Antonio Centi Colella

Scintigraphic evaluation of disease activity in rheumatoid arthritis: a comparison of technetium-99m human non-specific immunoglobulins, leucocytes and albumin nanocolloids

Technetium-99m-labelled, non-specific, polyclonal, human immunoglobulin G (99mTc-hIG) has been used to quantify synovial inflammation in rheumatoid arthritis. A comparison was carried out between the scintigraphic results obtained with this tracer, 99mTc-hexamethylpropylene amine oxime-labelled white blood cells (99mTc-WBC) and 99mTc-albumin nanocolloids (99mTc-NC). Twenty patients affected by rheumatoid arthritis and suffering from clinically active synovitis were studied with 99mTc-hIG. The number and sites of the involved joints had been previously assessed on the basis of the presence of pain and/or swelling. A radiological examination had already been carried out on all the joints. Two days after the 99mTc-hIG scan, 10 patients (group 1) underwent 99mTc-WBC scintigraphy and the other 10 (group 2) underwent a 99mTc-NC scan. The results show that the results of 99mTc-hIG and99m Tc-NC scans are in agreement with clinical examinations in the majority of cases. However, a certain number of positive joint scans corresponding to negative clinical examinations was found. The numerical distribution of these results according to the radiological stages seems to show that99m Tc-hIG is more useful than 99mTc-NC in the initial phases of the disease. The 99mTc-WBC scan was negative in a consistent percentage of the joints previously assessed as clinically and 99mTc-hIG scan positive.

99Tcm-sestamibi scintimammography in patients with suspicious breast lesions : Comparison of SPET and planar images in the detection of primary tumours and axillary lymph node involvement

Planar scintimammography with 99Tcm-sestamibi (99Tcm-MIBI) has been shown to be useful in diagnosing breast carcinoma. The aim of this study was to compare single photon emission tomography (SPET) and planar imaging for scintimammography with 99Tcm-MIBI in the detection of primary breast cancer and axillary lymph node involvement. Sixty-three females with mammographically suspicious lesions and 12 controls were evaluated. Dynamic images were acquired commencing immediately after the injection of the radiopharmaceutical, followed by multiple planar images in the supine and prone positions plus SPET supine imaging. A final histopathological diagnosis was achieved after surgery. A total of 66 breast lesions were considered. No focal uptake of 99Tcm-MIBI was observed in the breasts or axillas of the controls. In the patients with breast cancer, the sensitivity was 92.9% (39/42) for SPET, 71.4% (30/42) for supine and 85.7% (36/42) for prone planar imaging, respectively; the specificity was 87.5% for SPET and 91.6% for the planar scans. Metastatic axillary lymph node involvement was seen in 19 patients: the sensitivity was 84.2% (16/19) for SPET and 63.2% (12/19) for planar images; the specificity was 91.3% and 95.7%) respectively. Our results confirm the high diagnostic accuracy of 99Tcm scintimammography in the diagnosis of breast cancer, and suggest that SPET is more sensitive than planar images, especially in detecting axillary lymph node involvement.

Technetium-99m sestamibi myocardial tomography based on dipyridamole echocardiography testing in hypertensive patients with chest pain.

The non-invasive diagnosis of coronary artery disease in hypertensives with chest pain is an important clinical concern because all exercise-dependent tests display limited feasibility and diagnostic accuracy; by contrast, dipyridamole echocardiography testing has been shown to have a similar feasibility and accuracy in hypertensive and normotensive subjects. The aim of this study was to evaluate the diagnostic capability of technetium-99m sestamibi tomography based on dipyridamole echocardiography testing in hypertensives with chest pain, and to compare the scintigraphic results with those of coronary angiography, exercise electrocardiography and dipyridamole echocardiography. Forty subjects with mild to moderate hypertension, chest pain and no previous myocardial infarction were submitted to99mTc-sestamibi tomography (at rest and after high-dose dipyridamole echocardiography) and to exercise electrocardiography testing. At coronary angiography 22 patients (group A) had significant epicardial coronary artery disease (≥70% stenosis of at least one major vessel) and 18 normal main coronary vessels (group B). Dipyridamole99mTc-sestamibi imaging was positive in 21/22 patients of group A and in 5/18 of group B. Dipyridamole echocardiography was positive in 18/22 patients of group A and in 5/18 of group B. Exercise electrocardiography was positive in 15/22 patients of group A and in 11/18 of group B. Four out of five subjects in group B with positive results in all the tests showed a slow run-off of angiographic contrast medium, probably due to small-vessel disease. Significant epicardial coronary artery disease in hypertensives with chest pain is unlikely when dipyridamole99mTc-sestamibi tomography is negative. When scintigraphy is positive, either epicardial coronary artery disease or a small-vessel disease condition is possible. The association of scintigraphy with dipyridamole echocardiography testing allows the assessment of contractile function and myocardial perfusion by a single pharmacological stress.

Myocardial Scintigraphy with 99mTc-Sestamibi in Children with Kawasaki Disease

Kawasaki disease (KD) is a systemic vasculitis syndrome of early childhood. It involves particularly the coronary arteries and may cause aneurysms and thrombotic occlusions. Echocardiography is the most useful method of detecting coronary aneurysms. Nevertheless, obstructive lesions are difficult to evaluate and often need invasive coronary angiography. An important feature of this disease is the possibility of finding coronary pathology several years after the onset. This characteristic makes KD an important cause of coronary artery disease (CAD) in young adults. Thus patients with KD and previously diseased coronary arteries should be kept under long-term control. However, coronary angiography is invasive and cannot be performed repeatedly, espe cially in young patients. As an alternative, thallium 201 scintigraphy has been employed, but its low-energy photons are suboptimal for standard gamma-camera imaging, particularly in children aged less than three years. To verify the usefulness of a noninvasive assessment of myocardial perfusion, the authors used rest and dipyridamole 99mTc-Sestamibi scan in 15 children (ranging from one to six years of age) with Kawasakis cardiac involvement. Coronary aneurysms have been demonstrated by echocardiography in 12 patients; 8 patients were also submitted to cardiac catheterization. The sensitivity of 99mTc-Sestamibi imaging for detection of overall coronary lesions was 88% and the specificity was 93%. These data suggest that rest/dipyridamole 99mTc-Sestamibi scintigraphy is an accurate and noninvasive method for the detection and follow-up of Kawasakis cardiac damage even in patients aged one year.

Clinical evaluation of the99mTc-diethyl-HIDA plasma clearance curve and observations on the third exponential term

SummaryBlood clearance curves of99mTc-HIDA have been evaluated in 18 healthy volunteers and 55 patients affected by chronic liver diseases. The slope (K) of the third exponential term of the blood clearance curve can be considered as an index of the99mTc-diethyl-HIDA liver cell uptake; therefore, this parameter seems to be able to discriminate healthy volunteers from patients affected by hepatocellular dysfunction.