侵袭性和非侵袭性胸腺瘤的CT特征

胸腺瘤是前纵隔常见的原发性肿瘤，是胸腺的内皮性肿瘤，大多数的胸腺肿瘤有完整的包膜，但是有部分侵袭性胸腺瘤包膜不完整和可以侵袭周围邻近组织，由于愈后不同，在治疗前鉴别侵袭性胸腺瘤和非侵袭性胸腺瘤，对手术、放疗、化疗的方案的制定是极为重要的。本研究通过分析侵袭性胸腺瘤和非侵袭性胸腺瘤的CT表现及特征，为鉴别侵袭性胸腺瘤和非侵袭性胸腺瘤提供依据，现报告如下。     

侵袭性胸腺瘤的CT诊断

本文回顾分析9例经病理证实的侵袭性胸腺瘤的CT表现,以期提高对该病的诊断水平. 1 材料与方法 1.1 临床资料 收集侵袭性胸腺瘤9例,其中男性8例,女性1例,年龄50～73岁,平均年龄为63岁.9例侵袭性胸腺瘤,合并重症肌无力6例,上腔静脉综合征2例,其他临床表现包括胸痛、胸闷7例,咳嗽、咯痰3例,无症状体检时发现纵隔肿块2例.所有的病例均经病理证实,其中5例经手术切除,4例经活检后病理证实.     

侵袭性胸腺瘤的CT诊断

本文对12例经病理及临床证实的侵袭性胸腺瘤CT表现进行回顾性分析,旨在提高侵袭性胸腺瘤的检出率及对良恶性胸腺瘤的鉴别,总结如下. 1 材料与方法     

CT findings of malignant lymphoma of the anterior mediastinum--differentiation from invasive thymoma

CT findings were compared retrospectively between 9 cases with malignant lymphoma of the anterior mediastinum and 8 cases with invasive thymoma. CT findings of malignant lymphoma were as follows: 1) The majority of the tumors were bilateral and extended beyond the anterior mediastinum to the other mediastinum compartments. 2) Their margin was either smooth or lobulated. 3) Their density was either homogeneous or heterogeneous. In the case with heterogeneous density, ring, triangle and/or band-like low density areas, just like interspace of fused lymph nodes, were demonstrated. Calcification or cysts could not be shown. 4) Patent inherent vessels without deviation were occasionally demonstrated running through the tumors. 5) The tumors faced and contacted widely to anterior chest wall and often pressed the lung laterally at the anterior parietomediastinal pleural reflection. 6) Pleural implants were not demonstrated.     

Imaging of a thymoma incidentally detected by C-11 choline PET/CT

The integrated modality positron emission tomography/computed tomography (PET/CT) with C-11 choline is an established diagnostic tool for restaging prostate cancer patients with a biochemical failure after primary treatment. Thymoma is a rare tumor originating in thymus epithelial cells, asymptomatic in one-third to one-half of patients, and often occurring in the fourth and fifth decades of life. In the present case, C-11 choline PET/CT was performed in a prostate cancer patient with a biochemical relapse, to restage the disease. In addition to the detection of local recurrent disease in prostatic fossa, an abnormal C-11 choline increased uptake in mediastinum was reported. The mediastinal finding was initially wrongly interpreted by clinicians as a lymph nodal metastasis from prostate cancer. However, histopathological analysis confirmed the presence of a thymoma. Although rare, thymoma has to be considered as differential diagnosis in case of mediastinal masses presenting C-11 choline PET/CT positive findings, to avoid inappropriate patient management.     

恶性胸腺瘤的CT与MRI诊断

目的：分析侵袭性胸腺瘤及胸腺癌的CT及MRI表现，探讨其鉴别诊断要点。方法：复习经病理组织学证实的18例侵袭性胸腺瘤及9例胸腺癌的CT、MRI所见，重点观察肿瘤的大小、密度、边缘改变，对周围纵隔结构的侵犯。结果：18例侵袭性胸腺瘤、9例胸腺癌CT、MRI均表现为前纵隔不规则软组织肿块。前者肿瘤直径大于8cm者15例（83％），病灶内密度及信号不均匀12例。心血管受侵16例，后者肿块直径在8cm以上者7例（77.8％),肿块内密度及信号不均6例，心知管受累8例，纵隔肺门淋巴结转移1例，肺内转移3例，双侧肾上腺及肝脏转移1例。结论：虽然侵袭性胸腺瘤和胸腺癌的影像学表现相似，但胸腺癌更具有侵袭性，胸外转移常见，病理组织学检查有助于两者的鉴别。     

恶性胸腺瘤WHO病理分类及其CT表现

目的:分析恶性胸腺瘤的CT表现,以便于分类、分期和选择治疗。方法:分析21例手术及病理证实的WHO分类恶性胸腺瘤的CT表现,与手术病理相对照。结果:恶性胸腺瘤WHO分类B1型3例,B2型6例,B3型4例,C型(胸腺癌)8例。CT表现:心脏大血管受侵11例,主要表现肿块的心脏大血管接触面(mass-cardiovascular inferface,MCI)呈灌铸型生长。纵隔胸膜-肺受侵13例,主要表现为肿块-肺接触面(mass-pulmonary interface,MPI)增厚呈尖角或锯齿征。胸膜种植3例。肺门、肺内转移4例。C型(胸腺癌)更具侵袭性,远处转移多见。结论:CT能准确显示恶性胸腺瘤周围侵犯范围、胸膜种植及远隔转移。可准确分期和决定治疗方案,并对分类及预后作出评估。     

Nuclear Imaging for Cardiac Amyloidosis: Bone Scan,SPECT/CT,and Amyloid-Targeting PET

Cardiac amyloidosis (CA) is a type of systemic amyloidosis, in which abnormal amyloid fibril is deposited in extracellular space of myocardium. Most common subtypes of CA are amyloidosis of immunoglobulin light chain (AL) and amyloidosis of transthyretin (ATTR). With increase in incidence of CA and development of new drugs, the needs of early and accurate diagnosis of CA are increasing. In CA, bone scan and SPECT/CT have long been used for diagnosis. Currently, bone scan is included in almost all practice guidelines as one of key diagnostic examinations for ATTR CA. In some specific scenarios, bone scan can be used as even a substitute for endomyocardial biopsy. Recently, amyloid-targeting PET that is used for Alzheimer dementia has also been attempted as an imaging method for CA. Although the study results are still insufficient, amyloid-targeting has shown promising potential as an imaging method for CA, particularly in AL. Here, imaging method and clinical application and implication of bone scan, SPECT/CT, and amyloid-targeting PET/CT in CA are reviewed.     

侵袭性和非侵袭性胸腺瘤的CT鉴别诊断

目的 :评价CT对侵袭性和非侵袭性胸腺瘤的鉴别诊断价值。方法 :由两位放射科医师采用双盲法对 2 9例侵袭性胸腺瘤和 2 4例非侵袭性胸腺瘤进行单独评价 ,分析CT诊断侵袭性或非侵袭性胸腺瘤的可靠性 ,并与手术病理结果对照。结果 :侵袭性胸腺瘤 ( 2 1例 ,占 72 %)较非侵袭性胸腺瘤 ( 7例 ,占 2 9%)有明显的分叶 (P <0 .0 5 )。侵袭性胸腺瘤囊变率 ( 2 3例 ,占 79%)较非侵袭性胸腺瘤 ( 6例 ,占 2 3 %)高 (P <0 .0 1) ;侵袭性胸腺瘤增强后较非侵袭性胸腺瘤有明显强化。结论 :肿瘤边缘分叶或不规则、囊变或坏死、增强前后CT值相差 2 0HU、纵隔脂肪线消失等CT征象提示侵袭性胸腺瘤。     

Thoracic actinomycosis: CT features with histopathologic correlation

OBJECTIVE: Thoracic actinomycosis is a chronic suppurative pulmonary or endobronchial infection caused by Actinomyces israelii, a gram-positive anaerobic organism. We present the CT features of thoracic actinomycosis with histopathologic correlation. CONCLUSION: The typical CT feature of parenchymal actinomycosis is a chronic segmental air-space consolidation containing necrotic low-attenuation areas with frequent cavity formation. A broncholith can be secondarily infected with Actinomyces organisms, resulting in endobronchial actinomycosis. It usually manifests as a proximal endobronchial calcification associated with distal obstructive pneumonia.     

Asymptomatic adnexal masses: correlation of FDG PET and histopathologic findings

PURPOSE: To analyze asymptomatic adnexal masses at positron emission tomography (PET) with fluorodeoxyglucose (FDG) in correlation with histopathologic findings and evaluate FDG PET for assessing malignancy in comparison with transvaginal B-mode and Doppler ultrasonography (US) and magnetic resonance (MR) imaging. MATERIALS AND METHODS: Ninety-nine patients underwent static FDG PET of the abdomen. US scans were evaluated according to sonomorphologic scoring systems. Resistance index of tumor blood vessels was calculated. Transverse and sagittal T1-weighted MR images obtained before and after intravenous administration of gadopentetate dimeglumine with a fat-saturation technique and T2-weighted MR images were acquired at 1.5 T. Adnexal mass malignancy was first assessed with each modality and then with a combination of the three techniques. Final diagnosis was made with histopathologic evaluation. RESULTS: FDG PET depicted seven of 12 malignant and 66 of 87 benign asymptomatic adnexal tumors. False-negative PET results were obtained in five of seven stage pT1a cystadenocarcinomas and tumors of low malignant potential but not in advanced-stage ovarian carcinomas. Small moderately intense FDG accumulations in the lower pelvis were caused by benign adnexal tumors or gastrointestinal activity in 21 of 27 cases. The overall sensitivities and specificities were 58% (95% CI: 27.7, 84.8) and 76% (95% CI: 65.5, 84.4), respectively, for FDG PET; 92% (95% CI: 61.5, 99.8) and 60% (95% CI: 48.7, 70.1), respectively, for US; 83% (95% CI: 51.6, 97.7) and 84% (95% CI: 74.5, 90.9), respectively, for MR imaging; and 92% (95% CI: 61.5, 99.8) and 85% (95% CI: 75.8, 91.8), respectively, for the combination of three modalities. CONCLUSION: Since the sensitivity of US is as high as that of PET, MR imaging, and the combination of three modalities, it remains the method of choice for diagnosis and assessment of asymptomatic adnexal masses.     

Intracaval and intracardiac extension of malignant thymoma: CT diagnosis

There is disagreement about the ability of CT to detect isolated invasion of mediastinal vessels by malignant thymoma. Diagnosis usually depends on the absence of intact fat planes between the tumor mass and the adjacent vessel. We describe a rare case of CT demonstration of direct intraluminal invasion of a malignant thymoma into the superior vena cava and the right atrium.     

侵袭性胸腺瘤CT表现与诊断价值

目的 探讨侵袭性胸腺瘤CT表现特征.方法 经病理证实的15例侵袭性胸腺瘤均行CT平扫加增强检查,分别对病变的形态、密度、强化方式、周围结构侵犯及种植情况进行回顾性分析.结果 15例肿瘤均表现为边缘分叶、不规则,密度不均,平扫CT值40～50HU,其中坏死囊变11例,点状钙化4例;15例均有纵隔结构侵犯,周围脂肪间隙模糊、消失,其中大血管侵犯9例,心包侵犯（心包积液）5例,胸膜肺界面不清8例,胸腔积液6例;增强扫描见肿瘤实质部分呈轻至中度强化,CT值增加10～20HU,坏死囊变不强化.结论 侵袭性胸腺瘤CT表现具有一定特征,螺旋CT能显示肿瘤内部改变,又能显示周围组织受侵犯情况,具有较高诊断价值.     

Mucin-producing pancreatic tumor: CT findings and histopathologic correlation.

Twenty patients with mucin-producing pancreatic tumor and 60 with other pancreatic diseases underwent computed tomography (CT) to establish the CT characteristics of mucin-producing pancreatic tumor. Scans were obtained with thin sections by administering a large volume of contrast material (200 mL). Mucin-producing pancreatic tumors were divided into three subgroups, and the CT characteristics were as follows: Main duct type tumors consisted of a cystic mass in or communicating with the dilated main pancreatic duct (MPD). Excrescent nodules and/or septa were found in the cyst. The MPD was markedly dilated over its entire length. Branch duct type tumors consisted of clustered small cysts that were all approximately the same size in diameter (1-2 cm). Excrescent nodules or septa were not always seen. The MPD near the lesion was often slightly dilated. Peripheral type tumors consisted of a well-defined cystic mass with excrescent nodules and/or septa. Even if the cyst was multilocular, a large main cyst was in it. The MPD usually was not dilated. The CT findings corresponded to macroscopic findings. Mucin-producing pancreatic tumor can be differentiated from other pancreatic diseases with these criteria.     

Value of 11C-choline PET and contrast-enhanced CT for staging of bladder cancer: correlation with histopathologic findings.

Lymph node involvement is a major prognostic factor in bladder cancer, but the accuracy of conventional imaging modalities for the prediction of regional and distant metastatic diseases is limited. This study was performed to compare the diagnostic accuracies of contrast-enhanced CT and PET with (11)C-choline for the staging of urothelial bladder cancer. METHODS: Twenty-seven patients (median age, 69.1 y) who had urothelial bladder cancer and who were referred for radical cystectomy and pelvic lymph node dissection (PLND) on the basis of a histologic evaluation after transurethral resection of bladder cancer (TURB) were studied. PET scanning, using 2 multiring whole-body tomographs, was performed 5 min after intravenous injection of approximately 370-500 MBq of (11)C-choline. In addition, conventional bone scintigraphy and contrast-enhanced CT were performed. After imaging, cystectomy and PLND were performed in all patients. Pathologic (11)C-choline uptake that could not be explained by intestinal activity was noted as a positive result. Node positivity was determined by size on CT: nodes measuring more than 1 cm in the long axis were described as being positive for tumor. Histopathologic findings were used as a reference. RESULTS: The presence of residual bladder cancer (pTa-pT4) was correctly detected in 21 of 25 histologically tumor-positive patients (84%) by CT and in 24 of 25 patients (96%) by (11)C-choline PET. Lymph node involvement was correctly detected in 4 of 8 patients (50%) by CT and in 5 of 8 patients (62%) by (11)C-choline PET. The median size of the 3 nodes with false-negative PET results was 9 mm (range, 6-21 mm), and the median size of the metastatic lesions within the lymph nodes was 3 mm (range, 1-15 mm). CT resulted in 6 (22%) false-positive lymph nodes, whereas none was demonstrated by (11)C-choline PET; these data indicated a significantly higher accuracy of PET than of CT (P < 0.01). Both modalities missed a small peritoneal metastasis verified by histologic evaluation. No positive results were obtained from bone scintigraphy. CONCLUSION: These preliminary data suggest that (11)C-choline PET is comparable to CT for detecting residual bladder cancer after TURB but appears to be superior to CT for the evaluation of potential additional lymph node metastases. (11)C-choline PET should be further evaluated for staging in patients who have bladder cancer and who are scheduled for radical cystectomy.     

Parotid gland oncocytosis: CT findings with histopathologic correlation

Oncocytic neoplasms result from metabolically altered cells that accumulate abundant mitochondria within their cytoplasm by oncocytic metaplasia. In this report, the CT findings are described and correlated with the histopathologic features of a case of oncocytoma involving the parotid gland that arose in a background of nodular oncocytic hyperplasia. When imaging demonstrates multiple small nodules in the parotid gland with a large, solid, or cystic mass, the diagnosis of oncocytic neoplasia should be considered.