CT of acute pancreatitis: correlation between lack of contrast enhancement and pancreatic necrosis

This study was performed to determine if a correlation exists between pancreatic parenchymal enhancement or lack thereof on contrast-enhanced CT and surgical evidence of pancreatic necrosis. Accurate CT assessment of pancreatic vascular perfusion would be helpful in preoperative planning before pancreatic debridement and necrosectomy. The CT scans and medical records were blindly and retrospectively reviewed in 13 patients with the operative diagnosis of pancreatic necrosis. In all cases, CT examinations preceded surgery within 72 hr. Surgical and pathologic findings served as the gold standards for the diagnosis of pancreatic necrosis. Seven (54%) of 13 patients had a region or regions of parenchymal necrosis within the head, body, and/or tail of the pancreas seen during surgery. All seven of these patients had no pancreatic enhancement on CT in at least one region of the pancreas (CT sensitivity = 100%). In four of the seven, two regions were found to be necrotic at surgery, but only one of the two segments did not enhance on CT scans. In three of the seven patients, lack of contrast enhancement on CT (no enhancement of the pancreatic head and body in two patients and throughout the gland in another) correlated with necrosis in the same regions at surgery. The remaining six (46%) patients, who had peripancreatic or small, focal, and/or superficial areas of pancreatic necrosis at surgery, had normal pancreatic enhancement on CT. Our results show that regions of pancreatic necrosis found surgically correlate with lack of enhancement of pancreatic parenchyma on CT. Peripancreatic necrosis and minor areas of focal or superficial parenchymal necrosis were not detected on CT.     

Primary central nervous system lymphoma: CT and pathologic correlation

CT findings of 15 patients with histologically proven primary central nervous system (CNS) lymphoma were reviewed with pathologic correlation in order to evaluate variable CT patterns. There were a total of 32 lesions. Of the 15 patients studied, seven had acquired immunodeficiency syndrome (AIDS), all diagnosed within the past 3 years. The CT observations of eight non-AIDS patients were consistent with findings reported previously. Most of the lymphomatous lesions were either hyper- or isodense, round or oval masses with homogeneous contrast enhancement and variable surrounding edema. Pathologic examination showed tightly packed preserved lymphoma cells without necrosis. In AIDS patients, rim or ring enhancement of lymphoma, indistinguishable from brain abscess, was frequently seen. Histologic examination consistently showed extensive tumor necrosis with preservation of viable tumor cells at the periphery. A third and infrequent CT pattern was multiple infiltrative nonnodular solid enhancement with extensive edema. Pathologic correlation showed infiltrating viable tumor cells without necrosis. The rim- or ring-enhancing brain lesion seen in AIDS patients can either be an abscess or a primary lymphoma; proper tissue collection is essential for correct diagnosis and appropriate treatment.     

Do acute lesions of Wernicke's encephalopathy show contrast enhancement? Report of three cases and review of the literature

Contrast medium was given intravenously to three nonalcoholic patients who underwent MRI or CT in the acute stage of Wernicke's encephalopathy. Pathological enhancement was not seen in one patient examined within 4 days of clinical onset, was mild in a another 3 days after clinical deterioration and marked in a patient examined 12 days after admission. Contrast enhancement of lesions was present in half of 12 cases of acute disease reported previously. There was a substantial overlap in the time interval between clinical onset and contrast-enhanced CT or MRI in the groups of enhancing and nonenhancing lesions. Since contrast enhancement may be absent in acute WE, proton-density and T 2-weighted images are more useful for diagnosis of this reversible but potentially fatal condition. Received: 18 December 1997 Accepted: 15 July 1998     

Selective intraarterial contrast-enhanced CT of pancreaticoduodenal tumors: early clinical experience in evaluating blood supply and detectability

OBJECTIVE: The purpose of this study was to compare CT with selective intraarterial contrast enhancement with IV contrast-enhanced CT for diagnostic usefulness in the detection of tumors in the pancreaticoduodenal region. SUBJECTS AND METHODS: intraarterial contrast enhanced CT was performed in 36 patients with tumors of the pancreaticoduodenal region. Feeding arteries of the tumors and distribution of hyperattenuating areas on intraarterial contrast-enhanced CT were analyzed with various routes of contrast material injections. The intraarterial contrast-enhanced CT scans were compared with the IV contrast-enhanced CT scans. RESULTS: In all 29 patients with standard vascular anatomy, the right cephalic portion of the pancreatic head was enhanced on CT during common hepatic or gastroduodenal arteriography and the left caudal portion was enhanced on CT during superior mesenteric arteriography. The enhanced areas were complementary to each other in the whole pancreatic head, including the tumor. Tumor conspicuity from the surrounding pancreatic tissue on intraarterial contrast-enhanced CT was not superior to that on IV contrast-enhanced CT in all but four patients with cystic tumors. After intraarterial contrast-enhanced CT, three patients with tumors less invasive than pancreatic ductal carcinoma underwent local resection of their lesions. CONCLUSION: Intraarterial contrast-enhanced CT for pancreaticoduodenal tumors has potential technical problems and is not valuable in improving the detectability of tumors other than cystic lesions because the enhancement of the wall and septa of the tumor is emphasized. However, the feeding artery of the tumor and its surrounding tissue were clearly depicted.     

Morphologic and functional changes in nontumorous liver tissue after radiofrequency ablation in an in vivo model: comparison of 18F-FDG PET/CT, MRI, ultrasound, and CT.

Rimlike contrast enhancement on morphologic imaging and increased tracer uptake on (18)F-FDG PET in the periphery of the necrosis can hamper differentiation of residual tumor from regenerative tissue after radiofrequency ablation of liver lesions. This study used MRI, CT, ultrasound, and (18)F-FDG PET/CT to assess the typical appearance of lesions in nontumorous animal liver tissue after radiofrequency ablation. METHODS: Lesions were created by radiofrequency ablation of normal liver parenchyma in 21 minipigs. Follow-up was performed by 3 contrast-enhanced morphologic modalities-MRI, CT, and ultrasound-and by (18)F-FDG PET/CT immediately, 3 and 10 d, and 1, 2, 3, and 6 mo after radiofrequency ablation. Images were evaluated qualitatively for areas of increased enhancement and regions of elevated tracer uptake. Furthermore, all images were assessed quantitatively by determination of ratios comparing enhancement/tracer uptake in the periphery of the necrosis with enhancement/tracer uptake in normal liver parenchyma. Imaging findings were compared with histopathology findings. RESULTS: Immediately after radiofrequency ablation, no increase in (18)F-FDG uptake was visible, whereas elevated enhancement was noticed in the periphery of the necrosis on all morphologic imaging procedures. At further follow-up, an area of rimlike increase in (18)F-FDG uptake surrounding the necrosis was detected on PET/CT. The rimlike pattern of increased enhancement in the arterial phase was present for all liver lesions on CT, MRI, and ultrasound, especially between day 3 and month 1 after the radiofrequency ablation. Both elevated glucose metabolism and enhancement persisted for 6 mo postinterventionally. Histologic examination showed a hemorrhagic border converting into a regeneration capsule. CONCLUSION: If performed immediately after radiofrequency ablation, (18)F-FDG PET/CT probably has benefits over those of morphologic imaging procedures when assessing liver tissue for residual tumor. Later follow-up may be hampered by visualization of peripheral hyperperfusion and tissue regeneration. Further studies on a patient population are essential.     

CT evaluation of pancreatic cancer. Analysis of resected tumours

Preoperative CT examination including dynamic scan was performed in 25 patients with pancreatic carcinoma. Dynamic scans, which clearly demonstrated the attenuation difference between the normal and neoplastic pancreatic tissue in 92% of cases, were superior to high dose contrast enhancement scans that failed to display the relatively hypodense component of tumours in 40%. Detailed comparison of CT interpretation and surgical or pathological findings revealed the usefulness of CT examination in the evaluation of tumour size and local invasion. However, low sensitivity in detection of metastatic lesions (range: 20-38%) indicates limitations of CT diagnosis.     

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。     

Using contrast-enhanced sonography to assess the effectiveness of transcatheter arterial embolization for hepatocellular carcinoma

OBJECTIVE: We evaluated the usefulness of contrast-enhanced wideband harmonic gray-scale sonography in assessing the therapeutic effects of transcatheter arterial embolization for patients with hepatocellular carcinoma and compared the findings of this imaging modality with those of helical CT. SUBJECTS AND METHODS: Twenty-nine patients with 39 hepatocellular carcinoma lesions were examined. We scanned lesions before and after therapy using contrast-enhanced wideband harmonic gray-scale sonography after injection of a galactose-palmitic acid contrast agent. All patients held their breath for 20--50 sec after injection while the vascularity of the tumor was observed. We then monitored tumor enhancement between 60 and 180 sec after injection with patients breath-holding for a few seconds. Lesions were considered to exhibit viable tumor residue if hypervascular enhancement was observed in the tumor. We compared this enhancement with helical CT findings. RESULTS: After therapy, 36 of the 39 lesions showed viable tumor residue on contrast-enhanced wideband harmonic gray-scale sonography, with no artifacts from iodized oil. Helical CT revealed a high-attenuation area in 12 of the 36 lesions, whereas 24 of the 36 lesions could not be evaluated for tumor residue as a result of artifacts from iodized oil accumulation in the tumor. The remaining three lesions showed complete deposition of iodized oil and complete necrosis on contrast-enhanced wideband harmonic gray-scale sonography. CONCLUSION: Contrast-enhanced wideband harmonic gray-scale sonography is useful in evaluating the therapeutic effects of transcatheter arterial embolization for hepatocellular carcinoma.     

Imaging of incidental cystic lesions of the pancreas

Cystic lesions of the pancreas, with an estimated prevalence of 20%, frequently are incidental findings at imaging on asymptomatic patients. Pseudocysts, typically in a setting of pancreatitis, should first be excluded. Characterization of cystic tumors is more complicated. Still, it is important to differentiate between benign and malignant lesions. Multi-detector row CT and MRI allow characterization of such lesions in over 75% of cases. Indeterminate lesions should undergo endoscopic US with biopsy/aspiration and fluid analysis, especially for mucin producing tumors (rounded with thick enhancing wall). When imaging fails to fully characterize a lesion, follow-up may be proposed for lesions less than 3 cm in size, that are either unilocular with thin nonenhancing wall (simple cyst) or lobulated multilocular with thin nonenhancing wall (serous cystadenoma, isolated side branch IPMTP). Follow-up imaging shows that these tumors usually show very little change over time. Management is based on comparing estimated patient survival without treatment to surgical risks (morbidity, mortality, functional sequelae from the procedure).     

Computed tomographic findings in cerebral toxoplasmosis in adults

The clinical and computerized tomographic (CT) findings in 10 patients with cerebral toxoplasmosis are reviewed. All patients with cerebral toxoplasmosis were homosexuals and/or intravenous drug users, and all patients had other manifestations of AIDS. Two presented with focal seizures, 4 presented with focal neurological deficit which progressively worsened, and 4 had evidence of diffuse neurological dysfunction (altered consciousness, generalized seizures). CT showed a single lesion in 3 patients and multiple lesions in 7 patients. Two patients had hypodense nonenhancing lesions(s). Eight patients had hypodense lesions with peripheral or nodular enhancement. The lesions were more commonly located in the cerebral hemispheres and subcortical gray matter nuclear masses (thalamus, basal ganglia). The finding of a hypodense lesion with a central slightly hyperdense noncalcified region that showed dense nodular homogeneous enhancement was quite characteristic of cerebral toxoplasmosis, but this pattern may also be seen in other neurological conditions including brain lymphomas.     

超声造影对氩氦刀治疗肝癌近期临床疗效的评价

目的 了解超声造影对氩氦刀治疗肝癌近期临床疗效评价的应用价值.方法 选取23例共26个肝癌病灶为观察对象.采用第二代新型对比剂SonoVue以及CPS(Contrast Pluse Sequencing)造影软件.全部病灶氩氦刀治疗后1周至3个月采用超声造影,评价治疗效果,并与常规超声和增强CT或MRI检查结果进行比较.结果 氩氦刀治疗后超声造影显示20个治疗区各期均无异常增强,判断肿瘤完全灭活;5个病灶局部有早期增强,提示有肿瘤残存;1枚可疑残存肿瘤.超声造影显示11枚新生病灶,较常规超声增加8枚,其中肿瘤直径≤1 cm的微小病灶6枚.1例微小复发灶超声造影未能显示,以最终诊断为金标准.超声造影诊断准确率为96.1%,与增强CT或MRI检查结果相同.结论 超声造影可较准确地判断氩氦刀治疗后肿瘤灭活程度,是评价氩氦刀疗效的一种有效方法,并有助于发现微小新病灶.     

软组织恶性纤维组织细胞瘤的临床影像学诊断

目的:回顾性分析26例恶性纤维组织细胞瘤(MFH)的临床影像学表现,讨论其影像学诊断。方法:搜集经手术病理及免疫组化证实的MFH 26例,男15例,女11例,40岁21例,占80.77%。病史3个月~5年。7例摄有X线平片。CT平扫17例,增强扫描8例。MR平扫15例,增强扫描8例。病灶大多位于大腿、小腿、前臂和臀部。23例位于深部软组织,3例位于表浅软组织。结果:21例(80.77%)呈不规则长圆形或长条形软组织肿块,直径5cm。3例X线平片表现为软组织肿块伴邻近骨质侵蚀性破坏,2例伴有骨膜增生。CT平扫多呈等、低或略低密度,仅1例高密度。CT增强均表现为明显不均匀强化,病灶边界均不清,累及邻近肌肉。CT上2个病灶内可见弧形钙化,其病灶直径均5.0cm。13例可见邻近骨骼破坏或骨膜增生。MR平扫15例,T1WI多呈等或低信号,合并出血4例。T2WI多呈高信号或混杂信号,10例病灶周围可见片状水肿信号。MR增强扫描8例,均呈明显不均匀强化,2例边界清楚,邻近肌肉受压推移,12例边界不清,邻近肌肉侵犯。6例可见邻近骨骼受侵。结论:发生于中老年人,位于下肢、前臂深部软组织的巨大肿块,尤其是呈长圆形分叶状或不规则长条状软组织肿块,边界不清,伴有邻近骨质破坏或骨膜反应,增强扫描呈明显不均匀强化者,应首先考虑恶性纤维组织细胞瘤。     

胰腺腺泡细胞癌的CT和MRI表现

目的：分析胰腺腺泡细胞癌（ACC）的CT和MRI表现,提高对该病的认识。方法：回顾性分析经手术病理或穿刺活检证实的5例ACc患者的CT和MRI表现。5例均行CT平扫及增强扫描,2例行MRI检查。实验室检查甲胎蛋白（AFP）升高2例。结果：5例ACC中,4例单发,1例多发。2例位于胰头钩突部,2例位于胰尾部,1例多发肿瘤位于胰头及胰尾部。肿瘤平均最大径4．0cm。2例形态不规则,2例呈卵圆形,1例可见浅分叶。1例肿瘤可见完整包膜。4例肿瘤以实性成分为主,1例呈囊实性（中央囊性伴出血坏死）。1例伴钙化。5例肿瘤CT平扫均呈不均匀低密度,动脉期呈轻度不均匀强化,门脉期强化程度较动脉期略增高,但低于周围正常胰腺。2例MRI扫描示病灶在压脂T1WI上为均匀低信号,压脂T2WI上为不均匀略高信号。3例伴胰管扩张,其中1例伴低位胆管梗阻。结论：ACC可有完整包膜,可伴出血坏死和钙化,增强呈渐进性强化,较少引起胰胆管阻塞,实验室检查可提示AFP升高。     

Assessment of liver tissue after radiofrequency ablation: findings with different imaging procedures.

Our goal was to assess the typical appearance of normal liver tissue immediately after radiofrequency ablation (RF-ablation) when imaged with contrast-enhanced ultrasound, CT, MRI, 18F-FDG PET, and PET/CT. METHODS: Nineteen RF-ablation sessions were performed on nontumorous liver tissue of 10 G?ttingen Mini Pigs. CT, ultrasound, MRI, 18F-FDG PET, and PET/CT were performed immediately after the intervention. All imaging procedures were evaluated qualitatively for areas of increased contrast enhancement (morphologic imaging) and regions of elevated tracer uptake (functional imaging). Images were assessed quantitatively by determination of ratios (r(p/p)) comparing contrast enhancement/tracer uptake in the periphery of the necrosis with contrast enhancement/tracer uptake of normal liver parenchyma. RESULTS: On morphologic imaging, an increase in contrast enhancement surrounding the ablative necrosis was detected in all lesions. Quantification of this area of increased contrast enhancement revealed ratios of r(p/p) = 1.57 +/- 0.2 for CT and r(p/p) = 1.57 +/- 0.19 for MRI. On PET and PET/CT, homogeneous tracer utilization was found surrounding all lesions. There were no areas of a focal or rim-like increase in glucose metabolism. The ratio r(p/p) was found to be 1.05 +/- 0.08 for functional data. Histologic examination revealed pooling of blood in the sinusoids of the lesion's periphery that was caused by outflow obstruction due to the central necrosis. CONCLUSION: On morphologic imaging, a rim-like increase of contrast enhancement was found immediately after RF-ablation resembling peripheral hyperperfusion. This area of contrast enhancement may hamper detection of residual tumor. On the basis of homogeneous tracer distribution surrounding the area of necrosis, PET and PET/CT may serve for early assessment of patients after RF-ablation.     

Hepatocellular carcinoma treated with percutaneous radio-frequency ablation: evaluation with follow-up multiphase helical CT.

PURPOSE: To determine serial changes in hepatocellular carcinomas (HCCs) treated with percutaneous radio-frequency (RF) ablation at long-term follow-up multiphase helical computed tomography (CT). MATERIALS AND METHODS: There were 43 nodular HCCs in 40 patients at follow-up CT performed not less than 12 months after RF ablation. All patients underwent follow-up multiphase helical CT immediately, 1 month, and then every 3 months after percutaneous RF ablation. The serial changes in attenuation, enhancement pattern, shape, other findings, and volume of the ablated lesions were analyzed at follow-up CT. RESULTS: Thirty-eight (88%) of 43 ablated lesions were of low attenuation, with absence of contrast material enhancement at immediate and 1-month follow-up CT, which is suggestive of successful treatment. The remaining five lesions (12%) showed peripheral nodular enhancement, suggesting residual viable tumor. Compared with volume changes at immediate follow-up CT, the mean percentages of volume change at 1, 4, 10, 16, and 19 months were 79%, 50%, 27%, 11%, and 6%, respectively. Of 43 ablated lesions, 24 (56%) were mostly round at immediate CT and remained unchanged at subsequent follow-up CT. Peripheral rim enhancement was seen in 34 (79%) of 43 lesions at immediate CT but resolved in all 34 lesions at 1-month follow-up CT. Other associated findings included iatrogenic arteriovenous shunt in 10 patients, perihepatic hemorrhage in three, and pneumothorax in one. CONCLUSION: Follow-up multiphase helical CT of HCCs treated with percutaneous RF ablation showed variable findings in the treated lesions and surrounding liver parenchyma.     

Interobserver variability in determining enhancement of renal masses on helical CT

OBJECTIVE: Because enhancing renal masses are often surgically excised, we assessed interobserver variability in determining enhancement of renal masses. SUBJECTS AND METHODS: Forty-nine complicated cysts or solid lesions were imaged with helical CT. Simple cysts (n = 20) were included, for a total of 69 lesions. Three radiologists obtained three region-of-interest measurements for each lesion in the unenhanced and nephrographic phases. Enhancement was defined as an attenuation increase of 15 H or more, provided that partial volume effects were not the cause. Observer concordance was defined as agreement among all three observers on whether a lesion was enhancing or nonenhancing. Measurement-interpretation agreement was defined as an observer's measuring an attenuation increase of less than 15 H and interpreting the lesion as nonenhancing or measuring an increase of 15 H or greater and interpreting the lesion as enhancing. RESULTS: For the 20 simple cysts, observer concordance was 100% and measurement-interpretation agreement was 100%. For the 49 complicated lesions, observer concordance was 90% and measurement-interpretation agreement was 84% (41/49). Of the five discordant lesions, three were 1.1 or 1.0 cm in size and were interpreted as being of high attenuation on the unenhanced scans, with enhancement, versus a high-attenuation mass with increasing attenuation attributed to volume averaging. The remaining two discordant observations were due to differing interpretations of normally enhancing renal parenchyma versus cyst wall or tumor nodularity. CONCLUSION: For most renal lesions, the observers agreed on whether enhancement was present or absent. Observers were prone to disagree about enhancement for small lesions (1.0-1.5 cm). Occasional disagreements on classification of larger lesions were due to differing interpretations of enhancing normal parenchyma versus abnormal tissue. Discrepancies between an observer's opinion on enhancement and the results of region-of-interest measurements suggest the possibility of disagreement among multiple observers.     

18F-FDG PET/CT对下肢开放骨折术后感染的定位诊断价值及引导作用

 目的 评价¹⁸F-FDG PET/CT对下肢开放骨折术后感染的定位诊断价值及对清创术的引导作用。方法 收集医院2018-07至2019-06收治的15例下肢外伤骨折术后可疑慢性局部感染患者资料,清创术前1周内接受¹⁸F-FDG PET/CT检查;根据PET/CT影像定位感染灶,并与术后病理、微生物培养结果及PET/CT对照;分别计算骨感染灶和软组织感染灶的平均SUV_max,并与1例SPECT/CT骨显像进行对比分析;评价PET/CT引导下清创术的效果。结果 15例中6例为单纯骨感染灶,3例为单纯软组织感染灶,6例同时存在骨感染灶及软组织感染灶;PET/CT共发现骨感染灶18处,软组织感染灶12处,其中骨感染灶SUV_max为5.1±3.4,软组织感染灶SUV_max为3.6±2.4;PET/CT对骨感染灶的诊断灵敏性为94.4%,对软组织感染灶的诊断灵敏性为83.3%;PET/CT诊断灵敏性高于SPECT/CT骨显像;经PET/CT引导下的一次清创治愈率为93.3%(14/15)。结论 ¹⁸F-FDG PET/CT诊断下肢开放骨折术后感染的准确性高,引导手术清创效果可靠。     

Hepatic leiomyosarcomas: CT features with pathologic correlation

The purpose of this study was to determine the computed tomographic (CT) features of hepatic leiomyosarcoma and to correlate them with pathologic findings. CT examinations of 15 patients with pathologically proven leiomyosarcoma of the liver were retrospectively reviewed. Three patients had primary leiomyosarcoma of the liver and 12 patients had 43 distinct hepatic metastases originating from a primary gastrointestinal (n = 8), uterine (n = 2) or retroperitoneal (n = 2) leiomyosarcoma. In the 11 patients who had partial hepatic resection or surgical biopsy of their tumors, a correlation was made between CT imaging and pathologic findings. Primary leiomyosarcomas showed heterogeneous enhancement; two displayed internal and peripheral enhancement, and one showed peripheral enhancement with a pseudocystic pattern (i.e. enhancing thick wall with internal nonenhancing low attenuation area). Leiomyosarcomas metastatic to the liver were homogeneous, showing no or moderate enhancement (10 of 43 metastases, 23%) or heterogeneous and predominantly peripheral enhancement (33 of 43 metastases, 77%). A pseudocystic pattern was seen in 13 of the 43 metastases (30%). Homogeneous tumors were made of smooth fibrous-like tissue without area of necrosis. Heterogeneous tumors contained varying degrees of necrosis and hemorrhage or gelatinous tissue. We found that primary and secondary hepatic leiomyosarcomas of the liver can exhibit different features. A pseudocystic pattern is uncommon. Furthermore, purely cystic tumors were not seen in our series.     

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。     

Pancreatitis complicated by gland necrosis: evolution of findings on contrast-enhanced CT

PURPOSE: The purpose of this work was to investigate the natural history of pancreatic necrosis on contrast-enhanced CT in patients managed nonoperatively. METHOD: A computer-based radiology information search revealed 32 patients with pancreatic necrosis who had had serial contrast-enhanced CT scans and were managed nonoperatively. There were 23 men and 9 women with a mean age of 51 years. One hundred forty-five contrast-enhanced CT scans were retrospectively reviewed for the location and extent of necrosis. The medical records of all patients were reviewed. RESULTS: The 32 patients had a mean Ranson clinical grade of 5.8 (range 3-8). Eighteen of these 32 patients were managed nonoperatively, and 14 patients required a necrosectomy after initial nonoperative management. In the 32 patients, the location of necrosis was in the head (3), body (6), tail (2), head/body (2), head/body/tail (9), body/tail (9), and head/tail (1). Extent of necrosis was 0-25% (9), 26-50% (6), 51-75% (6), and 76-100% (11). The extent of necrosis remained stable during follow-up in 22 (69%) patients and increased during follow-up in 10 (31%). Necrosectomy was performed in six (60%) patients in whom there was an increase in necrosis and eight (36%) patients in whom necrosis was stable. No patient had restoration of normal enhancement in an area that was previously necrotic. There were five patients who were managed nonoperatively (mean follow-up 318 days) in whom the necrosis eventually resorbed, forming a focal parenchymal cleft reminiscent of a scar. Five of the 32 patients died. CONCLUSION: Pancreatic necrosis as demonstrated by CT tends to remain stable in most patients treated nonoperatively. If the extent of necrosis increases, patients are more likely to require a necrosectomy. In some patients managed nonoperatively, the pancreatic necrosis will resorb, resulting in a fat-replaced cleft reminiscent of a scar.