肝脏炎性肌纤维母细胞瘤组织学分型与CT、MRI对比分析(附19例报告)

目的 探讨肝脏炎性肌纤维母细胞瘤(HIMT)CT、MRI特征与病理改变的关系,提高对其的诊断准确率.资料与方法 经手术及病理证实的HIMT患者19例,其中男12例,女7例,年龄27～79岁,平均46.7岁.18例行CT平扫及增强扫描;1例仅行CT平扫,7例同时行CT、MRI平扫及增强扫描.结果 19例中15例为单发病灶,4例多发,共26个病灶,位于肝左叶4个,肝右叶22个.组织学分型包括黄色肉芽肿型15例:CT平扫低密度12例,等密度3例;14例增强扫描,动脉期1例明显强化,门静脉期轻度强化10例,平衡期轻度强化4例.4例行MRI检查,T1WI呈等信号1例,低信号3例,T2WI均为高信号.增强扫描4例动脉期均无强化,门静脉期或平衡期轻度强化.浆细胞肉芽肿型3例:CT平扫呈稍低密度2例,等密度1例.增强扫描动脉期均无强化,门静脉期或平衡期轻度强化;行MRI检查2例,增强扫描呈壁结节强化.硬化型1例:CT平扫为等、低混杂密度影,增强扫描动脉期无强化,门静脉期呈均匀强化,平衡期病灶密度减低.MRI平扫T1WI为等信号,T2WI为高信号,增强扫描动脉期无强化,门静脉期轻度强化,延迟期强化明显.26个病灶中4个有假包膜.结论 CT及MRI平扫及增强扫描能够反映HIMT组织学变化特点,但对不同类型病变的CT、MRI鉴别诊断仍比较困难.     

原发性透明细胞型肝癌的CT和MRI诊断

目的 探讨原发性透明细胞型肝癌的影像表现,评价CT和MRI对该病的诊断价值.方法 回顾性分析19例经手术病理证实的原发性透明细胞型肝癌的CT和MRI表现.13例行CT平扫和动态增强扫描,8例行MR T1WI、T2WI和动态增强扫描.结果 CT平扫13例病灶均为低密度,其中9例病灶内部见不规则的更低密度影.增强后动脉期所有病灶均有强化表现,9例病灶不均匀强化,病灶中心有无强化的低密度区.门静脉期11例病灶呈相对低密度,2例呈等密度.3例可见环形强化的包膜.MR T1WI上5例病灶为低信号,3例为稍高信号.T2WI上5例病灶为混杂高信号,3例为等、低信号.MRI增强动脉期所有病灶均有显著强化.门静脉期和延迟期7例病灶为相对低信号,1例为等信号.2例病灶见环形强化的包膜.结论 CT和MRI可显示原发性透明细胞型肝癌的特征性表现,有助于提高该病的诊断准确性.     

肾上腺淋巴瘤:双期增强CT诊断价值

目的 探讨肾上腺淋巴瘤的CT表现特征及其双期增强的诊断价值.资料与方法 回顾性分析经手术病理证实的B细胞型非霍奇金淋巴瘤8例,术前行CT平扫和双期增强检查.所有病例影像资料均经3名高年医师分析阅片,分别确定病变大小、形态、边缘、密度以及强化程度和类型.其中,2例同时作了MR检查.结果 8例肾上腺淋巴瘤11个病灶中,双侧3例,单侧5例;病灶呈椭圆形8个,三角形3个.肿瘤直径4.1～10.7 cm,平均6.3 cm.10个病灶CT平扫密度相对均匀,1个病灶密度不均匀,所有病灶密度高于大多数肾上腺肿瘤,平扫CT值为24.1～35.2 HU,平均25.5 HU;双期增强动脉期病灶轻度强化,均匀强化4个病灶,不均匀强化7个病灶,动脉期CT值28.3～44.7 HU,平均31.6 HU;门静脉期中度强化,所有病灶强化趋于均匀,门静脉期CT值36.4～62.6HU,平均48.7 HU.结论 肾上腺淋巴瘤密度相对均匀,密度高于大多数肾上腺肿瘤,坏死少见或范围较小,双期增强呈轻～中等程度进行性延迟强化,强化较均匀.     

胆管细胞型肝癌的CT诊断

目的探讨CT增强及延迟扫描诊断胆管细胞型肝癌的价值。方法对21例经病理证实的胆管细胞型肝癌做了CT平扫、增强及延迟扫描。结果CT平扫全部病灶为低密度,其中14例为囊性,7例为实质性且病灶内见胆管扩张。增强扫描14例囊性病变中有10例出现病灶边缘不连续的较薄环形增强,3例连续环行强化,门静脉期13例均无变化;1例无增强表现。7例实质性病变在增强1 m in后病灶轻度强化,3~8 m in后病灶出现延迟增强,密度等于或大于同层肝组织,扩张的胆管无变化。结论CT增强扫描囊性病灶边缘连续或不连续的薄环形强化且门静脉期无变化,实质性病灶延迟强化及病灶内胆管扩张是胆管型肝癌的特征性表现。     

原发性肝类癌的CT及MRI表现

目的 探讨原发性肝类癌的CT及MRI表现.方法 回顾性分析2003年12月至2008年11月间11例经手术病理证实的原发性肝类癌患者资料.4例行CT检查,8例行MRI检查,分析其影像表现特征.结果 11例中肿瘤多发2例,表现为2个或2个以上的结节状病灶,其余9例均为单发.CT检查4例患者病灶均表现为平扫边界清楚低密度,中心可见不规则更低密度区;增强后动脉期病灶实质部分不均匀强化,中心更低密度区无强化,门静脉期及延迟期病灶边缘仍轻度强化,强化程度较动脉期减低,中心坏死区始终无强化.MRI 8例患者中7例T_1WI表现为边界清楚的不均匀低信号,T_2WI病灶呈高信号,中心可见不规则低信号;增强后动脉期病灶边缘不均匀强化,病灶中心可见不规则无强化低信号区,门静脉期及延迟期病灶边缘仍轻度强化,边缘显示不清,病灶中心无强化低信号区范围较动脉期缩小.1例患者T_1WI表现为边界清楚的囊状低信号影,囊内可见高信号,T_2WI病灶呈高信号;增强后动脉期病灶边缘不均匀强化,门静脉期及延迟期呈低信号.结论 平扫和动态增强CT扫描及MRI能反映原发性肝类癌的影像特点,具有一定特征性.     

肝脏炎性肌纤维母细胞瘤CT诊断

目的 探讨肝脏炎性肌纤维母细胞瘤(inflammatory myofibroblastic tumor,IMT)的CT表现,以提高对本病的认识.资料与方法 9例经手术或穿刺活检病理证实的肝脏IMT均行CT平扫和增强多期扫描.结果 9例共10个病灶,平扫时9个病灶表现为低或稍低密度,增强动脉期8个病灶表现为轻度或不强化,门静脉期病灶进一步强化,8个病灶表现为轻度、中度强化,延迟期6个病灶表现为延迟强化.8个病灶出现周边环状强化或分隔状强化,3个呈"双环征"或"三环征",2个为"花瓣"状强化;10个病灶门静脉期均表现为边界清晰,5个有占位效应;动脉期显示灶周水肿4例,4例均伴发胆管扩张、结石.结论 肝脏IMT CT表现具有一定的特征性,分析其CT增强特征可与肝内其他病变鉴别.     

肝脏血管周上皮样细胞肿瘤1例

正患者女,51岁。因体检发现肝右叶占位入院,无肝炎、肝硬化病史。CT:肝右叶类圆形团块状等低密度影、内见少量点状脂滴(图1),病灶大小约150mm×116mm×225mm,增强后动脉期明显不均匀强化,边缘清晰见假包膜(图2),门静脉期持续强化,延迟期与正常肝实质呈等密度强化(图3,4);病灶由肝固有动脉分支及门静脉右支供血,肝右静脉引流,其内及边缘见迂曲扩张的畸形血管(图5)。CT诊断:多     

混合型肝脏血管平滑肌脂肪瘤的CT和MRI诊断

目的 探讨肝脏血管平滑肌脂肪瘤(hepatic angiomyolipoma,HAML)CT和MRI的诊断价值.资料与方法回顾性分析经病理证实的8例肝脏HAML的CT和MRI表现.8例均行CT平扫和多时相动态增强扫描,其中4例同时行MRI平扫和多时相动态增强扫描.结果 8例均为单发混合型HAML,CT平扫均表现为低于周围正常肝组织的混杂低密度,灶内含有不同程度的脂肪密度,CT值-40～40HU.4例MRI平扫表现为稍长T1(含短T1)、稍长T2混杂信号,T1WI上高信号在使用脂肪抑制技术后完全消失.CT与MRI多时相动态增强扫描显示动脉期病灶均呈显著不均匀强化,门静脉期6例CT、3例MRI病灶呈持续或渐进性中重度强化,高于周围正常肝实质,2例CT、1例MRI病灶轻中度强化;3例HAML见假包膜,且在门静脉期及延迟期有轻度强化.结论 CT和MRI能显示混合型HAML的特征性表现并可在术前做出准确诊断.     

非典型肝海绵状血管瘤的CT诊断

目的:探讨非典型肝海绵状血管瘤(HCH)的CT表现及相关病理学基础。方法:回顾性分析18例共21个非典型HCH的CT表现,包括病灶大小、平扫密度、动态增强模式及邻近改变。结果:有13个病灶CT平扫呈非均匀密度。共出现4种非典型动态增强模式:Ⅰ型(5例)表现为动脉期病灶快速均匀强化,门静脉期及延迟期持续强化;Ⅱ型(13例)动脉期肿瘤周边结节状强化,门静脉期及延迟期呈向心性强化,但不能完全填充整个病灶;Ⅲ型(2例)动脉期病灶呈中央强化,门静脉期及延迟期向周边呈离心性强化;Ⅳ型(1例)动脉期病灶无明显强化,门静脉期及延迟期呈轻度周边强化或不规则强化。HCH邻近区域的改变:有9个病灶周围可见动脉-门静脉分流(APVS),4个病灶邻近可见肝包膜回缩(HCR)征。以上非典型CT表现的出现在不同大小的病灶中差异有显著性意义(P<0.05)。结论:HCH非典型CT表现的出现与病变的结构特征密切相关,认识其非典型表现对HCH的诊断和鉴别诊断有重要意义。     

小肝癌的不典型CT表现分析及鉴别诊断

目的：探讨小肝癌（SHCC）在螺旋CT扫描中的不典型表现。方法：分析经手术病理证实的螺旋CT扫描中呈不典型表现的SHCC 22例共24个病灶的CT征象。结果：22例共发现24个病灶为不典型表现,其中10个病灶在动脉期强化明显,门静脉期和延迟期为等密度、略高密度或中心性斑点状强化;2个病灶动脉期和门静脉期为等密度,延迟期为低密度;7个病灶在动脉期、门静脉期和延迟期均呈低密度;5个病灶动脉期病灶边缘有环形强化或点状强化,门静脉期和延迟期仍有持续强化。结论：SHCC在螺旋CT扫描中有多种不典型表现,病灶的血供情况、病理学基础等是产生不典型表现的常见原因。     

CT机技术参数与CT片质量的相关性分析

目的初步探索CT机技术参数与CT成像照片质量的关系。方法对13台CT机分别进行技术参数检测。采集所检测CT机的若干照片，依本研究组制定的“CT片质量临床评分标准”对每张照片进行评分，对CT机技术参数与照片评分进行多元线性回归分析。结果CT机的技术参数：CT剂量指数(CTDI)、水的CT值、噪声、均匀性、高对比度分辨率、低对比度分辨率、CT值线性与CT成像照片评分存在线性回归关系，但其中仅低对比度分辨率对评分的影响有统计学意义(t=-2．460．P=0．049)。结论对技术参数检测合格的CT机，低对比度分辨率对CT成像照片质量有显著影响，其他技术参数对照片质量的影响有待于进一步研究。     

Initial experience with FDG-PET/CT in the evaluation of breast cancer

Purpose We retrospectively reviewed FDG-PET/CT images in patients with breast cancer to determine whether PET/CT improved the level of diagnostic confidence as compared with PET and to compare PET/CT and CT findings at the location of suspected malignancies.Methods The study included 75 patients with known breast cancer. The initial PET/CT study for each patient was retrospectively reviewed to determine whether improved diagnostic confidence (IDC) regarding lesion localization and characterization was observed with PET/CT as compared with PET alone. PET/CT and CT findings were compared regarding lesion characterization and staging in 69 of the 75 patients, and in the case of discordant findings, comparison with histological or informative follow-up results was also performed.Results Fifty of the 75 patients exhibited increased FDG uptake in a total of 95 regions. In the comparison of PET/CT and PET, PET/CT resulted in IDC in 30 (60%) of these 50 patients and in 52 (55%) of the 95 regions. In the comparison between PET/CT and CT in 69 patients, PET/CT demonstrated a significantly better accuracy than CT (P<0.05). PET/CT showed definitely positive findings in 60 regions with malignancies, among which CT exhibited positive findings in 43 (72%). PET/CT and CT accurately staged 59 (86%) and 53 (77%) of the 69 patients, respectively.Conclusions PET/CT added incremental diagnostic confidence to PET in more than 50% of patients and regions with increased FDG uptake. PET/CT accurately detected more regions with malignancies than did CT. This initial evaluation suggests that PET/CT is preferable to PET or CT in the diagnosis of breast cancer.     

TNM staging with FDG-PET/CT in patients with primary head and neck cancer

Purpose PET/CT, PET+CT, and CT were compared concerning accuracies in TNM staging and malignancy detection in head and neck cancer. The impact of PET/CT compared to the other imaging modalities on therapy management was assessed. Materials and methods Fifty-five patients with suspected head and neck primary cancer underwent whole-body FDG-PET/CT. PET/CT and PET+CT were evaluated by a nuclear medicine physician and a radiologist; CT was evaluated by two radiologists, PET by two nuclear physicians. Histopathology served as the standard of reference. Differences between the staging modalities were tested for statistical significance by McNemar’s test. Results Overall TNM-staging and T-staging with PET/CT were more accurate than PET+CT and CT alone (p < 0.05). PET/CT was marginally more accurate than CT alone in N-staging (p = 0.04); no statistically significant difference was found when compared to PET+CT for N-staging. PET/CT altered further treatment in 13 patients compared to CT only and in 7 patients compared to PET+CT. Conclusion Combined PET/CT proved to be partly more accurate in assessing the overall TNM-stage than CT and PET+CT. These results were based on a higher accuracy concerning the T-stage, mainly in patients with metallic implants and marginally the N-stage. Therapy decisions have been influenced in a substantial number of patients. PET/CT might be considered as a first line diagnostic tool in patients with suspected primary head and neck cancer.     

Revealing hepatic metastases from colorectal cancer: value of combined helical CT during arterial portography and CT hepatic arteriography with a unified CT and angiography system

OBJECTIVE: The purpose of our study was to evaluate the use of combined helical CT during arterial portography and CT hepatic arteriography in the preoperative assessment of hepatic metastases from colorectal cancer using a unified CT and angiography system. MATERIALS AND METHODS: Fifty-four patients with hepatic metastases from colorectal cancer preoperatively underwent combined CT during arterial portography and CT hepatic arteriography using the unified CT and angiography system. Three radiologists independently and retrospectively reviewed the images of CT during arterial portography alone, CT hepatic arteriography alone, and combined CT during arterial portography and CT hepatic arteriography. Image review was conducted on a segment-by-segment basis; a total of 432 hepatic segments with (n = 103) 118 metastatic tumors ranging in size from 2 to 160 mm (mean, 25.8 mm) and without (n = 329) tumor were reviewed. RESULTS: Relative sensitivity of combined CT during arterial portography and CT hepatic arteriography (87%) was higher than that of CT during arterial portography alone (80%, p < 0.0005) and CT hepatic arteriography alone (83%, p < 0.005). Relative specificity of CT hepatic arteriography alone (95%, p < 0.0005) and combined CT during arterial portography and CT hepatic arteriography (96%, p < 0.0001) was higher than that of CT during arterial portography alone (91%). Diagnostic accuracy, determined by a receiver operating characteristic curve analysis, was greater with combined CT during arterial portography and CT hepatic arteriography than with CT during arterial portography alone (p < 0.05) or CT hepatic arteriography alone (p < 0.01). CONCLUSION: Using a unified CT and angiography system, we found that combined CT during arterial portography and CT hepatic arteriography significantly raised the detectability of hepatic metastases from colorectal cancer.     

Reducing radiation dose in rest-stress cardiac PET/CT by single poststress cine CT for attenuation correction: quantitative validation.

Cardiac PET/CT is optimized by cine CT with dedicated shift software for manual correction of attenuation-emission misregistration. Separate rest and stress CT scans incur greater radiation dose to patients than does standard helical PET/CT or "pure" PET using rotating rod attenuation sources. To reduce radiation dose, we tested quantitative accuracy of using a single poststress cine CT attenuation scan for reconstructing rest perfusion images to eliminate resting CT attenuation scans. METHODS: A total of 250 consecutive patients underwent diagnostic rest-dipyridamole myocardial perfusion PET/CT with (82)Rb and a 16-slice PET/CT scanner using averaged cine CT attenuation data during breathing at rest and stress. After correcting for any attenuation-emission misregistration, we quantitatively compared resting perfusion images reconstructed using rest cine CT attenuation data with the same resting emission data reconstructed with poststress cine CT attenuation data. Automated software quantifying average regional quadrant activity, severity, size, and combined size and severity of perfusion defects was used for this comparison. RESULTS: Resting perfusion images reconstructed using rest cine CT attenuation data were quantitatively comparable to resting images reconstructed with poststress cine CT attenuation data with no clinically significant differences. Twenty-five (10%) of 250 cases required shifting of stress cine CT attenuation data to achieve optimal attenuation-emission coregistration with resting perfusion data. Eliminating rest CT attenuation scans reduced CT radiation dose by 50% below rest-plus-stress cine CT protocols. CONCLUSION: Resting perfusion images reconstructed using poststress cine CT attenuation data are quantitatively comparable to resting images reconstructed with resting cine CT attenuation data. Eliminating the rest CT scan reduces CT radiation dose by 50%.     

Evaluation of non-contrast-enhanced CT in blunt abdominal trauma]

We compared the findings of noncontrast-enhanced CT with those of contrast-enhanced CT in 126 patients with blunt abdominal trauma to evaluate the usefulness of noncontrast-enhanced CT. In 112 of the patients, visceral injuries were confirmed by surgery or clinical follow-up including CT. Although noncontrast-enhanced CT diagnosed all patients with 12 intestinal injuries requiring immediate surgery, contrast-enhanced CT missed two of these patients because high density hematomas on noncontrast-enhanced CT became isodense after IV administration of contrast material. However, contrast-enhanced CT was superior to noncontrast-enhanced CT in the diagnosis of hepatic and renal injuries. A case of renal artery occlusion was only visualized on contrast-enhanced CT. We conclude that both noncontrast- and contrast-enhanced CT should be performed for the CT evaluation of blunt abdominal trauma.     

Survey of conventional and spiral ct doses

PURPOSE: To investigate the radiation dose for conventional computed tomography (CT) and spiral CT during different CT examinations at various hospitals and practices. MATERIALS AND METHODS: CT dose index with an active length of 15 cm was measured in 16 different types of CT scanners by using ionization chamber dosimetry. Twenty-six holders (one who has legal responsibility under national law for a radiologic installation) operating a total of seven conventional and 20 spiral CT scanners were asked for their standard parameters for various CT examinations. Weighted CT dose index and dose-length product were determined for each examination. RESULTS: For most examinations, the tube current time product was significantly higher for conventional CT than for spiral CT (.002 相似文献   

螺旋CT机的CT值均匀性检测方法的探讨

目的 探讨影响CT值均匀性检测标准的因素，并提出改进意见。方法 通过改变模体条件和CT扫描条件，获得2台不同类型CT机的均匀性，观察影响均匀性检测标准的因素。结果 用头部条件扫描，模体未包铝环时，普通CT机的均匀性优于有软件校正功能的多层螺旋CT机；包铝环后，恰好相反用体部条件扫描时，2种类型的CT机相差不大。结论在CT值均匀性检测时，若采用头部条件进行扫描时应考虑颅骨的影响，在对带有预校正功能的CT机进行检测时，应在模体四周绕1圈约2mm厚的铝环；若不加铝环直接进行CT值均匀性检测时应采用体部条件扫描。     

Respiration artifacts in whole-body 18F-FDG PET/CT studies with combined PET/CT tomographs employing spiral CT technology with 1 to 16 detector rows

Purpose Co-registration accuracy in combined whole-body (WB) PET/CT imaging is impaired by respiration-induced mismatches between the CT and the PET. Furthermore, PET/CT misregistration may bias the PET tracer distribution following CT-based attenuation correction (CT-AC). With the introduction of multi-row CT technology of up to 16 detector rows into PET/CT designs, we investigated the incidence of respiration artifacts in WB PET/CT examinations of patients who were unable to follow any breath-hold instructions.Methods A total of 80 WB studies from six international sites operating PET/CT tomographs with 1-, 2-, 4-, 6-, 8-, and 16-row spiral CT were included. PET/CT examinations were acquired with the patients breathing normally during both the CT and the PET scan, and CT-AC was performed routinely. All studies were anonymized and reviewed independently by three radiologists and three nuclear medicine specialists. We report the frequency and severity of artifacts on CT and PET for the thorax and the abdomen.Results In WB PET/CT imaging of normally breathing patients, significant gains in diagnostic image quality can be expected from employing CT technology with six or more detector rows. In our study, fewer PET images appear distorted than corresponding CT images, which is due to the limited propagation of only mild CT image artifacts after the resampling of the CT-based attenuation map during CT-AC.Conclusion In whole-body PET/CT imaging of normally breathing patients, respiration-induced artifacts are reduced in both magnitude and prominence for PET/CT systems employing CT components of six or more detector rows.     

Single versus multi-detector row CT: comparison of radiation doses and dose profiles

RATIONALE AND OBJECTIVES: The purpose of this study was twofold: (a) to compare the radiation dose profile between computed tomography (CT) with a single detector row (SD) and with a multi-detector row (MD) and (b) to compare specific organ doses between SD CT and MD CT. MATERIALS AND METHODS: Thermoluminescent dosimeters placed within a 32-cm-diameter cylindrical phantom were used to measure and compare dose profiles from one SD CT scanner and from one MD CT scanner. SD CT scanning parameters were 210 mA, 140 kVp, pitch of 1.0, 5-mm section thickness, and 0.8-second gantry rotation speed. MD CT scanning parameters were 130 mA, 140 kVp, pitch of 0.75, 4 x 5-mm section thickness, 15-mm table feed, and 0.8-second gantry rotation speed. To plot radiation dose profile, doses were measured both in the imaging plane and in the area adjacent to the imaging plane. The resultant data were normalized to achieve constant image noise between MD CT and SD CT. Direct doses to individual organs from primary and scattered radiation were measured with an anthropomorphic phantom containing thermoluminescent dosimeters and with a standard pelvic imaging protocol for both MD CT and SD CT. RESULTS: MD CT resulted in a dose profile approximately 27% higher than that from SD CT in the plane of imaging (8.0 vs 6.3 mGy) and 69% higher adjacent to the plane of imaging (6.8 vs 4.0 mGy). The individual doses to the kidneys, uterus, ovaries, and pelvic bone marrow were 92%-180% higher with MD CT than with SD CT. CONCLUSION: With image noise constant between SD CT and MD CT, the radiation dose profile both inside and outside the plane of imaging was higher with MD CT than with SD CT. Organ dose also was higher with MD CT than with SD CT. This difference should be accounted for in the design of MD CT protocols, especially as MD CT technology becomes more widely available for clinical use.