腺癌性孤立性肺结节的^18F—FDG PET／CT表现

目的探讨腺癌性孤立性肺结节（ASPN）的^18F—FDG PET／CT显像特点。方法回顾分析35例ASPN的^18F-FDG PET／CT显像形态学和代谢特点,计算SUVmax,以公式[（延迟显像SUVmax-早期显像SUVmax）／早期SUVmax×100％]计算△SUVmax。以SPSS11．5软件对数据分别行t检验、方差分析和Fisher确切概率法检验。结果（1）42．86％（15／35）ASPN呈典型的癌性肺结节表现（结节状FDG摄取增高）,另有57．14％（20／35）ASPN FDG摄取呈片状、云雾状、肉眼无法辨认;结节状、云雾状、片状、肉眼无法辨认ASPN的SUVmax大小顺序递减,不同FDG摄取形态的ASPN早期和晚期SUVmax差异均有统计学意义,F=30．696和24．758,P均〈0．001。（2）54．29％（19／35）ASPN SUVmax≥2．5,45．71％（16／35）ASPN SUVmax〈2．5。（3）68．57％（24／35）ASPN呈实性密度结节,31．43％（11／35）ASPN呈“磨玻璃”密度结节;早期SUVmax分别为4．54±2．69、1．30±0．87,t=-5．234,P〈0．001。（4）延迟显像ASPN的SUVmax为422±3．52,高于早期显像的3．49±2．72（t=-4021,P〈0．1301）;延迟显像SUVmax是否增高与早期显像SUVmax的高低相关：94．74％（18／19）SUVmax≥2．5ASPN的△SUVmax为正值,仅56．25％（9／16）SUVmax〈2．5ASPN的△SUVmax为正值,P=0．013。（5）高分化ASPN SUVmax为1．70±1．51,低于中低分化ASPN的4．91±2．69,t=-3．951,P〈0．001,且△SUVmax〉0的比例（10／17）也低于中低分化ASPN（13／14）,P=0．045。结论ASPNFDG摄取形态、代谢活性差异大,SUVmax〈2．5ASPN比例较高,△SUVmax对这类结节良恶性的鉴别有一定帮助。     

18F-FDG PET/CT and contrast-enhanced CT findings of pulmonary cryptococcosis

PurposePulmonary cryptococcosis is an uncommon cause of pulmonary nodules in non-AIDS patients. This study reports the ¹⁸F-fluorodeoxyglucose-positron emission tomography (¹⁸F-FDG PET/CT) and contrast-enhanced CT (CE-CT) findings of 42 patients with pulmonary cryptococcosis.Materials and methodsA retrospective review of the ¹⁸F-FDG PET/CT and CE-CT findings of 42 patients with histologically proven pulmonary cryptococcosis was conducted. All patients underwent PET/CT and CE-CT in the same session. The CT diagnosis was based on the location, morphological features, and enhancement of lesions. The PET/CT findings were recorded, and clinical data and surgical and histopathological findings were collected.ResultsThe results of the PET scans revealed that 37 (88%) of 42 patients showed higher FDG uptake, and 5 (12%) patients demonstrated lower FDG uptake than the mediastinal blood pool. The maximum standardized uptake value (SUV) of pulmonary cryptococcosis ranged from 1.4 to 13.0 (average: 5.7 ± 3.3, median 4.9). A single nodular pattern was the most prevalent pattern observed and was found in 29 (69%) patients. This pattern was followed by scattered nodular (n = 4, 10%), clustered nodular (n = 3, 7%), mass-like (n = 3, 7%), and bronchopneumonic (n = 3, 7%) patterns. The most frequent pattern of immunocompetent patients was the single nodular pattern (29 of 33, 88%). Immunocompromised patients most frequently pattern exhibited mass-like (3 of 9, 33%) and bronchopneumonic (3 of 9, 33%) patterns.ConclusionPulmonary cryptococcosis most commonly appears as single nodules in immunocompetent patients. Mass-like and bronchopneumonic patterns were common in immunocompromised patients. In 88% of patients, lung lesions showed high FDG uptake, thus mimicking a possible malignant condition.     

Evaluation of 18F-FDG uptake and arterial wall calcifications using 18F-FDG PET/CT.

Glucose metabolic activity expressed as (18)F-FDG uptake may be increased in active atherosclerotic plaque. Calcium depositions are often increased in mature atherosclerotic plaque. The purpose of the present study was to assess the patterns of vascular-wall (18)F-FDG uptake and CT calcifications using combined PET/CT. METHODS: One hundred twenty-two consecutive patients over the age of 50 (47 women and 75 men; mean age, 66 +/- 9 y) undergoing whole-body (18)F-FDG PET/CT for tumor assessment were retrospectively evaluated. PET, CT, and PET/CT slices were generated for review. Abnormal vascular findings in major arteries in the chest and abdomen were categorized as PET positive (PET+), PET negative (PET-), CT positive (CT+), or CT negative (CT-). The topographic relationship between increased vascular-wall (18)F-FDG uptake on PET and the presence of calcifications on CT was assessed on PET/CT fused images, with abnormal sites further classified as PET+/CT+, PET+/CT-, or PET-/CT+. The presence of CT calcifications and increased vascular-wall (18)F-FDG uptake was correlated with age, sex, presence of cardiovascular risk factors, and cardiovascular disease. RESULTS: Abnormal findings were identified at 349 sites. CT calcifications (CT+) were observed at 320 sites (92%) of 100 patients (82%), more commonly in men (P < 0.03), in older patients (P < 0.0001), in patients with hypertension (P < 0.003) or hyperlipidemia (P < 0.04), and in smokers (P < 0.008). Increased vascular-wall (18)F-FDG uptake (PET+) was observed at 52 sites (15%) of 38 patients (31%), more commonly in men (P < 0.02), in older patients (P < 0.0001), and in patients with hypertension (P < 0.02), and was borderline in patients with cardiovascular disease (P = 0.057). PET+ and CT+ findings correlated in 12 patients, a PET+/CT- pattern was found in 18 patients, and 8 patients had increased vascular-wall (18)F-FDG uptake in sites with and without calcifications (PET+/CT+, CT-). Twenty-two patients (18%) had a PET-/CT- pattern. CONCLUSION: Hybrid PET/CT can be used to identify and to correctly localize vascular-wall (18)F-FDG activity. Increased vascular-wall (18)F-FDG activity was found in 15% of sites and CT calcifications were noted in 92% of sites, with congruent findings in 7%. The clinical significance of the relationship between vascular-wall (18)F-FDG uptake and CT calcifications needs to be assessed by further prospective studies with long-term follow up.     

血糖水平对18F-FDG PET/CT图像质量的影响

目的 研究血糖水平对18F-脱氧葡萄糖(FDG) PET/CT图像质量的影响.方法 80例行体格检查或评价肿瘤性质的受检者,按空腹血糖水平分为9组(组间距为1mmol/L),第1组为血糖正常组,即血糖＜6.0mmol/L(10例);第2～9组血糖水平高于正常,分别为6.0～6.9mmol/L(11例),7.0～7.9mmol/L(13例),8.0～8.9mmol/L(11例),9.0～9.9mmol/L(11例),10.0～10.9mmol/L(8例),11.0～11.9mmol/L(6例),12.0～12.9mmol/L(5例),≥13.0mmol/L(5例).受检者做完PET/CT检查后,图像质量由2位有经验的医师独立判断.同时根据肝不同层面的标准摄取值(SUV)最大值(SUVmax)及SUV平均值(SUVavg)分别计算肝图像噪声.采用SPSS 12.0软件进行统计学处理.结果 (1)9组之间图像质量评分、肝噪声差异有统计学意义(P均＜0.05).将第2～9组图像质量评分、肝噪声分别与第1组进行比较,第2～7组与第1组差异无统计学意义(P均＞0.05);第8,9组与第1组比较差异有统计学意义(P均＜0.05),且评分低于第1组.(2)血糖水平与图像质量评分呈负相关(r=-0.52,P＜0.05);血糖水平与肝噪声呈正相关(SUVmax、SUVavgr值分别为0.33和0.60,P均＜0.05);SUVavg所算噪声与血糖水平的相关性优于SUVmax.结论 图像质量随血糖水平的升高而下降,血糖＜12.0mmol/L时与血糖正常者PET/CT图像质量差异无统计学意义,但当血糖水平≥12.0mmol/L时图像质量将显著下降.     

18F-FDG PET/CT伪影和不常见生理性摄取分析

目的 探讨^18F-脱氧葡萄糖（FDG）PET/CT显像各种伪影的影像学表现及其产生的原理.方法 回顾性分析^18F-FDG PET/CT检查患者的图像,根据伪影产生的原因进行分类,同时对临床不常见的生理性摄取进行分析.结果 伪影分为自身因素和设备技术因素伪影,自身因素所致伪影中以呼吸运动伪影和高密度物质伪影最为常见;设备因素伪影中以截断伪影、注射点外漏和放射性污染最为常见.不常见的生理性摄取包括：子宫内膜摄取、乳腺摄取和脂肪摄取.结论 PET显像伪影影像学表现可分为“热区”或“冷区”.不常见的生理性摄取主要表现为“热区”.伪影产生原因中以CT应用于PET显像后物理学因素多见.不常见的生理性摄取与检查技术有关.     

18F-FDG PET/CT和同机CT增强扫描对肺硬化性血管瘤的诊断价值

目的 探讨肺硬化性血管瘤(PSH)的18F-FDG PET/CT显像和CT增强扫描特征及2种方法对该病的诊断价值.方法 回顾性分析2007年6月至2011年6月间,经病理证实为PSH、有同机18 F-FDG PET/CT双时相(早期、延迟)显像、病灶层面高分辨率(HR) CT扫描及多期增强CT扫描资料的5例患者,其中女4例,男1例,发病年龄39 ～66(平均51.6)岁.对PET/CT早期、延迟显像图及滞留指数,CT扫描的增强净增值、峰值下降时间及“边缘血管征”等进行综合分析.结果 PSH在双时相18 F-FDG PET/CT显像上表现为斑片样FDG代谢增高,早期显像SUVmax为3.3±1.1,延迟显像SUVmax增高或降低,平均为3.4±1.4,平均滞留指数为(2.1±20.8)％;HRCT可表现为边界清晰的圆形或类圆形结节或肿块,部分可见“空气新月征”,少数病灶内可见钙化点;多期CT增强扫描显示病灶呈中～高度强化(增强净增值为35 ～ 59 HU),增强后峰值下降(峰值下降时间为140～260 s),5例病例均可见1～4条数量不等的“边缘血管征”.结论 PSH 18F-FDG PET/CT显像的肿块或结节的斑片样高代谢表现提示其可能为良性病灶;结合病灶层面的诊断性CT扫描(包括增强)表现,可进一步明确PSH的诊断.     

^18F-FDG PET／CT 结合 HRCT 对肺微浸润性腺癌的诊断价值

目的：^18 F-FDG PET/CT结合 HRCT 对肺微浸润性腺癌（minimally invasive adenocarcinoma ,MIA）的诊断价值。方法搜集经手术病理证实28例肺 MIA 患者的^18 F-FDG PET/CT 及 HRCT 影像资料,患者均先行^18 F-FDG PET/CT显像,后行HRCT扫描检查,分析其形态学表现及放射性分布,同时测量其SUVmax值,分析PET/CT、HRCT、PET/CT结合 HRCT三者的准确率。结果28例患者中,18 F-FDG PET 显像有19例出现高于肺本底的局灶性异常放射性摄取增高影,以SUVmax＞2．5为标准,诊断MIA的灵敏度为32．1％（9/28）。HRCT 病灶显示磨玻璃密度结节27例（96．4％）,其中单纯磨玻璃密度结节10例,混杂磨玻璃密度结节17例,单纯实性密度结节1例;病灶出现边缘分叶征18例（64．3％）,毛刺征20例（71．4％）,空泡征或支气管充气征21例（75％）,胸膜凹陷征12例（42．9％）,血管集束征10例（35．7％）,圆形结节征13例（46．4％）。PET/CT、HRCT、PET/CT结合 HRCT 三者的准确率分别为71．4％、82.1％和96．4％。结论^18 F-FDG PET/CT诊断MIA易出现假阴性,PET/CT结合HRCT有利于提高诊断准确率。     

18F-FDG PET/CT显像对小肠腺癌的诊断价值

目的 探讨18F-FDG PET/CT全身显像对小肠腺癌(SIA)的诊断价值.方法 回顾29例SIA(男17例,女12例)、21例小肠淋巴瘤(SIL;男15例,女6例)及10例小肠结核(SIT;男4例,女6例)的18F-FDG PET/CT显像资料,采用目测法和半定量方法(SUVmax)分析3种疾病PET/CT显像特点.计量资料差异比较用单因素方差分析,率的比较行x2检验.结果 (1) PET/CT图像上SIA多表现为小肠局部团块状、结节状高代谢灶,典型的SIL为小肠局部环形异常放射性浓聚灶,SIT多呈结节状、条状高代谢灶、病灶呈“跳跃性”分布;SIA的SUVmax为8.44±3.82,低于SIL(11.54±4.02; F=86.96,t=2.77,均P＜0.01),与SIT的8.61±2.99差异无统计学意义(t=0.11,P＞0.05).(2)SIA、SIL和SIT的灶周淋巴结肿大检出率分别为72.41％ (21/29)、85.71％(18/21)和70.00％ (7/10) (x2=1.50,P＞0.05);SIA的灶周肿大淋巴结SUVmax为5.59±2.86,明显低于SIL的11.10±5.72(F=56.56,t=3.85,均P＜0.01),与SIT的5.63±3.36差异无统计学意义(t=0.30,P＞0.05).PET/CT显像对SIA的灶周淋巴结肿大检出率明显高于CT(41.38％,12/29;x2=5.69,P＜0.05).(3)55.17％(16/29)的SIA有小肠外转移灶;66.67％(14/21)的SIL有小肠外病灶,以全身多发淋巴结浸润多见;80.00％(8/10)的SIT有腹腔外结核灶;三者小肠外病灶检出率差异无统计学意义(x2=2.13,P＞0.05).(4)29例SIA中15例(51.72％)累及回肠,8例(27.59％)累及空肠,4例(13.79％)空肠回肠同时受累,2例(6.90％)空肠十二指肠同时受累,病灶分布差异有统计学意义(x2=18.16,P＜0.01).(5)29例SIA中单原发癌8例(27.59％),转移性癌14例(48.28％),7例(24.14％)考虑为双原发癌.(6)以病理、诊断性治疗和临床随访结果为标准,18F-FDG PET/CT显像诊断SIA的灵敏度为93.10％(27/29),特异性为80.00％(8/10).结论 18F-FDG PET/CT全身显像可用于SIA的鉴别诊断,可为单原发、多原发及转移性SIA诊断提供依据.     

18F-FDG PET/CT superior to serum CEA in detection of colorectal cancer and its recurrence

The aim of this study was to examine whether positron emission tomography (PET)/computed tomography (CT) can detect more cases of colorectal cancer (CRC) than serum carcinoembryonic antigen (CEA), both at initial staging and during surveillance for recurrence. A retrospective review of 639 CRC patients imaged with PET/CT was performed. PET/CT was superior to serum CEA in detecting CRC, identifying 2.5 times as many CRC at initial staging compared to serum CEA and 1.5 times as many CRC recurrences. The current guideline recommendations of utilizing PET/CT only in the context of a rising serum CEA will miss more than one third of all CRC recurrences.     

Cosmetic-related changes on 18F-FDG PET/CT

We present 4 cases of cosmetic-related changes on 18F-FDG PET/CT. These cases represent post-treatment changes from facial juvederm injection, silicone injection in the chest wall and gluteal areas, paraffin injection in the gluteal region, and liposuction. Recognition of cosmetic-related changes and their appearance on PET and CT will help to avoid potential false-positive interpretations.     

~(18)F-FDGPET/CT棕色脂肪摄取的影像学分析

目的:分析18F-FDG PET/CT检查中棕色脂肪组织(BAT)摄取的规律和特点,以避免不必要的误诊。方法:回顾性分析行PET/CT全身检查的2350例受检者的图像。结果:34例(1.44%)有不同程度BAT摄取,其中恶性肿瘤患者9例(甲状腺癌术后4例)。BAT显影主要在寒冷季节出现,女性比例(2.57%)高于男性(0.76%);特征性表现为对称性分布于肩颈部、锁骨上区、脊柱两旁、纵隔、肾上腺及肾周区的高摄取灶,SUVmax为7.18±4.27。BAT显影部位的数目与摄取的SUVmax呈正相关(r=0.78,P<0.05);5例检查者进行了延迟扫描,延迟后BAT分布、形态无明显变化,SUVmax显著升高(P<0.05)。4例甲状腺癌术后复查病例的BAT摄取不同程度影响了对区域淋巴结的观察。结论:BAT摄取的分布及影像表现具有一定的特征性,显影部位越多,SUVmax越大,延迟扫描后SUVmax显著升高,容易干扰对显影区域病灶的观察。     

18F-FDG PET and PET/CT for detection of pulmonary metastases from musculoskeletal sarcomas

OBJECTIVE: Sarcomas represent a significant therapeutic challenge and their potential for distant pulmonary metastases is well known. [(18)F]Fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) has a role in differentiating sarcomas from benign tumours and assessing the response to therapy in advanced sarcomas. However, PET appears to be less accurate in detection of pulmonary metastases. We were therefore prompted to review our experience with PET and PET/computed tomography (CT) in osseous and soft tissue sarcomas (OSTSs). METHODS: This is a retrospective study (January 1995 to December 2004) of 106 patients with histological diagnosis of OSTS, who had PET and PET/CT at our institution. The group included 52 men and 54 women, aged 12-92 years (average, 45+/-20 years). RESULTS: For all the patients in the analysis, the sensitivity and specificity were 68.3% (95% CI: 53-80.4) and 98.4% (95% CI: 91.8-99.7) for PET, with 95.1% sensitivity (95% CI: 83.8-98.6) and 92.3% specificity (95% CI: 83.2-96.7) for CT. Pulmonary metastases were seen in 40 patients. CT identified 17 lesions larger than 1.0 cm, while PET identified 13 of them (76.5%). CONCLUSIONS: Chest CT is more sensitive than PET in detecting pulmonary metastases from OSTS. A significant portion of known pulmonary metastases greater than 1.0 cm on CT, are PET negative. Sub-centimetre CT lesions should not be considered false positive if inactive on PET. A negative PET scan in the presence of suspicious CT findings in the chest cannot reliably exclude pulmonary metastases from OSTS.     

Influence of reconstruction iterations on 18F-FDG PET/CT standardized uptake values.

The goal of this study was to evaluate the effect on the average standardized uptake value (avgSUV) and maximum standardized uptake value (maxSUV) of changing the number of iterations in the reconstruction process on studies acquired with PET/CT. METHODS: Data from 50 human tumors were acquired on a PET/CT scanner, using the CT portion for attenuation correction. Reconstruction was performed using the 2-dimensional reconstruction method of ordered-subsets expectation maximization (OSEM) with 28 subsets and with 1, 2, 3, 4, 5, 10, 20, and 40 iterations. The standardized uptake value (SUV) of the studies was analyzed by positioning a region of interest tightly around the tumor and reproducing the same area on all same-study iterations for SUV measurements. RESULTS: The differences in mean avgSUV and mean maxSUV were statistically different across different iteration groups. SUV data demonstrated that the avgSUV measurements have the most significant differences between 1 versus 2 iterations and 2 versus 3 iterations. The P values for these comparisons were less then 0.001. For maxSUV, all differences had P values less than 0.001. There also was a systematic increase in the SUVs as the number of iterations increased. The avgSUV increased at early iterations (less than 5), with just 50%-60% increasing after 5 iterations. However, maxSUV increased systematically at early iterations, and this trend continued as the number of iterations increased. CONCLUSION: The OSEM algorithm converges sooner for avgSUV than for maxSUV. The likely reason is that avgSUV depends on low-frequency features that are recovered with fewer iterations. The differences in maxSUV were likely due to noise, which increased with the number of iterative updates, and to increased resolution and recovery of high-frequency features (i.e., tumor heterogeneity) with a larger number of iterations. Factors that determine the quantitative accuracy of iterative reconstruction may have played an additional role. Given the continued change in maxSUV with iterations, great care must be taken in selecting the number of iterative updates when using it to assess tumors and their response to chemotherapy and radiation therapy. Because 2-5 iterations with 8-28 subsets are being used in clinical settings, these data are pertinent when comparing the SUVs of a tumor before and after therapy.