Value of (18)F-FDG-PET/CT in patients with fever of unknown origin and unexplained prolonged inflammatory syndrome: a single centre analysis experience

Objective: The aim of our study was to evaluate the diagnostic contribution of ¹⁸F‐fluoro‐deoxyglucose (¹⁸F‐FDG)‐positron emission tomography (PET)/computed tomography (CT) in patients with fever of unknown origin (FUO) or unexplained prolonged inflammatory syndrome (UPIS) in real life. Patients and methods: We performed a retrospective study including 14 patients with FUO or UPIS hospitalised in our institution (Strasbourg University Hospital, France) between January 2005 and July 2006. ¹⁸F‐FDG‐PET/CT was considered helpful when abnormal results allowed an accurate diagnosis. Results: ¹⁸F‐FDG‐PET/CT was helpful in half the patients (7/14) for final diagnosis. A diagnosis was reached in 87.5% of the patients (7/8) with an abnormal ¹⁸F‐FDG‐PET/CT but only in 50% of the patients (3/6) with a normal ¹⁸F‐FDG‐PET/CT. Conventional chest and abdominal CT was performed in 13 patients before ordering ¹⁸F‐FDG‐PET/CT. We considered that ¹⁸F‐FDG‐PET/CT was essential to establish the final diagnosis in only 23% of the patients (3/13) since neither chest nor abdominal CT identified abnormalities consistent with the final diagnosis. However, among the three patients, two were diagnosed with large vessel vasculitis and one patient with local prosthetic infection. Conclusions: Our study supports the potential interest of ¹⁸F‐FDG‐PET/CT in the diagnostic workup of FUO and UPIS as it helped establish a fine diagnosis in half of the cases. However, ¹⁸F‐FDG‐PET/CT appeared to be essential to the final diagnosis in only 23% of the cases. In our opinion, this protocol should be performed as a second level test, especially when conventional CT is normal or is unable to discriminate between active and silent lesions.     

Follicular thyroid adenoma with eggshell calcification presenting as an intensely hypermetabolic lesion on 18F‐FDG PET/CT

We report herein a case of follicular thyroid adenoma with an eggshell calcification presenting as an intensely hypermetabolic lesion on combined ¹⁸F‐fluorodeoxyglucose whole‐body PET and CT (¹⁸F‐FDG PET/CT) performed for staging work‐up in a 68‐year‐old woman who had undergone distal gastrectomy with Billroth II anastomosis for early gastric carcinoma. The mass was intensely hypermetabolic (SUV_max = 21.3 g/mL) on combined ¹⁸F‐FDG PET/CT, hypoechoic with an interrupted eggshell calcification on gray‐scale ultrasonography (US), and showed intranodular vascularity on power Doppler US. Follicular adenoma should be considered in the differential diagnosis of a mass with an eggshell calcification on US and intense hypermetabolism on ¹⁸F‐FDG PET/CT. © 2009 Wiley Periodicals, Inc. J Clin Ultrasound, 2010     

Whole-Body [18F]FDG-PET/MRI vs. [18F]FDG-PET/CT in Malignant Melanoma

Purpose

To assess the diagnostic performance of simultaneous whole-body 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG) positron emission tomography (PET)/magnetic resonance imaging (MRI) compared to [¹⁸F]FDG PET/x-ray computed tomography (CT) for detection of distant metastatic disease in patients with malignant melanoma.

Procedures

We included patients with malignant melanoma who underwent a single injection [¹⁸F]FDG dual-imaging protocol that included whole-body PET/CT and subsequent whole-body PET/MRI for staging or restaging purposes in a prospective setting. Images from both modalities were analyzed by two rater teams for the presence of metastatic lesions. PET/CT–PET/MRI overall agreement as well as region-based accuracies, sensitivities (Se), and specificities (Sp) were computed.

Results

Between July 2014 and December 2018, 22 patients were enrolled. Interrater agreement and overall accuracy (consensus reading) were 78.8 % (95 % CI 71–84.9) and 96.1 % (95 % CI 92.3–98) for PET/MRI and 78 % (70.2–84.3) and 97.4 % (95 % CI 93.7–98.9) for PET/CT, respectively (P?=?0.42). PET/MRI reached a region-based Se of 89.1 % (95 % CI 79.4–94.5) and a Sp of 100 %, whereas PET/CT showed a region-based Se of 92.7 % (95 % CI 84–96.9) and a Sp of 100 % for the detection of metastatic disease in malignant melanoma.

Conclusions

Whole-body [¹⁸F]FDG-PET/MRI appears to be comparable to [¹⁸F]FDG-PET/CT for lesion detection in patients with malignant melanoma.

     

PET/CT to detect adverse reactions to metal debris in patients with metal‐on‐metal hip arthroplasty: an exploratory prospective study

Metal‐on‐metal (MoM) bearings in total hip arthroplasties and hip resurfacing arthroplasties have recently shown a new type of complication: adverse reactions to metal debris (ARMD). ARMD is characterized by local severe inflammation and tissue necrosis leading to implant failures. The gluteal muscle region is important for the patient outcome after revision surgery. This prospective positron emission tomography/computed tomography (PET/CT) study was undertaken to evaluate the characteristics of 2‐deoxy‐2‐[¹⁸F]fluoro‐d ‐glucose ([¹⁸F]FDG) and [⁶⁸Ga]Gallium citrate ([⁶⁸Ga]Citrate) PET/CT in ARMD patients. [¹⁸F]FDG and [⁶⁸Ga]Citrate PET/CT were performed in 18 hip arthroplasty patients: 12 ARMD patients (with 16 MoM hips) and six arthroplasty controls without ARMD. Tracer uptake was evaluated visually, and maximum standardized uptake (SUV_max) was measured in the gluteal muscle region. ARMD severity was graded by metal artefact reduction sequence‐magnetic resonance imaging (MARS‐MRI). Periprosthetic [¹⁸F]FDG uptake was observed in 15 of 16 hips, [⁶⁸Ga]Citrate uptake in three of 16 hips, respectively. The distribution of tracer uptake resembled infection in three hips. In the gluteal muscle region, the SUV_max of [¹⁸F]FDG was significantly greater in hips with moderate and severe ARMD compared with the controls (P = 0·009 for [¹⁸F]FDG and P = 0·217 for [⁶⁸Ga]Citrate). In patients who needed revision surgery, an intraoperative finding of gluteal muscle necrosis was associated with increased local SUV_max as detected by preoperative [¹⁸F]FDG (P = 0·039), but not by [⁶⁸Ga]Citrate (P = 0·301). In conclusion, the inflammatory reaction to metal debris in hip arthroplasty patients is best visualized with [¹⁸F]FDG.     

Prospective Comparison of FDG and FET PET/CT in Patients with Head and Neck Squamous Cell Carcinoma

Aim  The clinical usefulness of 2-deoxy-2-[F-18]fluoro-D-glucose-positron emission tomography (FDG-PET) in head and neck squamous cell carcinoma (HNSCC) is now well-documented. However, its sensitivity is greater than its specificity due to false-positive results in inflammatory or infectious lesions, which are frequent in this area, in particular after treatment by surgery and/or radiotherapy. O-2-fluoro-(18F)-ethyl-L-thyrosine (FET) has been reported not to be taken up by such lesions, and a preliminary study indicated that this may be clinically useful in HNSCC. We performed a prospective study to compare the diagnostic performances of FDG and FET PET/CT in the different settings of HNSCC. Materials and Methods  Twenty-seven patients (20 men and seven women, aged 48–76, among 30 patients included) and 69 suspected cancer sites are now evaluable on basis of postsurgical histology and/or follow-up greater than 6 months; 15 patients were referred for initial staging and 12 during posttherapy follow-up, a recurrence being suspected in eight of them. FDG and FET PET/CT were performed on two different days, the patient fasting for 6 h, 1 h after injection of 5 MBq/kg of body mass of each radiopharmaceutical. Both PET/CT examinations were blind read more than 6 months after the end of inclusions in a random order for each tracer and with a time interval greater than 1 month between FDG and FET PET/CT blind readings. Results  Overall diagnostic performances, derived from blind reading: FDG PET/CT on a per patient basis: sensitivity 100%, specificity 71%, accuracy 93%; FDG PET/CT on a per site basis: sensitivity 95%, specificity 63%, accuracy 83%; FET PET/CT on a per patient basis: sensitivity 70%, specificity 100%, accuracy 78%; FET PET/CT on a per site basis: sensitivity 64%, specificity 100%, accuracy 78%. At site level, sensitivity was significantly greater with FDG (p < 0.02) and specificity with FET (p < 0.01). The statistical level of significance was not reached at patient level. Conclusion  Although its good specificity was confirmed, FET did not appear to be suited as a first-line PET tracer in HNSCC imaging and cannot replace FDG for staging due to insufficient sensitivity. However, it was useful in a few selected cases to favor a wait and see attitude when a FDG+ FET− focus was discovered in patients referred for systematic FDG PET during follow-up. In contrast, second primary cancers should not be ruled out if FDG was clearly positive in the lungs or the digestive tract.     

Therapy response monitoring of the early effects of a new BRAF inhibitor on melanoma xenograft in mice: evaluation of 18F‐FDG‐PET and 18F‐FLT‐PET

Inhibition of the V600E mutated BRAF kinase gene (BRAF^V600E) is an important and effective approach to treating melanomas. A new specific small molecule inhibitor of BRAF^V600E, PLX3603, showed potent melanoma growth‐inhibiting characteristics in preclinical studies and is currently under clinical investigation. In this study we investigated the feasibility of ¹⁸F‐FDG and ¹⁸F‐FLT‐PET to monitor the early effects of the BRAF^V600E inhibitor in mice with melanoma xenografts. SCID/beige mice with subcutaneous (s.c.) A375 melanoma xenografts, expressing BRAF^V600E, received the BRAF^V600E inhibitor twice daily orally (0, 25, 50 and 75 mg/kg). At 1, 3 and 7 days after start of therapy, the uptake of ¹⁸F‐FDG and ¹⁸F‐FLT in the tumor and normal tissues was determined in ex vivo tissue samples. Serial ¹⁸F‐FDG and ¹⁸F‐FLT‐PET scans were acquired of animals at 1 day before and 1, 3 and 7 days after start of treatment with 75 mg/kg BRAF^V600E inhibitor. A dose‐dependent decrease in ¹⁸F‐FDG uptake in the A375 tumors was observed by ex vivo biodistribution analysis. Administration of 75 mg/kg BRAF inhibitor for 1, 3 and 7 days resulted in a significantly decreased ¹⁸F‐FDG uptake in A375 tumors (41, 35 and 51%, respectively). ¹⁸F‐FLT uptake in the A375 tumors was low at baseline and no significant changes in ¹⁸F‐FLT uptake were observed at any of the doses administered. These effects were corroborated by serial in vivo ¹⁸F‐FDG and ¹⁸F‐FLT‐PET imaging. These data demonstrate that ¹⁸F‐FDG‐PET can be used as an imaging biomarker to noninvasively evaluate the early effects of PLX3603. Copyright © 2014 John Wiley & Sons, Ltd.     

Dual‐modality in vivo monitoring of subventricular zone stem cell migration and metabolism

Rat subventricular zone (SVZ) stem cells were labeled with superparamagnetic iron oxide particles (SPIO) to follow their fate and migratory potential with magnetic resonance imaging (MRI) and positron emission tomography (PET). Labeled cells were transplanted into either the right rostral migratory stream (RMS) or striatum of normal adult Sprague–Dawley rats and serially followed for 3 months. Minimal migration of the cells implanted into the striatum was observed after 3 weeks whereas SVZ cells implanted into the RMS migrated toward the olfactory bulb at 1 week post‐transplantation. PET studies of glucose metabolism using ¹⁸F‐FDG demonstrated enhanced glucose utilization in the striatum of transplanted animals. PET studies conducted 3 months after transplantation showed elevated accumulation of ¹¹C‐raclopride (dopamine receptor type 2) and ¹¹C‐CFT (dopamine transporter) binding in the striatal grafts. Implanted SVZ cells did not induce significant inflammation as identified by PET using ¹¹C‐PK11195, a ligand detecting activated microglia. Histological analysis identified viable SPIO‐labeled cells (some of which were nestin‐positive) 7 weeks post‐transplantation, suggesting a prolonged presence of undifferentiated neural stem cells within transplants. In addition, double immunostaining for neuronal and astrocytic markers (NeuN and GFAP) indicated that differentiation into neuronal and astrocytic phenotypes also occurred. Thus, combining MRI and PET enables monitoring of cell migration and metabolism non‐invasively in vivo for extended periods of time. Copyright © 2007 John Wiley & Sons, Ltd.     

Comparison of Hypermetabolic and Hypoxic Volumes Delineated on [18F]FDG and [18F]Fluoromisonidazole PET/CT in Non-small-cell Lung Cancer Patients

Purpose

The high rates of failure in the radiotherapy target volume suggest that patients with stage II or III non-small-cell lung cancer (NSCLC) should receive an increased total dose of radiotherapy. 2-Deoxy-2-[¹⁸F]fluoro-d-glucose ([¹⁸F]FDG) and [¹⁸F]fluoromisonidazole ([¹⁸F]FMISO) (hypoxia) uptake on pre-radiotherapy positron emission tomography (PET)/X-ray computed tomography (CT) have been independently reported to identify intratumor subvolumes at higher risk of relapse after radiotherapy. We have compared the [¹⁸F]FDG and [¹⁸F]FMISO volumes defined by PET/CT in NSCLC patients included in a prospective study.

Procedures

Thirty-four patients with non-resectable lung cancer underwent [¹⁸F]FDG and [¹⁸F]FMISO PET/CT before (pre-RT) and during radiotherapy (around 42 Gy, per-RT). The criteria were to delineate 40 % and 90 % SUVmax thresholds on [¹⁸F]FDG PET/CT (metabolic volumes), and SUV >?1.4 on pre-RT [¹⁸F]FMISO PET/CT (hypoxic volume). The functional volumes were delineated within the tumor volume as defined on co-registered CTs.

Results

The mean pre-RT and per-RT [¹⁸F]FDG volumes were not statistically different (30.4 cc vs 22.2; P?=?0.12). The mean pre-RT SUVmax [¹⁸F]FDG was higher than per-RT SUVmax (12.7 vs 6.5; P?<?0.0001). The mean [¹⁸F]FMISO SUVmax and volumes were 2.7 and 1.37 cc, respectively. Volume-based analysis showed good overlap between [¹⁸F]FDG and [¹⁸F]FMISO for all methods of segmentation but a poor correlation for Jaccard or Dice Indices (DI). The DI maximum was 0.45 for a threshold at 40 or 50 %.

Conclusion

The correlation between [¹⁸F]FDG and [¹⁸F]FMISO uptake is low in NSCLC, making it possible to envisage different management strategies as the studies in progress show.

     

Applying Amide Proton Transfer MR Imaging to Hybrid Brain PET/MR: Concordance with Gadolinium Enhancement and Added Value to [<Superscript>18</Superscript>F]FDG PET

Purpose

The purpose of this study is to evaluate the diagnostic concordance and metric correlations of amide proton transfer (APT) imaging with gadolinium-enhanced magnetic resonance imaging (MRI) and 2-deoxy-2-[¹⁸F-]fluoro-D-glucose ([¹⁸F]FDG) positron emission tomography (PET), using hybrid brain PET/MRI.

Procedures

Twenty-one subjects underwent brain gadolinium-enhanced [¹⁸F]FDG PET/MRI prospectively. Imaging accuracy was compared between unenhanced MRI, MRI with enhancement, APT-weighted (APTW) images, and PET based on six diagnostic criteria. Among tumors, the McNemar test was further used for concordance assessment between gadolinium-enhanced imaging, APT imaging, and [¹⁸F]FDG PET. As well, the relation of metrics between APT imaging and PET was analyzed by the Pearson correlation analysis.

Results

APT imaging and gadolinium-enhanced MRI showed superior and similar diagnostic accuracy. APTW signal intensity and gadolinium enhancement were concordant in 19 tumors (100 %), while high [¹⁸F]FDG avidity was shown in only 12 (63.2 %). For the metrics from APT imaging and PET, there was significant correlation for 13 hypermetabolic tumors (P < 0.05) and no correlation for the remaining six [¹⁸F]FDG-avid tumors.

Conclusions

APT imaging can be used to increase diagnostic accuracy with no need to administer gadolinium chelates. APT imaging may provide an added value to [¹⁸F]FDG PET in the evaluation of tumor metabolic activity during brain PET/MR studies.

     

PET imaging of prostate tumors with 18F‐Al‐NOTA‐MATBBN

Overexpression of the gastrin‐releasing peptide receptor (GRPR) in prostate cancer provides a promising target for detection the disease. MATBBN is a new bombesin analog originating from the GRPR antagonists with a hydrophilic linker. In this study NOTA‐conjugated MATBBN was labeled by the Al¹⁸F method and the potential of ¹⁸F‐Al‐NOTA‐MATBBN for prostate tumor PET imaging was also evaluated. NOTA‐MATBBN was radiolabeled with ¹⁸F using Al¹⁸F complexes. Partition coefficient, in vitro stability and GRPR binding affinity were also determined. PET studies were performed with ¹⁸F‐Al‐NOTA‐MATBBN in PC‐3 tumor‐bearing mice. ¹⁸F‐Al‐NOTA‐MATBBN can be produced within 30 min with a decay‐corrected yield of 62.5 ± 2.1% and a radiochemical purity of >98%. The logP octanol–water value for the Al¹⁸F‐labeled BBN analog was ?2.40 ± 0.07 and the radiotracer was stable in phosphate‐buffered saline and human serum for 2 h. The IC₅₀ values of displacement for the ¹⁸F‐Al‐NOTA‐MATBBN with MATBBN was 126.9 ± 2.75 nm . The PC‐3 tumors were clearly visible with high contrast after injection of the labeled peptide. At 60 min post‐injection, the tumor uptakes for ¹⁸F‐Al‐NOTA‐MATBBN and ¹⁸F‐FDG were 4.59 ± 0.43 and 1.98 ± 0.35% injected dose/g, and tumor to muscle uptake radios for two tracers were 6.77 ± 1.10 and 1.78 ± 0.32, respectively. Dynamic PET revealed that ¹⁸F‐Al‐NOTA‐MATBBN was excreted mainly through the kidneys. GRPR‐binding specificity was also demonstrated by reduced tumor uptake of ¹⁸F‐Al‐NOTA‐MATBBN after coinjection with excess unlabeled MATBBN peptide at 1 h post‐injection. NOTA‐ MATBBN could be labeled rapidly with ¹⁸F using one step method. ¹⁸F‐Al‐NOTA‐MATBBN may be a promising PET imaging agent for prostate cancer. Copyright © 2014 John Wiley & Sons, Ltd.     

18F-脱氧葡萄糖-正电子发射型体层摄影术显像诊断鼻咽癌放疗后残留病灶的价值

目的：探讨^18F-脱氧葡萄糖（FDG）-正电子发射型体层摄影水（PET）在鼻咽癌放疗后残留病灶中的诊断价值。方法：分析2003年1月至2005年12月间在本院治疗的36例鼻咽癌患者。所有患者放疗后行PET或MRI／CT检查，依据病理或随访结果对残留病灶进行定性评价。结果：36例患者中，PET显示异常浓聚、诊断为病灶残留的有23例，而MRI／CT为18例，PET诊断病灶残留的灵敏度和假阳性率分别为91．5％和8．7％，而MRI／CT分别为77．3％和22、2％。结论：^18F-FDG-PET对鼻咽癌放疗后残留病灶的判断较MRI／CT准确。     

18F-FDG PET/CT在肾脏肿瘤诊疗中的应用

目的评价18F-FDG PET/CT在肾脏肿瘤诊断和治疗中的价值。方法对30例CT或MRI确诊或怀疑肾脏肿瘤的患者行18F-FDG PET/CT显像,22例患者行延迟显像。所有肾脏肿瘤均经手术或穿刺活检后病理确诊。评价18F-FDG PET/CT对患者治疗方案的影响。结果 30例中,肾细胞癌(RCC)24例,肾神经内分泌肿瘤1例,淋巴瘤3例,肺癌肾转移1例,肾脏炎性病变1例。PET/CT诊断肾脏肿瘤的灵敏度为89.66%(26/29),特异度为100%(1/1),准确率为90.00%(27/30),阳性预测值为100%(26/26),阴性预测值为25.00%(1/4)。PET/CT检出肾癌伴肾门淋巴结转移2例,远处转移5例。8例(RCC 4例、肾淋巴瘤3例及肾转移癌1例)接受PET/CT后治疗方案发生改变。显像阳性肾癌患者Fuhrman分级高于阴性患者(P<0.05),显像阳性肾癌平均直径大于阴性者(P<0.05)。22例肾癌早期最大标准摄取(SUVmax)值与延迟显像SUVmax值差异无统计学意义(P>0.05)。结论 18F-FDG PET/CT可准确显示肾肿瘤患者局部病变及远处转移。对可疑肾淋巴瘤及肾转移瘤患者应行18F-FDG PET/CT显像,以明确分期并寻找原发灶。     

PET在肿瘤影像诊断中与CT、MRI的相互关系——附28例~(18)F FDG PET与CT、MRI结果对照

目的　本文着重探讨１８ＦＦＤＧＰＥＴ与ＣＴ、ＭＲ影像诊断技术在肿瘤临床诊断、手术方案的确定和治疗后随访中的互补作用。方法　对２８ 例临床诊断的恶性肿瘤同期进行１８ＦＦＤＧＰＥＴ、ＣＴ和ＭＲＩ检查,其中２１ 例经手术病理或活检证实;采用双盲法,将ＰＥＴ诊断结果与同期的ＣＴ和／或ＭＲ影像进行比较。结果　本组２７ 例肿瘤中,１８ＦＦＤＧＰＥＴ 显像结果与ＣＴ、ＭＲＩ诊断相符２０ 例（ 占７４％ ）,１８ＦＦＤＧＰＥＴ 显像进一步肯定或明确ＣＴ、ＭＲＩ的结论７ 例（ 占２６％ ）;另１ 例临床、ＣＴ和ＭＲＩ均误诊为乳腺癌术后脑转移病例,经１８ＦＦＤＧＰＥＴ 显示为脑梗塞;ＰＥＴ影像上,恶性肿瘤病灶均表现为局部１８ＦＦＤＧ明显浓聚;ＣＴ和／或ＭＲ 影像上,２０ 例肿瘤有局部神经、血管和重要脏器等的侵犯,以及肿瘤瘤内出血、坏死和瘤周水肿等,但ＰＥＴ 均不能显示。结论　虽然１８ＦＦＤＧＰＥＴ 对恶性肿瘤的定性诊断具有较高的准确性和特异性,但是１８ＦＦＤＧＰＥＴ仍不能取代ＣＴ 和ＭＲＩ在肿瘤诊断中的作用;最好的方法是结合ＰＥＴ、ＣＴ 和ＭＲＩ多种影像结果分析,才能为临床提供有关肿瘤病变的解剖细节和功能异常改变的综合信息。     

Utility of [<Superscript>18</Superscript>F]FSPG PET to Image Hepatocellular Carcinoma: First Clinical Evaluation in a US Population

Purpose

Non-invasive imaging is central to hepatocellular carcinoma (HCC) diagnosis; however, conventional modalities are limited by smaller tumors and other chronic diseases that are often present in patients with HCC, such as cirrhosis. This pilot study evaluated the feasibility of (4S)-4-(3-[¹⁸F]fluoropropyl)-L-glutamic acid ([¹⁸F]FSPG) positron emission tomography (PET)/X-ray computed tomography (CT) to image HCC. [¹⁸F]FSPG PET/CT was compared to standard-of-care (SOC) magnetic resonance imaging (MRI) and CT, and [¹¹C]acetate PET/CT, commonly used in this setting. We report the largest cohort of HCC patients imaged to date with [¹⁸F]FSPG PET/CT and present the first comparison to [¹¹C]acetate PET/CT and SOC imaging. This study represents the first in a US HCC population, which is distinguished by different underlying comorbidities than non-US populations.

Procedures

x_C? transporter RNA and protein levels were evaluated in HCC and matched liver samples from The Cancer Genome Atlas (n = 16) and a tissue microarray (n = 83). Eleven HCC patients who underwent prior MRI or CT scans were imaged by [¹⁸F]FSPG PET/CT, with seven patients also imaged with [¹¹C]acetate PET/CT.

Results

x_C? transporter RNA and protein levels were elevated in HCC samples compared to background liver. Over 50 % of low-grade HCCs and ~70 % of high-grade tumors exceeded background liver protein expression. [¹⁸F]FSPG PET/CT demonstrated a detection rate of 75 %. [¹⁸F]FSPG PET/CT also identified an HCC devoid of typical MRI enhancement pattern. Patients scanned with [¹⁸F]FSPG and [¹¹C]acetate PET/CT exhibited a 90 and 70 % detection rate, respectively. In dually positive tumors, [¹⁸F]FSPG accumulation consistently resulted in significantly greater tumor-to-liver background ratios compared with [¹¹C]acetate PET/CT.

Conclusions

[¹⁸F]FSPG PET/CT is a promising modality for HCC imaging, and larger studies are warranted to examine [¹⁸F]FSPG PET/CT impact on diagnosis and management of HCC. [¹⁸F]FSPG PET/CT may also be useful for phenotyping HCC tumor metabolism as part of precision cancer medicine.

     

Improvements in PET Image Quality in Time of Flight (TOF) Simultaneous PET/MRI

Purpose

An integrated positron emission tomography (PET)/magnetic resonance imaging (MRI) scanner with time of flight (TOF) technology is now available for clinical use. The aim of this study is to evaluate the potential of TOF PET in PET/MRI to reduce artifacts in PET images when compared to non-TOF PET/MRI, TOF PET/X-ray computed tomography (CT), and non-TOF PET/CT.

Procedures

All patients underwent a single 2-deoxy-2-[¹⁸F]fluoro-d-glucose ([¹⁸F]FDG) injection, followed first by PET/CT, and subsequently by PET/MRI. PET/CT exams were requested as standard-of-care for oncological indications. Using the PET acquisitions datasets, 4 series of images (TOF PET/CT, non-TOF PET/CT, TOF PET/MRI, and non-TOF PET/MRI) were reconstructed. These image series were visually evaluated for: (1) dental metal artifacts, (2) breathing artifacts, and (3) pelvic artifacts due to scatter correction errors from high bladder [¹⁸F]FDG concentration. PET image quality was assessed by a 3-point scale (1—clinically significant artifact, 2—non clinically significant artifact, and 3—no artifact).

Results

Twenty-five patients (mean?±?SD age: 56?±?13 years old; female: 10, male: 15) were enrolled. TOF PET/MRI, non-TOF PET/MRI, TOF PET/CT, and non-TOF PET/CT scores 2.8, 2.5, 2.4, and 2.3, respectively for the presence of dental artifacts, 2.8, 2.5, 2.2, and 1.9, respectively, for the presence of breathing artifacts, and 2.7, 1.7, 2.0, and 1.3, respectively, for the presence of pelvic artifacts TOF PET/MRI images showed the highest image quality scores among the 4 datasets of PET images.

Conclusion

The superior timing resolution and resulting TOF capability of the new PET/MRI scanner improved PET image quality in this cohort by reducing artifacts compared to non-TOF PET/MRI, TOF PET/CT, and non-TOF PET/CT.

     

^18F—FDGPET／CT在弥漫性大B细胞淋巴瘤诊治中临床应用

目的探讨^18FFDGPET／CT对弥漫性大B细胞淋巴瘤（DLBCL）诊断、分期和治疗后评估的临床意义。方法对48例初诊DLBCL病人进行临床评价及^18F-FDGPET／CT检查。结果^18F-FDGPET／CT对初诊DLBCL病人的诊断灵敏度为98％（47／48）;^18F-FDGPET／CT分期与临床分期的一致性为92％（44／48）,4例病人的分期结果不一致。^18F-FDGPET／CT监测复发或微小残留病的敏感率高于临床评价。结论^18F—FDGPET／CT对DLBCL的诊断、分期和疗效评估具有重要价值。     

Multimodal imaging of tumor response to sorafenib combined with radiation therapy: comparison between diffusion‐weighted MRI,choline spectroscopy and 18F‐FLT PET imaging

The purpose of this study was to determine the value of different imaging modalities, that is, magnetic resonance imaging/spectroscopy (MRI/MRS) and positron emission tomography (PET), to assess early tumor response to sorafenib with or without radiotherapy. Diffusion‐weighted (DW)‐MRI, choline ¹H MRS at 11.7 T, and ¹⁸F‐FLT PET imaging were used to image fibrosarcoma (FSaII) tumor‐bearing mice over time. The imaging markers were compared with apoptosis cell death and cell proliferation measurements assessed by histology. Anti‐proliferative effects of sorafenib were evidenced by ¹H MRS and ¹⁸F‐FLT PET after 2 days of treatment with sorafenib, with no additional effect of the combination with radiation therapy, results that are in agreement with Ki67 staining. Apparent diffusion coefficient calculated using DW‐MRI was not modified after 2 days of treatment with sorafenib, but showed significant increase 24 h after 2 days of sorafenib treatment combined with consecutive irradiation. The three imaging markers were able to show early tumor response as soon as 24 h after treatment initiation, with choline MRS and ¹⁸F‐FLT being sensitive to sorafenib in monotherapy as well as in combined therapy with irradiation, whereas DW‐MRI was only sensitive to the combination of sorafenib with radiotherapy. Copyright © 2013 John Wiley & Sons, Ltd.     

中枢神经系统疾病的18F-FDG PET显像——附17例PET与CT、MRI和EEG对照

目的 地＾１８Ｆ－ＦＤＧＰＥＴ在中枢神经系统疾病临床诊断中应用的初步体会作一介绍。方法 ＾１８Ｆ－ＦＤＧＰＥＴ检查共计１７例,所有患者静脉注射＾１８Ｆ－脱氧葡萄糖（ＦＤＧ）１０ｍＣｉ后４０分钟进行脑＾１８Ｆ－ＦＤＧ正电子发射断层显像（ＰＥＴ）。其结果与同期的ＣＴ、ＭＲＩ、ＥＥＧ结果进行比较。结果 在１０例癫痫发作间歇期病人中,４０％的病例＾１８Ｆ－ＦＤＧＰＥＴ显示病侧局部脑叶葡萄代谢正常、脑梗塞、     

Giant cell arteritis on 18F‐FDG PET/CT

Purpose: We present a case of incidentally noted giant cell arteritis in a patient undergoing 18F‐fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT imaging. The patient was originally referred to PET/CT for staging of his renal transitional cell carcinoma. Methods: The patient was injected intravenously with 370 MBq of 18F‐FDG. After a 60 min uptake period, PET/CT imaging was performed from the skull base to the mid thighs. Results: A small para‐aortic node in the region of the surgical bed showed increased tracer uptake of concern for malignancy. In addition, there were several non‐calcified pulmonary nodules present, also concerning for malignancy. Incidentally noted was diffusely increased tracer uptake throughout the aorta and a thickened aortic wall on CT images. Diffuse tracer uptake was also present in the proximal branches of the aorta, including the carotid, iliac, femoral, and subclavian arteries. The patient had biopsy proven giant cell arteritis. Conclusion: Increased 18F‐FDG uptake by the aorta on PET/CT imaging is an abnormal finding that prompts a more thorough assessment for malignancy, and also can indentify important co‐morbidities in cancer patients. Evaluation of aortic uptake should be a routine practice in the interpretation of 18F‐FDG PET/CT scans.     

2-Deoxy-2-[F-18]fluoro-<Emphasis Type="SmallCaps">d</Emphasis>-glucose Positron Emission Tomography/Computed Tomography in the Management of Melanoma

Objectives 2-Deoxy-2-[F-18]fluoro-d-glucose (FDG)-positron emission tomography (PET)/computed tomography (CT) is widely available as a powerful imaging modality, combining the ability to detect active metabolic processes and their morphologic features in a single exam. The role of FDG-PET is proven in a variety of cancers, including melanoma, but the estimates of sensitivity and specificity are based in the majority of the published studies on dedicated PET, not PET/CT. Therefore, we were prompted to review our experience with FDG-PET/CT in the management of melanoma. Methods This is a retrospective study on 106 patients with melanoma (20–87 years old; average: 56.8 ± 15.9), who had whole-body FDG-PET/CT at our institution from January 2003 to June 2005. Thirty-eight patients (35.9%) were women and 68 patients (64.1%) were men. Reinterpretation of the imaging studies for accuracy and data analysis from medical records were performed. Results All patients had the study for disease restaging. The primary tumor depth (Breslow’s thickness) at initial diagnosis was available for 76 patients (71.7%) and ranged from 0.4 to 25 mm (average: 3.56 mm). The anatomic level of invasion in the skin (Clark’s level) was determined for 70 patients (66%): 3, level II; 13, level III; 43, level IV; 11, level V. The administered dose of ¹⁸F FDG ranged from 9.8 to 21.6 mCi (average: 15.4 ± 1.8 mCi). FDG-PET/CT had a sensitivity of 89.3% [95% confidence interval (CI): 78.5–95] and a specificity of 88% (95% CI: 76.2–94.4) for melanoma detection. Conclusion This study confirms the good results of FDG-PET/CT for residual/recurrent melanoma detection, as well as for distant metastases localization. PET/CT should be an integral part in evaluation of patients with high-risk melanoma, prior to selection of the most appropriate therapy.