Lung scintigraphy in the diagnosis of pulmonary embolism: current methods and interpretation criteria in clinical practice

BACKGROUND: In current clinical practice lung scintigraphy is mainly used to exclude pulmonary embolism (PE). Modified diagnostic criteria for planar lung scintigraphy are considered, as newer scitigraphic methods, especially single photon emission computed tomography (SPECT) are becoming more popular. PATIENTS AND METHODS. Data of 98 outpatients who underwent planar ventilation/perfusion (V/Q) scintigraphy and 49 outpatients who underwent V/Q SPECT from the emergency department (ED) were retrospectively collected. Planar V/Q images were interpreted according to 0.5 segment mismatch criteria and revised PIOPED II criteria and perfusion scans according to PISA-PED criteria. V/Q SPECT images were interpreted according to the criteria suggested in EANM guidelines. Final diagnosis of PE was based on the clinical decision of an attending physician and evaluation of a 12 months follow-up period. RESULTS: Using 0.5 segment mismatch criteria and revised PIOPED II, planar V/Q scans were diagnostic in 93% and 84% of cases, respectively. Among the diagnostic planar scans readings specificity for 0.5 segment mismatch criteria was 98%, and 99% for revised PIOPED II criteria. V/Q SPECT showed a sensitivity of 100% and a specificity of 98%, without any non-diagnostic cases. In patients with low pretest probability for PE, planar V/Q scans assessed by 0.5 segment mismatch criteria were diagnostic in 92%, and in 85% using revised PIOPED II criteria, while perfusion scintigraphy without ventilation scans was diagnostic in 80%. CONCLUSIONS: Lung scintigraphy yielded diagnostically definitive results and is reliable in ruling out PE in patients from ED. V/Q SPECT has excellent specificity and sensitivity without any non-diagnostic results. Percentage of non-diagnostic results in planar lung scintigraphy is considerably smaller when 0.5 segment mismatch criteria instead of revised PIOPED II criteria are used. Diagnostic value of perfusion scintigraphy according to PISA-PED criteria is inferior to combined V/Q scintigraphy; the difference is evident especially in patients with low pretest probability for PE

Necrolytic migratory erythema associated with hyperglucagonemia and neuroendocrine hepatic tumors

We present a 61-year-old man with a 2-year history of persistent disseminated, psoriasiform annular pruritic lesions, acrodermatitis, weight loss, anemia and diabetes. Histopathology of the affected skin showed nonspecific subacute psoriasiform dermatitis. The computed tomographic scan of the abdomen revealed multiple hepatic tumors. Histopathological examination of ultrasound-guided needle biopsy from a hepatic lesion demonstrated a neuroendocrine tumor. Somatostatin-receptor scintigraphy with radio-labelled octreotide confirmed the likelihood of the neuroendocrine nature of the hepatic tumors and excluded the presence of other such lesions throughout the rest of the body, including the pancreas. The serum glucagon level was markedly increased. The diagnosis of necrolytic migratory erythema associated with hyperglucagonemia and neuroendocrine hepatic tumors was made and therapy with the long-acting somatostatin analogue octreotide was started. The skin changes resolved after the initiation of therapy, but no improvement of other symptoms was observed. Having reached the final stage of the disease, which was further complicated by congestive heart failure, the patient died one year later. As no autopsy was performed, we were unable to establish whether the hepatic tumors represented a metastatic process of previously undetected pancreatic glucagonoma or if they were extra-pancreatic glucagon-secreting tumors. The correct diagnosis of necrolytic migratory erythema is important, since it might be the clue for early detection of glucagonoma or of extra-pancreatic glucagon-secreting tumors

Thyroid lesions incidentally detected by 18F-FDG PET-CT ― a two centre retrospective study

Background. Incidental 18F-FDG uptake in the thyroid on PET-CT examinations represents a diagnostic challenge. The maximal standardized uptake value (SUVmax) is one possible parameter that can help in distinguishing between benign and malignant thyroid PET lesions

Thyroid lesions incidentally detected by 18

BACKGROUND. Incidental (18)F-FDG uptake in the thyroid on PET-CT examinations represents a diagnostic challenge. The maximal standardized uptake value (SUV(max)) is one possible parameter that can help in distinguishing between benign and malignant thyroid PET lesions. PATIENTS AND METHODS. We retrospectively evaluated (18)F-FDG PET-CT examinations of 5,911 patients performed at two different medical centres from 2010 to 2011. If pathologically increased activity was accidentally detected in the thyroid, the SUV(max) of the thyroid lesion was calculated. Patients with incidental (18)F-FDG uptake in the thyroid were instructed to visit a thyroidologist, who performed further investigation including fine needle aspiration cytology (FNAC) if needed. Lesions deemed suspicious after FNAC were referred for surgery. RESULTS. Incidental (18)F-FDG uptake in the thyroid was found in 3.89% — in 230 out of 5,911 patients investigated on PET-CT. Malignant thyroid lesions (represented with focal thyroid uptake) were detected in 10 of 66 patients (in 15.2%). In the first medical centre the SUV(max) of 36 benign lesions was 5.6 ± 2.8 compared to 15.8 ± 9.2 of 5 malignant lesions (p < 0.001). In the second centre the SUV(max) of 20 benign lesions was 3.7 ± 2.2 compared to 5.1 ± 2.3 of 5 malignant lesions (p = 0.217). All 29 further investigated diffuse thyroid lesions were benign. CONCLUSIONS. Incidental (18)F-FDG uptake in the thyroid was found in 3.89% of patients who had a PET-CT examination. Only focal thyroid uptake represented a malignant lesion in our study — in 15.2% of all focal thyroid lesions. SUV(max) should only serve as one of several parameters that alert the clinician on the possibility of thyroid malignancy

Metabolic Correlates of Dopaminergic Loss in Dementia with Lewy bodies

BACKGROUND: Striatal dopamine deficiency and metabolic changes are well-known phenomena in dementia with Lewy bodies and can be quantified in vivo by 123 I-Ioflupane brain single-photon emission computed tomography of dopamine transporter and 18 F-fluorodesoxyglucose PET. However, the linkage between both biomarkers is ill-understood. OBJECTIVE: We used the hitherto largest study cohort of combined imaging from the European consortium to elucidate the role of both biomarkers in the pathophysiological course of dementia with Lewy bodies. METHODS: We compared striatal dopamine deficiency and glucose metabolism of 84 dementia with Lewy body patients and comparable healthy controls. After normalization of data, we tested their correlation by region-of-interest-based and voxel-based methods, controlled for study center, age, sex, education, and current cognitive impairment. Metabolic connectivity was analyzed by inter-region coefficients stratified by dopamine deficiency and compared to healthy controls. RESULTS: There was an inverse relationship between striatal dopamine availability and relative glucose hypermetabolism, pronounced in the basal ganglia and in limbic regions. With increasing dopamine deficiency, metabolic connectivity showed strong deteriorations in distinct brain regions implicated in disease symptoms, with greatest disruptions in the basal ganglia and limbic system, coincident with the pattern of relative hypermetabolism. CONCLUSIONS: Relative glucose hypermetabolism and disturbed metabolic connectivity of limbic and basal ganglia circuits are metabolic correlates of dopamine deficiency in dementia with Lewy bodies. Identification of specific metabolic network alterations in patients with early dopamine deficiency may serve as an additional supporting biomarker for timely diagnosis of dementia with Lewy bodies. © 2019 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.status: accepte