Detection rate of fluorine‐18‐fluorodeoxyglucose positron emission tomography in patients with marginal zone lymphoma of MALT type: a meta‐analysis

The aim of this article is to meta‐analyse published data about the detection rate (DR) of fluorine‐18‐fluorodeoxyglucose (¹⁸F‐FDG) positron emission tomography (PET) and PET/computed tomography (CT) in the evaluation of patients with marginal zone lymphoma of the mucosa‐associated lymphoid tissue (MALT). A comprehensive literature search of studies published through February 2014 was performed. Pooled DR of ¹⁸F‐FDG PET or PET/CT including 95% confidence intervals (95% CI) was calculated on a per‐patient‐based analysis. Twenty studies including 376 patients with MALT lymphoma were selected. The pooled DR of ¹⁸F‐FDG PET or PET/CT was 71% (95% CI: 61–80%). A significant difference between the DR of PET/CT (69%; 95% CI: 61–80%) and that of PET alone (73%; 95% CI: 60–84%) was not demonstrated. A better DR of ¹⁸F‐FDG PET or PET/CT in bronchial (94%; 95% CI: 85–99%) and head‐and‐neck (90%; 95% CI: 78–98%) MALT lymphomas compared with gastric (62%; 95% CI: 46–77%) and ocular (49%; 95% CI: 36–63%) MALT lymphomas was found. This meta‐analysis demonstrates that MALT lymphoma is an ¹⁸F‐FDG‐avid tumour in most of the cases, suggesting a potential clinical role of ¹⁸F‐FDG PET or PET/CT in the initial evaluation of these patients. In particular, the DR of ¹⁸F‐FDG PET or PET/CT is related to the primary site of the MALT lymphoma. Copyright © 2014 John Wiley & Sons, Ltd.     

Standardized uptake value based evaluation of lymphoma by FDG and FLT PET/CT

Although ¹⁸F‐FDG PET/CT imaging is the conventional method for evaluating lymphoma, PET/CT imaging with radiopharmaceuticals other than FDG is being investigated. We evaluated the utility of different standardized uptake value (SUV) measurements in ¹⁸F‐FLT PET/CT scans compared with PET/CT scans performed with FDG. Two scans, each using one of the radiopharmaceuticals, were performed on each of 114 patients with histologically proven lymphoma. Maximum and mean SUV (SUVmax) and (SUVmean) of all visualized lesions, with backgrounds of mediastinal blood pool, liver, spleen and vertebra were calculated. The ratios of the SUVs of the lesions to those of each reference region were statistically analyzed. Using receiver operating characteristic curves, we analyzed the differences in uptake of the two agents in aggressive and indolent B‐cell non‐Hodgkin lymphoma. We found that the SUVmax measurements of FDG were significantly different between aggressive and indolent B‐cell non‐Hodgkin lymphoma. The receiver operating characteristic curve of SUVmax of tumour/liver for FDG studies resulted in the most area under the curve. The SUVmax of the tumour/mediastinum ratio for FLT studies resulted in the most area under the curve (0.781). There was no significant correlation between FDG and FLT uptake in most types of lymphoma we studied. Further studies of the characteristics of ¹⁸F‐FLT should employ the tumour/mediastinum SUVmax ratio for accurate uptake measurement. Copyright © 2013 John Wiley & Sons, Ltd.     

Role of fluorine‐18‐fluorodeoxyglucose positron emission tomography/computed tomography in evaluating breast mucosa‐associated lymphoid tissue lymphoma: A case series

Mucosa‐associated lymphatic tissue (MALT) lymphoma of the breast is an extremely rare disease; its pathogenesis is not clear because of the rarity of disease, and the best diagnostic method has yet to be established. The metabolic behavior of this lymphoma is not still clear because only a few case reports are present in literature describing the possible role of fluorine‐18‐fluorodeoxyglucose positron emission tomography/computed tomography (18F‐FDG PET/CT) in this field. This report presents 4 cases of women with histologically proven breast MALT lymphoma who underwent 7 18F‐FDG PET/CT throughout the course of disease. All patients underwent staging PET/CT showing in all cases an FDG avid lesion corresponding to breast lymphoma; 3 patients underwent 18F‐FDG PET/CT also after chemotherapy. Our results suggest that breast MALT lymphomas are 18F‐FDG‐avid lymphomas. Positron emission tomography/computed tomography showed heterogeneous but high FDG uptake (mean maximum standardized uptake value 7.9), suggesting that it could be part of diagnostic workup and restaging process.     

Prognostic role of baseline 18F‐FDG PET/CT parameters in MALT lymphoma

Mucosa‐associated lymphoid tissue (MALT) lymphoma is an indolent lymphoma with good prognosis and variable fluorine‐18 fluorodeoxyglucose (¹⁸F‐FDG) avidity. Many possible prognostic factors have been investigated with controversial results, but the possible prognostic role of ¹⁸F‐FDG positron emission tomography/computed tomography (PET/CT) remains unclear. Our aim was to evaluate the prognostic impact of qualitative and semiquantitative baseline PET/CT parameters on outcome of MALT lymphoma. We retrospectively enrolled 161 patients with histologically confirmed MALT lymphoma who underwent ¹⁸F‐FDG PET/CT before any treatment. PET images were qualitatively and semiquantitatively analyzed by measuring the maximum standardized uptake value body weight (SUVbw), lean body mass (SUVlbm), body surface area (SUVbsa), metabolic tumor volume (MTV), and total lesion glycolysis (TLG). The Kaplan‐Meier method was used to estimate the progression‐free survival (PFS) and overall survival (OS) times. Cox regression models were performed to determine the relation between PET/CT features and OS and PFS. Ninety‐eight patients had positive ¹⁸F‐FDG PET/CT showing ¹⁸F‐FDG uptake (mean SUVbw, 10.1; SUVlbm, 7.2; SUVbsa, 2.7; MTV, 88.8; and TLG, 526); the remaining 63 were not ¹⁸F‐FDG avid. ¹⁸F‐FDG avidity was significantly correlated with tumor size and Ki‐67 score. Relapse/progression of disease occurred in 47 patients with an average time of 40.2 months; death occurred in 12 patients with an average of 59 months. At a median follow‐up of 62 months, median PFS and OS were 52 and 62 months, respectively. Advanced tumor stage and extragastric site were demonstrated to be independent prognostic factors for PFS, while only tumor stage for OS. Instead, PET/CT parameters were not related to survival, despite positive correlation at univariate analysis between MTV and TLG with PFS and positive PET/CT with PFS and OS. In conclusion, a 61% rate of PET avidity in biopsy‐confirmed MALT lymphoma was found, and it was correlated with tumor size and Ki‐67 score. Only tumor stage and localization were independently correlated with PFS and OS.     

COVID-19 vaccine related hypermetabolic lymph nodes on PET/CT: Implications of inflammatory findings in cancer imaging

We observed several patients presenting 2-[¹⁸F]FDG uptake in the reactive axillary lymph node at PET/CT imaging, ipsilateral to the site of the COVID-19 vaccine injection. Analog finding was documented at [¹⁸F]Choline PET/CT. The aim of our study was to describe this source of false positive cases. All patients examined by PET/CT were included in the study. Data concerning patient anamnesis, laterality, and time interval from recent COVID-19 vaccination were recorded. SUVmax was measured in all lymph nodes expressing tracer uptake after vaccination. Among 712 PET/CT scans with 2-[¹⁸F]FDG, 104 were submitted to vaccination; 89/104 patients (85%) presented axillary and/or deltoid tracer uptake, related to recent COVID-19 vaccine administration (median from injection: 11 days). The mean SUVmax of these findings was 2.1 (range 1.6–3.3). Among 89 patients with false positive axillary uptake, 36 subjects had received chemotherapy due to lymph node metastases from somatic cancer or lymphomas, prior to the scan: 6/36 patients with lymph node metastases showed no response to therapy or progression disease. The mean SUVmax value of lymph nodal localizations of somatic cancers/lymphomas after chemotherapy was 7.8. Only 1/31 prostate cancer patients examined by [¹⁸F]Choline PET/CT showed post-vaccine axillary lymph node uptake. These findings were not recorded at PET/CT scans with [¹⁸F]-6-FDOPA, [⁶⁸Ga]Ga-DOTATOC, and [¹⁸F]-fluoride. Following COVID-19 mass vaccination, a significant percentage of patients examined by 2-[¹⁸F]FDG PET/CT presents axillary, reactive lymph node uptake. Anamnesis, low-dose CT, and ultrasonography facilitated correct diagnosis. Semi-quantitative assessment supported the visual analysis of PET/CT data; SUVmax values of metastatic lymph nodes were considerably higher than post-vaccine lymph nodes. [¹⁸F]Choline uptake in reactive lymph node after vaccination was confirmed. After the COVID-19 pandemic, nuclear physicians need to take these potential false positive cases into account in daily clinical practice.     

Imaging characteristics of extrapulmonary tuberculosis lesions on dual time point imaging (DTPI) of FDG PET/CT

Introduction: This study aimed to evaluate the diagnostic value of dual time point imaging (DTPI) of 18F‐fluorodeoxyglucose (FDG) positron emission tomography/CT (PET/CT) for detecting the infective lesions in patients with extrapulmonary tuberculosis (EPTB). Methods: Eleven patients were consecutively recruited and evaluated. After the intravenous injection of 369 ± 153 MBq of FDG, all patients underwent FDG PET/CT imaging at two different time points: early scan at 57 ± 23 min and delayed scan at 136 ± 42 min. The maximum standardized uptake values (SUVmax) were recorded for both time points (early scan: SUVmax1 and delayed scan: SUVmax2). Results: In total, 30 lesions were detected. The SUVmax2 in 22 of the lesions in confirmed EPTB patients were significantly higher than the SUVmax1 (7.9 ± 3.2 vs. 6.8 ± 2.5; P = 0.001). The SUVmax for another eight non‐EPTB lesions also showed a significant increasing pattern of change (6.2 ± 2.6 vs. 6.5 ± 2.8; P = 0.044). However, there was insignificant difference between the mean percentage difference of SUVmax (%ΔSUVmax) of EPTB and non‐EPTB lesions (P = 0.06). Conclusion: Our study demonstrates that early whole body PET/CT imaging may be sufficient for the detection of the EPTB lesions and DTPI of PET/CT may also not be a useful technique in differentiating between EPTB and non‐EPTB lesions. However, our findings are based on a limited number of patients, and therefore, further investigations in larger series of patients are warranted.     

[18F] FDG PET in Gastric Non-Hodgkin's Lymphoma

The possibility of using [¹⁸F] FDG PET for assessment of tumor extension in primary gastric non-Hodgkin's lymphoma (NHL) was studied in 8 patients (6 high-grade and 2 Iow-grade, one of the MALT type) and in a control group of 7 patients (5 patients with NHL without clinical signs of gastric involvement, 1 patient with NHL and benign gastric ulcer and 1 patient with adenocarcinoma of the stomach). All patients with gastric NHL and the two with benign gastric ulcer and adenocarcinoma, respectively, underwent endoscopy including multiple biopsies for histopathological diagnosis. All patients with high-grade and one of the two with low-grade NHL and the patient with adenocarcinoma displayed high gastric uptake of [¹⁸F] FDG corresponding to the pathological findings at endoscopy and/or CT. No pathological tracer uptake was seen in the patient with low-grade gastric NHL of the MALT type. In 6/8 patients with gastric NHL, [¹⁸F] FDG PET demonstrated larger tumor extension in the stomach than was found at endoscopy, and there was high tracer uptake in the stomach in two patients who were evaluated as normal on CT. [¹⁸F] FDG PET correctly excluded gastric NHL in the patient with a benign gastric ulcer and in the patients with NHL without clinical signs of gastric involvement. Although the experience is as yet limited, [¹⁸F] FDG PET affords a novel possibility for evaluation of gastric NHL and would seem valuable as a complement to endoscopy and CT in selected patients, where the technique can yield additional information decisive for the choice of therapy.     

18F-FDG PET/CT or PET Role in MALT Lymphoma: An Open Issue not Yet Solved—A Critical Review

Mucosa-associated lymphoid tissue (MALT) lymphoma involves the mucosa-associated lymphoid tissue potentially arising from any mucosal site, with the stomach as the most common site of involvement. MALT lymphoma is not usually an aggressive disease with a good prognosis except for selected cases. Fluorine-18 (¹⁸F) fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) is a noninvasive imaging tool used for staging, restaging, and evaluation of the treatment response in non-Hodgkin and Hodgkin lymphoma. However, its effective role in MALT lymphoma is not yet clear. The open question is whether these lymphomas are ¹⁸F-FDG avid or not, with conflicting results reported in the literature. Consequently, the possible clinical role of ¹⁸F-FDG PET/CT for staging and restaging purposes is under debate. The aim of the present review was to analyze the reported data about the role of ¹⁸F-FDG PET or PET/CT in patients with MALT lymphoma. We performed a comprehensive computer literature search of the Scopus, Cochrane, PubMed/MEDLINE, and Embase databases, including articles reported up to August 2019. We included 32 studies that had analyzed ¹⁸F-FDG PET or PET/CT for patients with MALT lymphoma. We analyzed the metabolic behavior of MALT lymphoma using ¹⁸F-FDG PET and the effect of the PET findings in the staging, treatment response evaluation, and prognosis.     

The prevalence and clinical significance of 18F–2‐fluoro‐2‐deoxy‐D‐glucose (FDG) uptake in the thyroid gland on PET or PET‐CT in patients with lymphoma

F¹⁸–2‐fluoro‐2‐deoxy‐D‐glucose (FDG) positron emission tomography (PET) has become a well established tool in staging and assessing therapy response in lymphoma. Incidental thyroid uptake on PET is not uncommon and can pose a diagnostic and management challenge. We retrospectively evaluate the prevalence and clinical significance of incidental FDG uptake in the thyroid gland in patients with lymphoma. 1868 lymphoma patients underwent PET and PET‐CT between August 2002 and August 2008. 52 patients (2.8%) demonstrated FDG thyroid uptake (M = 17, F = 35; mean age 63 yr). Thyroid uptake was determined as focal or diffuse, maximum standardized uptake values (SUVmax) recorded as well as SUV max ratio compared to background mediastinum activity (SUVR). Corresponding CT findings on PET‐CT were evaluated independently. Results were correlated with clinical, histopathological and imaging follow‐up. 30 (1.6%) patients had focal thyroid uptake. 16 (53%) had histological confirmation either by surgery (n = 7) or FNA under USS (n = 9). The final diagnosis was benign in 12/30 patients and malignant in 9/30. The malignancy risk for focal thyroid uptake was 30%. Five patients had intercurrent thyroid cancer (four papillary, one microinvasive follicular) and four had lymphomatous involvement. There was no significant difference between the mean sizes of benign (23.7 mm, range 12–34) and malignant nodules (23.6 mm, range 8–48). The mean SUVmax of malignant and benign nodules was 4.4 (range 1.8–10.1) and 3.2 (range 1.8–6.9) respectively with no statistically significant difference. 22 (1.2%) patients had diffuse FDG uptake in thyroid and benign aetiology was found in all with adequate follow‐up (15/22). Focal FDG thyroid uptake on PET or PET‐CT in lymphoma patients warrants further investigations. The malignancy risk is 30% either due to intercurrent thyroid cancer or lymphomatous involvement. SUVmax, SUVR and CT attenuation characteristics are not helpful in distinguishing between benign and malignant aetiologies. Diffuse thyroid uptake has a benign aetiology. Copyright © 2010 John Wiley & Sons, Ltd.     

Prognostic significance of metabolic tumor burden by positron emission tomography/computed tomography in patients with relapsed/refractory diffuse large B‐cell lymphoma

The aim of the present study was to investigate the feasibility of measuring metabolic tumor burden using [F‐18] fluorodeoxyglucose (¹⁸F‐FDG) positron emission tomography/computed tomography (PET/CT) in patients with relapsed or refractory diffuse large B‐cell lymphoma (DLBCL) treated with bendamustine–rituximab. Because the standardized uptake value is a critical parameter of tumor characterization, we carried out a phantom study of ¹⁸F‐FDG PET/CT to ensure quality control for 28 machines in the 24 institutions (Japan, 17 institutions; Korea, 7 institutions) participating in our clinical study. Fifty‐five patients with relapsed or refractory DLBCL were enrolled. The ¹⁸F‐FDG PET/CT was acquired before treatment, after two cycles, and after the last treatment cycle. Treatment response was assessed after two cycles and after the last cycle using the Lugano classification. Using this classification, remission was complete in 15 patients (27%) and incomplete in 40 patients (73%) after two cycles of therapy, and remission was complete in 32 patients (58%) and incomplete in 23 patients (42%) after the last treatment cycle. The percentage change in all PET/CT parameters except for the area under the curve of the cumulative standardized uptake value–volume histogram was significantly greater in complete response patients than in non‐complete response patients after two cycles and the last cycle. The Cox proportional hazard model and best subset selection method revealed that the percentage change of the sum of total lesion glycolysis after the last cycle (relative risk, 5.24; P = 0.003) was an independent predictor of progression‐free survival. The percent change of sum of total lesion glycolysis, calculated from PET/CT, can be used to quantify the response to treatment and can predict progression‐free survival after the last treatment cycle in patients with relapsed or refractory DLBCL treated with bendamustine–rituximab.     

继发性骨淋巴瘤的18F-FDG PET/CT影像诊断及与骨髓活检诊断效能的比较

目的:分析继发性骨淋巴瘤的PET/CT影像特点,比较骨髓活检（bone marrow biopsy,BMB）及PET/CT诊断骨淋巴瘤各自的优势,探讨如何进一步提高骨淋巴瘤的检出率。方法:回顾性分析放化疗前在我院行PET/CT检查的68例继发性骨淋巴瘤影像及骨髓活检资料。所有病例均病理确诊为淋巴瘤。骨淋巴瘤病灶的诊断标准:BMB阳性或骨局灶性FDG代谢增高且治疗后代谢减低或消失。采用SPSS 16.0统计分析不同分组的SUVmax及诊断效能差异。结果:PET/CT与BMB诊断灵敏度比较:68例中63例行BMB。PET/CT的总体诊断灵敏度及对非惰性淋巴瘤的诊断灵敏度高于BMB（P＜0.05）,而对惰性淋巴瘤,BMB灵敏度略高于PET/CT(P＞0.05)。PET/CT表现与BMB结果:根据PET/CT所见分为骨质破坏组（18例）和骨髓浸润组（50例）,骨质破坏组的SUVmax明显高于骨髓浸润组（P＜0.01）。骨质破坏组以弥漫大B细胞淋巴瘤（diffuse large B cell lymphoma,DLBCL）为主,PET/CT均阳性。骨髓浸润组PET/CT阳性41例,表现为局灶性增高、弥漫不均匀性增高和弥漫均匀性增高,弥漫均匀性增高组的SUVmax明显低于其它两组。BMB阴性21例,其中骨质破坏组8例,局灶性骨髓浸润13例。病理类型与PET/CT表现:31例DLBCL、10例其它侵袭性非霍奇金淋巴瘤（non-Hodgkin's lymphoma,NHL）及6例霍奇金淋巴瘤（Hodgkin's lymphoma,HL）均PET/CT阳性;18例惰性淋巴瘤PET/CT仅11例阳性。DLBCL的SUVmax明显高于惰性淋巴瘤（P＜0.05）。结论:继发性骨淋巴瘤骨髓浸润多于骨质破坏。骨质破坏和局灶性骨髓浸润多见于侵袭性骨淋巴瘤,而弥漫性骨髓浸润更多见于惰性淋巴瘤。PET/CT对骨质破坏、局灶性骨髓浸润的诊断优于BMB,而BMB对弥漫性骨髓浸润的诊断优于PET/CT。联合BMB和PET/CT才能更准确地诊断骨淋巴瘤。     

子宫内膜癌中错配修复蛋白表达缺失的意义

目的:评价MLH1、MSH2、PMS2和MSH6蛋白在子宫内膜癌中的表达缺失率,探讨MMR蛋白在子宫内膜癌发生、发展中的作用。方法:选取87例子宫内膜癌肿瘤组织,应用免疫组化方法检测子宫内膜癌组织中MLH1、MSH2、PMS2和MSH6蛋白的表达。结果:87例子宫内膜癌中MLH1、MSH2、PMS2和MSH6四种蛋白表达缺失率分别为12.6%(11/87)、2.3%(2/87)、16.1%(14/87)、6.9%(6/87),总的蛋白缺失率为31.0%(27/87)。MMR蛋白在不同年龄段的表达缺失率依次为:≤30岁为0%(0/2)、31-40岁为43.8%(7/16)、41-50岁为44.4%(12/27)、>50岁为19.0%(8/42)。I型子宫内膜样腺癌的MMR蛋白缺失率为36.9%,其中高级别的子宫内膜样腺癌中MMR蛋白表达缺失率为58.3%;II型子宫内膜癌中MMR蛋白的表达缺失率为13.6%。MMR蛋白在黏膜内癌、浅肌层浸润癌及深肌层浸润癌中的表达缺失率分别为14.3%(3/21)、29.6%(16/54)、66.7%(8/12),10例淋巴结转移的子宫内膜癌病例中有6例存在MMR蛋白的表达缺失。结论:MMR蛋白在低年龄段、高级别子宫内膜样腺癌、有深肌层浸润及淋巴结转移的子宫内膜癌病例中表达缺失率高,MMR蛋白在子宫内膜癌的进展中具有重要作用,建议临床常规检测子宫内膜癌中MMR蛋白的表达。     

Evaluation of thoracic tumors with 18F‐FMT and 18F‐FDG PET‐CT: A clinicopathological study

L‐[3‐¹⁸F]‐α‐methyltyrosine (¹⁸F‐FMT) is an aminoacid tracer for positron emission tomography (PET). The aim of this study was to determine whether PET‐CT with ¹⁸F‐FMT provides additional information for the preoperative diagnostic workup as compared with ¹⁸F‐FDG PET. PET‐CT studies with ¹⁸F‐FMT and ¹⁸F‐FDG were performed as a part of the preoperative workup in 36 patients with histologically confirmed bronchial carcinoma, 6 patients with benign lesions and a patient with atypical carcinoid. Expression of L‐type amino acid transporter 1 (LAT1), CD98, Ki‐67 labeling index, VEGF, CD31 and CD34 of the resected tumors were analyzed by immunohistochemical staining, and correlated with the uptake of PET tracers. For the detection of pulmonary malignant tumors, ¹⁸F‐FMT PET exhibited a sensitivity of 84% whereas the sensitivity for ¹⁸F‐FDG PET was 89% (p = 0.736). ¹⁸F‐FMT PET‐CT and ¹⁸F‐FDG PET‐CT agreed with pathological staging in 85 and 68%, respectively (p = 0.151). ¹⁸F‐FMT uptake was closely correlated with LAT1, CD98, cell proliferation and angiogenesis. The specificity of ¹⁸F‐FMT PET for diagnosing thoracic tumors was higher than that of ¹⁸F‐FDG PET. Our results suggest that coexpression of LAT1 and CD98 in addition to cell proliferation and angiogenesis is relavant for the progression and metastasis of lung cancer. © 2008 Wiley‐Liss, Inc.     

Progression Free Survival and Predictor of Recurrence in DLBCL patients with Negative Interim 18FDG PET/CT Using Standardized Imaging and Reporting Protocols

Background: To determine progression free survival (PFS) and predictor of recurrence in patients with diffuse large B-cell lymphoma (DLBCL) with negative interim 18FDG PET/CT (iPET) using standardized imaging and reporting protocols. Materials and Methods: This prospective study was conducted at PET/CT Section of a JCIA accredited healthcare facility from December 2015 till February 2020. Patients with DLBCL having complete metabolic response (CMR; Deauville score: 1-3) on iPET were selected and followed for a median period of 11 months (4-144 months).  End point response on follow-up PET/CT (either end of treatment or surveillance) was categorized as sustained CMR (sCMR) and disease recurrence. Kaplan Meier survival curve was used to measure PFS and receiver operating characteristics (ROC) was plotted for age, largest lesion size, highest standardized uptake value (SUVmax), disease stage and body mass index (BMI) on baseline scan to find their impact on recurrence. Results: Total 185 patients with DLBCL who had achieved CMR on iPET with a median age 55 years (19 – 88 yr.) with male predominance (63% male) were selected. On follow-up, 123 (66%) had sCMR while recurrence was found in 34% (p <0.05). No significant difference in demographics was found between two groups. Median PFS time was 34 months (22.8 – 45.1 months). On ROC analysis, only baseline highest SUVmax was found as a significant independent predictor of disease recurrence at a cut off >22.6 (highest area under curve: 0.595; SE 0.046; p <0.05). Conclusion: We conclude that recurrence is found in 34% of DLBCL patients with a negative interim 18FDG PET/CT using standardized imaging and reporting protocols. Despite of early response, these patients need continued intensive follow-up especially those with a baseline SUVmax > 22.6.     

A prospective evaluation of the utility of 2‐deoxy‐2‐[18F]fluoro‐D‐glucose positron emission tomography and computed tomography in staging locally advanced gastric cancer

BACKGROUND:

The aim of this study was to examine prospectively the utility of adding preoperative [¹⁸F]fluorodeoxyglucose positron emission tomography (FDG‐PET)/computed tomography (CT) to routine CT, endoscopic ultrasound (EUS), and laparoscopic staging of localized gastric cancer.

METHODS:

Patients with locally advanced gastric/gastroesophageal cancer were screened for 2 institutional review board–approved Memorial Sloan‐Kettering Cancer Center neoadjuvant chemotherapy protocols. Locally advanced disease was defined as T3 or T4, or lymph node–positive, based on EUS and high‐resolution CT scan. All patients underwent both standard FDG‐PET/CT and laparoscopy with cytological examination of washings. The sensitivity and specificity of FDG‐PET/CT for the identification of metastatic disease not seen on CT was determined. An economic model using Medicare/Medicaid reimbursement charges was developed to assess the cost‐effectiveness of these interventions.

RESULTS:

A total of 113 patients were enrolled from 2003 to 2010. All patients were assessed as having locally advanced disease by CT/EUS. FDG uptake in the primary tumor was associated with male sex, proximal tumors, and nondiffuse Lauren's subtype. 31 (27%) patients had occult metastatic disease detected by PET/CT (n = 11, 10%) and/or laparoscopy (n = 21, 19%), with a single overlap. Economic modeling suggests that the addition of FDG‐PET/CT to the standard staging evaluation of patients with locally advanced gastric cancer resulted in an estimated cost savings of ～US $13,000 per patient.

CONCLUSIONS:

FDG‐PET/CT identifies occult metastatic lesions in approximately 10% of patients with locally advanced gastric cancer. Because of reduced morbidity from fewer futile surgeries and lower patient care costs, PET/CT should be considered as a component of the standard staging algorithm for localized gastric cancer. Cancer 2012. © 2012 American Cancer Society.     

FDG PET/CT as a diagnostic and prognostic tool for the evaluation of marginal zone lymphoma

We evaluated the role of 18‐fluoro‐2‐deoxy‐d ‐glucose positron emission tomography (^[18F] FDG‐PET) with computed tomography (CT) (PET/CT) as a diagnostic and prognostic tool in newly diagnosed marginal zone lymphoma (MZL) patients. This is a retrospective cohort study of patients with newly diagnosed MZL, treated with immunotherapy, chemotherapy regimens, surgery, or Helicobacter pylori eradication between 2008 and 2016 in a single tertiary center. Only patients who had a pretreatment PET/CT (P‐PET/CT) were included. P‐PET/CT, interim (I‐PET/CT), and end‐of‐treatment PET/CT (E‐PET/CT) studies were reviewed. P‐PET/CT results were reported using two methods of evaluation, qualitative and semi quantitative: visual assessment (VAS) and maximal standardized uptake value (SUVmax), and I‐PET and E‐PET results were reported by Deauville 5‐point score (DS) evaluation as well. Avidity of PET/CT was defined as abnormal uptake in any of these methods. The primary outcome was the prognostic role of P‐PET/CT, I‐PET/CT, and E‐PET/CT on progression‐free survival (PFS) and overall survival (OS). Data of 196 patients with MZL were identified, 110 of which had P‐PET/CT and were included in this analysis. Median age was 67 years (range 18‐93). The median follow‐up period was 63 months (range 3‐278). The median OS and PFS for the whole cohort were 63 (interquartile range 39‐85) and 60 (interquartile range 37‐76) months, respectively. The avidity of PET at baseline for the whole cohort was 70% (77/110 patients), for MALT lymphoma, 62.5% (40/64 patients), for NMZL, 76.4% (13/17 patients), and for SMZL, 82.7% (24/29 patients). When adjusted for IPI, sex, and comorbidities, positive E‐PET/CT was associated with reduced PFS with a hazard ratio (HR) of 3.4 (95% CI, 1.27‐9.14, P = 0.02). Positive E‐PET/CT did not correlate with OS. However, there were only three events. P‐PET/CT was not predictive of PFS or OS. Our study demonstrates that above 70% of MZL are FDG avid. Positive E‐PET/CT is a strong prognostic factor for PFS.     

Indeterminate pulmonary nodules on CT images in breast cancer patient: The additional value of 18F-FDG PET/CT

Aim: To assess the potential role of 18F‐Fluorodeoxiglucose (FDG) Positron Emission Tomography (PET)/Computed Tomography (CT) in characterizing indeterminate lung nodules detected at CT scan in patients previously treated for a breast cancer (BC). Materials and Methods: Twenty‐nine consecutive BC patients (28 females, mean age 65 ± 12 years) with evidence of indeterminate lung nodules at contrast‐enhanced CT (CECT) scan (lesions with axial diameter ≥8 mm) were retrospectively analysed: all patients underwent 18F‐FDG PET/CT within a mean 2 ± 1 months from CECT imaging. PET/CT was considered positive in the presence of abnormal FDG uptake in the pulmonary nodules and/or in other organs. The nature of lung nodules was defined at histopathology and/or imaging follow‐up. Results: Fourteen (48%) patients showed negative and 15 (52%) positive PET/CT scan in the lungs: of these 15 patients, 7 (47%) had pathologic FDG‐uptake in lungs only, whereas 8 (53%) showed abnormal FDG‐uptake also in sites different from lungs. At histology and/or imaging follow‐up, five (17%) patients were considered positive for BC lung metastases while in seven (24%) a second cancer was diagnosed. In this subset of patients, the sensitivity and specificity for FDG PET/CT in revealing lung lesions were 17% and 100%, respectively, for nodules <8 mm in diameter, and 77% and 85%, respectively, for nodules with diameter ≥8 mm. The therapeutic planning was changed to surgery in seven patients, chemotherapy in one patient and continued hormonal therapy in five. The inclusion of PET/CT in the diagnostic algorithm of the evaluated patients helped avoid unnecessary over‐treatment in 12 of 29 patients. Conclusion: FDG PET/CT appears useful in characterizing indeterminate lung nodules found at CECT scan in BC patients, with a sensitivity that is proportional to nodule size. In addition, PET/CT helped in avoiding over‐treatment in a significant proportion of patients.     

淋巴瘤单发骨病变的18F－FDGPET／CT影像学分析

目的：研究原发性骨淋巴瘤与单发继发性淋巴瘤骨髓浸润的18 F －FDG PET／CT 影像学表现,探讨18 F－FDG PET／CT 对原发性骨淋巴瘤的诊断及鉴别诊断价值。方法：回顾性分析经病理证实的25例单发骨淋巴瘤的18 F －FDG PET／CT 影像学资料。结果：25例骨淋巴瘤均为单发,其中14例位于脊柱骨,10例位于附肢骨,1例位于肋骨。15例为原发性骨淋巴瘤,10例为继发性淋巴瘤骨髓浸润。原发性骨淋巴瘤15例中非霍奇金淋巴瘤11例,霍奇金淋巴瘤4例;继发性淋巴瘤骨髓浸润10例中非霍奇金淋巴瘤7例,霍奇金淋巴瘤3例。25例骨淋巴瘤中23例 CT 表现为骨质密度异常改变,2例病变骨质密度未见明显异常改变。病变 FDG摄取不同程度增高,SUVmax范围为2．6～24．5。原发性骨淋巴瘤及继发性淋巴瘤骨髓浸润病变 SUVmax经 Mann－Whitney U 检验提示原发性骨淋巴瘤与继发性淋巴瘤骨髓浸润病变 SUVmax有差异（P ＝0．007）。结论：原发性骨淋巴瘤18 F －FDG PET／CT 影像学表现有一定的特征性,分析其表现对原发性和继发性骨淋巴瘤的诊断及鉴别诊断有一定的临床价值。     

The value of [(18)F]fluorodeoxyglucose positron emission tomography/computed tomography in extranodal natural killer/T-cell lymphoma

PurposeTo our knowledge, there are no published data pertinent to the use of [¹⁸F]fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) in patients with natural killer (NK)/T—cell lymphoma. The purpose of this study was to assess the value of FDG PET/CT in this aggressive type of non-Hodgkin lymphoma.Patients and MethodsAll patients with NK/T-cell lymphoma referred for FDG PET/CT at our institution from July 2001 to July 2006 were retrospectively studied. PET/CT examinations were blindly reviewed by 2 experienced readers. The results were compared with the status of the disease, which was determined after evaluation of biopsy, laboratory, clinical and conventional imaging examination, and follow-up results. PET/CT results were thereby classified as true-positive, true-negative, false-positive, or false-negative. The degree of FDG uptake in the positive lesions was semiquantified using maximum standard uptake value (SUV_max).ResultsTwenty-one PET/CT examinations were performed in 10 patients with NK/T-cell lymphoma. For nasal disease, PET/CT was true-positive in 5 cases, true-negative in 15 cases, and positive but unconfirmed in 1 case. For extranasal disease, PET/CT was true-positive in 3 cases, true-negative in 16 cases, and false-negative in 2 cases. The mean SUV_max in PET-positive lesions in nasal cavities or paranasal sinuses was 16 gm/mL (range, 5–25 gm/mL; median, 19.3 gm/mL). In extranasal disease, the mean SUV_max was 10.9 gm/mL (range, 4.6–34.1 gm/mL; median, 5.6 gm/mL).ConclusionViable NK/T-cell lymphoma is intensely FDG hypermetabolic. PET/CT appears to be sensitive for the detection of disease in the nasopharynx and, to a lesser extent, in extranasal sites.     

Clinical implications of 18F-fluorodeoxyglucose positron emission tomography/computed tomography at delayed phase for diagnosis and prognosis of malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) has a poor prognosis, and conventional imaging modalities do not reflect the prognosis of MPM. In this study, the clinical significance of 18F-fluorodeoxyglucose positron emission tomography/computed tomography fusion imaging (18F-FDG PET/CT) was evaluated for the differential diagnosis, staging and prognosis in MPM patients. Ninety patients who underwent 18F-FDG PET/CT scanning due to a clinical diagnosis or suspicion of MPM prior to therapy were reviewed. Of 90 patients, 31 were pathologically diagnosed as MPM. Maximum standardized uptake values (SUVmax) were semi-quantitatively obtained from PET/CT 60 min (early phase) and 120 min (delayed phase) after injection of 18F-FDG, and the clinicopathological correlations with the level of SUVmax obtained from PET/CT were examined. The survival curves of MPM patients were plotted according to the methods of Kaplan-Meier. The prognostic implications of the level of SUVmax were estimated by t-test. PET/CT scan showed intense abnormal FDG uptake (SUVmax>2.0) in the pleural lesions of all 31 MPM patients at delayed phase, while it showed abnormal FDG uptake in 30 (97%) patients at early phase. In all 31 MPM patients, the values of SUVmax at delayed phase were higher than those at the early phase. PET/CT also indicated metastasis in the lymph node in 7 patients (23%) and in the systemic lesions in 8 patients (26%) with MPM. Twenty-three MPM patients with high SUVmax, whose prognosis was apparent, showed significantly poorer prognosis in both early and delayed phase (respectively, p=0.03 and p=0.01, t-test). The results showed that 18F-FDG PET/CT at delayed phase is very useful for the diagnosis of pleural diseases, and SUVmax on PET/CT in the delayed phase is a more reliable prognostic factor than that in the early phase. High uptake of 18F-FDG PET/CT may be a predictive factor of prognosis in MPM patients.