Evolving role of positron emission tomography in breast cancer imaging

Widefield ultra-high-density optical breast tomography system supplementing x-ray mammography

We report a wide-field compressive diffuse optical tomography (DOT) system - optical mammography co-imager (OMCI) - which aims to augment tens of thousands of existing x-ray mammography or tomosynthesis systems worldwide by adding functional assessment of breast tissue and improve cancer diagnosis. The OMCI system utilizes large field-of-view structured light illumination and single-pixel-camera based detection techniques to produce ultra-high spatial sampling density while ensuring that the inverse problem remains compact via the development of a unique target-adaptive pattern optimization technique to achieve compressive-sensing based measurements. The reconstructed images can be further enhanced by applying a compositional-prior-guided DOT reconstruction algorithm with tissue structural priors derived from a separately acquired x-ray mammography scans. In this report, we describe the design details and performance characterization of the imaging hardware as well as DOT image reconstruction pipelines. To validate this multi-modal breast DOT system, we include reconstruction results from both tissue-mimicking optical phantoms as well as clinical measurements from normal breasts obtained from a clinical study. Sample reconstructions from a breast containing a malignant tumor are also included, showing the potential of localizing and characterizing breast lesions using multi-modal measurements combining x-ray and DOT.

Prognosis Associated with Glycolytic Activity in Regional Lymph Nodes of Patients with Previously Untreated Metastatic Breast Cancer: A Preliminary Study

Better mechanisms of predicting prognoses in patients with metastatic breast cancer will improve the identification of patients for whom curative treatments may be the most effective. In this study, the prognostic value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) was assessed in patients with metastatic breast cancer. A retrospective analysis of women who underwent 18F-FDG PET/CT for staging of newly diagnosed metastatic breast cancer was conducted. In each patient, the maximum standardized uptake value (SUV) and total lesion glycolysis (TLG) of primary tumors and regional lymph nodes were measured and analyzed for association with survival using the Cox proportional hazards regression model. From 346 consecutive patients, 32 with metastatic invasive ductal carcinoma of the breast were included in the study. The median duration of follow-up was 22.5 months. Disease progression occurred in 26 patients, and 11 patients died. When multivariate analyses with a stepwise forward regression were applied, only the maximum SUV and TLG of regional lymph nodes showed a significant correlation with progression-free survival and overall survival, respectively. This study demonstrates that increased 18F-FDG uptake in regional lymph nodes is a strong independent predictor of survival in women with metastatic invasive ductal carcinoma of the breast.

The Impact of the Amendment of the Health Insurance Coverage for F-18 Fluorodeoxyglucose Positron Emission Tomography on the Healthcare Behaviors for Breast Cancer: An Interrupted Time Series Analysis of the Korean National Data From 2013 to 2018

BACKGROUND

F-18 Fluorodeoxyglucose positron emission tomography (F-18 FDG PET), which can cover the body from the skull base to the thigh in one scan, is beneficial for evaluating distant metastasis. F-18 FDG PET has interested policymakers because of its relatively high cost. This study investigated the effect of the F-18 FDG PET reimbursement criteria amendment on healthcare behavior in breast cancer using an interrupted time series (ITS) analysis.

METHODS

We retrospectively analyzed the inpatient and outpatient data from Korea's Health Insurance Review and Assessment Service (HIRA) from January 1, 2013 to December 31, 2018. ITS analysis was performed for the number of each medical imaging modality and the total medical imaging cost of the breast cancer patients.

RESULTS

The annual number of breast cancer patients has been increasing steadily since 2013. The trend of F-18 FDG PET increased before the reimbursement criteria was amended, but intensely decreased immediately thereafter. The chest and abdomen computed tomography scans showed a statistically significant increase immediately after the amendment and kept steadily increasing. A change in the total medical imaging cost for the breast cancer patient claimed every month showed an increasing trend before the amendment (β = 5,475, standard error [SE] = 1,992, P = 0.008) and rapid change immediately after (β = -103,317, SE = 16,152, P < 0.001). However, there was no significant change in the total medical imaging cost at the long-term follow-up (β = -912, SE = 1,981, P = 0.647).

CONCLUSION

Restriction of health insurance coverage for cancer may affect healthcare behaviors. To compensate for it, the policymakers must consider this and anticipate the impact following implementation.

Clinical-Diagnostic Relevance of Breast "Incidentaloma" Detected During 18F-Fluoro-2-Deoxy-D-Glucose Positron Emission Tomography/Computed Tomography: Correlation with Radiological Imaging and Histopathology

Aim:

This study aims to study the clinical-diagnostic relevance of incidental breast uptake (“incidentaloma”) on 18F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) scan performed for other indications and to correlate it with radiological imaging and histopathology.

Materials and Methods:

We retrospectively evaluated 3675 FDG-PET scans, identifying 43 patients with breast “incidentaloma.” Thirty of these findings were further investigated with clinical examination, mammography (MMX), UltraSound (US) and/or magnetic resonance (MR). Cases suspected for malignancy underwent US-guided macro-biopsy (USMB) or MR-guided biopsy. Correlations between FDG-PET, radiology findings, age, and histopathology were evaluated.

Results:

patients who performed both US and MMX were 19. Ten consequently underwent USMB, one MR-guided biopsy, the remaining 8 were not further investigated. Nine patients had a diagnosis of malignancy. Among 11 patients who performed only US and consequently, USMB 6 had a diagnosis of malignancy. Histopathology of the 22 patients with both morphological and glucometabolic alterations showed different types of benign or malignant neoplasia, with a cumulative 68.2% incidence of malignancy. Seven lesions showed a SUV_max >2.5, while the remaining 15 a SUV_max <2.5. There was no statistically significant correlation between SUV_max and histology, therefore SUV_max parameter should not be used to discriminate between benign and malignant findings. No significant correlation between patient age and tumor characterization was found.

Conclusions:

incidental mammary uptake during an FDG-PET scan may represent a clue suggesting to investigate PET findings. In this subset of patients, early diagnosis may lead to a change in clinical management with a favorable impact on prognosis and a significant reduction in healthcare costs.

Progress and Future Trends in PET/CT and PET/MRI Molecular Imaging Approaches for Breast Cancer

Breast cancer is a major disease with high morbidity and mortality in women worldwide. Increased use of imaging biomarkers has been shown to add more information with clinical utility in the detection and evaluation of breast cancer. To date, numerous studies related to PET-based imaging in breast cancer have been published. Here, we review available studies on the clinical utility of different PET-based molecular imaging methods in breast cancer diagnosis, staging, distant-metastasis detection, therapeutic and prognostic prediction, and evaluation of therapeutic responses. For primary breast cancer, PET/MRI performed similarly to MRI but better than PET/CT. PET/CT and PET/MRI both have higher sensitivity than MRI in the detection of axillary and extra-axillary nodal metastases. For distant metastases, PET/CT has better performance in the detection of lung metastasis, while PET/MRI performs better in the liver and bone. Additionally, PET/CT is superior in terms of monitoring local recurrence. The progress in novel radiotracers and PET radiomics presents opportunities to reclassify tumors by combining their fine anatomical features with molecular characteristics and develop a beneficial pathway from bench to bedside to predict the treatment response and prognosis of breast cancer. However, further investigation is still needed before application of these modalities in clinical practice. In conclusion, PET-based imaging is not suitable for early-stage breast cancer, but it adds value in identifying regional nodal disease and distant metastases as an adjuvant to standard diagnostic imaging. Recent advances in imaging techniques would further widen the comprehensive and convergent applications of PET approaches in the clinical management of breast cancer.

Comparison of Natural Course between Thyroid Cancer Nodules and Thyroid Benign Nodules

BACKGROUND

The natural course of thyroid cancer nodules and benign nodules is different. This study was to compare the changes in size between thyroid cancer nodules and thyroid benign nodules. The risk factors associated with the changes of thyroid cancer nodules were assessed.

METHODS

This study contains retrospective observational and prospective analysis. A total of 113 patients with 120 nodules were recruited in the cancer group, and 116 patients with 119 nodules were enrolled in the benign group. Thyroid ultrasonography was performed at least two times at more than 1-year interval.

RESULTS

The mean follow-up durations were 29.5±18.8 months (cancer group) and 31.9±15.8 months (benign group) (P=0.32). The maximum diameter change in length was 0.36±0.97 mm/year in the cancer group and -0.04±0.77 mm/year in the benign group (P<0.01). The volume was significantly increased in the cancer group compared with the benign group (0.06±0.18 mL/year vs. 0.004±0.05 mL/year, respectively, P<0.01; 26.9%±57.9%/year vs. 1.7%±26.0%/year, P<0.01). Initial maximum diameter (β=0.02, P<0.01) and initial volume (β=0.13, P<0.01) were significantly associated with volume change (mL)/year. Initial maximum standardized uptake value did not predict the nodule growth.

CONCLUSION

It is suggested that thyroid cancer nodules progress rapidly compared with benign nodules. Initial size and volume of nodule were independent risk factors for cancer nodule growth.

Tumor characteristics and metabolic quantification in carcinoma breast: An institutional experience

BACKGROUND

In India, carcinoma breast is the most common cancer among urban women population and second most common cancer after carcinoma cervix in rural areas. One in 22 women in India develops carcinoma of the breast in their lifetime. Fluorine-18-fluoro-2-deoxy-D-glucose (18F-FDG) uptake in breast cancer usually indicates the degree of tumor metabolism and hence can predict its behavior and prognosis. On the other hand, the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER-2) or neu state of breast cancer is a biomarker that provides important prognostic information in addition to predicting response to therapy.

AIMS

The main objective of this study is to assess whether a correlation exists between 18F-FDG uptake in untreated cases of breast cancer, their receptor status (ER, PR, and HER-2 or neu), tumor histology, and tumor size.

SUBJECTS AND METHODS

Sixty consecutive female patients, with biopsy-proven primary breast cancer, were enrolled in this prospective study for whom 18F-FDG positron emission tomography-computed tomography scan was done in the Department of Nuclear Medicine. Results obtained were analyzed using appropriate statistical tests (t-test and Pearson Chi-square tests), and interpretation was made with 95% confidence level.

RESULTS

In our series, a positive correlation between tumor size, high tumor grade, and standardized uptake value (SUV) was found. Tumors with positive receptor status for estrogen, progesterone, and HER-2/neu receptors had statistically insignificant lower maximum SUV (SUVmax) values than their negative counterparts. Triple-negative breast tumors (ER-, PR-, and no overexpression of HER-2/neu) are currently a subject of major interest because of their aggressiveness, poor prognosis, and lack of targeted therapy. Based on receptor status when the SUVmaxof the group with triple-negative receptor status (ER-/PR-/HER-2/neu-) was compared to rest of the patient group, it was seen that patients with negative receptor status had significantly higher mean SUVmaxvalues.

CONCLUSIONS

We have inferred that in patients with breast cancer, various biological parameters such as tumor size, grade, histology, and hormonal receptor status have different impact on tumor metabolic activity.

Automatic segmentation of lesion from breast DCE-MR image using artificial fish swarm optimization algorithm

Interpreting Dynamic Contrast-Enhanced (DCE) MR images for signs of breast cancer is time consuming and complex, since the amount of data that needs to be examined by a radiologist in breast DCE-MRI to locate suspicious lesions is huge. Misclassifications can arise from either overlooking a suspicious region or from incorrectly interpreting a suspicious region. The segmentation of breast DCE-MRI for suspicious lesions in detection is thus attractive, because it drastically decreases the amount of data that needs to be examined. The new segmentation method for detection of suspicious lesions in DCE-MRI of the breast tissues is based on artificial fishes swarm clustering algorithm is presented in this paper. Artificial fish swarm optimization algorithm is a swarm intelligence algorithm, which performs a search based on population and neighborhood search combined with random search. The major criteria for segmentation are based on the image voxel values and the parameters of an empirical parametric model of segmentation algorithms. The experimental results show considerable impact on the performance of the segmentation algorithm, which can assist the physician with the task of locating suspicious regions at minimal time.

Prognostic Value of Percentage Change in Metabolic Parameters as Measured by Dual-Time Point 18F-FDG PET/CT in Premenopausal Women with Invasive Ductal Breast Carcinoma

OBJECTIVES

We retrospectively evaluated the prognostic significance of dual-time point (DTP) ¹⁸F-FDG positron emission tomography/computed tomography (PET/CT) parameters compared with clinicopathological findings in premenopausal women with invasive ductal breast carcinoma (IDC).

MATERIALS AND METHODS

Sixty-six premenopausal women (mean age: 42.7 ± 5.6, range: 29.5-51.8 years) who had pathologically confirmed IDC were enrolled. The maximum standardized uptake value (SUV_max), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were measured and used to calculate percentage changes over the DTP time interval. We analyzed the prognostic significance of DTP PET/CT parameters, clinicopathological factors of pathologic tumor diameter (pTD), axillary lymph node status (ANS), nuclear grade, histologic grade, and immunohistochemistry findings using univariate and multivariate analyses.

RESULTS

Disease recurrence was observed in 22 patients. In univariate analysis, SUV_max > 7.39, MTV > 4.28, TLG > 52.38, %ΔSUV_max > 20.44, %ΔTLG > -13.86, pTD > 2.8 cm, positive ANS, estrogen receptor (ER) negativity, and triple negativity were associated with worse prognosis than those of opposite groups in recurrence-free survival (all p < 0.05). %ΔSUV_max (>20.44, p = 0.0042), TLG (>52.38, p = 0.0002), and ER negativity (p = 0.0003) were independent prognostic variables after multivariate analysis.

CONCLUSION

Percentage changes in SUV_max using DTP PET/CT and TLG were significant independent prognostic factors of disease recurrence along with ER negativity in premenopausal women with IDC.

Potential Clinical Applications of 18F-Fluorodeoxyglucose Positron Emission Tomography/Magnetic Resonance Mammography in Breast Cancer

The whole-body positron emission tomography (PET)/magnetic resonance (MR) scan is a cutting edge technology providing comprehensive structural information from MR imaging and functional features from PET in a single session. Recent research findings and clinical experience have shown that ¹⁸F-fluorodeoxyglucose (FDG) whole-body PET/MR imaging has a diagnostic performance comparable with or superior to that of PET/CT in the field of oncology, including for breast cancer. In particular, FDG PET/MR mammography in the prone position with the breast hanging in a pendant manner can provide more comprehensive information about the metabolism, anatomy, and functional features of a breast lesion than a whole-body PET/MR scan. This article reports on current state-of-the-art PET/MR mammography in patients with breast cancer and the prospects for potential application in the future.

Clinical Utility of (18)F-FDG PET/CT in brachial plexopathy secondary to metastatic breast cancer

Role of fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) in breast cancer is rapidly evolving. Brachial plexopathy is a rare clinical entity in follow-up of operated breast cancer patients, who presents with disease recurrence in the axilla. Conventionally, magnetic resonance imaging is the imaging modality of choice for diagnostic evaluation in these cases and only few case reports/short studies have explored the utility of PET/CT in this clinical indication. We present here a short case series to demonstrate the utility of PET/CT as an important adjunctive imaging modality to magnetic resonance to supplement diagnosis of brachial plexopathy, differentiate radiation-induced brachial plexopathy from neoplastic plexopathy, accurately restage the disease and to monitor response to chemotherapy.

PET/MR in Breast Cancer

Breast cancer is an international public health concern in which an optimal treatment plan requires a precise staging. Both MRI and PET imaging techniques have made significant progress in the last decades with constant improvements that made both modalities clinically relevant in several stages of breast cancer management and follow-up. On one hand, specific breast MRI permits high diagnostic accuracy for local tumor staging, and whole-body MRI can also be of great use in distant staging, eventually accompanied by organ-specific MRI sequences. Moreover, many different MRI sequences can be performed, including functional MRI, letting us foresee important improvements in breast cancer characterization in the future. On the contrary, (18)F-FDG-PET has a high diagnostic performance for the detection of distant metastases, and several other tracers currently under development may profoundly affect breast cancer management in the future with better determination of different types of breast cancers allowing personalized treatments. As a consequence PET/MR is a promising emerging technology, and it is foreseeable that in cases where both PET and MRI data are needed, a hybrid acquisition is justified when available. However, at this stage of deployment of such hybrid scanners in a clinical setting, more data are needed to demonstrate their added value beyond just patient comfort of having to undergo a single examination instead of two, and the higher confidence of diagnostic interpretation of these co-registered images. Optimized imaging protocols are still being developed and are prone to provide more efficient hybrid protocols with a potential improvement in diagnostic accuracy. More convincing studies with larger number of patients as well as cost-effectiveness studies are needed. This article provides insights into the current state-of-the-art of PET/MR in patients with breast cancer and gives an outlook on future developments of both imaging techniques and potential applications in the future.

Ability of contrast-enhanced ultrasonography to determine clinical responses of breast cancer to neoadjuvant chemotherapy

OBJECTIVE

We aimed to determine whether contrast-enhanced ultrasonography can predict the effects of neoadjuvant chemotherapy on breast cancer.

METHODS

The clinical responses of 63 consecutive patients with breast cancer (T1-4, N0-1, M0) to neoadjuvant chemotherapy between October 2012 and May 2015 were assessed using contrast-enhanced magnetic resonance imaging, positron emission tomography/computed tomography and contrast-enhanced ultrasonography. Perfusion parameters for contrast-enhanced ultrasonography were created from time-intensity curves based on enhancement intensity and temporal changes to objectively evaluate contrast-enhanced ultrasonography findings. The sensitivity, specificity and accuracy of contrast-enhanced ultrasonography, magnetic resonance imaging and positron emission tomography/computed tomography to predict a pathological complete response were compared after confirming the pathological findings of surgical specimens.

RESULTS

Twenty-three (36.5%) of the 63 patients achieved pathological complete response. The sensitivity, specificity and accuracy of contrast-enhanced ultrasonography for predicting pathological complete response were 95.7% (82.5-99.2%), 77.5% (69.9-79.5%) and 84.1% (74.5-86.7%). The sensitivity of contrast-enhanced ultrasonography was significantly greater than that of magnetic resonance imaging (95.7 vs. 69.6%, P = 0.047). The specificity and accuracy were significantly greater and tended to be greater, respectively, for contrast-enhanced ultrasonography than positron emission tomography/computed tomography (specificity, 77.5 vs. 52.5%, P = 0.02; accuracy, 84.1 vs. 69.8%, P = 0.057).

CONCLUSIONS

Contrast-enhanced ultrasonography might serve as a new diagnostic modality when planning therapeutic strategies for patients with breast cancer after neoadjuvant chemotherapy.

A preliminary report of breast cancer screening by positron emission mammography

OBJECTIVE

Fluorine-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET) and PET/computed tomography (PET/CT) have had a considerable impact on the detection of various malignancies. PET and PET/CT are minimally invasive methods that can provide whole-body imaging at one time. Therefore, an FDG-PET cancer screening program has been widely used in Japan. However, the breast cancer detection rate of FDG-PET cancer screening is relatively low. Therefore, FDG-PET screening is not recommended for breast cancer screening. Positron emission mammography (PEM) is a high-resolution molecular breast imaging technology. PEM can detect small breast cancers that cannot be detected on PET or PET/CT images due to limited spatial resolution. We have performed opportunistic breast cancer screening using PEM since 2011. To the best of our knowledge, this is the first report regarding PEM breast cancer screening.

METHODS

This study enrolled 265 women. PEM images were analyzed by agreement of 2 experienced nuclear medicine physicians. The readers were given information from medical interview sheet. US findings were interpreted holistically. The number of participants, patient recall rate, further examination rate, and cancer detection rate by year were calculated.

RESULTS

The overall recall rate was 8.3%; the work-up examination rate was 77.3%, and cancer detection rate was 2.3%. The positive predictive value of PEM was 27.3%. Six cancers were found by PEM screening. Five were invasive cancers and one was ductal carcinoma in situ. Histological tumor sizes were reported in three cases: 0.7, 1.2, and 2 cm.

CONCLUSION

PEM screening appears to have potential for breast cancer screening.

Diagnostic accuracy of (18)F-FDG PET/CT compared with that of contrast-enhanced MRI of the breast at 3 T

PURPOSE

To compare the diagnostic accuracy of prone (18)F-FDG PET/CT with that of contrast-enhanced MRI (CE-MRI) at 3 T in suspicious breast lesions. To evaluate the influence of tumour size on diagnostic accuracy and the use of maximum standardized uptake value (SUVMAX) thresholds to differentiate malignant from benign breast lesions.

METHODS

A total of 172 consecutive patients with an imaging abnormality were included in this IRB-approved prospective study. All patients underwent (18)F-FDG PET/CT and CE-MRI of the breast at 3 T in the prone position. Two reader teams independently evaluated the likelihood of malignancy as determined by (18)F-FDG PET/CT and CE-MRI independently. (18)F-FDG PET/CT data were qualitatively evaluated by visual interpretation. Quantitative assessment was performed by calculation of SUVMAX. Sensitivity, specificity, diagnostic accuracy, area under the curve and interreader agreement were calculated for all lesions and for lesions <10 mm. Histopathology was used as the standard of reference.

RESULTS

There were 132 malignant and 40 benign lesions; 23 lesions (13.4%) were <10 mm. Both (18)F-FDG PET/CT and CE-MRI achieved an overall diagnostic accuracy of 93%. There were no significant differences in sensitivity (p = 0.125), specificity (p = 0.344) or diagnostic accuracy (p = 1). For lesions <10 mm, diagnostic accuracy deteriorated to 91% with both (18)F-FDG PET/CT and CE-MRI. Although no significant difference was found for lesions <10 mm, CE-MRI at 3 T seemed to be more sensitive but less specific than (18)F-FDG PET/CT. Interreader agreement was excellent (κ = 0.85 and κ = 0.92). SUVMAX threshold was not helpful in differentiating benign from malignant lesions.

CONCLUSION

(18)F-FDG PET/CT and CE-MRI at 3 T showed equal diagnostic accuracies in breast cancer diagnosis. For lesions <10 mm, diagnostic accuracy deteriorated, but was equal for (18)F-FDG PET/CT and CE-MRI at 3 T. For lesions <10 mm, CE-MRI at 3 T seemed to be more sensitive but less specific than (18)F-FDG PET/CT. Quantitative assessment using an SUVMAX threshold for differentiating benign from malignant lesions was not helpful in breast cancer diagnosis.

Feasibility of FDG-PET/CT for the initial diagnosis of papillary thyroid cancer

To assess the role of [18F]-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) as a preoperative diagnostic tool in papillary thyroid carcinoma (PTC). From 2011 to 2014, 197 patients with PTC (246 tumor foci in all) underwent FDG-PET. Among these patients, 46 underwent neck dissection for lateral neck metastasis. According to the FDG avidity of the tumor foci or lateral neck metastasis, factors associated with the prognostic value were evaluated by univariate and multivariate logistic regression analyses. Among the 197 patients, 7 (3.6 %) were incidentally found to have non-thyroid origin malignancy. Additionally, 63.0 % (155/246) of PTC foci showed FDG uptake on PET/CT. Univariate analysis showed that the tumor size, the presence of extrathyroidal extension, BRAF mutation, and Hashimoto thyroiditis were associated with FDG avidity. However, except for pathological extrathyroidal extension, the other factors showed statistically significant correlations with FDG avidity (p < 0.001, p = 0.008, and p = 0.009, respectively). FDG uptake in lateral neck node metastasis showed high specificity and negative predictive value (NPV). In four cases of nonspecific findings on ultrasonography (USG)/CT, FDG avidity was helpful to diagnose the presence of lateral neck metastasis. The maximum standardized uptake value (SUVmax) of PET/CT was correlated with the maximum diameter of the involved lateral node. FDG avidity did not show any significance in the recurrence-free survival of both the thyroid tumor and lateral neck metastasis. The FDG avidity of PTC did not show prognostic predictive meaning. However, in the case of lateral neck metastasis, FDG avidity showed high sensitivity and NPV, and could provide better information in cases of nonspecific findings on USG and CT.

VALIDATION OF THERAPEUTIC RESPONSE ASSESSMENT BY BONE SCINTIGRAPHY IN PATIENTS WITH BONE-ONLY METASTATIC BREAST CANCERS DURING ZOLEDRONIC ACID TREATMENT: COMPARISON WITH COMPUTED TOMOGRAPHY ASSESSMENT

PURPOSE

To validate the use of bone scintigraphy (BS) versus computed tomography (CT) for therapeutic monitoring in patients during treatment with zoledronic acid.

MATERIALS AND METHODS

Eleven patients with bone-only metastatic disease and being treated with zoledronic acid were included. The effects of therapies including chemotherapy and hormone therapy were evaluated in 25 separate examinations in total as follows: complete response (CR), when no bone metastasis was visible; partial response (PR), when a decrease in the lesion area was detected; stable disease (SD), when no or slight change was observed; and progressive disease (PD), when new or enlarged lesion areas were observed.

RESULTS

The accuracies of examination by Readers 1, 2, and 3 respectively were 76%, 80% and 76% for BS, 52%, 48%, and 40% for CT, and 64%, 52% and 60% for BS and CT combined with Readers 2 and 3 observing significant differences between CT and BS results. The rates of interobserver agreement between Readers 1 and 2, between Readers 1 and 3, and between Reader 2 and 3 respectively, were 84%, 80% and 88% (κ = 0.648, 0.561 and 0.766) for BS, 52%, 56%, and 60% (κ = 0.180, 0.278 and 0.282) for CT, and 52%, 60%, and 56% (κ = 0.215, 0.282 and 0.232) for CT and BS combined.

CONCLUSION

BS is effective for assessing the response of bone metastasis to therapy in patients during zoledronic acid treatment.

Clinical value of visually identifiable 18F-fluorodeoxyglucose uptake in primary papillary thyroid microcarcinoma

OBJECTIVE

This study evaluates the relationship between visually identifiable (18)F-fluorodeoxyglucose (FDG) uptake in primary papillary thyroid microcarcinoma (PTMC) and tumor aggressiveness.

STUDY DESIGN

Historical cohort study.

SETTING

Tertiary care center.

METHODS

Clinicopathological factors and PET/CT findings of 219 PTMC surgical patients who underwent preoperative (18)F-FDG positron emission tomography/computed tomography (PET/CT) were retrospectively reviewed.

RESULTS

(18)F-FDG uptake was observed in the tumors of 124 (56.6%) patients. Tumor size (odds ratio [OR] = 1.774; 95% confidence interval [CI], 1.416-2.223; P < .0001) and Hashimoto thyroiditis (OR = 2.815; CI, 1.237-6.404; P = .014) independently predicted (18)F-FDG uptake. Tumor size (OR = 1.495; CI, 1.217-1.835; P < .0001) and BRAF(V600E) mutation (OR = 3.320; CI, 1.056-10.432; P = .040) independently predicted extrathyroidal invasion. Multiplicity (OR = 2.375; CI, 1.278-4.415; P = .006) independently predicted central lymph node metastasis.

CONCLUSION

(18)F-FDG uptake in PTMC depends on tumor size and Hashimoto thyroiditis. Therefore, preoperative PET/CT for PTMC may not help in evaluating tumor aggressiveness.

Benign breast lesions detected by positron emission tomography-computed tomography

(18)F-fluorodeoxyglucose positron emission computed tomography (FDG PET-CT) is widely used in the initial staging and response evaluation of patients with malignancy. This review describes a spectrum of benign breast findings incidentally detected by FDG PET-CT at staging that may be misinterpreted as malignancy. We describe the pattern of distribution and intensity of FDG uptake in a spectrum of benign breast diseases with their corresponding typical morphological imaging characteristics to help the nuclear medicine physician and/or general radiologist identify benign lesions, avoiding unnecessary breast imaging work-up and biopsies.

Clinical significance of FDG-PET/CT at the postoperative surveillance in the breast cancer patients

AIM

We evaluated the clinical role of [(18)F]-2-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG-PET/CT) compared with conventional imaging (CI) to detect locoregional recurrence or distant metastasis during postoperative surveillance of patients with breast cancer.

MATERIALS AND METHODS

We included 1,819 examinations of 1,161 patients, who underwent FDG-PET/CT and CI, including mammography, breast ultrasound, whole-body bone scintigraphy, and chest radiography for postoperative surveillance. All patients had a history of surgery with or without adjuvant treatment due to more than stage II breast cancer between November 2003 and November 2009. We evaluated the diagnostic performance of CI, FDG-PET/CT, and combined CI and FDG-PET/CT for detecting locoregional recurrence, distant metastasis, and incidental cancer. We also analyzed false-positive and false-negative results in both FDG-PET/CT and CI.

RESULTS

Sensitivity, specificity, positive predictive value, and negative predictive value of CI were 75.4, 98.7, 93.4, and 94.3 %. Those of FDG-PET/CT were 97.5, 98.8, 95.4, and 99.4 %. Those of the combined results were 98.6, 98.2, 96.7, and 99.7 %. Sensitivity of FDG-PET/CT was significantly higher than that of CI (P < 0.05). Sensitivity of combined CI and FDG-PET/CT results improved, but they were not significantly different from those of FDG-PET/CT alone (P = 0.43). Seventeen false-positive and nine false-negative cases were detected with FDG-PET/CT, and 19 false-positive and 88 false-negative cases were detected with CI.

CONCLUSION

FDG-PET/CT is considered as an acceptable diagnostic imaging modality for postoperative surveillance of patients with breast cancer.

Radionuclide methods for breast cancer staging

Staging at initial presentation is one of the important prognostic factors for patients with breast cancer. Depending on the extent of disease spread, staging is divided into locoregional and distant or systemic. Locoregional staging includes axillary and internal mammary lymph node evaluation and distant or systemic staging includes evaluation of sites beyond the lymph node. Fluorodeoxyglucose-positron emission tomography (FDG-PET) is not sensitive to detect small metastasis in axillary lymph node. The current standard of axillary lymph node staging in early-stage breast cancer is therefore sentinel lymph node biopsy. Internal mammary lymph nodes are not commonly included in routine staging. In advanced-stage breast cancer, FDG-PET and PET/computed tomography (CT) are the modalities of choice to evaluate locoregional and distant metastasis. FDG-PET and PET/CT often detect occult metastasis, which is not visible on any other modalities including diagnostic CT scan. Detection of occult metastasis may potentially change in treatment options. This is particularly important in locally advanced breast cancer, which tends to develop early distant metastasis.

Positron emission tomography: clinical applications in oncology. Part 1

Positron emission tomography is a functional diagnostic imaging technique, which can accurately measure in vivo distribution of a radiopharmaceutical with high resolution. The ability of positron emission tomography to study various biologic processes opens up new possibilities for both research and day-to-day clinical use. Positron emission tomography has progressed rapidly from being a research technique in laboratories to a routine clinical imaging modality becoming part of armamentarium for the medical profession. The most widely used radiotracer in positron emission tomography is 18F-fluoro-2-deoxy-D-glucose (FDG), which is an analog of glucose. FDG uptake in cells is directly proportional to glucose metabolism of cells. Since glucose metabolism is increased many fold in malignant tumors, positron emission tomography has a high sensitivity and high negative predictive value. Positron emission tomography with FDG is now the standard of care in initial staging, monitoring the response to therapy and management of lung cancer, colorectal cancer, lymphoma, melanoma, esophageal cancer, head and neck cancer and breast cancer. The aim of this article is to review the clinical applications of positron emission tomography in oncology.

Quantitative receptor-based imaging of tumor proliferation with the sigma-2 ligand [(18)F]ISO-1

The sigma-2 receptor is expressed in higher density in proliferating (P) tumor cells versus quiescent (Q) tumor cells, thus providing an attractive target for imaging the proliferative status (i.e., P:Q ratio) of solid tumors. Here we evaluate the utility of the sigma-2 receptor ligand 2-(2-[(18)F]fluoroethoxy)-N-(4-(3,4-dihydro-6,7-dimethoxyisoquinolin-2(1H)-yl)butyl)-5-methyl-benzamide, [(18)F]ISO-1, in two different rodent models of breast cancer. In the first study, small animal Positron Emission Tomography (PET) imaging studies were conducted with [(18)F]ISO-1 and (18)FDG in xenografts of mouse mammary tumor 66 and tracer uptake was correlated with the in vivo P:Q ratio determined by flow cytometric measures of BrdU-labeled tumor cells. The second model utilized a chemically-induced (N-methyl-N-nitrosourea [MNU]) model of rat mammary carcinoma to correlate measures of [(18)F]ISO-1 and FDG uptake with MR-based volumetric measures of tumor growth. In addition, [(18)F]ISO-1 and FDG were used to assess the response of MNU-induced tumors to bexarotene and Vorozole therapy. In the mouse mammary 66 tumors, a strong linear correlation was observed between the [(18)F]ISO-1 tumor: background ratio and the proliferative status (P:Q ratio) of the tumor (R = 0.87). Similarly, measures of [(18)F]ISO-1 uptake in MNU-induced tumors significantly correlated (R = 0.68, P<0.003) with changes in tumor volume between consecutive MR imaging sessions. Our data suggest that PET studies of [(18)F]ISO-1 provide a measure of both the proliferative status and tumor growth rate, which would be valuable in designing an appropriate treatment strategy.

(18)F-FDG PET/CT for Diagnosis of Osteosclerotic and Osteolytic Vertebral Metastatic Lesions: Comparison with Bone Scintigraphy

Study Design

A retrospective study.

Purpose

The aims of this study were to investigate the diagnostic value of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in PET/computed tomography (CT) in the evaluation of spinal metastatic lesions.

Overview of Literature

Recent studies described limitations regarding how many lesions with abnormal ¹⁸F-FDG PET findings in the bone show corresponding morphologic abnormalities.

Methods

The subjects for this retrospective study were 227 patients with primary malignant tumors, who were suspected of having spinal metastases. They underwent combined whole-body ¹⁸F-FDG PET/CT scanning for evaluation of known neoplasms in the whole spine. ^99mTc-methylene diphosphonate bone scan was performed within 2 weeks following PET/CT examinations. The final diagnosis of spinal metastasis was established by histopathological examination regarding bone biopsy or magnetic resonance imaging (MRI) findings, and follow-up MRI, CT and ¹⁸F-FDG PET for extensively wide lesions with subsequent progression.

Results

From a total of 504 spinal lesions in 227 patients, 224 lesions showed discordant image findings. For 122 metastatic lesions with confirmed diagnosis, the sensitivity/specificity of bone scan and FDG PET were 84%/21% and 89%/76%, respectively. In 102 true-positive metastatic lesions, the bone scan depicted predominantly osteosclerotic changes in 36% and osteolytic changes in 19%. In 109 true-positive lesions of FDG PET, osteolytic changes were depicted predominantly in 38% while osteosclerotic changes were portrayed in 15%.

Conclusions

¹⁸F-FDG PET in PET/CT could be used as a substitute for bone scan in the evaluation of spinal metastasis, especially for patients with spinal osteolytic lesions on CT.

Effects of DNA ploidy and S-phase fraction on fluorine-18 FDG uptake of primary breast cancer lesions

BACKGROUND

Flow cytometry (FCM) evaluating DNA content is emerging as the tool to monitor cell proliferation and malignant potential in several cancers such as stomach, lung, and salivary gland tumor. The purpose of this study was to correlate (18)F-FDG uptake of dual-time-point (DTP) positron emission tomography (PET) imaging with DNA ploidy and S-phase fraction (SPF) in primary breast cancer lesions.

PATIENTS AND METHODS

Seventy-two consecutive female patients (mean age ± SD, 52.7 ± 11.1 years; range, 28-81 years) had undergone (18)F-FDG DTP PET/computed tomography (CT) imaging for staging of breast malignancy in our institution during a 5-month period. FCM was performed on fresh-frozen samples of specimens obtained from surgery. (18)F-FDG uptake was then compared with DNA content.

RESULTS

Forty-four malignant lesions were included in this study. On FCM, DNA aneuploidy was detected in 14 lesions (31.8%). The maximum standardized uptake values (SUV(max1) and SUV(max2)) (SUV(max1), 6.8 ± 4.6 vs. 3.4 ± 2.4; P = .017), (SUV(max2), 7.9 ± 5.7 vs. 3.6 ± 2.7; P = .015) and retention index (RI) (12.8 ± 11.6 vs. 2.4 ± 10.8; P = .010) were significantly higher in DNA aneuploidy cancer than in DNA diploidy cancer. The value of RI (11.3 ± 11.5 vs. 2.6 ± 11.2; P = .022) was significantly higher in high SPF (> 15%) breast cancer than in low SPF (≤ 15%) breast cancer.

CONCLUSIONS

High (18)F-FDG uptake in breast cancer might be an indicator of DNA aneuploidy and high SPF. We propose that (18)F-FDG PET/CT imaging may be a noninvasive and useful tool for predicting the DNA content in breast cancer.

(18)F-labelled fluorodeoxyglucose-positron emission tomography (FDG-PET) heterogeneity of response is prognostic in dabrafenib treated BRAF mutant metastatic melanoma

BACKGROUND

Little is known about the prevalence and clinical significance of heterogeneity of positron emission tomography with (18)F-labelled fluorodeoxyglucose-positron emission tomography (FDG-PET) response. We aim to determine the prevalence, and clinicopathologic correlates of intra-patient heterogeneity of FDG-PET response in metastatic melanoma treated with dabrafenib, and to determine whether heterogeneity predicts clinical outcome.

METHODS

Patients with BRAF mutant metastatic melanoma and ≥ 2 FDG avid lesions treated on the Phase I trial of dabrafenib at a single institution (n=23) were included. FDG-PET response was assessed by comparing baseline PET scans with scans at day 15. A heterogeneous response was defined as responding and new or metabolically progressing lesion(s) in a patient, or >10% of lesions with a stable metabolic response and responding lesions in a patient.

RESULTS

Six (26%) patients had a heterogeneous PET response. The median time to progression (TTP) was 7.4 months (95% confidence interval (CI): 6.5-8.3) for PET homogeneous responders and 3.0 months (95%CI: 0.6-5.4) for PET heterogeneous responders. There were no homogeneous non-responders. Age, BRAF mutation genotype, dose, and lactate dehydrogenase, did not predict for heterogeneity of PET response. Heterogeneity did not correlate with tumour response. Lung metastases were more likely to respond than other visceral metastatic sites.

CONCLUSIONS

Heterogeneous FDG-PET responses are common in metastatic melanoma treated with dabrafenib, and heterogeneity is associated with a shorter TTP. FDG-PET heterogeneity may predict molecular heterogeneity, and FDG-PET directed biopsies may facilitate investigation into mechanisms of resistance to signal pathway inhibitors.

Characterization of a high-resolution hybrid DOI detector for a dedicated breast PET/CT scanner

The aim of this study is to design and test a new high-resolution hybrid depth of interaction (DOI) detector for a dedicated breast PET/CT scanner. Two detectors have been designed and built. The completed detectors are based on a 14 × 14 array of 1.5 × 1.5 × 20 mm(3) unpolished lutetium orthosilicate scintillation crystals, with each element coated in a 50 μm layer of reflective material. The detector is read out from both ends using a position-sensitive photomultiplier tube (PSPMT) and a large active area (20 × 20 mm(2)) avalanche photodiode (APD) to enable acquisition of DOI information. Nuclear instrumentation modules were used to characterize the detectors' performances in terms of timing, intrinsic spatial resolution (ISR) and energy resolution, as well as DOI resolution with a dual-ended readout configuration. Measurements with the APD were performed at a temperature of 10 °C. All crystals were identified at all depths, even though the signal amplitude from the PSPMT decreases with depth away from it. We measured a timing resolution of 2.4 ns, and an average energy resolution of 19%. The mean ISR was measured to be 1.2 mm for crystals in the central row of the array for detectors in the face-to-face position. Two off-center positions were measured corresponding to 26° and 51° oblique photon incidence, and the mean ISR at these positions was 1.5 and 1.7 mm, respectively. The average DOI resolution across all crystals and depths was measured to be 2.9 mm (including the beam width of 0.6 mm). This detector design shows good promise as a high-resolution detector for a dedicated breast PET/CT scanner.

The role of breast MRI in the investigation of anti-Yo positive paraneoplastic cerebellar degeneration

Paraneoplastic neurological syndromes are a group of rare and heterogeneous disorders complicating cancer through immune-mediated mechanisms. They typically arise before the diagnosis of malignancy, thus constituting its first clinical manifestation. A thorough search for the underlying tumour is necessary, as adequate tumour management is essential for both neurological prognosis and overall survival. The authors present the case of a 43 year-old woman who presented with a subacute cerebellar syndrome associated with the paraneoplastic anti-Yo antibody. Although paraneoplastic aetiology was immediately suspected, the diagnosis of the underlying tumour was not straightforward, as is often the case. This case report highlights the importance of directing tumour search for the most probable anatomic locations, according to patient demographics and risk factors as well as the type of onconeural antibodies present, and also the need to use the most sensitive diagnostic modalities appropriate for each target organ.

[Modern diagnostics in breast cancer: nuclear medicine techniques]

The authors discuss the role of nuclear medicine techniques in the modern diagnostics of breast cancer, including the methods currently used in Hungary and the future possibilities.

The value of 18-FDG PET/CT in early-stage breast cancer compared to traditional diagnostic modalities with an emphasis on changes in disease stage designation and treatment plan

BACKGROUND

Proper preoperative staging is vital in the treatment of breast cancer patients. The aim of our study was to assess the value of the diagnostic information provided by PET/CT in surgical practice in breast cancer cases considered early-stage by conventional diagnostic modalities.

METHODS

Whole-body 18-FDG PET/CT was performed on 115 breast cancer patients in whom traditional diagnostic modalities showed no signs of distant metastases or extensive axillary and/or extra-axillary lymphatic spreading, and the size of the primary tumor was <4 cm.

RESULTS

The sensitivity of PET/CT in the detection of the primary tumor was 93%. The sensitivity of the traditional diagnostic modalities in the detection of multifocality was 43.8% while that of PET/CT was 100% (p < 0.001). In the assessment of axillary lymph nodes, ultrasound had a sensitivity of 30% and a specificity of 95%. The corresponding estimates for PET/CT were 72% and 96%, respectively. PET/CT detected distant metastases in 8 patients. TNM classification was modified after PET/CT scanning in 54 patients (47%). PET/CT data changed the treatment plan established upon the results of traditional imaging modalities in 18 patients (15.6%).

CONCLUSIONS

PET/CT is able to assess primary tumor size and axillary lymphatic status more accurately than traditional diagnostic methods. It can detect distant metastases in 7-8% of those patients who were declared free of metastasis by clinical investigations. PET/CT scan modifies the disease stage determined by traditional diagnostic modalities in almost half of the patients and leads to a change in the treatment plan in every 6th patient.

Primary epithelioid trophoblastic tumor with a synchronous breast carcinoma detected only with FDG-PET/CT Scan

Epithelioid trophoblastic tumor is a recently described, rare and distinctive type of gestational trophoblastic tumor. We report the case of a 31-year old patient who had a full-term pregnancy 18 months before presentation. She had a right axillary lymph node metastasis and was referred for FDG-PET/CT scan for evaluation of distant metastasis and to detect primary malignancy. The axillary lymph node biopsy revealed metastatic breast carcinoma. FDG-PET/CT revealed increased uptake of right axillary lymph node, soft tissue density lesion with a diameter of 24 mm on left cervical region with increased FDG uptake, increased uptake on cervical region and left inguinal lymph node with increased uptake. Pelvic MRI imaging and ultrasonography were negative for malignancy in cervical region. Biopsy of the lesion was consistent with epithelioid trophoblastic tumor in cervical region. Gestational trophoblastic tumor was not suspected because she had no signs such as abnormal vaginal bleeding. FDG-PET/CT demonstrated the primary lesion in cervical region. We report a rare case of primary epithelioid trophoblastic tumor detected only with FDG-PET/CT scan which synchronized with breast carcinoma.

Radiopharmacological evaluation of 6-deoxy-6-[18F]fluoro-D-fructose as a radiotracer for PET imaging of GLUT5 in breast cancer

INTRODUCTION

Several clinical studies have shown low or no expression of GLUT1 in breast cancer patients, which may account for the low clinical specificity and sensitivity of 2-deoxy-2-[(18)F]fluoro-D-glucose ([(18)F]FDG) used in positron emission tomography (PET). Therefore, it has been proposed that other tumor characteristics such as the high expression of GLUT2 and GLUT5 in many breast tumors could be used to develop alternative strategies to detect breast cancer. Here we have studied the in vitro and in vivo radiopharmacological profile of 6-deoxy-6-[(18)F]fluoro-D-fructose (6-[(18)F]FDF) as a potential PET radiotracer to image GLUT5 expression in breast cancers.

METHODS

Uptake of 6-[(18)F]FDF was studied in murine EMT-6 and human MCF-7 breast cancer cells over 60 min and compared to [(18)F]FDG. Biodistribution of 6-[(18)F]FDF was determined in BALB/c mice. Tumor uptake was studied with dynamic small animal PET in EMT-6 tumor-bearing BALB/c mice and human xenograft MCF-7 tumor-bearing NIH-III mice in comparison to [(18)F]FDG. 6-[(18)F]FDF metabolism was investigated in mouse blood and urine.

RESULTS

6-[(18)F]FDF is taken up by EMT-6 and MCF-7 breast tumor cells independent of extracellular glucose levels but dependent on the extracellular concentration of fructose. After 60 min, 30±4% (n=9) and 12±1% (n=7) ID/mg protein 6-[(18)F]FDF was found in EMT-6 and MCF-7 cells, respectively. 6-deoxy-6-fluoro-d-fructose had a 10-fold higher potency than fructose to inhibit 6-[(18)F]FDF uptake into EMT-6 cells. Biodistribution in normal mice revealed radioactivity uptake in bone and brain. Radioactivity was accumulated in EMT-6 tumors reaching 3.65±0.30% ID/g (n=3) at 5 min post injection and decreasing to 1.75±0.03% ID/g (n=3) at 120 min post injection. Dynamic small animal PET showed significantly lower radioactivity uptake after 15 min post injection in MCF-7 tumors [standard uptake value (SUV)=0.76±0.05; n=3] compared to EMT-6 tumors (SUV=1.23±0.09; n=3). Interestingly, [(18)F]FDG uptake was significantly different in MCF-7 tumors (SUV(15 min) 0.74±0.12 to SUV(120 min) 0.80±0.15; n=3) versus EMT-6 tumors (SUV(15 min) 1.01±0.33 to SUV(120 min) 1.80±0.25; n=3). 6-[(18)F]FDF was shown to be a substrate for recombinant human ketohexokinase, and it was metabolized rapidly in vivo.

CONCLUSION

Based on the GLUT5 specific transport and phosphorylation by ketohexokinase, 6-[(18)F]FDF may represent a novel radiotracer for PET imaging of GLUT5 and ketohexokinase-expressing tumors.

18F-FDG PET/CT imaging in oncology

Accurate diagnosis and staging are essential for the optimal management of cancer patients. Positron emission tomography with 2-deoxy-2-[fluorine-18]fluoro-D-glucose integrated with computed tomography (18F-FDG PET/CT) has emerged as a powerful imaging tool for the detection of various cancers. The combined acquisition of PET and CT has synergistic advantages over PET or CT alone and minimizes their individual limitations. It is a valuable tool for staging and restaging of some tumors and has an important role in the detection of recurrence in asymptomatic patients with rising tumor marker levels and patients with negative or equivocal findings on conventional imaging techniques. It also allows for monitoring response to therapy and permitting timely modification of therapeutic regimens. In about 27% of the patients, the course of management is changed. This review provides guidance for oncologists/radiotherapists and clinical and surgical specialists on the use of 18F-FDG PET/CT in oncology.

Inflammatory breast cancer: the disease, the biology, the treatment

Inflammatory breast cancer (IBC) is a rare and aggressive form of invasive breast cancer accounting for 2.5% of all breast cancer cases. It is characterized by rapid progression, local and distant metastases, younger age of onset, and lower overall survival compared with other breast cancers. Historically, IBC is a lethal disease with less than a 5% survival rate beyond 5 years when treated with surgery or radiation therapy. Because of its rarity, IBC is often misdiagnosed as mastitis or generalized dermatitis. This review examines IBC's unique clinical presentation, pathology, epidemiology, imaging, and biology and details current multidisciplinary management of the disease, which comprises systemic therapy, surgery, and radiation therapy.

Normal Physiologic and Benign Foci with F-18 FDG Avidity on PET/CT in Patients with Breast Cancer

PURPOSE

The aim of this study was to evaluate the physiologic and benign F-18 fluorodeoxyglucose (FDG) avid foci in patients with breast cancer.

METHODS

On 309 F-18 FDG PET/CT scans of 241 women with breast cancer, the hypermetabolic lesions compared with the surrounding normal region were evaluated retrospectively. Available reports of other relevant radiological imaging, medical records, and follow-up PET/CT were reviewed for explanations of the abnormal uptake.

RESULTS

Among the 70 physiologic foci, muscular uptake of the lower neck following the surgical and/or radiation therapy of ipsilateral breast (29%), hypermetabolic ovaries (16%) and uterine (10%) uptake during the ovulatory and menstrual phases during the normal menstrual cycle were identified, and also hypermetabolic brown fat in cold-induced thermogenesis (7%), non-specific bowel uptake (35%) were observed. Among the 147 benign lesions, sequelae of the chest wall and breasts following surgical and/or radiation therapy, were often observed (27%). Hypermetabolic thyroid glands were noted as adenomas and chronic thyroiditis (18%). Reactive hyperplasia of cervical or mediastinal lymph nodes (32%), degenerative osteoarthritis and healed fractures (15%), hypermetabolic benign lung lesions (6%) were observed.

CONCLUSION

Altered physiologic and benign F-18 FDG uptake in the lower cervical muscle and chest wall following ipsilateral breast surgery or radiotherapy were common, and also normal physiologic uptake in ovary and uterus, brown fat, thyroid were considered as predominant findings in women patients with breast cancer. Knowledge of these findings might aid in the interpretation of FDG PET/CT in patients with breast cancer.

Detecting treatment response in a model of human breast adenocarcinoma using hyperpolarised [1-13C]pyruvate and [1,4-13C2]fumarate

BACKGROUND

The recent introduction of a dynamic nuclear polarisation technique has permitted noninvasive imaging of tumour cell metabolism in vivo following intravenous administration of (13)C-labelled cell substrates.

METHODS

Changes in hyperpolarised [1-(13)C]pyruvate and [1,4-(13)C(2)]fumarate metabolism were evaluated in both MDA-MB-231 cells and in implanted MDA-MB-231 tumours following doxorubicin treatment.

RESULTS

Treatment of MDA-MB-231 cells resulted in the induction of apoptosis, which was accompanied by a decrease in hyperpolarised (13)C label flux between [1-(13)C]pyruvate and lactate, which was correlated with a decrease in the cellular NAD(H) coenzyme pool. There was also an increase in the rate of fumarate conversion to malate, which accompanied the onset of cellular necrosis. In vivo, the decrease in (13)C label exchange between pyruvate and lactate and the increased flux between fumarate and malate, following drug treatment, were shown to occur in the absence of any detectable change in tumour size.

CONCLUSION

We show here that the early responses of a human breast adenocarcinoma tumour model to drug treatment can be followed by administration of both hyperpolarised [1-(13)C]pyruvate and [1,4-(13)C(2)]fumarate. These techniques could be used, therefore, in the clinic to detect the early responses of breast tumours to treatment.