Anatomical and functional volume concordance between FDG PET,and T2 and diffusion-weighted MRI for cervical cancer: a hybrid PET/MR study

Purpose

To evaluate the concordance among ¹⁸F-FDG PET imaging, MR T2-weighted (T2-W) imaging and apparent diffusion coefficient (ADC) maps with diffusion-weighted (DW) imaging in cervical cancer using hybrid whole-body PET/MR.

Methods

This study prospectively included 35 patients with cervical cancer who underwent pretreatment ¹⁸F-FDG PET/MR imaging. ¹⁸F-FDG PET and MR images were fused using standard software. The percent of the maximum standardized uptake values (SUV_max) was used to contour tumours on PET images, and volumes were calculated automatically. Tumour volumes measured on T2-W and DW images were calculated with standard techniques of tumour area multiplied by the slice profile. Parametric statistics were used for data analysis.

Results

FDG PET tumour volumes calculated using SUV_max (14.30?±?4.70) and T2-W imaging volume (33.81?±?27.32 cm³) were similar (P?>?0.05) at 35 % and 40 % of SUV_max (32.91?±?18.90 cm³ and 27.56?±?17.19 cm³ respectively) and significantly correlated (P?<?0.001; r?=?0.735 and 0.766). The mean DW volume was 30.48?±?22.41 cm³. DW volumes were not significantly different from FDG PET volumes at either 35 % SUV_max or 40 % SUV_max or from T2-W imaging volumes (P?>?0.05). PET subvolumes with increasing SUV_max cut-off percentage showed an inverse change in mean ADC values on DW imaging (P?<?0.001, ANOVA).

Conclusion

Hybrid PET/MR showed strong volume concordance between FDG PET, and T2-W and DW imaging in cervical cancer. Cut-off at 35 % or 40 % of SUV_max is recommended for ¹⁸F-FDG PET/MR SUV-based tumour volume estimation. The linear tumour subvolume concordance between FDG PET and DW imaging demonstrates individual regional concordance of metabolic activity and cell density.     

Follow-up of women with breast cancer: comparison between MRI and FDG PET

The aim of this study was to compare MRI of the breast with ¹⁸F-fluoro-deoxy-glucose (FDG) positron emission tomography (PET) in patients with suspected local or regional breast cancer recurrence or suspected contralateral breast cancer. Thirty-two patients (mean age 57.2 years, age range 32–76 years) with suspected loco-regional recurrence (n=19), chest wall recurrence (n=5), and suspected secondary tumor of the contralateral breast (n=8) underwent MRI of the breast and FDG PET of the whole body and breast region. Cytology/histology (n=17) or a clinical follow-up examination (n=15) with additional imaging served as the standard of reference. A McNemar test was performed to compare PET and MRI, and kappa was determined to quantify agreement of both methods. Sensitivity was 79 and 100%, specificity was 94 and 72%, and accuracy was 88 and 84% for MRI and PET, respectively. Additional metastases outside the field of view of MRI were found in PET in 5 patients. In this study both imaging methods had comparable accuracy. The detection of distant metastases with whole-body PET imaging can influence patient management.     

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.     

PET/MRI of the breast

The future clinical use of the combination of positron emission tomography (PET) with 2-Fluoro[F-18]-2-Deoxy-d-Glucose (FDG)and MRI is still unclear. If a patient requires a PET and breast DCE-MRI for staging purposes, both scans can be done in the same visit. In the breast, DCE-MRI is better at lesion detection (sensitivity), margin evaluation, and has a higher specificity than CT. The potential for multiparametric qualitative and quantitative imaging is also an advantage of PET/MRI which provides opportunity to improve tumor characterization and may ultimately lead to outcome prediction. This review discusses technical and clinical aspects of this emerging technology in breast cancer patients.     

Maternal-fetal in vivo imaging: a combined PET and MRI study.

An understanding of how drugs are transferred between mother and fetus during the gestational period is an important medical issue of relevance to both therapeutic drugs and drugs of abuse. Though there are several in vitro and in vivo methods to examine this issue, all have limitations. Furthermore, ethical and safety considerations generally preclude such studies in pregnant humans. PET and appropriately labeled compounds have the ability to provide information on both maternal-fetal drug pharmacokinetics and pharmacodynamics. We present here a nonhuman primate animal model and the methodology for combining PET and MRI to identify fetal organs and to measure maternal and fetal isotope distribution using (18)F-FDG and a whole-body imaging protocol to demonstrate proof-of-principle. METHODS: One nonpregnant nonhuman primate was used for determination of the anesthesia protocol and MRI methods and 3 pregnant nonhuman primates (Macaques radiata) weighing 4.5-7 kg were used for the imaging study and anesthetized with propofol (160-300 micro g/kg/min). Anatomic T2-weighted MR images were acquired on a 4-T MR instrument. Subsequently, whole-body PET images were acquired 35 min after injection of (18)F-FDG, and standardized uptake values (SUVs) were calculated. Image processing and coregistration were performed using commercial software. RESULTS: All animals underwent uneventful general anesthesia for a period of up to 7 h. Coregistration of PET and MR images allowed identification of fetal organs and demonstrated that (18)F-FDG readily crosses the placenta and that (18)F accumulates in both maternal and fetal brain, heart, and bladder. Brain SUVs averaged 1.95 +/- 0.08 (mean +/- SD) and 1.58 +/- 0.11 for mothers and fetuses, respectively. Monkeys delivered healthy babies after a normal gestational term of 170 d following the PET/MRI study. CONCLUSION: The pregnant macaque in combination with PET and MRI technology allows the measurement of radioisotope distribution in maternal and fetal organs. This demonstrates the potential for noninvasively measuring the transfer of drugs across the placenta and for measuring the fetal drug distribution. It also opens up the possibility for studying binding and elimination as well as the effects of a drug on specific cellular elements and physiologic processes during the gestational period in a primate model.     

Performance of preoperative breast MRI based on breast cancer molecular subtype

PurposeTo assess the performance of preoperative breast MRI biopsy recommendations based on breast cancer molecular subtype.MethodsAll preoperative breast MRIs at a single academic medical center from May 2010 to March 2014 were identified. Reports were reviewed for biopsy recommendations. All pathology reports were reviewed to determine biopsy recommendation outcomes. Molecular subtypes were defined as Luminal A (ER/PR+ and HER2-), Luminal B (ER/PR+ and HER2+), HER2 (ER-, PR- and HER2+), and Basal (ER-, PR-, and HER2-). Logistic regression assessed the probability of true positive versus false positive biopsy and mastectomy versus lumpectomy.ResultsThere were 383 patients included with a molecular subtype distribution of 253 Luminal A, 44 Luminal B, 20 HER2, and 66 Basal. Two hundred and thirteen (56%) patients and 319 sites were recommended for biopsy. Molecular subtype did not influence the recommendation for biopsy (p = 0.69) or the number of biopsy site recommendations (p = 0.30). The positive predictive value for a biopsy recommendation was 42% overall and 46% for Luminal A, 43% for Luminal B, 36% for HER2, and 29% for Basal subtype cancers. The multivariate logistic regression model showed no difference in true positive biopsy rate based on molecular subtype (p = 0.78). Fifty-one percent of patients underwent mastectomy and the multivariate model demonstrated that only a true positive biopsy (odds ratio: 5.3) was associated with higher mastectomy rates.ConclusionBreast cancer molecular subtype did not influence biopsy recommendations, positive predictive values, or surgical approaches. Only true positive biopsies increased the mastectomy rate.     

PET/MRI: Multiparametric imaging of brain tumors

A combination of morphological imaging of the brain with microstructural and functional imaging provides a comprehensive overview of the properties of individual tissues. While diffusion weighted imaging provides information about tissue cellularity, spectroscopic imaging allows us to evaluate the integrity of neurons and possible anaerobic glycolysis during tumor hypoxia, in addition to the presence of accelerated synthesis or degradation of cellular membranes; on the other hand, PET metabolic imaging is used to evaluate major metabolic pathways, determining the overall extent of the tumor (¹⁸F-FET, ¹⁸F-FDOPA, ¹⁸F-FCH) or the degree of differentiation (¹⁸F-FDG, ¹⁸F-FLT, ¹⁸F-FDOPA and ¹⁸F-FET). Multi-parameter analysis of tissue characteristics and determination of the phenotype of the tumor tissue is a natural advantage of PET/MRI scanning. The disadvantages are higher cost and limited availability in all centers with neuro-oncology surgery. PET/MRI scanning of brain tumors is one of the most promising indications since the earliest experiments with integrated PET/MRI imaging systems, and along with hybrid imaging of neurodegenerative diseases, represent a new direction in the development of neuroradiology on the path towards comprehensive imaging at the molecular level.     

乳腺癌18F-FDG PET/CT和3.0T MRI联合显像评分与Ki-67表达水平的相关性分析

目的 探讨18F-FDG PET/CT和3.0T MRI联合显像评分与Ki-67（一种增殖细胞核抗原）表达水平的相关性。 方法 18例经病理确诊的原发性乳腺癌患者术前行18F-FDG PET/CT和3.0T MRI联合显像,对显像结果进行评分并与Ki-67的表达水平进行相关性分析。联合显像和术后病理标本的免疫组化检测在一周内完成。 结果 ① 乳腺癌最大标准化摄取值与Ki-67的表达水平呈正相关（r=0.473,P＜0.05）;②PET/CT和3.0T MRI联合显像评分与Ki-67的表达水平呈明显正相关（r=0.674,P＜0.01）。 结论 18F-FDG PET/CT和3.0T MRI联合显像在乳腺癌的预后判断中可能具有重要的潜在价值。     

MRI、MRS及11C-胆碱PET/CT对前列腺癌诊断的对比研究

目的 探讨11C-胆碱PET/CT对前列腺癌的诊断价值,并与常规MRI及直肠线圈1H MR波谱分析(MRS)的诊断结果对比.方法 34例前列腺病变患者行11C-胆碱PET/CT、常规前列腺MRI及直肠线圈MRS检查.11C-胆碱PET/CT图像于注射5 min后获取.对前列腺良性病变和前列腺癌部位分别计算标准摄取值(SUV)最大值及平均值(SUVmax、SUVmean).将PET/CT诊断结果与MRI、1H MRS及病理检查结果对比.分析SUV与血清前列腺特异抗原(PSA)的相关性.病理检查结果为在开放式MR光学导引系统下穿刺活组织检查或经直肠指诊穿刺获得.转移灶经局部穿刺活组织检查或影像学随访证实.统计学处理采用SPSS 11.0软件.结果 (1)原发性前列腺癌SUVmax 5.72±2.31,SUVmean 4.78±2.20.SUV比较:低分化腺癌＞中分化腺癌＞高分化腺癌.前列腺良性病变的SUVmax 2.49±1.43,SUVmean 1.89±1.24.不同病理类型及分化程度的前列腺病变SUVmax、SUVmean之间差异无统计学意义(FSUVmax=2.401,FSUVmean=1.744;P＞0.05).前列腺癌SUV高于前列腺良性病变,但二者存在交叉重叠现象,如果以SUVmax 2.5为分界,则二者之间有25.8%(8/31)交叉.因此,前列腺的形态、前列腺内放射性分布的均匀程度对前列腺癌的诊断价值高于SUV.SUVmax与血清PSA之间呈正相关(等级相关系数rs=0.819 86,P＜0.01).(2)影像诊断与病理检查结果符合的例数11C-胆碱PET/CT为25例,MRI为21例,MRS为22例.11C-胆碱PET/CT、MRI及MRS诊断前列腺癌的灵敏度、特异性、阳性预测值、阴性预测值分别为 93.75%, 66.67%, 75.00%, 90.91%; 87.50%, 46.67%, 63.64%, 77.78%; 87.50%, 53.33%, 66.67%, 80.00%.3种方法比较差异无统计学意义(χ2=1.422,P＞0.05).(3)11C-胆碱PET/CT能区别前列腺癌治疗后复查患者复发区与治疗有效区,并可检出远处转移灶.结论 11C-胆碱PET/CT可用于前列腺癌的诊断、分期及检测复发和转移灶;其对前列腺癌的诊断灵敏度、特异性、阳性预测值、阴性预测值均略高于MRS及MRI;SUVmax与血清PSA之间呈正相关.     

Potential of hybrid 18F-fluorocholine PET/MRI for prostate cancer imaging

Purpose

To report the first results of hybrid ¹⁸F-fluorocholine PET/MRI imaging for the detection of prostate cancer.

Methods

This analysis included 26 consecutive patients scheduled for prostate PET/MRI before radical prostatectomy. The examinations were performed on a hybrid whole-body PET/MRI scanner. The MR acquisitions which included T2-weighted, diffusion-weighted and dynamic contrast-enhanced sequences were followed during the same session by whole-body PET scans. Parametric maps were constructed to measure normalized T2-weighted intensity (nT2), apparent diffusion coefficient (ADC), volume transfer constant (K ^trans), extravascular extracellular volume fraction (v _e) and standardized uptake values (SUV). With pathology as the gold standard, ROC curves were calculated using logistic regression for each parameter and for the best combination with and without PET to obtain a MR model versus a PETMR model.

Results

Of the 26 patients initially selected, 3 were excluded due to absence of an endorectal coil (2 patients) or prosthesis artefacts (1 patient). In the whole prostate, the area under the curve (AUC) for SUV_max, ADC, nT2, K ^trans and v _e were 0.762, 0.756, 0.685, 0.611 and 0.529 with a best threshold at 3.044 for SUV_max and 1.075 × 10^?3 mm²/s for ADC. The anatomical distinction between the transition zone and the peripheral zone showed the potential of the adjunctive use of PET. In the peripheral zone, the AUC of 0.893 for the PETMR model was significantly greater (p?=?0.0402) than the AUC of 0.84 for the MR model only. In the whole prostate, no relevant correlation was observed between ADC and SUV_max. The SUV_max was not affected by the Gleason score.

Conclusion

The performance of a hybrid whole-body ¹⁸F-fluorocholine PET/MRI scan in the same session combined with a prostatic MR examination did not interfere with the diagnostic accuracy of the MR sequences. The registration of the PET data and the T2 anatomical MR sequence data allowed precise localization of hypermetabolic foci in the prostate. While in the transition zone the adenomatous hyperplasia interfered with cancer detection by PET, the quantitative analysis tool performed well for cancer detection in the peripheral zone.     

PET/MRI hybrid imaging: devices and initial results

The combination of functional and morphological imaging technologies such as positron emission tomography (PET) and X-ray computed tomography (CT) has shown its value in the clinical and preclinical field. However, CT provides only very limited soft-tissue contrast and exposes the examined patient or laboratory animal to a high X-ray radiation dose. In comparison to CT, magnetic resonance tomography (MRI) provides excellent soft-tissue contrast and allows for nuclear magnetic resonance spectroscopy (NMRS) or functional MRI (fMRI). Thus, the combination of PET and MRI has been pursued for several years. First approaches have succeeded using conventional photo multiplier tube (PMT) technology together with light fibers to transfer scintillation light away from the high magnetic field. Latest PET/MRI developments use solid-state light detectors that can be operated even at high magnetic fields. Initial pilot studies with prototype animal PET/MRI systems have shown promising results by combining high resolution morphology with multifunctional information isochronously.     

功能磁共振成像在乳腺癌诊断中的应用

乳腺癌作为一种常见的恶性疾病,其早期诊断及疗效评价对病人的预后至关重要,以磁共振质子波谱分析、扩散加权成像、灌注加权成像为主要方式的功能磁共振成像对乳腺癌的诊断及早期评价化疗效果起重要作用,就各种功能磁共振成像的原理、技术参数及临床应用价值进行综述。     

功能磁共振成像在乳腺癌诊断中的应用

乳腺癌作为一种常见的恶性疾病,其早期诊断及疗效评价对病人的预后至关重要,以磁共振质子波谱分析、扩散加权成像、灌注加权成像为主要方式的功能磁共振成像对乳腺癌的诊断及早期评价化疗效果起重要作用,就各种功能磁共振成像的原理、技术参数及临床应用价值进行综述.     

PET with [18F]fluorothymidine for imaging of primary breast cancer: a pilot study

The aim of this study was to evaluate the use of [¹⁸F]fluorothymidine (FLT) as a positron emission tomography (PET) tracer for the diagnosis of breast cancer. To this end, 12 patients with 14 primary breast cancer lesions (T2–T4) were studied by FLT-PET. For comparison, [¹⁸F]fluorodeoxyglucose (FDG) PET scans were performed in six patients. Thirteen of the 14 primary tumours demonstrated focally increased FLT uptake (SUV_mean=3.4±1.1). Seven out of eight patients with histologically proven axillary lymph node metastases showed focally increased FLT uptake in the corresponding areas (SUV_mean=2.4±1.2). The lowest SUV (mean =0.7) was observed in one of two inflammatory cancers. The contrast between primary tumours or metastases and surrounding tissue was high in most cases. In direct comparison to FDG-PET, the SUVs of primary tumours (5/6) and axillary lymph node metastases (3/4) were lower in FLT-PET (SUV_FLT: 3.2 vs SUV_FDG: 4.7 in primary tumours and SUV_FLT: 2.9 vs SUV_FDG: 4.6 in lymph node metastases). Since FLT uptake in surrounding breast tissue was also lower, tumour contrast was comparable to that with FDG. It is of note that normal FLT uptake was very low in the mediastinum, resulting in a higher tumour-to-mediastinum ratio as compared to FDG (P=0.03). FLT-PET is suitable for the diagnosis of primary breast cancer and locoregional metastases. High image contrast may facilitate the detection of small foci, especially in the mediastinum.     

Comparison of 18F-Choline PET/CT and MRI functional parameters in prostate cancer

Annals of Nuclear Medicine - 18F-Choline (FCH) uptake parameters are strong indicators of aggressive disease in prostate cancer. Functional parameters derived by magnetic resonance imaging (MRI)...