Description of a different quantification method for amyloid burden (DPDload) and validation of SPECT/CT in cardiac amyloidosis.

BACKGROUND: Bone tracers such as 99mTc-DPD have shown high sensitivity and specificity in the non-invasive diagnosis of transthyretin cardiac amyloidosis (ATTR-CA). This study aims to validate SPECT/CT and assess the usefulness of uptake quantification (DPDload) in the myocardial tissue as potential information on the amyloid burden. METHODS: In a retrospective analysis of 46 patients with suspected CA, 23 cases with ATTR-CA had two quantification methods conducted to estimate amyloid burden (DPDload) through planar scintigraphic scans and a SPECT/CT. RESULTS: SPECT/CT significantly provided an added value in the patient's diagnosis with CA (P<.05). The estimation of the amyloid burden substantiated that the most affected wall of the LV is the interventricular septum in most cases and the existence of a significant relationship between the Perugini score uptake and the DPDload. CONCLUSIONS: We validate the need for SPECT/CT to complement planar imaging in diagnosing ATTR-CA. For its part, quantifying the amyloid load continues to be a complex area of research. It requires further studies with a larger number of patients to validate a standardized method of amyloid load quantification, both for diagnosis and treatment monitoring.

Enhanced quantitative method for the diagnosis of grade 1 cardiac amyloidosis in 99mTc-DPD scintigraphy.

The lack of a standardized cut-off value in the quantitative method and an inter-observer disagreement in the evaluation of the semiquantitative score in 99mTc-DPD scintigraphy leaves several patients with cardiac amyloidosis (CA) undiagnosed (grade 1 and H/CL: 1-1.49). This study aims to increase diagnostic productivity of 99mTc-DPD scintigraphy in CA. This is a retrospective study of 170 patients with suspicion of CA. A total of 81 (47.6%) were classified as transthyretin CA (TTR-CA) and 9 (5.3%) as light-chain CA (LC-CA) applying the visual score. An enhanced quantitative method and cut-off point were attempted to reclassify inconclusive patients and reduce inter-observer variability. Applying the proposed quantitative method, of the 19 patients with grade 1 uptake, 2 became grade 0 (none-CA), 2 were reclassified as grade 3 (TTR-CA), and 2 were regrouped as grade 2 (1 TTR-CA and 1 LC-CA). Adjusting the quantitative method's cut-off value to 1.3, four patients previously inconclusive were reclassified as TTR-CA, the diagnosis was confirmed in 3 and rejected in 1. When a 1.3 threshold is compared to 1.5, the sensitivity increases to 94% without reducing its specificity. The quantitative method improves the visual interpretation, reclassifying doubtful cases. The optimization of the cut-off value from 1.5 to 1.3 reclassifies a higher percentage of patients as TTR-CA with a higher sensitivity without reducing its specificity.

Added-value of molecular imaging in myocardial metastasis of an ileal neuroendocrine tumour treated with peptide receptor radionuclide therapy: a case report.

BACKGROUND: Neuroendocrine tumours (NET) conform a rare type of neoplasm, mostly located in the gastrointestinal tract. They are slow-growing tumours, so at the time of the diagnosis, most patients present with metastatic lesions, mainly in the liver. The myocardium is a rare and important organ for metastasis, in which 68Ga-Dotatate positron emission tomography-computed tomography (PET/CT) shows a high diagnostic sensitivity for its detection, contrary to carcinoid valve disease, where anatomic imaging plays a key role, especially the echocardiogram. CASE SUMMARY: A 60-year-old man diagnosed with metastatic progressive ileal NET, who underwent a 68Ga-Dotatate PET/CT prior 177Lu-Dotatate therapy, showed a metastatic lesion in the left ventricle that was undetected in previous studies, such as an Octreoscan® and CT. A transthoracic echocardiogram was performed revealing the existence of a second cardiac lesion, a tricuspid valve carcinoid disease. A cardiac magnetic resonance showed no late gadolinium enhancement. DISCUSSION: The 68Ga-Dotatate PET/CT is currently considered the gold standard for assessment and follow-up of NET, including those with rare sites of metastasis such as cardiac infiltration. In this case, it stimulated the persue of possible cardiac involvement, detecting the coexistence of two types of lesions (cardiac metastasis and carcinoid valve disease). Of these, carcinoid valvulopathy develops in 50% of NET cases, while cardiac metastasis (CM) is less frequent (only 5%).

Evaluation of 177Lu-Dotatate treatment in patients with metastatic neuroendocrine tumors and prognostic factors.

BACKGROUND: 177Lu peptide receptor radionuclide therapy (PRRT) is a recently approved therapy in Spain that has been demonstrated to be a well-tolerated therapy for positive somatostatin receptor advanced gastroenteropancreatic neuroendocrine tumors. AIM: To determine the impact of PRRT on quality of life, radiologic and metabolic response, overall survival, prognostic factors and toxicity. METHODS: Thirty-six patients treated with 177Lu-PRRT from 2016 to 2019 were included. The most frequent location of the primary tumor was the gastrointestinal tract (52.8%), pancreas (27.8%), and nongastropancreatic neuroendocrine tumor (11.1%). The liver was the most common site of metastasis (91.7%), followed by distant nodes (50.0%), bone (27.8%), peritoneum (25.0%) and lung (11.1%). Toxicity was evaluated after the administration of each dose. Treatment efficacy was evaluated by two parameters: stable disease and disease progression in response evaluation criteria in solid tumors 1.1 criterion and prognostic factors were tested. RESULTS: From 36 patients, 55.6% were men, with a median age of 61.1 ± 11.8 years. Regarding previous treatments, 55.6% of patients underwent surgery of the primary tumor, 100% of patients were treated with long-acting somatostatin analogues, 66.7% of patients were treated with everolimus, 27.8% of patients were treated with tyrosine kinase inhibitor, and 27.8% of patients were treated with interferon. One patient received radioembolization, three patients received chemoembolization, six patients received chemotherapy. Hematological toxicity was registered in 14 patients (G1-G2: 55.5% and G3: 3.1%). Other events presented were intestinal suboclusion in 4 cases, cholestasis in 2 cases and carcinoid crisis in 1 case. The median follow-up time was 3 years. Currently, 24 patients completed treatment. Nineteen are alive with stable disease, two have disease progression, eight have died, and nine are still receiving treatment. The median overall survival was 12.5 mo (95% confidence interval range: 9.8-15.2), being inversely proportional to toxicity in previous treatments (P < 0.02), tumor grade (P < 0.01) and the presence of bone lesions (P = 0.009) and directly proportional with matching lesion findings between Octreoscan and computed tomography pre-PRRT (P < 0.01), , primary tumor surgery (P = 0.03) and metastasis surgery (P = 0.045). In a multivariate Cox regression analysis, a high Ki67 index (P = 0.003), a mismatch in the lesion findings between Octreoscan and computed tomography pre-PRRT (P < 0.01) and a preceding toxicity in previous treatments (P < 0.05) were risk factors to overall survival. CONCLUSION: Overall survival was inversely proportional to previous toxicity, tumor grade and the presence of bone metastasis and directly proportional to matching lesion findings between Octreoscan and computed tomography pre-PRRT and primary tumor and metastasis surgery.

Advantages and limitations of 18-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography in the diagnosis of infective endocarditis.

INTRODUCTION: The early diagnosis of infective endocarditis (IE) is a medical challenge and a multidisciplinary approach is essential to improve its frequently fatal prognosis. Our goal was to evaluate the usefulness of [18F]2-fluoro-2-deoxy-d-glucose positron emission tomography (18F-FDG PET) in the diagnosis of this disease. MATERIALS AND METHODS: We prospectively assessed 43 patients (five female and 38 male) with clinical suspicion of IE between 2014 and 2017. All patients underwent transesophageal echocardiography (TEE) and an 18F-FDG PET scan, and the results were compared. A positive PET finding was defined as increased FDG uptake on cardiac valves or intracardiac devices. RESULTS: Out of 43 patients with suspected IE, the diagnosis was confirmed in 30 cases (79.7%). 18F-FDG PET was positive in 24 patients, with 19 showing FDG uptake on cardiac valves (two native and 17 prosthetic) and five on cardiac devices, being concordant with echocardiographic findings in 11 cases. 18F-FDG PET sensitivity was 80%, specificity 92%, positive predictive value (PPV) 96% and negative predictive value (NPV) 66%. Echocardiography presented sensitivity, specificity, PPV and NPV of 36%, 84%, 84% and 36%, respectively. CONCLUSIONS: 18F-FDG PET proved to be a sensitive technique with a high diagnostic value in patients with prosthetic valves and intracardiac devices and suspected IE. Its utility decreased dramatically in patients with suspected IE on native valves, in which TEE presented higher sensitivity and thus better diagnostic value.