Frederick L. Weiland

99mTc Anti-CD 15 Monoclonal Antibody (LeuTech) Imaging Improves Diagnostic Accuracy and Clinical Management in Patients With Equivocal Presentation of Appendicitis

BackgroundAppendicitis frequently presents in an atypical fashion leading to misdiagnosis or a delay in diagnosis. This is particularly true in early cases where the patient may be erroneously discharged from an emergency department and will invariably return with perforated appendicitis. The standard of care is hospital admission for observation or early operation. Adjunctive imaging tests have been used with mixed results in this equivocal patient population. The authors studied a promising new monoclonal antibody, 99mTc-labeled anti-CD 15 (LeuTech; Palatin Technologies, Inc., Princeton, NJ), which specifically targets neutrophils and may be used for imaging appendicitis. This prospective, multicenter, open-label study evaluated the diagnostic efficacy and clinical impact of LeuTech scintigraphy for detecting appendicitis in patients with an equivocal presentation. MethodsA total of 200 patients (121 females, 79 males; age range 5–86 years; mean age 30.5 ± 16.5 years) completed the study. Management plan was formulated before and reassessed following LeuTech imaging to determine impact on management. Following intravenous injection of LeuTech, the abdomen was imaged with a standard gamma camera for 30 to 90 minutes. ResultsFifty-nine patients had a histopathologic diagnosis of acute appendicitis. LeuTech identified 53 of 59 patients with appendicitis (90% sensitivity) and was negative in 122 of 141 patients without appendicitis (87% specificity). Accuracy, positive predictive value, and negative predictive value were 88%, 74%, and 95%, respectively. Diagnostic efficacy was unchanged in a subgroup of 48 pediatric patients (5–17 years). Diagnostic images for appendicitis were achieved within 8 minutes postinjection in 50% of patients and within 47 minutes in 90% of patients. Significant shifts in patient management decisions were evident following LeuTech results. LeuTech was well tolerated with no serious adverse events reported. ConclusionLeuTech is a convenient, safe, rapid, and sensitive imaging test for diagnosis of appendicitis and favorably impacts patient management in adult and pediatric patients with equivocal signs and symptoms.

Radionuclide bone imaging in the differential diagnosis of head and neck lesions: A preliminary report

The use of technetium 99m pyrophosphate (99mTcPP) imaging in the evaluation of benign and malignant tumors of the head and neck has been limited. In a clinical prospective study, twenty-one patients with suspected benign or malignant lesions of the temporomandibular joint, temporal bone, maxilla, or mandible were evaluated with regard to clinical presentation, radiographic findings, preoperative 99mTcPP bone scan, and final pathologic diagnosis. Eleven of twenty-one patients had positive scans at the site of biopsy-proven disease. In three cases, a bone scan was the single positive diagnostic test prior to surgical intervention. 99mTcPP imaging offers an additional noninvasive technique in the preoperative evaluation of patients with lesions of the osseous structures of the head and neck.

Hepatic imaging: a comparison of Tc-99m-sulfur colloid and PIPIDA in the detection of defects.

A prospective investigation comparing Tc-99m-PIPIDA with Tc-99m-sulfur colloid in the detection of defects of the liver was carried out in 30 volunteers. By acquiring images of 1 million counts from 5-10 minutes postinjection, high quality hepatic images could be obtained with PIPIDA. Separate interpretations by three nuclear physicians yielded similar results between paired PIPIDA and sulfur colloid studies (KAV = 0.95 ± .09, P <0.001). Early multiview imaging of the liver in the course of hepatobiliary evaluation with PIPIDA may yield valuable information relative to the presence of lesions.

Technetium-99m red blood cell blood-pool imaging in functional asplenia due to leukemic infiltration

Tc-99m labeled RBC blood-pool and Tc-99m sulfur colloid imaging were performed in a patient with chronic myelogenous leukemia (CML) in blast crisis. Functional asplenia was demonstrated on the sulfur colloid study despite intact organ perfusion as demonstrated by blood-pool imaging. Tc-99m RBC blood-pool imaging appears to be an ideal noninvasive technique to document intact spleen perfusion in functional asplenia.