemia of Waldenstrom

Technetium-99m sulfur colloid (SC) and indium-111 labeled leukocyte (In-111 WBC) scintigraphy was performed on a 77-year-old female patient to rule out a left periprosthetic infection. Anterior Tc-99m SC and In-111 WBC images of the pelvis and femurs revealed no abnormal deposition of radiotracer about the Austin-Moore prosthesis. Absent radiotracer uptake, however, was demonstrated within the left hemipelvis. A left iliac bone marrow aspirate and biopsy revealed a lymphoplasmacytic infiltrate consistent with Waldenstrom's macroglobulinemia.     

Nonvisualization of sterile surgical incisions with indium-111 labeled leukocytes

The localization of In-111 labeled leukocytes (WBCs) in recent surgical incisions was studied in 18 patients. In-111 WBC images correlated well with culture results and clinical findings. No accumulation of In-111 WBCs was detected at the site of noninfected incisions in nine patients. In-111 WBCs did accumulate at incision sites in nine patients with infected surgical incisions. These results indicate that In-111 WBC study can accurately distinguish between normal healing and infection of recent surgical incisions.     

Complications of fractures and their healing

The role of nuclear medicine studies in diagnosing late complications of fractures is described. Static bone scintigraphy is not helpful in predicting delayed or non-union of fractures. Several investigators have developed simple formulae comparing uptake in fracture site with adjacent or contralateral normal bone and described criteria that will predict problems with healing. These types of tests should only be used in patients who are at risk for delayed union. The scintigraphic diagnosis of infection complicating a fracture is difficult. Bone scintigraphy alone is not useful and combined 67Ga/99mTc MDP scanning has been disappointing. Most published series support the role in 111In WBC in this situation, but not all cases are correctly diagnosed. 111In (Chloride) cannot differentiate an infected from a delayed-healing fracture. Bone scintigraphy has a significant role in determining whether a bone graft is viable or not. Reflex sympathetic dystrophy is a rare complication of a fracture; it can be diagnosed by increased periarticular uptake on bone scan in all the joints of the affected part. Bone scintigraphy, especially when done with SPECT, is a very sensitive test for the diagnosis of avascular necrosis (AVN).     

Detectability of metastatic bone tumor by Ga-67 scintigraphy

Ga-67 scintigrams in patients with malignant diseases sometimes reveal uptake of the tracer in the bone metastases. Detectability of Ga-67 scintigraphy for metastatic bone tumors and benign bone lesions was compared with that of Tc-99m bone scintigraphy. Countable bone metastases detected by bone scintigraphy were evaluated whether the lesion showed apparent, faint, or negative Ga-67 uptake. Of 47 lesions 23 (49%) showed apparent uptake and 17 (36%) showed negative uptake. On the other hand, of 71 benign bone lesions, only 7 (10%), mostly fracture/osteotomy, showed apparent uptake of the tracer. Uptake in the other benign lesions such as trauma of the ribs, spondylosis deformans, and arthrosis deformans was rather faint. In patients with multiple bone metastases, 9 patients (82%) out of 11 showed more prominent abnormal findings in Tc-99m MDP bone scintigraphy than in Ga-67 scintigraphy; that is, Ga-67 scintigraphy was not able to reveal all metastatic bone lesions. In patients with untreated or recurrent tumors, relation between Ga-67 uptake in the tumors and that in the bone metastases was evaluated. Of 7 patients with negative Ga-67 uptake in the primary tumors, 5 showed positive Ga-67 uptake in the bone metastases; that is, there seemed to be little relation between Ga-67 affinity to the primary tumors and that to the bone metastases. Mechanisms of the Ga-67 uptake in the bone metastases were discussed. Not only the tumor cells or tissues in the bone metastases but also bone mineral or osteoclasts might be the deposition sites of Ga-67.     

Abnormal pulmonary accumulation of indium-111 chloride in pneumocystis carinii pneumonia as detected by bone marrow scintigraphy

PURPOSE: Unusual pulmonary uptake of In-111 chloride in a patient with Pneumocystis carinii pneumonia and autoimmune hepatitis is described. METHOD: In-111 chloride bone marrow scintigraphy was performed to evaluate the bone marrow activity associated with pancytopenia in a 56-year-old woman with autoimmune hepatitis. RESULTS: An In-111 chloride bone marrow scan showed increased pulmonary uptake predominantly in both upper lung fields. P. carinii pneumonia was seen to be developing as an immunocompromised complication after treatment for autoimmune hepatitis. CONCLUSION: When In-111 chloride bone marrow scintigraphy shows increased uptake in the lungs of immunocompromised patients, a combined opportunistic inflammatory disease such as P. carinii pneumonia should be considered in the diagnosis.     

Detection of acute osteomyelitis with indium-111 labeled white blood cells in a patient with sickle cell disease

A young patient with sickle cell disease (SCD) and multiple hospitalizations for crisis was admitted because of suspected osteomyelitis. Initial laboratory work, radiographs, and bone images were not contributory. An In-111 white blood cell (WBC) study demonstrated two areas of increased radionuclide uptake consistent with osteomyelitis. One of these had associated soft tissue infection. No other areas of active osteomyelitis were visualized, in spite of the presence of several additional infection sites. Imaging with In-111 WBC is probably not justified for routine diagnosis of acute osteomyelitis in areas free of previous disease, where conventional bone images are highly efficient. In-111 WBC imaging, however, may be helpful in detecting osteomyelitis in selected patients with SCD in whom Tc-99m bone images and radiographs are usually abnormal and difficult to interpret due to previous bone infarcts. Localization of the infection focus is very important in choosing the aspiration site for bacteriologic studies. A negative study, however, should be interpreted cautiously.     

Detection of osteomyelitis at fracture nonunion sites: comparison of two scintigraphic methods

Forty-nine patients with 50 fracture nonunions 4-48 months after injury underwent technetium-99m methylene diphosphonate (99mTc-MDP) scintigraphy on day 1, combined 99mTc-MDP and indium-111 leukocyte (111In-WBC) scintigraphy on day 2, and gallium-67 (67Ga) scintigraphy on day 3. The results were compared to evaluate the relative abilities of these scintigraphic techniques to detect osteomyelitis. Nine patients had clinical evidence of infection at the time of imaging, and 40 patients (41 fractures) did not. Open-biopsy cultures were performed at all fracture sites and were positive at 21 (42%) of the 50 sites. Combined 99mTc-MDP/111In-WBC images were interpreted with the use of two criteria. A positive study by the first criterion required 111In-WBC localization in the region of the nonunion fracture. A positive study by the second criterion required 111In-WBC localization in bone at the fracture site. The first criterion yielded a sensitivity of 84%, specificity of 72%, and accuracy of 74%; the specificity improved to 97% with an accuracy of 88% when the second criterion was used. Ten (25%) of the 40 patients thought not to have osteomyelitis by clinical criteria at the time of imaging had true-positive 99mTc-MDP/111In-WBC studies by biopsy culture results. Gallium-67 studies were interpreted as nondiagnostic if localization of radioisotope at fracture sites was equal to that with 99mTc-MDP, positive if 67Ga localization was greater than that of 99mTc-MDP, and negative if it was less than that of 99mTc-MDP. Twenty-one 67Ga studies were interpreted as nondiagnostic; 11 (52%) of the 21 had culture-positive fracture sites. The accuracy of 67Ga/99mTc-MDP imaging was 39%. Combined 99mTc-MDP/111In-WBC imaging is useful in the detection of osteomyelitis at fracture nonunion sites and improves the specificity of 111In-WBC imaging by differentiating inflammation/infection in adjacent soft tissue from osteomyelitis at the fracture site. Gallium-67 with 99mTc-MDP imaging is not sufficiently reliable in this clinical setting to be useful as an indicator for osteomyelitis.     

Clinical evaluation of indium-111-labeled leukocyte imaging in bone infection

In-111-oxine-labeled leukocyte imaging was performed on twenty-one patients suspected of having bone infection. Nine of eleven cases (82%) were diagnosed as having active infection as demonstrated by abnormal accumulation of In-111-labeled leukocytes at the site of infection. There are two false negative (18%) cases. Two cases without active infection showed abnormal uptake. Four cases revealed cold defects on the scintigraphy. Marked uptake of radiotracer was noted not only in the case of acute osteomyelitis with acute septicaemia but also in the case with persistent chronic active osteomyelitis. It was observed that for precise evaluation of the test results it was equally important to compare the imaging findings with physical signs and laboratory investigations. It is concluded that In-111-oxine-labeled leukocyte imaging is a useful tool for the evaluation of the progression of bone infection.     

Indium-111 WBC scan in acute toxic centrilobular hepatic necrosis

In this case of prolonged fever and abnormal liver functions, dual tracer scintigraphy with In-111 WBCs and Tc-99m SC led to a biopsy-proven diagnosis of severe acute toxic hepatitis (hepatocellular necrosis). Correlation of the Tc-99m SC scan findings with those previously reported for "pseudotumors" of the liver is discussed. A "pseudonormal" scan pattern is described for the In-111 WBC scintigraphy. Discordance between In-111 WBC and Tc-99m SC scintigraphy in this clinical setting should raise the possibility of hepatic necrosis as a diagnostic alternative to hepatic abscess.     

Evaluation of a 3-hour indium-111 leukocyte image as a surrogate for a technetium-99m nanocolloid marrow scan in the diagnosis of orthopedic infection

OBJECTIVES: This is a retrospective study to evaluate a 3-hour In-111-labeled leukocyte image as a surrogate for a Tc-99m nanocolloid marrow scan in the investigation of suspected orthopedic infection using In-111 leukocyte scintigraphy. METHODS: Images from 51 patients who had received contemporaneous In-111-labeled leukocyte scintigraphy and Tc-99m nanocolloid marrow scintigraphy were reviewed. Initially, the 3-hour and 22-hour In-111-labeled leukocyte images were compared. Sites of abnormal uptake on the 22-hour image were correlated with the 3-hour image and were graded according to the level of concordance or discordance. One week later, the Tc-99m nanocolloid images and 22-hour In-111-labeled leukocyte images of the same patients were compared and graded for concordance or discordance. When discrepancies in grading arose between the observers, a consensus opinion was achieved after additional review of the images a week later. RESULTS: On inspection of the 22-hour In-111 leukocyte images, 93 sites of focal, potentially abnormal leukocyte accumulation were identified. When the grading system was reduced to simply "concordant" or "discordant," there was good agreement between the observers in the majority of cases, with kappa statistics 0.77 for Tc-99m nanocolloid versus 22-hour In-111-labeled leukocyte images and 0.78 for 3-hour versus 22-hour In-111-labeled leukocyte images. Using the comparison of the Tc-99m nanocolloid marrow scan and the 22-hour In-111-labeled leukocyte images to identify concordance or discordance as the "gold standard" for scintigraphic evaluation of suspected orthopedic infection, comparison of the 3-hour In-111-labeled leukocyte images with the 3-hour In-111-labeled leukocyte images gave a sensitivity of 77%, a specificity of 77%, and an accuracy of 77%. CONCLUSIONS: A 3-hour image is helpful using In-111-labeled leukocyte scintigraphy.     

In-111-labeled leukocyte scintigraphy in suspected orthopedic prosthesis infection: comparison with other imaging modalities

When infection of prosthetic orthopedic implants is suspected, optimal management requires accurate confirmation or exclusion of infection. The authors retrospectively studied 98 patients with possible infection who underwent scanning with indium-111-labeled white blood cells (WBCs) and subsequently underwent surgery within 14 days. At surgery, 50 patients had infections, as determined by means of culture or histologic results. The diagnostic accuracy of In-111 scanning was compared with that of plain radiography, arthrography, three-phase bone scanning, and various clinical and laboratory findings classically associated with infection. Positive findings on In-111 WBC scans and elevated erythrocyte sedimentation rates were found to be the most predictive variables in the diagnosis of septic prostheses (P less than or equal to .001 and P less than or equal to .002, respectively). Likelihood ratio analysis more clearly demonstrated the superiority of In-111 WBC scanning, with positive and negative scans yielding likelihood ratios of 5.0 and 0.16, respectively.     

Indium-111-chloride and three-phase bone scintigraphy: a comparison for imaging experimental osteomyelitis

To investigate the utility of indium-111-chloride (111In-Cl) imaging in detecting osteomyelitis complicating surgical or fracture sites, the proximal tibia of 11 dogs were experimentally infected with Staphylococcus aureus after creation of a cortical defect. The contralateral limb served as a sham-operated control. Animals were serially imaged by radiography, three-phase technetium-99m-methylene diphosphonate (99mTc-MDP) scintigraphy, and 111In-Cl scintigraphy. There was a significant difference between infected (1.93) and noninfected (1.32) limb's tibia/femur count density ratios on 24-hr (p = 0.0001) and 72-hr (p = 0.0001) 111In-Cl images. A smaller difference was found for 99mTc-MDP bone-phase tibia/femur ratios (p = 0.0199). Using receiver operator characteristic analysis of tibia/femur ratios, a sensitivity of 61%, specificity of 88%, and positive (75%) and negative (79%) predictive values were determined for the 24-hr 111In-Cl images. Indium-111-chloride was superior to 99mTc-MDP in differentiating infected and noninfected operative sites.     

Osteomyelitis complicating fracture: pitfalls of 111In leukocyte scintigraphy

111In-labeled leukocyte imaging has shown greater accuracy and specificity than alternative noninvasive methods in the detection of uncomplicated osteomyelitis. Forty patients with suspected osteomyelitis complicating fractures (with and without surgical intervention) were evaluated with 111In-labeled leukocytes. All five patients with intense focal uptake, but only one of 13 with no uptake, had active osteomyelitis. However, mild to moderate 111In leukocyte uptake, observed in 22 cases, indicated the presence of osteomyelitis in only four of these; the other false-positive results were observed in noninfected callus formation, heterotopic bone formation, myositis ossificans, and sickle-cell disease. These results suggest that 111In-labeled leukocyte imaging is useful for the evaluation of suspected osteomyelitis complicating fracture but must be used in conjunction with clinical and radiographic correlation to avoid false-positive results.     

High-resolution sonography of the rib: can fracture and metastasis be differentiated?

OBJECTIVE: Our aim was to evaluate whether high-resolution sonography can provide additional information concerning rib lesions compared with radiography or bone scintigraphy. MATERIALS AND METHODS: Fifty-eight patients with high-uptake rib lesions seen on bone scintigraphy were selected. Radiography and rib high-resolution sonography were performed on these patients. High-resolution sonography was performed using a linear 5-12 MHz transducer. By means of clinical history, histopathologic examination, and follow-up observation, these patients were classified into rib fracture (n = 37), rib metastasis (n = 18), or unknown (n = 3) groups. High-resolution sonography images of the 55 proven cases were reviewed for the presence of five representative findings: cortical disruption, callus formation, cortical deformity, mass, or bone destruction. The frequencies of these findings were compared between the groups with fracture and metastasis. RESULTS: Rib lesions were matched by bone scintigraphy and high-resolution sonography in 53 (96%) of 55 patients and by bone scintigraphy and plain radiography in 23 (42%) of 55 patients. High-resolution sonography revealed 17 (94%) of 18 patients with metastasis and 36 (97%) of 37 patients with rib fractures. Metastatic lesions were seen as mass formation (n = 13) and irregular bone destruction (n = 7) on high-resolution sonography. Fracture was seen as cortical disruption with or without hematoma (n = 17), callus formation (n = 9), or cortical deformity, such as angling or stepping (n = 12). CONCLUSION: High-resolution sonography of the ribs is a useful method of characterizing rib lesions in patients who have hot-uptake lesions on bone scintigraphy.     

The 'hot halo' sign. Pyogenic pericarditis on In-111 leukocyte scintigraphy.

The authors report a patient with diffuse pyogenic pericarditis and focal myoendocarditis initially detected using In-111 WBC scintigraphy. The patient was in septic shock after hemodialysis for the treatment of chronic renal failure. This was preceded by clinical signs and symptoms of pericarditis thought to be viral in nature. Initial investigations found no septic focus, and the patient was referred for In-111 WBC scintigraphy. This revealed a striking "halo" of increased activity around the heart, strongly suggesting bacterial pericarditis. A subsequent pericardiocentesis yielded 400 ml of purulent material, confirming the diagnosis.     

Value of bone scintigraphy in patients with carpal trauma

OBJECTIVE: We planned this study to evaluate the role of bone scintigraphy in patients with suspected carpal fracture and normal or suspicious radiographs following carpal injury. METHODS: Three-phase bone scintigraphy using Tc-99m-MDP was performed on 32 patients with negative radiographs but clinically suspected fracture at two weeks after the trauma. Focally increased radiopharmaceutical uptake was interpreted as a fracture. The final diagnosis was established with clinical follow-up. RESULTS: Twelve (38%) patients had a normal scan excluding fracture. Twelve patients had a single fracture. Multifocal fracture was present in 8 (25%) patients. Eight patients showed scaphoid fractures; of these three showed single scaphoid fracture, and the other five patients revealed accompanying fractures. Distal radius fractures and carpal bone fractures other than scaphoid were both observed in 12 patients. These were eleven fractures of distal radius; three fractures of pisiform; two fractures of hamate; and single fractures of lunate, trapezium and triquetrum. In one patient there was fracture of a first metacarpal bone. CONCLUSION: In patients with suspected carpal bone fracture and normal or suspicious radiographs, bone scintigraphy can be used as a reliable method to confirm or exclude the presence of a scaphoid fracture and to detect clinically unsuspected fractures of distal radius and other carpal bones.     

Radionuclide bone imaging in spondylolysis of the lumbar spine in children

Bone scintigraphy and radiography were performed in seven children with back pain. Six of the children with radiographic evidence of a pars interarticularis defect also had abnormal scintigrams. Increased uptake of the bone imaging agent occurred at six of the ten sites of radiographic pars interarticularis defects, implying increased bone metabolic activity. However, the location of scintigraphic abnormalities did not correspond to the location of radiographic abnormalities in several cases. Possible explanations for the discordant findings are: (a) normal bone metabolism at the site of an old spondylolysis and (b) radiographically inapparent stress fractures. Measurements of absorbed radiation dose indicate that plain radiography, including oblique views where appropriate, has a lower absorbed radiation dose than scintigraphy or tomography and should be performed prior to these studies.     

Indium-111 chloride for detecting suspected hepatomas in patients with focal defects on technetium-99m sulfur colloid liver imaging

Twenty-three patients with hepatic cirrhosis and focal defects on Tc-99m sulfur colloid (SC) scintigrams were restudied with In-111 chloride to determine if indium localization in the focal defect is indicative of a hepatoma. Seven of eight patients with proven hepatomas had positive studies; however, six of 15 patients without hepatomas also had studies interpreted as positive. Thus, In-111 chloride is highly sensitive for the detection of hepatomas, and a negative indium study would militate against this diagnosis. The high false-positive rate found may be due to technical factors rather than a lack of specificity of localization; the experience of others seems to support this impression. At present, In-111 chloride scintigraphy for focal hepatic defects appears to be useful in ruling out hepatoma.