Pancreatic adenocarcinoma: signs of vascular invasion determined by multi-detector row CT

The purpose of this study was to analyse multi-detector row CT (MDCT) signs of peripancreatic arterial and venous invasion in pancreatic carcinoma. Among 101 patients with pancreatic carcinoma examined by MDCT, 54 candidates for surgery were pre-operatively evaluated for vascular invasion based on MDCT signs. The peripancreatic major vessels (including superior mesenteric artery, coeliac artery, common hepatic artery, superior mesenteric vein and portal vein) were examined carefully by surgeons during the operation. At surgical exploration, 78 of 224 vessels were invaded by tumour. The invaded peripancreatic major arteries (n = 29) and veins (n = 49) presented different MDCT signs: 43% of invaded veins (18/42, except for 7 occluded veins) were surrounded by tumour less than 50% of the vessel circumference compared with 97% (28/29) of the invaded arteries, which were surrounded by tumour more than 50% of the vessel circumference or were embedded in tumour (p<0.001). 69% (34/49) of the invaded veins had vascular stenosis or obliteration, compared with 41% (12/29) of the invaded arteries (p<0.05). Irregularity of the vein wall, 74% (31/42, except for 7 occluded veins); occurred more often than that of the artery wall, 45% (13/29) (p<0.05). In conclusion, the MDCT signs of peripancreatic arterial and venous invasion have different characteristics, which should be considered in pre-operative evaluation.     

Assessment of vascular invasion in pancreatic carcinoma by MDCT

Background

Pancreatic cancer is one of the aggressive cancers with poor resectability and survival rates. The relationship to adjacent vessels must be assessed before deciding the choice of treatment.

Aim

Assessment of the MDCT signs of arterial and venous invasion in pancreatic carcinoma.

Subjects and methods

Total of 179 of the major peripancreatic vessels (CA; CHA; SMA; PV; SMV) in 47 patients who underwent surgery for pancreatic cancer after MDCT were assessed at surgery and compared with CT findings. Statistical analysis of the findings was done using Chi square test.

Results

115 vessels were not invaded at surgery, while the remaining 64 vessels were invaded (22 arteries and 42 veins). There was over all statistically significant difference between arterial and venous invasion regarding stenosis, occlusion, infiltration and circumferential involvement of the vessel wall.

Conclusion

Assessment of vascular invasion is crucial in the evaluation of resectability for pancreatic cancer. MDCT is an accurate diagnostic tool for peripancreatic vascular invasion in cancer pancreas.     

胰腺癌侵犯胰周主要血管的CT表现分析

目 的分析多层螺旋CT(MSCT)胰腺检查，胰腺癌侵及胰周主要动、静脉的不同CT表现特征。方法 MSCT诊断胰腺癌68例患者中，33例行手术治疗(其中12例行胰十二指肠切除术，21例剖腹探查发现不可切除)，病理结果均证实为胰腺导管细胞癌。术中由手术者仔细探查胰周主要血管[肠系膜上动脉(SMA)、腹腔干(CA)、肝动脉(HA)、肠系膜上静脉(SMV)及门静脉主干(PV)]。结果 165支受检血管中，手术探查发现103支血管未受侵犯，其余62支血管受侵，MSCT术前检查，8．1％(5／62)受侵血管误判为未受侵犯(假阴性)。其余受侵的胰周主要动、静脉(57支)具有不同的CT表现特征：胰周主要动脉受侵时，均被肿瘤包绕大于管周的1／2或完全包埋于肿瘤中。胰周主要静脉受侵时，部分静脉血管被肿瘤包绕小于管周的1／2：SMV为4支(4／17)，PV为2支(2／13)，但同时均出现管壁受浸润或管腔狭窄或管腔形态改变；胰周静脉受侵犯时出现管腔狭窄或闭塞的机会较胰周动脉大：SMV为11支(11／17)，PV为12支(12／13)，而CA为3支(3／8)，HA为4支(4／7)，SMA为4支(4／12)；胰周静脉受侵犯时管壁呈浸润性改变的比例较胰周动脉高：SMV为11支(11／17)，PV为7支(7／13)，而CA为3支(3／8)，HA为2支(2／7)，SMA为6支(6／12)。结论 胰周动、静脉受侵及时，其CT表现具有不同特征。     

胰腺癌血管侵犯的不同CT诊断标准的研究

目的:研究胰腺癌血管侵犯的不同CT诊断标准的优劣。材料和方法:回顾性收集我院经多层螺旋CT三期动态增强扫描并经手术病理证实为胰腺导管细胞癌的36例患者。CT轴位图像结合CTA(以MIP和VR方法重建)以及多平面重建(MPR)分别对这些血管以Loyer和Lu血管分级CT标准进行分级,并和手术结果进行对照,分别作出受试者工作特性曲线(ROC),比较曲线下面积的差异。另外,运用Lu的CT诊断标准分别评价胰周动脉和静脉受侵的准确性、灵敏度、特异度、阳性预测值、阴性预测值、Youden指数,研究Lu的CT诊断标准对动静脉分级的差异。结果:Loyer和Lu的CT诊断标准所得的灵敏度、特异度分别为84.5%、86.0%、81.4%、91.8%,两个诊断标准的ROC曲线下面积分别为0.886、0.912,经统计学检验无明显差异。应用Lu的CT诊断标准,胰周动静脉受侵的阳性预测值分别为57.1%和71.0%。结论:分别以Loyer和Lu血管分级CT标准对胰腺癌胰周血管侵犯进行分级,两者的诊断价值相同,Lu的CT诊断标准的最佳诊断分界点应在90°-180°之间,此外,它对胰周动脉的价值要比静脉差。     

Teardrop superior mesenteric vein: CT sign for unresectable carcinoma of the pancreas

OBJECTIVE: Our objective was to investigate whether a tethered, teardrop-shaped superior mesenteric vein (SMV) is a reliable CT indicator of unresectable adenocarcinoma of the head of the pancreas. MATERIALS AND METHODS: CT scans of 92 patients with high suspicion for pancreatic head adenocarcinoma were retrospectively reviewed by two radiologists who were unfamiliar with the patients' outcomes. The reviewers were asked to assess whether the teardrop SMV sign was present or not; agreement was reached by consensus. Teardrop SMV was considered absent in patients with an obstructed vessel. RESULTS: Of 92 patients, 30 had a normal pancreas without a teardrop SMV. A mass in the head of the pancreas was seen in all 62 patients with cancer. Of these 62 patients, 30 (seven with teardrop SMV) were deemed to have inoperable disease by standard CT or clinical criteria. The remaining 32 patients underwent surgery; only 15 of these 32 had successful pancreatoduodenectomies. No patient with resectable tumor had an unequivocal teardrop SMV sign. In 17 patients (13 with teardrop SMV), resection of the tumor could not be accomplished because of vascular encasement (n = 12) or metastasis (n = 5). Added to conventional signs, teardrop SMV significantly increased CT's sensitivity (from 60% to 91%) and accuracy (from 79% to 95%) without significantly changing its specificity (from 100% to 98%) for resectability of pancreatic head cancer. CONCLUSION: The teardrop SMV is a reliable sign for predicting unresectability of adenocarcinoma of the head of the pancreas and can significantly contribute to preoperative planning.     

不同扫描方案的多层螺旋CT检查在胰腺癌术前评估中的价值

目的:通过对3组病例行不同扫描时相的多层螺旋CT检查,分析不同扫描方案的胰腺多期增强扫描在胰腺癌术前评估中的价值。方法:将临床因怀疑胰腺癌而申请MDCT检查的病例随机分为3组,行不同扫描时相的MDCT增强扫描。三组病例的扫描时相分别为:第1组(动脉期和门脉期),第2组(胰腺实质期和门脉期),第3组(动脉期、胰腺实质期和门脉期)。图像分析内容包括肿瘤位置、有无周围器官及主要血管的侵犯、有无器官转移、腹膜或腹腔转移等,最后评估肿瘤是否可以手术切除,并与手术结果对照。计算每组病例的阳性预测值、阴性预测值、敏感性、特异性及准确率,并将诊断结果进行统计检验。结果:三组病例对于胰腺癌术前可切除性评价的阳性预测值、阴性预测值、敏感度、特异度及准确率分别为第1组:93.5%、66.7%、87.9%、80%及86%;第2组:100%、80%、93.8%、100%及95.0%;第3组:100%、87.5%、97.1%、100%及97.6%。第1组诊断结果与第3组间差异有显著性意义。结论:胰腺实质期与门脉期应作为胰腺癌术前MDCT增强的最基本扫描时相,如果需要进一步观察胰周动脉走行及肿瘤的供血情况,可以加做动脉期扫描。以原始横断面图像为基础,结合MPR、MIP、VR、CPR等重建技术,MDCT对于胰腺癌的术前可切除性评价多能做出正确诊断。     

多层螺旋CT血管成像对胰腺癌侵犯胰周血管的表现及可切除性评价

目的：评价多层螺旋CT血管成像（MSCTA）检查对胰腺癌侵犯胰周主要血管的影像表现及手术可切除性评价。方法：使用16层螺旋CT对胰腺癌患者扫描后,进行动脉期和门脉期胰周主要血管CTA三维成像。以三维图像为主,结合原始图像对胰周血管是否受累进行判别及评价,并与手术对照。结果：51例手术病例与手术结果比较,术前MSCTA判断不能切除的21例中手术均无法切除,术前MSCTA判断能切除的30例中手术结果能切除28例,2例误判,判断符合率为93%。结论：MSCTA对于胰腺癌术前可切除性评估具有重要的临床意义。     

Assessment of vascular invasion in pancreatic head cancer with multislice spiral CT: value of multiplanar reconstructions

The use of multiplanar reconstructions (MPRs) generated from multislice spiral CT (MSCT) data sets in the preoperative assessment of vascular invasion in pancreatic cancer was evaluated. Forty patients underwent biphasic high-resolution MSCT prior to surgery for pancreatic head cancer. Image reconstruction included thin-slice axial, sagittal and coronal MPRs as well as an MPR perpendicular to the course of a major peripancreatic vessel in proximity to the tumor. CT criteria for vascular invasion were: (1) circumferential involvement >180° and (2) vessel narrowing. Imaging findings of 52 vessels were correlated with surgical and histopathological reports. Regarding the CT criterion circumferential involvement, vascular invasion was demonstrated on axial MPRs with a sensitivity and specificity of 58 and 97%. For the assessment with coronal and sagittal MPRs sensitivity was only 47%. Vascular invasion was recognized best on perpendicular MPRs with a sensitivity, specificity and accuracy of 74, 97 and 88%, respectively. Vessel narrowing was a less reliable CT criterion for vascular invasion, mainly due to the lower specificity of 91% obtained with each available MPR. Thin-slice MPRs oriented perpendicularly to a possibly invaded vessel exactly depict the grade of circumferential involvement and thus have the capability to improve the assessment of vascular invasion in pancreatic cancer.     

MDCT in Pancreatic adenocarcinoma: prediction of vascular invasion and resectability using a multiphasic technique with curved planar reformations

OBJECTIVE: The objective of our study was to determine the negative predictive value of MDCT with curved planar reformations for detecting vascular invasion and predicting overall resectability in patients with pancreatic adenocarcinoma. MATERIALS AND METHODS: Imaging findings related to vascular invasion and overall tumor resectability in 25 patients who underwent contrast-enhanced biphasic MDCT evaluation were correlated with actual vessel invasion and overall resectability determined at surgery and pathologic examination. The presence of vascular invasion was assessed in 110 major peripancreatic vessels in 22 patients who underwent resection. RESULTS: On MDCT, 23 (92%) of 25 patients were deemed to have resectable pancreatic adenocarcinoma. The tumors in the remaining two (8%) were considered not resectable because of the presence of vascular invasion (which was confirmed in only one patient at surgery). Of those 23 patients deemed to be candidates for curative resection on the basis of MDCT results, 20 were found to have resectable adenocarcinoma at time of surgery, yielding a negative predictive value for MDCT of 87% (20/23 patients) for overall resectability. In the other three patients, adenocarcinoma was deemed to be unresectable because of small metastases to the liver (two patients) or to the peritoneum (one patient) discovered at surgery. For detection of vascular invasion, MDCT yielded a negative predictive value of 100% (108/108 vessels) with no false-negative findings and an accuracy of 99% (109/110 vessels) with 108 true-negative findings, one true-positive finding, and one false-positive finding. CONCLUSION: Our preliminary data on MDCT show that the technique has excellent negative predictive value for vascular invasion and good negative predictive value for overall tumor resectability in patients with pancreatic adenocarcinoma, suggesting an improvement over previous results reported using single-detector CT. The problem of undetected micrometastases to the liver and peritoneum remains.     

Can MDCT or EUS features predict the histopathological grading scheme of pancreatic neuroendocrine neoplasms?

Purpose

To identify whether the features of preoperative MDCT or EUS could predict the histopathological grading scheme of pancreatic neuroendocrine neoplasms (pNENs).

Methods

A total of 25 patients with pNENs were enrolled in the present study. The qualitative and quantitative variables were reviewed. The qualitative variables included location, contour, border, necrosis, intratumoral vessel, homogeneity, calcification, peripancreatic fat/vessel infiltration, pancreatic duct dilatation, mass within pancreas, lymphadenopathy and hepatic metastasis on MDCT and border, echogenicity, cystic/solid and blood flow on EUS. The quantitative variables included long diameter (LD), short diameter (SD), unenhanced mass attenuation (UMA), unenhanced pancreatic attenuation (UPA), arterial phase mass attenuation (APMA), arterial phase pancreatic attenuation (APPA), portal venous phase mass attenuation (PVPMA), portal venous phase pancreatic attenuation (PVPPA), arterial phase enhancement degree (APED) and portal venous phase enhancement degree (PVPED). In addition, sex and age were also evaluated. Histopathological classifications met the criterion of 2010 edition WHO Histopathological Classifications. Kruskal–Wallis test and Boruta algorithm were conducted.

Results

Lymphadenopathy and peripancreatic fat or vascular invasion foretold higher histopathological grading level while well-defined border on EUS image lower grading level.

Conclusions

Lymphadenopathy, border on EUS image and peripancreatic fat or vascular invasion can predict the histopathological grading scheme of pNENs.

     

螺旋CT增强扫描在胰头癌诊断中的价值

目的 :探讨螺旋CT增强扫描在胰头癌诊断中的意义及其不同CT征象的诊断价值。方法 :搜集 45例经临床、内镜超声等诊断或经手术病理证实的胰头癌病例 ,回顾性分析其螺旋CT成像中各种特异性表现的诊断敏感性 ,总结其CT扫描技术要点。结果 :螺旋CT增强扫描显示胰头癌最常见的CT征象有相对低密度瘤灶 ( 10 0 % )、胰周血管受侵( 86.7% )、胰头、体尾部比例失调 ( >1.2 ,占 80 .0 % )、胆总管扩张伴下端截断征 ( 4 6.7% )、双管征 ( 3 3 .3 % )、淋巴及脏器转移 ( 2 0 .0 % )等 ,螺旋CT动脉期 ( 2 5～ 3 0s)、门静脉期 ( 5 0～ 65s)动态双期扫描的诊断价值最大。结论 :采用适时的螺旋CT增强扫描时间能更好显示胰头癌的CT特征 ;综合分析各种CT征象对诊断有很大价值。     

Preoperative assessment of vascular invasion in exocrine pancreatic cancer by multidetector CT

Purpose

To evaluate multidetector CT (MDCT) signs of vascular invasion in pancreatic carcinoma.

Patients and methods

Retrospective review of preoperative dynamic MDCT of 42 patients with pathologically proven pancreatic carcinoma.

Results

Surgically confirmed invaded vessels were 19 arteries and 33 veins. Multiple signs of vascular invasion were assessed.

Conclusion

Significant advances have been made in the ability of MDCT to visualize pancreatic cancer and to stage disease when close attention is paid to technique with special attention to multiple signs of vascular invasion.     

胰腺癌CT表现与手术病理及D2-40表达的相关性研究

目的:探讨胰腺癌CT征象与手术病理及癌组织淋巴管生成之间的关系.方法:对33例胰腺癌患者(男24例,女9例,年龄38～79岁)行CT平扫及动脉期、门静脉期、延迟期增强扫描,分析胰腺癌的病灶大小、密度、强化程度、对胰周组织的侵犯、胰胆管扩张,胰周淋巴结等CT征象,所有病例均行手术切除,术后标本采用单克隆抗体D2-40免疫组化方法检测肿瘤组织中的瘤周和瘤内淋巴管密度(pLVD,iLVD).使用Kappa检验和t检验统计学方法将CT表现与病理结果、淋巴管密度进行对照.结果:CT诊断胰腺癌病灶的大小、胰周组织侵犯、胰周淋巴结转移与手术病理结果一致性良好(P＜0.05),CT对胰腺癌分期的准确性为78.79％(26/33).CT征象中胰周组织侵犯、胰周淋巴结肿大、分期与胰腺癌pLVD有关(P＜0.05).与iLVD无关(P＞0.05);CT征象中病灶大小、密度、胰胆管扩张、病灶强化程度则与pLVD、iLVD均无关(P＞0.05).结论:CT能较可靠地反映胰腺癌的病理学特征;胰周组织侵犯、胰周淋巴结肿大等CT征象与胰腺癌组织的淋巴管密度有关,可一定程度上揭示胰腺癌组织的淋巴管生成、淋巴结转移及判断预后.     

胰腺无功能性内分泌肿瘤的螺旋CT诊断与鉴别诊断

目的:分析胰腺无功能性内分泌肿瘤螺旋CT多期扫描的表现,提高CT对无功能性胰腺内分泌肿瘤诊断的正确性。材料和方法:回顾性分析25例经穿刺及手术病理证实的胰腺无功能性内分泌肿瘤的薄层螺旋CT多期扫描资料。螺旋CT采用常规平扫和薄层三期动态增强扫描即动脉期、门脉期和延迟期,三期扫描延迟时间分别为25s,70s和120s。结果:25例患者共检出26个病灶,位于胰头部10个病灶,胰颈部5个病灶,胰体部3个病灶,体尾部4个病灶,胰尾部4个病灶,其中1例同时有两个病灶分别位于胰头和体尾部。肿瘤平均大小为4.0cm。14个病灶呈等密度;12个病灶呈略低密度,密度不均匀,其中可见更低密度灶;其中5个病灶内可见钙化。增强扫描动脉期共18个病灶明显强化,其中6个病灶均匀强化,12个病灶不均匀强化,6病灶呈中等程度强化,2个病灶动脉期轻度强化。3例肿瘤位于胰头者,2例出现了胆道和胰管扩张,胰体尾部萎缩,另1例仅出现胰管轻度扩张,1例肿瘤位于体部者出现远端胰管扩张伴实质萎缩。25例患者8例出现多发肝富血供转移灶,其中1例患者同时出现肺和脊柱的多发转移,无胰周及后腹膜淋巴结转移;3例出现肿瘤邻近血管的侵犯,其余为邻近血管推移受压改变。结论:无功能性胰腺内分泌肿瘤多较大,富血供,常见钙化,较少出现周围血管及胰胆管直接侵犯,较少出现后腹膜淋巴结转移及神经丛侵犯,根据有无肝脏及其他脏器转移、淋巴结转移及周围血管侵犯,进一步提示肿瘤的良恶性。     

Blunt pancreatic trauma: evaluation with MDCT technology

The purpose of this paper is to determine the relative frequency of multi-detector CT (MDCT) findings of pancreatic injury in blunt trauma and to determine their diagnostic accuracy in predicting main pancreatic duct injury. Fifty-three patients (31 male, 22 female; mean 44.1 years) with blunt trauma and admission MDCT findings suspicious for pancreatic injury or who underwent MDCT and had a discharge diagnosis of pancreatic trauma were included in this study. Two radiologists reviewed all images and recorded findings suspicious for pancreatic injury, which were subsequently compared to surgical findings to generate diagnostic accuracy. MDCT imaging findings suggestive of pancreatic injury included low attenuation peripancreatic fluid (n?=?51), hyperattenuating peripancreatic fluid (n?=?13), pancreatic contusion (n?=?7), active hemorrhage (n?=?2), and pancreatic laceration (n?=?16). Diagnostic accuracy of the various imaging findings varied for diagnosing main duct injury; there were highly sensitive, nonspecific imaging findings such as the presence of low attenuation peripancreatic fluid (sensitivity, 100 %; specificity 4.9 %) as well as insensitive, specific findings such as visualizing a pancreatic laceration involving >50 % of the parenchymal width (sensitivity, 50 %; specificity, 95.1 %). In the setting of blunt abdominal trauma, MDCT imaging findings can be grouped into two categories for determining integrity of the main pancreatic duct: indirect, highly sensitive but nonspecific findings and direct, specific but insensitive findings. Awareness of the clinical implications of the various MDCT imaging findings of pancreatic trauma is useful in interpreting their significance.     

多层螺旋CT胰腺增强扫描：扫描方案的选择及对胰周血管的评价

目的：通过胰腺同层动态增强扫描,获得感兴趣区的时间-密度曲线,确定胰腺增强扫描的最佳延迟时间,并应用此扫描方案分析胰周血管的显示率。方法：①随机选择20例无胰腺疾病的患者进行胰腺同层动态增强扫描,获得感兴趣区的强化峰值及到达峰值时间;②随机选择40例无胰腺疾病的患者进行胰腺三期增强扫描,分析胰周血管的显示率。结果：①腹主动脉强化峰值时间约为30s,平均强化峰值为350．3HU,20s时平均CT值为316．7HU;门静脉强化峰值时间约为45s,胰腺实质强化峰值时间约为40s,肝脏实质强化峰值时间约为55s,曲线到达峰值后75s内处于平台期;②胰周主要动脉（CA、HA、SA、sMA）的显示率为100％（40／40）,除AIPDA以外的其它胰周小动脉显示率为75％～100％。胰周主要静脉（PV、SV、SMV）的显示率为100％（40／40）,除AIPDV以外的其它胰周小静脉显示率为75％-100％。结论：在注射剂量100ml,注射流率4ml／S时,建议多层螺旋CT胰腺增强扫描的延迟时间分别为动脉期20s,胰腺实质期45s,门静脉期或肝脏期70s。     

Acute pancreatitis: value of CT as a predictor of outcome

A prospective study was performed on the relationship of CT findings to the clinical course of 148 patients with acute pancreatitis. The type of pancreatic inflammation seen on CT was classified into six categories based on an overall assessment of size, contour and density of the gland, and peripancreatic abnormalities. The majority (94%) of patients in whom CT showed mild pancreatic changes (grades A, B and C) had two or less positive clinical indicaters of severe pancreatitis (Ranson's signs). In contrast, 92% of patients in whom CT showed more severe changes of pancreatitis (grades D, E or F) had three or more positive signs. The nine patients who died with pancreatitis-related complications were in grades D, E or F. We wish to draw attention to a CT appearance which we have called 'fat islets' (low density intrapancreatic or peripancreatic areas, the contents of which approach fat in attenuation values); there was a strong correlation between this appearance and subsequent infection.     

螺旋CT双期扫描对胰腺癌可切除性的评价

目的 评价螺旋ＣＴ双期扫描对胰腺癌可切除性的价值。材料与方法 对４２例拟诊胰腺癌随后又行手术治疗的患者作出前瞻性的诊断和可切除性的评估。病理结果：胰腺癌３３例,非胰腺癌９例。ＣＴ双期延迟扫描时间分别为２５ｓ和６０ｓ。并将ＣＴ判断的结果与手术结果作对比。结果 ４２例中,螺旋ＣＴ正确诊断３９例（９３％）。螺旋ＣＴ判断可切除性的敏感性为８９％,牧场划性为９２％,准确性为９１％。１０例肝转移癌,ＣＴ诊断８     

Vascular encasement by pancreatic cancer: correlation of CT findings with surgical and pathologic results

PURPOSE: The purpose of this study was to correlate thin-slice high-resolution helical CT findings of arterial and venous involvement in pancreatic cancers with surgical and histopathologic results. METHOD: Forty-eight patients with pancreatic cancer underwent preoperative thin-slice high-resolution helical CT, followed by surgical dissection of the pancreatic vessels during curative or palliative surgery. Major vessels running within 1 cm from the tumor margin were evaluated. CT appearance was graded on a 0-4 scale (0: none, 1: <24%, 2: 25-49%, 3: 50-74%, 4: 75-100%) by circumferential contiguity of tumor to vessels. Resected specimens were available from 26 patients. RESULTS: Surgical correlation of CT findings was available in 89 veins and 83 arteries, and both surgical and histologic correlation was available for 42 veins and 29 arteries. At surgical observation, 29 of 35 veins (82.9%) evaluated as CT grade 3 or 4 were found to be involved, whereas only 18 of 30 arteries (60%) evaluated as CT grade 3 or 4 were proved to be involved. On microscopic observation, tumor invasion to the portal venous systems was confirmed in 15 of 42 (35.7%) vessels, and this invasion was depicted as from CT grades 1 to 4. In arteries, tumor invasion was seen in 3 of 29 vessels (10.3%), all of which were graded as 3 or 4 by CT. CONCLUSION: The grading system of vascular invasion should differ between arteries and veins. Involvement of the venous system exceeding one-half circumference of the vessels (grade 3 or 4) was suggestive of vascular invasion; however, this criterion was not always satisfactory for the evaluation of tumor invasion in the arterial system.     

Prevalence of the Polar Vessel Sign in Parathyroid Adenomas on the Arterial Phase of 4D CT

BACKGROUND AND PURPOSE:The “polar vessel” sign has been previously described on sonography of parathyroid adenomas. We estimated the 4D CT prevalence of the polar vessel sign and determined features of parathyroid adenomas that are associated with this sign.MATERIALS AND METHODS:Twenty-eight consecutive patients with parathyroid adenomas underwent 4D CT between 2008 and 2012 at 2 institutions. 4D CT images were reviewed for the presence of the polar vessel sign and a second vascular finding of an enlarged ipsilateral inferior thyroid artery. The polar vessel sign was correlated with adenoma weight and size and arterial phase CT attenuation.RESULTS:Thirty-two parathyroid adenomas in 28 patients were studied, with a mean adenoma weight of 0.66 ± 0.65 g, a mean maximal CT diameter of 11.1 ± 4.9 mm, and a mean arterial attenuation of 148 ± 47 HU. The polar vessel sign was seen in 20/32 (63%) adenomas. Adenomas with a polar vessel had higher arterial phase attenuation than adenomas without a polar vessel (163 and 122 HU, respectively, P < .01). Size and weight were not significantly different for adenomas with and without polar vessels. An enlarged inferior thyroid artery was seen in only 2/28 (7%) patients with unilateral disease.CONCLUSIONS:The polar vessel sign was present in nearly two-thirds of parathyroid adenomas on 4D CT and was more likely to be present in adenomas that had greater arterial phase enhancement. This sign can be used along with enhancement characteristics to increase the radiologist''s confidence that a visualized lesion is a parathyroid adenoma rather than a thyroid nodule or lymph node.

4D parathyroid CT is increasingly used for preoperative localization of parathyroid adenomas. 4D CT was first described in 2006 and involves ≥2 contrast phases with high-resolution multiplanar images of the neck and upper chest.¹ The characteristic features of parathyroid adenomas on 4D CT are low attenuation on noncontrast imaging, peak enhancement on the arterial phase, and washout of contrast on the venous phase.^2–4 These allow differentiation between a parathyroid adenoma and its mimics, such as thyroid nodules and lymph nodes.Characteristic enhancement may not be evident in all cases due to adenoma composition, small adenoma size, or suboptimal arterial timing. In these cases, the radiologist must rely on his or her knowledge of the expected locations of adenomas and morphologic findings. A morphologic feature that has been previously described on sonography is a feeding artery (usually a branch of the inferior thyroid artery) to the adenoma.^5,6 Small arteries cannot be seen on nuclear scintigraphy or MR imaging because of lower spatial resolution, and they have not been described on single venous phase CT, to our knowledge. In a recent review article, the authors noted the presence of a “polar vessel” sign on the arterial phase of 4D CT.⁴ The polar vessel sign can represent either an enlarged feeding artery or a draining vein seen on the arterial phase of imaging, and it is characterized by a vessel that terminates in a parathyroid adenoma and that is larger than contralateral neck vessels in a similar location.The purpose of this study was to estimate the prevalence of the polar vessel sign on 4D CT and to determine features of parathyroid adenomas that are associated with this sign. We hypothesize that a polar vessel may be more commonly seen in adenomas that are larger or have more vivid arterial enhancement.