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Purpose Recently developed digital positron emission tomography/computed tomography (PET/CT) scanners (digital PET [dPET]) have given new dimensions to molecular imaging. dPET scanner has very high sensitivity, spatial resolution, and image contrast that leads to increased uptake of signal in small-volume structures like pituitary gland (PG) making them visible on PET/CT scan even in absence of any pathology. Adequate knowledge of physiological fluoro-2 deoxy D glucose uptake in PG is required in interpretation of dPET for correct diagnosis and reducing unnecessary additional imaging. The aim of this study is to evaluate the frequency of physiological PG uptake on dPET. Material and Methods Eighty-eight subjects (mean age, 54.44 ± 14.18 years; range, 26-84 years; 63 females and 25 males) with normal PG on magnetic resonance imaging brain and imaged within 6 months on dPET were included in this research study. Out of 88 patients, 20 control subjects (mean age, 58.15 ± 11.08 years: 15 females and 5 males) underwent PET/CT on conventional PET. All images were acquired with similar and standard acquisition protocol and reconstruction done with Time of flight with Point spread function. PG uptake was compared visually and quantitatively. Results PG uptake was seen in 43 patients (48.8%). Out of 43 patients, 31 (72%) showed low uptake, 11 (26%) showed intermediate grade of uptake, and 1 patient (2%) showed intermediate-to-high uptake and was categorized as high-grade uptake. In the control group of 20 patients, 3 (15%) showed low uptake, while none of them showed intermediate or high uptake. Conclusion Physiological PG uptake is commonly seen on dPET. Low-to-intermediate grade of PG uptake on dPET in an asymptomatic patient is physiological and does not require further evaluation and should be reported with caution.
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PURPOSE: Detection of osseous metastases by imaging can be challenging in patients with invasive lobular breast cancer (ILC). ILC may demonstrate low metabolic rate due to lower tumor cell density, decreased proliferation rate, diffuse infiltration of surrounding tissue, and low level of GLUT-1 expression. The aim of this study is to assess the diagnostic accuracy of 18F-FDG PET/CT in identifying bone metastases in ILC patients. MATERIAL AND METHODS: Out of 52 individuals diagnosed with lobular breast cancer and underwent 18F-FDG PET/CT for evaluation of metastases, 21 patients were included in our study population after applying inclusion and exclusion criteria. The radiological and clinical follow-up of at least 6â months served as the reference standard comparator. RESULTS: Bone metastases were confirmed in six patients. 18F-FDG PET/CT was true positive in two and false negative in four patients. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 18F-FDG PET/CT were 33.33, 93.33, 66.67, 77.78, and 76.19%, respectively (95% confidence interval). The tendency of ILC osseous metastases to be more sclerotic explains the low diagnostic accuracy of 18F-FDG PET/CT in detection of bone metastases, making it a less suited method of evaluation. CONCLUSION: The results of the present study indicate that 18F-FDG PET/CT has a low diagnostic accuracy in detecting bone metastases in lobular breast cancer and, by inference, new functional modalities can be explored in these patients. The findings contribute valuable insights to optimize the integration of molecular imaging into the diagnostic algorithm for this specific breast cancer subtype.
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ABSTRACT: Pulmonary hamartoma is the most common benign tumor of the lung and often discovered incidentally on imaging. We report the case of a 49-year-old woman recently diagnosed with left breast cancer with suspicious left axillary lymph nodes. 18 F-FDG PET/CT showed well-circumscribed, lobulated, low-attenuation soft tissue mass in the right lower lobe lung with mild to no significant metabolic activity. CT-guided biopsy showed the lesion composed of fat, cartilage, and smooth muscle, admixed with fibroconnective tissue. The findings are consistent with pulmonary hamartoma. The presence of fat in a well-circumscribed solitary pulmonary nodule along with low metabolic activity helps in the characterization of the lesion, which can alter patient management.
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Hamartoma , Neoplasias Pulmonares , Femenino , Humanos , Persona de Mediana Edad , Tomografía Computarizada por Tomografía de Emisión de Positrones , Fluorodesoxiglucosa F18 , Tomografía de Emisión de Positrones/métodos , Neoplasias Pulmonares/diagnóstico por imagen , Hamartoma/diagnóstico por imagen , Hamartoma/patologíaRESUMEN
One of the major issues in time-critical medical applications using wireless technology is the size of the payload packet, which is generally designed to be very small to improve the transmission process. Using small packets to transmit continuous ECG data is still costly. Thus, data compression is commonly used to reduce the huge amount of ECG data transmitted through telecardiology devices. In this paper, a new ECG compression scheme is introduced to ensure that the compressed ECG segments fit into the available limited payload packets, while maintaining a fixed CR to preserve the diagnostic information. The scheme automatically divides the ECG block into segments, while maintaining other compression parameters fixed. This scheme adopts discrete wavelet transform (DWT) method to decompose the ECG data, bit-field preserving (BFP) method to preserve the quality of the DWT coefficients, and a modified running-length encoding (RLE) scheme to encode the coefficients. The proposed dynamic compression scheme showed promising results with a percentage packet reduction (PR) of about 85.39% at low percentage root-mean square difference (PRD) values, less than 1%. ECG records from MIT-BIH Arrhythmia Database were used to test the proposed method. The simulation results showed promising performance that satisfies the needs of portable telecardiology systems, like the limited payload size and low power consumption.