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Barry M McCook

Publications and source records attributed to Barry M McCook.

9 recordsLinked to original sources
PubMed2006

Positron emission tomography/computed tomography: protocol issues and options.

Combined positron emission tomography/computed tomography (PET/CT) became FDA-approved for clinical use in late 2001. There are several design advantages of combined PET/CT over PET and CT acquired on separate devices, including more accurate CT and PET data co-registration, improved lesion localization, consolidation of imaging studies, and reduced scan times compared to dedicated PET. There are several protocols that can used to scan patients on combined PET/CT devices. Although there is no single "correct" protocol for performing a PET/CT scan, the use of oral and intravenous contrast media may improve the diagnostic value of the CT component. Whether to utilize contrast media depends on important clinical variables, including the specific type of tumor and the likelihood of encountering viable abdominal and pelvic malignancy. This article discusses various protocols pertinent to PET/CT imaging, including how the CT portion of a PET/CT scan can be performed and optimized, as well as PET/CT interpretation and reporting issues.

Artifacts↗
PubMed2005

Controversial ectopic thyroid: a case report of thyroid tissue in the axilla and benign total thyroidectomy.

A 43-year-old woman presented with a mass in her left axilla, which was surgically excised. Histologically, the tissue was a reactive lymph node with adjacent thyroid follicular tissue. The differential diagnosis included benign ectopic thyroid versus metastatic well-differentiated follicular-derived thyroid carcinoma. Because of the possibility of carcinoma, the patient underwent a diagnostic total thyroidectomy. The thyroid was grossly normal with no histologic evidence of malignancy. Post-operatively, the patient underwent a whole body 131I scan. Aside from an expected residual uptake in the thyroid bed region, there was no extrathyroidal uptake to suggest additional ectopic thyroid tissue or metastatic disease. At the time of this scan, her thyrotropin (TSH) was 92.8 microU/mL, thyroglobulin was less than 0.3 ng/mL, and thyroglobulin antibody was less than 3 IU/mL. Abnormalities in the embryologic development and migration of the thyroid gland can result in ectopic thyroid tissue. The most frequent locations are along the midline from the base of the tongue to the mediastinum. Only rare case reports exist of ectopic thyroid in other locations, including the chest (heart, trachea), abdomen (liver, gallbladder, pancreas), and pelvis (vagina). This case represents the first description of thyroid tissue in the axilla with a histologically benign thyroid gland.

Adult↗
PubMed2004

Diffuse bone marrow uptake on whole-body F-18 fluorodeoxyglucose positron emission tomography in a patient taking recombinant erythropoietin.

F-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET) is used extensively in oncology to diagnose, stage, and restage patients with various malignancies. Many patients treated for malignancies develop neutropenia secondary to marrow suppressive chemotherapy and are subsequently treated with synthetic hematopoietic growth factors (HGF), both granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte-colony-stimulating factor (G-CSF). Patients taking HGF can present a diagnostic challenge for those interpreting PET because they can demonstrate diffuse marrow uptake on FDG-PET scans, mimicking diffuse bone marrow metastases. It has not been reported whether bone marrow uptake is affected on PET scans in patients taking erythropoietin, the erythroid-specific cell-line stimulator. We report a case of extensive diffuse bone marrow uptake in a 77-year-old man with a history of colon cancer who began taking erythropoietin 3 weeks before his PET scan. This case demonstrates the need to consider erythropoietin in the differential diagnosis of possible etiologies causing diffuse bone marrow uptake on PET scans.

Aged↗
PubMed2003

Prevalence effect in a laboratory environment.

PURPOSE: To measure observer performance at various levels of prevalence. MATERIALS AND METHODS: A multiobserver multiabnormality receiver operating characteristic (ROC) study to assess the effect of prevalence on observer performance was conducted. Fourteen observers, including eight faculty members, two fellows, and four residents, interpreted 1,632 posteroanterior chest images with five prevalence levels by using a nested study design. Performance comparisons were accomplished by using a multireader multicase approach to assess the effect of prevalence from 28% (69 of 249) to 2% (31 of 1,577) on diagnostic accuracy. The mean times required to review and report a case were analyzed and compared for different levels of prevalence and readers' experience. RESULTS: Area under the ROC curve demonstrated that, with the study experimental conditions, no significant effect could be measured as a function of prevalence (P >.05) for any abnormality, group of cases, or readers. There were no significant differences (P >.05) in the mean times required to review and report cases at different prevalence levels and with different groups of readers. CONCLUSION: The consistency in the results and the size of this study suggest that with laboratory conditions, if a prevalence effect exists, it is quite small in magnitude; hence, it will not likely alter conclusions derived from such studies.

Laboratories↗
PubMed2002

Physiologic uterine uptake of FDG during menstruation demonstrated with serial combined positron emission tomography and computed tomography.

F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) has been used extensively to stage, restage, and follow neoplastic disease. However, focal accumulation of FDG may cause false-positive results in certain physiologic conditions. In this report, a unique PET and computed tomography (CT) combination scan helped define physiologic accumulation of FDG in the uterus during menstruation in a 40-year-old woman with a history of rectal melanoma and possible recurrent disease. An initial PET study, performed during menstruation, was followed immediately by a PET-CT scan, which showed marked accumulation of FDG in the posterior pelvis, localized to a retroverted uterus. An FDG PET-CT scan repeated 2 weeks later confirmed resolution of this "lesion." Thus, combined PET-CT correctly differentiated physiologic FDG uptake in a retroverted uterus from recurrent rectal melanoma. This case shows that physiologic FDG accumulation in the uterus should be considered when focal FDG accumulation is observed in the pelvis in women of reproductive age.

Adult↗
PubMedDate not supplied

An introduction to PET-CT imaging.

Cancer is one of the leading causes of morbidity and mortality in developed countries such as the United States. Complex clinical decisions about treatment of oncologic patients are largely guided by imaging findings, among other factors. Most radiologic procedures map the anatomy and morphology of tumors with little or no information about their metabolism. Positron emission tomography (PET) performed with 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) has proved valuable in providing important tumor-related qualitative and quantitative metabolic information that is critical to diagnosis and follow-up. PET-computed tomography (CT) is a unique combination of the cross-sectional anatomic information provided by CT and the metabolic information provided by PET, which are acquired during a single examination and fused. FDG PET-CT offers several advantages over PET alone; the most important is the ability to accurately localize increased FDG activity to specific normal or abnormal anatomic locations, which may be difficult or even impossible with PET alone. Understanding the principles of FDG PET-CT and the optimal scanning techniques and recognizing the potential pitfalls and limitations are important for advantageous use of this imaging modality.

Adult↗
PubMedDate not supplied

Combined PET-CT in the head and neck: part 1. Physiologic, altered physiologic, and artifactual FDG uptake.

Positron emission tomography (PET) with 2-[fluorine-18] fluoro-2-deoxy-D-glucose (FDG) has been effective for the diagnosis, staging, and restaging of malignancies of the head and neck region. However, lack of anatomic landmarks, variable physiologic uptake, and asymmetric FDG distribution in several altered physiologic states can confound image interpretation. In addition, many benign causes and several artifacts can simulate physiologic or pathologic FDG uptake in the head and neck. Combined PET-computed tomography (CT) is a unique imaging modality that permits anatomic and functional imaging on a single scanner with nearly perfect coregistration. Combined PET-CT provides information that cannot be obtained with PET or CT alone. In particular, PET-CT facilitates the interpretation of FDG uptake in the head and neck, an area that is characterized by dense and complex anatomic structures. An atlas of FDG uptake in this anatomic region was compiled on the basis of combined PET-CT findings in 11,000 patients. In general, patterns of FDG uptake were variable and often reflected patient activity during or immediately preceding the uptake phase. With the growing interest in PET-CT, interpreting radiologists and nuclear medicine physicians must be familiar with the patterns of FDG uptake in the head and neck to avoid misinterpretation or mis-diagnosis.

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