[Nuclear Medicine in Germany. Key data from official statistics]. / Nuklearmedizin in Deutschland. Kennzahlen aus offiziellen Statistiken.

AIM: To explain the spectrum and number of in-vivo nuclear medicine examinations and therapies based on official statistics about out-patient and in-patient care. Trends in time of the frequency and spectrum of procedures as well as data on the health care structure for nuclear medicine in Germany should be collected. METHODS: Data from the Gesundheitsberichterstattung des Bundes, from the frequency statistics of the statutory health insurance for out-patients and from the Bundesärztekammer were used. Customized queries were performed to analyse temporal changes. RESULTS: Nuclear medicine physicians are more frequently consulted by out-patients over the last years (2008: 2024498; 2009: 2164664) and the number of colleagues in private practice increased. For in-patients, the frequency of conventional nuclear medicine procedures (mainly for brain, lymphatic system, lung and heart) increased since 2008 after a decline in previous years (2009: 323515; +4.6%) and the number of PET(/CT) examinations continued to rise (2009: 25123; +18%), even if changes in OPS keys may hamper comparisons. Nearly 600 gamma cameras and 76 PET(/CT) scanners were installed in hospitals in 2008. Nuclear medicine procedures are increasingly performed as cross sectional imaging like SPECT(/CT) and PET(/CT). With the supply shortfall with 99Mo, the frequency of thyroid scans with 123I iodine increased as well as the use of 18F PET as a substitute for conventional bone scans. The number of radionuclide therapies, in particular non-thyroid treatments, increased since the mid-nineties and stabilized at nearly 50000 cases per year with shorter lengths of stay. CONCLUSION: The details of the present analysis may help to understand the positive evolution of key numbers for nuclear medicine.

Retrospective web-based multicenter evaluation of ¹8F-FDG-PET and CT derived predictive factors. Radioimmunotherapy with yttrium-90-ibritumomab tiuxetan in follicular non Hodgkin's lymphoma.

AIM: Although predictive factors (PF) for conventional lymphoma therapy are established and frequently used in clinical practice and medical research, the PF for radioimmunotherapy (RIT) have not been fully defined until now. The aim of this multicenter evaluation is to prove the feasibility of the multicenter web-based data collection and to preliminary explore imaging findings and prediction of therapy response in patients with follicular lymphoma (FL) following radioimmunotherapy (RIT) with 90Y-ibritumomab tiuxetan. PATIENTS, METHODS: We retrospectively analyzed and correlated clinical and imaging data (CT and FDG-PET) before and after RIT as documented by the RIT-Network. Evaluation of treatment response was done on both patient and lesion basis. Every measurable lesion was analyzed in terms of standardized uptake value (SUV), volume (CT and PET) and response. PF were identified using a uni- and multivariate model. A web-based system was used for the documentation and evaluation of clinical and imaging data. RESULTS: 16 patients with at least one PET before and after RIT were eligible for analysis. Concerning response three months postRIT, 5 patients achieved a CR, 6 patients a PR and 4 patients remained with NC. A total of 159 lesions were measured (mean 10±8). In the multivariate model the log lesion volume (p < 0.0001), the total (p = 0.03) and maximum lesion volume (p = 0.05) were predictors for response (CR + PR). Concerning the lesional CR initial small lesion volume (p = 0.009) and its high metabolic activity (p = 0.01) were identified as predictors. The web-based system showed no major disturbances allowing secure data transfer and central image interpretation in a reasonable time. CONCLUSION: The use of a web-based multicenter archiving system for clinical and imaging data is technically feasible in a multicenter setting and allows a central analysis. This preliminary analysis suggests that FDG-PET may predict the likelihood of response to RIT.

Physical aspects of scintigraphy-based dosimetry for nuclear medicine therapy.

In nuclear medicine therapy the treatment of tumours by radiation exposure from internally deposited labelled antibodies or labelled peptides is currently an active field of investigation. To permit the efficient delivery of high amounts of radiation dose to tumours while limiting the radiation dose to critical organs dosimetry calculations have to be performed. These are relying on scintigraphic data being input to the well known MIRD formalism. This paper focuses on the methods and the difficulties associated with the scintigraphic determination of organ kinetics. The physical properties of the well-known scintigraphic imaging modalities, PET, SPECT and planar scintigraphy, are discussed thereby taking into account the properties of the appropriate radionuclides currently being available for therapy and dosimetry. Several arguments are given and disputed for the limited clinical use of PET and SPECT in dosimetry and the ongoing preference of planar whole-body imaging as the method of choice. The quantitative restrictions still inherent to this method are also discussed in detail. Procedural recommendations are proposed covering all processes related to data acquisition, data correction and data analysis which finally lead to reliable estimations of organ dose.

Para-[(123)I]iodo-L-phenylalanine in patients with pancreatic adenocarcinoma: tumour uptake, whole-body kinetics, dosimetry.

UNLABELLED: Recently, p-[(123)I]iodo-L-phenylalanine (IPA) was clinically validated for brain tumour imaging. Preclinical studies demonstrated uptake of IPA into pancreatic adenocarcinoma suggesting its diagnostic application in patients with pancreatic tumours. The aim was to study the tumour uptake of IPA in patients with pancreatic adenocarcinoma and to analyse its biodistribution and dosimetry to assess the radiation dose resulting from its diagnostic use. PATIENTS, METHODS: Seven patients with pancreatic adenocarcinoma underwent whole-body scintigraphies and SPECT up to 24 h after administration of 250 MBq of IPA. Tumour uptake of IPA was assessed visually. Time activity curves and the corresponding residence times were determined for whole-body, kidneys, liver, spleen, lung, heart content, brain, and testes. Mean absorbed doses for various organs and the effective dose were assessed based on the MIRD formalism using OLINDA/EXM. RESULTS: IPA exhibited no accumulation in proven manifestations of pancreatic adenocarcinomas. IPA was exclusively eliminated by the urine and showed a delayed clearance from blood. Residence times were 0.26 +/- 0.09 h for kidneys, 0.38 +/- 0.19 h for liver, 0.15 +/- 0.07 h for spleen, 0.51 +/- 0.20 h for lungs, 0.22 +/- 0.07 h for heart content, 0.11 +/- 0.05 h for brain, 0.014 +/- 0.005 h for testes and 6.4 +/- 2.2 h for the remainder. The highest absorbed doses were determined in the urinary bladder wall and in the kidneys. According to the ICRP 60 the effective dose resulting from 250 MBq IPA was 3.6 +/- 0.7 mSv. CONCLUSION: Para-[(123)I]iodo-L-phenylalanine can be used in diagnostic nuclear medicine with acceptable radiation doses. Besides its proven validity for brain tumour imaging, IPA does not appear to be suitable as tracer for pancreatic cancer.

Detection of hepatocellular carcinoma with a new alpha-fetoprotein antibody imaging kit.

PURPOSE: The aim of this phase II study was to assess the clinical utility and safety of AFP-Scan (Immunomedics, Inc, Morris Plains, NJ), a technetium-99m (99mTc)-labeled anti-alpha-fetoprotein (AFP) Fab' imaging kit, in the evaluation of hepatocellular carcinoma (HCC), in comparison to computed tomography (CT). PATIENTS AND METHODS: Twenty-five consecutive patients with a history of HCC were examined by planar and single-photon emission computed tomography (SPECT) imaging at 6 and 24 hours after intravenous (I.V.) injection of 1 mg AFP-Scan labeled with 925 MBq 99mTc. RESULTS: In 20 patients, there was a specific binding of the Fab' antibody to the tumor, whereas in four patients who presented with elevated serum AFP levels, no specific targeting was found and no malignant lesions were evident by CT or biopsy. One patient was diagnosed as false-negative by AFP-Scan. In five of six patients with normal serum AFP levels, focal uptake was demonstrated. In one case, metastatic disease in the lower abdomen was found. In all patients, diagnostically relevant information was provided by the 24-hour antibody images, especially with SPECT. Comparing AFP-Scan versus CT, the former showed a higher sensitivity (95% v 63%) and specificity (67% v 17%), with an overall accuracy of 88% versus 52% for AFP-Scan versus CT, even in patients with normal serum AFP titers. No adverse reactions or human antimouse antibody (HAMA) elevations were found in any of the patients. CONCLUSIONS: AFP-Scan appears to be a promising new antibody imaging kit for the disclosure of sites of HCC and should aid in the management of these patients by revealing primary, recurrent, and metastatic disease with a single imaging modality.

Influence of right ventricular stimulation site on left ventricular function in atrial synchronous ventricular pacing.

OBJECTIVES: The study investigates the correlation between left ventricular function and QRS duration obtained by alternate right ventricular pacing sites. BACKGROUND: 1. Right ventricular apical pacing is associated with alterations of left ventricular contraction sequence. 2. A stimulation producing narrow QRS complexes is supposed to provide for better left ventricular contraction patterns. METHODS: Fourteen patients with third degree AV block received one ventricular pacing lead in apical position. The alternate lead was attached to that site on the septum that produced the smallest QRS complex as measured from the earliest to the last deflection in any of the orthogonal Frank leads (xyz). During atrial synchronous ventricular pacing, the AV delay was optimized individually and for each stimulation site using mitral valve doppler or impedance cardiography. By radionuclide ventriculography, the phase distribution histogram of left ventricular contraction was evaluated as area under the curve (AuC); systolic function was determined as ejection fraction (EF) and as absolute ejected counts (EC) in random order. The difference (delta) in QRS duration between apical and septal stimulation (deltaxyz) was correlated with the difference in phase distribution (deltaAuC) and ejection parameters (deltaEF, deltaEC). RESULTS: QRS duration was shorter with septal than with apical pacing in 9 out of 14 patients (64%); it was longer in 4 (29%), and no difference was seen in 1 patient. There was a significant positive correlation between the change in QRS duration (deltaxvz) and phase distribution (deltaAuC: r = 0.66393, p = 0.010) and a significant negative correlation to systolic function (deltaEF: r = 0.70931, p = 0.004; deltaEC: r = 0.74368, p = 0.002). CONCLUSIONS: In atrial synchronous right ventricular pacing, if the AV delay is adapted individually, decreased QRS duration obtained by alternate pacing sites is significantly correlated with homogenization of left ventricular contraction and with increased systolic function in acute tests.

Granulocytes and three-phase bone scintigraphy for differentiation of diabetic gangrene with and without osteomyelitis.

OBJECTIVE: In diabetic gangrene, concomitant osteopathy and soft-tissue infection often render laboratory and roentgenographic signs unreliable as indicators of osteomyelitis. In this situation, scintigraphic methods can be helpful. RESEARCH DESIGN AND METHODS: Relying on the long-term clinical course as the final indicator of presence or absence of osteomyelitis, we prospectively compared in 31 patients three-phase bone scintigraphy with either indium-labeled autologous granulocytes (n = 20) or 123I-labeled antibodies against granulocytes (n = 11). RESULTS: Three-phase bone scintigraphy and imaging with indium-labeled autologous granulocytes yielded sensitivities and specificities of 95 and 70% for bone scintigraphy and 77 and 100% for granulocyte scintigraphy, respectively. One patient with severe angiopathy and proved osteomyelitis had a negative bone scintigraphy but a positive scintigraphy with labeled antibodies against granulocytes. One patient with aseptic bone necrosis presented with a formally false positive result with both methods. CONCLUSIONS: In contrast to former retrospective studies, three-phase bone scintigraphy compares very well with granulocyte scintigraphy. The care of most patients can be managed with clinical data and this widely available scintigraphic method.

Reduced cerebral blood flow in early stages of human immunodeficiency virus infection.

In order to determine if brain perfusion abnormalities, which are known in patients with acquiredimmunodeficiency syndrome dementia, occur in early stages of human immunodeficiency virus infection, technetium 99m hexamethyl-propyleneamine oxime-single-photon emission computed tomography studies were performed in 20 patients infected with human immunodeficiency virus who belonged to Walter Reed stages I through IV. None of these patients demonstrated signs of dementia or severe neurological dysfunction. Pathological patterns of hexamethyl-propyleneamine oxime uptake were seen in 14 patients, seven of whom had normal results during neurological examination. Only four patients had signs of cerebral atrophy on cranial computed tomographic scan. These data suggest that subtle changes in cerebral perfusion seem to arise early in the course of human immunodeficiency virus infection and may indicate human immunodeficiency virus encephalopathy before neurological symptoms or noticeable structural damage occurs.

123I-iodobenzamide-SPECT in 83 patients with de novo parkinsonism.

Single photon emission computed tomography (SPECT) with 123I-iodobenzamide (123I-IBZM) was used in a prospective study to investigate 83 patients with parkinsonism (Hoehn and Yahr stages I to III) who had not been previously treated with dopamimetic drugs. All patients had clinical signs that were compatible with Parkinson's disease. An additional 13 patients had clinical signs of another basal ganglia disorder, such as progressive supranuclear palsy or multisystem atrophy. 123I-IBZM-SPECT results were compared with clinical responses to subcutaneous injections of the D1/D2-receptor agonist apomorphine (83 patients) and to long-term oral dopamimetic therapy (62 patients). Results from 123I-IBZM-SPECT predicted a positive or negative response to apomorphine in 69 of 76 patients (apomorphine responses were equivocal in 7 patients) and a response to dopamimetic therapy in 54 of 62 patients. All patients with a clinical diagnosis of progressive supranuclear palsy or multisystem atrophy had reduced 123I-IBZM binding. In six of these patients, the response to apomorphine was negative, and none clearly benefited from long-term oral levodopa therapy. Imaging of dopamine D2 receptors with 123I-IBZM-SPECT appears to distinguish between patients with de novo parkinsonism that is levodopa-responsive (probably Parkinson's disease of Lewy body type) and that which does not respond to levodopa therapy.

123I-iodobenzamide-SPECT predicts dopaminergic responsiveness in patients with de novo parkinsonism.

We used 123I-iodobenzamide-single photon emission computed tomography (IBZM-SPECT) in a prospective study to investigate 38 patients with parkinsonism (Hoehn and Yahr stage I to III) not previously treated with dopamimetic drugs. Thirty-four patients only showed symptoms of Parkinson's disease, and four patients showed, in addition, subtle clinical signs of progressive supranuclear palsy or multisystem atrophy. IBZM is a dopamine D2 receptor antagonist detectable by SPECT. We compared IBZM-SPECT results with clinical response to subcutaneous injections of the D1/D2 dopamine receptor agonist apomorphine (38 patients) and long-term dopamimetic therapy (31 patients). IBZM-SPECT results predicted a positive or negative response to apomorphine in 30 of 34 patients (apomorphine response in four patients was equivocal) and response to dopamimetic therapy in 27 of 31 patients. Thus, imaging of dopamine D2 receptors using readily available IBZM-SPECT seems to distinguish between L-dopa-responsive (most likely Parkinson's disease of Lewy body type) and L-dopa-unresponsive parkinsonism in patients not previously treated with dopamimetic drugs.

Treatment with D-penicillamine improves dopamine D2-receptor binding and T2-signal intensity in de novo Wilson's disease.

We report the results of in vivo striatal dopamine D2-receptor binding assessed by PET using 11C-raclopride (only one patient) and by single-photon emission computed tomography (SPECT) using 123I-iodobenzamide (123I-IBZM) and the findings of T2-weighted MRIs in two de novo Wilson's disease patients before and 4 months after initiation of D-penicillamine treatment. Before treatment, specific 11C-raclopride binding (only patient 1) was markedly reduced, with a putamen to cerebellum ratio of 1.99 (controls: 3.99 +/- 0.55, n = 15) and a caudate to cerebellum ratio of 2.52 (controls: 3.65 +/- 0.59, n = 15). Specific 123I-IBZM binding was reduced in both patients, with a basal ganglia to frontal cortex ratio of 1.25 (patient 1) and of 1.41 (patient 2) controls: 1.57 +/- 0.04, n = 5). After 4 months of therapy, 11C-raclopride-PET improved to a putamen to cerebellum ratio of 2.52 and a caudate to cerebellum ratio of 3.06 (patient 1). 123I-IBZM-SPECT revealed an increase of basal ganglia to frontal cortex ratios of 1.34 (patient 1) and 1.55 (patient 2). On heavily T2-weighted MRI sequences, hyperintense signal changes before therapy within the putamen (both patients), brainstem (only patient 1), and caudate (only patient 2) greatly diminished after treatment. Reduced striatal dopamine D2-receptor binding in these Wilson's disease patients improved under therapy, suggesting, in part, a reversible defect of striatal neurons.

18F-deoxyglucose positron emission tomography (FDG-PET) for the planning of radiotherapy in lung cancer: high impact in patients with atelectasis.

PURPOSE: 18F-deoxyglucose positron emission tomography (FDG-PET) is increasingly applied in the staging of lung cancer (LC). This study analyzes the potential contribution of PET in radiotherapy planning for LC with special respect to tumor-associated atelectasis. METHODS AND MATERIALS: Thirty-four patients with histologically confirmed LC, who had been examined by PET during pretreatment staging, were included. All were irradiated after CT-based therapy planning with anterior/posterior (AP) portals encompassing the primary tumor and the mediastinum (CT portals, CP). The result of the PET examination was unknown in treatment planning. In retrospect, a PET portal (PP) was delineated and compared with the CP. RESULTS: In 12/34 cases, the shape and/or size of the portals were changed, primarily (n = 10) the size of the fields was reduced. The median area of CP was 182 cm2 versus 167 cm2 of PP. Seventeen of 34 patients had dys- or atelectasis caused by a central primary tumor. In these cases, differences between CP and PP were significantly more frequent than in the other patients (8/17 vs. 3/17, p = 0.03). CONCLUSION: In this retrospective analysis, the information provided by FDG-PET would have contributed to a substantial reduction of the size of radiotherapy portals. This applies particularly for patients with tumor-associated dys- or atelectasis.

Multiple swallow test for the quantitative and qualitative evaluation of esophageal motility disorders.

Esophageal motility was evaluated from the analysis of six consecutive swallows. A sum image was generated comprising the representative information of an entire study. Calculation of emptying rates and characterization of the bolus behavior was performed from the sum image and the single swallow data. In 86 patients investigated, liquid and solid-phase studies showed a remarkable variation of single swallow data in normals (relative variation coefficient for liquid: 10%, solid: 14%), which were even higher (p less than 0.001) in patients with disorders (liquid: 31%, solid: 25%). As sum images compensate for this intra-individual variation, false-positive (liquid: 16%, solid: 25%) or negative single swallow findings (liquid: 36%, solid: 27%) are reduced. Qualitative analysis of condensed sum images provided characteristic image patterns representing different pathophysiologic aspects. Since the method introduced better discriminates between normal and pathologic function, it may enhance diagnostic accuracy.

Detection of severe cornary heart disease with TI-201: comparison of resting single photon emission tomography with invasive arteriography.

To investigate the application of TI-201 single photon emission computed tomography (SPECT) at rest in the confirmation of coronary heart disease (CHD), we studied 95 patients who had all undergone coronary angiography and cineventriculography. We separated three groups, patients with (a) prior myocardial infarction (MI) (n = 45), (b) no history of MI (n = 40), and (c) no abnormality of coronary angiogram (n = 23). The results of planar imaging with computer-assisted evaluation (scintimetry, SCM) and of SPECT with a three-plane reconstruction (transverse, sagittal, frontal) were compared with the invasive, arteriographic findings. SPECT yielded a higher sensitivity (93%) than SCM (68%) in the detection of defects in both infarcted and noninfarcted groups. The specificity was found to be almost equal in the two imaging modalities. A significant (p less than or equal to 0.01) increase in accuracy was found in SPECT in the assessment of the posterior wall (54% compared with 88%) as well as in the general detection of defects (68% compared with 88%). Applying the SPECT imaging technique increases both the diagnostic accuracy of TI-201 myocardial imaging and the anatomical association of CHD.

Quantitative multi-detector emission computerized tomography using iterative attenuation compensation.

An iterative procedure to correct for attenuation has been developed for a multidetector, single-photon emission tomographic scanner. The difference between measured and estimated data projections is used at each iteration to form an error image which is used, in turn, to correct the image. A damping factor that minimizes chi2 is applied after each iteration to speed convergence. Several phantoms of different size, with various concentration distributions, have been used to compare this method with a first-order multiplicative attenuation correction used previously with this scanner. The first-order correction is inadequate for most of the phantoms studied, whereas relative and absolute quantitative capability is demonstrated for the iterative attenuation correction. The reconstructed average number of counts per pixel is a linear function of activity concentration up to 5 muCi/ml for all regions of uniform activity whose size is greater than or equal to 5 cm. The importance of using an accurate attenuation distribution with this method is demonstrated with a torso-like phantom.

Intermediate and long-term side effects of high-dose radioiodine therapy for thyroid carcinoma.

UNLABELLED: The present investigation is an evaluation of intermediate and long-term side effects in patients after high-dose radioiodine treatment due to differentiated thyroid carcinoma. METHODS: A total of 203 patients were interviewed using a standardized questionnaire. RESULTS: After radioiodine treatment, 76.8% of the patients reported intermediate (from discharge up to 3 mo) or long-term (more than 3 mo after treatment) complaints, and 61.1% reported long-term side effects. Nonstochastic side effects included sialoadenitis, which occurred in 33.0% of cases, and 27.1% of patients suffered from a transient loss of taste or smell. More than 1 yr after the last radioiodine application, 42.9% of patients suffered from reduced salivary gland function. Complete xerostomia occurred in 4.4% of patients. Hematological abnormalities were found in 9 patients. In 28.1% of patients a transient episode of alopecia was reported. In 22.7% of patients chronic or recurrent conjunctivitis was reported, and 4 patients underwent dacryocystorhinostomy; 13.8% of patients suffered from an increased frequency of influenza, but 3.4% reported a reduced occurrence of such infections. For sialoadenitis, the loss of taste/smell and dry mouth, the dependence on accumulated activity was significant. CONCLUSION: Severe long-term side effects are rare after high-dose radioiodine treatment. Moderate side effects are common. The side effects are commonly the result of radiation damage to the salivary glands. The frequency of such complaints advocates regular protection of the salivary glands.

Dynamic SPECT with Xe-133: regional cerebral blood flow in patients with unilateral cerebrovascular disease: concise communication.

To validate xenon-133 dynamic single photon emission tomography (SPECT) clinically, 74 patients were examined. Strictly unilateral cerebrovascular disease was confirmed in 47 patients by clinical history and by transmission computerized tomography (TCT) and contrast angiography. Twenty-seven were excluded, considered normal. SPECT flow maps were evaluated visually (against TCT) or by automated region of interest (ROI) techniques (12 areas per slice) to measure area flow (AF) (ml/100 g-min) and interhemispherical area flow ratios (AR). These were compared with normal values. Minimum AF in affected hemisphere decreased, and AR-to-normal difference increased, with the severity of the disease. Visually, low-flow areas were detected twice as frequently in SPECT as areas of low density of TCT. In reversible episodes, sensitivity of AF alone ws significantly below the sensitivity of combined evaluation of flow and ratio.

Characteristics of a scanning, multidetector, single-photon ECT body imager.

We evaluated a single-photon emission computed tomographic system using ten scanning detectors in a circular array. The system uses focusing collimators that scan radially as well as tangentially. The spatial resolution in the tomographic plane is 2.6 cm FWHM and the axial resolution is 3.3 cm FWHM. The resolution is independent of position within the field of view, and nearly independent of energy through 511 keV. Sensitivity was found to be 4600 cps/muCi-ml for an extended phantom, 20-cm in diameter, filled with Tc-99m; 7200 cps/muCi-ml with TI-201; and 8000 cps/muCi-ml with Ga-67. Investigations of positional uniformity indicated some quantitative distortion of data due to inadequate attenuation correction. Improvement in the attenuation correction is necessary before truly quantitative tracer distribution studies are undertaken.

Simultaneous assessment of bolus transport and contraction parameters in multiple-swallow investigations.

A better understanding of scintigraphic findings may lead to a wider acceptance of esophageal transit studies. The purpose of this study, therefore, was to correlate standard manometric parameters with the quantitative and qualitative characteristics of liquid and semi-solid bolus transport. Twenty-nine patients were simultaneously investigated with esophageal scintigraphy and manometry. Single-swallow and sum-image data of six consecutive swallows were analyzed. No significant relationship between transit time and the velocity of the peristaltic wave could be identified, which suggests that factors other than peristaltic velocity (e.g., pharyngeal pump) essentially modulate esophageal transit. There was also no linear correlation between esophageal emptying and peristaltic amplitudes. Emptying was normal in patients with amplitudes greater than 30 mmHg and reduced in those with amplitudes less than 30 mmHg. This suggests that a threshold pressure greater than 30 mmHg is necessary to propel a test bolus adequately. Patterns in condensed images have been shown to specifically reflect the events in corresponding manometric recordings. Normal and different pathologic types of peristalsis presented analogous findings in both modalities. Thus, an analysis of the relationship between bolus transport and contraction parameters in simultaneous studies increases understanding of quantitative and qualitative scintigraphic results.

Measurement of infarct size using single photon emission computed tomography and technetium-99m pyrophosphate: a description of the method and comparison with patient prognosis.

The application of dual tracer transaxial emission computed tomography of the heart was studied with use of technetium-99m pyrophosphate and technetium-99m-labeled red blood cells for measuring infarct size in 20 patients with acute myocardial infarction and 10 without infarction. Imaging was performed with a standard gamma camera and with a multidetector transaxial emission computed tomographic body scanner 3 hours after injection of technetium-99m pyrophosphate. Immediately after the scanning procedure, technetium-99m pertechnetate was injected to label red blood cells, and the scanning protocol was repeated. Technetium-99m pyrophosphate was detected in the anterior wall with involvement of the interventricular septum or lateral wall in patients with electrocardiographic criteria for anterior infarction, whereas uptake was detected in the diaphragmatic left ventricular wall with involvement of the posterior, posteroseptal or posterolateral left ventricle or of the right ventricle in patients with electrocardiographic criteria for inferior or posterior infarction. Infarct size measured from transaxial images ranged from 14.0 to 117.0 g in weight. There was a direct relation between infarct size and patient prognosis in that, of the 13 patients with infarct greater than 40 g, 11 (85 percent) had complications, whereas only 2 (29 percent) of 7 patients with an infarct less than 40 g had complications during a follow-up period averaging 17.8 months (p less than 0.05).