The use of a novel method for SPECT/CT quantification of 99m-Tc-PYP uptake in the evaluation of ATTR cardiac amyloidosis

Funding Acknowledgements Type of funding sources: None. Background/Introduction: Bone scintigraphy with 99m-Technecium-Pyrophosphate (99m-Tc-PYP) with planar and SPECT imaging is now commonplace for the non-invasive diagnosis of ATTR cardiac amyloidosis. However, the quantification of 99m-Tc-PYP uptake is based on a semi-quantitative visual score and a heart to contralateral lung ratio which suffer from poor reproducibility. A more robust method of quantifying uptake and reporting results would be beneficial and may be possible using volumetric assessment with fused SPECT/CT acquisition. Purpose The aim of this study was to evaluate the performance of a novel semi-automated quantitative software to diagnose ATTR cardiac amyloidosis in patients with a clinical suspicion of cardiac amyloidosis who underwent 99m-Tc-PYP SPECT/CT imaging. Methods This was a retrospective, single-center study of consecutive patients who underwent 99m-Tc-PYP SPECT/CT imaging from September to December 2020. Quantification software was used to obtain standardized uptake values (SUVs) of 99m-Tc-PYP activity in the whole heart using SPECT/CT data. The total SUVs, mean SUVs, and percentage of injected tracer dose in the heart, as well as two other sets of these measurements adjusted for residual blood pool activity were obtained. Activity in the lung and bone was used to calculate heart to bone and heart to right lung ratios. The results from the software quantification were compared to the results from planar imaging as well as to the final clinical diagnosis of amyloidosis. Results A total of 59 patients were imaged during this time with an average age of 74.1 ± 11.8, and 32 (54.2%) were male. After excluding 8 patients for technical issues, 12 patients were found to be positive for amyloid, 39 were negative, and the average imaging delay time was 75.0 ± 15.2 minutes. 13 methods of assessment were evaluated with the metric of the percentage of injected tracer dose found in the heart that was adjusted for the mean residual blood pool activity having the best discrimination between abnormal and normal studies. The mean percentage of injected dose in positive patients was 2.87% vs 0.98% in the patients without amyloidosis (p < 0.0001). Using a cutoff of 2% to ensure that no patients with amyloid would be missed by screening, there was 100% sensitivity, 94.9% specificity, and 96.1% accuracy. There was a significant difference in the percentage injected dose based on gradations of planar heart to contralateral lung ratio and planar visual score. Conclusion Volumetric software quantification may be a superior method of evaluating 99m-Tc-PYP cardiac amyloidosis studies. This methodology may allow for a quantitative definition of a normal or abnormal 99m-Tc-PYP cardiac amyloid study and provide for the potential of following response to therapy.

Implementing a Specialist Integrated Haematological Malignancy Imaging Reporting Paradigm to Lymphoma Radiology Assessment Can Significantly Improve the Quality of Data for Patient Management and Clinical Research

Introduction Comprehensive, accurate assessment by radiologists of PET and CT data is crucial for effective staging, prognostication, response assessment and clinical research in lymphoma. Clinicians require evaluation of disease burden at important nodal and extranodal review sites, review of anatomical sites where toxicity or complications of treatment might be evident, and measurement of parameters specific to lymphoma assessment such as bulk, metabolic SUV and Deauville Score. Ideally, integrated conclusions from multimodal radiological data on staging and treatment response by the radiologist enable appropriate decisions on management to be made at multidisciplinary team meetings and can improve quality of data for clinical research. Methods Hodgkin Lymphoma (HL) and Diffuse Large B-Cell Lymphoma (DLBCL) are the two lymphoma subtypes where there is most published evidence for the application of PET and CT. Key PET and CT parameters deemed clinically important in the management of HL and DLBCL at 3 time points - staging, interim and end of treatment - were identified. These parameters are listed in Figure 1. We performed a retrospective review of PET and CT reports at these 3 time points for 20 cases each of HL and DLBCL, over a 5- year period from 2013-2018, to assess the proportion of reports that included each of these key radiological parameters. Results Analysis of staging scan reports demonstrated that disease stage was not recorded in 5% of HL reports and 35% of DLBCL reports. 90% of HL reports did not include a statement of the number of involved nodal groups. The involved nodal groups were however described in 100% of reports. 90% of HL reports did not state whether there was extranodal involvement of disease, but extranodal sites were described in 60% of cases. 50% of DLBCL reports did not include the number of extranodal sites. A measurement of the largest single lesion was not given in 20% of HL and 30% of DLBCL reports. In 75% of HL reports and 55% of DLBCL reports, it was not stated whether there was evidence of bulk. With regard to cases where mediastinal disease was noted, 100% of HL and 89% of DLBCL reports had no documentation of whether there was evidence of SVC obstruction. In 100% of these cases for both HL and DLBCL, there was no documentation of whether there was evidence of thrombus. In terms of PET reports in HL, analysis of interim and end of treatment (EOT) reports demonstrated that SUV max was not given in 45% of interim and 60% of EOT reports. Mediastinal blood pool activity was not given in 85% of interim and 85% of EOT reports. Liver blood pool activity was not given in 95% of interim and 95% of EOT reports. Deauville score was not stated in 75% of interim and 85% of EOT reports. Response classification was not stated in 15% of interim and 40% of EOT reports. With regard to assessment for potential Bleomycin toxicity, the lung parenchyma was not commented on in 40% of interim and 45% of EOT reports. For DLBCL, SUV max was not given in 71% of interim PET scan reports and 65% of EOT reports. Mediastinal blood pool activity was not given in 86% of interim and 95% of EOT reports. Liver blood pool activity was not given in 100% of interim and 90% of EOT reports. Deauville Score was not given in 71% of interim and 80% of EOT reports. Response classification was not stated in 29% of interim and 15% of EOT reports. Conclusion Our data demonstrates retrospective evidence that a significant proportion of imaging reports in HL and DLBCL lack inclusion of radiological parameters crucial to staging, prognostication and response assessment in lymphoma, and required by clinicians to make appropriate management decisions. We therefore propose the implementation of a reporting framework including the parameters outlined in our study, to improve the quality of image reporting in lymphoma and have a positive impact on patient outcomes. Given that lymphoma imaging increasingly involves the use of multiple modalities, we further propose an integrated, standardised radiology reporting framework, under the title 'Specialist Integrated Haematological Malignancy Imaging Reporting', to improve patient outcomes and benefit clinical research. Disclosures Iyengar: Abbvie: Honoraria; Janssen: Honoraria.

Efficacy of Cardiac Blood Pool Activity in Hepatobiliary Scintigraphy for Diagnosis of Neonatal Hepatitis in Patients with Suspected Biliary Atresia

<p><strong><em>Background</em></strong><strong>:</strong> Biliary atresia (BA) is the commonest fatal liver disorder in children. It results from developmental anomaly due to fibrosis of extra hepatic bile ducts. The reported global incidence of biliary atresia varies from 5/100,000 to 32/100,000 live births. Accurate diagnosis is important before 8 weeks of age, since hepatoportoenterostomy (Kasai’s procedure) has a 90% success rate at this stage whereas success rate drops to 20% beyond 3 months. On the other hand, neonatal hepatitis (NH) which is other most common cause of neonatal cholestasis (NC) needs conservative treatment. So, differentiation of biliary atresia from neonatal hepatitis is very crucial. Hepatobiliary scintigraphy (HBSG) is most popular method to differentiate biliary atresia from neonatal hepatitis. But in severe neonatal hepatitis the diagnosis become inconclusive when excretion of radiotracer in bowel become absent along with prolonged cardiac activity. Prolonged cardiac blood pool activity in hepatobiliary scintigraphy is an indication of hepatocyte destruction in neonatal hepatitis. The aim of the study was to assess the efficacy of cardiac blood pool in hepatobiliary scintigraphy for diagnosis of neonatal hepatitis in suspected biliary atresia patient.</p><p><strong><em>Patients and methods:</em></strong> A total of 24 infants with history of conjugated hyperbilirubinaemia underwent HBSG showed prompt cardiac blood pool activity (9 infants) and also with prolonged cardiac blood pool (15 infants) with no excretion of radiotracer in bowel either in early or delayed images was included in the study. The findings of HBSG were compared with percutaneous liver biopsy findings and analyzed.</p><p><strong><em>Result:</em></strong><strong> </strong>Among 24 infants prolonged cardiac blood pool activity in HBSG was observed in 11 (73.3%) BA infants and 4 (44.4%) of NH infants. Absent bowel activity with prompt clearance of cardiac blood pool activity was observed in 4 (26.7%) BA infants and 5 (55.6%) NH infants. The difference was not statistically significant (<em>p</em>&gt;0.05).The calculated sensitivity of cardiac blood pool activity in HBSG for evaluation of NH was 44.4%, specificity was 26.7%, accuracy was 33.3%, positive predictive value (PPV) was 26.7% and negative predictive value (NPV) was 44.4%. The sensitivity, specificity, PPV, NPV and accuracy were low due to large number of false positive infants which might be due to complete obstruction of bile duct or due to early hepatocyte destruction (within 3 months of age).</p><p><strong><em>Conclusion:</em></strong><strong> </strong>Although prolonged cardiac blood pool activity was considered as diagnostic criteria for the diagnosis of NH in suspected BA patient but it could not be able to differentiate these two conditions.</p><p>Bangladesh J. Nuclear Med. 20(2): 124-128, July 2017</p>

Adenocarcinoma with BAC Features Presented as the Nonsolid Nodule Is Prone to Be False-Negative on18F-FDG PET/CT

Purpose. The present study investigated which type of adenocarcinoma with BAC features was prone to be false-negative on 18F-FDG PET/CT.Materials and Methods. A retrospective study was performed on 51 consecutive patients with localized adenocarcinoma with BAC features. CT and PET were assessed for lesion size, GGO percentage, and SUVmax. Lesions with FDG uptake the same as or more than mediastinal blood-pool activity were considered as PET-positive.Results. Of the 51 cases, 19.6% presented as pure GGO nodules, 31.4% as mixed nodules, and 49.0% as solid nodules. None of the pure GGO nodules was 18F-FDG avid, compared with 37.5% of mixed nodules and 96.0% of solid nodules (χ2=31.55,P=0.000). In the mixed nodule group, SUVmax was negatively correlated with GGO percentage (r=-0.588;P=0.021). The positive detection rate of 18F-FDG PET/CT was 50.0%, 55.6%, and 100% in tumors 1.1–2.0 cm, 2.1–3.0 cm, and >3.0 cm in diameter, respectively (χ2=5.815,P=0.055). General linear model factor analysis showed that the GGO was an important factor contributing to false-negative PET/CT results (F=23.992,P=0.000), but lesion size was not (F=0.602,P=0.866).Conclusions. The present study indicated that the adenocarcinoma with BAC features presented as nonsolid nodule is prone to be false negative on 18F-FDG PET/CT.

Decisive Diagnosis of Infected Mandibular Osteoradionecrosis with a Tc-99m-labelled Anti-granulocyte Fab′-fragment

SummaryThe accepted golden standard for detection of inflammatory bone disease is conventional three-phase bone scanning. Hyperperfusion, a high blood-pool activity and elevated bone metabolism are typical signs for an acute osteomyelitis. However, in case of subacute, chronic inflammation, neither elevated blood flow nor high blood-pool activity may be seen. This may cause difficulties in differentiating such cases from neoplastic or postoperative changes. This case report verifies the possible advantage of immunoscintigraphy with Tc-99m-labelled antigranulocyte Fab′-fragments (LeukoScan®) in a patient with infected mandibular osteoradionecrosis, who had equivocal clinical symptomes and questionable radiographic results. LeukoScan® is shown to be more sensitive in case of subacute bone inflammation compared with three-phase bone scanning. However, acquisition of delayed images after 24 hours including SPECT is inevitable in case of negative scans during the first hours of investigation.