Incidental focal colorectal 18F-fluorodeoxyglucose uptake on positron emission tomography/computed tomography

AIM: To assess the clinical significance of incidental focal colorectal 18 F-fluorodeoxyglucose ( 18 F-FDG) uptake on 18 F-FDG-positron emission tomography/computed tomography (PET/CT). METHODS: The records of all the cases which had undergone colonoscopy after PET/CT within a two weeks interval were reviewed. Adenomas were considered advanced when they were villous, ≥ 10 mm in size, or had high-grade dysplasia. Colorectal cancers and advanced adenomas are collectively referred to as advanced colorectal neoplasms. Receiver-operating characteristic curve analysis was used to determine thesignificant predictive maximum standardized uptake value (SUVmax) cutoff value for advanced colorectal neoplasms and cancer. RESULTS: Ninety-five colorectal lesions matched the site of incidental focal colorectal 18 F-FDG uptake on PET/CT and 146 did not. Colonoscopy showed advanced colorectal neoplasms corresponding to the site of 18 F-FDG uptake in 49 of the 95 (51.5%) lesions with incidental uptake. Of the lesions without incidental uptake, only 6 of 146 (4.1%) had advanced colorectal neoplasms on colonoscopy, indicating a statistically significant difference between the two groups (P < 0.001). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of incidental focal 18 F-FDG uptake in identifying advanced colorectal neoplasms were 89.1%, 75.3%, 51.6%, 95.9%, and 78.4%, respectively. In detecting only CRC, these values were 89.2%, 69.6%, 34.7%, 97.3%, and 72.6%, respectively. The significant SUVmax cutoff value for advanced colorectal neoplasms (area under the curve 0.755, P < 0.001) was 4.35, with a sensitivity, specificity, PPV, NPV, and accuracy of 75.5%, 65.2%, 69.8%, 71.4% and 70.5%, respectively. For CRC, 5.05 was the significant SUVmax cutoff value (area under the curve 0.817, P < 0.001), with a sensitivity, specificity, PPV, NPV, and accuracy of 84.8%, 71.0%, 80.9%, 89.8%, and 75.8%, respectively. CONCLUSION: The presence of incidental focal colorectal 1     

推进18F-FDG PET/CT显像在心血管炎症的临床应用

炎症是多种心血管疾病的主要致病因素或重要病理特征,对其进行精准评价具有重要的临床意义。18氟标记脱氧葡萄糖正电子发射型计算机断层扫描显像(18F-FDG PET/CT)作为功能性影像技术,能特异地显示炎症活性。近年来的研究表明,18F-FDG PET/CT在动脉粥样硬化、感染性心内膜炎、心脏结节病、急性心肌梗死和血管炎等疾病的诊断、鉴别诊断、治疗决策制定和预后评估等方面具有独特的价值。随着PET/CT在我国的加快普及和推广,有望在心血管炎症疾病的诊疗中发挥更大的作用。     

18F-NaF positron emission tomography/computed tomography in voriconazole-induced periostitis

Clinical Rheumatology -     

Thoracic positron emission tomography: 18F-fluorodeoxyglucose and beyond

Ongoing technologic and therapeutic advancements in medicine are now testing the limits of conventional anatomic imaging techniques. The ability to image physiology, rather than simply anatomy, is critical in the management of multiple disease processes, especially in oncology. Nuclear medicine has assumed a leading role in detecting, diagnosing, staging and assessing treatment response of various pathologic entities, and appears well positioned to do so into the future. When combined with computed tomography (CT) or magnetic resonance imaging (MRI), positron emission tomography (PET) has become the sine quo non technique of evaluating most solid tumors especially in the thorax. PET/CT serves as a key imaging modality in the initial evaluation of pulmonary nodules, often obviating the need for more invasive testing. PET/CT is essential to staging and restaging in bronchogenic carcinoma and offers key physiologic information with regard to treatment response. A more recent development, PET/MRI, shows promise in several specific lung cancer applications as well. Additional recent advancements in the field have allowed PET to expand beyond imaging with ¹⁸F-flurodeoxyglucose (FDG) alone, now with the ability to specifically image certain types of cell surface receptors. In the thorax this predominantly includes ⁶⁸Ga-DOTATATE which targets the somatostatin receptors abundantly expressed in neuroendocrine tumors, including bronchial carcinoid. This receptor targeted imaging technique permits targeting these tumors with therapeutic analogues such as ¹⁷⁷Lu labeled DOTATATE. Overall, the proper utilization of PET in the thorax has the ability to directly impact and improve patient care.     

Diagnostic role of 18F-fluorodeoxyglucose positron emission tomography for follicular lymphoma with gastrointestinal involvement

AIM:To investigate the capacity for 18F-fluorodeoxyglucose(18F-FDG) positron emission tomography(PET) to evaluate patients with gastrointestinal lesions of follicular lymphoma.METHODS:This retrospective case series consisted of 41 patients with follicular lymphoma and gastrointestinal involvement who underwent 18F-FDG-PET and endoscopic evaluations at ten different institutions between November 1996 and October 2011.Data for endoscopic,radiological,and biological examinations performed were retrospectively reviewed from clinical records.A semi-quantitative analysis of 18F-FDG uptake was performed for each involved area by calculating the maximum standardized uptake value(SUVmax).Based on the positivity of 18F-FDG uptake in the gastrointestinal lesions analyzed,patients were subdivided into two groups.To identify potential predictive factors for 18F-FDG positivity,these two groups were compared with respect to gender,age at diagnosis of lymphoma,histopathological grade,pattern of follicular dendritic cells,mitotic rate,clinical stage,soluble interleukin-2 receptor levels detected by 18F-FDG-PET,lactate dehydrogenase(LDH) levels,hemoglobin levels,bone marrow involvement,detectability of gastrointestinal lesions by computed tomography(CT) scanning,and follicular lymphoma international prognostic index(FLIPI) risk.RESULTS:Involvement of follicular lymphoma in the stomach,duodenum,jejunum,ileum,cecum,colon,and rectum was identified in 1,34,6,3,2,3,and 6 patients,respectively.No patient had esophageal involvement.In total,19/41(46.3%) patients exhibited true-positive 18F-FDG uptake in the lesions present in their gastrointestinal tract.In contrast,false-negative 18F-FDG uptake was detected in 24 patients(58.5%),while false-positive 18F-FDG uptake was detected in 5 patients(12.2%).In the former case,2/19 patients had both 18F-FDG-positive lesions and 18F-FDGnegative lesions in the gastrointestinal tract.In patients with 18F-FDG avidity,the SUVmax value of the involved gastrointestinal tract ranged from 2.6 to 17.4(median:4.7).For the 18F-FDG-negative(n = 22) and-positive(n = 19) groups,there were no differences in the male to female ratios(10/12 vs 4/15,P = 0.186),patient age(63.6 ± 2.4 years vs 60.1 ± 2.6 years,P = 0.323),presence of histopathological grade 1 vs 2(20/2 and 17/2,P = 1.000),follicular dendritic cell pattern(duodenal/nodal:13/5 vs 10/3,P = 1.000),mitotic rate(low/partly high,14/1 vs 10/3,P = 0.311),clinical stage according to the Ann Arbor system(stages ⅠE and ⅡE/other,15/7 vs 15/4,P = 0.499),clinical stage according to the Lugano system(stages Ⅰ and Ⅱ-1/other,14/8 vs 14/5,P = 0.489),soluble interleukin-2 receptor levels(495 ± 78 vs 402 ± 83,P = 0.884),LDH levels(188 ± 7 vs 183 ± 8,P = 0.749),hemoglobin levels(13.5 ± 0.3 vs 12.8 ± 0.4,P = 0.197),bone marrow involvement(positive/negative,1/8 vs 1/10,P = 1.000),detectability by CT scanning(positive/negative,1/16 vs 4/13,P = 0.335),and FLIPI risk(low risk/other,16/6 vs 13/6,P = 0.763),respectively in each case.CONCLUSION:These findings indicate that it is not feasible to predict 18F-FDG-avidity.Therefore,18FFDG-PET scans represent a complementary modality for the detection of gastrointestinal involvements in follicular lymphoma patients,and surveillance of the entire gastrointestinal tract by endoscopic examinations is required.     

Advantages of 18F-fluorodeoxyglucose positron emission tomography combined with computed tomography in detecting post cardiac surgery infections

The 18F-fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG-PET/CT) offers an excellent negative predictive value. Consequently, it is a reliable tool for excluding an infectious phenomenon in case of negativity. In case of persistent fever of unknown origin after cardiac surgery and in combination with other bacteriological examinations and medical imaging, we can rely on FDG-PET/CT to confirm or eliminate deep infections and prosthetic endocarditis. For this reason, FDG-PET/CT should be considered among the examinations to be performed in case of suspected infection after cardiac surgery. We have reported the case of a 76-year-old man who presented with a fever of unknown origin and recurrent septic shocks after a biological Bentall procedure combined with left anterior descending (LAD) coronary artery revascularization by the left internal thoracic artery. We performed a FDG-PET/CT which showed external iliac vein and right common femoral vein hyperfixation with infiltration of adjacent soft tissues, highly suspected to be an infectious process.

Learning objective

The aim of this case report is to show that FDG-PET/CT, in combination with other bacteriological examinations and medical imaging, can be extremely helpful in detecting deep infectious sources, even during the early postoperative period.     

Evaluation of organ involvement in intravascular large B-cell lymphoma by 18F-fluorodeoxyglucose positron emission tomography

To evaluate the role of (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) in intravascular large B-cell lymphoma (IVLBCL), we retrospectively analyzed four consecutive IVLBCL patients receiving FDG-PET before treatment between May 2006 and November 2007. Patients were two men and two women (median age 62 years, range 54-76 years). All patients received bone marrow biopsies and random skin biopsies and two of the four patients underwent renal biopsy for diagnosis. Accuracy of FDG-PET for the detection of organ involvements was analyzed by comparing results of pathological findings. Concordant results with respect to bone marrow involvement were accurately obtained for two patients. Skin and renal involvements were undetectable by FDG-PET regardless of positive pathological findings. One patient with a false-negative FDG-PET result showed fewer lymphoma cells in the bone marrow specimen than patients with concordant FDG-PET results. These results suggest false-negative results for some types of organ involvement. Careful interpretation of the results of FDG-PET in IVLBCL is thus required.     

18F-fluorodeoxyglucose positron emission tomography in a case of retroperitoneal fibrosis

A patient with recurrent abdominal pain was admitted to our hospital. Computed tomography showed a soft dense mass surrounding the abdominal aorta at the infrarenal level, which was compatible with retroperitoneal fibrosis. (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography showed abnormal uptake of (18)F-FDG into these lesions. Two months after the initiation of corticosteroid therapy, the abnormal uptake of (18)F-FDG had ceased along with a reduction in the fibrous mass surrounding the abdominal aorta.     

18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) does not visualize follicular lymphoma of the duodenum

<p>18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) has been used as a potential tool for imaging nodal follicular lymphoma (FL) and extranodal spread. As primary intestinal FL is increasingly being recognized, we have performed a study to investigate the usefulness of 18F-FDG-PET for staging of extranodal FL within the gastrointestinal tract. In eight patients with a diagnosis of FL localized in the duodenum (six cases in stage I and one each in stages II and IV, respectively) whole body 18F-FDG-PET scans were performed. Seven patients with duodenal FL were rated WHO grade 1 and one had FL grade 3, while both patients with secondary spread had FL WHO grade 1. All patients were imaged before initiation of therapy. None of the patients with primary duodenal FL showed pathologically elevated 18F-FDG uptake. 18F-FDG-PET findings were not influenced by histological grade or proliferative activity of FL. These findings suggest that 18F-FDG-PET is not useful for clinical assessment of primary duodenal FL.     

Clinical role of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in post-operative follow up of gastric cancer： Initial results

AIM： To evaluate the clinical role of 18F-fluorodeo-xyglucose positron emission and computed tomography （18F-FDG PET/CT） in detection of gastric cancer recurrence after initial surgical resection. METHODS： In the period from January 2007 to May 2008, 23 patients who had previous surgical resection of histopathologically diagnosed gastric cancer underwent a total of 25 18F-FDG PET/CT scans as follow-up visits in our center. The standard of reference for tumor recurrence consisted of histopathologic confirmation or clinical follow-up information for at least 5 mo after PET/CT examinations. RESULTS： PET/CT was positive in 14 patients （61%） and negative in 9 （39%）. When correlated with final diagnosis, which was confirmed by histopathologic evidence of tumor recurrence in 8 of the 23 patients （35%） and by clinical follow-up in 15 （65%）, PET/CT was true positive in 12 patients, false positive in 2, true negative in 8 and false negative in 2. Overall, the accuracy of PET/CT was 82.6%, the negative predictive value （NPV） was 77.7%, and the positive predictive value （PPV） was 85.7%. The 2 false positive PET/CT findings were actually chronic inflammatory tissue lesions. For the two patients with false negativePET/CT, the f inal diagnosis was recurrence of mucinous adenocarcinoma in the anastomosis in one patient and abdominal wall metastasis in the other. Importantly, PET/CT revealed true-positive findings in 11 （47.8%） patients who had negative or no definite findings by CT. PET/CT revealed extra-abdominal metastases in 7 patients and additional esophageal carcinoma in one patient. Clinical treatment decisions were changed in 7 （30.4%） patients after introducing PET/CT into their conventional post-operative follow-up program. CONCLUSION： Whole body 18F-FDG PET/CT was highly effective in discriminating true recurrence in post-operative patients with gastric cancer and had important impacts on clinical decisions in a considerable portion of patients.     

Attenuation-corrected 99mTc-tetrofosmin single-photon emission computed tomography in the detection of viable myocardium: comparison with positron emission tomography using 18F-fluorodeoxyglucose

Objectives. The purpose of this study was to assess the efficacy of attenuation-corrected (AC) technetium-99m (^99mTc)-tetrofosmin single-photon emission computed tomography (SPECT) in detecting viable myocardium compared to ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET).Background. The role of ^99mTc-labeled perfusion tracers in the assessment of myocardial viability remains controversial. Attenuation artifacts affect the diagnostic accuracy of SPECT images.Methods. Twenty-four patients with coronary artery disease (mean left ventricular ejection fraction 30%) underwent resting ^99mTc-tetrofosmin SPECT and FDG PET imaging. Both AC and non–attenuation-corrected (NC) SPECT images were generated.Results. Using a 50% threshold for viability by FDG PET, the percentage of concordant segments of viability between ^99mTc-tetrofosmin and FDG on the patient basis increased from 79.8% ± 14.0% (mean ± SD) on the NC images to 90.8% ± 10.6% on the AC images (p = 0.002). The percentage of ^99mTc-tetrofosmin defect segments within PET-viable segments, an estimate for the degree of underestimation of viability, decreased from 19.8% ± 15.2% on the NC images to 9.7% ± 12.6% on the AC images (p = 0.01). Similar results were obtained when a 60% threshold was used to define viability by FDG PET. When the anterior-lateral and inferior-septal regions were separately analyzed, the effect of attenuation correction was significant only in the inferior-septal region.Conclusions. The results indicate that AC ^99mTc-tetrofosmin SPECT improves the detection of viable myocardium mainly by decreasing the underestimation of viability particularly in the inferior-septal region, although some underestimation/overestimation of viability may still occur even with attenuation correction.     

~(18)F-Fluorodeoxyglucose positron emission tomography/computed tomography comparison of gastric lymphoma and gastric carcinoma

AIM To compare ~(18)F-fluorodeoxyglucose positron emission tomography/computed tomography(~(18)F-FDG PET/CT) features in gastric lymphoma and gastric carcinoma.METHODS Patients with newly diagnosed gastric lymphoma or gastric carcinoma who underwent ~(18)F-FDG PET/CT prior to treatment were included in this study. We reviewed and analyzed the PET/CT features of gastric wall lesions,including FDG avidity,pattern(focal/diffuse),and intensity [maximal standard uptake value:(SUVmax)]. The correlation of SUVmax with gastricclinicopathological variables was investigated by χ~2 test,and receiver-operating characteristic(ROC) curve analysis was performed to determine the differential diagnostic value of SUVmax-associated parameters in gastric lymphoma and gastric carcinoma. RESULTS Fifty-two patients with gastric lymphoma and 73 with gastric carcinoma were included in this study. Abnormal gastric FDG accumulation was found in 49 patients(94.23%) with gastric lymphoma and 65 patients(89.04%) with gastric carcinoma. Gastric lymphoma patients predominantly presented with type Ⅰ and type Ⅱ lesions,whereas gastric carcinoma patients mainly had type Ⅲ lesions. The SUVmax(13.39 ± 9.24 vs 8.35 ± 5.80,P 0.001) and SUVmax/THKmax(maximal thickness)(7.96 ± 4.02 vs 4.88 ± 3.32,P 0.001) were both higher in patients with gastric lymphoma compared with gastric carcinoma. ROC curve analysis suggested a better performance of SUVmax/THKmax in the evaluation of gastric lesions between gastric lymphoma and gastric carcinoma in comparison with that of SUVmax alone.CONCLUSION PET/CT features differ between gastric lymphoma and carcinoma,which can improve PET/CT evaluation of gastric wall lesions and help differentiate gastric lymphoma from gastric carcinoma.     

~（18）F-fluorodeoxyglucose positron emission tomography in the diagnosis of small pancreatic cancer

AIM:To investigate the role of 18 F-fluorodeoxyglucose positron emission tomography(FDG-PET) in the diagnosis of small pancreatic cancer. METHODS:This study involved 31 patients with proven invasive ductal cancer of the pancreas.The patients were divided into 3 groups according to the maximum diameter of the tumor:TS1(maximum tumor size≤2.0 cm) ,TS2(>2.0 cm and≤4.0 cm) or TS3-4(>4.0 cm) .The relationships between the TS and various diagnostic tools,including FDG-PET with dual time point evaluation,were anal...     

Value of contrast-enhanced 18F-fluorodeoxyglucose positron emission tomography/computed tomography in detection and presurgical assessment of pancreatic cancer: a prospective study

Background and Aim: Positron Emission Tomography (PET) using ¹⁸F‐fluorodeoxyglucose (FDG) associated with computed tomography (CT) is increasingly used for the detection and the staging of pancreatic cancer, but data regarding its clinical added value in pre‐surgical planning is still lacking. The aim of this study is to investigate the performance of FDG PET associated with contrast‐enhanced CT in detection of pancreatic cancer. Methods: We prospectively evaluated FDG PET/CT studies obtained in patients with suspicion of operable pancreatic cancer between May 2006 and January 2008. Staging was conducted according to a standardized protocol, and findings were confirmed in all patients by surgical resection or biopsy examination. Results: Forty‐five patients with a median age of 69 (range 22–82) were included in this study. Thirty‐six had malignant tumors and nine had benign lesions (20%). The sensitivity of enhanced versus unenhanced PET/CT in the detection of pancreatic cancer was 96% versus 72% (P = 0.076), the specificity 66.6% versus 33.3% (P = 0.52), the positive predictive value 92.3% versus 80% (P = 0.3), the negative predictive value 80% versus 25% (P = 0.2), and the accuracy 90.3% versus 64% (P = 0.085). Conclusions: Our preliminary data obtained in a limited number of patients shows that contrast‐enhanced FDG PET/CT offers good sensitivity in the detection and assessment of pancreatic cancer, but at the price of a relatively low specificity. Enhanced PET/CT seems to be superior to unenhanced PET/CT. Further larger prospective studies are needed to establish its value for pre‐surgical diagnosis and staging in pancreatic cancer.