Body surface area determined by whole-body CT scanning: need for new formulae?

Calculation of the estimated body surface area (BSA) by body height and weight has been a challenge in the past centuries due to lack of a well-documented gold standard. More recently, available techniques such as 3D laser surface scanning and CT scanning may be expected to quantify the BSA in an easier and more accurate way. This study provides the first comparison between BSA obtained from post-mortem whole-body CT scans and BSA calculated by nine predictive formulae. The sample consisted of 54 male cadavers ranging from 20 to 87 years old. 3D reconstructions were generated from CT scans using Mimics software, and BSA values were automatically extracted from the program. They were compared with nine predictive equations from the literature. Remarkably, close correlations (r > 0·90) were found between BSA values from CT scans and those from the predictive formulae. A mean BSA of the 54 cadavers of 1·84-1·87 m2 was calculated by all formulae except one, SD values varying between 0·171 and 0·223 m2 . T-tests revealed significant differences between mean BSA values calculated with CT and three of the formulae. Regression analyses showed intercepts >(0;0) and slopes <1·0 using all predictive equations, with the CT scan determination as gold standard. It is concluded that DuBois and DuBois' equation can be safely used in normal-weight male subjects with high accuracy, but it seems likely that BSA is underestimated in underweight subjects and overestimated in overweight individuals. Creation of new formulae specific for overweight subjects and children may be needed.

Radioguided Surgery for Localization of Nonpalpable Breast Lesions A Mini-Review.

The majority of patients with nonpalpable breast lesions are eligible for breast conserving surgery guided by some kind of lesion localization. The current standard is wire-guided localization (WGL) even though it has several disadvantages, the most important one being the considerable proportion of patients with insufficient resection margin. These patients require a reoperation. New methods in the field of radioguided surgery (RGS) have been developed including radioguided occult lesion localization (ROLL) and radioactive seed localization (RSL). Especially RSL is a very promising technique. Guided by ultrasound a small titanium seed containing typically 1-10 MBq of radioactive iodine-125 is placed in the centre of the nonpalpable breast lesion. During the operation the seed is located with a hand-held gamma probe. To date, only few cohort studies exist on the feasibility of RSL, and the method has only been tested in one randomized trial. The results are either equal to or superior to those obtained with WGL, with regards to achieving free margins and low reoperation rates. Additionally, the RSL technique is less unpleasant for the patient and more flexible regarding preoperative logistics. The seed can be placed a few days before surgery, in contrast to the wire used in WGL, which has to be placed within few hours of surgery. RSL has quickly become popular in surgical and radiological teams that have used the technique and will probably become an important tool for preoperative localization of nonpalpable breast lesions in the near future.

Preparation and Administration of I-125 Labeled Seeds for Localization of Nonpalpable Breast Lesions.

UNLABELLED: Radioactive seed localization (RSL) is a new technique for surgical identification of non-palpable breast lesions. We describe the preparation of the needle with I-125 seeds for ultrasound-guided deposition in breast lesions. In a feasibility study we investigated the minimum activity amount needed for reliable gamma probe identification of the seeds and the levels of exposure to the staff. METHODS: 11 patients received a seed, which was manually placed in an 18 gauge needle with bone wax occluding the tip, and the radiologist introduced it into the breast tissue guided by ultra-sound. The seed was located during the operation with a handheld gamma probe. The activity amount required was studied in a water bath. Radiation exposure to the fingertips of pathologists was measured by a thermoluminescent dosemeter. RESULTS: All seeds were successfully prepared, positioned in the breast lesion, and easily identified. The surgeon removed the seeds together with the breast lesions, and they were identified by the pathologist. There were no unexpected adverse drug reactions. Water bath studies suggest that 1-3 MBq I-125 was sufficient for precise identification, regardless of the presence of conventional Tc- 99m activity from sentinel node injection. The total finger dose exposure to the pathologists for the 8 procedures was below the detection limit of 0.1 mSv. CONCLUSION: I-125 seeds for ultrasound-guided deployment and surgical identification of breast lesions were successfully prepared and identified for this promising new radioguided surgical technique. The radiation exposure to staff involved is considerably below the permissible limits and almost negligible.

EANM procedural guidelines for radionuclide myocardial perfusion imaging with SPECT and SPECT/CT: 2015 revision.

Since the publication of the European Association of Nuclear Medicine (EANM) procedural guidelines for radionuclide myocardial perfusion imaging (MPI) in 2005, many small and some larger steps of progress have been made, improving MPI procedures. In this paper, the major changes from the updated 2015 procedural guidelines are highlighted, focusing on the important changes related to new instrumentation with improved image information and the possibility to reduce radiation exposure, which is further discussed in relation to the recent developments of new International Commission on Radiological Protection (ICRP) models. Introduction of the selective coronary vasodilator regadenoson and the use of coronary CT-contrast agents for hybrid imaging with SPECT/CT angiography are other important areas for nuclear cardiology that were not included in the previous guidelines. A large number of minor changes have been described in more detail in the fully revised version available at the EANM home page: http://eanm.org/publications/guidelines/2015_07_EANM_FINAL_myocardial_perfusion_guideline.pdf .

Reporting nuclear cardiology: a joint position paper by the European Association of Nuclear Medicine (EANM) and the European Association of Cardiovascular Imaging (EACVI).

The report of an imaging procedure is a critical component of an examination, being the final and often the only communication from the interpreting physician to the referring or treating physician. Very limited evidence and few recommendations or guidelines on reporting imaging studies are available; therefore, an European position statement on how to report nuclear cardiology might be useful. The current paper combines the limited existing evidence with expert consensus, previously published recommendations as well as current clinical practices. For all the applications discussed in this paper (myocardial perfusion, viability, innervation, and function as acquired by single photon emission computed tomography and positron emission tomography or hybrid imaging), headings cover laboratory and patient demographics, clinical indication, tracer administration and image acquisition, findings, and conclusion of the report. The statement also discusses recommended terminology in nuclear cardiology, image display, and preliminary reports. It is hoped that this statement may lead to more attention to create well-written and standardized nuclear cardiology reports and eventually lead to improved clinical outcome.

Radionuclide leakage monitoring during hyperthermic isolated limb perfusion for treatment of local melanoma metastasis in an extremity.

INTRODUCTION: The aim is to describe the importance of leakage monitoring in hyperthermic isolated limb perfusion (ILP). It is generally recommended that leakage should not exceed 10% because of risk of systemic toxicity. MATERIAL AND METHODS: Data retrieved by retrospective analysis of 131 perfusions performed in 115 consecutive patients (77 women and 38 men; median age 66 years) with recurrent and/or clinically apparent, cutaneous or subcutaneous melanoma metastases in an extremity. Radionuclide monitoring was performed with continuous, precordial count rate determinations of an intravascular (99m) Tc-labelled tracer infused into the isolated limb circulation. RESULTS: One hundred and sixteen of 131 procedures were completed. In 13%, a leakage of ≥10% was detected; in 6% (n = 8), the cytotoxic drug was never infused because of constant leakage; in 7% (n = 9), leakage ≥10% was measured during the perfusion resulting in two perfusions being terminated before 30 min, 5 perfusions were considered completed though with early termination (after 30 min, before 60 min), and 2 fully completed. No patients had systemic toxicity requiring treatment, whereas considerable or serious local toxicity were observed in 14%. Three of the patients with leakage ≥10% were successfully treated in a repeated procedure. CONCLUSION: Leakage monitoring using a threshold of 10% during ILP saves the patients from systemic toxicity, however, at the expense of early termination or cancellation of ILP treatment in a few patients and repeated ILP procedures in some.

Non-invasive imaging for subclinical coronary atherosclerosis in patients with peripheral artery disease.

Patients with peripheral artery disease are at high risk of coronary artery disease. An increasing number of studies show that a large proportion of patients with peripheral artery disease have significant coronary atherosclerosis, even in the absence of symptoms. Although the reported prevalence of subclinical coronary artery disease varies widely in patients with peripheral artery disease, it could include more than half of patients. No consensus exists to date on either the rationale for screening patients with peripheral artery disease for coronary atherosclerosis or the optimal algorithm and method for screening. An increasing number of imaging modalities are emerging that allow improved in vivo non-invasive characterization of atherosclerotic plaques. These novel imaging methods may lead to early detection of high-risk vulnerable plaques, enabling clinicians to improve risk stratification of patients with peripheral artery disease, and thus paving the way for individualized therapy.

Tumour response after hyperthermic isolated limb perfusion for locally advanced melanoma.

INTRODUCTION: The aim was to describe tumour response, complications, recurrence and survival after hyperthermic isolated limb perfusion (ILP) with melphalan or melphalan in combination with tumour necrosis factor-alpha in patients with melanoma metastases confined to an extremity. MATERIAL AND METHODS: A total of 84 perfusions were performed (53 women, 31 men, median age 63 years) from 1993 to 2010. 95% of the perfusions were administered to the lower limbs and 5% to the upper limbs. The inclusion criteria were recurrent and/or clinically apparent cutaneous/subcutaneous extremity in-transit melanoma metastases. RESULTS: The response rate after ILP was 85%; 42% had complete response (CR), 43% partial response (PR), 12% no change (NC) and 3% progression. Two- and five-year survival rates were 57% and 31%, respectively, and they were higher for patients with than without lymph node metastases. Time from ILP to recurrence was a median of seven months (range 1-37 months) for patients with CR or PR. Survival was longer for patients with CR or PR than for patients showing NC or progression. Several patients had mild or moderate local toxicity reactions, two patients developed severe local toxicity. CONCLUSION: ILP induces tumour regression in the vast majority of patients. One patient, i.e. 1% of the group, died from surgical complications. Otherwise, ILP treatment had an acceptable morbidity in this group of very sick patients. We are convinced that the treatment should be offered to improve local disease control in patients with multiple and/or recurrent melanoma confined to an extremity if surgical excision is not possible. FUNDING: not relevant. TRIAL REGISTRATION: not relevant.

Can preoperative myocardial perfusion scintigraphy predict changes in left ventricular perfusion and function after coronary artery bypass graft surgery?

OBJECTIVES We wanted to evaluate whether preoperative myocardial perfusion scintigraphy (MPS) could predict changes in cardiac symptoms and postoperative myocardial perfusion and left ventricular function after coronary artery bypass grafting (CABG). METHODS Ninety-two patients with stable angina pectoris (and at least one occluded coronary artery) underwent MPS before, and 6 months after, undergoing CABG. The result of the MPS was kept secret from the surgeons. RESULTS Before CABG, 90% of the patients had angina. After CABG, 97% of the patients were without symptoms. Overall graft patency was 84%. Before CABG, one patient had normal perfusion; in the rest of them the defects were classified as follows: reversible (60%), partly reversible (27%) and irreversible (12%). Following CABG, 33% had normal perfusion; in the rest the defects were reversible in 29%, partly reversible in 12% and irreversible in 26%. Left ventricular ejection fraction (LVEF), which was normal before operation in 45%, improved in 40% of all patients. The increase in LVEF was not related to the preoperative pattern of perfusion defects. Of 30 patients with normalized perfusion after CABG, 29 (97%) had reversible defects and one patient had partly reversible defects. Of 83 perfusion defects, which were normalized after CABG, 67 were reversible (81%) or partly reversible (12%). Seventy-five percent of all reversible coronary artery territories before CABG were normalized after operation. CONCLUSIONS Our results indicate that reversible or partly reversible perfusion defects at a preoperative MPS have a high chance of normalized myocardial perfusion assessed by MPS 6 months after operation. Normal perfusion is obtained almost exclusively in territories with reversible ischaemia. Symptoms improved in nearly all patients and LVEF in a significant fraction of the patients, not related to preoperative MPS.

(111)Indium Labelling of Recombinant Activated Coagulation Factor VII: In Vitro and Preliminary In Vivo Studies in Healthy Rats.

The aim of this study is to investigate whether (111)Indium-labelled recombinant FVIIa (rFVIIa) could be a potential radiopharmaceutical for localization of bleeding sources. DTPA-conjugated rFVIIa was radiolabelled with (111)In chloride. In vitro binding efficiency of (111)In-DTPA-rFVIIa to F1A2-Mab-sepharose was 99% in buffer, while it was 88-82% in serum. The binding efficiency of (111)In-DTPA-rFVIIa to TF (1-209)-sepharose was 48% in buffer whereas 39%-36% in serum, respectively. In vivo experiment was conducted in healthy rats, and gamma camera images were taken immediately after iv. administration of 1.6-1.8 MBq (111)In-DTPA-rFVIIa up to 120-130 min. Five min after administration of (111)In-DTPA-rFVIIa, percentage of (111)In activity was 6.0% in the cardiac region and 24.5% in the liver region. After 2 hours activity was decreased to 3.3% in heart while it had increased to 42.0% in the liver. The (111)In-DTPA-rFVIIa might be a potential radiopharmaceutical for visualisation of tissues with significant TF expression such as acute bleeding lesions in the gastrointestinal tract.

Atrial Natriuretic Peptide and Acute Changes in Central Blood Volume by Hyperthermia in Healthy Humans.

BACKGROUND: Hyperthermia induces vasodilatation that reduces central blood volume (CBV), central venous pressure (CVP) and mean arterial pressure (MAP). Inhibition of atrial natriuretic peptide (ANP) could be a relevant homeostatic defense mechanism during hyperthermia with a decrease in CBV. The present study evaluated how changes in plasma ANP reflect the changes in CBV during hyperthermia. METHODS: Ten healthy subjects provided with a water perfused body suit increased body core temperature 1 °C. In situ labeled autologous red blood cells were used to measure the CBV with a gamma camera. Regions of interest were traced manually on the images of the whole body blood pool scans. Two measures of CBV were used: Heart/whole body ratio and thorax/whole body ratio. CVP and MAP were recorded. Arterial (ANPart) and venous plasma ANP were determined by radioimmunoassay. RESULTS: The ratio thorax/whole body and heart/whole body decreased 7 % and 11 %, respectively (p<0.001). MAP and CVP decreased during hyperthermia by 6.8 and 5.0 mmHg, respectively (p<0.05; p<0.001). Changes in both thorax/whole body (R=0.80; p<0.01) and heart/whole body ratios (R=0.78; p<0.01) were correlated with changes in ANPart. However, there was no correlation between venous ANP and changes in CBV, nor between ANPart and MAP or CVP. CONCLUSION: Arterial but not venous plasma concentration of ANP, is correlated to changes in CBV, but not to pressures. We suggest that plasma ANPart may be used as a surrogate marker of acute CBV changes.

Easy and efficient (111)indium labeling of long-term stored DTPA conjugated protein.

UNLABELLED: The labelling efficiency of long-term stored DTPA-conjugates has not been reported previously even though DTPA has been in extensive use as metal chelator in the development of radiopharmaceuticals and contrast agents. DTPA is often used as a bifunctional chelating agent conjugated to tumor targeting vehicles such as monoclonal antibodies and receptor directed peptides. The purpose of this study was to monitor the labelling efficiency of a DTPA-conjugate on long-term storage using 111In-chloride at two different temperatures and incubation times for the In-labelling. METHOD: Cyclic-diethylene-triamine-pentaacetic acid (cDTAP) was conjugated to a polyclonal immunoglobulin-G (IgG) in borate buffer, pH 8.2 at +4?C for 4 hours. Then the DTPA-conjugate was dialyzed against 50 mmol/l sodium citrate buffer saline, pH 6.0 and stored at -80° C in aliquots of 1 mg/0.5 ml. The DTPA-conjugate was labeled with 111In-chloride in citrate buffer, pH 6. The labelling reaction was incubated at room temperature (RT) for 30 min and at +4?C for 90 min. Determination of labelling efficiency was performed using ITLC and an instant chromatography scanner equipped with a NaI crystal. The labelling efficiency of the DTPA-conjugate was monitored every third month for 12 months. RESULTS: The median labelling efficiencies varied between 92 and 96% during the whole period. The two combinations of incubation times and temperatures (30 min at RT and 90 min at +4°C) had no affect on labelling efficiency of the DTPA-conjugate, stored for 12 months. CONCLUSION: Our study shows that 111In-labelling can easily be performed within 30 min at RT for thermo-stable proteins like polyclonal, DTPA-conjugated IgG stored long-term at -80°C with a high 111In-labelling efficiency.

The diagnostic value of adding dynamic scintigraphy to standard delayed planar imaging for sentinel node identification in melanoma patients.

PURPOSE: The aim of this study was to compare early dynamic imaging combined with delayed static imaging and single photon emission computed tomography (SPECT)/CT with delayed, planar, static imaging alone for sentinel node (SN) identification in melanoma patients. METHODS: Three hundred and seven consecutive melanoma patients referred for SN biopsy (SNB) were examined using combined imaging. Secondary interpretation of only the delayed static images was subsequently performed. In 220 patients (72%), complete surgical and pathological information relating to the SNB was available. The number of SNs identified and number of patients with positive SNs were compared between the two interpretations of the imaging studies and, when available, related to pathology data. RESULTS: A slightly higher number of SNs (mean 0.12/patient) was identified when interpreting only delayed static images compared to combined imaging. In a direct patient-to-patient comparison, the number of SN(s) identified on the combined vs static images only showed moderate agreement (kappa value 0.56). In 38 patients (17%), positive SNs were identified by the combined procedure compared to 35 (16%) by static imaging only. Thus by static imaging only, tumour-positive SNs were not identified in 3 of 38 patients (8%). CONCLUSION: For SN identification in melanoma patients, dynamic imaging combined with delayed static imaging and SPECT/CT is superior to delayed static imaging only because the latter is more likely to fail to identify SNs containing metastases.

Angiography-based prediction of outcome after coronary artery bypass surgery versus changes in myocardial perfusion scintigraphy.

OBJECTIVES: The present study compared the clinical prediction of the effect of coronary artery bypass grafting (CABG) on coronary blood flow and left ventricular ejection fraction (LVEF) with changes in gated myocardial perfusion scintigraphy. METHODS: A prospective group of 92 patients underwent myocardial perfusion scintigraphy before and 6 months after CABG, the results being kept secret from the surgeon. Based on clinical and angiographic findings, the surgeons filled in a questionnaire indicating the predicted changes in coronary blood flow in each of the three coronary artery territories and in the LVEF. RESULTS: Symptomatic improvement was present in nearly all the patients. Following CABG, the perfusion defects were reduced in around two-thirds and normalized in one-third of the territories clinically predicted to improve. Improved perfusion for territories not predicted to improve was slightly lower, and correlations between predicted and observed regional changes in coronary blood flow and perfusion defects were poor. LVEF increased (by over five ejection fraction units) in almost half of the patients, but with no correlation between the predicted and the observed changes. CONCLUSIONS: Based on clinical and angiographic findings, the marked improvements after CABG in cardiac perfusion and function are poorly predicted.

Axillary sentinel node identification in breast cancer patients: degree of radioactivity present at biopsy is critical.

BACKGROUND: The radioactivity present in the patient (Act(rem) ) at sentinel node (SN) biopsy will depend on injected activity amount as well as on the time interval from tracer injection to biopsy, which both show great variations in the literature. The purpose of this study was to analyse the influence of varying Act(rem) levels on the outcome of axillary SN biopsy in patients with breast cancer (BC). MATERIAL AND METHODS: Eight hundred and fifty-eight patients with BC were consecutively referred to SN biopsy, 21% for a same-day and 79% of the patients for a 2-day procedure. Four hundred and nineteen patients underwent scintigraphy and 439 did not. For same-day procedures, 50 MBq (99m) Tc-nanocolloid (Nanocoll(®) ) was injected, and for 2-day procedures 110 MBq. For the analysis of SN biopsy outcome, the patients were divided into three Act(rem) groups: <10 (56% of the patients), 10-20 (23%), and >20 MBq (21%). During surgery, SNs were located using a hand-held gamma probe supported by image information when available and blue dye injection. Pathology included haematoxylin-eosin staining followed by immunohistochemistry. RESULTS: The number of SNs removed (mean value 1·87 versus 2·14, P = 0·0003) and the probability of finding a malignant SN (P = 0·034) were lower in the <10 MBq group of patients compared with higher Act(rem) >20 MBq. Of the 25 patients with SN non-detection, 20 patients had an Act(rem) <10 MBq. Imaging had no significant influence on the number of patients with a malignant SN (P = 0·48). CONCLUSION: Act(rem) above 10 MBq for nanocolloid tracer appears important for appropriate identification of SNs in patients with BC.

Mesenchymal stromal cell derived endothelial progenitor treatment in patients with refractory angina.

AIMS: We evaluated the feasibility, safety and efficacy of intra-myocardial injection of autologous mesenchymal stromal cells derived endothelial progenitor cell (MSC) in patients with stable coronary artery disease (CAD) and refractory angina in this first in man trial. METHODS AND RESULTS: A total of 31 patients with stable CAD, moderate to severe angina and no further revascularization options, were included. Bone marrow MSC were isolated and culture expanded for 6-8 weeks. It was feasible and safe to establish in-hospital culture expansion of autologous MSC and perform intra-myocardial injection of MSC. After six months follow-up myocardial perfusion was unaltered, but the patients increased exercise capacity (p < 0.001), reduction in CCS Class (p < 0.001), angina attacks (p < 0.001) and nitroglycerin consumption (p < 0.001), and improved Seattle Angina Questionnaire (SAQ) evaluations (p < 0.001). For all parameters there was a tendency towards improved outcome with increasing numbers of cells injected. In the MRI substudy: ejection fraction (p < 0.001), systolic wall thickness (p = 0.03) and wall thickening (p = 0.03) all improved. CONCLUSIONS: The study demonstrated that it was safe to treat patients with stable CAD with autologous culture expanded MSC. Moreover, MSC treated patients had significant improvement in left ventricular function and exercise capacity, in addition to an improvement in clinical symptoms and SAQ evaluations.

Exanthema after a stress Tc-99m sestamibi study: continue with a rest sestamibi study?

PURPOSE: A mild allergic reaction assumed to be caused by injection of Tc-99m sestamibi for a stress myocardial perfusion imaging (MPI) is presented. We want to discuss the risk involved in completing the MPI with another sestamibi injection, and the precautions and possible treatment in case of a further reaction. MATERIAL AND METHODS: A patient experienced a maculo-papular exanthema, i.e. a mild, probably allergic, adverse event (AE) after a stress MPI including administration of a dose of Tc-99m sestamibi. A rest MPI was needed to decide whether coronary bypass surgery should be performed. After prophylactic treatment with antihistamine and corticosteroid, an uneventful rest MPI was performed. DISCUSSION AND CONCLUSION: International recommendations or guidelines related to treatment of AEs after nuclear medicine studies do not exist. Serious AEs in nuclear medicine are very rare, but anaphylactic reactions have been reported and may be life threatening. If repeated administration of the radio-pharmaceutical must be given, the prophylactic and therapeutic interventions should follow general international guidelines for allergic reactions.

Hybrid cardiac imaging: SPECT/CT and PET/CT. A joint position statement by the European Association of Nuclear Medicine (EANM), the European Society of Cardiac Radiology (ESCR) and the European Council of Nuclear Cardiology (ECNC).

Improvements in software and hardware have enabled the integration of dual imaging modalities into hybrid systems, which allow combined acquisition of the different data sets. Integration of positron emission tomography (PET) and computed tomography (CT) scanners into PET/CT systems has shown improvement in the management of patients with cancer over stand-alone acquired CT and PET images. Hybrid cardiac imaging either with single photon emission computed tomography (SPECT) or PET combined with CT depicts cardiac and vascular anatomical abnormalities and their physiologic consequences in a single setting and appears to offer superior information compared with either stand-alone or side-by-side interpretation of the data sets in patients with known or suspected coronary artery disease (CAD). Hybrid systems are also advantageous for the patient because of the single short dual data acquisition. However, hybrid cardiac imaging has also generated controversy with regard to which patients should undergo such integrated examination for clinical effectiveness and minimization of costs and radiation dose, and if software-based fusion of images obtained separately would be a useful alternative. The European Association of Nuclear Medicine (EANM), the European Society of Cardiac Radiology (ESCR) and the European Council of Nuclear Cardiology (ECNC) in this paper want to present a position statement of the institutions on the current roles of SPECT/CT and PET/CT hybrid cardiac imaging in patients with known or suspected CAD.

Serial in vivo imaging of the porcine heart after percutaneous, intramyocardially injected 111In-labeled human mesenchymal stromal cells.

This pilot trial aimed to investigate the utilization of (111)In-labeling of mesenchymal stromal cells (MSC) for in vivo tracking after intramyocardial transplantation in a xenotransplantation model with gender mismatched cells. Human male MSC were expanded ex vivo and labeled with (111)In-tropolone. Ten female pigs were included. The labeled cells were transplanted intramyocardially using a percutaneous injection system. The (111)In activity was determined using gamma camera imaging. Excised hearts were analyzed by fluorescence in situ hybridization (FISH) and microscopy. Gamma camera imaging revealed focal cardiac (111)In accumulations up to 6 days after injection (N = 4). No MSC could be identified with FISH, and microscopy identified widespread acute inflammation. Focal (111)In accumulation, inflammation but no human MSC were similarly seen in pigs (N = 2) after immunosuppression. A comparable retention of (111)In activity was observed after intramyocardial injection of (111)In-tropolone (without cells) (N = 2), but without sign of myocardial inflammation. Injection of labeled non-viable cells (N = 1) also led to high focal (111)In activity up to 6 days after intramyocardial injection. As a positive control of the FISH method, we identified labeled cells both in culture and immediately after cell injection in one pig. This pilot trial suggests that after intramyocardial injection (111)In stays in the myocardium despite possible disappearance of labeled cells. This questions the clinical use of (111)In-labeled cells for tracking. The results further suggest that xenografting of human MSC into porcine hearts leads to inflammation contradicting previous studies implying a special immunoprivileged status for MSC.