Postoperative bone marrow alterations: potential pitfalls in the diagnosis of osteomyelitis with In-111-labeled leukocyte scintigraphy.

Scintigraphy was used after injection of technetium-99m methylene diphosphonate (MDP) and indium-111-labeled white blood cells (WBCs) to assess for the presence of osteomyelitis in 97 patients who had undergone prior surgical procedures. Thirty-four patients with abnormal In-111-labeled WBC patterns underwent restudy with Tc-99m albumin colloid (AC). Scintigraphic findings were considered positive for osteomyelitis whenever localization of In-111-labeled WBCs exceeded Tc-99m AC activity in extent or focal intensity (discordant pattern). Ten of 12 patients with culture-proved osteomyelitis had discordant patterns; two had false-negative (concordant) patterns. The cases of 20 of 22 patients without infection who were considered to have osteomyelitis on the basis of patterns of In-111-labeled WBCs and Tc-99m MDP were reclassified correctly on the basis of concordant patterns of In-111-labeled WBCs and Tc-99m AC. Radiocolloid images improved the overall scintigraphic specificity for osteomyelitis from 59% without bone marrow imaging to 92%; sensitivity decreased from 94% to 88%.     

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 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.     

In-111-labeled white blood cell uptake in noninfected closed fracture in humans: prospective study

Since indium-111 white blood cell (In-111 WBC) scintigraphy is often used to evaluate for osteomyelitis in bone fractures, it is important to know if noninfected fractures have In-111 WBC uptake. Twenty-seven noninfected closed fracture sites in 19 patients were prospectively evaluated with technetium-99m methylene diphosphonate bone scintigraphy and In-111 WBC scintigraphy. In-111 WBC uptake was present in 41% of the 27 sites. In the 11 positive sites, the In-111 WBC uptake was 1+ (definite but minimal) in 55%, 2+ (moderate) in 36%, and 3+ (marked) in 9%. The visual intensity of the radioactive uptake on In-111 WBC scintigrams relative to that on bone scintigrams was less in 82%, equal in 9%, and greater in 9%. The visual size of the area of uptake on In-111 WBC scintigrams and bone scintigrams was smaller in 36%, equal in 55%, and greater in 9%. Factors that may help distinction of In-111 WBC uptake due to fracture alone from infection associated with fracture are discussed.     

Abdominal patterns of indium-111 labeled leukocyte imaging

In-111 oxine WBC abdominal scanning is now a widely accepted technique for the detection of abdominal infectious processes. High sensitivity and specificity are achieved. In-111 labeled leukocyte accumulation, however, does not always suggest the diagnosis of abscess. Higher specificity could be obtained by the knowledge of the In-111 leukocyte distribution pattern in the abdomen in other pathologic states like inflammation of abdominal wounds, stoma; surgical complication without abscess formation; inflammatory or ischemic bowel disease; or swallowing leukocytes which subsequently are visualized in the intestinal lumen. One hundred fifty-two consecutive WBC scans performed over 18 months were reviewed and classified according to their pattern of uptake: 96 cases showed no abdominal uptake, and 56 had accumulation of leukocytes in the abdomen. Twenty-eight of these patients had proven abdominal abscess, and the remaining 26 were positive due to other causes. This report briefly discusses the distribution pattern of In-111 labeled leukocytes in the latter patients and compares the results obtained using different diagnostic criteria.     

Skeletal photopenic lesions in In-111 WBC imaging

Four cases of skeletal photon-deficient areas in In-111 white blood cell (In-111 WBC) images are reported. These were found in patients with lymphoma, vertebral osteomyelitis, and following radiotherapy and extensive surgical procedures. We emphasize that these photopenic lesions, although uncommon, may represent tumor involvement or benign processes, including osteomyelitis. Possible mechanisms to explain this phenomenon are discussed.     

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.     

Deep venous thrombophlebitis: detection with 4-hour versus 24-hour platelet scintigraphy

Thirty-one nonheparinized patients with suspected deep venous thrombophlebitis (DVT) underwent contrast venography and indium-111 platelet scintigraphy (In-111 PS). Venography permitted identification of acute DVT in 12 of 31 cases (39%). One additional patient was considered to have acute DVT despite nonconclusive venography results. In-111 PS results were positive at 4 hours in nine of 13 cases (69%) and at 24 hours in 12 of 13 cases (92%). Two of four patients with false-negative 4-hour In-111 PS studies had received warfarin. Thus, the sensitivity of 4-hour In-111 PS in patients not receiving anticoagulants was 82%. Venography results were negative for acute DVT in 18 cases, and 4-hour In-111 PS studies were negative or equivocal in each. In-111 PS is an alternative to contrast venography for detecting acute DVT. If 4-hour In-111 PS results are positive, anticoagulation can be initiated. Delayed images are necessary if the 4-hour images are negative or equivocal.     

Fused SPECT/CT imaging of Peri-iliopsoas infection using Indium-111-labeled leukocytes

Nuclear imaging with In-111-labeled leukocytes has become an instrumental tool in localizing sites of infection and is superior to Ga-67 in localizing abdominal and pelvic abscesses resulting from absence of a normal bowel excretory pathway. Labeled white blood cells (WBCs) localize at sites of infection through diapedesis, chemotaxis, and enhanced vascular permeability and can thus be used to identify infection. The accuracy of this functional imaging modality can be enhanced by fusing SPECT images of labeled WBC with CT images that provide anatomic detail to facilitate reading as illustrated in the case described.     

The complementary role of indium-111 labeled leukocyte imaging,ultrasonography and computed tomography in the evaluation of postoperative infection or abscess

We report our experiences with the combined use of indium-111 labeled leukocyte imaging (In-III WBC scan.), computed tomography (CT) and ultrasonography (US) for evaluation of suspected postoperative infection or abscess, and discuss the complementary roles of these modalities. Postoperative abscesses or infections were diagnosed in 9 of 20 patients. All patients were correctly diagnosed by In-111 WBC imaging and 4 patients could not be diagnosed by US because of bowel gas. One false-positive CT examination and another artifact on CT images due to respiratory movements were obtained. The three modalities were found to be complementary: CT and US were efficient imaging methods for diagnosis and treatment of abscess. In-111 WBC imaging could estimate the activity of inflammation.     

Unusual presentation of a large infected hemophiliac pseudotumor in an autologous indium-111 WBC scan

A false-negative In-111 WBC scan was obtained in a case of a large, infected hemophiliac pseudotumor. Following aspiration of the abscess, a positive scan was seen, demonstrating that In-111 WBC imaging occasionally may be misleading as a diagnostic tool.     

Indium-111 labeled leukocyte uptake: false-positive results in noninfected pseudoaneurysms

Indium-111 (In-111) leukocyte scintigraphy was performed in two patients with postsurgical pseudoaneurysms as part of preoperative evaluation for evidence of graft infection. Despite positive In-111 uptake by the pseudoaneurysms, surgical and pathologic examinations failed to reveal any evidence of infection. The most likely explanation for the false-positive results is the labeling of "contaminating" platelets and erythrocytes in the leukocyte mixture. Caution must be exercised in interpretation of In-111 leukocyte scans in patients with postsurgical pseudoaneurysms.     

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.     

Indium-111 labelled white blood cell scintigraphy in cranial and spinal septic lesions

Cranial and spinal infections are severe events that require timely diagnosis and treatment. Physical and neurological examination, laboratory tests and radiological imaging may be insufficient for assessing cranial and spinal septic lesions. This study aimed to evaluate the accuracy of indium-111 white blood cell (WBC) scan in assessing the presence of leucocytes in intracranial and spinal lesions, and in the diagnosis, management and follow-up of primary, post-traumatic and post-surgical infections. One hundred and twenty-four subjects were included in the study (48 with post-traumatic or post-surgical lesions, 73 with primary cerebral lesions, and 3 with spinal lesions). All patients underwent a diagnostic work-up including planar scans with 111In-labelled WBCs, at 4 and 24 h post tracer injection. All subjects underwent surgical treatment. Patients who did not recover from the infection as suggested by clinical evolution underwent further treatment (up to three times) and further WBC scans (up to four times). WBC scintigraphy correctly identified all the areas of leucocyte accumulation, as confirmed after surgery. WBC scintigraphy also correctly excluded the presence of leucocytes in all other lesions, as demonstrated at surgery. The results of this study confirm the accuracy of WBC scan for the assessment of patients with cranial and spinal lesions, in whom the demonstration of leucocyte accumulation can ease the diagnosis of infection, and indicate that the method is also accurate for the follow-up and management of neurosurgical patients.     

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.     

Indium-111-labeled white blood cells in the detection of osteomyelitis complicated by a pre-existing condition

Forty-six patients (23M, 23F) ranging in age from 19 to 79 yr with a clinical history of a nonunion fracture, surgery, diabetes or a soft-tissue infection were studied with [111In]oxine WBCs to detect osteomyelitis. There were 27 true-positive, nine true-negative, two false-positive and one false-negative. The false-positives and the false-negative occurred in patients with soft-tissue infections overlying the area of interest. All diagnoses were confirmed by intraoperative bone biopsies and cultures. Bone biopsy and scan were performed within 2 days of each other in 39 patients. The overall sensitivity was 97% (27/28), specificity, 82% (9/11) and the diagnostic accuracy, 92% (36/39). The remaining seven patients had negative [111In]WBC scans several months after positive bone biopsies and definite antibiotic treatment. This suggests that [In]WBC scans become negative after appropriate therapy is undertaken. Interobserver data was obtained from four nuclear physicians of varying experience blinded to clinical information. A high degree of agreement was found in over 90% of the cases. This study demonstrates the utility of [111In]WBC scans in the diagnosis and follow-up of complicated osteomyelitis and a high level of interobserver agreement in scan interpretation.     

Indium-111 labelled white blood cell scintigraphy in cranial and spinal septic lesions

Cranial and spinal infections are severe events that require timely diagnosis and treatment. Physical and neurological examination, laboratory tests and radiological imaging may be insufficient for assessing cranial and spinal septic lesions. This study aimed to evaluate the accuracy of indium-111 white blood cell (WBC) scan in assessing the presence of leucocytes in intracranial and spinal lesions, and in the diagnosis, management and follow-up of primary, post-traumatic and post-surgical infections. One hundred and twenty-four subjects were included in the study (48 with post-traumatic or post-surgical lesions, 73 with primary cerebral lesions, and 3 with spinal lesions). All patients underwent a diagnostic work-up including planar scans with ¹¹¹In-labelled WBCs, at 4 and 24 h post tracer injection. All subjects underwent surgical treatment. Patients who did not recover from the infection as suggested by clinical evolution underwent further treatment (up to three times) and further WBC scans (up to four times). WBC scintigraphy correctly identified all the areas of leucocyte accumulation, as confirmed after surgery. WBC scintigraphy also correctly excluded the presence of leucocytes in all other lesions, as demonstrated at surgery. The results of this study confirm the accuracy of WBC scan for the assessment of patients with cranial and spinal lesions, in whom the demonstration of leucocyte accumulation can ease the diagnosis of infection, and indicate that the method is also accurate for the follow-up and management of neurosurgical patients.     

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.     

Human platelets labeled with In-111 8-hydroxyquinoline: kinetics, distribution, and estimates of radiation dose

Platelets from nine normal male subjects were labeled with In-111 8-hydroxyquinoline (In-111 oxine) in the presence of plasma in either "closed" blood transfer packs or in "open" test tubes. The mean labeling efficiencies in these two systems were 27 and 53%, respectively. Mean survival time of In-111-labeled autologous platelets was 8.76 days, with a standard deviation of 1.05 according to the maximum-likelihood estimate of the gamma-function model. The initial recovery of In-111 platelets in the circulation was 57% with a standard deviation of 11%. The distribution of In-111 platelets in liver and spleen was quantitated by anterior, posterior, and transmission gamma-camera imaging. During the first 30 min, 38% of the injected dose accumulated in the spleen, 13% in the liver. No significant increase in In-111 radioactivity was observed in either of the two organs over a 3-9-day period. The bone marrow was an additional site of In-111 accumulation. The spleen was the critical organ with respect to radiation dose. The splenic dose was estimated to be 34 rad/mCi In-111 platelets, that of the liver 2.1 rad/mCi. With the injection of 100-150 microCi of In-111-labeled platelets in normal subjects, giving a splenic radiation of 5 rad, a complete 10-day survival study can be performed and uptake of In-111 in different organs can be measured quantitatively for at least 3-4 days.     

Importance of Tc-99m sulfur colloid liver-spleen scans performed before indium-111 labeled leukocyte imaging for localization of abdominal infection

INTRODUCTION: The localization of intraabdominal abscesses is a difficult imaging problem in nuclear medicine, especially when the location of the abscess is in the area of the liver and spleen. The need for performing Tc-99m sulfur colloid liver-spleen scans before injecting indium-111 leukocytes for improved lesion detection and characterization versus performing In-111 leukocyte scans alone has been questioned in the literature MATERIALS AND METHODS: We present 3 patients with intraabdominal abscesses in the liver-spleen area, in which liver-spleen scans were performed before In-111 leukocyte scans. The findings of all were correlated with computed tomography and interventional procedures. RESULTS: In all patients, the Tc-99m liver-spleen scan helped for accurate recognition of the location of the abscess, correlated with computed tomography findings, and were helpful for intervention and exclusion of the other sources of infection. CONCLUSION: Data from these 3 patients reinforces the need for Tc-99m sulfur colloid liver-spleen scans before performing In-111 WBC scans for better localization and interventional treatment of intraabdominal abscesses.