The effect of age, menopausal state, and breast density on (18)F-FDG uptake in normal glandular breast tissue.

UNLABELLED: Theoretically, the degree of (18)F-FDG uptake in the glandular tissues of the normal breast can affect the detection of breast cancer. The aim of this prospective study was to investigate relationships among age, menopausal state, and breast density and determine whether they affect (18)F-FDG uptake in normal glandular breast tissue. METHODS: Among 250 newly diagnosed breast cancer patients, 149 patients (mean age +/- SD, 50.9 +/- 9.70 y; range, 32-77 y) were analyzed because they had normal contralateral breasts confirmed by MRI, mammography, and (18)F-FDG PET examinations. PET images were acquired 60 +/- 2 min after the administration of (18)F-FDG (5.2 MBq/kg of body weight). The maximum and average standardized uptake value (SUVmax and SUVavg, respectively) of (18)F-FDG were calculated in the normal breast. Patients were divided into groups according to qualitative breast density and menopausal state. Descriptive statistics and 2-factorial analysis of covariance were used to assess the effects of qualitative breast density, menopausal state, and age on SUVmax and SUVavg. Pearson chi(2) was used to test the relationship between menopausal state and qualitative breast density. RESULTS: The average age of patients with nondense breasts was significantly higher than that of patients with dense breasts (P < 0.01). Also, breast density related to menopausal state (P < 0.05). Dense breasts had an average SUVmax of 1.243 and mean SUVavg of 0.694, whereas nondense breasts had a mean SUVmax of 0.997 and mean SUVavg of 0.592. Analysis of covariance indicated that density and the linear effect of age were significant with regard to both SUVmax and SUVavg. After removing the linear effect of age, menopausal state had no effect on SUVmax and SUVavg. CONCLUSION: (18)F-FDG uptake significantly decreases as age increases and breast density decreases. Age and qualitative breast density are independent factors and significantly affect (18)F-FDG uptake for both SUVmax and SUVavg. Menopausal state had no effect on SUVmax and SUVavg.

Potential of dual time point FDG-PET imaging in differentiating malignant from benign pleural disease.

AIM: The aim of this study was to assess the utility of dual time point 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) imaging in differentiating benign from malignant pleural disease. METHODS: Fifty-five consecutive patients of suspected malignant pleural mesothelioma (MPM) and recurrence of MPM who were referred for the evaluation underwent two sequential 18F-FDG-PET scans (dual time point imaging). The average percent change in the maximum standardized uptake values (Delta%SUVmax) of the lesion/lesions between time point 1 (SUV(max1)) and time point 2 (SUV(max2)) was calculated. All PET results were correlated with the histopathological or cytopathology results. Patients were divided into three principal groups (A = newly diagnosed MPM, B = recurrent MPM, and C = benign pleural disease). The parameters of 18F-FDG uptake (SUV(max) values and its changes over time) were compared among groups. RESULTS: Among the 55 patients who had undergone dual time point 18F-FDG-PET studies, 44 were diagnosed with MPM (28 newly diagnosed and 16 had recurrence). The PET studies demonstrated 229 malignant pleural lesions in these patients. The remaining 11 patients were proven to have benign pleural disease. The mean +/- SD of the SUV(max1), SUV(max2), and the Delta%SUV(max) of the all lesions of each patient in groups A, B, and C were 5.0 +/- 2.2%, 5.8 +/- 2.8%, and 12.8 +/- 8.4%; 4.6 +/- 1.7%, 5.3 +/- 2.0%, 13.8 +/- 9.2%; and 1.6 +/- 0.4%, 1.4 +/- 0.3%, and-9.6 +/- 19.1%, respectively. The mean +/- SD of the SUV(max1), SUV(max2), and Delta%SUV(max) in patients with both newly diagnosed and recurrent MPM were significantly higher than those of benign pleural disease group (p < 0.0001). For each patient, the most intense (hottest) lesion's SUV(max1), SUV(max2), and Delta%SUV(max) were also compared among the aforementioned groups, and these results again confirmed that MPM lesions had significantly higher values than those of benign pleural lesions (p < 0.0001). CONCLUSIONS: There is an increasing uptake of (18)F-FDG over time in pleural malignancies, whereas the uptake in benign pleural disease generally stays stable or decreases over time. Therefore, dual time point imaging appears to be an effective approach in differentiating benign from malignant pleural disease, which increases the sensitivity and is also helpful in guiding the biopsy site for a successful diagnosis.

Usefulness of non attenuation corrected 18F-FDG-PET images for optimal assessment of disease activity in patients with lymphoma.

This study aimed at determining whether non attenuation corrected (NAC) positron emission tomography (PET) images, in addition to the attenuation corrected (AC) PET images, should be included in the interpretation of fluoro-18 fluorodeoxyglucose ((18)F-FDG-PET) images in patients with lymphoma. The study included 58 patients, 35 males 23 females, mean age 55+/-16 years. There were 64 superficial and 170 deep lymph node (LN) lesions. Lesion detection, uptake intensity using a three-point scale (1-mild, 2-moderate, 3- intense) and overall clarity of each lesion were compared on both PET images. Our results showed that the detection rate for superficial LN was 100% for NAC-PET and 98.4% for AC-PET images. The degree of (18)F-FDG uptake (intense, moderate and mild uptake) was 56.3%, 31.3% and 12.5% for NAC-PET images and 23.4%, 34.4% and 40.6% for AC-PET images, respectively. The overall image clarity was significantly in favor of NAC compared to AC-PET images (89% vs 20%, P<0.01). For deep LN, lesions, detection rate was for NAC and AC-PET images 95.3% and 99.4%, respectively. (18)F-FDG uptake intensity (intense, moderate and mild uptake) was 42.4%, 27.1% and 25.9% for NAC and 52.4%, 43% and 4.1% for AC-PET images, respectively. The overall image clarity for AC-PET images was superior to NAC-PET images (81.8% vs 53% P=0.01). In conclusion, NAC-PET images appeared to be superior to AC-PET images in detecting superficial LN lesions. AC-PET images are superior to NAC-PET images with regard to the deep-seated LN lesions. Therefore, AC and NAC-PET images are complimentary to each other and require to be reviewed together in the evaluation of patients with lymphoma.

Receptor Imaging in Patients with Breast Cancer.

With advances in gene microarray technologies, the classification of breast cancers has been revised to take into account new information based on common genetic factors that are associated with clinically significant subgroups. At present, breast cancer is divided into 4 major subgroups, Luminal A, Luminal B, HER2/neu positive, and Basal-like. Many breast cancer researchers believe that this classification scheme will change with further subdivision of these categories in various prognostic subgroups. The presence of hormone or growth factor receptors is a key factor in the current classification. Beyond their interest as biomarkers associated with specific subgroups of breast cancer, the expression of receptors in breast cancer has profound therapeutic implications. Given the importance of these receptors in the management of breast cancer, many receptor-binding radiotracers have been developed over the past 30 years. In this article, the current status of receptor-binding radiotracers in breast cancer is reviewed.

Exploring Tumor Biology with Fluorodeoxyglucose-Positron Emission Tomography Imaging in Breast Carcinoma.

This article reviews the promising application of fluorodeoxyglucose-positron emission tomography (FDG-PET) imaging in exploring tumor biology of breast carcinoma based upon the authors' experience and also reviews current literature on this topic. The interest in this novel aspect of breast PET imaging has gained momentum in recent years as more is understood about the molecular subtypes and heterogeneous behavior of breast cancer. With the development of newer targeted therapies, oncologists are realizing the need for a means of accurate prediction and assessment of treatment response early in the course of therapy. Hence the studies on FDG-PET imaging in exploring the tumor biology of breast carcinoma have focused on: tumor histologic subtypes, hormonal receptor expression, disease burden at diagnosis, tumor proliferation index, and other molecular parameters. The correlation of various PET tracer parameters (eg, 15O-water PET-derived blood flow measurements and 18F-FDG-PET derived glucose metabolism rate parameters) is also of considerable interest. To summarize, the utility of FDG-PET/CT imaging on this aspect of breast carcinoma imaging holds considerable promise in disease characterization, and it can be foreseen that it will soon aid in guiding and adapting newer therapeutic regimens.

Role of [F-18] 2-Deoxy-2-Fluoro-d-Glucose PET and PET/CT in Staging and Follow-Up of Breast Cancer.

The precise role of PET/CT (computed tomography) continues to evolve, although 20 years have passed since the first study using (18)F 2-Deoxy-2-Fluoro-d-Glucose (FDG)-PET for the assessment of breast cancers. The current whole body PET/CT devices have not achieved adequate accuracy to replace conventional imaging methods and histopathology. Despite the fact that high positive predictive value of FDG-PET and PET/CT in diagnosis of axillary lymph node involvement can avoid sentinel node biopsy in a fraction of metastatic patients, FDG-PET has been shown to be of limited value in staging of axillary lymph node involvement. The current literature demonstrates that FDG-PET and PET/CT are considerably superior compared with conventional methods for the assessment of extra-axillary regional lymph node metastases such as internal mammary and mediastinal lymph nodes. Also, FDG-PET or PET/CT is the preferred method to assess the extent of distant metastatic disease and to diagnose patients with suspicion of recurrent or metastatic disease. Technological developments in positron emission mammography, PET/CT, and PET/MRI have great potential for better diagnosis, staging, and re-staging in patients with breast cancer in the near future.

Central photopenic lesions on FDG-PET scan in a patient with peripheral T cell lymphoma.

Central necrosis in lymphoma lesions as demonstrated in [(18)F] fluoro-2-deoxyglucose positron emission tomography (FDG-PET) studies is a rare phenomenon, and the clinical significance of this observation has not been described in the literature. The role of FDG-PET in the management of peripheral T cell lymphoma (PTCL) is also still unclear at this time. We present a case of a patient newly diagnosed with PTCL who underwent both computed tomography (CT) and FDG-PET examinations prior to and following therapy. CT showed pulmonary cavitary lesions in both lungs, and PET demonstrated multiple large confluent masses with intense FDG uptake in the corresponding lung fields with central photopenia suggestive of necrosis. Post-treatment FDG-PET images showed a significant improvement in the previously described lesions with some residual, recurrent, and new lesions. Central necrosis shown by PET may be associated with the advanced stage of the disease and may have prognostic implications because of central necrosis caused by hypoxia.

Comparison of triple-negative and estrogen receptor-positive/progesterone receptor-positive/HER2-negative breast carcinoma using quantitative fluorine-18 fluorodeoxyglucose/positron emission tomography imaging parameters: a potentially useful method for disease characterization.

BACKGROUND: This study was designed to investigate the fluorine-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET) imaging characteristics of triple-negative (estrogen receptor-negative [ER-]/progesterone receptor-negative [PR-]/HER2-negative [HER2-]) breast carcinoma and compare the results with characteristics of ER+/PR+/HER2- breast carcinomas, which usually carry a favorable prognosis. METHODS: Patients with newly diagnosed breast carcinoma who had undergone dual-time-point FDG-PET before any therapeutic intervention and were identified as either ER-/PR-/HER2- or ER+/PR+/HER2- (the control group) on histopathology of the surgical specimen, were considered candidates for inclusion in this analysis. These patients underwent FDG-PET as a component of a prospective study that evaluated the role of multimodality imaging for characterizing primary breast lesions and locoregional staging. Breast cancer lesions were imaged twice at approximately 63 minutes and 101 minutes after the administration of FDG. Maximum standardized uptake values (SUVmax) were measured at both time points (SUVmax1 and SUVmax2) to analyze the data generated. After FDG-PET imaging, the patients underwent either breast-conserving surgery or mastectomy, and histopathology reports were used to provide the definitive diagnosis against which the PET study results were compared. RESULTS: In total, 88 patients with breast cancer (29 patients with 'triple-negative' breast cancer and 59 patients with ER+/PR+/HER2- breast malignancies) were selected among 206 individuals who were enrolled in the study protocol. The 'triple-negative' group comprised 14.08% of the total study population. The age of the patients with this subtype of tumor ranged from 33 years to 75 years (mean age+/-standard deviation, 51.6 +/- 10.1 years), and tumors in this subgroup ranged in size from 0.9 cm to 6 cm (mean size, 1.99 cm). Among the histopathologic subtypes, 25 tumors were infiltrating ductal carcinoma (86%), and 1 tumor each (3.5% each subtype) was lobular, mixed ductal-lobular, medullary, and tubular. For the calculation of FDG-PET parameters in this group, only patients who had undergone FDG-PET studies before any intervention were considered, and 18 patients in the triple-negative group met this criterion. According to same criterion, a control group of 59 patients with ER+/PR+/HER2- cancer who had focal FDG uptake were selected for comparison with the triple-negative population. The breast cancer lesions were observed as areas with focally enhanced uptake of FDG in all patients (sensitivity, 100%) in the triple-negative group. The mean (+/-standard deviation) SUVmax1 of the primary lesion for the triple-negative group was 7.27 +/- 5.6, the mean SUVmax2 was 8.29 +/- 6.4, and the percentage change in SUVmax (%DeltaSUVmax) was 14.3 +/- 15.8%. In the control group of 59 patients with ER+/PR+/HER2- breast carcinoma, the mean values for SUVmax1, SUVmax2, and %DeltaSUVmax were 2.68 +/- 1.9, 2.84 +/- 2.2, and 3.7 +/- 13.0%, respectively. The mean values for SUVmax1, SUVmax2, and %Dgr;SUVmax in the triple-negative group were significantly higher compared with the values in the nontriple-negative control group (P = .0032, P = .002, and P = .017, respectively). When the 2 subgroups were compared according to tumor size, grade, and stage, the SUVmax1 was significantly higher in the triple-negative group for both size categories (5.4 vs 1.9, P = .006; and 9.2 vs 3.5, P = .04) and for grade 3 tumors (9.1 vs 3.9, P = .022). The %DeltaSUVmax values for patients in the triple-negative group who had tumors that measured < or =2 cm and > 2 cm were 14.8 and 13.8, respectively; and the corresponding values for patients in the control group were 0.6 and 6.7, respectively. Although the mean %DeltaSUVmax clearly was higher in the triple-negative group for both tumor size categories, comparison between the 2 groups demonstrated a statistically significant difference in tumors that measured < or =2 cm (P = .016). The authors also observed that, in the triple-negative group, tumor grades were correlated significantly with the magnitude of SUVmax1 and SUVmax2 (P = .012 and P = .01, respectively). Stage for stage, tumors from the triple-negative group appeared to have a higher mean SUVmax1 compared with tumors from nontriple-negative control group. However, the trend reached statistical significance in patients with stage II disease. CONCLUSIONS: Triple-negative breast tumors were associated with enhanced FDG uptake commensurate with their aggressive biology and were detected with very high sensitivity by using FDG-PET imaging.

Impact of FDG PET on the preoperative staging of newly diagnosed breast cancer.

PURPOSE: The main objective of this study was to determine the efficacy of (18)F-fluorodeoxyglucose positron emission tomography (FDG PET) to assess the impact of this technique in staging of patients with newly diagnosed breast cancer. METHODS: Two hundred and seventy-one consecutive patients (median age = 51 +/- 11 years) with biopsy-proven primary breast cancer who were examined by FDG PET were enrolled in this prospective preoperative staging study. Whole-body FDG-PET images were acquired approximately 60 min after the intravenous administration of FDG (5.2 MBq/kg). Visual assessment and the maximum standardized uptake value (SUVmax) of breast lesions for semiquantitative analysis were carried out. The PET results were compared with the histopathology results. RESULTS: For the tumor, node, metastases (TNM) staging, 240 patients (250 breasts) were considered eligible based on the criteria that were established for this analysis. Significant differences were noted in SUVmax of lesions according to the TNM staging (p < 0.05). The average SUVmax of the primary tumor was calculated in patients with axillary involvement (n = 58) and for the ones without axillary metastasis (n = 79), and SUVmax were 4.1 +/- 3.5 and 2.8 +/- 2.3, respectively, with a significant difference between the two groups (p = 0.03). PET imaging revealed pathological FDG uptake in 54% (46/85) of patients with axillary lymph node metastases. The sensitivities of FDG PET for detecting axillary lymph node metastasis were found 41% in pN1, 67% in pN2, and 100% in pN3, and the specificity was 89% for pN0 stage. Detection of extra-axillary regional node or distant metastatic lesions revealed by PET scan in 22 of 24 patients resulted in a significant change in the TNM stage. Distant metastasis without axillary lymph node metastasis was noted in 21% (5/24) of patients. The results revealed that FDG PET upgraded TNM stage in 9.2% (22/240) of patients and 7.5% (18/240) of patients were diagnosed as having one or more distant metastases. CONCLUSION: FDG PET was able to identify extra-axillary regional nodal and distant lesions in newly diagnosed patients with breast cancer; FDG PET may alter the staging and management of therapy in patients with newly diagnosed breast cancer.

Implications of standardized uptake value measurements of the primary lesions in proven cases of breast carcinoma with different degree of disease burden at diagnosis: does 2-deoxy-2-[F-18]fluoro-D-glucose-positron emission tomography predict tumor biology?

OBJECTIVES: Tumor glycolytic activity as determined by 2-deoxy-2-[F-18]fluoro-D-glucose-positron emission tomography (FDG-PET) imaging is an important marker of tumor biology and provides critical information about the behavior of most malignancies at different stages of the disease. This study was undertaken to determine whether the degree of FDG uptake differs between the primary breast lesions with varying disease burden at diagnosis in proven cases of breast carcinoma. MATERIALS AND METHODS: Among 250 patients enrolled for this prospective study, 174 patients with newly diagnosed breast carcinoma at different disease stages who had undergone dual time point FDG-PET before any therapeutic or surgical interventions were considered for inclusion in this analysis. These patients prospectively underwent multimodality imaging techniques, such as magnetic resonance imaging (MRI), ultrasonography, digital mammography, computed tomography (CT), and dual time point FDG-PET, as a component of a National Institutes of Health-funded project for characterizing primary breast lesions and local-regional staging. The slice with maximum FDG uptake in the region of interest (ROI) was chosen for the first time point and the second time point images for quantitative measurement of the metabolic activity of the tracer (SUVmax1 and SUVmax2, respectively). Furthermore, the percent change in SUVmax (%DeltaSUVmax) between SUVmax1 and SUVmax2 was calculated. RESULTS: The patient population (n=174) were divided into three groups for the purposes of this study. Sixty-four patients with primary and metastatic axillary lymphadenopathy (designated as group I) and 18 patients with both axillary and distant metastases (designated as group II) met the inclusion criteria for this analysis. The third group (group III) comprised of a population of 92 patients without any metastasis either at the lymph nodes or at distant sites. The mean SUVmax1, SUVmax2, and the %DeltaSUVmax in the early and delayed FDG-PET in group I (n=64) patients were as follows: primary lesion 4.8+/-3.9, 5.3+/-4.5, and 9.4+/-12.8%, respectively, and axillary lesions 3+/-2.6, 3+/-2.7, and 1.1+/-21.3%, respectively. Among the group II patients (n=18), the mean values of the primary lesion with regard to the SUVmax1, SUVmax2, and the %DeltaSUVmax were 7.7+/-6.2, 8.9+/-7.1, and 15.7+/-10.8%, respectively. The corresponding figures for the axillary lesions were 3.5+/-3.1, 3.7+/-3.1, and 6.3+/-20.9%, respectively, and those for the distant metastatic lesions were 3+/-1.4, 3.1+/-1.2, and 8.5+/-21.2%, respectively. The mean SUVmax1, SUVmax2, and the %DeltaSUVmax of the primary lesion of group III patients (n=92) without any metastasis were 2.9+/-2.7, 3.4+/-2.4, and 4.5+/-4.2%, respectively. Unifactorial ANOVA of the three parameters among the primary lesions of these three groups were statistically significant with regard to the mean SUVmax1 (p=0.01) and SUVmax2 (p=0.01). These values in the primary lesions were highest in group II (those with both axillary and distant metastases), followed by group I (those with only metastatic axillary adenopathy) and group III (patients without any metastasis), and could be related to the more aggressive tumor biology in group II. CONCLUSION: The findings provide evidence that among the lesions with varying disease burden at diagnosis, the FDG uptake is highest in cases with both axillary and distant metastasis, followed by those with axillary metastasis and then by those with no metastatic disease. These provide in vivo insight into tumor biology as FDG uptake is regarded as a surrogate marker of the same.

The effects of estrogen, progesterone, and C-erbB-2 receptor states on 18F-FDG uptake of primary breast cancer lesions.

UNLABELLED: The purpose of this prospective study was to investigate whether correlations exist between 18F-FDG uptake of primary breast cancer lesions and predictive and prognostic factors such as estrogen receptor (ER), progesterone receptor (PR), and C-erbB-2 receptor (C-erbB-2R) states. METHODS: Before undergoing partial or total mastectomy, 213 patients with newly diagnosed breast cancer underwent 18F-FDG PET (5.2 MBq/kg of body weight). The maximum standardized uptake value (SUV) of the primary lesion was measured in each patient. Standard immunohistochemistry was performed on a surgical specimen of the cancer lesion to characterize the receptor state of the tumor cells. Pearson chi2 tests were performed on the cross-tables of different receptor states to test any association that may exist among ER, PR, and C-erbB-2R. Maximum SUV measurements for different receptor states were compared using factorial ANOVA in a completely random design. RESULTS: After exclusion of certain lesions, 118 lesions were analyzed for this study. The mean maximum SUVs of ER-positive and ER-negative lesions were 3.03 +/- 0.26 and 5.64 +/- 0.75, whereas those of PR were 3.24 +/- 0.29 and 4.89 +/- 0.67, respectively, and those of C-erbB-2R were 4.64 +/- 0.70 and 3.70 +/- 0.35, respectively. Chi2 tests for ER and PR showed that if one is positive then the other tends to be positive as well (chi2 = 71.054, P < 0.01). For ER and C-erbB-2R states, if ER is positive, C-erbB-2R will more likely be negative (chi2 = 13.026, P < 0.01). No relationship was detected between PR and C-erbB-2R states (chi2 = 3.695, P > 0.05). ANOVAs showed that PR state alone (F = 0.095, P > 0.05) and C-erbB-2R state alone (F = 0.097, P > 0.05) had no effect on 18F-FDG uptake but ER state alone had an effect (F = 9.126, P < 0.01). ER and PR being together had no additional effect on 18F-FDG uptake. Our study also demonstrated that interactions exist between ER and C-erbB-2R state and between PR and C-erbB-2R state. CONCLUSION: SUV measurements may provide valuable information about the state of ER, PR, and C-erbB-2R and the associated glucose metabolism as measured by 18F-FDG uptake of the primary breast cancer lesions. Such an association may be of importance to treatment planning and outcome in these patients.

FDG PET in detecting primary and recurrent malignant salivary gland tumors.

PURPOSE: The aim of this study was to assess the role of PET in the management of patients with primary malignant salivary gland (SG) tumor. MATERIAL AND METHODS: Sixty-one FDG PET studies in 48 patients (median age 58, range 28-89 years, 20 female, 28 male) who were diagnosed with malignant SG tumors were retrospectively analyzed. Thirteen were referred for initial diagnosis and staging while there was a suspicion of recurrence and/or metastatic disease in 48 patients during the follow-up period. RESULTS: On PET examinations of 13 patients on initial presentation, 12 showed increased uptake in the primary lesion, while conventional methods (CT, MRI) were positive in 11 and were equivocal for 2 patients. Six patients with multiple nodal and 2 patients with distant metastases were detected by PET. Conventional methods demonstrated lymph node metastases in 5 of these patients. In the follow-up patient group, PET was inaccurate (false-negative or positive) in 4 (8%) patients with local recurrence, and in 4 (8%) with metastatic disease. However, 15 (31%) studies for recurrence and 7 (15%) for metastasis were false-negative with conventional radiologic methods. The sensitivity, specificity, and positive and negative predictive values for the detection of recurrent disease were 83%, 93%, 63%, and 98% for PET; 67%, 69%, 24%, and 94% for conventional methods, respectively. Overall sensitivity, specificity, positive and negative predictive values of PET for detecting metastatic disease were 93%, 96%, 82%, and 99%, while those of conventional methods were 80%, 95%, 75%, and 96%, respectively. CONCLUSION: These results demonstrate that FDG PET is not only superior to CT and/or MRI for staging at the initial presentation but also superior to conventional imaging methodologies for detecting local recurrence and regional lymph node and distant metastases in patients with malignant SG tumor.

Age-related structural and functional changes in the breast: multimodality correlation with digital mammography, computed tomography, magnetic resonance imaging, and positron emission tomography.

Preliminary results generated from digital mammography, computed tomography, magnetic resonance imaging, and (18)F-fluorodeoxyglucose positron emission tomography demonstrate concordant findings of decreasing glandular tissue and decreasing metabolic activity with increasing age. These results are presented in the context of a detailed literature review summarizing age-related changes in the breast, both from the histologic/physiologic and the imaging perspectives. We also discuss potential applications of this approach and emphasize the importance of new advanced imaging technologies to offer high levels of quantitative precision for tissue characterization for research and clinical purposes.

Structural and functional imaging of normal bone marrow and evaluation of its age-related changes.

A number of noninvasive imaging techniques have been used for the evaluation of bone marrow, including magnetic resonance imaging (MRI) and bone marrow scintigraphy. The appearance of bone marrow on MRI varies considerably depending on the proportion of red and yellow marrow, and the composition of the red marrow and its distribution with relation to age and sex. The composition of bone marrow also can vary under physiological and pathological conditions. MRI is a highly sensitive technique for evaluating the bone marrow, but it is limited in its practical use for whole-body bone marrow screening. Bone marrow scintigraphy with radiolabeled compounds such as technetium-99m-labeled nanocolloid and monoclonal antibodies has the advantage of evaluating the entire bone marrow, and has been used for the diagnosis of various bone marrow disorders. In addition, (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging can be used to evaluate bone marrow metabolism and disease and to provide information about the state of the primary tumor, lymph nodes, and distant metastases. Understanding of the appearance of normal bone marrow, including age- and sex-specific differences with each of these imaging modalities, is essential to permit accurate diagnosis of benign and malignant bone marrow disorders. We present a review of MRI and scintigraphy of normal bone marrow with some emphasis on FDG-PET imaging in assessing marrow activity in normal and abnormal states and also present preliminary data regarding normal age-related changes in bone marrow through use of FDG-PET, as well as the role of segmentation of bone marrow on MRI for quantitative calculation of the metabolic volumetric product for red marrow metabolism using FDG-PET.

Iodine-123 as a diagnostic imaging agent in differentiated thyroid carcinoma: a comparison with iodine-131 post-treatment scanning and serum thyroglobulin measurement.

PURPOSE: Using 123I for diagnostic purposes avoids the risk of stunning for subsequent radioiodine treatment and affords an excellent image quality. In this study we assessed the role of 123I in comparison with 131I post-treatment imaging in patients with thyroid cancer. METHODS: We compared a total of 292 123I scans with their corresponding post-treatment 131I images. Patients received a therapeutic dose of 131I following diagnostic scanning with 50-111 MBq of 123I. All patients were in a hypothyroid state (>30 microIU/l) before radioiodine administration for either diagnostic or therapeutic purposes. RESULTS: In 228 out of 263 patients with a positive diagnostic scan, 123I whole-body scan findings were concordant with those of corresponding post-treatment 131I images (concordance rate 87%). However, there were 44 additional foci of abnormal uptake on post-treatment 131I scans in 22 discordant cases with no impact on therapeutic management of the patients. In 13 patients, there was at least one new site on post-treatment images that had been missed on pretreatment 123I images. Twenty-nine patients with a negative diagnostic scan were treated with 131I owing to a high serum thyroglobulin level (range 11.3-480 ng/ml). Radioiodine uptake sites were seen in eight post-treatment scans. In 21 pairs of whole-body scans, both the pre- and the post-treatment scan were negative (concordance rate 72.4%). CONCLUSION: 123I scanning is comparable to high-dose 131I post-treatment imaging in thyroid carcinoma patients, and 123I offers excellent image quality as a diagnostic agent. It avoids disadvantages such as stunning before treatment and delivery of a high radiation dose to patients.

Positron Emission Tomography and Thyroid Cancer.

Follicular cell-derived differentiated thyroid carcinoma has a fairly good prognosis; however, the probability of recurrence is high, which increases the morbidity and mortality rates significantly. The most common agent used in patients with differentiated carcinoma for both diagnostic and therapeutic purposes is radioiodine; however, it has been reported that thyroid tumor cells lose the ability to take up iodine because of de-differentiation. Positron emission tomography (PET) using 18-F-fluorodeoxyglucose (FDG) has proven useful in patients with differentiated thyroid carcinoma presenting serologic evidence of persistent disease but negative whole-body radioiodine scanning. There is an on-going debate on the role of PET in revealing the malignancy in thyroid nodules preoperatively. As a functional imaging modality, FDG-PET imaging may have some limitations because of its finite spatial resolution, especially in patients with minimal cervical adenopathy or small pulmonary metastasis; however its accuracy may improve using fusion imaging with either computed tomography (PET-CT) or magnetic resonance imaging (PET-MR imaging).

Dual time point 18F-FDG PET imaging detects breast cancer with high sensitivity and correlates well with histologic subtypes.

UNLABELLED: This prospective study was designed to assess the utility of the dual time point imaging technique by (18)F-FDG PET in detecting primary breast cancer and to determine whether there is a relationship between (18)F-FDG uptake and its change over time and the histopathologic subtypes. METHODS: One hundred fifty-two patients with newly diagnosed breast cancer underwent 2 sequential PET scans (dual time point imaging) for preoperative staging. The maximum standardized uptake value (SUVmax) of (18)F-FDG was measured from both time points. The percent change in SUVmax (Delta%SUVmax) between time points 1 (SUVmax1) and 2 (SUVmax2) was calculated. Patients were divided into 2 groups according to histopathology as invasive and noninvasive. Invasive tumors were also divided into 2 groups (>10 mm and 4-10 mm). The tumor-to-contralateral normal breast (background) ratios of SUVmax at both time points for groups were measured and the Delta%SUVmax values were calculated. RESULTS: The mean +/- SD of the SUVmax1, the SUVmax2, and the Delta%SUVmax were 3.9 +/- 3.7, 4.3 +/- 4.0, and 8.3% +/- 11.5% for invasive; 2.0 +/- 0.6, 2.1 +/- 0.6, and 3.4% +/- 13.0% for noninvasive; and were 1.2 +/- 0.3, 1.1 +/- 0.2, and -10.0% +/- 10.8% for the contralateral normal breast groups, respectively. In the comparison of SUVmax1, Delta%SUVmax, and the tumor-to-background ratios among groups, all results were significant (P < 0.001). Visual assessment revealed that the sensitivity of dual time point imaging was 90.1% for invasive cancer >10 mm, 82.7% for invasive breast cancers 4-10 mm, and 76.9% for noninvasive breast cancers. CONCLUSION: Dual time point imaging is a simple and noninvasive method that may improve the sensitivity and accuracy of (18)F-FDG PET in assessing patients with primary breast cancer. The changes that are noted in SUVs in dual time point imaging vary depending on the histopathologic type of primary breast cancer.