Motion correction of PET/CT images

Indiana University-Purdue University Indianapolis (IUPUI)The advances in health care technology help physicians make more accurate diagnoses about the health conditions of their patients. Positron Emission Tomography/Computed Tomography (PET/CT) is one of the many tools currently used to diagnose health and disease in patients. PET/CT explorations are typically used to detect: cancer, heart diseases, disorders in the central nervous system. Since PET/CT studies can take up to 60 minutes or more, it is impossible for patients to remain motionless throughout the scanning process. This movements create motion-related artifacts which alter the quantitative and qualitative results produced by the scanning process. The patient's motion results in image blurring, reduction in the image signal to noise ratio, and reduced image contrast, which could lead to misdiagnoses. In the literature, software and hardware-based techniques have been studied to implement motion correction over medical files. Techniques based on the use of an external motion tracking system are preferred by researchers because they present a better accuracy. This thesis proposes a motion correction system that uses 3D affine registrations using particle swarm optimization and an off-the-shelf Microsoft Kinect camera to eliminate or reduce errors caused by the patient's motion during a medical imaging study

Fractal and multifractal analysis of PET-CT images of metastatic melanoma before and after treatment with ipilimumab

PET/CT with F-18-Fluorodeoxyglucose (FDG) images of patients suffering from metastatic melanoma have been analysed using fractal and multifractal analysis to assess the impact of monoclonal antibody ipilimumab treatment with respect to therapy outcome. Our analysis shows that the fractal dimensions which describe the tracer dispersion in the body decrease consistently with the deterioration of the patient therapeutic outcome condition. In 20 out-of 24 cases the fractal analysis results match those of the medical records, while 7 cases are considered as special cases because the patients have non-tumour related medical conditions or side effects which affect the results. The decrease in the fractal dimensions with the deterioration of the patient conditions (in terms of disease progression) are attributed to the hierarchical localisation of the tracer which accumulates in the affected lesions and does not spread homogeneously throughout the body. Fractality emerges as a result of the migration patterns which the malignant cells follow for propagating within the body (circulatory system, lymphatic system). Analysis of the multifractal spectrum complements and supports the results of the fractal analysis. In the kinetic Monte Carlo modelling of the metastatic process a small number of malignant cells diffuse throughout a fractal medium representing the blood circulatory network. Along their way the malignant cells engender random metastases (colonies) with a small probability and, as a result, fractal spatial distributions of the metastases are formed similar to the ones observed in the PET/CT images. In conclusion, we propose that fractal and multifractal analysis has potential application in the quantification of the evaluation of PET/CT images to monitor the disease evolution as well as the response to different medical treatments.Comment: 38 pages, 9 figure

Early 18F-FDG PET/CT in COVID-19

We report the case of who has been hospitalized complaining about fever in the last 4 days. Laboratory data revealed lymphocytopenia and leucopenia with an elevation of C-reactive protein and positive real-time reverse transcription-polymerase chain reaction (RT-PCR). Six days before this hospitalization, when the patient was asymptomatic, 18F-FDG PET/CT images were performed for the therapeutic control of liver metastases of colorectal cancer. Lung abnormality findings at 18F-FDG PET/CT images, unrelated to cancer metastases, but suspicious for viral infection, may suggest the presence of COVID-19 disease in its early phase before symptoms onset. Since PET/CT is more sensitive than CT scan in detecting host’s reaction, the added value of this technique could be monitoring disease progression and could be used as a biomarker of lung disease activity and therefore as an important tool for a better understanding of the factors that contribute to the progression of lung disease

Texture Analysis in 18F-FDG Human PET/CT images

A jelen képalkotó diagnosztika feladata és felelőssége, hogy a betegről készült felvételből a lehető legtöbb információt kinyerje annak reményében, hogy ezen információk segítenek a megfelelő terápia kiválasztásában, esetleg a terápia hatásának nyomon követésében. Ehhez illeszkedik az a törekvés is, hogy PET/CT vizsgálatok esetén, a képen megjelenő tumor vagy lézió mintázatát is jellemezzük. A mintázat jellemzésére számos mennyiség áll rendelkezésre, amelyek prognosztikai értéke az ezzel a területtel foglalkozó kutatók fő kérdése. A doktori értekezés alapvetően egy kísérletes munkát mutat be, amely úgynevezett fantommérések alapján igyekszik vizsgálni a mintázat elemzés metodológiai kérdéseit. A mérések tervezése és kivitelezése során igyekeztünk olyan kísérleti elrendezést megvalósítani, amely lehetővé teszi, hogy eredményeink relevánsak maradjanak a humán vizsgálatok esetében is.A major objective of medical imaging is to maximize the extracted information from the diagnostic image, in the hope that any additional information can help the selection of the proper therapy, or support a more precise therapy monitoring. An attempt to this endeavour is to characterize the pattern of tumour or lesion, appearing in the image of PET / CT. There are a number of quantities available to characterize the pattern, but their prognostic value is not fully explored by researchers in this field. Beside the pitfalls related to biology, several doubts focusing on technical aspects. The doctoral dissertation basically presents an experimental work, which investigate the methodological questions of pattern analysis on the basis of so-called phantom measurements. During the design and implementation of the measurements, we tried to create an experimental arrangement that allows our results to remain relevant for human studies

Multiple hepatic lesions in a case of isolated hepatic tuberculosis simulating metastases on 18F-FDG PET/CT imaging

Hepatic tuberculosis is an unusual form of extrapulmonary tuberculosis and constitutes less than 1% of all cases of tuberculosis. Imaging studies for hepatic tuberculosis are nonspecific and mimic primary or metastatic carcinoma. Here we present 18F-FDG PET/CT images of a 25-year-old male patient with isolated hepatic tuberculosis

Right ventricular metastasis of leiomyosarcoma

Metastatic presentation of leiomyosarcoma in the heart is very rare. We present transthoracic echocardiography and combined PET/CT images of a case with a large right ventricular metastasis of leiomyosarcoma. The patient was placed on cytostatic drugs for palliative purposes, but passed away one month later because of an untreatable ventricular tackycardia