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A new method for assessing 99Tcm-MDP bone uptake from a bone scan image : quantitative measurement of radioactivity in global skeletal regions of interest

Bone uptake of 99Tcm-MDP was evaluated 4 h after injection in 27 normal subjects aged 23-50 years by gamma camera measurement of the activity in whole skeleton regions of interest (ROIs) in anterior and posterior projection. The mean global skeletal uptake (GSU) (% of whole-body activity in both projections measured 30 s after injection) was 33.5 +/- 4%. The standard urinary excretion method (whole-body retention, WBR) gave a mean bone uptake value of 31.5 +/- 4%. A significant correlation (r = 0.570; P less than 0.002) was found between GSU and WBR. The mean bone-to-soft tissue ratio (B/S index) was 3.0 +/- 1.1. It is suggested that this direct, external counting method provides a way of obtaining both a qualitative and a semiquantitative evaluation of bone uptake with a single tracer administration in a routine bone scan. Investigation of its use in the assessment of bone involvement in low and high turnover bone diseases is now under way.

I-131 MIBG scintigraphy of neuroectodermal tumors: comparison between I-131 MIBG and In-111 DTPA octreotide

An account is given of the results observed with 1-131 MIBG scintigraphy in four patients (1 bladder pheochromocytoma, 3 neuroblastomas) chosen on account of their particular clinical and diagnostic interest from a series of 41 apudoma patients examined by means of this technique. In the first patient, the unusual site of the tumor in the posterior wall of the bladder meant that its detection by 1-131 MIBG was only possible after catheterizatlon of the bladder. In the second patient, uptake in the metastasis was only evident after removal of the primary tumor. In the third patient, the scintiscan revealed several metastases (some in bone) not detected by CT. In the fourth patient (congenital neuroblastoma), enhanced uptake accompanied the appearance of high plasma catecholamlne and urinary vanillylhandelic acid values, suggesting a functional switch from a nonsecret- Ing to a secreting form. A supplementary ln-111 DTPAOctreotide (OCT) scintiscan of this patient demonstrated the presence of somatostatln receptors on the neuroblasts. Thus, this examination would seem particularly useful for the differentiation of nonsecretlng neuroblastomas. Its employment in assessment of the therapeutic capacity of OCT itself is also suggested.

Correlation between bone imaging and the clinical picture in two unsuspected cases of progressive diaphyseal dysplasia (Engelmann's disease).

Progressive diaphyseal dysplasia was incidentally discovered in two patients referred for Tc-99m MDP bone scintigraphy (one for intense sciatica, the other for the detection of breast cancer metastases). Tracer accumulation in the diaphyses of the lower limbs and the base of the skull was accompanied by bone thickening and patency of the medullary cavity, as demonstrated by radiography, MRI, and bone marrow scanning. Comparison of the clinical pictures with the results of instrumental examinations showed that these were cases of sporadic progressive diaphyseal dysplasia of slight and average gravity, respectively. The differentiation of Ribbings disease is explained and reference also is made to a finding not mentioned in the literature, namely frontal bone resorption lacunules in one patient.

99Tcm-HMPAO SPET and 1H-MRS (proton magnetic resonance spectroscopy) in patients with ischaemic cerebral infarction.

SummaryBrain 99Tcm-HMPAO single photon emission tomography (SPET) and 1H-MRS (proton magnetic resonance spectroscopy) were used to determine correlations between alterations in regional cerebral blood flow (rCBF) and changes in neuronal metabolites in 21 patients (28 examinations) with ischaemic cerebral infarction examined in different phases. rCBF was determined semi-quantitatively using Lassens linearization algorithm. SPET provided evidence of the hypoperfused site of necrosis within a few hours after the acute event and alterations in rCBF were detected in both the infarcted and diaschistic areas at all stages. 1H-MRS was used to monitor the concentration of the following metabolites: N-acetyl-aspartate (NAA), creatine and phosphocreatine (CR+PCr), compounds containing choline (Cho) and lactate (Lac). A significant correlation was found between reduction in rCBF and a fall in NAA and Cr+PCr in both the acute and chronic phases, but not during ‘luxury perfusion’ in the subacute phase. The presence of LAC in the infarcted area up to 9 months post-ictus was totally unexpected. Simultaneous SPET and 1H-MRS thus provides additional information regarding the physiopathogenesis of cerebral ictus by clarifying the relation between alterations in rCBF and biochemical neuronal changes. We believe that NAA and Cr+PCr concentrations are the best expression of agreement between flow and metabolism in infarcted areas, particularly with regard to hypoperfused areas not clearly detectable by magnetic resonance imaging in the early post-ictus stage.

99Tcm-MDP global skeletal uptake and markers of bone metabolism in patients with bone diseases.

99Tcm-methylene diphosphonate (MDP) global skeletal uptake (4 h GSU) was determined by quantitative measurement of activity on bone scan images 4 h after injection in whole skeleton regions of interest (ROI) in 16 normal subjects, in five patients with hypertrophic pulmonary osteoarthropathy (HPO) and in 12 with Pagets disease. Values were correlated with those of whole body retention (24 h WBR), and serum bone gla protein (BGP), i.e. osteocalcin, alkaline phosphatase (AP) and type 1 procollagen (P1CP). They were 40% higher in HPO than in the normal controls, while in Pagets disease they increased more in polyostotic than in monostotic patients. A statistically significant difference was noted between 4 h GSU and 24 h WBR values in the two groups of patients compared with the controls. Of the bone metabolism markers, serum AP and P1CP were higher in the patients and positively correlated with their enhanced 4 h GSU values, whereas BGP was always within the normal range. This method may thus be regarded as a useful way of simultaneously determining bone 99Tcm-MDP uptake and altered bone turnover sites, especially in patients with systemic bone disease.

Pituitary adenomas: the role of 111In-DTPA-octreotide SPET in the detection of minimal post-surgical residues.

Scintigraphy with 111In-DTPA-octreotide (111In-octreotide) enables the localization of tumours with somatostatin receptors on their cell membranes, of which pituitary adenomas are an example. Trans-sphenoidal excision of such tumours is sometimes incomplete and the detection of post-surgical residues is a difficult diagnostic task. In this study, we used 111In-octreotide SPET to visualize pituitary adenomas and their minimal residues. In positive cases, the indirect demonstration of the presence of somatostatin receptors may be decisive for the planning of treatment. 111In-octreotide SPET was able to visualize adenomas in 21 of 27 patients (77.7%) (10 GH-secreting, 10 PRL-secreting and 1 non-secreting). Repeat SPET after the recurrence of clinical symptoms and hormone hypersecretion revealed intense 111In-octreotide uptake by residues in 8 of 10 patients (4 GH-secreting and 6 PRL-secreting). Magnetic resonance imaging was positive in only 3 of these 10 patients. Our results suggest that 111In-octreotide SPET, in combination with other imaging modalities, is useful in the diagnosis and follow-up pituitary adenomas. It ensures better selection of patients for treatment with somatostatin analogues, both pre- and post-operatively, and assists in the development of personalized treatment plans.

Scintigraphy in assessment of the feasibility of separation of a set of xipho-omphalopagous conjoined twins

An account is given of the assessment of a set of xlphoomphalopagous twins by means of Tc-99m microcoiloid human serum albumin (HSA) and Tc-99m HIDA scintigraphy before their successful separation. The Tc-99m HSA examination showed the absence of connections between the two hearts and major vessels, as well as the independent vascularization of each liver parenchyma and absence of substantial intrahepatic shunts. Tc-99m HIDA disclosed bile secretion and the existence of intrahepatic ducts in both twins. In one, there was excretion into the intestine and the gallbladder and common bile duct were visualized, whereas in the other excretion was slow, either because of duct hypoplasia or as a result of the connections with the other twin. On separation, it was found that the liver parenchyma was composed of two fused parts (the livers of each twin). In one twin, cholangiography showed the gallbladder and Intrahepatic and extrahepatic bile ducts with normal excretion into the intestine and excellent drainage, whereas in the other twin the gallbladder was absent, the common bile duct was hypopiastic, and excretion was poor. The two scintigraphlc techniques employed provided evidence of bile duct function and enabled the separation to be planned, while intraoperative cholangiography gave a clear picture of the anatomical details before the reconstruction procedure.

Technetium 99m furifosmin regional myocardial uptake in patients with previous myocardial infarction: relation to thallium-201 activity and left ventricular function.

BackgroundThis study was designed to compare the results of rest-redistribution thallium-201 imaging with those of rest technetium 99m furifosmin single photon emission computed tomography in the same patients with chronic ischemic left ventricular (LV) dysfunction.MethodsTwenty-one patients (mean age 62±9 years) with chronic myocardial infarction and LV dysfunction (mean LV ejection fraction 34%±8%) underwent rest-redistribution thallium imaging and resting furifosmin single photon emission computed tomography on the same day. In each patient, regional thallium and furifosmin activity was quantitatively measured in 13 myocardial segments. Regional LV function was assessed in corresponding segments by echocardiography.ResultsAt thallium imaging, 91 (33%) segments had normal uptake, 16 (6%) showed reversible defects, and the remaining 166 (61%) irreversible defects. Of these 166 irreversible defects, 74 (45%) had moderate (≥58% of peak activity) and 92 (55%) severe (<58% of peak activity) reduction of thallium uptake. Regional furifosmin uptake was significantly related to both rest (r=0.87, P<.0001) and redistribution (r=0.90, P<.0001) thallium activity. Agreement in the evaluation of regional perfusion status between thallium and furifosmin imaging was observed in 70% of the 84 hypokinetic segments (κ=0.54) and in 76% of the 78 akinetic or dyskinetic segments (κ=0.60). Concordance in the detection of myocardial viability between thallium and furifosmin imaging was observed in 69 (82%) of hypokinetic regions (κ=0.60) and in 65 (83%) of akinetic or dyskinetic regions (κ=0.67).ConclusionsThese results suggest that in patients with chronic coronary artery disease and LV dysfunction, quantitative rest-redistribution thallium scintigraphy and furifosmin tomography at rest provide similar results in the evaluation of perfusion status and in the detection of myocardial viability.

Tc-99m nanocolloid and MRI evaluation of extramedullary hematopoiesis in thalassemia major

Tc-99m nanocolloid bone marrow scintigraphy of a patient with thalassemia major showed a high degree hepatomegaly and active bone marrow throughout the skeleton with elevated radionuclide uptake in the cranium, the pelvis, and the proximal and distal ends of both tibiae. Areas of increased nanocolloid uptake in the right paravertebral and dorsal areas were associated with sites of extramedullary erythropoiesis. MRI identified the two intrathoracic masses in the chest.