technetium-tc-99m-exametazime and Abdominal-Abscess

The diagnosis of abdominal infections and inflammations often presents considerable difficulty, and various imaging techniques may be required to localize them accurately. At present, radiolabelled leucocytes offer the most widely accepted radionuclide method for imaging inflammation. Because of the many advantages of technetium-99m (99mTc) over indium-111 (111In), 99mTc-HMPAO-leucocyte scintigraphy is preferred for the investigation of acute abdominal sepsis and inflammatory bowel disease, and 111In-leucocyte scintigraphy for more chronic infections and renal sepsis. The 99mTc-HMPAO-labelled leucocytes technique is highly accurate within the first few hours postinjection, and is therefore useful also in acutely ill patients. It is sensitive in detecting abdominal abscesses in all locations except the liver and spleen. By whole body imaging, unsuspected sites and types of infection can be found. 99mTc-HMPAO-leucocyte scan is valuable also in the investigation of acute cholecystitis in problematic situations in which ultrasound is known to give misleading results, especially in acute acalculous cholecystitis. In inflammatory bowel disease it can reliably assess disease activity, but a normal scintigraphy does not exclude mild inflammation. Leucocyte scan is useful also in suspected acute appendicitis, acute diverticulitis, pelvic inflammatory disease, aortic graft infection, etc. But infection and inflammation cannot reliably be differentiated, which may cause misinterpretations in the early postoperative period. Radionuclide techniques have an important role to play in the investigation of abdominal sepsis if the nuclear medicine department can offer instant investigations when the clinical problem is acute.

Topics: Abdomen; Abdominal Abscess; Antibodies, Monoclonal; Bacterial Infections; Gallium Radioisotopes; Humans; Leukocytes; Organotechnetium Compounds; Oximes; Radionuclide Imaging; Sepsis; Technetium Tc 99m Exametazime

Topics: Abdominal Abscess; Abdominal Pain; Adult; Crohn Disease; Diagnosis, Differential; Female; Humans; Incidental Findings; Leukocytes; Nocardia Infections; Radionuclide Imaging; Radiopharmaceuticals; Technetium Tc 99m Exametazime

Pelvic infection is a rare but well-known complication following IVF procedures with a reported incidence <1%. A case of multiple abdominal abscesses following IVF procedure was established by Tc-99m-HMPAO-labeled leukocyte scintigraphy and confirmed by laparotomy. This imaging technique should be recommended for early and precise diagnosis of pelvic infection following IVF.

Topics: Abdominal Abscess; Adult; Female; Fertilization in Vitro; Humans; Leukocytes; Pelvic Infection; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The diagnostic accuracy of technetium-99m-HMPAO-labeled leukocyte scintigraphy (LS) and spiral CT for the detection of inflammatory activity was assessed; the extent of the inflammation and the complications were compared with the clinical and laboratory parameters and with the endoscopic and radiological findings in patients with clinically active Crohn's disease (CD).. Twenty-eight patients (13 men, 15 women, average age 32.5 yr, range: 18-59 yr) with an acute exacerbation of CD were enrolled in the study. The disease behavior type and the maximum extent of inflammation were established by means of endoscopy (jejunoscopy and colonoscopy) and enteroclysis. Nine patients with severe complications (abscess and stenosis) underwent operation. The GI tract was divided into five segments (small bowel, ascending colon, transverse colon, descending colon, and rectosigmoid), the LS, CT, endoscopic, and radiological pictures of all segments were graded (range: 0-3) and the scores were summed and compared.. The investigations indicated that LS and CT had sensitivities of 76.1% and 71.8%, specificities of 91.0% and 83.5%, and accuracies of 82.6% and 77.5%, respectively, for detection of segmental inflammatory activity. With regard to the disease behavior type, the sensitivities of LS and CT were, respectively, 77% and 100% in the penetrating-fistulizing, 80% and 73% in the stricturing, and 68% and 64% in the inflammatory form of CD. CT detected all abdominal abscesses, whereas the diagnostic value of LS for the detection of the complications of CD was lower. The inflammatory activity scores measured by LS displayed a closer correlation than that of CT with the Best index (r = 0.71, p < 0.0005 vs r = 0.63, p < 0.001), the van Hees index (r = 0.61, p < 0.005 vs r = 0.59, p < 0.005), the serum fibrinogen level (r = 0.67, p < 0.005 vs r = 0.59, p < 0.005), or the C-reactive protein level (r = 0.64, p < 0.005 vs r = 0.51, p < 0.01).. Both LS and CT are valuable noninvasive diagnostic methods in cases involving severe, active CD. LS seemed better for the detection of segmental inflammatory activity, whereas CT displayed excellent suitability for the recognition of complications: abdominal abscesses were diagnosed with 100% efficiency.

Topics: Abdominal Abscess; Adult; Crohn Disease; Female; Humans; Leukocytes; Male; Middle Aged; Organotechnetium Compounds; Oximes; Radionuclide Imaging; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Tomography, X-Ray Computed

Computed tomography (CT) and magnetic resonance imaging (MRI) are excellent modalities for imaging patients with localizing signs of an intra-abdominal abscess. However, radionuclide techniques have an advantage over CT and MRI because they can evaluate the entire body for infection. In addition, radionuclides can noninvasively differentiate infection and inflammation from benign fluid collections. Radiopharmaceuticals available for imaging abdominal infection include gallium-67 citrate, indium-111, and technetium-99m-labeled leukocytes, and radiolabeled whole antibodies. The use of these radiopharmaceuticals for abdominal imaging is dependent on their biodistribution and mechanism of abscess localization.

Topics: Abdominal Abscess; Antibodies, Monoclonal; Citrates; Citric Acid; Gallium Radioisotopes; Humans; Immunoglobulin G; Indium Radioisotopes; Leukocytes; Organotechnetium Compounds; Oximes; Radionuclide Imaging; Technetium Tc 99m Exametazime

Fifty patients with suspected intra-abdominal abscess were investigated prospectively with ultrasound and with 99mTc-hexamethylpropylene-amine oxime (HMPAO) isotope labelled mixed leucocytes, using 111-In tropolonate granulocyte scanning as the reference standard. Twenty five patients had inflammatory bowel disease (three were postoperative): 21 of these had Crohn's disease and four had ulcerative colitis. The remainder comprised nine with postoperative fever and 16 with fever and abdominal pain. An abscess was diagnosed when focal activity on serial 111-In tropolonate and 99m-Tc-HMPOA images at one, three, and 24 hours resulted in activity at least equal to liver activity at 24 hours. Thirteen abscesses were diagnosed using each type of white cell scanning, resulting in 100% sensitivity for 99m-Tc-HMPAO compared with 111-In tropolonate. Bowel inflammation was easily distinguished from abscess on serial images. Eight of these 13 abscesses were detected by ultrasound. Altogether 17 abscesses were found. Ultrasound detected 12, including four liver abscesses which were not purulent and had not been detected by white cell scanning. Ultrasound had a sensitivity of 71% (12 of 17) and a specificity of 87% (33 of 38) using all confirmed abscesses as the reference standard. White cell scanning showed a sensitivity of 76% (13 of 17: as a result of the four non-purulent liver abscesses) and a specificity of 100%. 99m-Tc-HMPAO scanning is as accurate as 111-In tropolonate scanning, and has several advantages including simplicity, availability, superior image quality, and reduced radiation dose. Both methods are more sensitive and specific than ultrasound for intra-abdominal abscess detection but ultrasound is advisable if a neutrophil infiltrate is not suspected.

Topics: Abdominal Abscess; Adolescent; Adult; Aged; Aged, 80 and over; Colitis, Ulcerative; Crohn Disease; Female; Granulocytes; Humans; Indium Radioisotopes; Leukocytes; Male; Middle Aged; Organometallic Compounds; Organotechnetium Compounds; Oximes; Prospective Studies; Radionuclide Imaging; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Tropolone; Ultrasonography