Indium-111 labeled leukocyte imaging following hepatic artery embolization

The use of In-111 labeled leukocytes for abscess localization is becoming well established. The first report of In-111 imaging following hepatic embolization is presented. A 45-year-old man with adenocarcinoma of the colon and metastatic liver disease was treated for intractable pain using particulate embolization of the hepatic artery. In-111 leukocyte imaging was performed to rule out abscess formation. The distribution of the labeled leukocytes demonstrated hepatic uptake commensurate with Tc-99m sulfur colloid (SC) images. Areas of embolization did not accumulate tracer. Pathologic examination at autopsy correlated with the distribution of the labeled leukocytes. Thus, therapeutic embolization did not alter the normal distribution of this tracer in functional hepatic tissue.     

False-positive 111In-labeled leukocyte scan in cystic fibrosis.

A false-positive 111In-labeled leukocyte scan was obtained in a girl with cystic fibrosis and infection. There was focal accumulation of 111In activity in the abdomen and marked pulmonary uptake. Surgical exploration and postmortem examination revealed no abdominal abnormality. The abnormal activity was apparently due to swallowed sputum which contained labeled leukocytes. Broader clinical implications are discussed.     

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.     

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.     

Distribution of leukocytes labeled with In-111 oxine in dogs with acute inflammatory lesions

The biodistributions of In-111 oxine (with and without leukocyte labeling) of Ga-67 citrate and of In-111 chloride were compared in 30 dogs with chemical and bacterial abscesses and acute joint inflammation. Serial blood samples were taken and tissues radioassayed at 24 hr. The concentration of In-111-oxine leukocytes in all three types of inflammatory lesion was invariably much higher than that of Ga-67 injected simultaneously. For bacterial abscesses, the mean abscess-to-muscle concentration ratio was 3,000 for labeled leukocytes and 72 for Ga-67. Aqueous buffered In-111 oxine sulfate solution appeared better for labeling leukocytes than In-111 oxine in ethanol. When In-111 oxine was not incubated with leukocytes before injection, or if the cells were poorly labeled or damaged, the abscess localization was often inferior to that of gallium. Localization of In-111 chloride also appeared inferior to that of gallium. No significant difference in distribution in the major organs or inflammatory lesions was demonstrable between labeled suspensions of "pure"neutrophils harvested by elutriation and "mixed"cell suspensions of leukocytes after erythrocyte sedimentation with hydroxyethyl starch. For both types of leukocyte suspension labeled with In-111 oxine, the average recovery of cell-bound activity in the circulating blood at 4 hr was 32% of the administered activity, inferior to that of DFP-32. It is concluded, therefore, that In-111 oxine is a more effective agent than Ga-67 for the detection of acute focal inflammatory lesions if leukocytes are properly labeled, but current techniques are unsatisfactory for the study of neutrophil kinetics.     

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.     

Unsuspected extra-abdominal sites of infection: scintigraphic detection with indium-111-labeled leukocytes

Scintigraphy with indium-111-labeled leukocytes (In-111-WBC) was assessed in 128 patients with suspected abdominal-pelvic abscesses. Studies were positive in 37 of 41 patients with proved abscesses, in two of two with infected aortic grafts, and in 12 of 15 with other infections; studies were negative in 63 of 70 cases without infection. The sensitivity of leukocyte scintigraphy in this series was 88%, specificity 90%, and accuracy 89%. Sixteen percent of all patients studied with In-111-WBC scintigraphy had unexpected sites of infection outside the abdomen. Of the 58 patients with proved infection, 20 (34%) had alterations in diagnostic evaluations and therapeutic regimens due to such findings.     

Bone marrow island vs focal infection. An indium-111 leukocyte imaging dilemma

An island of bone marrow surrounded by the glue used in securing a hip prosthesis accumulated In-111 leukocytes in a patient being imaged for hip pain. This was shown to be normal marrow uptake of labeled cells and not an abscess by performing bone marrow imaging. The appearance of the leukocyte and bone marrow scans of the area were identical.     

False-positive early indium-111 leukocyte scan

An In-111 leukocyte scan was performed in a cirrhotic patient with ascitic fluid infection to rule out an abdominal abscess. Scintigraphy showed localized uptake in the area between the liver and right lung 30 minutes after reinjection of the labeled cells. The 24-hour study was negative. No purulent collection was demonstrated in any location.     

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.     

Tc-99m HMPAO-labeled leukocytes for hematopoietic marrow imaging. Comparison with In-111 chloride.

The current study was initiated to define whether Tc-99m leukocyte imaging, compared to In-111 chloride imaging, could provide additional information on the hematopoietic activity of the bone marrow in diffuse hematologic disorders. A total of 11 patients with hematologic disorders were studied both with Tc-99m leukocytes and In-111 chloride. One patient with myelofibrosis showed disparate tracer distribution in the bone marrow between the two; Tc-99m leukocyte uptake in the central marrow was highly decreased, whereas In-111 chloride showed expanded marrow. The disparate results of granuloid hypoplasia and erythroid hyperplasia obtained by bone marrow biopsy and aspiration in this patient were thought to give an explanation for the radionuclide findings. The remaining 10 patients showed similar tracer distribution in the marrow, and the observation of hematopoietic cellularity confirmed by bone marrow biopsy and aspiration correlated well with the radionuclide findings. These results demonstrate that Tc-99m leukocytes may be a potential imaging agent for evaluating hematopoietic activity in the bone marrow, in particular granulopoietic activity.     

Colonic localization of indium-111 labeled leukocytes in active Behcet's disease

A patient with known Behcet's disease demonstrated intense colonic localization of In-111 labeled leukocytes. Gastrointestinal involvement had not been previously manifested, but extensive colonic inflammation was documented by endoscopy. This case illustrates the utility of In-111 labeled leukocyte imaging for detecting active bowel disease in a debilitated patient with documented Behcet's vasculitis.     

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.     

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.     

Role of in-111 labeled leukocyte scintigraphy in the diagnosis of intracerebral lesions

The differential diagnosis of intracerebral enhancing lesions on contrast computed tomography includes tumors, abscesses, and cerebrovascular accidents. Particularly important is the differentiation between tumor and abscess. While In-111 labeled leukocyte imaging is an accurate test for identification of foci of infection in general, the role of this procedure in the evaluation of the intracranial lesion is not well established. We undertook a retrospective review of 16 patients with contrast enhancing intracerebral lesions identified on computed tomography, who were also studied with labeled leukocyte imaging. Final diagnoses were: abscess (n = 2), primary brain tumor (n = 6), metastasis (n = 4), dermoid cyst (n = 1), and cerebral infarct (n = 3). There were two positive labeled leukocyte studies; both were cerebral abscesses. No labeled leukocyte activity was identified in any of the tumors or infarcts. We conclude that In-111 labeled leukocyte imaging is an accurate method of differentiating infectious from noninfectious causes of intracerebral lesions identified on computed tomography.     

Subacute splenic abscess. Appearance on indium-111 leukocyte, gallium-67, and technetium-99m sulfur colloid imaging

A case of a 23-year-old man with an encapsulated, anaerobic splenic abscess is reported. Both the In-111 leukocyte and Tc-99m sulfur colloid scans demonstrated an intrasplenic defect. The Ga-67 citrate scan revealed uptake in the rim of the abscess only where the abscess cavity was relatively photon-deficient. The combined Tc-99m sulfur colloid/In-111 leukocyte/Ga-67 scan appearance of a subacute splenic abscess has not been described previously. In cases suspected to be splenic abscesses the combined In-111 leukocyte/Tc-99m sulfur colloid imaging is the most useful.     

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.     

Diagnosis of musculoskeletal infection using combined In-111 labeled leukocyte and Tc-99m SC marrow imaging.

Seventy-three patients with various underlying disorders that could potentially alter distribution of bone marrow underwent In-111 labeled autologous leukocyte and Tc-99m SC marrow imaging to exclude musculoskeletal infection. There were 22 cases of infection among the 73 patients studied. When interpreted in isolation, labeled leukocyte images were considered positive for infection when uptake of labeled cells in the region of interest exceeded uptake in the corresponding contralateral side. The sensitivity, specificity, and accuracy of the study using this criterion were 86%, 12%, and 34%, respectively. When interpreted in conjunction with sulfur colloid marrow images, studies were considered positive for infection when uptake in the region of interest on leukocyte and marrow images was spatially incongruent. The sensitivity, specificity, and accuracy of this dual tracer modality were 100%, 94%, and 96%, respectively. Three patients with infection and abnormal leukocyte/marrow images underwent repeat imaging after appropriate therapy. Images were interpreted as normal in two of them; both were infection free at subsequent surgery. Images of the third patient were interpreted as consistent with persistent infection, and operative cultures grew out Staphylococcus aureus. In summary, combined leukocyte/marrow imaging is a highly accurate method for diagnosing musculoskeletal infection and overcomes certain inherent limitations of labeled leukocyte imaging alone.     

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.     

Improved detection of upper abdominal abscesses by combination of 99mTc sulfur colloid and 111In leukocyte scanning

Indium-111-labeled leukocyte scanning is an excellent technique for detecting abdominal abscesses. However, since labeled leukocytes are normally taken up by the liver and spleen, diagnosing upper abdominal abscesses can be difficult. A prospective study was undertaken to see if having a technetium-99m sulfur colloid liver-spleen scan to compare with the 111In leukocyte scan would improve the reader's ability to diagnose or exclude upper abdominal abscesses. Ninety patients with suspected upper abdominal abscesses were examined with 111In leukocyte scans followed immediately by conventional 99mTc sulfur colloid liver-spleen scans in the same projections. In 57% of patients with upper abdominal abscesses and 26% of all patients studied, the 99mTc sulfur colloid scan was essential to diagnose or exclude an upper abdominal abscess. The liver-spleen scan was considered helpful in another 13%. The addition of a 99mTc sulfur colloid liver-spleen scan to the 111In leukocyte study is useful when evaluating patients with suspected upper abdominal abscesses.