Comparative study of 18F-FDG PET/CT and CT angiography in detection of large vessel vasculitis. / Estudio comparativo de la PET/TC con 18F-FDG y la angiografía por TC en la detección de la vasculitis de grandes vasos.

OBJECTIVE: Compare 18F-FDG PET/CT and CTangio in the diagnosis of extracraneal large vessel involvement in patients with suspicion of large vessel vasculitis (LVV). MATERIAL AND METHODS: A retrospective database reviewed 59 patients with clinical suspicion of LVV undergoing 18F-FDG PET/CT and CTangio. In 55 patients PET/TC and CTangio were done simultaneously in the same machine and in 4 patients with a scan interval of<1 month. PET/CT analyses included qualitatively and quantitative analysis (ratio SUVmax 18F-FDG vessel/SUVmax liver). CTangio was assessed for concentric mural thickening, contrast wall enhancement and structural vascular changes as potential complications of vasculitis. RESULTS: 18F-FDG PET/CT and CTangio show high specificity (97.2%) for LVV diagnosis, with an excellent sensitivity for 18F-FDG PET/CT (95.6%) and lower for CTangio (60.9%), which leads to a high negative predictive value for 18F-FDG PET/CT (97.2%) and a high false negative rate for CTangio (39.1%). A 70% concordance between 18F-FDG PET/CT and CTangio was obtained (Kappa index 0.70± 0.095 (P<.001). CONCLUSION: The results show the greater potential of 18F-FDG PET/CT for the detection and extension of LVV. Therefore, 18F-FDG PET/CT should be exploited to the maximum and consider as the first line imaging technique in the extracranial diagnosis of LVV and its possible association with polymyalgia rheumatica. The addition of CTangio could be more indicated in patients with Takayasu arteritis and in long-standing and/or severe vasculitis since it increases the accuracy in the detection of possible vascular complications.

Calcifilaxis: una causa poco común de acumulación de fosfonatos en partes blandas / Calciphylaxis: a rare cause of accumulation of phosphonates in soft tissues

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[Sympathetic reinnervation of the transplanted heart. Study using iodine-123 labeled meta-iodobenzylguanidine]. / Reinervación simpática del corazón trasplantado. Estudio realizado con metayodobenzilguanidina marcada con yodo-123.

INTRODUCTION AND OBJECTIVES: Metaiodobenzylguanidine (MIBG) is an analogue of norepinephrine and its cardiac uptake shows sympathetic innervation. During the heart transplantation the allograft becomes completely denervated. The present study was conducted to assess the evolution of sympathetic re-innervation after transplantation, and to related re-innervation with functional status. PATIENTS AND METHODS: We studied 31 patients from 6 months to 12 years after transplantation by 123I-MIBG studies to evaluate re-innervation and by rest/exercise radionuclide ventriculography to evaluate cardiac function. Myocardial MIBG uptake was quantified by calculating a heart-to-mediastinum ratio (HMR). An HMR > 1.8 was considered normal, moderate between 1.8 and 1.6, mild between 1.6 and 1.3, and absent < 1.3. RESULTS: HMR correlated with time after transplantation (r = 0.607; p < 0.001). HMR of patients studied after 2 years of transplantation was significantly higher (1.62 +/- 0.2 vs 1.34 +/- 0.2; p < 0.05). MIBG uptake was in the anterior region in 3 patients, in the antero-lateral region in 25, and in the antero-lateral and septal regions in 3. From a functional point of view, peak filling rate at exercise was higher in patients studied 2 years after the transplantation (2.7 +/- 0.8 edv/s vs 2.16 +/- 0.5 edv/s; p = 0.02). These patients also showed a higher increase of heart rate with exercise (p < 0.005 vs p < 0.01). CONCLUSIONS: Sympathetic re-innervation increase with time after heart transplantation, and is more frequently seen 2 years after transplantation. Sympathetic re-innervation first appears in the anterior or the antero-lateral regions. A complete re-innervation of the transplanted heart does not occur 12 years after transplantation.

[Evaluation of myocardial viability using perfusion cardiac SPECT. 201-thallium rest/redistribution, 201-thallium rest/reinjection and technetium 99m tetrofosmin rest/postnitrates]. / Valoración de la viabilidad miocárdica mediante SPET cardíaco de perfusión. Talio-201 reposo/redistribución, talio-201 reposo/reinyección y tecnecio-99m tetrofosmina reposo/posnitratos.

INTRODUCTION AND OBJECTIVES: It has been demonstrated that nitrate administration enhances the detection of myocardial viability in thallium-201 and technetium-99m sestamibi myocardial perfusion studies. The aim of this study was to assess the influence of nitrate administration on technetium-99m tetrofosmin myocardial uptake in patients with coronary artery disease and left ventricular dysfunction. PATIENTS AND METHODS: Twenty eight patients with coronary artery disease, previous myocardial infarction and left ventricular ejection fraction < 40% underwent, within 48 hours, rest/postnitroglycerin (0.4 mg sublingually) technetium-99m tetrofosmin single photon emission tomography (SPET), comparing these results with that of thallium-201 rest/redistribution SPET in 13 patients (first group) and with that of thallium-201 rest/reinjection SPET in the other 15 patients (second group). Tomograms based on the 3 spatial planes were divided into 15 segments and regional tracer uptake was quantitatively analysed. Viability was defined as presence of tracer uptake > or = 50% of peak activity. RESULTS: The percentage of peak activity at rest or after nitrate administration of technetium-99m tetrofosmin correlated, with that of thallium-201, at rest and after redistribution or reinjection (r = 0.8; p < 0.001). On resting technetium-99m tetrofosmin studies 167 of the 420 segments that were analysed had < 50% of peak activity. 14.5% of these segments showed reversibility after nitrate administration, with an increase in 99mTc-tetrofosmin uptake from 45 +/- 5% to 55 +/- 4% of peak activity (p = 0.001), in the first group, and from 40 +/- 9% to 57 +/- 9% of peak activity (p = 0.003), in the second group. Overall agreement between rest/postnitroglycerin technetium-99m tetrofosmin SPET studies and rest/redistribution or rest/reinjection thallium-201 SPET studies, regarding the presence of myocardial viability, was 87% and 90%, respectively. All except one reversible segments on tetrofosmin studies after nitrates had viability criteria on thallium studies. CONCLUSIONS: Nitrate administration at rest enhances the detection of myocardial viability using technetium-99m tetrofosmin SPET, correlating with viability criteria observed on thallium studies. It represents a simple and useful technique in the assessment of myocardial viability.

[Functional dyspepsia, gastric emptying of solids, and Helicobacter pylori infection]. / Dispepsia funcional, vaciado gástrico de sólidos e infección por Helicobacter pylori.

UNLABELLED: The origin of functional dyspepsia (FD) is unknown, however, abnormal gastric emptying and infection by H. pylori have been suggested as possible causes. OBJECTIVE: The aim of this study was to test the hypothesis that infection by H. pylori could be related to alterations in gastric emptying of solids and play a role in the pathophysiology of dyspepsia. METHODS: Studies were performed on 12 controls: 6 males, 6 females, age 40 +/- 13, and on 45 FD patients: 15 males and 30 females, age 43.5 +/- 12. Clinical criteria for FD diagnosis were post-prandial epigastric pain, nausea, vomiting or epigastric bloating, with normal blood test, upper endoscopy and abdominal ultrasound. Diagnosis of H. pylori infection was either by growth positive on culture of antral biopsy or by all of the following: on Gram stain, urease test positive and visualization of microorganisms in the antral biopsy. Gastric emptying of solids was studied with a radio-nuclide technique. Patients were prospectively classified in 4 groups according to the main symptom: reflux-like, ulcer-like, dysmotility, and non-specific. RESULTS: H. pylori infection was observed in 21/32 (66%) FD patients. No significant differences in the gastric emptying of solids between the control group and patients with FD (tl/2 80 +/- 17 minutes vs 75 +/- 16 min). The presence of H. pylori infection did not influence gastric emptying rates (78 +/- 16 minutes in infected patients vs 73 +/- 15 min in non infected patients). Gastric emptying times were similar among the four subgroups of FD patients. CONCLUSIONS: No significant differences in gastric emptying of solids were found in H. pylori infected persons as compared with the controls. These findings suggest that H. pylori infection and/or changes in gastric emptying of solids do not play a role in the pathophysiology of FD.

Early postoperative reduction of monoclonal antimyosin antibody uptake is associated with absent rejection-related complications after heart transplantation.

BACKGROUND: Detection and treatment for rejection after transplantation are based on the identification of myocyte damage upon endomyocardial biopsy. Noninvasive detection of such damage is possible with 111In-labeled monoclonal antimyosin antibodies (MAA). Although the presence and degree of MAA uptake parallels the rejection activity detected by biopsy, the relation between the degree of uptake and the occurrence of severe rejection-related complications has not been previously assessed. METHODS AND RESULTS: Two hundred forty-seven MAA studies were performed coinciding with biopsies in 52 patients 1-71 months after transplantation. A heart-to-lung ratio (HLR) was used as a measure of relative MAA uptake, with an HLR of 1.55 discriminating normal from abnormal studies. Of the 247 antimyosin studies, 149 coincided with absent, 38 with mild, and 60 with moderate rejection at biopsy. HLR was 1.68 +/- 0.27, 1.79 +/- 0.22, and 1.91 +/- 0.33 in the three biopsy groups, respectively (p less than 0.0001). Two hundred thirty-eight of 247 antimyosin studies coexisted with absent rejection-related complications; in nine of 247 patients, such complications were detected (five congestive heart failure episodes due to rejection and four episodes of vascular occlusion, which resulted in five deaths), and mean HLR was 1.74 +/- 0.3 and 2.1 +/- 0.16 in the two groups, respectively (p less than 0.0001). No complications were noted in 193 studies of patients with HLR of less than 2.00, whereas in nine of 45 with HRL of 2.00 or greater, complications occurred (p less than 0.0001). None of the 23 patients prospectively followed since surgery who had a gradual decrease in MAA uptake during the first 3 months showed rejection-related complications, whereas persistent uptake was associated with complications in five of nine patients (p less than 0.001). CONCLUSIONS: No rejection-related complications are seen coinciding with HLR of less than 2.00, whereas patients who have complications have an HLR of more than 2.00. The early 3-month pattern of decreasing MAA uptake is associated with a clinical course free of rejection-related complications, whereas a persistent pattern is a signal of the possibility of such complications.

Patterns of evolution of myocyte damage after human heart transplantation detected by indium-111 monoclonal antimyosin.

The indium-111 labeled Fab fragment of antimyosin monoclonal antibody was used to study cardiac rejection and the time course of myocyte damage after transplantation. Fifty-three studies were performed in 21 patients, 17 men and 4 women, aged 19 to 54 years (mean 37 +/- 8), from 7 to 40 months after transplantation. Repeat studies were available in 8, and 10 were studied after the first year of transplantation. A heart-to-lung ratio was used for quantitation of uptake (normal 1.46 +/- 0.04). Differences between absent (1.69 +/- 0.29) and moderate (1.90 +/- 0.36) rejection were significant (p less than 0.03). Antimyosin ratio at 1 to 3 months (1.89 +/- 0.35) differed from that at greater than 12 months (1.65 +/- 0.2) (p less than 0.01). Repeat studies revealed a decrease in antimyosin ratio in 5 patients with uneventful clinical course; 2 had persistent activity after transplantation and suffered heart failure from rejection. After 1 year of transplantation uptake was within normal limits in 7 of 10 patients, and high uptake was associated with vascular rejection in 1. Because they can define evolving patterns of myocardial lesion activity, antimyosin studies could be useful both in patient management and in concentrating resources for those patients who most require them. The heart-to-lung ratio is suggested to monitor sequentially the degree of myocyte damage after transplantation.