3.0T MR TSE-17-db-iPAT T_2WI序列在周围型肺肿块诊断中的价值

目的：探讨3．0 T MR TSE-17-db-T2-iPAT T2WI序列对周围型肺肿块各种形态学征象的显示能力及对肺良恶性肿块的诊断价值。方法：对56例周围型肺肿块（直径1．5～6．3cm,平均3．47cm）行3．0TMRI,通过与常规CT对照,分析MRI对肿块的形态学征象,包括肿块的大小、形状、毛刺、分叶、内部结构及与支气管的关系等的检出及显示能力;采用5分制评分法对肿块的性质进行评分,评价CT、MRI诊断肺部良、恶性病灶的敏感性、特异性。结果：3．0TMR TSE-17-db-iPAT T2WI对显示肿块的大小、形状和分叶能力与CT比较差异无显著性意义（P〉0．05）;CT显示肿块血管集束征（16例）、肿块与支气管关系（12例）比MRI（分别为7和4例）更有优势（P〈0．05）;而3．0TMR TSE-17-db—iPAT T2WI显示肿块内部结构（47例）比CT（13例）更有优势（χ2=32．03,P〈0．01）;评分大于等于3分（病灶不确定,但可能为恶性）判为癌症,MRI诊断周围型肺肿块的敏感度为73．7％,特异度为50．0％;CT诊断周围型肺肿块的敏感性为81．6％,特异性为55．6％。结论：3．0TMR TSE-17-db-iPAT T2WI序列对显示肺内肿块内部结构比CT更有优势;在周围型肺肿块的鉴别诊断中有-定价值。     

MRI在良、恶性胸膜肿瘤鉴别诊断中的价值

目的：探讨磁共振成像在良、恶性胸膜肿瘤鉴别诊断中的作用。方法：对45例胸膜肿瘤患者（良性8例,恶性37例）进行了CT和MRI检查。评估分析良、恶性胸膜肿瘤的CT和MRI形态学特点及其分别在T1WI、T2WI和增强T1WI上的信号特点。结果：在CT图像上,共出现弥漫性胸膜增厚30例（恶性29例,良性1例）,纵隔胸膜受累28例（恶性27例,良性1例）、环绕或不规则胸膜增厚23例（恶性22例,良性1例）,胸壁或膈肌浸润9例（全部为恶性）;在MRI上,共出现弥漫性胸膜增厚32例（恶性31例,良性1例）,纵隔胸膜受累29例（恶性27例,良性2例）、环绕或不规则胸膜增厚24例（恶性23例,良性1例）,胸壁或膈肌浸润1例（全部为恶性）。根据前述形态学特点,CT与MRI对诊断胸膜恶性肿瘤总的敏感性分别为83．8％和86．5％,总特异性均为62．5％。结论形态学及信号特点,MRI对诊断良、恶性肿瘤病变的敏感性为97．3％,特异性为100％。结论：单纯依据其形态学特点,MRI对胸膜肿瘤的发现与诊断价值与CT相仿。但当MR信号与形态学特点结合时,其对良、恶性胸膜肿瘤的鉴别诊断价值则明显优于CT。     

胃肠道平滑肌瘤和平滑肌肉瘤的CT表现

目的：探讨CT在胃肠道平滑肌瘤和平滑肌肉瘤诊断中的应用价值。方法：本文收集了12例（男8例,女4例,平均年龄56．1岁）经手术病理证实的胃肠道平滑肌瘤（5例）和平滑肌肉瘤（7例）。12例均作CT检查,其中3例作了胃镜检查,6例作了胃肠道钡餐造影检查。结果：胃是胃肠道平滑肌瘤和平滑肌肉瘤最好发部位,除直接浸润和远处转移提示为恶性外,肿瘤大、分叶状、不均匀强化及溃疡形成均提示平滑瘤可能性大。结论：CT在胃肠道平滑肌瘤和平滑肌肉瘤的诊断与鉴别诊断中优于胃镜和胃肠道钡餐造影检查。     

PET／C T 数学预测模型对孤立性肺结节诊断价值的 ROC曲线分析

目的：利用ROC曲线分析评价 PET／CT 数学预测模型对孤立性肺结节的诊断价值。方法回顾性分析2011年9月～2013年6月我院因诊断为SPN而行PET／CT检查的186例患者。以病灶良恶性结果为应变量,以患者的性别、年龄及病灶的大小、部位、CT值、边界、磨玻璃成分、分叶、血管集束、胸膜牵拉、毛刺、钙化、空泡、空洞、SUVmax作为自变量行单因素和多因素分析,建立诊断SPN良、恶性的回归数学模型。计算PET／CT数学预测模型诊断SPN的灵敏度、特异度、准确性、阳性预测值、阴性预测值,绘制相应ROC曲线并计算曲线下面积大小。结果经二元logistic回归分析建立PET／CT诊断SPN良、恶性的数学模型如下：p＝ex／（1＋ ex ）,x＝‐8．111＋0．091×年龄＋1．351×分叶＋3．565×血管集束＋2．153×胸膜牵拉＋0．447× SUVmax。以数学模型对SPN良恶性进行预测,其诊断SPN的灵敏度、特异度、准确性、阳性预测值及阴性预测值分别为87．8％、81．0％、85．5％、90．0％及77．3％。 PET／CT 数学预测模型诊断SPN的ROC曲线下面积为0．927＆#177;0．019。结论以logistic回归分析构建的PET／CT数学预测模型诊断SPN的准确性较高,且不受人为因素干扰,因此其临床应用的可行性较高,是一种值得推荐的方法。     

磁共振扩散加权成像在胃肠道良、恶性病变诊断中的应用价值

目的探讨MR扩散加权成像（DWI）在胃肠道良、恶性病变诊断中的价值。资料与方法对69例胃肠道病变进行常规MR平扫和DWI,扩散敏感梯度（b值）分别为0和700s／mm^2,测量病变的表观扩散系数（ADC）值,其中29例同时续行增强扫描。结果59例恶性病变的平均ADC值为（0．96±0．11）×10^-3mm^2／s,10例良性病变的平均ADC值为（1．49±0．12）×10^-3mm^2／s,两组病变之间比较差异有统计学意义（P〈0．01）。将恶性病变ADC值95％可信区间上界1．16×100mm^2／s定位为良、恶性病变鉴别的界值,诊断敏感性为86．6％,特异性为95．8％。结论DWI有助于对胃肠道良、恶性病变的诊断和鉴别。     

18F-FDGPET／CT联合腹部增强CT对诊断胰腺癌及评估肿瘤可切除性的临床应用

目的评价18F-脱氧葡萄糖（FDG）PET／CT联合腹部增强CT对诊断胰腺癌、鉴别诊断胰腺良恶性病变以及评估肿瘤可切除性的临床应用价值。方法回顾性分析行18F—FDGPET／CT和腹部增强CT检查并经病理检查或临床等方法证实的48例原发性胰腺病变患者的资料,其中胰腺癌34例,胰腺良性病变14例。对胰腺癌和胰腺良性病变患者最大标准摄取值（SUVmax）进行t检验;比较分析单独PET、腹部增强CT、PET／CT、PET／CT联合腹部增强CT4种方法的图像特征和诊断价值,对灵敏度和准确性进行x2检验,对特异性进行Fisher确切概率法检验。结果34例胰腺癌患者与14例胰腺良性病变患者的SUVmax（5．91±2．90和2．24±1．13）差异有统计学意义（t=4．56,P〈0．01）。PET／CT联合腹部增强CT诊断胰腺癌的灵敏度、特异性和准确性分别为97．1％（33／34）、92．9％（13／14）和95．8％（46／48）,与单纯PET的88．2％（30／34）、64．3％（9／14）和81．2％（39／48）相比,x2=0．863和P=0．352,P=0．038,X2=5．031和P=0．024;与腹部增强CT的76．5％（26／34）、71．4％（10／14）和75．0％（36／48）相比,x2=6．274和P=0．012,P=0．042,x2=8．362和P=0．003;与PET／CT的88．2％（30／34）、78．6％（11／14）和85．4％（41／48）相比,x2=0．863和P=0．352,P=0．048,x2=3．928和P=0．047。PET／CT全身显像几乎发现了全部转移灶,使14例胰腺癌患者避免了不必要的外科手术;PET／CT可对单独PET显像诊断的胰腺癌患者胰腺外假阳性病灶进行正确诊断,使1例胰头癌患者分期下调,进行了外科手术。腹部增强CT通过多期显像,可以准确判断肿瘤对胰腺周围主要血管的侵犯程度,腹部增强CT按血管受侵程度评估肿瘤可切除性的准确性为83．3％（15／18）,不可切除的准确性为9／9。结论PET／CT联合增强CT对于诊断胰腺癌、鉴别胰腺良恶性病变及评估肿瘤的可切除性准确性有一定临床价值。     

正电子发射计算机体层摄影-CT诊断骨转移瘤的临床价值

目的 应用^18氟-脱氧葡萄糖（^18F-FDG）正电子发射计算机体层摄影（PET）-CT全身显像，探讨PET、同机CT和PET—CT融合图像在骨转移瘤诊断中的价值。方法 共332例^18F-FDG PET—CT受检者中有35例发现骨异常病变。分别阅读和记录^18FDG PET图像、同机CT图像和PET-CT融合图像判断的良、恶性病变，比较3种方法在诊断骨转移瘤上的差异。结果 35例中共检出89个病灶，其中68个病灶最后确诊为恶性肿瘤骨转移，21个为良性病变。PET诊断骨转移病灶62个，诊断良性病变17个，诊断骨转移瘤的敏感性为91．2％（62／68个），特异性为81．0％（17／21个），准确性为88．8％（79／89个）；同机CT诊断骨转移病灶55个，良性病变16个。诊断骨转移瘤的敏感性、特异性和准确性分别为80．9％（55／68个），76．2％（16／21个）和79．8％（71／89个）；PET．CT融合图像诊断骨转移病灶64个，良性病变19个，诊断骨转移瘤的敏感性、特异性和准确性分别为94．1％（64／68个），90．5％（19／21个）和93．2％（83／89个）。结论 PET-CT融合图像在诊断骨转移瘤方面，可减少单用PET或单用CT诊断时的假阴性和假阳性，提高了鉴别骨良、恶性病变的能力。     

CT导引下胸部病变穿刺活检的临床分析

目的：评价CT导引下穿刺活检在胸部病变诊断中的价值。方法：有手术病理或临床随诊的胸部病变CT穿刺活检223例，其中125例133次活检为传统CT导引下活检，其余98例105次CT穿刺活检应用激光导引装置。结果：223例胸部病变中212例有临床诊断结果，CT穿刺活检诊断正确率为82．1％（174／212），对恶性病变的敏感率86．2％（131／152），特异性100％、对良性病变明确诊断率为71．7％（43／60）。并发症包括13．0％（31／238）发生气胸，1．3％（3／238）需要放胸腔引流管，5．0％（1／238）发生肺实质少量出血，0．8％（2／238）出现少量咳血。激光导引下CT穿刺活检诊断正确率为88．4％（84／95），明显高于传统CT导引下活检76．9％（90／117）的诊断正确率，两者在气胸发生率、每次活检平均胸膜穿刺次数方面无统计学差异。结论：CT导引下胸部病变穿刺活检是一种安全、准确、有效的诊断及鉴别诊断方法。激光导引装置在胸部CT穿刺活检中有较高的应用价值，尤其对于小病灶和中心性病变。与传统CT导引下活检相比激光导引下CT活检可提高诊断证确率、缩短活检时间。     

原发性十二指肠恶性肿瘤的影像学诊断

目的 探讨X线、CT及血管造影对原发性十二指肠恶性肿瘤的诊断价值及鉴别诊断。资料与方法 回顾分析经手术和／或病理证实的46例原发性十二指肠恶性肿瘤的l临床及影像学资料，46例全部作过十二指肠气钡双对比造影，并有13例作低张十二指肠插管造影；28例作CT检查；11例作数字减影血管造影。结果 胃十二指肠双对比造影及低张十二指肠插管诊断十二指肠癌24例；平滑肌肉瘤6例；恶性淋巴瘤4例。诊断总符合率为73．91％(34／46)。误诊率为17．39％(8／46)，漏诊率为8．7％(4／46)。CT检查28例，确诊十二指肠癌4例，平滑肌肉瘤7例。误诊为腹腔脓肿2例，平滑肌瘤6例，腹腔恶性肿瘤9例。诊断符合率为39．29％(11／28)，误诊率为60．71％(17／28)。血管造影11例，9例检出病变，6例确诊为十二指肠恶性肿瘤，3例误为良性肿瘤，2例未发现明显肿瘤血管。确诊率为54．55％(6／11)，误、漏诊率分别为27．27％(3／11)、18．18％(2／11)。结论 胃十二指肠气钡双对比造影是发现十二指肠恶性肿瘤最简单易行的方法，它和胃镜配合能得到病理学诊断。低张十二指肠插管造影对重度肠腔狭窄或阻塞患者显示病变范围起补充作用。CT能显示管外型恶性肿瘤的软组织块影及管壁破坏和有无淋巴结肿大。血管造影能根据血供来源明确钡餐难发现、CT仅显示与肠管无明显联系的平滑肌肉瘤，并可进行栓塞IE血治疗。     

18F-FDG符合线路SPECT/CT显像半定量分析对肺部病变的诊断价值

_目的：探讨18 F-FDG 符合线路 SPECT/CT 显像对肺部病变的诊断价值。方法：回顾性分析经病理或随访证实的144例肺部病变患者的18 F-FDG 符合线路 SPECT/CT 检查图像,采用半定量法测量肺部病灶放射性计数（T）与胸壁软组织放射性计数（NT）,并计算其放射性摄取比值 R（T/NT）,应用受试者工作特征（ROC）曲线确定肺部良恶性病变的最佳临界值 R（cutoff）,即 R≥R（cutoff）诊断为恶性病变,R＜R（cutoff）诊断为良性病变。结果：R（cutoff）取3．58,即病灶R≥3．58作为恶性的判定标准,诊断敏感度、特异度、准确率、阳性预测值和阴性预测值分别为89．5％、89．7％、89．6％、95．9％和76．1％,且与病理诊断的一致性良好（Kappa＝0．750,P＜0．05）。结论：18 F-FDG 符合线路 SPECT/CT 显像对肺部病变的诊断、鉴别诊断及预后评估具有重要的临床应用价值。     

CT在原发性十二指肠恶性肿瘤诊断中的价值

目的:探讨CT在原发性十二指肠恶性肿瘤中的诊断及鉴别诊断价值。方法:回顾性分析36例经手术病理证实的原发性十二指肠恶性肿瘤患者的CT检查资料,并与手术病理结果进行对照。结果:36例原发性十二指肠恶性肿瘤中十二指肠腺癌30例,恶性间质瘤3例,恶性淋巴瘤1例,神经内分泌癌2例。十二指肠腺癌CT表现为十二指肠局部软组织肿块影,伴肠腔不规则狭窄;恶性间质瘤CT表现多为较大软组织肿块,有明显强化,肿块多腔外生长;恶性淋巴瘤CT表现肿瘤累及肠管范围较长,肠壁增厚明显,呈轻-中度强化,但肠梗阻症状不明显;神经内分泌癌CT表现软组织肿块或结节影,强化较明显。结论:CT检查对原发性十二指肠恶性肿瘤有重要的诊断价值及鉴别诊断价值。     

^18F—FDG双探头符合探测显像诊断恶性肿瘤的初步应用

目的 :探讨 18F -FDG双探头符合探测对恶性肿瘤诊断的价值。材料和方法 :2 2例原发及转移瘤患者接受了18F FDG双探头符合探测显像 ,及CT、超声检查 ,对照病理证实结果比较分析了几种影像技术的诊断效率。结果 :18F FDG双探头符合探测、CT、超声检出肿瘤的准确率分别是 94% ,69% ,69%。个别分化程度较高或太小的病灶出现18F FDG显像假阴性 ;炎性病灶可造成假阳性表现。结论 :18F FDG双探头符合探测对肿瘤原发及转移灶检测方面有较高的价值 ,但需与其他临床资料综合分析得出结论。     

CT and MRI features of recurrent tumors and second primary neoplasms in pediatric patients with retinoblastoma

OBJECTIVE: The aim of our study was to describe the CT and MRI findings of recurrent tumors and second primary (malignant and benign) neoplasms in patients with retinoblastoma and to evaluate imaging features to assist in distinguishing them. MATERIALS AND METHODS: Records of 445 pathologically confirmed retinoblastomas were retrospectively reviewed. Thirty-four patients with recurrent retinoblastomas and 15 patients with second primary neoplasms who underwent CT and MRI were evaluated by two radiologists with agreement by consensus. RESULTS: Invasive patterns of recurrent tumors included type A, intraocular tumor (n = 13); type B, intraorbital tumor with spread into the optic nerve shown as enlargement and marked enhancement of the optic nerve on contrast-enhanced CT or MRI (n = 6); and type C, tumor extending to the lateral aspect of the orbit and invading the brain via the sphenoidal bone (n = 2). Thirty-eight percent of patients with recurrent tumors had distant metastases (n = 7) or leptomeningeal metastases (n = 6). Leptomeningeal metastases were found only in recurrent tumors. Second primary neoplasms included osteosarcoma (n = 5), rhabdomyosarcoma (n = 5), meningioma (n = 4), and other tumors (n = 3). A significant difference was seen between the patients' ages at the time of diagnosis of recurrent tumors and second primary neoplasms (p < 0.0001). Extraorbital tumors were found more frequently among second primary neoplasms than among recurrent tumors (p < 0.001). CONCLUSION: Both recurrent tumors and second primary neoplasms in patients with retinoblastoma often show characteristic imaging features. The tumor distribution on CT and MRI may help in differentiating recurrent tumors and second primary neoplasms.     

十二指肠间质瘤的MSCT诊断

目的:探讨十二指肠间质瘤的多层螺旋CT(MSCT)表现及诊断价值.方法:回顾性分析经手术或病理证实的14例十二指肠间质瘤患者的MSCT平扫及双期增强扫描资料,并结合三维重组进行观察.结果:14例十二指肠间质瘤肿瘤中降部7例,水平部4例,升部3例.良性间质瘤5例,均向腔内生长,呈圆形或类圆形,与肠壁等密度、密度均匀,边界清.恶性间质瘤6例,向腔外生长5例、腔内外生长1例,肿瘤边缘有分叶,密度不均匀,2例可见囊变坏死及气体影,明显不均匀强化5例,明显均匀强化1例,周围组织侵犯或远处转移5例.潜在恶性3例,向腔外生长2例,腔内外生长1例,平扫等密度、密度均匀,临近肠壁增厚,不均匀强化.CT检查的敏感度为100%,定位准确率为92.1%(13/14),定性准确率78.6%(11/14).结论:MSCT双期增强扫描结合重建技术能准确显示十二指肠间质瘤的部位、形态、大小及供血血管,对鉴别肿瘤良恶性有重要临床价值.     

Malignant stromal tumors of the small intestine: report of 9 cases

PURPOSE: Analysis of imaging features of malignant stromal tumors of the small bowel and review of literature. MATERIAL AND METHODS: 9 cases of malignant stromal tumor of the small bowel with histological proof were imaged at US (8 cases), small bowel series (9 cases) and CT scan (3 cases). RESULTS: There were 6 cases of leiomyosarcoma and 3 cases of malignant schwannoma. Tumors involved the jejunum in 3 patients, the ileum in 4 patients, and the duodenum in 2 patients. The main clinical presentation was an abdominal mass (8 cases), which appeared heterogeneous and hypoechoic with eccentric lumen at US confirming its GI origin (7 cases). Small bowel series showed a bulky cavitary mass opacified via a thin fistula (7 cases), an ileo-ileal intussusception (1 case) and enlarged duodenal lumen (1 case). CT performed in 3 cases showed an intraperitoneal mass with soft-tissue density. A communication with the GI tract was noted in 1 case, and in another case, it showed an intestinal intussusception. US guided biopsy performed in 3 cases provided diagnosis in 2 cases (malignant schwannoma, leiomyosarcoma). Tumor growth was exophytic in 8 cases and dumbbell-shaped in 1 case. CONCLUSION: The imaging features of malignant stromal tumors of the small bowel are similar. It varies with the type of tumor growth and its size. The diagnosis may be suggested based on imaging features.     

Evaluation of pancreatic islet cell tumors by fluorine-18 fluorodeoxyglucose positron emission tomography: comparison with other modalities

PURPOSE: Pancreatic islet cell tumors are potentially malignant tumors and are often difficult to detect with current imaging modalities. Positron emission tomography (PET) using fluorine-18-labeled fluorodeoxyglucose (FDG) is an imaging technique with high sensitivity for malignant tumors. The aim of this study was to assess the feasibility of FDG PET to detect pancreatic islet cell tumors. METHODS: Nineteen lesions of histologically proved islet cell tumors were evaluated in 12 patients (5 men, 7 women; ages 22 to 77 years). FDG uptake was analyzed semiquantitatively as a standardized uptake value. The diagnostic accuracy of PET was compared with that of US, CT, and MRI. RESULTS: Of 19 lesions, 8 showed positive PET results (standardized uptake value > 2.3), and localization was indicated in 2 lesions. In nine tumors that were not detected by PET, seven were small tumors ranging from 1.5 to 8 mm in diameter and were not identified by other imaging methods. The sensitivity rate of PET was 53%, whereas those of US, CT, and MRI were 53%, 50%, and 53%, respectively. CONCLUSION: Our data suggest that FDG PET has a limitation in that it does not detect some small-sized islet cell tumors, mainly depending on their size, but it has potential utility as a complementary modality for other imaging techniques.     

Duodenal neoplasms: predictive value of CT for determining malignancy and tumor resectability.

CT examinations of 25 patients with proved primary or metastatic duodenal neoplasms were retrospectively reviewed to determine if morphologic features seen on CT scans could be used to predict the benign or malignant nature of these neoplasms and to assess the effectiveness of using CT findings to predict tumor resectability. We studied 19 malignant and six benign tumors. Histologic proof was obtained by means of surgery in 20 patients and by endoscopic biopsy in five. CT features of tumor morphology were assessed in the 22 cases in which a duodenal tumor was seen on CT. These features included central necrosis, ulceration or excavation, and the location of the tumor with respect to the bowel wall. The specific morphologic features used to predict that a tumor was malignant included the presence of an exophytic or intramural mass, central necrosis, and ulceration. The only criterion used to predict that a tumor was benign was that the mass be entirely intraluminal. Whenever vascular encasement, invasion of contiguous organs other than the head of the pancreas, distant lymphadenopathy, or metastases were present, the tumor was predicted to be unresectable for cure. With the exception of three benign smooth muscle tumors, all tumors with one or more CT morphologic features indicative of a malignant neoplasm were malignant (n = 16). Three of four intraluminal masses were benign. In three cases of polypoid tumors smaller than 2 cm, a duodenal tumor was not seen on CT. Whenever extraduodenal disease was found (15 cases), the neoplasms were malignant. In the 22 cases in which a tumor was detected on CT, the sensitivity of using the presence of one or more morphologic features associated with a malignant neoplasm as a predictor was 94%; the specificity was 50%, and the accuracy was 82%. If the presence of any morphologic feature indicative of a malignant neoplasm was combined with the presence of any finding of extraduodenal disease, CT was 100% sensitive and 86% accurate for predicting that the tumor was malignant. CT appears to be reliable for predicting duodenal tumor resectability. On the basis of CT findings, 10 tumors were correctly predicted as being unresectable for cure, and 12 were predicted as being resectable; no surgery was performed in the remaining three cases. In conclusion, evaluation of the morphologic features of duodenal neoplasms is a sensitive, but nonspecific, method for predicting that a tumor is malignant.(ABSTRACT TRUNCATED AT 400 WORDS)     

Imaging manifestations of pleural tumors.

Although radiologic assessment of pleural tumors may be accomplished with several imaging modalities, the standard noninvasive techniques include chest radiography and computed tomography (CT). These examinations may be supplemented with magnetic resonance imaging and occasionally with ultrasound. Depending on the location, size, and underlying histologic features, pleural tumors may produce a spectrum of findings. CT is particularly useful in defining the location and extent of these masses. The authors present a review of basic pleural anatomy and imaging features of both benign and malignant pleural neoplasms. The pleural may be involved by one of several primary or metastatic tumors. Specific cell types are diffuse malignant mesothelioma (the most common plain radiographic findings are unilateral pleural effusion and pleural thickening), localized fibrous tumor (circumscribed, spherical or ovoid, noncalcified lesions arising in the pleural surface), metastatic disease (radiographic findings may mimic those of malignant mesothelioma), and uncommon neoplasms including thymoma and lymphoma. Among these various pleural tumors, metastatic disease represents the most common neoplasm.     

Comparison of CT and MR imaging in musculoskeletal neoplasms

Magnetic resonance (MR) and CT of 50 musculoskeletal neoplasms were compared to investigate the relative values of these modalities in the assessment and staging of musculoskeletal neoplasms and to determine how often they are complementary and when they are redundant. The material included 25 benign and 25 malignant neoplasms, of which 33 were skeletal and 17 were of soft tissue origin. Magnetic resonance was superior to CT with respect to all morphologic criteria except for cortical bone destruction, calcification, ossification, and the assessment of lytic and sclerotic changes in flat bones. Magnetic resonance was found to be complementary to CT in 48% of the cases (30% malignant, 18% benign). Use of both MR and CT was considered redundant in 52% of the cases (20% malignant, 32% benign). Magnetic resonance was found to be the modality of choice for all benign and malignant soft-tissue neoplasms. Both modalities are complementary and necessary for complete evaluation of malignant skeletal tumors. Benign skeletal tumors should be considered for evaluation by CT, MR, or both on an individual case basis.     

Evaluation of hemangioma by positron emission tomography: role in a multimodality approach

PURPOSE: The relative utility of various preoperative diagnostic imaging modalities for the evaluation of hemangioma of the extremities, including positron emission tomography (PET) (using 18F-fluoro-2-deoxy-D-glucose [FDG] and fluorine-18 alpha-methyltyrosine [FMT]), computed tomography (CT), magnetic resonance imaging (MRI), and digital subtraction angiography (DSA), was investigated. METHODS: Imaging findings in 16 patients with 16 histopathologically documented hemangiomas of the extremities were retrospectively reviewed. Preoperative imaging included: FDG-PET (n = 16), FMT-PET (n = 12), MRI (n =16), CT (n =11), and DSA (n =14). RESULTS: All 16 lesions examined by PET with FDG and/or FMT showed accumulation. The standardized uptake values (SUVs) for FDG-PET for the 16 examined tumors ranged from 0.7 to 1.67; for FMT-PET, they ranged from 0.14 to 1.00. The SUVs with both tracers indicated the benign nature of the tumor. Computed tomography demonstrated variable attenuation and phleboliths in two patients. The MRI signal characteristics were relatively consistent: heterogeneous signals were slightly higher than those of skeletal muscle on T1-weighted images and brighter than those of subcutaneous fat on T2-weighted images. The pooling and cotton-wool staining depicted in DSA was found to be significantly correlated with FDG accumulation, suggesting that localized blood retention-induced ischemia may accelerate anaerobic glycolysis, which leads to high FDG uptake. CONCLUSION: Although plain radiography, CT, MRI, and angiography may provide anatomic extent and be pathognomonic, FDG-PET and FMT-PET may be the most reliable among the studied imaging modalities for differentiating benign hemangiomas from other soft tissue tumors, especially malignant neoplasms.