Enhancement characteristics of papillary renal neoplasms revealed on triphasic helical CT of the kidneys.

OBJECTIVE: The purpose of this study was to determine whether renal tumor enhancement or heterogeneity on triphasic helical CT scans is predictive of the papillary cell subtype or nuclear grade of renal cell carcinoma. MATERIALS AND METHODS: We reviewed the CT scans of 90 consecutive patients with renal masses who had undergone triphasic renal helical CT before a complete or partial nephrectomy (12 with papillary renal cell carcinomas, 66 with nonpapillary renal cell carcinomas, and 12 with benign lesions). Three radiologists who were unaware of the patients' diagnoses retrospectively and independently measured the attenuation of each patient's tumor, abdominal aorta, and normal renal parenchyma on the scans obtained during all three phases. Ratios of tumor-to-aorta enhancement and tumor-to-normal renal parenchyma enhancement were calculated for both of the phases performed after contrast material had been administered. Tumor heterogeneity was calculated as the difference between the highest and lowest attenuation values divided by the value of the enhancement of the aorta. Values were correlated with cell type and nuclear grade found at surgical pathology. RESULTS: Low tumor-to-aorta enhancement and low tumor-to-normal renal parenchyma enhancement ratios on the vascular phase scans significantly correlated (p < 0.001) with papillary renal cell type carcinoma. Homogeneity and tumor-to-parenchyma enhancement ratios on the parenchymal phase scans also significantly correlated (p < 0.001) with papillary renal cell type carcinoma. Heterogeneity and tumor enhancement ratios did not correlate with the nuclear grade of the carcinoma. CONCLUSION: Papillary renal cell carcinomas are typically hypovascular and homogeneous. A high tumor-to-parenchyma enhancement ratio (> or = 25%) essentially excludes the possibility of a tumor being papillary renal cell carcinoma. A low tumor-to-aorta enhancement ratio or tumor-to-normal renal parenchyma enhancement ratio is more likely to indicate papillary renal cell carcinoma.     

Pancreatic-phase versus portal vein-phase helical CT of the pancreas: optimal temporal window for evaluation of pancreatic adenocarcinoma

OBJECTIVE: Our objective was to use helical CT to compare the enhancement attenuation values of pancreatic adenocarcinoma, adjacent normal pancreas, and critical vascular structures during the pancreatic phase and portal vein phase. SUBJECTS AND METHODS: Forty-one patients with pathologically proven pancreatic adenocarcinoma underwent dual-phase thin-section dynamic helical CT using a pancreatic-phase and portal vein-phase protocol. The scan delay after initiation of the contrast bolus was 40 sec for the pancreatic phase and 70 sec for the portal vein phase. Attenuation values after i.v. contrast administration were calculated during both phases of scanning for normal pancreas, pancreatic tumor, celiac axis, superior mesenteric artery, superior mesenteric vein, splenic vein, and portal vein. Quantitative values were assessed using regions of interest. RESULTS: Mean differences of enhancement between tumor and normal pancreas were significantly greater in the pancreatic phase (57 H) than the portal vein phase (35 H) (p = .0001). Enhancement values of all the critical vascular structures were also significantly greater in the pancreatic phase than the portal vein phase (p < .001). CONCLUSION: With dynamic thin-section helical CT, pancreatic-phase scanning provides greater differences in contrast enhancement between normal pancreas and pancreatic tumor and between pancreatic tumors and surrounding critical vascular structures than does portal vein-phase scanning.     

功能性小胰岛细胞瘤的CT定位诊断

目的：评价功能性小胰岛细胞瘤的ＣＴ术前定位价值。材料和方法：６例手术证实的功能性小胰岛细胞瘤的病人，术前行电子束ＣＴ增强动静脉双期扫描，测量肿瘤与胰腺实质的ＣＴ值并进行配对ｔ检验。结果：增强动脉期肿瘤显示较静脉期清晰。结论：动脉期ＣＴ扫描对胰岛细胞瘤的定位价值较大。     

螺旋CT多期扫描对肾细胞癌的诊断价值

目的探讨CT在肾细胞癌诊断中的价值。方法回顾性分析22例经手术、病理证实的肾细胞癌CT表现。结果 CT平扫中5例病灶呈等密度或稍低密度,15例为混杂密度,2例为稍高密度。增强扫描皮质期18例明显强化,4例中等度强化,强化均匀或不均匀。肾实质期所有病灶强化迅速减退,肾盂期病灶强化进一步减低。其中8例肾癌出现肾周邻近脏器侵犯及淋巴结转移。结论肾细胞癌的CT表现具有一定特征性,CT对肾细胞癌的诊断具有很高的价值。     

Detection of small pancreatic tumors with multiphasic helical CT

OBJECTIVE: The purpose of this study was to evaluate the sensitivity and specificity of helical CT in the detection of adenocarcinomas of the pancreas measuring 2 cm or smaller at pathologic examination. MATERIALS AND METHODS: Thin-section triple phase (20, 40, and 70 sec after the start of injection) contrast-enhanced helical CT scans of the abdomen in 18 patients with a pancreatic carcinoma that was 2 cm or smaller and 18 patients with a normal pancreas were retrospectively reviewed by two senior radiologists who specialized in oncologic abdominal imaging. Discrepancies were resolved by consensus. The observers were unaware of the clinical information. CT scans were evaluated for the presence of a pancreatic mass, bile, and pancreatic duct stricture. The location and size of tumors as determined on CT were compared with pathologic findings. The CT results were also compared with the prospective CT interpretations derived from the radiology reports and with the endoscopic sonographic reports when available. RESULTS: The sensitivity of thin-section triple-phase helical CT in the detection of small pancreatic masses was 77%, and the specificity was 100% for the two experienced observers. The sensitivity and specificity were 72% and 100%, respectively, for the prospective interpretations done by 10 observers. There was no correlation between the tumor size at pathology and the CT measurements. CONCLUSION: Thin-section contrast-enhanced helical CT is sensitive and highly specific for the detection of pancreatic tumors measuring 2 cm or smaller. Improvement in the detection rate of this technique compared with previous techniques lies in the optimization of parenchymal enhancement during the pancreatic phase and the decrease in slice thickness.     

无功能胰岛细胞瘤的CT诊断

目的：探讨无功能胰岛细胞瘤的CT表现。方法：回顾性分析9例经手术和病理证实的无功能胰岛细胞瘤的CT表现。9例均行电子束CT动静脉双期扫描,1例行多幅流动扫描。测量胰腺和肿瘤动静脉双期的CT值。结果：9例无功能胰岛细胞瘤中5例位于胰头,3例位于胰尾,1例位于胰颈。8例肿瘤有程度不同的强化,1例因囊变和出血无强化。4例肿瘤动脉强化积度高于静脉期,3例与静脉期相同,1例低于静脉期。与胰腺实质比较,3例为高密度肿块,2例为等密度,4例为低密度。2例肿瘤内可见局限性钙化,4例伴胰管扩张。1例出现肝脏内多发性低密度转移灶。结论：无功能胰岛细胞瘤多表现为边界清晰的较大的肿块,多数肿瘤有程度不同的强化,瘤内多有坏死、囊变、出血和钙化。     

螺旋CT对肾细胞癌亚型的鉴别诊断价值

目的:探讨CT动态增强扫描对肾细胞癌病理亚型的鉴别诊断价值。方法:87例经手术病理证实的肾细胞癌患者,包括50例透明细胞癌、17例乳头状癌、8例嫌色细胞癌和2例集合管癌,术前行CT平扫和双期动态增强扫描(肾皮髓期和肾实质期),测量肿瘤、腹主动脉及邻近正常肾实质的CT值,并计算肿瘤与主动脉、肾实质的强化比值,同时评价肿瘤的强化方式,对不同病理亚型肿瘤的各项指标进行统计学分析。结果:透明细胞癌在皮髓期和实质期增强扫描时肿瘤与主动脉、肾实质的强化比值均高于乳头状癌和嫌色细胞癌(P<0.01),而乳头状癌和嫌色细胞癌间差异均无统计学意义(P>0.05)。不均匀强化常见于透明细胞癌(92%)、乳头状癌(82.4%)和集合管癌(100%);而均匀强化常见于嫌色细胞癌(62.5%),其与透明细胞癌(P=0.010)和乳头状癌(P=0.017)间差异有显著性意义。结论:CT增强扫描时分析肿瘤与主动脉和肾实质的强化比值及强化的均匀度对肾癌病理亚型的鉴别诊断有重要价值。     

电子束CT双期扫描定量估价胰腺增强程度

目的：定量估价电子束ＣＴ双期扫描胰腺的增强程度。材料和方法：１１０例可疑胰腺病变者（２６～７２岁）均行电子束ＣＴ检查。其中胰腺癌１５例，胰腺炎３例，胰腺外伤２例，正常胰腺９０例。应用高压注射器以３．５ｍｌ／秒（８０ｍｌ）和１０ｍｌ／秒（２０ｍｌ）速度注射Ｕｌｔｒａｖｉｓｔ１００ｍｌ，在注射造影剂后１８～２０秒和５５～６０秒，应用ＳＶＳ０．３秒序列扫描胰腺２０层，层厚６ｍｍ。于动静脉期测量胰腺头、体、尾ＣＴ值。结果：在动脉期胰腺增强的ＣＴ值为１０１Ｈｕ±８（标准差），静脉期为８１Ｈｕ±５。其中６１例（５５％）动脉期较静脉期ＣＴ值增高２０Ｈｕ以上；３８例（３４％）增高１０Ｈｕ以上；１１例（１０％）动脉期ＣＴ值低于静脉期。结论：胰腺动脉期扫描较静脉期可提供更详细的解剖结构，可更清楚显示胰腺癌对胰周的浸润，可提高检测胰腺内小病灶的准确性。     

Multi--detector row helical CT of the pancreas: effect of contrast-enhanced multiphasic imaging on enhancement of the pancreas, peripancreatic vasculature, and pancreatic adenocarcinoma.

PURPOSE: To determine the optimal phase for enhancement of the normal pancreas and peripancreatic vasculature and the maximal tumor-to-pancreatic parenchymal enhancement difference by using multiphase, contrast material-enhanced, multi-detector row helical computed tomography (CT). MATERIALS AND METHODS: Forty-nine patients with a normal-appearing pancreas but suspected of having pancreatic abnormality and 28 patients with proved pancreatic adenocarcinoma underwent multiphase, contrast-enhanced, multi-detector row CT during the arterial phase (AP), pancreatic parenchymal phase (PPP), and portal venous phase (PVP). Attenuation values of the normal pancreas, pancreatic adenocarcinoma, celiac and superior mesenteric arteries, and superior mesenteric and portal veins were measured during all three imaging phases. Quantitative analysis of these measurements and subjective qualitative analysis of tumor conspicuity were performed. RESULTS: Maximal enhancement of the normal pancreatic parenchyma occurred during the PPP. Maximal tumor-to-parenchyma attenuation differences during the PPP and PVP were equivalent but greater than that during the AP. Subjective analysis revealed that tumor conspicuity during the PPP and PVP was equivalent but superior to that during the AP. Maximal arterial enhancement was seen during the PPP, and maximal venous enhancement was seen during the PVP. CONCLUSION: A combination of PPP and PVP imaging is sufficient for detection of pancreatic adenocarcinoma, because it provides maximal pancreatic parenchymal and peripancreatic vascular enhancement. AP imaging can be reserved for patients in whom CT angiography is required.     

Differential diagnosis of hepatic tumors (hepatoma, hemangioma, and metastasis) with CT: value of two-phase incremental imaging.

Two-phase dynamic incremental CT is a technique in which CT scans are obtained 45 sec and 6 min after commencing the rapid bolus injection of contrast medium. We analyzed the contrast enhancement patterns of three types of hepatic tumors (72 hepatomas, 39 hemangiomas, and 28 metastases) in 139 patients to determine if any differences in the patterns are useful in the differential diagnosis of these lesions. Dynamic incremental CT scanning was performed after 100 ml of iodinated contrast material was administered i.v. with a power injector at a rate of 2 ml/sec. A 1-sec scanning time was used with a 1.6-sec inter-scan delay, which allowed table motion between scans. CT scans (eight to 16 sections) were obtained 45-110 sec (early phase) and 6-7 min (delayed phase) after commencing the injection of contrast medium. The enhancement patterns of hepatomas were as follows: 32% were totally hyperdense in the early phase and totally hypodense in the delayed phase, while 24% were totally hypodense in both phases. Most of the hepatomas (88%) appeared as totally hypodense lesions in the delayed phase. In the case of hemangiomas, 56% were peripherally hyperdense in the early phase; in the delayed phase, 36% were isodense and 31% were totally hyperdense. Most hemangiomas (85%) were not totally hypodense in the early phase, and no hemangioma was totally hypodense in both phases. In the early phase, 61% of metastases were hypodense. In the delayed phase, 57% were hypodense. Metastases most commonly were totally hypodense in both phases (43%). We conclude that contrast enhancement patterns of hepatomas, hemangiomas, and metastases seen on two-phase dynamic incremental CT scans are useful in the differential diagnosis of these tumors.     

螺旋CT双期扫描对小胰头癌的诊断价值

目的探讨螺旋CT双期扫描对小胰头癌的诊断价值。方法18例经手术及病理证实的小胰头癌患,均行螺旋CT双期扫描,层厚3—10mm,螺距为1．0,注射造影剂后25s行动脉期扫描;60-70s行门脉期扫描。结果CT平扫13例肿瘤病灶为低密度,5例呈等密度,螺旋CT双期扫描均呈低密度改变,同时14例胰管有不同程度的扩张,8例胆总管扩张,5例血管周围脂肪内浸润。结论螺旋CT双期扫描对小胰头癌诊断有重要价值,并对小胰头癌的可切除性可做出准确的术前评价。     

胰腺癌CT诊断与鉴别诊断

目的评价CT平扫与增强扫描对胰腺癌的诊断与鉴别诊断价值.方法24例经手术病理或临床证实的胰腺疾病患者,包括胰腺癌(12)例,慢性胰腺炎(7例),胰腺转移瘤(2例),胰腺囊腺瘤(1例),胰腺结核(1例),以及胰头变异(1例),均经增强前与增强后CT扫描,并对全部病例的CT表现进行回顾性分析.结果24例胰腺病变患者中,恶性病变(胰腺癌与转移瘤)14例(58%),良性病变10例(42%).各种胰腺疾病的影像表现随其为良性或恶性病变而不同,例如,胰腺癌患者表现为瘤内的不均匀密度,增强扫描后病变无强化,而慢性胰腺炎患者则表现为病变密度均匀,增强扫描后病变均匀强化.结论CT扫描,尤其是CT增强扫描有助于将胰腺癌与其他胰腺疾病相鉴别.     

Imaging of uncommon tumors of the pancreas

In this article, the radiological manifestations of a variety of uncommon tumors of the pancreas are illustrated, with emphasis placed on their appearance at helical CT. Islet cell tumors, because of their vascularity, typically present as masses that are hyperattenuating to the normal pancreas at dual-phase helical CT. Lymphomas appear as hypoattenuating focal lesions or can diffusely infiltrate the gland. Absence of biliary tree dilatation, despite the presence of a bulky tumor, or associated extensive retroperitoneal adenopathy should offer clues to the diagnosis. Pancreatic metastases are usually seen in patients with advanced cancers, although isolated metastases from renal cell carcinoma can occurs years after the original tumor; such patients may benefit from surgical resection. Finally, the appearance of some rare neoplasms of mesenchymal origin is discussed.     

Dual-phase versus single-phase helical CT to detect and assess resectability of pancreatic carcinoma

OBJECTIVE: The aim of this study was to compare dual-phase and single-phase helical CT for the detection and assessment of resectability of pancreatic adenocarcinoma. SUBJECTS AND METHODS: We studied 60 patients (31 men, 29 women; age range, 31-84 years; mean age, 62 years) with suspected pancreatic malignancy. Patients were randomly assigned to one of two groups. For group A (n = 30), unenhanced scans through the liver and pancreas were followed by two separate acquisitions (dual-phase) at 20-25 and at 60-80 sec after IV contrast administration. For group B (n = 30), unenhanced scans were followed by one set of scans (single-phase) acquired caudocranially (from the inferior hepatic margin to the diaphragm) starting 50 sec after IV contrast administration. Two observers independently scored images for the presence of tumor and for assessment of tumor resectability. RESULTS: Comparison of dual-phase versus single-phase helical CT for tumor detection showed a diagnostic accuracy for observer 1 of 87% and 90%, respectively, and for observer 2, of 90% and 87%, respectively. For both helical CT techniques, the overall agreement between the two observers was 83% (kappa = 0.73 +/- 0.03) for single-phase helical CT and 90% (kappa = 0.89 +/- 0.03) for dual-phase helical CT. The assessment of resectability was affected by the low number of resectable tumors (n = 8). CONCLUSION: Single-phase helical CT is effective for the diagnosis and assessment of resectability of patients with suspected pancreatic carcinoma. Advantages are the lower radiation dose and fewer images to film and store.     

Small hypervascular hepatocellular carcinoma revealed by double arterial phase CT performed with single breath-hold scanning and automatic bolus tracking

OBJECTIVE: The purpose of this study was to evaluate the usefulness of double arterial phase CT for the detection of small hypervascular hepatocellular carcinomas, using an automated bolus-tracking technique to initiate the hepatic arterial phase CT. MATERIALS AND METHODS: Double arterial and late phase contrast-enhanced helical CT scans were obtained on 287 consecutive patients suspected of having hepatocellular carcinoma. These included 56 patients with 90 small (< or 3 cm) hepatocellular carcinomas and 50 patients with no hepatocellular carcinomas. CT scans of these patients were interpreted by three reviewers. The first arterial phase scan was initiated automatically 10 sec after the bolus-tracking program detected the threshold enhancement of 50 H in the abdominal aorta. Three reviewers interpreted the late phase CT scans in combination with the first, second, or both hepatic arterial phases. Measures of the reviewers' detection of hepatocellular carcinoma included analysis of interobserver variation, sensitivity, specificity, and area under receiver operating characteristic curve (A(z)). RESULTS: The time elapsed from bolus initiation to threshold aortic enhancement ranged from 10 to 24 sec (mean, 13 sec), resulting in initiation of the first arterial phase CT scan from 20 to 34 sec (mean, 23 sec). The combination of late phase CT and both first and second arterial phase images showed significantly better performance than the combination of the late phase and either the first or second arterial phases, although the difference was most evident in comparison with the combination of second arterial and late phases. CONCLUSION: An automated bolus-tracking program can be used to optimize the timing of hepatic arterial phase CT. Multiphasic CT performed using this technique is useful in detection of small hepatocellular carcinoma.     

CT features of nonfunctioning islet cell carcinoma

To determine the computed tomographic (CT) characteristics of nonfunctioning islet cell carcinoma of the pancreas, the CT scans of 27 patients with that disease were reviewed. The pancreatic tumor was identified as a mass in 26 patients (96%). Demonstrated masses were 3-24 cm in diameter. Eight of the tumors (31%) were larger than 10 cm. Six tumors (22%) contained calcification. Of the 25 tumors evaluated with contrast enhancement, 20 became partially or diffusely hyperdense relative to nearby normal pancreatic tissue. Hepatic metastases were identified in 15 patients (56%), regional lymphadenopathy in 10 (37%), atrophy of the gland proximal to the tumor in six (22%), dilatation of the biliary ducts in five (19%), and dilatation of the pancreatic duct in four (15%). The CT appearances of the nonfunctioning islet cell tumors were compared with those of 100 ordinary (ductal) pancreatic adenocarcinomas. Although the two types of tumors were sometimes indistinguishable, features found to be more characteristic of islet cell carcinoma included a pancreatic mass of unusually large size, calcification within the tumor, and contrast enhancement of either the primary tumor or hepatic metastases. Involvement of the celiac axis or proximal superior mesenteric artery was limited to ductal carcinoma.     

肾脏肿瘤的CT诊断

目的：分析肾脏良恶性肿瘤的ＣＴ表现，探讨ＣＴ对该类疾病的诊断价值。材料和方法：对手术和病理证实的１０４例肾脏肿瘤进行回顾性分析，所有病例均行平扫和增强。结果：１０４例中，良性肿瘤６例（占５．８％），均为肾血管平滑肌脂肪瘤（ＡＬＬ），ＣＴ表现为肾实质内含多种不同成分的混杂密度肿块，可有分房、分隔，内含脂肪是其特征性表现，增强后软组织部分强化，而脂肪区无强化。恶性肿瘤９８例（占９４．２％），其中肾细胞癌（ＲＣＣ）８２例，ＣＴ表现为肾实质内形态不规则、边界欠清的低密度软组织块影，动态增强后可见一过性强化。应用动态薄层增强ＣＴ扫描法准确检出小肾癌（最大径＜３ｃｍ）８例，该法为目前检查小肾癌的最佳影像方法。肾盂癌１１例（均为移行细胞癌），ＣＴ表现为肾盂内分叶状低密度软组织块影，增强后病灶强化不明显。肾母细胞瘤（Ｗｉｌｍｓ瘤）５例，均为４岁（平均２．５岁）以下小儿，ＣＴ表现为肾实质部位较大的不规则较低密度软组织块影，增强后无明显强化。结论：增强前后ＣＴ扫描对肾脏肿瘤的定位、定性诊断及术前分期均具有十分重要的价值。     

胰腺腺泡细胞癌的CT及MRI表现

目的 分析胰腺腺泡细胞癌（PACC）的CT及MRI影像表现旨在提高术前诊断水平。 方法 回顾性收集经病理确诊的11例PACC病人的CT（5例）或MRI（6例）影像资料,分析其特征性表现。 结果 实验室检查3例甲胎蛋白（AFP）升高,4例糖类抗原19-9（CA19-9）升高。CT和MRI影像上,11例均为单发,8例为实性,3例为囊实性;6例病灶位于胰头部,5例位于胰体尾;病灶平均最大径为（5.69±3.53） cm。增强扫描后,病灶多呈不均匀渐进式强化（CT 4例,MRI 5例）,少数表现为延迟期强化程度略减低（CT和MRI各1例）。10例病灶与正常胰腺组织进行了比较,动脉期强化程度均低于胰腺组织,延迟期强化程度可降低（CT 上3例,MRI 上1例）或升高（CT上 1例,MRI上 5例）。PACC病灶外常见包膜（8/11例）;病灶内多见囊变坏死（8/11例）,少数可见钙化（1/11例）。病灶可伴有胆管、胰管同时扩张,或仅见胰管扩张,也可伴胰腺实质萎缩;可侵犯肠系膜上动静脉、脾动静脉,少数可累及十二指肠、邻近胃壁及肾上腺。部分病人伴有淋巴结或远处转移。 结论 PACC的实验室检查及影像表现具有一定特征性,CT及MRI对该病的术前诊断具有一定价值。     

肉瘤样肾细胞癌的CT表现及手术病理所见

目的 :探讨肉瘤样肾细胞癌的CT表现与临床病理基础 ,提高对肉瘤样肾细胞癌的认识。方法 :对经手术病理证实的 6例肉瘤样肾细胞癌的CT和临床资料进行回顾性分析。结果 :所有病例均表现为肾实质性肿块 (右肾 4例 ,左肾 2例 )。平扫为分叶状、等密度或略高密度不均质实性肿块。有灶性坏死区 ,增强后不均匀轻度强化 ,与正常实质分界不清。全部病例侵犯肾周间隙达肾周筋膜。 4例侵犯肾静脉或 /和下腔静脉。 3例区域淋巴结转移。 2例远处转移。术后3月内复发 2例。半年内 4例因复发或 /和远处转移而死亡。结论 :肉瘤样肾细胞癌少见 ,多为分叶状、密度不均、边界不清肿块 ;极易侵犯周围组织、肾静脉或下腔静脉并出现淋巴结或远处转移 ;恶性度极高 ,愈后极差。CT是发现病灶、判断预后可靠和准确的方法之一。确诊依靠术前细针穿刺活检。