MRI fused with prone FDG PET/CT improves the primary tumour staging of patients with breast cancer

Objective

Our aim was to evaluate the diagnostic accuracy of magnetic resonance imaging (MRI) fused with prone 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) in primary tumour staging of patients with breast cancer.

Methods

This retrospective study evaluated 45 women with 49 pathologically proven breast carcinomas. MRI and prone PET-CT scans with time-of-flight and point-spread-function reconstruction were performed with the same dedicated breast coil. The studies were assessed by a radiologist and a nuclear medicine physician, and evaluation of fused images was made by consensus. The final diagnosis was based on pathology (90 lesions) or follow-up?≥?24 months (17 lesions).

Results

The study assessed 72 malignant and 35 benign lesions with a median size of 1.8 cm (range 0.3–8.4 cm): 31 focal, nine multifocal and nine multicentric cases. In lesion-by-lesion analysis, sensitivity, specificity, positive and negative predictive values were 97%, 80%, 91% and 93% for MRI, 96%, 71%, 87%, and 89% for prone PET, and 97%. 94%, 97% and 94% for MRI fused with PET. Areas under the curve (AUC) were 0.953, 0.850, and 0.983, respectively (p?<?0.01).

Conclusions

MRI fused with FDG-PET is more accurate than FDG-PET in primary tumour staging of breast cancer patients and increases the specificity of MRI.

Key points

? FDG PET-CT may improve the specificity of MRI in breast cancer staging.? MRI fused with prone 2-[fluorine-18]-fluoro-2-deoxy-D-glucose PET-CT has better overall diagnostic performance than MRI.? The clinical role of fused PET-MRI has not yet been established.

     

Whole-body PET/CT-mammography for staging breast cancer: initial results

The purpose of this study was to evaluate the feasibility and utility of a dedicated positron emission tomography (PET)/CT protocol in breast cancer patients. 40 patients with suspected recurrent breast cancer underwent whole-body PET/CT in the supine position (SP) followed by PET/CT of the breasts and axillae in the prone position (PP) using a special positioning aid. PP and SP images were compared in terms of the tumour-to-thoracic-wall distance, tumour-to-skin distance and tumour volume, diameter, density, maximal standardized uptake value (SUV(max)) and localization. The size of axillary areas, the number of intra-axillary lymph nodes, their transverse diameters, their SUV(max) and the number of distant metastases were compared between PP and SP images. Differences were tested for significance using the Student's t-test. All patients tolerated PP imaging well. Five locally recurrent breast cancers were detected, both in the SP and in the PP. Mean tumour-to-thoracic-wall distances (PP, 19 mm; SP, 8 mm; p = 0.003) and tumour-to-skin distances (PP, 10 mm; SP, 7 mm; p = 0.013) were significantly larger in the PP than in the SP. Potential thoracic wall or skin infiltration, as well as quadrant localization, were determined more easily in PP. The axillary area was wider in the PP when compared with SP (PP, 14.4 cm(2); SP, 10.6 cm(2); p<0.001). No other parameters were significantly different. In conclusion, a dedicated whole-body PET/CT examination, including PET/CT mammography, is feasible for clinical practice and may offer important information on the possible infiltration of a breast lesion into the adjacent thoracic wall and skin. Even though the axilla may be delineated more clearly in the PP, there seems to be no benefit with regard to N-staging.     

Comparative study of FDG PET/CT and conventional imaging in the staging of rhabdomyosarcoma

Objective  The current study was conducted to compare the diagnostic accuracy between ¹⁸F-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET)/computed tomography (CT), and conventional imaging (CI) for the staging and re-staging of patients with rhabdomyosarcomas. Methods  Thirty-five patients who underwent FDG PET/CT prior to treatment were evaluated retrospectively. CI methods consisted of ^99mTc-hydroxymethylene diphosphonate bone scintigraphy, chest radiograph, whole body CT, and magnetic resonance imaging of the primary site. The images were reviewed and two boardcertified radiologists reached a diagnostic consensus. Tumor stage was confirmed by histological examination and/or follow-up examinations. Results  Interpretation on the basis of FDG PET/CT, and CI, diagnostic accuracies of the T and N stages were similar. Using FDG PET/CT, the M stage was correctly assigned in 31 patients (89%), whereas the accuracy of CI in M stage was 63%. TNM stage was correctly assessed with FDG PET/CT in 30 of 35 patients (86%) and with CI in 19 of 35 patients (54%). The overall TNM staging and M staging accuracies of FDG PET/CT were significantly higher than that of CI (P < 0.01). Conclusions  FDG PET/CT is more accurate than CI regarding clinical staging and re-staging of patients with rhabdomyosarcomas.     

Diagnostic value of full-dose FDG PET/CT for axillary lymph node staging in breast cancer patients

Purpose

The aims of this study were (1) to evaluate FDG PET/CT and CT for the detection of axillary lymph node metastases in breast cancer (BC) patients and (2) to evaluate FDG PET/CT as a pre-test for the triage to sentinel lymph node biopsy (SLNB) versus axillary lymph node dissection (ALND).

Methods

The sensitivity, specificity, positive and negative predictive value (PPV, NPV), and accuracy of FDG PET/CT and CT for axillary lymph node metastases were determined in 61 patients (gold standard: histopathology). According to the equation “NPV = specificity ? (1-prevalence) / [specificity ? (1-prevalence) + (1-sensitivity) ? prevalence]” FDG PET/CT was evaluated as a triage tool for SLNB versus ALND.

Results

The sensitivity, specificity, PPV, NPV and accuracy of FDG PET/CT was 58, 92, 82, 77 and 79% and of CT 46, 89, 72, 71 and 72%, respectively. Patients with an up to ~60% risk for axillary lymph node metastases appear to be candidates for SLNB provided that the axilla is unremarkable on FDG PET/CT.

Conclusion

FDG PET/CT cannot replace invasive approaches for axillary staging but may extend the indication for SLNB.     

Diagnostic value of diffusion-weighted magnetic resonance imaging (DWI) compared to FDG PET/CT for whole-body breast cancer staging

Purpose

The aim of the study was to prospectively compare the diagnostic value of whole-body diffusion-weighted imaging (DWI) and FDG PET/CT for breast cancer (BC) staging.

Methods

Twenty BC patients underwent whole-body FDG PET/CT and 1.5-T DWI. Lesions with qualitatively elevated signal intensity on DW images (b?=?800 s/mm²) were rated as suspicious for tumour and mapped to individual lesions and different compartments (overall 552 lesions). The apparent diffusion coefficient (ADC) value was determined for quantitative evaluation. Histopathology, MRI findings, bone scan findings, concordant findings between FDG PET/CT and DWI, CT follow-up scans and plausibility served as the standards of reference defining malignancy.

Results

According to the standards of reference, breasts harboured malignancy in 11, regional lymph nodes in 4, M1 lymph nodes in 3, bone in 7, lung in 2, liver in 3 and other tissues in 3 patients. On a compartment basis, the sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) for the detection of malignancies were 94, 99, 98, 97 and 98% for FDG PET/CT and 91, 72, 76, 50 and 96% for DWI, respectively. Of the lesions seen on DWI only, 348 (82%) turned out to be false-positive compared to 23 (11%) on FDG PET/CT. The average lesion ADC was 820?±?300 with true-positive lesions having 929?±?252 vs 713?±?305 in false-positive lesions (p?<?0.0001).

Conclusion

Based on these initial data DWI seems to be a sensitive but unspecific modality for the detection of locoregional or metastatic BC disease. There was no possibility to quantitatively distinguish lesions using ADC. DWI alone may not be recommended as a whole-body staging alternative to FDG PET(/CT). Further studies are necessary addressing the question of whether full-body MRI including DWI may become an alternative to FDG PET/CT for whole-body breast cancer staging.     

False-positive lesions mimicking breast cancer on FDG PET and PET/CT

OBJECTIVE: Incidental (18)F-FDG-avid breast lesions are commonly encountered in patients with cancer who undergo staging PET/CT. This pictorial essay discusses breast lesions that show increased FDG activity, mimicking breast cancer, with biopsy-confirmed benign diagnosis. CONCLUSION: Acute and chronic inflammation, physiologic lactation, and benign breast masses, including silicone granuloma, fat necrosis, fibroadenoma, and postsurgical changes, may show increased FDG uptake on PET/CT. These conditions can often be differentiated from malignancy by correlative imaging, including mammography, sonography, or MRI.     

Whole-body (18)F-FDG PET and conventional imaging for predicting outcome in previously treated breast cancer patients.

This study was conducted to determine the ability of (18)F-FDG PET and conventional imaging (CI) to predict the outcomes in breast cancer patients who have previously undergone primary treatment. METHODS: The study population consisted of 61 female patients (median age, 54 y; range, 32--91 y) who were reevaluated with (18)F-FDG PET and CI after treatment. The median interval between the last treatment and PET was 0.4 y (range, 0--16 y). PET was performed within 3 mo of CI (median interval, 25 d; range, 2--84 d). To determine the independent impact of PET on outcome, PET images were reinterpreted in a blind fashion. Availability of clinical information after PET scanning (21 plus minus 12 mo) was required for study inclusion. Study endpoints were clinical evidence of progression of disease or death. RESULTS: Of 61 patients, 19 (31.1%) had no clinical evidence and 38 (62.3%) had evidence of residual or recurrent disease by the end of follow-up. Four patients (6.6%) had died. The positive and negative predictive values (PPV and NPV, respectively) of PET were 93% and 84%, respectively. CI yielded a PPV of 85% and an NPV of 59%. The prognostic accuracy of single whole-body PET was superior to that of multiple procedures with CI (90% vs. 75%; P < 0.05). Kaplan--Meier estimates of disease-free survival in patients with negative PET findings compared with those with positive PET findings revealed a significant difference between the 2 curves (log-rank test = 0.001). Kaplan--Meier estimates of disease-free survival stratified by CI results showed a marginally significant difference between CI-positive and CI-negative patients (log-rank test = 0.04). CONCLUSION: FDG PET can be used to improve prediction of the clinical outcome of previously treated breast cancer patients relative to what is achievable through CI alone.     

Whole-body FDG positron emission tomographic imaging for staging esophageal cancer comparison with computed tomography

PURPOSE: The aim of the authors in this study was to critically evaluate the role of whole-body positron emission tomographic (PET) imaging with fluorine-18 fluorodeoxyglucose (FDG) in staging esophageal cancer, and further to compare this method with conventional imaging with computed tomography (CT). MATERIALS AND METHODS: The authors performed independent, blinded retrospective evaluations of FDG PET images obtained in 47 patients referred for the initial staging of esophageal cancer before minimally invasive surgical staging. Twenty PET studies from patients with nonesophageal thoracic cancers were randomly selected for inclusion in the PET readings. In a subset of 37 of 47 cases, the PET findings were compared with independent readings of CT studies acquired within the same 6-week interval. The utility of the imaging findings was evaluated using a high-sensitivity interpretation (i.e., assigning equivocal findings as positive) and a low-sensitivity interpretation (i.e., assigning equivocal findings as negative). RESULTS: PET was less sensitive (41% in high-sensitivity mode, 35% in low-sensitivity mode) than CT (63% to 87%) for diagnosing tumor involvement in locoregional lymph nodes, which was identified by surgical assessment in 72% of patients. Notable, however, was the greater specificity of PET-determined nodal sites (to approximately 90%) compared with CT (14% to 43%). In detecting histologically proved distant metastases (n = 10), PET performed considerably better when applied in the high-sensitivity mode, with a sensitivity rate of approximately 70% and a specificity rate of more than 90% in the total group and in the subset of patients with correlative CT data. In the low-sensitivity mode, CT identified only two of seven metastatic sites, whereas the high-sensitivity mode resulted in an unacceptably high rate of false-positive readings (positive predictive value, 29%). PET correctly identified one additional site of metastasis that was not detected by CT. CONCLUSIONS: The relatively low sensitivity of PET for identifying locoregional lesions precludes its replacement of conventional CT staging. However, the primary advantage of PET imaging is its superior specificity for tumor detection and improved diagnostic value for distant metastatic sites, features that may substantially affect patient management decisions. In conclusion, PET imaging is useful in the initial staging of esophageal cancer and provides additional and complementary information to that obtained by CT imaging.     

18F-FDG PET/CT imaging versus dynamic contrast-enhanced CT for staging and prognosis of inflammatory breast cancer

Purpose

Inflammatory breast cancer (IBC) is the most aggressive type of breast cancer with a poor prognosis. Locoregional staging is based on dynamic contrast-enhanced (DCE) CT or MRI. The aim of this study was to compare the performances of FDG PET/CT and DCE CT in locoregional staging of IBC and to assess their respective prognostic values.

Methods

The study group comprised 50 women (median age: 51?±?11 years) followed in our institution for IBC who underwent FDG PET/CT and DCE CT scans (median interval 5?±?9 days). CT enhancement parameters were net maximal enhancement, net early enhancement and perfusion.

Results

The PET/CT scans showed intense FDG uptake in all primary tumours. Concordance rate between PET/CT and DCE CT for breast tumour localization was 92 %. No significant correlation was found between SUVmax and CT enhancement parameters in primary tumours (p?>?0.6). PET/CT and DCE CT results were poorly correlated for skin infiltration (kappa?=?0.19). Ipsilateral foci of increased axillary FDG uptake were found in 47 patients (median SUV: 7.9?±?5.4), whereas enlarged axillary lymph nodes were observed on DCE CT in 43 patients. Results for axillary node involvement were fairly well correlated (kappa?=?0.55). Nineteen patients (38 %) were found to be metastatic on PET/CT scan with a significant shorter progression-free survival than patients without distant lesions (p?=?0.01). In the primary tumour, no statistically significant difference was observed between high and moderate tumour FDG uptake on survival, using an SUVmax cut-off of 5 (p?=?0.7 and 0.9), or between high and low tumour enhancement on DCE CT (p?>?0.8).

Conclusion

FDG PET/CT imaging provided additional information concerning locoregional involvement to that provided by DCE CT on and allowed detection of distant metastases in the same whole-body procedure. Tumour FDG uptake or CT enhancement parameters were not correlated and were not found to have any prognostic value.     

FDG PET/CT of a late-term pregnant woman with breast cancer

A 38-year-old pregnant woman at 26-week gestation with left breast cancer requested an FDG PET/CT scan for more detailed staging of her breast cancer before treatment. After discussing the potential radiation-related risk and estimating possible absorbed dose to fetus, she consented for examination. By using a low-radiation-dose CT protocol and administration of routine 370-MBq FDG without diuresis, the resultant calculated (using existing models to predict fetal radiation exposure) fetal dose from CT and FDG would be 3.60 mGy and 6.29 mGy, respectively. In contrast to the existing few literatures, our case also demonstrated previously unreported uptake in the fetal kidneys.     

Thyroid metastasis from primary renal cell cancer on FDG PET/CT

We report the PET/CT appearance of metastasis from primary renal cancer to the thyroid in a 52-year-old man with a history of right renal cell carcinoma, status postright nephrectomy, recently presented biopsied-proven metastatic lesion in his left thyroid lobe. Restaging PET/CT study demonstrates a 1.4 × 0.9 cm hypodense, moderately active lesion in the left thyroid lobe with a maximum SUV of 2.8. No other abnormal hypermetabolic lesion is seen in the right renal surgical bed or the remaining body. The patient has subsequently treated with Sutent (Sunitinib).     

Tumour markers and FDG PET/CT for prediction of disease relapse in patients with breast cancer

Purpose  

The aim of the study was to assess the role of CA 15.3, CT and positron emission tomography (PET)/CT in patients with breast cancer and suspected disease relapse after primary treatment.     

18F-FDG PET/CT provides powerful prognostic stratification in the primary staging of large breast cancer when compared with conventional explorations

Purpose

The objective of this study was to assess the impact on management and the prognostic value of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT for initial staging of newly diagnosed large breast cancer (BC) when compared with conventional staging.

Methods

We prospectively included 142 patients with newly diagnosed BC and at least grade T2 tumour. All patients were evaluated with complete conventional imaging (CI) procedures (mammogram and/or breast ultrasound, bone scan, abdominal ultrasound and/or CT, X-rays and/or CT of the chest), followed by FDG PET/CT exploration, prior to treatment. The treatment plan based on CI staging was compared with that based on PET/CT findings. CI and PET/CT findings were confirmed by imaging and clinical follow-up and/or pathology when assessable. Progression-free survival (PFS) was analysed using the Cox proportional hazards regression model.

Results

According to CI staging, 79 patients (56 %) were stage II, 46 (32 %) stage III and 17 (12 %) stage IV (distant metastases). Of the patients, 30 (21 %) were upstaged by PET/CT, including 12 (8 %) from stage II or III to stage IV. On the other hand, 23 patients (16 %) were downstaged by PET/CT, including 4 (3 %) from stage IV to stage II or III. PET/CT had a high or medium impact on management planning for 18 patients (13 %). Median follow-up was 30 months (range 9–59 months); 37 patients (26 %) experienced recurrence or progression of disease during follow-up and 17 patients (12 %) died. The Cox model indicated that CI staging was significantly associated with PFS (p?=?0.01), but PET/CT staging provided stronger prognostic stratification (p?<?0.0001). Moreover, Cox regression multivariate analysis showed that only PET/CT staging remained associated with PFS (p?<?0.0001).

Conclusion

FDG PET/CT provides staging information that more accurately stratifies prognostic risk in newly diagnosed large BC when compared with conventional explorations alone.