Accuracy of MRI and <Superscript>18</Superscript>F-FDG PET/CT for Restaging After Preoperative Concurrent Chemoradiotherapy for Rectal Cancer

Background  

Performing a restaging work-up with magnetic resonance imaging (MRI) and ¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) can provide information about the effects that are related to preoperative concurrent chemoradiotherapy (CCRT). The purpose of the present study was to investigate the accuracy of MRI and ¹⁸F-FDG PET/CT for restaging after preoperative CCRT for rectal cancer.     

Clinical value of 18FDG PET/MRI in muscle-invasive,locally advanced,and metastatic bladder cancer

ObjectiveMetastatic bladder cancer is an aggressive disease that can often be difficult to diagnose and stage with conventional cross-sectional imaging. The primary objective of this study was to determine the clinical value of fluorine-18 2-fluoro-2-deoxy-D-glucose (¹⁸F-FDG) PET/MRI for surveillance and restaging of patients with muscle-invasive, locally advanced, and metastatic bladder cancer compared to conventional imaging methods.Materials and MethodsThis retrospective study enrolled patients with muscle-invasive, locally advanced and metastatic bladder cancer in a single institute evaluated with ¹⁸F-FDG PET/MRI. All patients also underwent conventional imaging with CT. Additional imaging may also have included ¹⁸F-FDG PET/CT (¹⁸F-FDG PET), or sodium fluoride (NaF) PET/CT in some patients. Images were reviewed by a diagnostic radiologist/nuclear medicine physician. Number of lesions and sites of disease were captured and compared between ¹⁸F-FDG PET/MRI and conventional imaging. Lesions were confirmed by sequential imaging or lesion biopsy. All patients were followed for survival.ResultsFifteen patients (4 for surveillance; 11 for restaging) underwent 34 ¹⁸F-FDG PET/MRI scans. Each patient received a corresponding conventional CT around the time of the ¹⁸F-FDG PET/MRI (median 6 days). The 15 patients (11 male; 4 female) had a median age of 61.5 years (range 37–73) and histologies of urothelial carcinoma (n = 13) and small-cell carcinoma of the bladder (n = 2) diagnosed as stage 4 (n = 13), stage 3 (n = 1), or stage 2 (n = 1). ¹⁸F-FDG PET/MRI detected 82 metastatic malignant lesions involving lymph nodes (n = 22), liver (n = 10), lung (n = 34), soft tissue (n = 12), adrenal glands (n = 1), prostate (n = 1), and bone (n = 2) with a resultant advantage of 36% for lesion visibility in comparison with CT. Serial imaging or biopsy confirmed these lesions as malignant.Conclusion¹⁸F-FDG PET/MRI can detect metastatic lesions which cannot be identified on conventional CT, and this can allow for better treatment planning and improved disease monitoring during therapy.     

Imaging of multiple myeloma: Current concepts

Medical imaging is of crucial importance for diagnosis and initial staging as well as for differentiation of multiple myeloma (MM) from other monoclonal plasma cell diseases. Conventional radiography represents the reference standard for diagnosis of MM due to its wide availability and low costs despite its known limitations such as low sensitivity, limited specificity and its inability to detect extraosseous lesions. Besides conventional radiography, newer cross-sectional imaging modalities such as whole-body low-dose computed tomography (CT), whole-body magnetic resonance imaging (MRI) and ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT are available for the diagnosis of osseous and extraosseous manifestations of MM. Whole-body low-dose CT is used increasingly, replacing conventional radiography at selected centers, due to its higher sensitivity for the detection of osseous lesions and its ability to diagnose extraosseous lesions. The highest sensitivity for both detection of bone marrow disease and extraosseous lesions can be achieved with whole-body MRI and ¹⁸F-FDG PET/CT. According to current evidence, MRI is the most sensitive method for initial staging while ¹⁸F-FDG PET/CT allows monitoring of treatment of MM. There is an evolving role for assessment of treatment response using newer MR imaging techniques. Future studies are needed to further define the exact role of the different imaging modalities for individual risk stratification and therapy monitoring.     

Comparison of Uptake Characteristics and Prognostic Value of <Superscript>201</Superscript>Tl and <Superscript>18</Superscript>F-FDG in Esophageal Cancer

Background Patients with esophageal cancer often undergo ²⁰¹Tl myocardial imaging for preoperative risk evaluation, thereby providing an excellent opportunity to assess tumor handling of ²⁰¹Tl. We thus compared the characteristics of ²⁰¹Tl and ¹⁸F-FDG uptake by esophageal cancer and further investigated their prognostic values. Methods The study included 100 newly diagnosed esophageal cancer patients who underwent preoperative ²⁰¹Tl SPECT and ¹⁸F-FDG PET exams. Tumor to mediastinal uptake (T/M) ratio and retention index (RI) of ²⁰¹Tl, tumor ¹⁸F-FDG pSUV, tumor size, location, and stage were assessed. Survival analysis was performed for disease-free survival using the Kaplan–Meier method. Cox proportional hazard models were used to determine independent risk factors. Results ²⁰¹Tl SPECT and ¹⁸F-FDG PET visualized the primary tumor in 85/100 (85.0%) and 91/100 (91.0%) patients, respectively (p = 0.03). There were close correlations between early and delayed ²⁰¹Tl T/M ratios (r = 0.83, p < 0.0001) and between T/M ratios and ¹⁸F-FDG pSUV (r = 0.56 and 0.57, respectively, both p < 0.0001). Both T/M ratios and ¹⁸F-FDG pSUV correlated significantly with tumor stage (ρ = 0.45, 0.40, and 0.59, respectively, all p < 0.0001). Survival analysis revealed tumor size, ²⁰¹Tl negative tumors, ¹⁸F-FDG negative tumors, delayed ²⁰¹Tl T/M ratio, RI, stage, and ¹⁸F-FDG pSUV to be significant univariate predictors for disease-free survival. Multivariate survival analysis showed stage (p = 0.02) to be a significant independent prognostic predictor. Conclusions In patients with esophageal cancer, assessment of tumor ²⁰¹Tl uptake, as with ¹⁸F-FDG, may provide potentially useful information regarding tumor characteristics. Presented in part at the 51st Annual Meeting of the Society of Nuclear Medicine, Philadelphia, PA, USA, June 19–23, 2004.     

<Superscript>99m</Superscript>Tc-HDP bone scintigraphy and <Superscript>18</Superscript>F-sodiumfluoride PET/CT in primary staging of patients with prostate cancer

Introduction/Aim

Correct staging of patients with prostate cancer is important for treatment planning and prognosis. Although bone scintigraphy with ^99mTc-phosphonates (BS) is generally advised for staging by guidelines in high risk prostate cancer, this imaging technique is hampered by a high rate of inconclusive results and moderate accuracy. Potentially better imaging techniques for detection of bone metastases such as ¹⁸F-sodiumfluoride PET/CT (NaF PET/CT) are therefore being evaluated. In this observational cohort study we evaluate the performance and clinical impact of both BS and NaF PET/CT in primary staging of patients with prostate cancer.

Methods

The first of two cohorts consisted of patients who received a BS while the second included patients who received a NaF PET/CT for primary staging of prostate cancer. For both cohorts the number of positive, negative and equivocal findings, calculated diagnostic performance of the imaging modality in terms of sensitivity and specificity, as well as the impact on clinical management were studied. The ranges of the diagnostic performance were calculated both assuming that equivocal findings were positive and assuming that they were negative for bone metastases. For the NaF PET/CT cohort the number of patients with signs of lymph node metastases on low dose CT were also recorded, including the impact of these findings on clinical management.

Results

One-hundred-and-four patients underwent NaF PET/CT, whereas 122 patients underwent BS. Sensitivities of 97–100 and 84–95% and specificities of 98–100 and 72–100% were found on a patient basis for detection of bone metastases with NaF PET/CT and BS, respectively. Equivocal findings warranted further diagnostic procedures in 2% of the patients in the NaF cohort and in 16% in the BS cohort. In addition NaF PET/CT demonstrated lymph node metastases in 50% of the included patients, of which 25% showed evidence of lymph node metastases only.

Conclusion

Our data indicate better diagnostic performance of NaF PET/CT compared to BS for detection of bone metastases in primary staging of prostate cancer patients. Less equivocal findings are encountered with NaF PET/CT. Moreover, NaF PET/CT has additional value over BS since lymph node metastases are encountered frequently.

     

The incremental value of magnetic resonance imaging for breast surgery planning

Purpose

The aim of this study was to evaluate the effect of breast magnetic resonance imaging (MRI) on preoperative or intraoperative surgical planning.

Methods

One hundred and sixty females with breast cancer were enrolled in the study. The contribution of MRI compared to MMG and USG, their histopathological concordance, and their impact on surgical treatment were evaluated prospectively.

Results

In 48 (30.0%) of the patients, MRI identified suspicious lesions that were not detected by MMG and USG. The diagnosis by MRI was accurate in 17 (10.6%) of them, while in remaining 31 patients (19.4%) the additional lesions found by MRI and interpreted as malignant were found not to be malignant. The pathological accordance of MRI and MMG compared with USG were 69.3 and 70.0%, respectively, whereas individually, MMG and USG were in accordance with the pathological examination in 52.9 and 67.9% of the cases, respectively.

Conclusions

Assessment of the tumor size, multifocality, multicentricity, and presence of ductal carcinoma in situ by MRI may lead to misinterpretations in the majority of patients. The surgical approach should not be changed based solely on MRI findings. An accurately interpreted MMG combined with USG may be sufficient in most cases.     

Funktionelle Bildgebung beim Harnblasenkarzinom

Computed tomography (CT) represents the current standard imaging modality in muscle invasive bladder cancer; however, local tumor and lymph node staging is often impaired. Magnetic resonance imaging (MRI) with diffusion-weighted sequences, determination of apparent diffusion coefficient (ADC) values or utilization of supraparamagnetic iron nanoparticles potentially exhibits advantages in the assessment of local tumor and lymph node involvement and therefore might play a role in the staging of bladder tumor in the future. Likewise, positron emission tomography (PET) with the currently used tracers ¹⁸F fluorodeoxyglucose (¹⁸F-FDG), ¹¹C-choline and ¹¹C-acetate is being investigated in bladder cancer patients, mostly in combination with diagnostic CT. Although promising results could be obtained for PET/CT investigations to some extent, the true value cannot be determined at present.     

Relationship Between <Superscript>18</Superscript>F-fluorodeoxyglucose Accumulation and the <Emphasis Type="Italic">BRAF</Emphasis><Superscript>V600E</Superscript> Mutation in Papillary Thyroid Cancer

Background

To determine whether ¹⁸F-fluoro-2-deoxyglucose (¹⁸F-FDG)-PET/CT is useful for predicting the BRAF ^V600E mutation status of a primary papillary thyroid carcinoma (PTC).

Methods

A retrospective analysis was performed in 108 patients who underwent ¹⁸F-FDG positron emission tomography–computed tomography (PET/CT) for staging before thyroidectomy and BRAF analysis in biopsy-confirmed PTC. The maximum standardized uptake value (SUV_max) of the primary tumor was calculated according to FDG accumulation. Univariate and multivariate analyses were performed to assess the association between the SUV_max and clinicopathological variables.

Results

The BRAF ^V600E mutation was detected in 71 of 108 (65.7%) patients. In all subjects, the tumor size and BRAF ^V600E mutation were independently related to the SUV_max according to multivariate analyses (P = 0.002 and 0.007, respectively). The SUV_max was significantly higher in tumors with the BRAF ^V600E mutation than in tumors with wild-type BRAF (10.24 ± 11.89 versus 4.02 ± 3.86; P = 0.007). In the tumor size >1 cm subgroup, the BRAF ^V600E mutation was the only factor significantly associated with the SUV_max (P = 0.016). A SUV_max cutoff level of 4.9 was determined to be significant for predicting the BRAF ^V600E mutation status (sensitivity 77.4%, specificity 100.0%, area under the curve 0.929; P < 0.0001) according to ROC curve analysis.

Conclusions

The BRAF ^V600E mutation is independently associated with high ¹⁸F-FDG uptake in PTC, especially in those with a tumor size >1 cm.

     

Utility of ¹⁸F-FDG PET/CT in identifying penile squamous cell carcinoma metastatic lymph nodes

ObjectivesDue to the significant potential morbidity of inguinal and pelvic lymphadenectomy, the search for an imaging modality that can accurately identify penile squamous cell carcinoma (SCCA) lymphatic metastases continues. Initial ¹⁸F-FDG PET/CT studies have reported 80% sensitivity and 100% specificity in the detection of inguinal and obturator lymph node metastasis. We review a single institutional experience of ¹⁸F-FDG PET/CT imaging of SCCA of the penis to assess for accuracy and potential impact on clinical management.MethodsThree patients diagnosed with penile SCCA at a single institution underwent staging ¹⁸F-FDG PET/CT and went on to subsequent inguinal lymph node dissection. The ¹⁸F-FDG PET machine was a Philips Gemini Time-of-Flight PET with LYSO crystals with 4.7 mm spatial resolution. The CT was a 16-slice helical CT with 5 mm slice widths. ¹⁸F-FDG PET/CT findings were compared with the histologic findings of these procedures. Decision to proceed with lymphadenectomy was based on clinical judgment of a single urologist and all fused ¹⁸F-FDG PET/CT imaging was assessed by a single experienced radiologist.ResultsNo patient received chemotherapy or radiation before the ¹⁸F-FDG PET/CT or surgery. The first patient was obese (BMI > 30), clinically node negative, and the ¹⁸F-FDG PET/CT showed inflammation. Histologic examination showed a positive 2 cm right inguinal metastatic node. The second patient's ¹⁸F-FDG PET/CT showed a suspicious 1 cm left inguinal node. Histologically, the suspicious lymph node was positive for SCCA as was a second positive 2 cm lymph node not identified on preoperative ¹⁸F-FDG PET/CT. Clinical exam of this patient was negative. The third patient was ¹⁸F-FDG PET/CT and clinically negative but subsequently developed a palpable lymph node approximately 1 month later, which was suspicious on repeat ¹⁸F-FDG PET/CT and positive for SCCA on histological examination.Conclusions¹⁸F-FDG PET/CT has shown initial promise in the staging of penile SCCA. However, our review shows that false negative studies occur at alarmingly high rates, and ¹⁸F-FDG PET/CT is poor in detection of micro-metastasis. Thus, close follow-up in these patients is imperative.     

Prognostic Value of Metabolic Tumor Volume Measured by <Superscript>18</Superscript>F-Fluorodeoxyglucose Positron Emission Tomography in Patients with Esophageal Carcinoma

Purpose  

The aim of this study was to evaluate the prognostic value of metabolic tumor volume (MTV) measured by ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) in patients with esophageal carcinoma.     

Characteristics of Primary Papillary Thyroid Carcinoma with False-Negative Findings on Initial 18F-FDG PET/CT

Background

We often observe that uptake of tracer is not detected in the primary cancer focus in patients with histologically proven papillary thyroid carcinoma (PTC) on preoperative ¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸F-FDG PET/CT). Therefore, we analyzed the clinical and pathologic variables affecting false-negative findings in primary tumors on preoperative ¹⁸F-FDG PET/CT.

Methods

We retrospectively reviewed the medical records of 115 consecutive patients who underwent ¹⁸F-FDG PET/CT for initial evaluation and were diagnosed with PTC by postoperative permanent biopsy. The clinical and pathologic characteristics that influence the ¹⁸F-FDG PET/CT findings in these patients were analyzed with respect to the following variables: age, gender, tumor size, multifocality of the primary tumor, perithyroidal invasion, lymphovascular or capsular invasion, and central lymph node metastasis-based final pathology.

Results

Twenty-six (22.6%) patients had false-negative ¹⁸F-FDG PET/CT findings. In patients with negative ¹⁸F-FDG PET/CT findings, tumor size, and perithyroidal and lymphovascular invasion were significantly less than in patients with positive ¹⁸F-FDG PET/CT findings. Tumors >1 cm in size were correlated with ¹⁸F-FDG PET/CT positivity. On multivariate analysis, perithyroidal invasion (P = 0.026, odds ratio = 7.714) and lymphovascular invasion (P = 0.036, odds ratio = 3.500) were independent factors for ¹⁸F-FDG PET/CT positivity. However, there were no significant differences between ¹⁸F-FDG PET/CT positivity and age, gender, capsular invasion, and central lymph node metastasis based on final pathology.

Conclusions

Tumor size and perithyroidal and lymphovascular invasion of papillary carcinoma can influence ¹⁸F-FDG PET/CT findings. Absence of perithyroidal and lymphovascular invasion were independent variables for false-negative findings on initial ¹⁸F-FDG PET/CT in patients with PTC.     

Preoperative lymph-node staging of invasive urothelial bladder cancer with 18F-fluorodeoxyglucose positron emission tomography/computed axial tomography and magnetic resonance imaging: correlation with histopathology

OBJECTIVE: The treatment and prognosis of bladder cancer are based on the depth of primary tumour invasion and the presence of metastases. A highly accurate preoperative tumour, node, metastasis (TNM) staging is critical to proper patient management and treatment. This study retrospectively investigated the value of 1?F-fluorodeoxyglucose (FDG) positron emission tomography/computed axial tomography (1?F-FDG PET/CT) and magnetic resonance imaging (MRI) for preoperative N staging of bladder cancer. Material and methods. From June 2006 to January 2008, 48 consecutive patients diagnosed with bladder cancer were referred to preoperative staging including MRI and 1?F-FDG PET/CT. Eighteen out of 48 patients underwent radical cystoprostatectomy including removal of lymph nodes for histology, and were included in the study. Values of 1?F-FDG PET/CT and MRI for regional N staging were compared to histopathology findings, the gold standard. Results. 1?F-FDG PET/CT and MRI were performed in 18 patients. The specificities for detection of lymph-node metastases for MRI and 1?F-FDG PET/CT were 80% (n = 15) and 93.33% (n = 15), respectively. The negative predictive values were 80% (n = 15) and 87.5% (n = 16) for MRI and 1?F-FDG PET/CT, respectively. The differences in specificity and negative predictive values were not statistically significant. Conclusions. No significant statistical difference between 1?F-FDG PET/CT and MRI for preoperative N staging of urothelial bladder cancer was found in the study. However, the trend of the data indicates an advantage of 1?F-FDG PET/CT over MRI. Larger prospective studies are needed to elucidate the role of 1?F-FDG PET/CT in N staging of bladder cancer.     

The Added Diagnostic Value of <Superscript>18</Superscript>F-Fluorodihydroxyphenylalanine PET/CT in the Preoperative Work-Up of Small Bowel Neuroendocrine Tumors

Background

The precise localization of the primary tumor and/or the identification of multiple primary tumors improves the preoperative work-up in patients with small bowel (SB) neuroendocrine tumor (NET). The present study assesses the diagnostic value of ¹⁸F-fluorodihydroxyphenylalanine (¹⁸F-FDOPA) positron emission tomography/computed tomography (PET/CT) during the preoperative wok-up of SB NETs.

Methods

Between January 2010 and June 2017, all consecutive patients with SB NETs undergoing preoperative ¹⁸F-FDOPA PET/CT and successive resection were analyzed. Preoperative work-up included computed tomography (CT), somatostatin receptor scintigraphy (SRS), and ¹⁸F-FDOPA PET/CT. Sensitivity and accuracy ratio for primary and multiple tumor detection were compared with data from surgery and pathology.

Results

There were 17 consecutive patients with SB NETs undergoing surgery. Nine patients (53%) had multiple tumors, 15 (88%) metastatic lymph nodes, 3 (18%) peritoneal carcinomatosis, and 9 patients (53%) liver metastases. A total of 70 SB NETs were found by pathology. Surgery identified the primary in 17/17 (100%) patients and recognized seven of 9 patients (78%) with multiple synchronous SB. Preoperatively, ¹⁸F-FDOPA PET/CT displayed a statistically significant higher sensitivity for primary tumor localization (100 vs. 23.5 vs. 29.5%) and multiple tumor detection (78 vs. 22 vs. 11%) over SRS and CT. Compared with pathology, ¹⁸F-FDOPA PET/CT displayed the highest accuracy ratio for number of tumor detected over CT and SRS (2.0?±?2.2 vs. 0.4?±?0.7 vs. 0.6?±?1.5, p?=?0.0003).

Conclusion

¹⁸F-FDOPA PET/CT significantly increased the sensitivity and accuracy for primary and multiple SB NET identification. ¹⁸F-FDOPA PET/CT should be included systematically in the preoperative work-up of SB NET.

     

18F-FDG PET/CT在胆道系统恶性肿瘤中的应用

目的探讨~(18)F-FDG PET/CT诊断胆道系统恶性肿瘤的价值。方法回顾性分析34例临床疑似胆道恶性肿瘤患者的PET/CT影像资料,均获得术后病理结果,其中12例经手术切除淋巴结或淋巴结穿刺活检对18枚淋巴结获得病理诊断;与病理结果对照,计算PET/CT对胆道恶性病变原发灶、淋巴结转移的灵敏度、特异度、阳性预测值、阴性预测值及准确率。结果 34例中,31例为恶性病变,3例为良性病变。PET/CT诊断胆道恶性肿瘤原发灶的灵敏度100%(31/31),特异度66.67%(2/3),阳性预测值96.88%(31/32),阴性预测值100%(2/2),准确率97.06%(33/34)。胆道恶性病变原发灶最大标准摄取值(SUV_(max))为8.42±4.27;3例胆道良性疾病SUV_(max)分别为12.90、2.00及1.90。共18枚淋巴结获得病理结果,包括转移性淋巴结13枚,良性增生5枚。PET/CT诊断淋巴结转移的灵敏度76.92%(10/13),特异度60.00%(3/5),阳性预测值83.33%(10/12),阴性预测值50.00%(3/6),准确率72.22%(13/18)。结论 PET/CT对胆道系统恶性肿瘤的诊断具有重要价值。     

核医学影像技术在淋巴瘤诊疗中的应用

近年来,功能性显像技术在淋巴瘤诊疗中逐渐占据重要地位。用于淋巴瘤诊疗的核医学影像技术主要包括单光子发射型断层扫描技术（SPECT）、正电子发射型断层显像（PET）、正电子发射型断层/计算机体层摄影术（PET/CT）。67Ga-枸橼酸较早用于诊断淋巴瘤的功能性显像,后逐渐被18F-FDG取代。PET/CT的应用实现了功能影像与解剖影像有机结合及优势互补,对淋巴瘤的定位、定性及分期更准确,在淋巴瘤的诊疗方面显示出重要的临床应用价值。本文对18F-FDG PET及PET/CT在淋巴瘤诊疗方面的应用现状进行综述。     

18F-FDG Uptake at Initial Staging of the Adrenocortical Cancers: A Diagnostic Tool but Not of Prognostic Value

Background

Adrenocortical carcinoma (ACC) is a rare cancer for which little level evidence exists to guide management. ¹⁸F-FDG PET (¹⁸F-fluorodeoxyglucose positron emission tomography) is an increasingly used diagnostic tool in patients with suspicious or indeterminate adrenal tumors. In some other solid tumors, ¹⁸F-FDG PET may offer prognostic information that can guide optimal patient treatment. The aim of the present study was to evaluate whether preoperative ¹⁸F-FDG PET based on SUVs assessments has a prognostic value in ACC patients.

Methods

A retrospective analysis was performed in patients who underwent ¹⁸F-FDG PET/CT for the evaluation of ACC. Inclusion criteria were an unequivocal diagnosis of ACC; all data from primary diagnosis available; ¹⁸F-FDG PET/CT performed prior to surgery or other treatment of the primary tumor; a minimum of 6-months follow-up for surviving patients. All ¹⁸F-FDG PET/CT procedures were reinterpreted in a blind fashion.

Results

Thirty-seven patients (23 without metastasis [M0], 14 with metastasis [M1]) fulfilled the study criteria. Median uptake values were tumor standardized uptake values (SUV)_max = 11 (range: 3–56) and a tumor/liver SUV_max ratio = 4.2 (range: 1.3–15). Median follow-up was 20 months. Although classic risk factors (tumoral stage, Weiss score) were associated with poor outcome, there was no correlation between primary tumor FDG uptake with overall survival (OS) and disease free survival (DFS) in M0 patients and with overall survival in M1 patients. ¹⁸F-FDG uptake correlated inconsistently with sinister histological features, such as atypical mitoses or necrosis.

Conclusions

At initial staging, primary tumor FDG uptake in ACC patients does not correlate with OS and DFS at 2 years. Patient prognosis and treatment strategy should not be based on uptake values.     

Imaging Prostate Cancer: An Update on Positron Emission Tomography and Magnetic Resonance Imaging

Prostate cancer is a common cancer in men and continues to be a major health problem. Imaging plays an essential role in the clinical management of patients. An important goal for prostate cancer imaging is more accurate disease characterization through the synthesis of anatomic, functional, and molecular imaging information. Developments in imaging technologies, specifically magnetic resonance imaging (MRI) and positron emission tomography (PET)/computed tomography (CT), have improved the detection rate of prostate cancer. MRI has improved lesion detection and local staging. Furthermore, MRI allows functional assessment with techniques such as diffusion-weighted MRI, MR spectroscopy, and dynamic contrast-enhanced MRI. The most common PET radiotracer, ¹⁸F-fluorodeoxyglucose, is not very useful in prostate cancer. However, in recent years other PET tracers have improved the accuracy of PET/CT imaging of prostate cancer. Among these, choline (labeled with ¹⁸F or ¹¹C), ¹¹C-acetate, and ¹⁸F-fluoride have demonstrated promising results, and other new radiopharmaceuticals are currently under evaluation in preclinical and clinical studies.     

18F-FDGPET/CT在非小细胞肺癌早期化疗疗效评价中的应用

18F-FDG PET/CT是一种从细胞分子水平反映肿瘤组织生化和代谢变化的功能显像方法,其监测肿瘤治疗疗效的原理是基于肿瘤细胞在化疗后对葡萄糖代谢的变化。近年来,越来越多的研究致力于18 F-FDG PET/CT在评价非小细胞肺癌化疗疗效方面的作用。本文就18F-FDG PET/CT在非小细胞肺癌早期化疗疗效评价中的应用价值进行综述。     

PET/CT in the management of differentiated thyroid cancer

The standard treatment of differentiated thyroid cancer (DTC) consists of surgery followed by iodine-131 (¹³¹I) administration. Although the majority of DTC has a very good prognosis, more aggressive histologic subtypes convey a worse prognosis. Follow-up consists of periodically measurements of serum thyroglobulin, thyroglobulin antibodies and neck ultrasound and ¹²³I/¹³¹I whole-body scan. However, undifferentiated thyroid tumors have a lower avidity for radioiodine and the ability of DTC to concentrate ¹³¹I may be lost in metastatic disease. Positron emission tomography (PET)/computed tomography (CT) has been introduced in the evaluation of patients with thyroid tumors and the 2-[18F]-fluoro-2-deoxyd-glucose (¹⁸F-FDG) has been largely validated as marker of cell's metabolism. According to the 2015 American Thyroid Association guidelines, ¹⁸F-FDG PET/CT is recommended in the follow-up of high-risk patients with elevated serum thyroglobulin and negative ¹³¹I imaging, in the assessment of metastatic patients, for lesion detection and risk stratification and in predicting the response to therapy. It should be considered that well-differentiated iodine avid lesions could not concentrate ¹⁸F-FDG, and a reciprocal pattern of iodine and ¹⁸F-FDG uptake has been observed. Beyond ¹⁸F-FDG, other tracers are available for PET imaging of thyroid tumors, such as Iodine-124 (¹²⁴I), ¹⁸F-tetrafluoroborate and Gallium-68 prostate-specific membrane antigen. Moreover, the recent introduction of PET/MRI, offers now several opportunities in the field of patients with DTC. This review summarizes the evidences on the role of PET/CT in management of patients with DTC, focusing on potential applications and on elucidating some still debating points.     

Utility of 18F-FDG PET/CT for Detecting Neck Metastasis in Patients with Salivary Gland Carcinomas: Preoperative Planning for Necessity and Extent of Neck Dissection

Background:

The precise diagnosis of cervical lymph node metastasis (CLNM) of salivary gland cancer is important to determine the surgical extent and adjuvant therapy. This study assessed the clinical utility of ¹⁸F-FDG PET in identifying CLNM in such patients.

Methods:

Fifty-four patients with intermediate or high-grade salivary gland cancer were preoperatively evaluated with ¹⁸F-FDG PET/CT and CT/MRI. Histopathologic analysis of neck dissection tissues was used as the gold standard for assessing imaging techniques. Tumor and nodal maximum standardized uptake values (SUVmax) were measured for each patient. Univariate and multivariate analyses were used to identify CLNM predictive factors.

Results:

Of the 54 patients, 24 patients (44 %) had CLNM. On a per-patient basis, the sensitivity and specificity of ¹⁸F-FDG PET/CT and CT/MRI were not significantly different (92 vs. 83 %, P = 0.625 and 93 vs. 97 %, P = 1.000, respectively). On a per-level basis, ¹⁸F-FDG PET/CT was significantly more sensitive and accurate than CT/MRI in the ipsilateral neck (96 vs. 54 %, P < 0.001 and 92 vs. 83 %, P < 0.001, respectively). The mean nodal SUVmax values of patients with and without nodal metastasis were 4.9 and 2.1, respectively (P = 0.008). Histologic grade was a significant predictor of CLNM (P = 0.014, odds ratio 14.46, 95 % confidence interval 1.73–120.79).

Conclusions:

¹⁸F-FDG PET/CT imaging and histologic grade are useful for detecting CLNM in patients with salivary gland carcinoma. This finding may guide preoperative planning for the necessity and extent of neck dissection in these patients.