Assessment of myocardial sympathetic innervation with 18F-FDOPA-PET/CT in patients with autonomic dysfunction: feasibility study in IPD patients.

BACKGROUND: Dysfunction and denervation of myocardial nor-adrenergic sympathetic neurons has been documented in IPD patients with dysautonomia. The aim of this study was to evaluate the feasibility of single tracer imaging of myocardial sympathetic and cerebral striatal involvement in these patients. METHODS: Twenty-two controls (mean-age 59.09 ± 12.39 years, 15 men) with no clinical autonomic-dysfunction and normal striatal-uptake in 18F-FDOPA-PET/CT; and 28 patients (mean-age 58.18 ± 8.25 years, 18 men) with autonomic-dysfunction (in Autonomic Function Tests) and striatal dopaminergic-dysfunction were enrolled. Both cardiac-PET/CT (40 minutes post IV-injection of 185-259MBq 18F-FDOPA) and Brain-PET/CT (60 minutes post-IV) were acquired in same session. ROIs were drawn over the entire left ventricular myocardium, individual walls and mediastinum for quantification. Patients and controls were followed-up for 26.93 ± 5.43 months and 37.91 ± 8.63 months, respectively. RESULTS: Striatal and myocardial-parameters were significantly lower in patients compared to controls; with Myocardium/mediastinal ratio (MwMR) yielding the area-under-the-curve of .941 (P < .001). MwMR correlated negatively with the drop in systolic blood pressure (SBP) during AFTs {Pearson-coefficient (-).565, P = .002}. Mean MwMR in patients with abnormal-AFTs was significantly lower than patients with borderline-AFTs (1.39 ± .12 vs 1.55 ± .10; P = .002). 9/20 patients with abnormal-AFTs showed functional worsening during follow-up, compared to 2/8 with borderline-AFTs. CONCLUSION: Single tracer, single session imaging of striatal and cardiac sympathetic dysfunction in patients with advanced IPD is feasible with use of 18F-FDOPA. Significantly reduced 18F-FDOPA uptake is seen in the myocardium of the IPD patients with sympathetic dysfunction.

Utility of 18F-FDG PET/CT in Detecting Spinal Drop Metastases from Pineal Gland Tumors.

Pineal gland tumors are significant despite being rare (<1%) among all brain tumors. Germ cell tumors are the most common among the pineal gland tumors. Often affecting young adults, pineal gland germ cell tumors are hard to diagnose due to different symptoms and potential spread. But they rarely show leptomeningeal spread and extracranial metastases. Other differentials include primary tumors of the pineal region, Pineal gliomas, and metastases. The leptomeningeal spread of these tumors has not been studied so far. Conventional radiological imaging modalities are routinely used to diagnose and evaluate these tumors. We report a case here showing a pineal gland tumor with leptomeningeal spread detected by 18F-FDG PET/CT. Our case shows how pineal gland tumors can behave unusually and how 18F-FDG PET/CT can be crucial for accurately assessing the extent of the disease in the body to provide effective treatment. This case report illustrates the rare type of spread of pineal gland tumor and how 18F-FDG PET/CT helps detect this rare type of metastasis, thereby helping in prognostication and deciding further treatment of the patient.

Nivolumab and Cabozantinib Immunotherapy Induced Thyroid Dysfunction Detected on 18 F-FDG PET/CT in Renal Cell Carcinoma.

ABSTRACT: Targeted immunotherapy became the most advanced approach for cancer treatment. Programmed death-1 (PD-1) expressed on activated T cells can reverse immune suppression and cause T-cell activation. Nivolumab, a PD-1 immune checkpoint inhibitor antibody that is a fully human immunoglobulin G4, blocks PD-1 and promotes antitumor immunity. Cabozantinib (tyrosine kinase inhibitor) inhibits the tyrosine kinase activity of vascular endothelial growth factor receptors 1, 2, and 3. As a result of enhancing immune response in normal tissues, immune-related adverse events can occur. Thyroid dysfunction is a common form of immune-related adverse event and seen on 18 F-FDG PET/CT scans post therapy.

Role of textural and radiomic analysis parameters in predicting histopathological parameters of the tumor in breast cancer patients.

INTRODUCTION: Texture and radiomic analysis characterizes the tumor's phenotype and evaluates its microenvironment in quantitative terms. This study aims to investigate the role of textural and radiomic analysis parameters in predicting histopathological factors in breast cancer patients. MATERIALS AND METHODS: Two hundred and twelve primary breast cancer patients underwent 18F-FDG PET/computed tomography for staging. The images were processed in a commercially available textural analysis software. ROI was drawn over the primary tumor with a 40% threshold and was processed further to derive textural and radiomic parameters. These parameters were then compared with histopathological factors of tumor. Receiver-operating characteristic analysis was performed with a P-value <0.05 for statistical significance. The significant parameters were subsequently utilized in various machine learning models to assess their predictive accuracy. RESULTS: A retrospective study of 212 primary breast cancer patients was done. Among all the significant parameters, SUVmin, SUVmean, SUVstd, SUVmax, discretized HISTO_Entropy, and gray level co-occurrence matrix_Contrast were found to be significantly associated with ductal carcinoma type. Four parameters (SUVmin, SUVmean, SUVstd, and SUVmax) were significant in differentiating the luminal subtypes of the tumor. Five parameters (SUVmin, SUVmean, SUVstd, SUVmax, and SUV kurtosis) were significant in predicting the grade of the tumor. These parameters showcased robust capabilities in predicting multiple histopathological parameters when tested using machine learning algorithms. CONCLUSION: Though textural analysis could not predict hormonal receptor status, lymphovascular invasion status, perineural invasion status, microcalcification status of tumor, and all the molecular subtypes of the tumor, it could predict the tumor's histologic type, triple-negative subtype, and score of the tumor noninvasively.

Complete Metabolic Response in Adenocarcinoma Lung With Lymphangitic Carcinomatosis.

ABSTRACT: Pulmonary lymphangitic carcinomatosis refers to the tumor spread into the lymphatic system of the lungs and is considered a poor prognostic marker. We present an interesting case of adenocarcinoma of right lung evaluated with 18 F-FDG PET/CT for baseline staging, with extensive bilateral lung involvement and lymphangitic carcinomatosis pattern. Subsequently, the patient received 3 cycles of carboplatin- and pemetrexed-based chemotherapy regimen along with oral ceritinib. Complete metabolic response and significant reduction in size of the primary lung lesion was noted on response evaluation with 18 F-FDG PET/CT, which is a rare phenomenon.

Nivolumab Immunotherapy-Related Skin Reactions Detected on 18F-FDG PET/CT in Renal Cell Cancer.

ABSTRACT: Nivolumab, a fully human immunoglobulin G4 anti-programmed cell death 1 antibody, provides a novel therapy option for patients with metastatic cancers. Immunotherapy agents have been associated with immune-related adverse events (irAEs), which may be detected on 18F-FDG PET/CT. Cutaneous toxicities are one of the most common irAEs in the form of maculopapular rash (eczema-like spongiotic dermatitis) and pruritus. These irAEs may lead to false-positive findings on PET/CT done during the treatment. One should be aware of the potential irAEs while interpreting PET/CT to avoid misinterpretation.

Bilateral Peritoneoscrotal Communication-"Chicken Leg" Appearance Demonstrated on 99mTc-Sulfur Colloid Scintigraphy.

Continuous ambulatory peritoneal dialysis is a convenient alternate form of treatment in patients receiving hemodialysis for renal failure. Sometimes during the procedure, patients may develop scrotal swelling because of patent processus vaginalis. The diagnostic utility of the peritoneal scintigraphy, an infrequently performed nuclear medicine scan to identify peritoneoscrotal communication, has been reported by many authors. Most of the previous case reports in the literature demonstrated unilateral peritoneoscrotal communication. We present an interesting Tc-sulfur colloid peritoneal scintigraphic image finding of bilateral peritoneoscrotal communication in a 67-year-old man who developed scrotal swelling while undergoing continuous ambulatory peritoneal dialysis.

Posterior Reversible Encephalopathy Syndrome: Pattern on 18F-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography Correlated with Magnetic Resonance Imaging in Pediatric Hypertensive Encephalopathy.

Posterior reversible encephalopathy syndrome (PRES) is characterized clinically by headache, seizures, vomiting, altered mental status, and blurred vision. However, with overlapping and atypical clinical symptoms, PRES becomes a diagnostic challenge. We describe the imaging findings of PRES in magnetic resonance imaging and 18F-fluorodeoxyglucose positron emission tomography-computed tomography in an 11-year-old child who presented with features of hypertensive encephalopathy.

Improving technetium-99m methylene diphosphonate bone scan images using histogram specification technique.

In this study, we have proposed and validated that histogram of a good-quality bone scan image can enhance a poor-quality bone scan image. The histograms of two good-quality technetium-99m methyl diphosphonate bone scan images IA and IB recommended by nuclear medicine physicians (NMPs) were used to enhance 87 poor-quality bone scan images. Processed images and their corresponding input images were compared visually by two NMPs with scoring and also quantitatively using entropy, Structural similarity index measure, edge-based contrast measure, and absolute brightness mean error. Barnard's unconditional test was applied with a null hypothesis that the histogram of both IA and IB produces similar output image at α =0.05. The mean values of quantitative metrices of the processed images obtained using IA and IB were compared using Kolmogorov-Smirnov test. Histogram of a good-quality bone scan image can enhance a poor-quality bone scan image. Visually, histogram of IB improved statistically significantly higher proportion (P < 0.0001) of images (86/87) as compared to histogram of IA (51/87). Quantitatively, IB performed better than IA, and the Chi-square distance of input and IB was smaller than that of IA. In addition, a statistically significant (P < 0.05) difference in all the quantitative metrics among the outputs obtained using IA and IB was observed. In our study, reference histogram of good-quality bone scan images transformed the majority of poor-quality bone scan images (98.85%) into visually good-quality images acceptable by NMPs.

Technetium-99m Labeled Tropane Derivative: Uptake in a Pituitary Macroadenoma.

We present a case of suspected idiopathic Parkinson's disease in whom extrastriatal accumulation of Technetium-99m labeled tropane derivatives in a pituitary macroadenoma interfered with image quality and interpretation. Subsequent F-18 fluoro-dihydroxyphenylalanine positron emission tomography/computed tomography was useful to demonstrate the absence of presynaptic dopaminergic dysfunction.

Tracer Accumulation in Relation to Venous Thrombus on 18F-DOPA PET/CT in a Case of Persistent Hyperinsulinemic Hypoglycemia of Infancy.

18F-DOPA PET/CT is commonly done in patients with persistent hyperinsulinemic hypoglycemia of infancy (PHHI) to look for any focal lesion in the pancreas. We present the findings in a 20-day-old neonate with PHHI who underwent 18F-DOPA PET/CT. The scan showed diffuse uptake in the pancreas with no focal lesion, physiologic excretion into the genito-urinary system, and interestingly tracer accumulation was seen in the inferior vena cava and ilio-femoral veins which is a non-physiological site for tracer accumulation. The uptake corresponded to a large venous thrombus which was confirmed by a venous Doppler.

Investigating the Role of Global Histogram Equalization Technique for 99mTechnetium-Methylene diphosphonate Bone Scan Image Enhancement.

PURPOSE OF THE STUDY: 99mTechnetium-methylene diphosphonate (99mTc-MDP) bone scan images have limited number of counts per pixel, and hence, they have inferior image quality compared to X-rays. Theoretically, global histogram equalization (GHE) technique can improve the contrast of a given image though practical benefits of doing so have only limited acceptance. In this study, we have investigated the effect of GHE technique for 99mTc-MDP-bone scan images. MATERIALS AND METHODS: A set of 89 low contrast 99mTc-MDP whole-body bone scan images were included in this study. These images were acquired with parallel hole collimation on Symbia E gamma camera. The images were then processed with histogram equalization technique. The image quality of input and processed images were reviewed by two nuclear medicine physicians on a 5-point scale where score of 1 is for very poor and 5 is for the best image quality. A statistical test was applied to find the significance of difference between the mean scores assigned to input and processed images. RESULTS: This technique improves the contrast of the images; however, oversaturation was noticed in the processed images. Student's t-test was applied, and a statistically significant difference in the input and processed image quality was found at P < 0.001 (with α = 0.05). However, further improvement in image quality is needed as per requirements of nuclear medicine physicians. CONCLUSION: GHE techniques can be used on low contrast bone scan images. In some of the cases, a histogram equalization technique in combination with some other postprocessing technique is useful.