Incidental Focal 18F-FDG Uptake in the Prostate: Clinical Significance and Differential Diagnostic Criteria

Purpose

The extent and intensity of ¹⁸F-FDG uptake in prostate cancer patients are known to be variable, and the clinical significance of focal ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) uptake that is incidentally found on positron emission tomography (PET) has not been established. We investigated the clinical significance of incidental focal prostate uptake of ¹⁸F-FDG on PET/computed tomography (CT) and analyzed differential findings on PET/CT between malignant and benign uptake.

Methods

A total of 14,854 whole-body ¹⁸F-FDG PET/CT scans (4,806 that were conducted during cancer screening and 10,048 that were conducted to evaluate suspected or alleged cancer outside of the prostate) were retrospectively reviewed to determine the presence, location, multiplicity and maximum standardized uptake value (SUVmax) of focal prostate uptake and combined calcification. The final diagnosis determined by serum prostate-specific antigen (PSA) level and biopsy was compared with PET findings.

Results

Incidental focal prostate uptake was observed in 148 of 14,854 scans (1.0 %). Sixty-seven of these 148 subjects who had diagnostic confirmation were selected for further analysis. Prostate cancer was diagnosed in nine of 67 subjects (13.4%). The remaining 58 subjects had no malignancy in the prostate based on normal serum PSA level (n = 53), or elevated serum PSA level with a negative biopsy result (n = 5). While 84.6% (11/13) of malignant uptake was peripherally located in the prostate glands, 60.2% (50/83) of benign uptake was centrally located (p < 0.05). The positive predictive value of peripheral focal uptake for malignancy was 25%. The SUVmax, multiplicity and combined calcification were not significantly different between the two groups.

Conclusion

Although incidental focal ¹⁸F-FDG uptake in the prostate is not common, the incidence of cancer with focal uptake is not low. Therefore, these findings deserve further evaluation. The location of the focal prostate uptake may help with the selection of high-risk prostate cancer patients.     

Significance of Incidental Nasopharyngeal Uptake on 18F-FDG PET/CT: Patterns of Benign/Physiologic Uptake and Differentiation from Malignancy

Purpose

The purpose of this study was to assess the significance of incidental nasopharyngeal uptake on 18F-FDG PET/CT and to identify image patterns useful in the differentiation between benign or physiologic activity and nasopharyngeal carcinoma.

Methods

We retrospectively reviewed medical records of patients with nasopharyngeal uptakes on 18F-FDG PET/CT scans taken between January 2010 and July 2011. Patients with head and neck cancer, other metastatic head and neck lesions, or lymphoma were excluded. Total 177 patients were enrolled (Group A). PET images were reviewed for patterns of nasopharyngeal FDG uptake, presence/absence of cervical lymph node uptake and pattern of cervical node uptake. Diagnostic confirmation was made by pathology or clinical and radiological follow-up for 1 year or longer. Furthermore, initial PET/CT images of 48 patients with nasopharyngeal carcinoma (Group B) were reviewed for comparison with PET/CT images of Group A patients.

Results

All nasopharyngeal uptakes in Group A were confirmed to be benign. Group B showed significantly more intense FDG uptake (SUVmax of Group A 3.9 ± 1.4 vs. Group B 10.4 ± 4.6, p<0.001). and asymmetric nasopharyngeal uptake (asymmetric uptake of Group A 67.8% vs. Group B 89.6%). When SUVmax of 6.0 was used as cut off for detection of malignant nasopharyngeal uptake, the area under the ROC curve was 0.93 (95% confidence interval, 0.88-0.98), with a sensitivity of 88.1% and a specificity of 91.7%. Metastatic nodes in Group B showed higher SUVmax (Group A 2.3 ± 0.6 vs. Group B 7.1 ± 4.0, p<0.001) and larger size (short axis of Group A 5.3 ± 2.0 mm vs. Group B 13.1 ± 4.7 mm, p<0.001) than benign nodes of Group A. The majority of Group B cases demonstrated retropharyngeal lymph node uptake (70.8%), compared to only 2 cases in Group A.

Conclusions

In patients without a history of underlying malignancy involving head and neck, incidental nasopharyngeal uptake on PET/CT does not indicate malignancy. However, if the nasopharyngeal uptake is intense (SUVmax≥6.0) or concomitant retropharyngeal lymph node uptake is present, the possibility of a malignant condition should be considered.     

^18F-FLT与^18F-FDG评估化疗早期反应的细胞学研究

目的:比较18F-FLT与18F-FDG在评估肺腺癌化疗早期反应的敏感性和准确性.材料和方法:选择氟尿嘧啶、阿霉素、顺铂3 种化疗药物,分别与肺腺癌A549细胞共同孵育1、4、24和72 h,测定细胞摄取18F-FLT和18F-FDG的变化,与药敏试验MTT法测定的存活细胞数目和细胞抑制率比较,判断两种示踪剂评估化疗反应的敏感性和准确性. 结果:(1)18F-FDG摄取变化:化疗后1h, 除5-FU组18F-FDG摄取明显增高(120±8%,P<0.01)外,顺铂和阿霉素组基本不变.4h、24h,三组变化也无明显变化.72h,三组均明显降低(35±3%,50±2%,55±4%,P<0.01).(2)18F-FLT摄取变化:3种细胞抑制剂均引起18F-FLT摄取明显变化,但变化趋势不同.5-FU对18F-FLT摄取的影响是双相的,治疗后1 h、4h,摄取增加(145±12%,P<0.01 ;150±14%,P<0.01);24h和72h明显减少(43±4%,60±4%P<0.01).阿霉素和顺铂引起18F-FLT摄取变化趋势基本相同,治疗后1h就观察到18F-FLT摄取迅速减少(70±6%,85±4%,P<0.01),24h摄取几乎全部被抑制(26±2%,15±4%,P<0.01).72h摄取较对照组仍降低(35±1%,30±2%,P<0.01).结论:18F-FLT能否反映化疗反应取决于药物的作用机制,5-FU 治疗后激活了肿瘤 DNA 补救合成途径而使早期摄取增高,相反,顺铂和阿霉素则引起摄取减低. 18F-FDG 摄取变化不明显.     

^18F-FDG和^18F—FLTPET／CT诊断肺结节影响因素的多中心临床研究

目的:探讨18F-FDG和18F-FLT PET/CT诊断肺结节的影响因素,以提高PET/CT对肺结节的诊断价值.材料和方法:选择肺结节患者55例为研究对象,其中男性33例,女性22例,年龄17～82岁,28例为肺内孤立结节,其余为2～3个结节,结节大小0.6～11.0cm,所有患者均行肺部18F-FDG和18F-FLT PET/CT检查,分析18F-FDG和18F-FLT标准摄取值(SUV)与肺结节患者的性别、年龄、结节大小及病理类型等相互关系和意义.结果:55例肺结节患者,18F-FDG和18F-FLT标准摄取值与患者的性别、年龄、结节大小等均无统计学差异(P>0.05),18F-FDG标准摄取值与患者的病理类型亦无统计学差异(P>0.05),而18F-FLT标准摄取值与患者的病理类型有统计学差异(P<0.05).结论:肺结节患者结节的病理类型是影响18F-FLT标准摄取值的重要因素.18F-FLT PET/CT鉴别诊断肺结节良恶性具有重要的价值和意义.     

Clinical Significance of Diffuse 18F-FDG Uptake in Residual Thyroid Gland after Unilateral Thyroid Lobectomy

Purpose

We investigated the clinical significance of diffuse uptake in remaining thyroid after unilateral lobectomy for thyroid cancer.

Methods

A total of 144 thyroid cancer patients who underwent ¹⁸F-FDG PET/CT after lobectomy were enrolled in the present study. The PET/CT images were evaluated for the presence of diffuse ¹⁸F-FDG uptake with maximum SUV (SUVmax) >2.0 in the residual thyroid and placed into one of two groups: with diffuse uptake and without diffuse uptake group. Clinical, laboratory, and PET/CT parameters in both groups were compared. Correlations between SUVmax of thyroid and available parameters were analyzed.

Results

Forty-two of 144 patients (29.2%) had diffuse thyroid uptake (mean SUVmax: 3.2 ± 1.1). All patients with diffuse uptake and 96 (94.1%) without diffuse uptake were receiving thyroxine therapy (P = 0.09). Thyroid function tests showed that most patients were euthyroid status (78.6 vs. 85.3%, P = 0.36). TgAb levels were significantly higher in patients with diffuse uptake (338.0 ± 664.6 vs. 57.3 ± 46.4, P < 0.0001). Mean attenuation values in the diffuse uptake group were significantly lower (72.2 ± 15. vs. 97.0 ± 16.0, P < 0.0001). An inverse correlation was found between SUVmax and mean attenuation values of residual thyroid in all patients (r = −0.57, P < 0.0001) and subgroup with diffuse uptake (r = −0.31, P < 0.05).

Conclusion

In this study, diffuse ¹⁸F-FDG uptake in the residual thyroid after unilateral lobectomy was a relatively frequent finding and may be associated with chronic thyroiditis. This uptake is not influenced by thyroid status or thyroxine therapy. The ¹⁸F-FDG uptake is inversely correlated with mean attenuation value of thyroid.     

18F-FDG Uptake in Metaphyseal Growth Arrest Lines: A Case Study

ABSTRACT: Growth arrest lines (also referred to as Harris lines) refer to dense metaphyseal trabecular lines, perpendicular to the long axis of the bone. The phenomenon is seen only in patients with immature skeletal structure after periods of nutritional insufficiency, illness, and prolonged immobilization or bisphosphonates administration during which bone growth is inhibited. With resumption of bone growth, a dense trabecular line becomes visible, typically at the metaphyses of rapidly growing long bone. We describe F-FDG uptake in the growth arrest lines of a 7-year-old boy treated for left distal tibial osteosarcoma.     

The Clinical Role of Dual-Time-Point 18F-FDG PET/CT in Differential Diagnosis of the Thyroid Incidentaloma

Thyroid incidentalomas are common findings during imaging studies including ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) for cancer evaluation. Although the overall incidence of incidental thyroid uptake detected on PET imaging is low, clinical attention should be warranted owing to the high incidence of harboring primary thyroid malignancy. We retrospectively reviewed 2,368 dual-time-point ¹⁸F-FDG PET/CT cases that were undertaken for cancer evaluation from November 2007 to February 2009, to determine the clinical impact of dual-time-point imaging in the differential diagnosis of thyroid incidentalomas. Focal thyroid uptake was identified in 64 PET cases and final diagnosis was clarified with cytology/histology in a total of 27 patients with ¹⁸F-FDG-avid incidental thyroid lesion. The maximum standardized uptake value (SUVmax) of the initial image (SUV1) and SUVmax of the delayed image (SUV2) were determined, and the retention index (RI) was calculated by dividing the difference between SUV2 and SUV1 by SUV1 (i.e., RI = [SUV2 - SUV1]/SUV1 × 100). These indices were compared between patient groups that were proven to have pathologically benign or malignant thyroid lesions. There was no statistically significant difference in SUV1 between benign and malignant lesions. SUV2 and RI of the malignant lesions were significantly higher than the benign lesions. The areas under the ROC curves showed that SUV2 and RI have the ability to discriminate between benign and malignant thyroid lesions. The predictability of dual-time-point PET parameters for thyroid malignancy was assessed by ROC curve analyses. When SUV2 of 3.9 was used as cut-off threshold, malignancy on the pathology could be predicted with a sensitivity of 87.5 % and specificity of 75 %. A thyroid lesion that shows RI greater than 12.5 % could be expected to be malignant (sensitivity 88.9 %, specificity 66.3 %). All malignant lesions showed an increase in SUVmax on the delayed images compared with the initial images. But in the group of benign lesions, 37.5 % (6/16) showed a decrease or no change in SUVmax. Dual-time-point ¹⁸F-FDG PET/CT, obtaining additional images 2 h after injection, seems to be a complementary method for the differentiation between malignancy and benignity of incidental thyroid lesions.     

18F-FDG hPET/CT鉴别肺部肿块

目的评价18F-氟脱氧葡萄糖双探头符合线路显像对肺部占位病变鉴别诊断的意义.方法 18F-氟脱氧葡萄糖双探头符合线路显像检测47例,病理证实恶性肿瘤37例,良性病变10例.用目测法及半定量法测量病灶的靶/非靶比值,并且比较良、恶性肿瘤组之间病灶直径和靶/非靶的区别,以及病灶直径与靶/非靶之间的关系.结果①18F-氟脱氧葡萄糖双探头符合线路显像阳性40例,阴性7例,灵敏度97%,特异性60%,准确率89%,阳性预测率90%,阴性预测率85%.②47例中有病灶60个,其中恶性病灶46个,直径1.0～8.1 cm,平均(3.14±1.46) cm;良性病灶14个,直径0.8～7.8 cm,平均(3.21±2.48) cm(P＞0.05).46个恶性病灶和14个良性病灶的靶/非靶比值分别是1.57～20.75(平均7.64±4.92)和1.85～15.4(平均4.28±3.24)(P＜0.005).③本组病灶直径与靶/非靶比值之间有正相关关系(r=0.45,P＜0.05).结论 18F-氟脱氧葡萄糖双探头符合线路显像对鉴别诊断肺部良、恶性肿瘤有较大临床价值.     

Diagnosis of myocardial contusion after blunt chest trauma using 18F-FDG positron emission tomography

Cardiac contusion is an infrequent complication of blunt chest trauma. The definite diagnosis of myocardial contusion is complex and needs a number of examinations such as electrocardiography, echocardiography, cardiac enzyme and radionuclide perfusion scan. We present a patient who had a blunt chest trauma from a car accident resulting in an acute myocardial infarction without injury to coronary arteries. The non-viable myocardium was diagnosed with (18)F-fluorodeoxyglucose positron emission tomography (FDG PET) combined with (201)Tl perfusion single photon emission tomography (SPECT). This is the first report of FDG PET for the diagnosis of myocardial contusion in blunt myocardial trauma.     

肺门、纵隔淋巴结^18F-FDG PET显像结果回顾

目的：~(18)F-FDG PET显像已经广泛用于肿瘤的检测,但肺门与纵隔淋巴结可能出现的非特异性摄取干扰PET显像结果的判断。本文通过临床实际病例回顾,分析这种非特异淋巴摄取的显像特点。材料和方法：回顾429例行肺或全身PET检查,图像质量合格,排除淋巴瘤,有病理、临床材料证实或经长期随访符合终点分析标准的病例。重点分析肺门、纵隔淋巴结显影率、影像特点,并与病例的人口学、临床结果对比分析。结果：114例(26．6%)肺门、纵隔淋巴结显影。其中48例见于良性疾病,恶性疾病66例。非特异性摄取与性别关系不大,但60岁以上人群发生率(46．4%)明显高于中青年(17．9%)。肺门两侧横行分布者多为良性,涉及纵隔的纵行淋巴结多见于恶性疾病。结论：肺门淋巴结非特异性摄取有年龄与分布形式特点,有助于同恶性疾病的淋巴转移鉴别。     

18F-FDG PET/CT Diagnosis of Vagus Nerve Neurolymphomatosis

ABSTRACT: A 62-year-old woman was in remission from previously treated stage IV diffuse large B-cell lymphoma with cranial involvement. She presented with new-onset hoarseness of voice and choking; MRI of the brain showed disease recurrence in the left cavernous sinus. She was subsequently referred for F-FDG PET/CT with contrast for further evaluation of lymphomatous recurrence. F-FDG PET/CT not only revealed hypermetabolic activity in the left cavernous sinus correlating to the MRI findings but also showed an interesting manifestation explaining the patient's hoarseness of voice, being neurolymphomatosis along the left vagus nerve.     

子宫肌瘤~(18)F-FDG PET/CT显像高代谢机制的初步探讨

目的探讨18F-2-氟-2脱氧-D-葡萄糖(18F-FDG)正电子发射体层摄影术(PET)/CT显像上子宫肌瘤的高代谢表现及机制。资料与方法回顾性分析2007年7月至2010年8月接受PET/CT检查的受检女性(共1785例)的PET/CT图像,以18F-FDG摄取高于肝脏作为代谢增高的标准,子宫出现高代谢病灶者共147例,其中9例经病理证实为子宫肌瘤。结果 9例子宫肌瘤表现为18F-FDG代谢增高的受检者年龄34~57岁,平均46岁,子宫肌瘤18F-FDG代谢的18F-FDF最大标准摄取值(SUVmax)为4.4~20.4。绝经前期子宫肌瘤的18F-FDG摄取多见,且SUVmax高于绝经后期。绝经前期子宫肌瘤的18F-FDG摄取与月经周期无明显相关,但增殖期子宫肌瘤的SUVmax低于分泌期。结论子宫肌瘤可以表现为18F-FDG代谢增高,不应一概视为恶性。认识子宫肌瘤的高代谢表现有助于减少假阳性,提高诊断准确性。     

肿瘤患者心肌摄取18F-FDG程度与血糖水平的关系

目的研究血糖水平对心肌摄取18F-氟脱氧葡萄糖的影响.方法在406例符合探测检查的肿瘤患者中,选取心脏在显像范围内,且临床资料完整的141名患者.进行18F-氟脱氧葡萄糖肿瘤检测,分析心肌影像质量的分析,对比研究心肌摄取18F-氟脱氧葡萄糖的程度和血糖水平的关系.结果141例肿瘤检测患者心肌摄取18F-氟脱氧葡萄糖的程度与血糖水平无相关性(P＞0.05).结论肿瘤患者的心肌对18F-氟脱氧葡萄糖的摄取程度可能受血糖水平以外的其他因素影响,因此检查前血糖水平不能预测心肌显影的质量.     

胃恶性淋巴瘤的18F-FDG PET/CT表现与鉴别诊断

目的:分析胃淋巴瘤的18F-FDG PET/CT影像学特点,探讨其在胃淋巴瘤的诊断、鉴别诊断和病情评估中的价值。方法:17例经胃镜活检病理证实的胃淋巴瘤患者,包括13例弥漫性大B细胞淋巴瘤,3例粘膜相关淋巴组织B细胞淋巴瘤和1例NK/T细胞淋巴瘤,均在治疗前行PET/CT显像。结果:胃淋巴瘤的PET/CT表现以不同形式的胃壁增厚和显著增高的FDG代谢为主要特征,6例呈Ⅰ型表现(胃壁弥漫性增厚伴FDG代谢显著增高),7例呈Ⅱ型表现(胃壁节段性增厚伴FDG代谢显著增高),3例呈Ⅲ型表现(胃壁局限性增厚伴FDG代谢增高),1例呈Ⅳ型表现(胃壁多发结节样增厚伴FDG代谢串珠样增高);PET/CT评价4例仅累及胃壁,3例累及胃壁和淋巴结,10例累及胃壁、淋巴结和其它脏器。结论:胃淋巴瘤的18F-FDG PET/CT表现以Ⅰ型和Ⅱ型更为多见;18F-FDG PET/CT有助于淋巴瘤的诊断和病情全面评估。     

螺旋CT四期动态扫描对肝局灶性结节增生的诊断与鉴别诊断

目的 探讨肝局灶性结节增生(FNH)螺旋CT四期动态扫描的典型与非典型CT征象.方法 回顾性分析12例经手术病理证实为FNH 的病例的典型和不典型CT表现,每例都经CT平扫和四期动态增强扫描.结果 12例FNH病例中,10例单发,2例多发,共发现14个病灶.8例单发具有较典型的CT表现:如显示中心疤痕(6例) ,增强动脉期(25 s)明显均匀强化(除外疤痕) (7例),门脉期(50 s)仍明显强化,平衡期(90 s)稍高密度,延迟期(180 s)等或低密度以及增粗与扭曲的供血动脉(6 例) 等.4个病灶增强动脉期(25 s)明显不均匀强化,疤痕区不明显,门脉期和平衡期低密度,术前被误诊为肝细胞肝癌.另外2个病灶误诊为血管瘤.结论 FNH大多具有典型的动态CT增强征象,但少数征象不典型.     

18F-FDG和18F-FLT PET/CT不同诊断方法在肺部单发结节中的临床价值分析

目的：探讨18F-FDG和18F-胸腺嘧啶核苷（FLT）PET/CT不同的诊断方法对肺部单发结节的诊断价值。方法对40例发现肺部单发结节的患者行18F-FDG和18F-FLT PET/CT显像,所有病例均经病理或密切随访确诊,应用受试者工作特征（ROC）曲线比较18F-FDG SUVmax、18F-FLT SUVmax、18F-FLT SUVmax/同层面椎体SUVmax对肺部恶性肿瘤的诊断价值;18F-FDG和18F-FLT PET/CT两种显像结果均行视觉分析和半定量分析,比较不同诊断方法的诊断效能。结果18F-FDG SUVmax、18F-FLT SUVmax及18F-FLT SUVmax/同层面椎体SUVmaxROC曲线下面积分别为0.687、0.821和0.817。以18F-FDG SUVmax>2.5、18F-FLT SUVmax>2.0为恶性诊断标准、18F-FDG PET/CT视觉分析评分法、18F-FLT PET/CT视觉分析评分法4种方法诊断肺癌的灵敏度、特异度和准确率分别为88.2%、73.9%和80.0%;58.8%、82.6%和72.5%;94.1%、91.3%和92.5%;88.2%、65.2%和75.0%。结论18F-FLT SUVmax及18F-FLT SUVmax/同层面椎体SUVmax单独诊断肺部恶性肿瘤的价值较18F-FDG SUVmax高,且前两者可替换使用。18F-FDG PET/CT视觉评分法在肺部单发结节良恶性的诊断中效能最佳。     

肝脏占位性病变的CT诊断及鉴别诊断

目的探讨CT对肝脏占位性病变的诊断及鉴别诊断的价值。方法收集310例肝脏占位性病变(包括原发性肝癌72例,肝转移癌58例,肝血管瘤35例,肝脓肿21例,肝包虫病58例,肝囊肿66例)的临床和CT资料,分析肝脏占位病变的部位、数目、边界以及增强后的CT表现。结果肝脏占位性病变表现为单发或多发低密度灶,边界清或不清,增强后可有程度不一的强化或不强化。本组肝脏占位性病变各自均有典型的CT征象,大多能作出定性诊断。结论CT对肝脏占位性病变的诊断及鉴别诊断有很大的价值。