The objectives of this study were to examine the effective dose range and the test-retest reliability of florbetapir F 18 using, first, visual assessment by independent raters masked to clinical information and, second, semiautomated quantitative measures of cortical target area to cerebellum standardized uptake value ratios (SUVr) as primary outcome measures. Visual ratings of PET image quality and tracer retention or beta-amyloid (A beta) binding expressed as SUVrs were compared after intravenous administration of either 111 MBq (3 mCi) or 370 MBq (10 mCi) of florbetapir F 18 in patients with Alzheimer's disease (AD) (n = 9) and younger healthy controls (YHCs) (n = 11). In a separate set of subjects (AD, n = 10; YHCs, n = 10), test-retest reliability was evaluated by comparing intrasubject visual read ratings and SUVrs for 2 PET images acquired within 4 wk of each other. Results: There were no meaningful differences between the 111-MBq (3-mCi) and 370-MBq (10-mCi) dose in the visual rating or SUVr. The difference in the visual quality across 111 and 370 MBq showed a trend toward lower image quality, but no statistical significance was achieved (t test; t(1) = -1.617, P = 0.12) in this relatively small sample of subjects. At both dose levels, visual ratings of amyloid burden identified 100% of AD subjects as A beta-positive and 100% of YHCs as A beta-negative. Mean intrasubject test-retest variability for cortical average SUVrs with the cerebellum as a reference over the 50- to 70-min period was 2.4% +/- 1.41% for AD subjects and 1.5% +/- 0.84% for controls. The overall SUVr test-retest correlation coefficient was 0.99. The overall k-statistic for test-retest agreement for A beta classification of the masked reads was 0.89 (95% confidence interval, 0.69-1.0). Conclusion: Florbetapir F 18 appears to have a wide effective dose range and a high test-retest reliability for both quantitative (SUVr) values and visual assessment of the ligand. These imaging performance properties provide important technical information on the use of florbetapir F 18 and PET to detect cerebral amyloid aggregates.

April 2008 Breast cancer is one of the most frequently diagnosed cancers in women, touching the lives of roughly 213,000 women in 2006. In addition to invasive breast cancer, approximately 62,000 cases of in situ breast cancer were projected to occur in 2006, with 85% of these being ductal carcinoma in situ. Even with these increased numbers, mortality is decreasing. Screening mammography has been the gold standard for breast cancer surveillance for 3 decades and is credited with decreasing mortality by 33%. Because mammography has resulted in earlier detection of breast cancer, more patients today are candidates for, and choose, breast-conserving surgery instead of mastectomy. However, mammography is frequently inadequate as a planning tool for lumpectomy. In addition, it has very limited value in women with dense breasts. This may explain the finding that residual cancer can be found in as many as 30% to 60% of patients after lumpectomy, resulting in a second trip to the operating room. One goal of molecular imaging is to preoperatively identify which patients are best served by lumpectomy and define the margins for surgery by identifying metabolic abnormalities in tissue, potentially decreasing the number of second surgeries needed for resection of residual disease. Any technology that could more precisely map the extent of both invasive and noninvasive disease would lead to more precise surgery. This article will review the history of molecular imaging in breast cancer with a special emphasis on the use of the new technology positron emission mamography (PEM), in preand postoperative breast cancer management.

We sought to prospectively assess the diagnostic performance of a high-resolution positron emission tomography (PET) scanner using mild breast compression (positron emission mammography [PEM]). Data were collected on concomitant medical conditions to assess potential confounding factors. At four centers, 94 consecutive women with known breast cancer or suspicious breast lesions received 18F-fluorodeoxyglucose (FDG) intravenously, followed by PEM scans. Readers were provided clinical histories and x-ray mammograms (when available). After excluding inevaluable cases and two cases of lymphoma, PEM readings were correlated with histopathology for 92 lesions in 77 women: 77 index lesions (42 malignant), 3 ipsilateral lesions (3 malignant), and 12 contralateral lesions (3 malignant). Of 48 cancers, 16 (33%) were clinically evident; 11 (23%) were ductal carcinoma in situ (DCIS), and 37 (77%) were invasive (30 ductal, 4 lobular, and 3 mixed; median size 21 mm). PEM depicted 10 of 11 (91%) DCIS and 33 of 37 (89%) invasive cancers. PEM was positive in 1 of 2 T1a tumors, 4 of 6 T1b tumors, 7 of 7 T1c tumors, and 4 of 4 cases where tumor size was not available (e.g., no surgical follow-up). PEM sensitivity for detecting cancer was 90%, specificity 86%, positive predictive value (PPV) 88%, negative predictive value (NPV) 88%, accuracy 88%, and area under the receiver-operating characteristic curve (Az) 0.918. In three patients, cancer foci were identified only on PEM, significantly changing patient management. Excluding eight diabetic subjects and eight subjects whose lesions were characterized as clearly benign with conventional imaging, PEM sensitivity was 91%, specificity 93%, PPV 95%, NPV 88%, accuracy 92%, and Az 0.949 when interpreted with mammographic and clinical findings. FDG PEM has high diagnostic accuracy for breast lesions, including DCIS.

Breast cancer is the most common female malignancy in Western countries. The limitations of mammography, ultrasound and MRI do not allow reliable identification of primary breast cancer at early stages. Functional breast imaging with positron emission tomography (PET) and F-18 fluorodeoxyglucose (FDG) enables the visualization of increased glucose metabolism of breast cancer. However, despite the successful identification of primary breast cancer, FDG-PET provides a low sensitivity to detect small tumors. Therefore, FDG-PET does not allow screening of asymptomatic women and cannot be used to exclude breast cancer in patients with suspicious breast masses or abnormal mammography. FDG-PET is a powerful tool for staging of breast cancer patients, but does not detect micrometastases and small tumor infiltrated lymph nodes. Nevertheless, in patients with locally advanced breast cancer, PET accurately determines the extent of disease, particularly the loco-regional lymph node status. Advances in technology, for example the development of dedicated breast imaging devices such as positron emission mammography, hold promise to improve the detection of primary tumors in the future.

A 40-year-old man experiencing early satiety, a 25-1b weight loss, and intermittent nausea underwent an esophagogastroduodenoscopy, which demonstrated an ulcerated mass of the stomach extending from 43 cm to 53 cm from the incisors occupying the gastroesophageal junction, gastric cardia, fundus, and body. A biopsy of the gastric body showed diffuse infiltration of the lamina propria by poorly differentiated signet-ring cell adenocarcinoma. F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) with computed tomography demonstrated minimally increased FDG uptake relative to normal tissues. Further study to determine the use of FDG PET in the evaluation of patients with gastric signet-ring cell carcinoma is warranted.

Purpose: Accurate delineation of the gross tumor volume (GTV) is important in radiation therapy treatment planning. We evaluated the impact of PET and endoscopic ultrasound (EUS) compared with CT simulation in the planning of radiation fields for patients with esophageal carcinoma.Material and Methods: Twenty-five patients presenting with esophageal carcinoma for radiation therapy underwent PET scans in the treatment position after conventional CT simulation. Patients underwent PET/CT scanning after being injected with 10 to 20 mCi of [F-18]-2-deoxy-2-fluro-D-glucose. The length of the abnormality seen on the CT portion of the PET/CT scan vs. the PET scan alone was determined independently by 2 separate investigators. The length of the GTV and detection of regional adenopathy by PET was also correlated with EUS in 18 patients. Of the 18 patients who had EUS, 2 had T2 tumors and 16 had T3 tumors. Eighteen patients had adenocarcinoma and 7 had squamous cell carcinoma. Nine tumors were located at the gastroesophageal junction, 8 at the lower esophagus, 7 in the middle esophagus, and 1 in the cervical esophagus. The PET scans were reviewed to determine the length of the abnormality by use of a standard uptake value (SUV) of 2.5 to delineate the tumor extent.Results: The mean length of the cancer was 5.4 cm (95% CI 4.4-6.4 cm) as determined by PET scan, 6.77 cm (95% CI, 5.6-7.9 cm) as determined by CT scan, and 5.1 cm (95% CI, 4.0-6.1 cm) for the 22 patients who had endoscopy. The length of the tumors was significantly longer as measured by CT scans compared with PET scans (p = 0.0063). EUS detected significantly more patients with periesophageal and celiac lymphadenopathy compared to PET and CT. The SUV of the esophageal tumors was higher in patients with peri-esophageal lymphadenopathy identified on PET scans.Conclusion: Endoscopic ultrasound and PET scans can add additional information to aid the radiation oncologist's ability to precisely identify the GTV in patients with esophageal carcinoma. (c) 2005 Elsevier Inc.

UNLABELLED:Prior studies have documented increased (18)F-FDG adrenal activity in both benign and malignant pathologic conditions. When whole-body PET imaging is performed without CT anatomic coregistration, however, the normal adrenal gland is difficult to recognize. The purpose of this study was to investigate the normal adrenal appearance and standardized uptake value (SUV) using (18)F-FDG PET/CT imaging. METHODS:Twenty patients with lymphoma with normal-appearing adrenal glands on prior CT examination (less than a 5% pretest likelihood of adrenal involvement) were studied. PET/CT imaging was performed 2 h after intravenous administration of (18)F-FDG. Unenhanced CT scans were acquired for attenuation correction and anatomic coregistration. PET images were reconstructed using an ordered-subsets expectation maximization algorithm and were corrected for body weight, dose, and radioactive decay. Ability to confirm visualization of the adrenal glands was determined for (18)F-FDG PET alone and for (18)F-FDG PET/CT by a consensus of 2 readers, and uptake of (18)F-FDG in the adrenal gland was compared with liver activity and scored visually (0 = no visualization, 1 = activity less than in liver, 2 = activity equal to liver activity, and 3 = activity greater than in liver). RESULTS:The 2 readers agreed on visualization of the adrenal glands with PET alone for 2 of 40 (5%) glands. With PET/CT, the readers agreed on visualization of 27 of 40 (68%) adrenal glands. Visual scores for normal adrenal activity ranged from 0 to 3, and maximum SUVs ranged from 0.95 to 2.46. Visual scoring of adrenal activity correlated well with both mean and maximal SUV (mean SUV vs. visual score: slope = 0.96, r = 0.88; maximum SUV vs. visual score: slope = 0.99, r = 0.87). CONCLUSION:PET/CT permits more reliable visualization of normal adrenal glands than does PET alone. Visual assessment of adrenal uptake correlates well with SUV measurement, and readers of PET/CT need to be aware of the wide range of normal adrenal uptake.

Background: Evaluation of high-risk mammograms represents an enormous clinical challenge. Functional breast imaging coupled with mammography (positron emission mammography [PEM]) could improve imaging of such lesions. A prospective study was performed using PEM in women scheduled for stereotactic breast biopsy. Methods: Patients were recruited from the surgical clinic. Patients were injected with 10 mCi of 2-[ 18 F] fluorodeoxyglucose. One hour later, patients were positioned on the stereotactic biopsy table, imaged with a PEM scanner, and a stereotactic biopsy was performed. Imaging was reviewed and compared with pathologic results. Results: There were 18 lesions in 16 patients. PEM images were analyzed by drawing a region of interest at the biopsy site and comparing the count density in the region of interest with the background. A lesion-to-background ratio >2.5 appeared to be a robust indicator of malignancy and yielded a sensitivity of 86%, specificity of 91%, and overall diagnostic accuracy of 89%. No adverse events were associated with the PEM imaging. Conclusions: The data show that PEM is safe, feasible, and has an encouraging accuracy rate in this initial experience. Lesion-to-background ratios >2.5 were found to be a useful threshold value for identifying positive (malignant) results. This study supports the further development of PEM.

The initial imaging evaluation of a patient with a suspected tracheal abnormality is the chest radiograph, which is poor for detection of central airway lesions. Prior to the development of CT, planar tomography was performed to better evaluate the deep layers of the chest. Tomography is rarely performed today for chest imaging. There have been major advances in chest radiography techniques secondary to improvements in electronics and computer technology that might ultimately improve plain film assessment of the central airways.

The purpose of the study was to demonstrate the feasibility of a hybrid functional/anatomic breast imaging platform with biopsy capability for facilitating lesion detection and diagnosis. This platform consists of an investigative dedicated positron emission mammography (PEM) device mounted on a stereotactic X-ray mammography system, permitting sequential acquisition of mammographic and emission images during a single breast compression. There is automatic coregistration of images from both modalities, and these results can be successfully correlated with histopathologic findings. The potential utility of functional images correlated to anatomic images would include noninvasively detecting clinically and radiographically occult cancers, assessing response to therapy, discriminating between benign and malignant breast masses, and ultimately reducing the number of invasive and costly surgical interventions. A spot-digital mammogram and subsequent PEM image, collected over a 4-minute period, were obtained in a single patient with the breast in compression after intravenous injection of (F-18)-2-deoxy-2-fluoro-D-glucose (FDG) at the time of stereotactic biopsy. The authors conclude that FDG-based lesion localization information may be combined with the lesion X-ray attenuation characteristics using this common imaging platform.

The purpose of this review is to underscore the value of positron emission tomography (PET) in the management of patients with soft tissue sarcomas. Although the most essential step in the diagnostic evaluation of soft tissue sarcomas is tumor biopsy, functional imaging techniques is growing and becoming more popular than before. PET scan traces molecular and cellular activities of normal and tumor cells through the use of radiotracers that engage in cell metabolism. The most important and widely used tracer is fluorodeoxyglucose ((18)FDG). PET scan usefulness is not limited to its ability to differentiate benign from malignant lesions. The scan can detect intralesional morphologic variation which is especially true in soft tissue sarcomas, it can predict tumor grade, and it is of value in staging, restaging and prognosis. As for the time, PET is not meant to replace tissue biopsy but rather complement the biopsy to better understand the biological behavior of soft tissue sarcomas.

Rounded atelectasis is a well recognized, benign cause of a pulmonary mass. While its radiographic features have been well characterized in the radiologic literature, they are not pathognomonic and patients are commonly biopsied. Positron emission tomography (PET) has become a powerful tool to distinguish between benign and malignant disease in the thorax. We present the CT and PET imaging features of three cases of biopsy proven rounded atelectasis.

BACKGROUND:Positron emission tomography (PET) is a means of imaging tissue based upon its metabolic activity. Initial studies in the field of oncology suggest that PET may be useful for diagnosis, staging, and treatment of various tumors.METHODS:Twenty-eight patients with 37 breast lesions were studied with PET using [fluorine-18] 2-deoxy-2-fluoro-D-glucose (FDG) to assess which clinicopathological characteristics relate to FDG accumulation by the primary tumor.RESULTS:PET-FDG was found to successfully discriminate malignant from benign breast lesions (p = 0.02) and identify axillary lymph node metastases. FDG uptake by the primary tumor was found to be independent of age, menopausal status, race, tumor size, laterality, histologic differentiation, ploidy, DNA index, estrogen or progesterone receptor value, pathologic stage, and serum glucose. Higher tumor nuclear grade and S-phase were associated with more FDG accumulation by the primary tumor compared with normal breast tissue. PET-FDG correctly identified five malignant lesions that were indeterminant for cancer both on clinical breast examination and mammography and identified one occult cancer that was neither palpable nor apparent mammographically. PET-FDG correctly identified clinical occult axillary metastatic cancer in five patients.CONCLUSIONS:This study shows that PET-FDG imaging can distinguish malignant from benign breast lesions among a diverse group of patients and suggests that PET-FDG may not only allow for preoperative staging of patients but also provide information about prognosis. This study provides impetus for continued research into PET-FDG imaging of breast lesions, which could have a major impact on the treatment of breast cancer.

Cardiac and respiratory motion during the long acquisition times required in 3d magnetic resonance imaging (MRI) can lead to excessive image degradation and consequently poor diagnosis and interpretation in the thoracic region. This paper addresses the issue of obtaining good image quality with 3d gradient echo (GE) imaging in the study of the pulmonary vascular system and its diseases. To study the pulmonary vascular system two approaches have been considered. First, a proton density/inflow weighted scan consisting of a syncopated 3d FLASH acquisition is used to provide a 3d pulmonary angiogram. Secondly, aT 1 weighted scan using 3d IR-FLASH (inversion recovery FLASH) helps in determining the presence of pulmonary emboli. Multiple acquisitions and rectangular field of view are utilized to pseudogate to the respiratory period in order to reduce motion artifacts while keeping reasonable imaging times. Technical aspects on data collection during the approach to equilibrium and acquisition strategies in the presence of thoracic motion and its impact on vessel resolution are addressed. The method has proven successful for imaging volunteers and, more recently, in obtaining useful clinical information.