Scintigraphic Studies Research Articles

8578 Papillary Thyroid Carcinoma in Autonomous Nodule with Low Risk Characteristics in Adolescent

Abstract Disclosure: A. Aponte Velez: None. M.M. Mangual Garcia: None. Thyroid nodules in children are uncommon but are known to carry a greater risk of malignancy than adult thyroid nodules. Additionally, differentiated thyroid cancer (DTC) in children is more commonly found with extrathyroidal extension and metastases which makes the approach and treatment similar but with important differences. The incidence of DTC in children is increasing, making a personalized evaluation of thyroid nodules in pediatric patients even more valuable. Guidelines recommend evaluation of nodules based on sonographic characteristics rather than size of nodule. However, not having worrisome sonographic characteristics may not be as reassuring as in adult patients. A 13 year old female patient presented with a palpable non tender right sided solid thyroid mass. She had no family history of thyroid cancer or history of irradiation. Thyroid function tests were remarkable for TSH:0.017 and positive thyroid stimulating immunoglobulin. Thyroid Ultrasound findings described heterogenous parenchyma with multiple discrete lesions on right thyroid lobe with a dominant solid isoechoic nodule at upper lobe measuring 2.1 x 3.5 x 1.9cm and a smaller nodule in lower lobe. Thyroid scan demonstrated a large functional hot nodule occupying most of right thyroid lobe with suppression of rest of thyroid parenchyma. Ultrasound guided FNA was performed of this lesion and results were negative for malignancy. Patient underwent total thyroidectomy with pathology report revealing right thyroid nodule encapsulated classical variant of papillary thyroid carcinoma. No lymph node metastases were identified. Non neoplastic thyroid parenchyma revealed chronic lymphocytic thyroiditis. Patient underwent radioiodine therapy with Whole Body Scan post radioiodine therapy demonstrating focal increased radionuclide localization at in region of neck consistent with functional thyroid tissue. There was no evidence of metastatic disease. In children, risk of malignancy is underestimated in ultrasonography and cytology. In this patient, papillary thyroid carcinoma was identified despite being stratified as having low risk of malignancy based on ultrasonography characteristics, hyperfunctioning nodule in scintigraphy study along with negative FNA results. Hyperfunctional nodules are usually reassuring for low risk of malignancy but rarely DTC can be found as in our patient. Guidelines agree that FNA is not recommended in functional nodules as surgical resection is the main therapy in children. However, surgery may be deferred if subclinical hyperthyroidism and low risk sonographic characteristics are present such as in our patient. If surgery had been deferred, based on low risk of malignancy, the risk of progression of disease would have been higher. Prognosis of DTC in children is good but the recurrence rate along with morbidity at such a young age may improve with more studies of DTC in children. Presentation: 6/2/2024

363. REFLUX MICRO-ASPIRATION: WHAT HAVE WE LEARNED

Abstract Background The accurate diagnosis of gastro-oesophageal reflux pulmonary microaspiration has only become possible recently with the introduction of a novel technique of reflux micro-aspiration scintigraphy study combined with single photon emission computed tomography (SPECT) combined with x-ray tomography (CT) in a hybrid instrument. This has allowed the accurate diagnosis of pulmonary and airway contamination with refluxate. Previously only patients with large volume symptomatic reflux aspiration were diagnosed clinically (Mendelson syndrome) or by 2-dimentional barium meal or an older plantar (2 dimensional) technique of scintigraphic aspiration studies. The concept of reflux micro-aspiration has been implicated in multiple pulmonary diseases but without absolute proof from an adequate diagnostic test. Little was known about the natural history, physiology, and response to treatment amongst patients with silent reflux micro-aspiration. The aim of this presentation is to summarise a series of research projects studying the natural history of the disease, common presenting symptoms, pathophysiology and response to treatment. Methods A prospectively populated database of patients referred to a tertiary specialist reflux diagnostic service with atypical and/or treatment resistant reflux was evaluated. The database contained records of consecutive patients including demographic information, presenting symptoms, investigations including imaging, upper gastro-intestinal physiology studies and novel reflux micro-aspiration scintigraphy studies. Treatment details including medical and surgical treatment and post treatment clinical information and investigations. Multiple studies were conducted using the information from the database and findings are summarised in this presentation. Results The novel reflux micro-aspiration scintigraphy with SPECT/CT was compared with other studies (multichannel intraluminal impedance and 24-hour pH monitoring) and was found to be sensitive to reflux occurring outside the oesophagus. Patients with reflux micro-aspiration can present a wide variety of symptoms, commonly a combination of typical symptoms of gastro-oesophageal reflux disease (heartburn and regurgitation) and respiratory symptoms. Reflux micro-aspiration was associated with reduced lower oesophageal sphincter pressure, severe ineffective oesophageal motility (IOM), and pharyngeal contamination with refluxate on reflux scintigraphy. Delayed liquid gastric emptying was not associated with reflux micro-aspiration, however gastroparesis with solids is associated with micro-aspiration. Micro-aspiration was common in patients with giant hiatus hernias and mostly resolved with surgery. Anti-reflux surgery resulted in resolution of aspiration in the majority of patients, however severe IOM was associated with lesser rates of microaspiration resolution. Conclusion Reflux micro-aspiration appears to be a more common manifestation of GORD than previously thought. The work summarised in this presentation discusses the presentation, physiological associations, and treatment of patients with reflux micro-aspiration.

Determination of fundic accommodation in gastric emptying scintigraphy. Evaluation of its clinical usefulness

AimGastric emptying scintigraphy is used to assess patients with symptoms of dyspepsia or gastroparesis. An alteration of fundus accommodation may explain these symptoms. The aim of this study was to determine the accommodation in gastric emptying scintigraphy studies performed in our institution. Material and methods50 patients (43 children) referred for gastric emptying assessment were evaluated. After fasting for 8 h, and following international guidelines, egg labeling was performed with 37 mBq of [99mTc]Tc-DTPA and administration of standardized food. Areas of interest were defined in the stomach at different times, and the corresponding retention percentages were calculated. Considering the image at time zero, gastric accommodation was qualitatively and quantitatively assessed, calculating the ratio between proximal stomach counts and total counts. ResultsOf the 50 patients studied, 32 had normal emptying, 10 had slowed emptying and 8 had accelerated emptying. Within the group of patients with normal emptying, 8 had altered accommodation (25%) and another 8 in the group with abnormal emptying (44%). Applying the ROC curve analysis to quantitative values, the most appropriate cut-off value was 0.785 with p < 0.001, sensitivity 82.4% and specificity 100%. ConclusionGastric emptying scintigraphy in addition to determining motility, made it possible to assess both qualitatively and quantitatively the distribution of the radiotracer in the stomach and thus, indirectly, the accommodation in the fundus. It provided added diagnostic information in a simple manner, without protocol changes and allowing more specific treatments to be assessed.

Prevalence and characteristics of patients with incidental cardiac uptake on bone scintigraphy

BackgroundBone scintigraphy is emerging as a confirmatory diagnostic tool for transthyretin cardiac amyloidosis (ATTR-CA). This study aimed to investigate the frequency and clinical characteristics of patients with incidental cardiac uptake and incidental ATTR-CA on bone scintigraphy.MethodsAll bone scintigraphic studies performed at a tertiary teaching hospital between 2011 and 2022 were reviewed retrospectively. Patients who underwent bone scintigraphy to confirm ATTR-CA were excluded. Patients with cardiac uptake of grade 2 or 3 were included and divided into two groups: possible ATTR-CA group and noncardiac amyloidosis (non-CA) group.ResultsOf the 61,432 bone scintigraphic studies performed on 32,245 patients, 23 (0.07%) had grade 2 or 3 cardiac uptake. Nine of 23 patients (39.1%) were assigned to the non-CA group because they showed cardiac uptake from definite other causes or focal uptake that did not match CA. The remaining 14 patients (60.9%) were classified as the possible ATTR-CA group, and five patients were referred to cardiologists and finally diagnosed with ATTR-CA. Two patients were treated with tafamidis. Patients in the ATTR-CA group were significantly older and had a less frequent history of end-stage renal disease than those in the non-CA group. Other characteristics were comparable in both groups.ConclusionsAlthough incidental ATTR-CA in patients undergoing bone scintigraphy for noncardiac reasons is uncommon, if cardiac uptake is observed in elderly patients without metastatic calcification associated with end-stage renal disease, further diagnostic work-up for ATTR-CA as a cause of undiagnosed heart failure should be considered.

Determinación de la acomodación fúndica en gammagrafía de vaciamiento gástrico. Valoración de su utilidad clínica

AimGastric emptying scintigraphy is used to assess patients with symptoms of dyspepsia or gastroparesis. An alteration of fundus accommodation may explain these symptoms. The aim of this study was to determine the accommodation in gastric emptying scintigraphy studies performed in our institution. Material and methods50 patients (43 children) referred for gastric emptying assessment were evaluated. After fasting for 8hours, and following international guidelines, egg labeling was performed with 37 mBq of [99mTc]Tc-DTPA and administration of standardized food. Areas of interest were defined in the stomach at different times, and the corresponding retention percentages were calculated. Considering the image at time zero, gastric accommodation was qualitatively and quantitatively assessed, calculating the ratio between proximal stomach counts and total counts. ResultsOf the 50 patients studied, 32 had normal emptying, 10 had slowed emptying and 8 had accelerated emptying. Within the group of patients with normal emptying, 8 had altered accommodation (25%) and another 8 in the group with abnormal emptying (44%). Applying the ROC curve analysis to quantitative values, the most appropriate cut-off value was 0.785 with p<0.001, sensitivity 82.4% and specificity 100%. ConclusionGastric emptying scintigraphy in addition to determining motility, made it possible to assess both qualitatively and quantitatively the distribution of the radiotracer in the stomach and thus, indirectly, the accommodation in the fundus. It provided added diagnostic information in a simple manner, without protocol changes and allowing more specific treatments to be assessed.

Lipid-Based Nanocarrier by Targeting with LHRH Peptide: A Promising Approach for Prostate Cancer Radio-Imaging and Therapy.

Prostate cancer is a prevalently detected malignancy with a dismal prognosis. Luteinizing-hormone-releasing-hormone (LHRH) receptors are overexpressed in such cancer cells, to which the LHRH-decapeptide can specifically bind. A lipid-polyethylene glycol-conjugated new LHRH-decapeptide analogue (D-P-HLH) was synthesized and characterized. D-P-HLH-coated and anticancer drug doxorubicin (DX)-loaded solid lipid nanoparticles (F-DX-SLN) were formulated by the cold homogenization technique and characterized by Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, differential scanning calorimetry, dynamic light scattering, electron microscopy, entrapment efficiency, and drug-release profile studies. F-DX-SLN allows site-specific DX delivery by reducing the side effects of chemotherapy. Cancer cells could precisely take up F-DX-SLN by targeting specific receptors, boosting the cytotoxicity at the tumor site. The efficacy of F-DX-SLN on PC3/SKBR3 cells by the MTT assay revealed that F-DX-SLN was more cytotoxic than DX and/or DX-SLN. Flow cytometry and confocal microscopic studies further support F-DX-SLNs' increased intracellular absorption capability in targeting LHRH overexpressed cancer cells. F-DX-SLN ensured high apoptotic potential, noticeably larger mitochondrial transmembrane depolarization action, as well as the activation of caspases, a longer half-life, and greater plasma concentration. F-DX-SLN/DX-SLN was radiolabeled with technetium-99m; scintigraphic imaging studies established its tumor selectivity in PC3 tumor-bearing nude mice. The efficacy of the formulations in cancer treatment, in vivo therapeutic efficacy tests, and histopathological studies were also conducted. Results clearly indicate that F-DX-SLN exhibits sustained and superior targeted administration of anticancer drugs, thus opening up the possibility of a drug delivery system with precise control and targeting effects. F-DX-SLN could also provide a nanotheranostic approach with improved efficacy for prostate cancer therapy.

Maximal detrusor pressure can be predicted using technetium-99m-mertcaptoacetyltriglycine renal scintigraphy in the early stages of spinal cord injury.

Retrospective cohort study. To investigate the potential of technetium-99m-mercaptoacetyltriglycine (99mTc-MAG-3) renal scintigraphy for predicting maximal detrusor pressure in the early stages of spinal cord injury (SCI). Tertiary rehabilitation facility. Medical records of individuals with SCI admitted between January 2020 and April 2023 who underwent both 99mTc-MAG-3 renal scintigraphy and urodynamic study within 90 days of SCI onset were retrospectively reviewed. Pearson's coefficient analysis was performed to determine the relationship between 99mTc-MAG-3 renal scintigraphy findings and urodynamic study findings. A multivariate linear regression analysis was performed to determine the best predictors of maximal detrusor pressure. A multivariate logistic regression analysis was performed to determine risk factors for high detrusor pressure. Ninety-four participants were enrolled in this study. Pearson's correlation analysis showed that effective renal plasma flow (ERPF) and ERPF (% predicted) were significantly correlated with maximal detrusor pressure. The multivariate linear regression analysis demonstrated that ERPF (% predicted) was a significant predictor of maximal detrusor pressure. The multivariate logistic regression analysis showed that ERPF (% predicted) was significantly associated with high detrusor pressure. The receiver operating characteristic curve demonstrated that the predictive model had an area under the curve of 0.725, with an ERPF (% predicted) cut-off of 64.05%, sensitivity 1.000, and specificity 0.429. These results suggest that 99mTc-MAG-3 renal scintigraphy may be useful for predicting high detrusor pressure in early SCI and may guide the timing of urodynamic studies in individuals with early SCI for appropriate management of neurogenic lower urinary tract dysfunction.

Nuclear medicine practice in Japan: a report of the ninth nationwide survey in 2022.

Subcommittee on Survey of Nuclear Medicine Practice in Japan has performed a nationwide survey of nuclear medicine practice every 5years since 1982 to survey contemporary nuclear medicine practice and its changes over the years. The subcommittee sent questionnaires, including the number and category of examinations as well as the kind of the radiopharmaceuticals during the 30days of June 2022 to all nuclear medicine institutes in Japan. The total numbers of them for the year 2022 were estimated depends on the 1-month data. A total of 1095 institutes responded to the survey, including 364 positron emission tomography (PET) centers. The recovery rate was 90.6%. The number of gamma cameras installed was 1299 in total, with 2.5% decrease in 5years. Dual-head cameras and hybrid SPECT/CT scanners accounted for 83.8% and 35.5%, respectively. The number of single-photon tracer studies in 2022 was 1.11million which means increase in 2.7% in 5years. Bone scintigraphy was a leading examination (31.0%), followed by myocardial scintigraphy (27.1%) and cerebral perfusion study (23.8%) in order. The percentage of SPECT studies showed an increase from 63.5% in previous survey to 66.8% in this survey. PET centers have also increased from 389 to 412, as compared with the previous one. One hundred and twenty-two PET centers have installed one or two in-house cyclotrons. Increasing trends of the PET studies were observed from 1992 to 2017, the trend changed and PET studies showed 1.5% decrease in 5years. 18F-FDG accounted for 98.6% (610,497 examinations). PET examinations using 11C-methionine, 13N-NH3 and 11C-PIB have decreased, with 1624, 2146 and 525 examinations, respectively in 2022. The total number of nuclear medicine examination was eventually increased by 1.0%. Therapies for pheochromocytoma or paraganglioma (PPGL) with 131I-MIBG and for neuroendocrine tumor with 177Lu-DOTA-TATE were newly started, however, a total number of targeted radionuclide therapy was decreased by 17.7% because 131I-radioiodine and 223Ra targeted therapies were decreased and supply of some radioisotopes was discontinued. 131I-radioiodine targeted therapy showed a decrease in 5years (- 15.9%), including 4099 patients for thyroid cancer. The number of out-patient thyroid bed ablation therapy with 1110MBq of 131I was also decreased to 1015 per year. The number of admission rooms specialized for radionuclide targeted therapy increased from 157 to 160. The number of 223Ra targeted therapies for castration-resistant metastatic prostate cancer (mCRPC) was 1041 patients. This survey was performed during COVID-19 pandemic, however, total number of nuclear medicine examinations was almost same as previous survey (+ 1.0%). Radionuclide therapies with 131I-MIBG and 177Lu-DOTA-TATE were newly started, and new radionuclide therapy will be available in future, therefore, the development of radionuclide therapy will be continued. We are convinced that this survey report is useful in understanding the current status of the nuclear medicine practice in Japan, and in devising the new strategy to strengthen a role ofnuclear medicine.

Left atrial diastasis strain slope is a marker of hemodynamic recovery in post-ST elevation myocardial infarction: the Laser Atherectomy for STemi, Pci Analysis with Scintigraphy Study (LAST-PASS).

Left atrial (LA) mechanics are strongly linked with left ventricular (LV) filling. The LA diastasis strain slope (LADSS), which spans between the passive and active LA emptying phases, may be a key indicator of the LA-LV interplay during diastole. This study aimed to investigate the LA-LV interdependencies in post-ST elevation myocardial infarction (STEMI), with particular focus on the LADSS. Patients with post-anterior STEMI who received primary percutaneous coronary intervention underwent contrast cardiac magnetic resonance imaging (MRI) during acute (5-9 days post-STEMI) and chronic (at 6 months) phases. The LADSS was categorized into three groups: Groups 1, 2, and 3 representing positive, flat, and negative slopes, respectively. Cross-sectional correlates of LADSS Group 2 or 3 compared to Group 1 were identified, adjusting for demographics, LA indices, and with or without LV indices. The associations of acute phase LADSS with the recovery of LV ejection fraction (LVEF) and scar amount were investigated. Sixty-six acute phase (86.4% male, 63.1 ± 11.8 years) and 59 chronic phase cardiac MRI images were investigated. The distribution across LADSS Groups 1, 2, and 3 in the acute phase was 24.2%, 28.9%, and 47.0%, respectively, whereas in the chronic phase, it was 33.9%, 22.0%, and 44.1%, respectively. LADSS Group 3 demonstrated a higher heart rate than Group 1 in the acute phase (61.9 ± 8.7 vs. 73.5 ± 11.9 bpm, p < 0.01); lower LVEF (48.7 ± 8.6 vs. 41.8 ± 9.9%, p = 0.041) and weaker LA passive strain rate (SR) (-1.1 ± 0.4 vs. -0.7 [-1.2 to -0.6] s-1, p = 0.037) in the chronic phase. Chronic phase Group 3 exhibited weaker LA passive SR [relative risk ratio (RRR) = 8.8, p = 0.012] than Group 1 after adjusting for demographics and LA indices; lower LVEF (RRR = 0.85, p < 0.01), higher heart rate (RRR = 1.1, p = 0.070), and less likelihood of being male (RRR = 0.08, p = 0.058) after full adjustment. Acute phase LADSS Groups 2 and 3 predicted poor recovery of LVEF when adjusted for demographics and LA indices; LADSS Group 2 remained a predictor in the fully adjusted model (β = -5.8, p = 0.013). The LADSS serves both as a marker of current LV hemodynamics and its recovery in post-anterior STEMI. The LADSS is an important index of LA-LV interdependency during diastole. https://clinicaltrials.gov/, identifier NCT03950310.

Appraisal of amyloidosis imaging practices in the Middle East/North Africa (PYP-MENA).

Whereas recommendations to optimize performance and yield of cardiac scintigraphy studies with bone-seeking tracers have been published, little is known about real-world adherence to these best practices, especially outside North America and Europe. Accordingly, we described imaging practices with this modality in a sample of nuclear laboratories in the Middle East/North Africa (MENA) region. Laboratories performing radionuclide imaging for cardiac amyloidosis in the MENA region were invited to participate in this study to describe installed camera systems, type and dose of bone-avid tracers used, imaging protocols, and criteria used for study interpretation. Out of 19 invited sites, 10 completed the survey (70% government-run; 90% accredited), sites have been involved with amyloid imaging for a median of 49 months (interquartile range 24-60). The median injected dose was 20 mCi (range 10-25), and PYP was used by 90% of sites in this sample. Planar imaging with single photon emission computed tomography (SPECT) reconstruction was performed at all sites, including seven sites that performed SPECT/CT reconstruction. Lastly, only 50% of sites relied on evidence of myocardial uptake by SPECT to confirm the diagnosis of ATTR cardiomyopathy, while the rest relied on visual assessment and heart/contralateral ratio. This study is the first to describe variation in imaging practices across sites in the MENA region, especially in acquisition protocols and interpretation standards. Eliminating heterogeneities identified by this study will harmonize image interpretation and reporting and will facilitate successful conduct of regional multi-centre studies.

Role of intraoperative entroscopy in obscure small bowel gastrointestinal bleed

ABSTRACT Obscure gastrointestinal bleed (OGIB) is defined as bleeding of unknown origin that persists or recurs after a negative initial or primary endoscopy (colonoscopy and upper gastrointestinal [GI] endoscopy) and imaging. Approximately 5% of all GI bleeding is obscure GI bleed. Abnormal blood vessels arteriovenous malformations (AVMs) cause 30%–40% of small intestinal bleeds. AVMs are the main source of bleeding in patients over the age of 50 years. Tumors (benign and malignant), polyps, Crohn’s disease, and ulcers are some of the other causes of bleeding. Various diagnostic modalities available to detect small intestinal bleed are upper GI endoscopy, colonoscopy, contrast-enhanced computed tomography scan of the abdomen with angiogram, small bowel enteroscopy, video capsule endoscopy, and scintigraphy studies. Advanced imaging/diagnostic modalities may not be available in all centers, posing a great challenge in the localization of the source of GI bleed. This series highlights the role of diagnostic laparoscopy with intraoperative enteroscope (IOE) in the management of OGIB.

Scintigraphic and Echocardiographic Study of Patients with Pathogenic or Probably Pathogenic Variants of the TTR Gene without Overt Cardiac Involvement.

Transthyretin amyloidosis (ATTR) is an infiltrative disease caused by abnormal protein deposition mainly in the heart and peripheral nervous system. When it affects the heart, the disease presents as restrictive cardiomyopathy; when it affects the peripheral and autonomic nervous system, it manifests as polyneuropathy, and is called familial amyloid polyneuropathy (FAP). There are two ATTR subtypes: wild-type ATTR, where there is no mutation, and mutant ATTR (ATTRm), which is characterized by a mutation in the gene encoding the transthyretin protein (TTR). In both subtypes, cardiac involvement is the major marker of poor prognosis. To assess the prevalence of subclinical cardiac involvement in a sample of patients with TTR gene mutation by using pyrophosphate scintigraphy and strain echocardiography; to compare scintigraphy and strain findings; to evaluate the association between neurological manifestations (FAP) and subclinical cardiac involvement; and to analyze whether there is an association between any specific mutation and cardiac involvement. This is a cross-sectional study with carriers of the TTR gene mutation, without cardiovascular symptoms or changes in electrocardiographic or conventional echocardiographic parameters. All patients underwent pyrophosphate scintigraphy and strain echocardiography. Subclinical cardiac involvement was defined as a Perugini score ≥ 2, heart-to-contralateral lung (H/CL) ratio ≥ 1.5 at 1 h, H/CL ≥1.3 at 3 h, or global longitudinal strain (GLS) ≤ -17%. Descriptive and analytical analyses were performed and Fisher's exact test and Mann-Whitney test were applied. A value of p < 0.05 was considered significant. The 23 patients evaluated had a median age of 51 years (IQR 37-57 years), 15 (65.2%) were female, 12 (52.2%) were Pardo, nine (39.1%) had systemic arterial hypertension, and nine (39.1%) had a previous diagnosis of FAP. Of the nine patients with FAP, 8 (34.8%) were on tafamidis. The associated mutations were Val142IIe, Val50Met, and IIe127Val. The median GLS in the sample was -19% (-16% to -20%). Of the 23 patients, nine (39.1%; 95% CI = 29-49%) met criteria for cardiac involvement, six (26%) by the GLS-based criteria only. There was no association between having FAP and being an asymptomatic carrier, as assessed by strain echocardiography and pyrophosphate scintigraphy (p = 0.19). The prevalence of systemic arterial hypertension, diabetes mellitus, dyslipidemia, smoking, and reduced GLS did not differ between groups. Septal e' wave velocity was the only variable that significantly differed between individuals with and without reduced GLS, with an area under the ROC curve of 0.80 (95% CI = 0.61-0.98, p = 0.027). The best diagnostic accuracy was achieved with a septal e' velocity ≤ 8.5 cm/s. There was no association between mutation type and preclinical cardiac involvement, nor between tafamidis use and lower degree of cardiac involvement (37.5% versus 40.0%, p = 0.90). Subclinical cardiac involvement was common in a sample of TTR mutation carriers without cardiac involvement. Reduced left ventricular GLS was the most frequent finding. There was no association between the presence of amyloid polyneuropathy and subclinical cardiac involvement. Type of mutation was not associated with early cardiac involvement. In this sample, the use of tafamidis 20 mg/day was not associated with a lower prevalence of subclinical cardiac involvement.

Temporal evolution of postsurgical bone repair in a rabbit model: A [99mTc]Tc-MDP scintigraphic study.

Bone regeneration is crucial for repairing bone tissue following various injuries. Research techniques that enable the study of metabolic changes in bone tissue under different conditions are important for understanding bone repair and remodeling. This study used bone scintigraphy to evaluate osteogenesis secondary to osteotomy in a preclinical model of New Zealand rabbits. For this purpose, we conducted a longitudinal, prospective, case-control study in which scintigraphic variables were measured in both the right forearm (case-operated) and the left forearm (control - non-operated). The study sample consisted of 10 rabbits subjected to osteotomy, followed by a 12-week postoperative evaluation period, divided into six imaging stages at 1, 2, 3, 4, 8, and 12 weeks. We observed that the operated forearm showed significantly higher external radiation than the control side, using the pinhole collimator, denoting an increase in the biodistribution and tropism of the radiopharmaceutical to the operated forearm. Among the three evaluated time points, osteoblastic activity was highest in the second week and presented a significant decline in the 8th and 12th weeks, denoting regeneration and resolution of the surgical injury; the control forearm was also influenced by the inactivity imposed by the operated forearm. This fact was notably evidenced by the reduction in the metabolic activity of osteoblasts in the left forearm. Our study suggested that bone scintigraphy was sensitive enough to semi-quantitatively differentiate the metabolic activity of osteoblasts in the operated forearm in the three temporal landmarks evaluated in the study.

Residual Pulmonary Vascular Obstruction Following Mechanical Thrombectomy for Submassive Pulmonary Embolism: A Single-Center Analysis

BackgroundResidual pulmonary vascular obstruction (RPVO) following pulmonary embolism (PE) is associated with residual dyspnea, recurrent venous thromboembolism, and chronic thromboembolic pulmonary hypertension. Historically, acute PE treated with anticoagulation alone results in high rates of significant RPVO. Contemporary treatment of submassive PE often involves catheter-based interventions, including mechanical thrombectomy (MT), although their relation to RPVO is not characterized. In this study, we aimed to evaluate the rate of ≥10% RPVO in patients treated with MT. MethodsTwenty consecutive patients with submassive PE in a single center underwent MT and subsequent planar ventilation/perfusion scintigraphy scan at a median of 4 months after thrombectomy. A quantitative perfusion score was calculated for each planar ventilation/perfusion scintigraphy study to provide a % perfusion defect. Complete hemodynamic data were collected during the procedure and Miller score was calculated using prepulmonary and postpulmonary angiography. Echocardiographic data were collected prior to, 24 to 48 hours after, and 30 days after the procedure. ResultsFour of 20 patients (20%) had ≥10% RPVO at a median of 4 months follow-up. Following MT, the mean Miller score decreased from 24.5 ± 2.9 to 15.8 ± 3.3 (P < .001) and mean pulmonary artery pressure decreased from 36.1 ± 4.8 mm Hg to 26.8 ± 5.4 mm Hg (P < .001). Right ventricle–to–left ventricle ratio decreased from 1.44 ± 0.2 to 1.05 ± 0.24 by 24 to 48 hours (P < .001) and 0.85 ± 0.1 at 30 days (P < .001) and right ventricular systolic pressure decreased from 63.2 ± 10 mm Hg to 42.1 ± 9.8 mm Hg at 24 to 48 hours (P < .001) and 31.9 ± 10.4 at 30 days (P < .001). ConclusionsIn this prospective study of patients with submassive PE treated with MT, favorable rates of RPVO were noted in comparison to prior studies of anticoagulation alone along with expected acute hemodynamic and echocardiographic improvements. While this study was small in scope, the results suggest the potential for long-term benefits of MT in acute PE in addition to the acute benefits previously described.

Increased radiopharmaceutical uptake in skeletal muscle in 26 flat racing and endurance horses (2017–2021)

SummaryBackgroundIncreased radiopharmaceutical uptake (IRU) in skeletal muscle in horses has been previously reported but only a few authors describe its location in detail.ObjectivesTo describe and document the distribution of IRU in skeletal muscle in a population of flat racing and endurance horses.Study designRetrospective descriptive study.MethodsBone phase nuclear skeletal scintigraphy studies of 17 endurance and 9 racehorses with IRU in skeletal muscle were reviewed. The affected muscles were described and differences between endurance and flat racing horses were analysed. Ultrasonographic appearance of the muscles with IRU was also described when available.ResultsA total of 22 hindlimb scans (14 endurance horses, 8 racehorses) and 7 forelimbs scans (5 endurance horses, 2 racehorses) were analysed. In the hindlimbs, IRU was most frequently observed in the semitendinosus muscle in endurance horses (7/14, 50%) and in the gluteus medius muscle in racehorses (4/8, 50%). Bilateral IRU in the same muscle was often observed (11/22, 50%) in the hindlimbs. In 87.5% of the studies with IRU in the biceps femoris (7/8) or the semitendinosus muscles (7/8), the IRU was bilateral. In the forelimbs, IRU was most frequently observed in the triceps brachii (2/5, 40%) and latissimus dorsi (2/5, 40%) muscles in endurance horses and in the brachiocephalicus muscle in racehorses (2/2, 100%). The distribution of the skeletal muscles with IRU was more varied in endurance than in flat racehorses. No statistically significant difference was found in the distribution of the skeletal muscles with IRU between endurance and racehorses.ConclusionsEven though no statistical differences between groups could be demonstrated, this study describes the frequent location of IRU in muscle in the semitendinosus of endurance horses and in the gluteus medius of flat racehorses included in this study. The distribution of muscles with IRU was more variable in endurance horses.

Determination of the optimal reconstruction for pancreaticoduodenal resection based on modified scintigraphy of gastrointestinal motility

Aim. To improve the outcomes of pancreaticoduodenal resection by determining the optimal reconstruction based on objective assessment of the functional state of the upper gastrointestinal tract using a modified “double” scintigraphic study.Materials and methods. 147 pancreaticoduodenal resections were performed in the period of 2016–2022. Patients underwent “double” scintigraphic study on days 30 and 90 after surgery. The mean age of the patients was 59.6 years (23–83); the male to female ratio was 1.27:1. All patients underwent gastropancreatoduodenal resection or pancreatoduodenal resection with pylorus preservation. The patients were divided into 3 groups according to the variant of the reconstructive stage of surgery. Group 1 underwent reconstruction according to Child, group 2 – Child reconstruction and interintestinal anastomosis formation according to Brown, the reconstructive stage in group 3 involved Roux-en-Y isolation of the small intestine (Roux-en-Y reconstruction).Results. “Double” scintigraphic study revealed that the best result on the 30th and 90th postoperative days was observed in patients who underwent pancreaticoduodenal resection with pylorus preservation, reconstructive stage according to Child and formation of interintestinal anastomosis after Brown.Conclusion. “Double” scintigraphy is an effective procedure to determine the motility of the stomach, biliodigestive anastomosis and motility of the small intestine. As a result, the optimal reconstruction after pancreaticoduodenal resection was determined in patients with neoplasms of the pancreatic head or the periampullary region and chronic pancreatitis.

ΔPSap4#5 surface-functionalized abiraterone-loaded nanoparticle successfully inhibits carcinogen-induced prostate cancer in mice: a mechanistic investigation

Prostate cancer (PCa) is one of the fatal illnesses among males globally. PCa-treatment does not include radiotherapy. Chemotherapy eventually causes drug resistance, disease recurrence, metastatic advancement, multi-organ failure, and death. Preclinical data on PCa-induced by carcinogens are truly scarce. Although some data on xenograft-PCa in animals are available, they mostly belonged to immuno-compromised animals. Here, we developed ΔPSap4#5 aptamer surface-functionalized abiraterone-loaded biodegradable nanoparticle (Apt-ABR-NP) to investigate its targeting ability to prostate-specific membrane antigen (PSMA) in carcinogen-induced PCa mice and the therapeutic efficacy of the formulation. Aptamers are called synthetic monoclonal antibodies for their target specificity. However, they are devoid of the toxicity problem generally associated with the antibody. Abiraterone is a testosterone and androgen inhibitor, a new drug molecule that shows good therapeutic efficacy in PCa. The developed nanoparticles were physicochemically characterized and used for various in vitro and in vivo investigations. Nanoparticles had an average size of 149 nm with sustained drug release that followed Korsmeyer–Peppas kinetics. In vitro investigation showed that Apt-ABR-NP produced 87.4% apoptotic cells and 95.3% loss of mitochondrial membrane potential in LNCaP cells after 48 h of incubation. In vivo gamma scintigraphy, live imaging, and biodistribution studies in prostate cancer animal models showed the predominant targeting potential of Apt-ABR-NP. Histopathological investigation showed the remarkable therapeutic efficacy of the formulation. The pharmacokinetic study showed an increased biological half-life and enhanced blood residence time of Apt-ABR-NP. Apt-ABR-NP therapy can thus minimize off-target cytotoxicity, reduce drug loss due to site-specific delivery, and deliver abiraterone in a sustained manner to the organ of interest. Thus, the present study brings new hope for better therapeutic management of PCa in the near future.Graphical

Intranasal cerium oxide nanoparticles improves locomotor activity and reduces oxidative stress and neuroinflammation in haloperidol-induced parkinsonism in rats.

Introduction: Cerium oxide nanoparticles (CONPs) have been investigated for their therapeutic potential in Parkinson's disease (PD) due to their potent and regenerative antioxidant activity. In the present study, CONPs were used to ameliorate the oxidative stress caused by free radicals in haloperidol-induced PD in rats following intranasal administration. Method: The antioxidant potential of the CONPs was evaluated in vitro using ferric reducing antioxidant power (FRAP) assay. The penetration and local toxicity of the CONPs was evaluated ex-vivo using goat nasal mucosa. The acute local toxicity of intranasal CONPs was also studied in rat. Gamma scintigraphy was used to assess the targeted brain delivery of CONPs. Acute toxicity studies were performed in rats to demonstrate safety of intranasal CONPs. Further, open field test, pole test, biochemical estimations and brain histopathology was performed to evaluate efficacy of intranasal CONPs in haloperidol-induced PD rat model. Results: The FRAP assay revealed highest antioxidant activity of prepared CONPs at a concentration of 25μg/mL. Confocal microscopy showed deep and homogenous distribution of CONPs in the goat nasal mucus layers. No signs of irritation or injury were seen in goat nasal membrane when treated with optimized CONPs. Scintigraphy studies in rats showed targeted brain delivery of intranasal CONPs and acute toxicity study demonstrated safety. The results of open field and pole test showed highly significant (p < 0.001) improvement in locomotor activity of rats treated with intranasal CONPs compared to untreated rats. Further, brain histopathology of treatment group rats showed reduced neurodegeneration with presence of more live cells. The amount of thiobarbituric acid reactive substances (TBARS) was reduced significantly, whereas the levels of catalase (CAT), superoxide dismutase (SOD), and GSH were increased significantly, while amounts of interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-α) showed significant reduction after intranasal administration of CONPs. Also, the intranasal CONPs, significantly high (p < 0.001) dopamine concentration (13.93 ± 0.85ng/mg protein) as compared to haloperidol-induced control rats (5.76 ± 0.70ng/mg protein). Conclusion: The overall results concluded that the intranasal CONPs could be safe and effective therapeutics for the management of PD.

Synthesis, Characterization, and Biological Evaluation of Radiolabeled Glutamine Conjugated Polymeric Nanoparticles: A Simple Approach for Tumor Imaging.

Application of nanoradiopharmaceuticals for molecular imaging has gained worldwide importance for their multifaceted potentials focusing on providing a safe and cost-effective approach. Biodistribution studies on such species are capable of bringing nanomedicine to patients. Current therapeutically available labeling strategies suffer from different limitations, including off-target cytotoxicity and radiolabel release over time. Poly(lactic-co-glycolic acid)(PLGA) nanoparticles are biodegradable carriers for a variety of contrast agents that can be employed in medicine with high loading capacity for multimodal imaging agents. Here, glutamine-conjugated PLGA polymers were used to construct polymeric nanoparticles (G-PNP) similar to unconjugated PLGA nanoparticles (PNP)s formulated for ex vivo cell labeling and in vivo tumor scintigraphy studies. G-PNP/PNP, characterized by Fourier-transform infrared, atomic-force-microscopy, particle-size, and zeta-potential studies, were biocompatible as evaluated by MTT assay. G-PNPs were radiolabeled with 99mtechnetium (99mTc) by borohydrite reduction. G-PNPs demonstrated higher cellular uptake than PNPs, with no major cytotoxicity. Radiochemical purity indicated that 99mTc labeled G-PNP (99mTc-G-PNP) can form a stable complex with substantial stability in serum with respect to time. Imaging studies showed that 99mTc-G-PNP significantly accumulated at the C6 glioma cell induced tumor-site in rats. Thus, 99mTc-G-PNP demonstrated favorable characteristics and imaging potential which may make it a promising tumor imaging nanoprobe as a nanoradiopharmaceutical.

Trends in diagnosis of cardiac transthyretin amyloidosis: 3-year analysis of scintigraphic studies: Prevalence of myocardial uptake and its predictor factors.

To determine the prevalence of myocardial uptake (MU) and to identify predictors of MU in patients undergoing scintigraphy. Retrospective single-center series of technetium-99m-labelled 3,3-diphosphono-1,2-propanodicarboxylic acid (99mTc-DPD) scans performed from March 2017 to March 2020. All patients undergoing scintigraphy were included, except those with preexisting amyloidosis. The features of MU, patients' characteristics and comorbidities were documented. Multivariate analysis was used to find items predicting MU. A total of 3,629 99mTc-DPD scans (total 11,444) were performed in patients aged > 70. The overall prevalence of MU was 2.7% (82/3,629); 1.2% in 2017-2018, to 2% in 2018-2019, and to 3.7% in 2019-2020. The prevalence of MU in patients without suspected cardiomyopathy was 1.2%; 1.1% in 2017-2018, 1.5% in 2018-2019 and 1% in 2019-2020. There is an increase in the number of requests due to suspected cardiomyopathy from 0.2% in 2017-2018 to 1.4% in 2018-2019 and to 4.8% in 2019-2020. Age, male sex, hypertension, heart failure, atrial fibrillation, atrioventricular block, aortic stenosis, and carpal tunnel syndrome were found to be predictors of MU. In patients without heart failure, only age, atrial fibrillation, and carpal tunnel syndrome were predicted MU. The prevalence of MU in scintigraphic studies surged over time due to the incremental referrals under the indication of cardiomyopathy workup. Atrial fibrillation and carpal tunnel syndrome were predictors for MU in patients without heart failure. Identifying patients with MU and no heart failure for extended screening for ATTR can lead to an earlier diagnosis and application of novel treatments.