67Ga显像对肺结节病的诊断价值

目的:探讨67Ga显像对肺结节病的诊断价值.材料和方法:回顾性分析78例经病理证实为肺结节病病人的67Ga全身显像、X线胸片和CT的影像学表现.结果:具有泪腺和腮腺放射性摄取伴有纵隔和肺门淋巴结肿大者,67Ga全身显像诊断准确性为96.4%(53/55),明显高于X线平片和CT的诊断准确性(83.6%,46/55,P＜0.05).单纯纵隔和(或)肺门淋巴结肿大者,67Ga全身显像诊断准确性为73.7%(14/19),与X线平片和CT的诊断准确性(84.2%,16/19)相近(P＞0.05).肺内病灶伴或不伴有肺门淋巴结肿大者4例,两种诊断方法都没有明确诊断.结论:67Ga全身显像对于以纵隔和或肺门淋巴结肿大的结节病具有重要的诊断价值.     

18F-FDG PET与67Ga全身显像对淋巴瘤分期的临床价值

目的探讨^18F-脱氧葡萄糖(FDG)P田显像与^67Ga全身显像对淋巴瘤患者分期的临味价值。方法经组织病理检查诊断为淋巴瘤的23例患者，治疗前均行^18F—FDG PEF显像与^67Ga全身显像。PET显像为静脉注射^18F-FDG 111～185MBq(按体重2．22MBq／kg)，45～50min后行全身显像。^67Ga全身显像为静脉注射370MBq^67Ga，48～72h后行前位和后位颈、胸、腹和盆腔局部全身显像。图像分析采用定性分析方法，有异常放射性摄取增高的部位为阳性病变。结果^18F-FDGP田显像23例患者均阳性，共发现53个病灶；^67Ga全身显像示19例(82．6％)阳性，发现44个病灶(83．0％)。肿瘤病灶35．8％(19个)在头颈部，20．8％(11个)在腹部，34．0％(18个)在纵隔，9．4％(5个)在盆腔。^18F-FDG PET与^67Ga全身显像结果比较示，在19例患者中44个病灶两者显像结果一致。PET显像发现的53个病灶中，^67Ga全身显像有9个病灶阴性，分别位于头颈部(1个)、腹部(4个)、盆腔(2个)和腋窝(2个)，病灶直径范围为0．6～3．2cm。结论^18F-FDG PET显像在淋巴瘤分期中明显优于^67Ga全身显像。^67Ga显像诊断的灵敏度受病灶大小和位置的影响较PET显像更明显。     

86例肺结节病67Ga显像分析

目的探67Ga显像非典型或典型“熊猫脸”征象对肺结节病的诊断价值。方法回顾性分析86例经病理检查证实为肺结节病患者的67Ga全身显像资料，与185例非结节病患者67Ga显像结果对照。结果86例肺结节病患者中表现为泪腺和腮腺摄取放射性，呈典型“熊猫脸”征象并伴有纵隔和(或)肺门淋巴结肿大者39例，占45．3％；表现为泪腺或腮腺摄取放射性，呈非典型“熊猫脸”征象并伴有纵隔和(或)肺门淋巴结肿大者18例，占20．9％。所有表现为泪腺和(或)腮腺有放射性摄取、伴有纵隔和(或)肺门淋巴结肿大者均经病理检查确诊为结节病。在非结节病患者中未出现该征象。结论67Ga显像非典型与典型“熊猫脸”征象有同样的诊断价值，在伴有纵隔和(或)肺门淋巴结肿大时是诊断结节病的可靠征象。     

18F-FDG符合线路显像在恶性淋巴瘤诊断及疗效判断中的应用

目的 探讨^18F-脱氧葡萄糖(FDG)双探头符合线路显像在淋巴瘤诊断及疗效判断中的应用。方法 对病理检查证实的56例恶性淋巴瘤患者行^18F-FDG显像，并与同期CT、MRI或B超等影像检查结果(CI)进行对比分析。56例患者中治疗前9例，化疗中21例，放化疗后10例，术后复查16例。结果 ①9例治疗前患者中7例^18F-FDG显像阳性，8例CI检查阳性。^18F-FDG显像与CI显示的病灶部位基本一致。②21例化疗患者中12例^18F-FDG显像阳性，15例CI阳性，有3例患者CT示有肿大淋巴结，但FDG摄取未见异常。③对16例淋巴瘤术后患者行^18F-FDG显像寻找术后残余病灶，发现3例FDG异常摄取。④10例放化疗后患者中4例FDG摄取异常(纵隔2例，骨2例)。⑤对7例同期行^18F-FDG显像与骨显像的患者进行分析，发现两者所示骨病灶部位不尽一致。结论 ^18F-FDG显像是恶性淋巴瘤诊断、分期及疗效观察的重要手段之一，可及时发现手术后肿瘤残余、复发。^18F-FDG显像与骨显像相互补充，可提高诊断恶性淋巴瘤骨髓浸润的灵敏度。CT同机图像融合技术能帮助定位肿瘤。     

18F-FDG SPECT显像纵隔病变病灶/本底比值测定方法研究

目的探讨^18F-脱氧葡萄糖(FDG)SPECT显像纵隔病变病灶，本底比值(L/B)的准确测定方法。方法对临床确诊的23例纵隔病变患者行胸部^18F-FDG SPECT显像，应用同机融合CT图像和三维定位技术，在相应^18F-FDG显像中依次选择气道区、脂肪区、间隙区、血管区和心脏区作为本底区，分别测定29处良、恶性病灶的L/B，并进行统计学分析。结果应用不同本底区测定的L/B对纵隔内良、恶性病变的诊断准确性不同。其中以血管区和间隙区作为本底区的诊断灵敏度(分别为82．4％和75．6％)和特异性(分别为83．3％和75．0％)较高。结论^18F-FDG SPECT显像同机融合CT图像和三维定位技术可为纵隔内病灶L/B的准确测定提供条件。     

^18F—FDG PET显像与^99Tc^m—MDP全身骨显像诊断肿瘤远处转移的比较

目的 评价^18F-脱氧葡萄糖（FDG）PET肿瘤显像与^99Tc^m-亚甲基二膦酸盐（MDP）全身骨显像对检出骨和远处转移的价值。方法 对16例恶性肿瘤放化疗后的患者进行^18F-FDG PET显像和^99Tc^m-MDP全身骨显像，并对两种结果进行了比较。结果 16例肿瘤患者中^18F-FDG PET显像皆阳性，其中14例患者有远处转移，转移病灶共62处，其中骨转移病灶20处；在全身骨显像中，11例有局限性异常放射性浓聚，其中2例为单一病灶，9例为多发病灶，共检出病灶57处，另5例骨显像正常。结论 ^18F-FDG PET对恶性肿瘤的诊断具有较高的准确性和特异性，但对骨转移灶的诊断价值相对较差；^99Tc^m-MDP显像阴性或单一病灶的可疑转移瘤患者有必要进行^18F－FDG PET检查，以明确诊断其他远处转移灶。     

18F-FDG符合线路显像诊断骨转移瘤的价值及与99Tcm-MDP骨显像的比较

目的 评价^18F-脱氧葡萄糖(FDG)符合线路显像在骨转移瘤诊断中的价值，并与^99Tc^m-亚甲基二膦酸盐(MDP)骨显像进行比较。方法因怀疑恶性肿瘤或骨转移而行^18F-FDG符合线路显像者55例，41例于^18F-FDG检查前后4周内进行了^99Tc^m-MDP全身骨显像。其中30例骨转移瘤患者，15例无骨转移瘤，10例^18F-FDG显像示可疑肿瘤直接骨侵犯(单独进行分析)。结果 ^18F-FDG符合线路显像和骨显像对骨转移瘤的灵敏度、特异性、阳性预测值、阴性预测值、诊断准确性分别为100％，93％，97％，100％，98％和95％，50％，75％，86％，77％，前者特异性、阳性预测值、诊断准确性显著高于骨显像(P=0．024，0．035，0．007)；^18F-FDG显像发现30例骨转移瘤患者中的20例有骨外原发或转移肿瘤。10例^18F-FDG显像示可疑肿瘤直接骨侵犯患者中，4例被证实有骨受累，6例无骨受累，而骨显像对骨受累情况均作出了正确判断。结论 ^18F-FDG符合线路显像对骨转移瘤的诊断有较高的灵敏度和特异性，并能发现骨外原发或转移性肿瘤；^99Tc^m-MDP骨显像对骨转移瘤也有较高的灵敏度，但特异性较差。     

淋巴瘤骨髓浸润的18F-FDG PET显像研究

目的 用^18F-脱氧葡萄糖（FDG）PET显像研究淋巴瘤细胞骨髓浸润。方法 恶性淋巴癌患者30例，其中非霍奇金淋巴瘤（NHL）20例、霍奇金病（HD）10例，进行全身^18F-FDG PET显像。局灶性边缘清楚的淋巴结相应区域^18F-FDG浓聚视为恶性淋巴结显影。利用灰度色标，视觉分析骨髓及肝脏内^18F-FDG浓聚情况。骨髓的^18F-FDG分布不均，摄取高于肝脏，判断为骨髓^18F-FDG摄取异常；骨髓的^18F-FDG分布均匀，摄取低于或等于肝脏，判断为骨髓^18F-FDG摄取正常。所有患者均行髂棘的骨髓活组织检查。结果 30例中18例有淋巴结摄取^18F-FDG；12例淋巴结摄取^18F-FDG阴性患者中，8例NHL，4例HD。有26例患者的骨髓^18F-FDG摄取情况与骨髓组织学检查结果一致，其中骨髓有淋巴细胞浸润7例，无淋巴细胞浸润19例。有3例骨髓组织学检查阴性的患者，^18F-FDG PET示骨髓^18F-FDG摄取异常、骨髓有淋巴细胞浸润；1例NHL患者，骨髓组织学检查阳性但^18F-FDG PET示骨髓^18F-FDG摄取正常。结论 ^18F-DG PET全身显像能正确评价骨髓淋巴细胞浸润情况，减少对淋巴瘤分期所进行的骨髓组织学检查。     

^18F-FDG PET在淋巴瘤分期和治疗反应评价中的价值

^18F-FDG PET显像对淋巴瘤的诊断、分期作用显著，对淋巴瘤病灶的探测灵敏度和准确性高于67Ga显像。在化疗过程中和化疗后持续^18F-FDG PET阳性对预测复发有高灵敏度。治疗结束时^18F-FDG PET阴性提示患者预后好。与其他常规显像相比，^18F-FDG PET在监测淋巴瘤疗效、判断治疗反应方面有独特优势。     

18F-FDG PET显像用于鼻咽癌诊断及分期

目的 探讨^18F-脱氧葡萄糖（FDG）PET显像在鼻咽癌诊断中的价值。方法 回顾性分析33例鼻咽癌患者的^18F-FDG PET显像效果。其中初诊患者4例，治疗后29例。行常规头颈部或全身^18F-FDG PET显像。结果 ①33例患者中，鼻咽部有恶性病灶（原发或复发病灶）者16例，PET灵敏度为100％，假阳性2例，特异性为88．3％，准确性为93．9％。与PET显像前的21例CT或MRI结果相比较，PET3检出鼻咽部恶性病灶10例，较CT或MRI多检出2例。②33例中22例有转移灶，PET检出20例（90．9％），较PET显像前的其他检查多检出5例；PET显像和PET显像前的其他检查皆有3例假阳性。在检出转移病灶数方面，PET显像多发现1处或多处转移灶有13例，PET显像少发现转移灶的2例。结论 ^18F-FDG PET显像灵敏、准确、全面，在鼻咽癌的诊断、早期复发灶及全身转移灶检出方面有重要价值。     

Myocardial imaging with 18F-fluoro-2-deoxyglucose positron emission tomography and magnetic resonance imaging in sarcoidosis

Purpose Despite accumulating reports on the clinical value of ¹⁸F-fluoro-2-deoxyglucose positron emission tomography (¹⁸F-FDG PET) and magnetic resonance imaging (MRI) in the assessment of cardiac sarcoidosis, no studies have systematically compared the images of these modalities. Methods Twenty-one consecutive patients with suspected cardiac sarcoidosis underwent cardiac examinations that included ¹⁸F-FDG PET and MRI. The association of ¹⁸F-FDG PET and MRI findings with blood sampling data such as serum angiotensin converting enzyme levels was also evaluated. Results Eight of 21 patients were diagnosed as having cardiac sarcoidosis according to the Japanese Ministry of Health and Welfare Guidelines for Diagnosing Cardiac Sarcoidosis. Sensitivity and specificity for diagnosing cardiac sarcoidosis were 87.5 and 38.5%, respectively, for ¹⁸F-FDG PET, and 75 and 76.9%, respectively, for MRI. When the ¹⁸F-FDG PET and MRI images were compared, 16 of 21 patients showed positive findings in one (n = 8) or both (n = 8) of the two modalities. In eight patients with positive findings on both images, the distribution of the findings differed among all eight cases. The presence of positive findings on ¹⁸F-FDG PET was associated with elevated serum angiotensin-converting enzyme levels; this association was not demonstrated on MRI. Conclusions Both ¹⁸F-FDG PET and MRI provided high sensitivity for diagnosing cardiac sarcoidosis in patients with suspected cardiac involvement, but the specificity of ¹⁸F-FDG PET was not as high as previously reported. The different distributions of the findings in the two modalities suggest the potential of ¹⁸F-FDG PET and MRI in detecting different pathological processes in the heart.     

Usefulness of fasting 18F-FDG PET in identification of cardiac sarcoidosis.

Cardiac PET using (18)F-FDG under fasting conditions (fasting (18)F-FDG PET) is a promising technique for identification of cardiac sarcoidosis and assessment of disease activity. The aim of this study was to investigate the usefulness of fasting (18)F-FDG PET in detecting inflammatory lesions of cardiac sarcoidosis from a pathophysiologic standpoint. METHODS: Twenty-two patients with systemic sarcoidosis were classified into 2 groups of 11 each according to the presence or absence of sarcoid heart disease. Cardiac sarcoidosis was diagnosed according to the Japanese Ministry of Health and Welfare guidelines for diagnosing cardiac sarcoidosis with the exception of scintigraphic criteria. Nuclear cardiac imaging with fasting (18)F-FDG PET, (99m)Tc-methoxyisobutylisonitrile ((99m)Tc-MIBI) SPECT, and (67)Ga scintigraphy were performed in all patients. PET and SPECT images were divided into 13 myocardial segments and the standardized uptake value (SUV) of (18)F-FDG was calculated and defect scores (DS) for (99m)Tc-MIBI uptake were assessed for each segment. The total SUV (T-SUV) and total DS (TDS) were calculated as the sum of measurements for all 13 segments, and the diagnostic accuracy of fasting (18)F-FDG PET was compared with that of the other nuclear imaging modalities. In addition, pathophysiologic relationships between inflammatory activity and myocardial damage were examined by segmental comparative study using the SUV and DS. RESULTS: In patients with cardiac sarcoidosis, fasting (18)F-FDG PET revealed a higher frequency of abnormal myocardial segments than (99m)Tc-MIBI SPECT (mean number of abnormal segments per patient: 6.6 +/- 3.0 vs. 3.0 +/- 3.2 [mean +/- SD], P < 0.05). The sensitivity of fasting (18)F-FDG PET in detecting cardiac sarcoidosis was 100%, significantly higher than that of (99m)Tc-MIBI SPECT (63.6%) or (67)Ga scintigraphy (36.3%). The accuracy of fasting (18)F-FDG PET was significantly higher than (67)Ga scintigraphy. The T-SUV demonstrated a good linear correlation with serum angiotensin-converting enzyme levels (r = 0.83, P < 0.01), and the TDS showed a significant negative correlation with the left ventricular ejection fraction (r = -0.82, P < 0.01). In abnormal myocardial segments on the nuclear scan, the SUV showed a significant negative correlation with the DS (r = -0.63, P < 0.0001). CONCLUSION: This study suggests that fasting (18)F-FDG PET can detect the early stage of cardiac sarcoidosis, in which fewer perfusion abnormalities and high inflammatory activity are noted, before advanced myocardial impairment.     

不同图像采集和处理对^67Ga显像质量及病灶探查的影响

目的分析平面显像、非衰减校正（NAC）断层显像和CT衰减校正（AC）断层显像等^67Ga显像图像采集和处理模式对图像质量和病灶判断的影响。方法用美国GE Millennium^TM VG 5型SPECT／CT仪对31例活动期肺结节病患者行^67Ga平面显像、胸部NAC断层显像;并对断层图像行CTAC。图像分析：双盲法阅片,判断平面图像、AC和NAC断层图像的图像质量及病灶数;测量病变与周围正常组织的放射性计数,并测量其比值。采用SPSS10．0软件,行配对t检验和,检验。结果图像质量按照平面显像、NAC、AC顺序依次提高（χ^2=25．880,P〈0．001）。以活动期结节病患者SPECT／CT示放射性增高的肺门、纵隔淋巴结为“病灶”,平面显像发现“病灶”70个,漏诊“病灶”8个;NAC、AC断层图像均发现“病灶”78个。NAC图像中“病灶”的放射性计数明显低于AC图像中“病灶”的放射性计数（15．240±8．865和67．241±35．049,t=-17．230,P〈0．001）。和NAC图像比较,AC图像“病灶”与肺的放射性比值增高（t=-7．520,P〈0．001）,“病灶”与肝（t=3．298,P=0．001）及“病灶”与腰椎（t=7,032,P〈0．001）的比值降低。结论^67Ga平面显像因前后组织放射性分布叠加,可能导致漏诊。^67Ga NAC断层显像能够较为准确地确定病变淋巴结的三维位置,但图像计数率低、噪声较大。AC断层图像虽未能增加检出的病灶数,但能有效提高NAC计数率,改善图像质量。     

18F-FDG符合线路显像对食管癌术后复发转移的诊断价值

目的 探讨^18F-脱氧葡萄糖（FDG）符合线路显像对食管癌术后复发转移的诊断价值。方法 对29例临床怀疑复发转移的食管鳞状细胞癌术后患者行^18F-FDG符合线路显像，计算其诊断复发转移灶的灵敏度、特异性和准确性，并与CT诊断结果比较。结果 29例患者中符合线路显像真阳性19例，真阴性6例，假阳性、假阴性各2例，其诊断食管癌术后复发转移的灵敏度、特异性和准确性分别为90．5％（19／21例）、75．0％（6／8例）和86．2％（25／29例）；而CT诊断的灵敏度、特异性和准确性分别为71．4％（15／21例）、87．5％（7／8例）和75．9％（22／29例）。在符合线路显像与CT检查均阳性的13例患者中，CT检出病灶20个；而符合线路显像检出27个，比CT多检出的病灶包括食管癌复发，锁骨上、纵隔和肺门淋巴结及骨转移。结论 ^18F-FDG符合线路显像对食管癌术后复发转移的诊断具有较高的临床价值，尤其在临床疑有复发转移而常规影像学检查阴性时有重要意义。     

Comparative evaluation of 18F-FDG PET and 67Ga scintigraphy in patients with sarcoidosis.

67Ga scintigraphy has been used for years in sarcoidosis for diagnosis and the extent of the disease. However, little information is available on the comparison of 18F-FDG PET and 67Ga scintigraphy in the assessment of sarcoidosis. The purpose of this study was to compare the uptake of 18F-FDG and 67Ga in the evaluation of pulmonary and extrapulmonary involvement in patients with sarcoidosis. METHODS: Eighteen patients with sarcoidosis were examined. 18F-FDG PET was performed at 1 h after injection of 185-200 MBq 18F-FDG. 67Ga whole-body planar and thoracic SPECT images were acquired 72 h after injection of 111 MBq 67Ga. We evaluated 18F-FDG and 67Ga uptake visually and semiquantitatively using standardized uptake values (SUVs) and the ratio of lesion to normal lumbar spine (L/N ratio), respectively. The presence of pulmonary and extrapulmonary lesions was evaluated histopathologically or by the radiologic findings. RESULTS: Five patients had only pulmonary lesions, 12 patients had both pulmonary and extrapulmonary lesions, and 1 patient had only an extrapulmonary lesion. Both 67Ga planar and SPECT images detected 17 of 21 (81%) clinically observed pulmonary sites. The mean +/- SD of the L/N ratio was 1.97 +/- 1.09. 67Ga planar images detected 15 of 31 (48%) clinically observed extrapulmonary sites. The mean +/- SD of the L/N ratio was 1.17 +/- 0.33. 18F-FDG PET detected all 21 (100%) clinically observed pulmonary sites. The mean +/- SD of the SUV was 7.40 +/- 2.48. 18F-FDG PET detected 28 of 31 (90%) clinically observed extrapulmonary sites. The mean +/- SD of the SUV was 5.90 +/- 2.75. CONCLUSION: The results of this clinical study suggest that 18F-FDG PET can detect pulmonary lesions to a similar degree as 67Ga scintigraphy. However, 18F-FDG PET appears to be more accurate and contributes to a better evaluation of extrapulmonary involvement in sarcoidosis patients.     

18F-FDG符合线路显像在乳腺癌诊断中的初步应用

目的研究18F-FDGSPECT/CT符合线路正电子显像在鉴别乳腺肿块性质和乳腺癌术前淋巴结转移分期中的应用价值。方法22例有乳腺肿块的女性患者行SPECT/CT符合线路18F-FDG显像,患者禁食6h以上,肘静脉注射18F-FDG185MBq～296MBq。静注60min后开始发射和X线CT透射扫描,然后进行符合线路PET连续采集30min。图像经X线衰减校正和有序子集最大期望值法(COSEM)叠代重建后,得到横断面、冠状面、矢状面三维断层图像及CT与FDGSPECT的融合图像。结果22例患者均通过手术切除治疗并获得病理结果。其中,乳腺癌16例,乳腺良性肿瘤6例。FDGSPECT诊断乳腺癌的敏感度、特异性和准确度分别是93.75%、100%和95.45%,明显高于乳腺X射线摄片。16例乳腺癌患者,15例FDGSPECT分期与临床手术分期一致。利用SPECT/CT仪所配备的定位CT,15例乳腺癌患者的病灶可准确定位。结论SPECT/CT符合线路18F-FDG显像在乳腺癌的诊断、转移灶定位以及临床分期方面具有重要的临床应用价值。     

Functional imaging of malignant paragangliomas and carcinoid tumours

Complete staging is mandatory for the management and therapy of neuroendocrine tumours. Various radiotracers are available but the best imaging strategy has yet to be defined. In this study we retrospectively compared 123I-MIBG, 111In-[D-Phe1]-DTPA-octreotide and 18F-FDG (PET) imaging in 15 patients with metastatic neuroendocrine tumours (11 carcinoid tumours, 4 paragangliomas). Planar images were acquired 1, 4, 24 and 48 h following the injection of 111In-[D-Phe1]-DTPA-octreotide and 123I-MIBG. Whole-body PET scans were performed 45 min after injection of 18F-FDG. 111In-[D-Phe1]-DTPA-octreotide was positive in 11/15 patients and identified 44 lesions, 18F-FDG PET was positive in 11/15 patients and identified 107 lesions and 123I-MIBG was positive in 8/15 patients and identified 67 lesions. No single scintigraphic technique identified all metastatic sites. In one patient all studies were negative. 18F-FDG PET identified more abnormal sites than the other two modalities. Combination of all three imaging modalities with X-ray CT helps to provide a more comprehensive map of the disease.     

^18F-FDG符合线路显像在胸腺上皮肿瘤诊断中的应用价值

目的探讨^18F-脱氧葡萄糖（FDG）符合线路显像在胸腺上皮肿瘤（TET）诊断中的价值。方法回顾性分析37例TET患者的^18F—FDG符合线路显像结果,图像分析采用视觉分析及半定量方法[肿瘤／正常肺组织放射性比值（TLR）]。按WHO TET病理学分类结果将患者分成3组（高生存率组,包括A、AB、B1型;中生存率组,包括B2、B3型;低生存率组,包括胸腺癌）;同时将^18F—FDG显像结果与增强CT影像进行对比,TLR与免疫组织化学检查所测Ki67标记指数（细胞增殖指标）进行相关性分析。组间TLR比较采用方差分析。结果（1）^18F—FDG符合线路显像阳性率91．9％（34／37）;（2）3个不同生存率组TLR间差异有统计学意义（高、中、低生存率组TLR依次为：1．42±0．27,2．13±0．74,3．00±1．19,F=9．99,P〈0．05）;（3）TLR与Ki67标记指数有明显相关性（r=0．613,P=0．002）;（4）^18F-FDG显像发现2例增强CT未发现的病灶,病灶分别位于前胸壁和右锁骨上淋巴结;（5）共有4例伴发重症肌无力。结论^18F—FDG符合线路显像有助于WHO TET病理学分类和发现更多的TET侵犯、转移灶;可以用^18F—FDG在TET的浓聚程度反映细胞的增殖活力。     

Isolated muscular sarcoidosis causing fever of unknown origin: the value of gallium-67 imaging.

An unusual case of a patient with a long-standing fever of unknown origin (FUO) is presented whose gallium-67 (67Ga) images revealed increased activity only in the calf muscles bilaterally. Other imaging modalities also failed to show chest or other abnormal findings. Subsequent biopsy of the right gastrocnemius muscle revealed noncaseating granulomas consistent with the diagnosis of sarcoidosis. When using 67Ga to evaluate a patient with a FUO, imaging of the extremities should always be included. Also, when abnormal Ga-67 uptake is present in the extremities, sarcoidosis should be included in the differential diagnosis.     

Fever of unknown origin: prospective comparison of [18F]FDG imaging with a double-head coincidence camera and gallium-67 citrate SPET

Gallium-67 citrate is currently considered as the tracer of first choice in the diagnostic workup of fever of unknown origin (FUO). Fluorine-18 2'-deoxy-2-fluoro-D-glucose (FDG) has been shown to accumulate in malignant tumours but also in inflammatory processes. The aim of this study was to prospectively evaluate FDG imaging with a double-head coincidence camera (DHCC) in patients with FUO in comparison with planar and single-photon emission tomography (SPET) 67Ga citrate scanning. Twenty FUO patients underwent FDG imaging with a DHCC which included transaxial and longitudinal whole-body tomography. In 18 of these subjects, 67Ga citrate whole-body and SPET imaging was performed. The 67Ga citrate and FDG images were interpreted by two investigators, both blinded to the results of other diagnostic modalities. Forty percent (8/20) of the patients had infection, 25% (5/20) had auto-immune diseases, 10% (2/20) had neoplasms and 15% (3/20) had other diseases. Fever remained unexplained in 10% (2/20) of the patients. Of the 20 patients studied, FDG imaging was positive and essentially contributed to the final diagnosis in 11 (55%). The sensitivity of transaxial FDG tomography in detecting the focus of fever was 84% and the specificity, 86%. Positive and negative predictive values were 92% and 75%, respectively. If the analysis was restricted to the 18 patients who were investigated both with 67Ga citrate and FDG, sensitivity was 81% and specificity, 86%. Positive and negative predictive values were 90% and 75%, respectively. The diagnostic accuracy of whole-body FDG tomography (again restricted to the aforementioned 18 patients) was lower (sensitivity, 36%; specificity, 86%; positive and negative predictive values, 80% and 46%, respectively). 67Ga citrate SPET yielded a sensitivity of 67% in detecting the focus of fever and a specificity of 78%. Positive and negative predictive values were 75% and 70%, respectively. A low sensitivity (45%), but combined with a high specificity (100%), was found in planar 67Ga imaging. Positive and negative predictive values were 100% and 54%, respectively. It is concluded that in the context of FUO, transaxial FDG tomography performed with a DHCC is superior to 67Ga citrate SPET. This seems to be the consequence of superior tracer kinetics of FDG compared with those of 67Ga citrate and of a better spatial resolution of a DHCC system compared with SPET imaging. In patients with FUO, FDG imaging with either dedicated PET or DHCC should be considered the procedure of choice.