Unexpected Artifact on 99mTc-Methylene Diphosphonate Bone Scintigraphy.

Asymmetric hot spots in the axial skeleton on bone scintigraphy may confound diagnosis. We describe an unexpected artifact of 99mTc-methylene diphosphonate near the breast in a 55-y-old woman with breast cancer. The initial whole-body bone scintigraphy revealed a solitary focal lesion in the anterior ribs on the left side. After careful tracking, we determined that this hot spot originated from the adhesive bandage. The patient had placed it in her left front pocket after removing it from the injection site. She was rescanned after the bandage had been removed from her pocket.

Disseminated Carcinomatosis of the Bone Marrow from Castration-Resistant Prostate Cancer Revealed by Choline Positron Emission Tomography-Computed Tomography.

Introduction: Disseminated carcinomatosis of the bone marrow is caused by cancer metastasis to the bone marrow and is the diagnosis is very difficult by imaging. Case Presentation: We report a 75-year-old male with disseminated carcinomatosis of the bone marrow from castration-resistant prostate cancer revealed by 11C-choline positron emission tomography-computed tomography (PET/CT). Although he already received radiotherapy to the prostate, combined androgen blockade, enzalutamide and apalutamide, and external beam radiotherapy for the pelvic bone metastases, serum prostate-specific antigen (PSA) value rapidly increased from 32 ng/mL to 104 ng/mL in recent 1 month. Bone scintigraphy showed almost no abnormal uptake in the whole body, whereas 11C-choline PET/CT showed diffuse bone marrow 11C-choline uptake. The disseminated carcinomatosis of the bone marrow was diagnosed from the discordant findings between bone scintigraphy and 11C-choline PET/CT examinations and confirmed pathologically by iliac marrow biopsy pathologically. Although docetaxel therapy was started, PSA value continued rising and he died after 4 months of the diagnosis. Conclusion: The discordant findings of choline PET/CT and bone scintigraphy can diagnose disseminated carcinomatosis of the bone marrow from prostate cancer.

Lincoln Sign: A Rare Presentation of Medication-related Osteonecrosis of the Jaw.

A 52-year-old female patient with metastatic breast cancer receiving denosumab for 7 years presented with marked diffuse tracer uptake in the mandible on Tc-99m-methylene diphosphonate bone scintigraphy, resembling the Lincoln sign. A diagnosis of medication-related osteonecrosis of the jaw (MRONJ) was confirmed, leading to immediate discontinuation of denosumab. Conservative therapy, including limited debridement and oral rinses, was initiated. MRONJ, a potential complication of bone-modifying agents, is more prevalent in advanced malignancy cases. The Lincoln sign has not been previously reported in MRONJ, emphasizing its consideration in cancer patients undergoing bone-modifying agent treatment.

Descriptive study of the clinical and myocardial status of a population with anatomopathological aortic valve amyloidosis.

BACKGROUND: Aortic stenosis (AS) and transthyretin (ATTR) cardiac amyloidosis (CA) share the same clinical profiles and cardiac phenotype. Amyloid deposits have been frequently reported in aortic valves of patients with severe AS referred for surgical aortic valve replacement (SAVR). The aim of this study was to determine the clinical and myocardial status of patients with aortic valve amyloidosis after aortic valve surgery. METHODS AND RESULTS: We performed a retrospective descriptive study of 46 patients who underwent SAVR for severe AS with amyloid deposits upon histological analysis. All patients were screened for cardiac involvement. Amyloid deposits typing was successful in 35 (76%) patients and 28 (80%) were ATTR. Two (4%) had positive bone scintigraphy and among the 5 myocardial biopsies performed during surgery, 80% were positive for ATTR deposits. CONCLUSION: ATTR is the predominant type in the presence of amyloid deposits on the aortic valve after surgery for severe AS but is only rarely accompanied by cardiac uptake on bone scintigraphy. Early stages of myocardial involvement are frequent and myocardial biopsy is more sensitive for detection of mild amyloid deposits than bone scintigraphy. underdiagnosed by bone scintigraphy.

Improvement of Whole-body Bone Planar Images on a Bone-dedicated Single-photon Emission Computed Tomography Scanner by Blind Deconvolution Algorithm.

Purpose: We have developed a bone-dedicated collimator with higher sensitivity but slightly degraded resolution on single-photon emission computed tomography (SPECT) for planar bone scintigraphy, compared with conventional low-energy high-resolution collimator. In this work, we investigated the feasibility of using the blind deconvolution algorithm to improve the resolution of planar images on bone scintigraphy. Materials and Methods: Monte Carlo simulation was performed with the NCAT phantom for modeling bone scintigraphy on the clinical dual-head SPECT scanner (Imagine NET 632, Beijing Novel Medical Equipment Ltd.) equipped with the bone-dedicated collimator. Maximum likelihood estimation method was used for the blind deconvolution algorithm. The initial estimation of point spread function (PSF) and iteration number for the method were determined by comparing the deblurred images obtained from different input parameters. We simulated different tumors in five different locations and with five different diameters to evaluate the robustness of the initial inputs. Furthermore, we performed chest phantom studies on the clinical SPECT scanner. The quantified increased contrast ratio (CR) between the tumor and the background was evaluated. Results: The 2 mm PSF kernel and 10 iterations provided a practical and robust deblurred image on our system. Those two inputs can generate robust deblurred images in terms of the tumor location and size with an average increased CR of 21.6%. The phantom studies also demonstrated the ability of blind deconvolution, using those two inputs, with increased CRs of 17%, 17%, 22%, 20%, and 13% for lesions with diameters of 1 cm, 2 cm, 3 cm, 4 cm, and 5 cm, respectively. Conclusions: It is feasible to use the blind deconvolution algorithm to deblur the planar images for SPECT bone scintigraphy. The appropriate values of the PSF kernel and the iteration number for the blind deconvolution can be determined using simulation studies.

When in Doubt, Add SPECT/CT: A Case of Mistaken Identity.

A 63-y-old woman with a history of breast cancer presented with concerns of osseous metastasis. Initial whole-body planar bone scintigraphy revealed a focus of concern overlying the sternum. SPECT/CT images revealed the anomaly-localized activity in the needleless hub attached to the chemotherapy port. If not for the precision of SPECT/CT, such a rare artifact could have led to a false-positive diagnosis, particularly impactful in breast cancer patients. This case emphasizes the critical role of SPECT/CT in accurate diagnoses.

Bone Scintigraphy for Guidance of Targeted Treatment of Vertebral Compression Fractures.

Background: Vertebral compression fractures (VCFs) are prevalent in the elderly population and might be the source of back pain if they are fresh and yet unhealed. In many cases, it is a diagnostic challenge to differentiate fresh VCFs from healed united fractures, which retain similar radiographic characteristics but no longer generate pain. This information is crucial for appropriate management. The aim of this study was to evaluate the role of bone scintigraphy (BS) in identifying fresh VCFs appropriate for targeted treatment when compared to the findings of Computerized Tomography (CT). Methods: We retrospectively reviewed 190 patients with back pain suspected to stem from a recent VCF that underwent both a CT and a BS and compared the imaging patterns per vertebra. Results: The studies were concordant in the majority of cases (95.5%), diagnosing 84.4% normal vertebrae, 6.4% acute VCFs, and 4.7% chronic VCFs. However, in 37 patients, 45 occult acute VCFs were only detected on BS and not on CT. Multivariate logistic regression analysis revealed that these patients were older and had lower bone density compared to the rest of the study population. Additionally, 40 patients had acute VCFs visible on CT, but with no increased or low intensity uptake on BS. These cases were associated with a shorter time period between trauma and BS, a higher prevalence of male patients, and a higher bone density. Acute VCFs with no increased uptake or low levels of uptake were found only within the first six days of the trauma. Conclusions: BS detects radiologically occult fractures and can differentiate if a radiographically evident VCF is indeed clinically active, guiding possible treatment options. To avoid missing acute VCFs, BS should be performed six days or more after the injury.

Erdheim-Chester disease and nuclear medicine imaging. A case report and brief review.

Erdheim-Chester disease (ECD) is a rare clonal myeloid neoplasm typically affecting adults over 50 years old, with bone lesions in almost all patients. The prognosis is poor in most cases if left untreated. Clinical manifestations are not specific, which hinders early diagnosis. The disease has distinct radiological features. However, three-phase bone scintigraphy exhibits the most typical pattern of all imaging modalities, which is the prominent strikingly symmetrical radiotracer uptake in the distal ends of the femurs and proximal and distal ends of the tibiae, sparing the epiphyses. We report a case of a 54-year-old female patient, presenting with atypical persistent knee joint pain. After an MRI scan, she underwent a three-phase bone scan, revealing the characteristic pattern, thus indicating a possible ECD diagnosis, which was eventually confirmed in biopsy material. Novel aspects of the pathophysiology and treatment of the disease, as well as a differential diagnosis from the perspective of an MSK radiologist and nuclear medicine physician, are also discussed.

Assessment of incidental cardiac uptake in bone scintigraphy across Spain: The ECCINGO study.

AIM: Myocardial uptake on bone scintigraphy has become useful for the detection of transthyretin cardiac amyloidosis (ATTR-CA). This study aimed to assess the prevalence of myocardial uptake in patients over 18 years of age with no clinical suspicion of cardiac amyloidosis (CA) who had undergone bone scintigraphy. METHODS AND RESULTS: This was an observational, retrospective, multicenter study across 21 Spanish hospitals (September-November 2019). Of the 9864 scans analyzed (locally and centrally), incidental cardiac uptake was observed in 71 patients (0.72%), a prevalence that increased with age. A previous diagnosis of heart failure was found in 16.9% of patients with positive uptake, with >50% in NYHA II. ATTR-CA was diagnosed in 10 patients, with a mean delay of 10.4 months (95% CI: 5.1-15.7). All were >70 years old, primarily male, and had greater left ventricular hypertrophy than patients without a confirmed diagnosis (p<0.0001). ATTR-CA patients had higher rates of orthostatic hypotension (30.0% vs. 3.8% in non-ATTR-CA; p=0.025). CONCLUSIONS: This is the first retrospective, national, multicenter study evaluating the prevalence of incidental cardiac uptake in bone scintigraphy performed for non-cardiac reasons, showing a prevalence of 0.72% in this population. Referral of these patients may facilitate early diagnosis of CA with a resulting benefit for patients.

Interest of targeted computed tomography guided by scintigraphy in the diagnosis of an osteoid osteoma of the talus: A surgical case report.

INTRODUCTION AND IMPORTANCE: Osteoid osteoma is a benign primary bone tumor with a predilection for the long bones and vertebrae, presenting a unique challenge when occurring in rare locations such as the talus, accounting for 5 to 8 % of cases. Early imaging struggles to detect its nidus, leading to diagnostic delays, especially when atypical symptoms and previous trauma complicate clinical presentations. This case report illustrates the diagnostic challenges and emphasizes the importance of targeted computed tomography (CT) guided by scintigraphy in diagnosing osteoid osteoma of the talus. CASE PRESENTATION: A 23-year-old male presented with chronic left ankle pain spanning three years, with a history of previous trauma. Initial evaluations including standard radiology and magnetic resonance imaging (MRI) suggested algodystrophy of the talus and tenosynovitis, but failed to identify the osteoma. Persistent pain led to further investigation with bone scintigraphy, revealing hyperfixation indicative of partial algodystrophy. Targeted CT scans focused on the scintigraphy-identified area ultimately revealed an osteoid osteoma's nidus, enabling successful surgical intervention and symptomatic relief. DISCUSSION: The diagnosis of osteoid osteoma in the talus is frequently delayed due to its atypical presentation and rare occurrence. Traditional imaging techniques may overlook the tumor's nidus, underscoring the necessity for targeted diagnostic approaches. This case demonstrates the value of integrating scintigraphy with targeted CT to enhance early diagnosis and treatment planning, contrasting with the limited diagnostic yield of MRI and underscoring CT's superiority for nidus detection. CONCLUSION: Osteoid osteoma of the talus poses significant diagnostic challenges. This case report highlights the utility of scintigraphy-guided targeted CT in identifying the nidus and facilitating prompt surgical management, advocating for a multidisciplinary approach to atypical ankle pain, especially in patients with a history of trauma.

Fast SPECT/CT planar bone imaging enabled by deep learning enhancement.

BACKGROUND: The application of deep learning methods in rapid bone scintigraphy is increasingly promising for minimizing the duration of SPECT examinations. Recent works showed several deep learning models based on simulated data for the synthesis of high-count bone scintigraphy images from low-count counterparts. Few studies have been conducted and validated on real clinical pairs due to the misalignment inherent in multiple scan procedures. PURPOSE: To generate high quality whole-body bone images from 2× and 3× fast scans using deep learning based enhancement method. MATERIALS AND METHODS: Seventy-six cases who underwent whole-body bone scans were enrolled in this prospective study. All patients went through a standard scan at a speed of 20 cm/min, which followed by fast scans consisting of 2× and 3× accelerations at speeds of 40 and 60 cm/min. A content-attention image restoration approach based on Residual-in-Residual Dense Block (RRDB) is introduced to effectively recover high-quality images from fast scans with fine-details and less noise. Our approach is robust with misalignment introduced from patient's metabolism, and shows valid count-level consistency. Learned Perceptual Image Patch Similarity (LPIPS) and Fréchet Inception Distance (FID) are employed in evaluating the similarity to the standard bone images. To further prove our method practical in clinical settings, image quality of the anonymous images was evaluated by two experienced nuclear physicians on a 5-point Likert scale (5 =  excellent) . RESULTS: The proposed method reaches the state-of-the-art performance on FID and LPIPS with 0.583 and 0.176 for 2× fast scans and 0.583 and 0.185 for 3× fast scans. Clinic evaluation further demonstrated the restored images had a significant improvement compared to fast scan in image quality, technetium 99m-methyl diphosphonate (Tc-99 m MDP) distribution, artifacts, and diagnostic confidence. CONCLUSIONS: Our method was validated for accelerating whole-body bone scans by introducing real clinical data. Confirmed by nuclear medicine physicians, the proposed method can effectively enhance image diagnostic value, demonstrating potential for efficient high-quality fast bone imaging in practical settings.

Radiological impact of oral bisphosphonate use on polyostotic Paget's disease of bone over a 2 year period.

Paget's disease of bone is a disorder of osteoclasts which hampers the physiological process of bone remodeling. It is the most common metabolic orthopedic disease in the Caucasian populace; we report the diagnosis of Paget's disease of bone in a South-Asian male in his early 50s with a history of gastrointestinal symptoms, weight loss and back pain. An alkaline phosphatase level of 1104 IU/L was noted. A 3-phase bone scan showed noncontiguous heterogenous nuclear uptake. After exhaustive evaluation, the patient was diagnosed with Paget's disease of bone. Despite the disease activity being mitigated by alendronate and monitored by ALP levels within normal range per protocol, the patient had compression fractures of the vertebrae requiring early reinitiation of oral bisphosphonates. This raised doubts about the efficacy of metabolic marker-based management in Paget's disease of bone.

Evaluation of two-dimensional total bone uptake (2D-TBU) and bone scan index (BSI) extracted from active bone metastatic burden on the bone scintigraphy in patients with radium-223 treatment.

OBJECTIVE: Radium-223 is a first alpha-emitting radionuclide treatment for metastatic castration-resistant prostate cancer (mCRPC) patients with bone metastases. Although the spread-based bone scan index (BSI) and novel index of the intensity-based two-dimensional total bone uptake (2D-TBU) from bone scintigraphy may provide useful input in radium-223 treatment, they have not been evaluated in detail yet. This study aimed to fill this gap by evaluating BSI and 2D-TBU in patients treated with radium-223. METHODS: Twenty-seven Japanese patients with mCRPC treated with radium-223 were retrospectively analyzed. The patients were evaluated via blood tests and bone scans at baseline and 3 cycles intervals of treatment. BSI and 2D-TBU were analyzed via VSBONE BSI in terms of correlations, response to radium-223 treatment, association with treatment completion, and the Kaplan-Meier survival analysis was performed. RESULTS: Nineteen patients (70.4%) completed six cycles of radium-223 treatment, whereas eight patients (29.6%) did not complete the treatment regimen. A significant difference in baseline BSI and 2D-TBU was observed between these groups of patients. Both BSI and 2D-TBU were highly correlated (r = 0.96, p < 0.001). Univariate analysis showed an association between radium-223 completion in median BSI and 2D-TBU values (p = 0.015) and completion percentage differences (91.7% vs. 45.5%; p = 0.027). The Kaplan-Meier product limit estimator showed that the median overall survival was 25.2 months (95% CI 14.0-33.6 months) in the completion group and 7.5 months (95% CI 3.3-14.2 months) in the without completion group (p < 0.001). The overall survival based on median cutoff levels showed a significant difference in 2D-TBU (p = 0.007), but not in BSI (p = 0.15). CONCLUSIONS: The 2D-TBU may offer advantages over BSI in classifying patients towards radium-223 treatment based on the degree of progression of bone metastases. This study supports the importance of preliminary assessment of bone metastasis status using BSI and 2D-TBU extracted from VSBONE BSI for radium-223 treatment decisions.

A statistical symptomatic evaluation on SAPHO syndrome from 56 cases of confirmed diagnosis and 352 cases of non-SAPHO involvement.

OBJECTIVE: To report a statistical evaluation of symptomatology based on 56 cases of SAPHO syndrome and 352 non-SAPHO involvement cases, to propose a symptomatic scoring system in consideration of early warning for SAPHO syndrome. METHODS: A cohort comprising 56 subjects diagnosed with SAPHO syndrome was reported, as well as 352 non-SAPHO involvement cases, including their chief complaints, skin manifestations, radiological findings, and laboratory tests. We systematically reviewed previous published five representative huge cohorts from different countries to conclude several specific features of SAPHO by comparing with our case series. The score of each specific index is based on respective incidence and comparison of two cohorts was performed. RESULT: In terms of complaint rates, all subjects of two cohorts suffered from osseous pain, which appeared in the anterior chest wall, spine, and limb which were calculated. In respect to dermatological lesions, SAPHO patients suffered from severe acne, and other patients (82.14%) accompanied with palmoplantar pustulosis. Having received radiological examinations, most SAPHO subjects rather than non-SAPHO involvement cases showed abnormal osteoarticular lesions under CT scanning and more detailed information under whole-body bone scintigraphy. Differences also emerged in elevation of inflammation values and rheumatic markers like HLA-B27. Based on our cases and huge cohorts documented, the early warning standard is set to be 5 scores. CONCLUSIONS: SAPHO syndrome case series with 56 subjects were reported and an accumulative scoring system for the early reminder on SAPHO syndrome was proposed. The threshold of this system is set to be 5 points. Key Points • Fifty-six patients diagnosed by SAPHO syndrome with detailed symptoms and radiological findings were reported. • Comparison was made between the 56 SAPHO patients and 352 non-SAPHO involvement cases. • An accumulative scoring system for the early reminder on SAPHO syndrome was proposed and the threshold of this system is set to be five points.

Verification of image quality improvement of low-count bone scintigraphy using deep learning.

To improve image quality for low-count bone scintigraphy using deep learning and evaluate their clinical applicability. Six hundred patients (training, 500; validation, 50; evaluation, 50) were included in this study. Low-count original images (75%, 50%, 25%, 10%, and 5% counts) were generated from reference images (100% counts) using Poisson resampling. Output (DL-filtered) images were obtained after training with U-Net using reference images as teacher data. Gaussian-filtered images were generated for comparison. Peak signal-to-noise ratio (PSNR) and structural similarity (SSIM) to the reference image were calculated to determine image quality. Artificial neural network (ANN) value, bone scan index (BSI), and number of hotspots (Hs) were computed using BONENAVI analysis to assess diagnostic performance. Accuracy of bone metastasis detection and area under the curve (AUC) were calculated. PSNR and SSIM for DL-filtered images were highest in all count percentages. BONENAVI analysis values for DL-filtered images did not differ significantly, regardless of the presence or absence of bone metastases. BONENAVI analysis values for original and Gaussian-filtered images differed significantly at ≦25% counts in patients without bone metastases. In patients with bone metastases, BSI and Hs for original and Gaussian-filtered images differed significantly at ≦10% counts, whereas ANN values did not. The accuracy of bone metastasis detection was highest for DL-filtered images in all count percentages; the AUC did not differ significantly. The deep learning method improved image quality and bone metastasis detection accuracy for low-count bone scintigraphy, suggesting its clinical applicability.

High-Sensitivity Cardiac Troponin T to Exclude Cardiac Involvement in TTR Variant Carriers and ATTRv Amyloidosis Patients.

(1) Background: Individuals carrying a pathogenic transthyretin gene variant (TTRv) are at high risk for developing hereditary transthyretin (ATTRv) amyloidosis and are routinely screened for the development of cardiomyopathy (ATTRv-CM). This study aims to evaluate whether the cardiac biomarkers N-terminal pro B-type natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (hs-cTnT) can be used to rule out ATTRv-CM. (2) Methods: In this retrospective case-control study, data from 46 ATTRv-CM patients and 101 TTRv carriers and ATTRv amyloidosis patients without cardiomyopathy were included. Binary logistic regression models were used to assess the ability of NT-proBNP and hs-cTnT to predict the diagnosis of ATTRv-CM. An optimal cutoff for the relevant biomarker(s) was determined based on a sensitivity of ≥99% and the highest possible percentage of additional tests avoided (%ATA) in the index dataset. (3) Results: Hs-cTnT demonstrated the highest predictive capabilities for ATTRv-CM. The addition of NT-proBNP did not improve the predictive model. A hs-cTnT cutoff of <6 ng/L resulted in a 97% sensitivity and a negative predictive value of 95% with a %ATA of 30% in the validation dataset. (4) Conclusion: In conclusion, hs-cTnT is a useful biomarker for excluding cardiac involvement in TTRv carriers and ATTRv amyloidosis patients and it has the potential to prevent unnecessary diagnostic procedures.

Emerging Role of Scintigraphy Using Bone-Seeking Tracers for Diagnosis of Cardiac Amyloidosis: AJR Expert Panel Narrative Review.

Amyloidoses are a complex group of clinical diseases that result from progressive organ dysfunction due to extracellular protein misfolding and deposition. The two most common types of cardiac amyloidosis are transthyretin amyloidosis (ATTR) and light-chain (AL) amyloidosis. Diagnosis of ATTR cardiomyopathy (ATTR-CM) is challenging owing to its phenotypic similarity to other more common cardiac conditions, the perceived rarity of the disease, and unfamiliarity with its diagnostic algorithms; endomyocardial biopsy was historically required for diagnosis. However, myocardial scintigraphy using bone-seeking tracers has shown high accuracy for detection of ATTR-CM and has become a key noninvasive diagnostic test for the condition, receiving support from professional society guidelines and transforming prior diagnostic paradigms. This AJR Expert Panel Narrative Review describes the role of myocardial scintigraphy using bone-seeking tracers in the diagnosis of ATTR-CM. The article summarizes available tracers, acquisition techniques, interpretation and reporting considerations, diagnostic pitfalls, and gaps in the current literature. The critical need for monoclonal testing of patients with positive scintigraphy results to differentiate ATTR-CM from AL cardiac amyloidosis is highlighted. Recent updates in guideline recommendations that emphasize the importance of a qualitative visual assessment are also discussed.

Ultra-fast whole-body bone tomoscintigraphies achieved with a high-sensitivity 360° CZT camera and a dedicated deep-learning noise reduction algorithm.

This study aimed to determine whether the whole-body bone Single Photon Emission Computed Tomography (SPECT) recording times of around 10 min, routinely provided by a high-sensitivity 360° cadmium and zinc telluride (CZT) camera, can be further reduced by a deep-learning noise reduction (DLNR) algorithm. METHODS: DLNR was applied on whole-body images recorded after the injection of 545 ± 33 MBq of [99mTc]Tc-HDP in 19 patients (14 with bone metastasis) and reconstructed with 100%, 90%, 80%, 70%, 60%, 50%, 40%, and 30% of the original SPECT recording times. RESULTS: Irrespective of recording time, DLNR enhanced the contrast-to-noise ratios and slightly decreased the standardized uptake values of bone lesions. Except in one markedly obese patient, the quality of DLNR processed images remained good-to-excellent down to 60% of the recording time, corresponding to around 6 min SPECT-recording. CONCLUSION: Ultra-fast SPECT recordings of 6 min can be achieved when DLNR is applied on whole-body bone 360° CZT-SPECT.

Cardiac [99mTc]Tc-hydroxydiphosphonate uptake on bone scintigraphy in patients with hereditary transthyretin amyloidosis: an early follow-up marker?

PURPOSE: There is a need for early quantitative markers of potential treatment response in patients with hereditary transthyretin (ATTRv) amyloidosis to guide therapy. This study aims to evaluate changes in cardiac tracer uptake on bone scintigraphy in ATTRv amyloidosis patients on different treatments. METHODS: In this retrospective cohort study, outcomes of 20 patients treated with the transthyretin (TTR) gene silencer patisiran were compared to 12 patients treated with a TTR-stabilizer. Changes in NYHA class, cardiac biomarkers in serum, wall thickness, and diastolic parameters on echocardiography and NYHA class during treatment were evaluated. RESULTS: Median heart/whole-body (H/WB) ratio on bone scintigraphy decreased from 4.84 [4.00 to 5.31] to 4.16 [3.66 to 4.81] (p < .001) in patients treated with patisiran for 29 [15-34] months. No changes in the other follow-up parameters were observed. In patients treated with a TTR-stabilizer for 24 [20 to 30] months, H/WB ratio increased from 4.46 [3.24 to 5.13] to 4.96 [ 3.39 to 5.80] (p = .010), and troponin T increased from 19.5 [9.3 to 34.0] ng/L to 20.0 [11.8 to 47.8] ng/L (p = .025). All other parameters did not change during treatment with a TTR-stabilizer. CONCLUSION: A change in cardiac tracer uptake on bone scintigraphy may be an early marker of treatment-specific response or disease progression in ATTRv amyloidosis patients.