99m-Tc TRODAT Single-Photon Emission Computerized Tomography Scan Image Compression using Singular Value Decomposition.

Introduction: The objective of the study was to compress 99m-Tc TRODAT single-photon emission computerized tomography (SPECT) scan image using Singular Value Decomposition (SVD) into an acceptable compressed image and then calculate the compression factor. Materials and Methods: The SVD of every image from the image dataset of 2256 images (of forty-eight 99m-Tc TRODAT SPECT studies [48 studies X 47 trans-axial images = 2256 trans-axial images]) was computed and after truncating singular values smaller than a threshold, the compressed image was reconstructed. The SVD computation time and percentage compression achieved were calculated for each image. Two nuclear medicine physicians visually compared compressed image with its original image, and labeled it as either acceptable or unacceptable. Compressed image having loss of clinical details or presence of compression artifact was labeled unacceptable. The quality of compressed image was also assessed objectively using the following image quality metrics: Error, structural similarity (SSIM), brightness, global contrast factor (GCF), contrast per pixel (CPP), and blur. We also compared the TRODAT uptake in basal ganglia estimated from the compressed image and original image. Results: Nuclear Medicine Physician labeled each image acceptable, as they found compressed image identical to its original image. The values of brightness, GCF, CPP, and blur metrics show that compressed images are less noisy, brighter, and sharper than its original image. The median values of error (0.0006) and SSIM (0.93) indicate that the compressed images were approximately identical to its original image. In 39 out of 48 studies, the percentage difference in TRODAT uptake (in basal ganglia from compressed and original image) was negligible (approximately equal to zero). In remaining 9 studies, the maximum percentage difference was 13%. The SVD computation time and percentage compression achieved for a TRODAT study were 0.17398 s and up to 54.61%, respectively. Conclusions: The compression factor up to 54.61% was achieved during 99m-Tc TRODAT SPECT scan image compression using SVD, for an acceptable compressed image.

68Ga-PSMA PET/CT Detecting Metastatic Lesion of RCC: Missed on 18F-FDG PET/CT.

ABSTRACT: Renal cell carcinoma (RCC) accounts for ~2% of global cancers and deaths. Survival depends on initial staging and shows poor survival rate in metastatic disease. CT and MRI are used for evaluating RCC, and PET/CT is used for metastatic disease assessment. We report a case of RCC, where both 18F-FDG and 68Ga-PSMA PET/CT showed increased uptake in liver metastatic lesions; however, a subhepatic peritoneal deposit showed uptake only in PSMA. Also, liver lesions were seen better in PSMA owing to lesser background uptake, suggesting a possibility of 68Ga-PSMA being a potential tracer for RCC evaluation.

99m-Tc MDP Bone Scan Image Enhancement using Pipeline Application of Dynamic Stochastic Resonance Algorithm and Block-Matching 3D Filter.

Introduction: In this pilot study, we have proposed and evaluated pipelined application of the dynamic stochastic resonance (DSR) algorithm and block-matching 3D (BM3D) filter for the enhancement of nuclear medicine images. The enhanced images out of the pipeline were compared with the corresponding enhanced images obtained using individual applications of DSR and BM3D algorithm. Materials and Methods: Twenty 99m-Tc MDP bone scan images acquired on SymbiaT6 SPECT/CT gamma camera system fitted with low-energy high-resolution collimators were exported in DICOM format to a personal computer and converted into PNG format. These PNG images were processed using the proposed algorithm in MATLAB. Two nuclear medicine physicians visually compared each input and its corresponding three enhanced images to select the best-enhanced image. The image quality metrics (Brightness, Global Contrast Factor (GCF), Contrast per pixel (CPP), and Blur) were used to assess the image quality objectively. The Wilcoxon signed test was applied to find a statistically significant difference in Brightness, GCF, CPP, and Blur of enhanced and its input images at a level of significance. Results: Images enhanced using the pipelined application of SR and BM3D were selected as the best images by both nuclear medicine physicians. Based on Brightness, Global Contrast Factor (GCF), CPP, and Blur, the image quality of our proposed pipeline was significantly better than enhanced images obtained using individual applications of DSR and BM3D algorithm. The proposed method was found to be very successful in enhancing details in the low count region of input images. The enhanced images were bright, smooth, and had better target-to-background ratio compared to input images. Conclusion: The pipelined application of DSR and BM3D algorithm produced enhancement in nuclear medicine images having following characteristics: bright, smooth, better target-to-background ratio, and improved visibility of details in the low count regions of the input image, as compared to individual enhancements by application of DSR or BM3D algorithm.

Vertebral and ribs enhancement in Tc-99m methylene diphosphonate bone scan image by blind deconvolution algorithm.

AIMS AND OBJECTIVES: The objective of the study was to restore Tc-99m methylene diphosphonate (MDP) bone scan image using blind deconvolution (BD) algorithm so that ribs, vertebrae, and lesions present in them become prominent. MATERIALS AND METHODS: Our study consists of retrospective data in which 356 Tc-99m MDP bone scan images (178 anterior and 178 posterior) were processed using dynamic stochastic resonance algorithm, block-matching 3D filter, and then restored using BD algorithm. Two nuclear medicine (NM) physicians compared restored image with its input image; they especially lookedfor: (a) improvement in lesions detectability, (b) artifacts if any, (c) deterioration in ribs and vertebra, and (d) contrast enhancement in adjacent vertebra and adjacent ribs. They selected one out of two (restored and input) images, which had better quality. The overall image quality was also assessed using the following image quality metrics: brightness, blur, global contrast factor, and contrast per pixel. The Wilcoxon signed-rank test was applied for finding significant difference between the value of image quality metrics of restored image and input image at level of significance alpha = 0.05. RESULTS: According to NM physicians, 80.3% (286 out of 356) of restored images were acceptable, whereas 19.6% (70 out of 356) were unacceptable. Ribs and vertebrae were prominent in 161 out of 178 posterior restored images. Lumbar vertebrae were enhanced and well differentiated from adjacent vertebrae in 125 out of 178 anterior restored images. The value of image quality metrics of restored and input images were found to be significantly different ( P -value < 0.0001). CONCLUSION: Ribs, vertebrae, and lesions present in them become prominent in the most of Tc-99m MDP bone scan images (80.3%) restored using BD algorithm.

Comparative Role of 18F-DOPA PET/CT and 131I-MIBG Scintigraphy in Neuroblastoma and Application of Curie and SIOPEN Scoring Systems in 18F-DOPA PET/CT.

Purpose: Neuroblastoma (NB) is childhood's most common extracranial solid malignancy. We have compared two imaging modalities, 131I-MIBG and 18F-DOPA PET/CT, to evaluate NB. Also, feasibility of the application of standardised scoring systems, SIOPEN and Curie scoring systems, in 18F-DOPA PET/CT was explored. Methods: Patients with histopathology-proven NB underwent 131I-MIBG (planar and SPECT/CT) and 18F-DOPA PET/CT scans, as per standard imaging protocols. Duration between scans ranged from 1 to 30 days (median = 8 days). Number of lesions in Curie and SIOPEN scoring systems applied on both modalities was compared. Results: Forty-six patients were included (M:F = 29:17) with a median age of 36 months. Both 131I-MIBG and 18F-DOPA scans were positive in 39 patients and negative in four patients. 18F-DOPA PET/CT was positive in additional three patients, in which 131I-MIBG was negative (p = 0.25). Overall, 18F-DOPA identified significantly greater number of lesions than 131I-MIBG, especially metastatic skeletal lesions (p < 0.05). Significant difference was observed between Curie scores in the two modalities, unlike SIOPEN scores. However, when the cut-off age of 18 months was taken, no significant difference was seen in either of the scoring systems in both the scans (p > 0.05). CS and SIOPEN scores were significantly higher in bone marrow-positive patients. Conclusion: 18F-DOPA PET/CT detected more lesions than 131I-MIBG but had little impact on staging of the disease. For evaluation of NB, both scans can be used interchangeably as per the availability. Furthermore, both SIOPEN and Curie scoring systems, standardised for MIBG, can also be used to semi-quantify disease extent in 18F-DOPA PET/CT. Supplementary Information: The online version contains supplementary material available at 10.1007/s13139-022-00762-6.

18F-FDG Versus Non-FDG PET Tracers in Multiple Myeloma.

Multiple myeloma (MM) accounts for 0.9% of cancer diagnoses, and incidence and mortality rate have increased in previous years. 18F-fluorodeoxyglucose (FDG) PET-computed tomography (CT) is an established modality for MM evaluation. MR imaging is helpful where 18F-FDG PET-CT is lacking. To standardize PET reporting, methods like Italian Myeloma Criteria for PET Use and Deauville criteria have been studied. Tracers like 11C-acetate and 11C-choline/18F-fluoromethylcholine (FCH) have shown higher sensitivity and detected more focal lesions and diffuse involvement than 18F-FDG PET-CT. 18F-FCH showed higher maximum standardized uptake value than 18FDG. 11C-methionine appears to be the best radiopharmaceutical, apart from 18F-FDG, for evaluating MM.

Epithelioid sarcoma and its outcome: a retrospective analysis from a tertiary care center in North India.

Aim: Clinicopatholgical findings and outcomes in epithelioid sarcoma (ES) patients. Materials & methods: ES patients registered in sarcoma clinic from 2015 to 2021. Results: There were 20 patients with median age of 26 years. Majority had distal ES (70%) and advanced disease (85%). In patients with advanced disease lymph nodes were involved in 65%, lungs in 58% and others in 35%. Among 14 patients who underwent biopsy outside our institute, nine (64.2 %) had been initially misdiagnosed. Response rates to doxorubicin (n = 12), pazopanib (n = 6), gemcitabine/docetaxel (n = 5), tazemetostat (n = 3) and immunotherapy (n = 2) used in various lines were 16, 16, 20, 33 and 0%, respectively. Conclusion: Our patients had an advanced-stage and distal ES, with a modest response to chemotherapy.

Epithelioid sarcoma is an uncommon subtype of soft tissue sarcoma with a variable clinical course. We analyzed the outcomes of 20 patients registered under our Sarcoma Medical Oncology clinic from 2015 to 2021. The majority of our patients had an advanced stage at presentation with lymph nodal and lung metastasis. Due to rarity and overlapping histological findings many patients may be initially misdiagnosed. Patients with advanced stages are treated with various chemotherapeutic agents, which have very low response rates. Tazemetostat has shown some promise with responses in up to a third of patients.

Chylopericardium Due to Residual Lymphangiomyoma Detected on 99mTc-Sulfur Colloid Lymphoscintigraphy.

ABSTRACT: Lymphangiomyomas are relatively rare, benign neoplasms. Many patients present with symptoms including effusions, and some cases are incidentally detected. Surgical excision is the treatment of choice, but because of its location, complete surgical resection of a lymphangioma can be technically difficult, and recurrent cases can present with symptoms including effusions. 99mTc-sulfur colloid scan can be used to confirm the leak and nature of the effusion fluid. Here, we present an 8-year-old girl with recurrent pleural and pericardial effusions after lymphocele excision and total pericardiectomy. 99mTc-sulfur colloid lymphoscintigraphy was done to rule out secondary chylopericardium.