Time sensitivity-corrected retention index: an enhanced metabolic index from 18F-FDG PET to differentiate between benign and malignant pulmonary nodules.

The aim of the study was to evaluate pulmonary nodules (PNs) by incorporating time sensitivity (S) factor in the retention index (RI) and compare with the traditional fixed interval method. After obtaining approval from the Human Investigations Committee, 97 PNs from 81 patients (age=70±11) referred for dual-time fluorine-18 fluorodeoxyglucose PET (16.1±1.

Fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography predicts extrahepatic metastatic potential of colorectal metastasis: a practical guide for yttrium-90 microsphere liver-directed therapy.

The objective of this retrospective study was to assess the likelihood of extrahepatic metastases based on tumor metabolic load index (TMLI) for patients with colorectal liver metastases to determine the potential intermediate endpoint of yttrium-90 (Y-90) microsphere liver-directed therapy. Forty-eight (48) patients with colorectal metastatic cancer of the liver who were referred for Y-90 microsphere therapy and F-18 fluoro-2-deoxy-D-glucose positron emission tomography (PET) imaging were included. All patients had baseline computed tomography, hepatic angiography, and planning intra-arterial technetium-99m macro-aggregated albumin scans.

Volume-normalized uptake rates with robust transportability from PET dual-time and Patlak analyses.

Purpose: The intention here is to enhance the usefulness of the Gjedde-Patlak plot of dynamic positron emission tomography (PET) tracer uptake. Two additional parameters closely related to the physiologically significant and diagnostically useful phosphorylation rate k (3) are therefore studied. Additionally, their inter-institutional transportability is examined.

Time sensitivity: a parameter reflecting tumor metabolic kinetics by variable dual-time F-18 FDG PET imaging.

Objectives: The aim of this study was to define and investigate the time sensitivity of tumors by variable dual-time fluorodeoxyglucose positron emission tomography (FDG PET).

Methods: Variable dual-time (t) protocol (P) FDG PET-computed tomography (CT) scans from 40 patients with pathologically proven head and neck tumors without brain metastasis were analyzed. The first protocol (P.

Optimizing dual-time and serial positron emission tomography and single photon emission computed tomography scans for diagnoses and therapy monitoring.

Introduction: A region's early and late tracer uptake activities, QE and QL, within a dual-time scan (i.e. using two frames) or in serial scans (as for monitoring therapeutic response), are popular quantitative diagnostic aids, especially in oncology.

A weight index for the standardized uptake value in 2-deoxy-2-[F-18]fluoro-D-glucose-positron emission tomography.

Introduction: Known errors in the standardized uptake value (SUV) caused by variations in subject weights W encountered can be corrected by lean body mass or body surface area (bsa) algorithms replacing W in calculations. However this is infrequently done. The aims of the work here are: quantify sensitivity to W, encourage SUV correction with an approach minimally differing from tradition, and show what improvements in the SUV coefficient of variation (cv) for a population can be expected.

Investigating the existence of quantum metabolic values in non-Hodgkin's lymphoma by 2-deoxy-2-[F-18]fluoro-D-glucose positron emission tomography.

Objectives: To investigate the existence of quantum metabolic values in various subtypes of non-Hodgkin's lymphoma (NHL).

Methods: Fifty-eight patients with newly diagnosed NHL and positron emission tomography (PET) performed within three months of biopsy were included. The standardized uptake value (SUV) from PET over the area of biopsy and serum glucose [Glc] were recorded.

Regional yttrium-90 microsphere treatment of surgically unresectable and chemotherapy-refractory metastatic liver carcinoma.

Purpose: The aim of this prospective study was to assess the safety and tumor response of intra-arterial Y-90 microspheres for the treatment of surgically unresectable and chemotherapy-refractory liver metastases.

Materials And Methods: Forty-six (46) patients with metastatic cancer to the liver from various solid tumors, with tumor progression despite polychemotherapy, were included. All patients had baseline computed tomography (CT), 18-Fluoro-2-deoxy-D-glucose-positron emission tomography (F-18 FDG-PET), hepatic angiography, and intra-arterial Tc-99m macroaggregated albumin (MAA) scan for the assessment of extrahepatic aberrant perfusion and lung shunting fraction.

A statistical investigation of normal regional intra-subject heterogeneity of brain metabolism and perfusion by F-18 FDG and O-15 H2O PET imaging.

Background: The definite evaluation of the regional cerebral heterogeneity using perfusion and metabolism by a single modality of PET imaging has not been well addressed. Thus a statistical analysis of voxel variables from identical brain regions on metabolic and perfusion PET images was carried out to determine characteristics of the regional heterogeneity of F-18 FDG and O-15 H2O cerebral uptake in normal subjects.

Methods: Fourteen normal subjects with normal CT and/or MRI and physical examination including MMSE were scanned by both F-18 FDG and O-15 H2O PET within same day with head-holder and facemask.

Addressing glucose sensitivity measured by F-18 FDG PET in lung cancers for radiation treatment planning and monitoring.

Purpose: To address glucose sensitivity in lung cancers before and after radiation treatment (Tx).

Methods And Materials: Twelve patients were each studied with two pre-Tx positron emission tomography (PET) scans and 3 patients each with one post-Tx PET scan, with glucose concentration [Glc] and maximum standard uptake value (SUV) recorded. The pre-Tx glucose sensitivity, g from SUV1/SUV2= {[Glc]1/[Glc]2}g and Tx index, tau from SUVpost-Tx/SUVpre-Tx = {[Glc]post-Tx/[Glc]pre-Tx}tau was calculated by linear regression.

2-deoxy-2-[F-18]fluoro-D-glucose-positron emission tomography sensitivity to serum glucose: a survey and diagnostic applications.

Objective: The positron emission tomography (PET) clinical utility of the sensitivity (gamma) of uptake (Q) to a change in plasma glucose concentration (C) is investigated.

Methods: Gamma is obtained from data as [ln(Q (2)/Q (1))] / [ln(C(2)/C(1))], using previously published intrapatient studies varying C within a single patient and some interpatient ones. It can be theoretically related to the half-saturation constant in the Michaelis-Menten quantification of competitive uptake.

Glucose-normalized standardized uptake value from (18)F-FDG PET in classifying lymphomas.

Unlabelled: Our objective was to derive the best glucose sensitivity factor (g-value) and the most discriminating standardized uptake value (SUV) normalized to glucose for classifying indolent and aggressive lymphomas.

Methods: The maximum SUV obtained from (18)F-FDG PET over the area of biopsy in 102 patients was normalized by serum glucose ([Glc]) to a standard of 100 mg/dL. Discriminant analysis was performed by using each SUV(100) (SUV x {100/[Glc]}(g), calculated using various g-values ranging from -3.

Optimizing imaging time for improved performance in oncology PET studies.

Purpose: The potential for improving the diagnostic performance of static positron imaging tomography (PET) by judiciously choosing optimum post-injection imaging times is investigated.

Procedures: Dynamic and whole-body scan data, from 2-deoxy-2-[18F]fluoro-D-glucose (FDG) oncological studies, are analyzed for changing standardized uptake value (SUV) behavior with increasing post-injection times at either single- or multiple-bed positions. Model-based interpretations address d(SUV)/dt, shown to correlate with SUV, and the contrast ratio for a tumor and its surroundings.

Model Interpretation and Clinical Implications.

Useful characterizing parameters have been derived from historical positron emission tomography (PET) standardized uptake values (SUV) and influx constants K. Meta-analysis was performed on 30 multipatient PET oncological studies providing same patient SUVs and K's. Averaged results for fluorine-18 fluorodeoxyglucose (FDG) and L-methionine respectively were: SUV vs.

Cost Analysis of FDG PET for Managing Patients with Ovarian Cancer.

Monte Carlo simulation analysis was used to compare the cost of managing recurrent ovarian cancer patients with and without the use of positron emission tomography (PET) scanning. Assumptions in the management pathway were: (1) a positive PET scan led to either laparoscopy or laparotomy, followed by chemotherapy (true positive PET) or follow-up (false positive PET); (2) a negative PET scan resulted in continued follow-up (true negative PET) or laparotomy (false negative PET); and, (3) a laparotomy led to chemotherapy or follow-up. In this simulation, sensitivity and specificity of FDG PET for recurrent ovarian cancer varied from 72-91% (mean 83%) and 69-95% (mean 85%), respectively, as defined by the ROC curve.

Degree of fractal behavior as a diagnostic aid in quantitative image analyses.

Purpose: Multiple strategies in diagnoses of different diseases from images can include their histogram analyses. Any fractal behavior in the latter is to be quantified as to extent here, with a view toward contributing to a diagnostic process.

Procedure: One tool in quantitative image analyses is the fractal dimension D of the pixel histogram, a measure of self-similarity over various scales in a fitted power-law behavior of pixel intensity cumulative probability distribution.