评估术前和术中动脉刺激及静脉采样在诊断和手术切除胰岛素瘤中的作用

动脉刺激和静脉采样（ASVS）方法首由Imamura应用于胃泌素瘤的检测,自动脉内注人胰泌素,然后来静脉血。几年后,Doppman应用动脉内钙负荷的原理来定位胰岛素瘤。日本Osaka大学医院于1993～1997年应用ASVS方法论断了6例胰岛素瘤,其中女5例,男1例,年龄37～67岁。病人入院前均有Whipple三联症和神经症状,经临床、超声和CT扫描、选择性动脉造影确诊为胰岛素瘤,作术前ASVS,将导管自右股动脉插入肝固有动脉、胃十二指肠动脉、脾动脉、肠系膜上动脉或胰十二指肠下动脉,一次注入葡萄糖酸钙0．025mEg／kg,在注射时和注射后30、60、…     

胰岛素瘤定位及定性诊断

胰岛素瘤是最常见的胰腺内分泌肿瘤,手术治疗是惟一的根治性治疗手段。胰岛素瘤定性诊断主要依据Whipple三联征和血清胰岛素与血糖比值,必要时可进行72h饥饿试验;定位诊断首选无创伤性检查手段,北京协和医院采用改良多层螺旋CT胰腺双期增强扫描准确率可达95%以上,术中超声检查联合术中探查定位准确率最高,可达100%。数字减影血管造影（DSA）、经皮经肝门静脉采血测定胰岛素（PTPC）和选择性动脉钙刺激静脉采血测定胰岛素（ASVS）等有创检查已基本不用。     

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目的 总结胰岛素瘤的诊断和治疗经验.方法 回顾性分析北京协和医院1953-2007年诊治404例胰岛素瘤的临床资料.结果 肿瘤直径＜2cm者占79.6%.36.2%的肿瘤位于胰头部,28.2%位于胰体部.35.6%位于胰尾部.18例(4.5%)为恶性胰岛素瘤,34例(9.0%)为多发性肿瘤.96.0%有典型的Whipple三联征.89.6%血胰岛素/血糖比值＞0.3.术前定位检查发现胰岛素瘤敏感性经腹超声检查36.8%,普通平扫CT24.7%,增强CT66.7%,多排螺旋CT胰腺灌注92.7%,MRI 31.6%,生长抑素受体显像33.3%,超声内镜(EUS)79.1%,选择性动脉造影(SAG)84.6%,经皮经肝门静脉置管取血(眦)测定胰岛素88.1%,动脉刺激静脉取血(ASVS)测定胰岛素87.0%.术中定位诊断方法的敏感性细针穿刺活检89.2%,术中超声(包括腹腔镜超声)检查90.0%.73.1%的病例可行肿瘤的局部摘除术.结论 多排螺旋CT胰腺灌注是目前胰岛素瘤术前定位诊断的首选方法.随着微创外科技术在胰腺外科中的应用,对部分条件适宜的病例可选用腹腔镜手术,但对多发胰岛素瘤仍应仔细开腹探查,避免遗漏病灶.     

胰岛素瘤的术中定位及其手术要领

在Bandng等于1922年发现胰岛素之后，RWilder于1927年首次诊治一倒高姨岛索血症患者，并经手术证实为胰腺恶性肿瘤伴肝转移。1929年RGraham首先成功切除了一良性胰岛素瘤治愈了患者，迄今手术切除肿瘤始终是胰岛素瘤治疗的主要方法。术中探查找到肿瘤是治疗获得成功的关键。选择性血管造影(SAG)和经皮肝穿刺门静脉置管分段取血(PTPC)技术曾促进了胰岛索瘤的定位。近年来，术中B超(IOUS)和动脉刺激静脉采血(ASVS)的应用使肿瘤定位又大大地前进了一步。本文试就胰岛索瘤的术中定位其及相关问题作一探讨。     

选择性动脉钙刺激后肝静脉血清胰岛素测定用于胰岛素瘤定位的研究

目的 探讨选择性动脉钙刺激后肝静脉血清胰岛素测定(ASVS)术前定位胰岛素瘤的临床应用价值.方法 对2000年5月至2010年6月收治的28例术前行ASVS检查的胰岛素瘤患者的病史资料进行回顾性分析.结果 28例患者中男12例,女16例,均有Whipple三联征表现.手术切除瘤体32枚,78.1%瘤体直径＜20 mm;术后病理均证实为胰岛素瘤,其中26例单发,2例多发.ASVS检查6例肠系膜上动脉出现最高峰值比,9例胃十二指肠动脉出现最高峰值比,6例脾动脉近段出现最高峰值比,6例脾动脉远段出现最高峰值比,1例检查结果阴性.ASVS最高峰比值数值的中位数、平均数分别为8.8倍、14.8倍.ASVS正确定位25例,错误定位2例,1例检查结果阴性,ASVS准确率为89.3%(25/28),高于同组CT、MRI(CT、MRI定位准确率分别为56.5%,60.0%);ASVS敏感度为96.2%,高于同组CT、MRI(CT、MRI敏感度分别为69.6%,75.0%).结论 ASVS术前定位胰岛素瘤较CT、MRI有优势,但ASVS创伤大,应作为CT、MRI等常规影像学检查阴性时定位胰岛素瘤的补充定位手段.

Abstract：

Objective To evaluate the clinical value of selective intra-arterial calcium stimulated venous sampling ( ASVS) for the localization of pancreatic insulinoma preoperatively.Methods The clinical data of 28 insulinoma patients admitted from May 2000 to June 2010 in Ruijin Hospital undergoing selective intra-arterial calcium stimulated venous sampling with diagnosis of insulinomas before surgery were analyzed retrospectively.Results There were 12 males and 16 females.All the patients had Whipple's triad, and with proved insulinomas by postoperative pathology.There were 26 cases of single insulinoma and 2 cases of multiple insulinomas with altogether 32 insulinomas resected.78.1% of insulinomas were less than 20 mm.All patient were examined by selective intra-arterial calcium stimulated venous sampling.The peak ratio of insulin to the baseline after calcium stimulation appeared at the superior mensenteric artery (SMA) in 6 cases, and the peak ratio of insulin to the baseline after calcium stimulation appeared at gastroduodenal artery(GDA), proximal splenic artery (SAP) and distal splenic artery (SAD) in 9 cases, 6 cases and 6 cases respectively; Selective intra-arterial calcium stimulated venous sampling accurately located 25 cases, and selective intra-arterial calcium stimulated venous sampling located 2 cases wrongly.In one patient, the selective intra-arterial calcium stimulated venous sampling was falsely negative.The mean and median peak ratio of insulin to the baseline after calcium stimulation were 8.8 folds and 14.8 folds respectively.Accurate rate of selective intra-arterial calcium stimulated venous sampling was 89.3% (25/28) and it was higher than that of computed tomography (CT) (56.5% ) , magnetic resonance imaging (MRI) (60.0%).Sensitivity of selective intra-arterial calcium stimulated venous sampling was 96.2%, which was higher than that of computed tomography ( 69.6% ) , magnetic resonance imaging (75.0% ).Conclusion Selective intra-arterial calcium stimulated venous sampling is superior to computed tomography, or magnetic resonance imaging as a preoperative localizing tool for insulinomas, since this procedure is invasive it should be used when other preoperative morphologic studies (computed tomography or magnetic resonance imaging) failed.     

动脉内钙刺激试验中静脉血样定位胰腺胰岛素瘤的价值

术中有经验的双手扪摸和术中 B超扫描几乎可定位绝大部分的胰岛素瘤病例。在术前的定位检查中 ,动脉内钙注射和肝静脉血采样是一个较好的方法(ASVS)。作者复习 1991～ 2 0 0 0年 2 0例该检查的结果 ,2例拒绝手术 ,余 18例均经手术证实为胰岛素瘤。11例在ASVS前均未作出定位诊断。术前其他检查有 CT(2 0例 )、B超 (9例 )、磁共振成像 (8例 )、选择性动脉造影 (6例 )和内镜超声扫描 (8例 )。ASVS操作步骤按 Doppman所述 (Radiology1991;178:2 37)。经股动脉置管分别至胃十二指肠、肠系膜上、脾和肝动脉。取葡萄糖酸钙 (10 %溶液 ) 0 .…     

胰岛素瘤的诊断和外科治疗

目的探讨胰岛素瘤的诊断和外科治疗方法。方法回顾性分析经手术和病理确诊的55例胰岛素瘤患者的临床资料。结果 7例为无功能性,48例(87.27%)功能性胰岛素瘤均有典型的Whipple三联征表现,且血胰岛素/血糖比值(IRI/G)0.3。术前超声,CT,MRI,内镜超声(EUS),术中超声和选择性动脉造影(DSA)诊断的阳性率分别为83.64%(46/55),62.07%(18/29),40.00%(4/10),100%(8/8),90.00%(9/10)和40.00%(2/5)。胰岛素瘤剜除术48例次,胰体尾切除术5例,胰体尾联合脾切除术3例,胰腺中段切除术1例,胰十二指肠切除术1例;肿瘤直径小于或等于2 cm者占95.00%(57个)。23.33%(14个)的肿瘤位于胰头部,33.33%(20个)位于胰体部,43.33%(26个)位于胰尾部,3例(5.46%)为多发性肿瘤。病理诊断均为胰岛素瘤,无恶性者。术后无低血糖症状发作,发生胰瘘1例。结论 Whipple三联征和IRI/G0.3可作为胰岛素瘤定性诊断的依据。联合应用超声,CT,MRI和内镜超声多种方法进行术前定位。内镜超声在胰岛细胞瘤定位诊断中的阳性率最高;术中超声是有效的定位方法。肿瘤剜除术是胰岛素瘤的最佳治疗方法。     

非胰岛素瘤胰源性低血糖综合征

胰源性低血糖多由于胰岛素瘤引起 ,但也有非胰岛素瘤所致者。凡影像学检查未能显示胰岛素瘤 ,72小时禁食试验阴性 ,但选择性动脉钙刺激试验阳性 ,胰体切除标本示胰岛增生或成胰岛细胞增殖症 ,上述情况称之为非胰岛素瘤性低血糖综合征 (NIPHS)。作者自1996～ 1999年共收治 10例 NIPHS患者 ,年龄平均 4 7岁(16～ 78岁 ) ,男性 7例。腹部 B超和螺旋 CT扫描均呈阴性 ,腹腔动脉造影也正常。但选择性动脉钙刺激试验均呈阳性 ,即自脾动脉、肠系膜上动脉或胃十二指肠动脉内注入钙 0 .0 12 5 mmol/kg,右肝静脉内胰岛素浓度增加 2倍或以上 (正常…     

胰岛素瘤23例诊治分析

目的总结探讨胰岛素瘤的诊断和外科治疗方法。方法回顾性分析我院1998~2005年23例胰岛素瘤的临床资料。结果本组19例有典型Whipple三联征。术前B超、CT、选择性动脉造影诊断的阳性率分别为47.8%(11/23)、64.7%(11/17)、85.7%(6/7)。行单纯肿瘤摘除术14例、局部切除术6例、胰体尾部切除术1例、胰十二指肠切除术1例、腹腔镜下胰岛素瘤摘除术1例。术后血糖均恢复正常,但有2例发生胰漏并发症,1例发生假性囊肿,2例伴有精神症状者术后症状无改善。结论Whipple三联征和血清胰岛素与血糖比值(IRI/G)>0.3对于胰岛素瘤有诊断意义。术前B超、CT、选择性动脉造影用来明确定位。单纯肿瘤摘除术是最常用的手术方法,术中超声及血糖监测的应用有重要意义。     

胰岛素瘤的定位

尽管有很多检查方法，诸如术前B超扫描、CT、磁共振成象、核素扫描、经肝静脉插管、钙刺激血管造影（经肝静脉插管），仍有40％胰岛素瘤不能检出。选择性动脉造影的术前定位成功率也仅60％，惜这一方法是损伤性的，费用昂贵。作者分析加州大学医院于1975～1998年收治的66例胰岛素瘤的资料，比较各种定位方法的结果。男24例，女42例，平均43．9岁，其中8例为多发性内分泌肿瘤1型（MENI）。结果（一）肿瘤大小和部位50例单个肿瘤的直径平均为1．8cm．其中13例＜Icm。34例肿瘤位于胰头部，38％位于胰体，28％位于胰尾。1例女性病人有异位肿…     

Insulinoma: Selective arterial calcium injection performed to confirm localization and complete resection

A case of insulinoma is reported in a patient in whom selective arterial calcium injection (SACI) tests were performed both to confirm tumor localization before surgery and to confirm complete tumor removal during surgery. An 18-year-old woman with hypoglycemic episodes was diagnosed with an insulinoma in the pancreatic body demonstrated by celiac arteriography. In a preoperative SACI test, calcium was injected into the splenic artery (SpA), gastroduodenal artery (GDA), and superior mesenteric artery (SMA). Serum immunoreactive insulin (IRI) and proinsulin levels were measured in hepatic venous samples. IRI was markedly increased after the injection of calcium into the GDA and SMA, while there was no response in IRI levels when calcium was injected into the SpA. Therefore, no occult insulinoma was revealed in the distal area fed by the SpA, although the presence of insulinoma was uncertain in the proximal pancreas. In the intraoperative SACI test, calcium was injected into the celiac artery. Insulin (determined by enzyme immunoassay) and proinsulin levels were measured in portal venous samples before and after resection of the tumor. After resection, these levels decreased in response to the calcium stimuli, confirming complete removal of the insulinoma. The SACI test was helpful to localize the insulinoma and was useful to confirm the complete removal of the tumor.     

Evaluation of preoperative and intraoperative arterial stimulation and venous sampling for diagnosis and surgical resection of insulinoma

BACKGROUND: The precise intraoperative localization of insulinoma is essential for successful surgical treatment. In addition to various imaging modalities developed recently, arterial stimulation and venous sampling (ASVS) has also been used for tumor localization. METHODS: Preoperative and intraoperative ASVS procedures were performed in 6 patients with insulinoma. Intraoperative ASVS was performed before and after tumor resection. Immunoreactive insulin (IRI) concentrations and the IRI ratio (IRI concentration at each time interval after calcium injection/baseline IRI concentration) were determined by the conventional or a quick IRI method. RESULTS: The site of the tumor was identified preoperatively in all patients. The peak of the IRI ratio varied widely, but setting the cutoff value at 3.0 clearly differentiated peak IRA ratios in feeding arteries from those of nonfeeding arteries. Intraoperative ASVS showed a similar elevation of IRI levels, but the elevation disappeared after tumor resection in all but 1 patient. In 2 patients, resection of the tumor was confirmed during surgery by measuring IRI levels by the quick IRI method. CONCLUSIONS: A combination of ASVS and conventional imaging modalities is useful for precise localization of insulinoma. Resection of the tumor can be confirmed intraoperatively by comparing IRI levels associated with preoperative and postresective ASVS.     

Value of intra-arterial calcium stimulated venous sampling for regionalization of pancreatic insulinomas

BACKGROUND: Intra-arterial calcium stimulation with hepatic venous sampling (ASVS) for insulin gradients has been reported to be the most sensitive preoperative localizing technique for insulinomas. We reviewed our experience with ASVS to localize and guide the treatment of insulinomas over the past decade. METHODS: Eighteen patients who underwent ASVS before surgical exploration for insulinoma were studied. The accuracy of ASVS was compared with intraoperative findings and other localizing studies. RESULTS: There were no complications arising from the procedures. A more than 2-fold step-up in insulin level 30 to 60 seconds after injection to at least 1 feeding artery was observed in 16 patients. Fourteen of the 16 solitary tumors (87.5%) were correctly located; 100% (6/6 tumors) at the head and 80% (8/10 tumors) at the body/tail. The overall accuracy of this test was 89%, compared with 11%, 33%, 38%, and 63% of ultrasonography, computed tomography, magnetic resonance imaging, and endoscopic ultrasonography, respectively. Six enucleations and 10 distal resections were performed, which included 2 laparoscopic procedures. The combination of intraoperative ultrasonography with preoperative ASVS identified all tumors. CONCLUSIONS: ASVS is the most accurate preoperative localization tool for the localization of insulinomas and, in combination with intraoperative ultrasonography, can enhance surgical success.     

The Role of Intra-Arterial Calcium Stimulation Test with Hepatic Venous Sampling (IACS) in the Management of Occult Insulinomas

Background Occult insulinomas remain a clinical challenge. Specifically designed protocols are necessary to aid detection and facilitate a focused pancreatic exploration. Methods Seventeen non-multiple endocrine neoplasia (non-MEN) patients referred to this medical center in the past 10 years because of equivocal diagnosis, failure of previous operation or difficulty in localization for insulinomas were studied. A routine intra-arterial calcium stimulation test with venous sampling (IACS test) was done for lesion localization. An exploratory laparotomy with intraoperative ultrasound (IOUS) examinations was performed. Results Preoperative imaging (sonography, high-resolution computed tomography scan, and magnetic resonance imaging) found six insulinomas, and IOUS found an additional six in the pancreatic regions; all were compatibly indicated by the IACS test. The remaining five patients with occult lesions by IOUS were treated by 40% (1) or 60–70% (4) distal pancreatectomies when insulin gradients were demonstrated on calcium stimulation to the splenic or to the superior mesenteric artery, respectively, and nesidioblastosis was found in each pathology examination. There were no complications related to the arterial stimulation and venous sampling (ASVS) test. No patient had recurrent hyperinsulinism, permanent morbidity, or mortality from surgery. Conclusions IACS test helps in the diagnosis of equivocal pancreatogenous hypoglycemia, indicating the pancreatic region of priority exploration and guiding a pancreatic resection.     

Spleen-preserving laparoscopic distal pancreatectomy after division of the splenic vessels

A 37-year-old woman with a history of syncope was hospitalized with a diagnosis of hypoglycemia due to insulinoma. Computed tomography (CT) and magnetic resonance imaging revealed an enhanced solid mass, 1.5 cm in diameter, at the tail of the pancreas. Angiography via the splenic artery revealed a hypervascular mass. Because the tumor was located deep in the pancreatic parenchyma, laparoscopic distal pancreatectomy was performed. The pancreas was exposed by dissecting the greater omentum, and the tumor was located by intraoperative ultrasonography. After division of the splenic artery, the pancreas, main pancreatic duct, and splenic vein were transected with an endoscopic linear stapler. The pancreatic pedicle was divided at the splenic hilum to preserve the spleen. The postoperative course was uneventful except for the appearance of splenic infarction on a CT scan 2 weeks after surgery but without any overt symptoms. Spleen-preserving laparoscopic distal pancreatectomy by division of splenic vessels is a feasible treatment option for benign pancreatic disease.     

74例胰岛素瘤诊断和手术治疗方法的探讨

目的 :总结胰岛素瘤诊断和手术治疗的经验。方法 :对 1 966年 7月～ 2 0 0 1年 7月我院手术治疗、并有病理诊断的 74例胰岛素瘤病人进行回顾性研究。结果 :本组病人均符合Whipple三联征 ,至少有一次IRI G >0 .3。52 .70 %病人曾被误诊 ,仅 2 0 .2 7%病人在发病一年内得到正确诊断 ,平均病程 3 .36年。B超和EUS定位阳性率不高 ,CT和MRI正确检出率分别为 63.41 %和 63.64% ,ASVS正确检出率达 90 %。单发胰岛素瘤为 66例 (89.1 9% ) ,多发胰岛素瘤 2例 (2 .70 % ) ,增生 4例 (5 .41 % ) ,恶性胰岛素瘤 2例 (2 .70 % )。良性胰岛素瘤中 85 .2 7%直径≤ 2cm。单纯摘除是主要手术方法 ,88.52 %肿瘤切除后 30min血糖上升至正常水平以上 ,余于术后 2h内恢复至正常水平以上。 97.2 6 %的病人术后发生高血糖 ,一般在术后一周血糖恢复正常。最常见的术后并发症为胰瘘 (2 7.2 7% )和胰腺炎 (5 .1 9% )。结论 :胰岛素瘤是最常见的胰腺内分泌肿瘤。CT可作为首选的定位方法 ,对其他方法难以发现的肿瘤可行ASVS。手术是治愈胰岛素瘤的主要方法 ,但需注意胰瘘的发生     

A prospective evaluation of laparoscopic exploration with intraoperative ultrasound as a technique for localizing sporadic insulinomas

BACKGROUND: Preoperative imaging studies localize insulinomas in less than 50% of patients. Arteriography with calcium stimulation and venous sampling (ASVS) regionalizes greater than 90% of insulinomas but requires specialized expertise and an invasive procedure. This prospective study evaluated laparoscopic exploration with IOUS compared with the other localization procedures in patients with a sporadic insulinoma. METHODS: Between March 2001 and October 2004, 14 patients (7 women and 7 men; mean age, 53) with an insulinoma were enrolled in an IRB-approved protocol. Computed tomography, magnetic resonance imaging, ultrasound scan, and arteriography with calcium stimulation and venous sampling were performed preoperatively. A surgeon, blinded to the results of the localizing studies, performed a laparoscopic exploration with intraoperative ultrasound (IOUS). At the completion of the exploration, the success of laparoscopy for localization was scored, and the tumor was resected. RESULTS: Twelve of 14 tumors were localized successfully before laparoscopy (noninvasive, 7 of 14; invasive, 11 of 14). Laparoscopic IOUS localized successfully 12 of 14 tumors. All lesions were resected, and all patients were cured (median follow-up, 36 months). CONCLUSION: Laparoscopic IOUS identified 86% of tumors. The authors consider laparoscopic IOUS to be equivalent to ASVS in localizing insulinomas. Further study is therefore warranted to determine the role of laparoscopy with IOUS in the localization and treatment algorithm for patients with sporadic insulinoma.     

Intraoperative Ultrasound with Palpation is Still Superior to Intra-arterial Calcium Stimulation Test in Localising Insulinoma

Aim This study assessed the sensitivities of preoperative localisation modalities such as computed tomography (CT), magnetic resonance imaging (MRI), arteriography and arterial stimulation venous sampling (ASVS) using serum insulin and C-peptide gradients to intraoperative techniques in localising insulin-secreting tumours in our institution. Methods Fourteen patients with proven insulinoma, aged 20–66 years, who presented from 1997 to 2004, were studied retrospectively. All patients underwent ASVS where C-peptide and/or insulin gradients were calculated. The results were compared with the preoperative findings of CT, MRI, arteriography, as well as intraoperative ultrasound and palpation. Results Intraoperative ultrasound with palpation correctly localised 10 of the 11 tumours with a sensitivity of 91%. Sensitivities of other localisation techniques were lower: 31% by CT, 50% by MRI, and 46% by arteriography. ASVS with insulin gradients alone allowed accurate localisation in 40% of patients while localisation using only C-peptide gradients of more than 2 was 43%. The insulinomas, measuring 10–30 mm, were successfully removed in 13 patients—6 from the body, 4 from the tail, 2 from the head and 1 from the junction of the body and tail. All except 1 were cured by selective surgery and remained free of hypoglycaemia over the next 2–60 months of follow-up. One patient had left lobectomy due to liver metastases from a malignant insulinoma and remained asymptomatic with medical therapy. Conclusions Intraoperative ultrasound with palpation is a highly sensitive method for the localisation of insulinoma compared with other preoperative localisation techniques.     

Localization of islet-cell hyperplasia: value of pre- and intraoperative arterial stimulation and venous sampling

Arterial stimulation and venous sampling was effective in the localization of -cell hyperplasia of the pancreas in the islets of Langerhans in an 84-year-old woman. The patient presented with repeated episodes of unconsciousness and hypoglycemia. She was first suspected of having insulinoma, but diagnostic imaging failed to reveal any tumors. Arterial stimulation and venous sampling (ASVS) and percutaneous transhepatic portal venous sampling (PTPS) were performed to localize the tumor. By ASVS, increases in immuno reactive insulin (IRI) were noted in renal vein blood samples (because a splenorenal shunt was present) after splenic arterial stimulation and venous sampling, and PTPS revealed a stepup in IRI from splenic venous blood samples. Preoperative diagnosis suggested -cell hyperplasia in the pancreas tail. Intraoperative ultrasound failed to find a tumor. Intraoperative ASVS showed the site of increase IRI as the pancreas tail, so distal pancreatectomy and splenectomy were performed. However, hypoglycemia was observed constantly after this operation. Relaparotomy, causing additional resection, was conducted to confirm the precise location and to remove the residual -cell hyperplasia of the pancreas. At the second resection, the existing part of -cell hyperplasia was confirmed through intraoperative ASVS, and additional resection of the pancreas body and neck was performed. At this time, complete removal of the residual -cell hyperplasia was confirmed through ASVS. The hypoglycemia and impaired consciousness disappeared after the operation, and the patients blood sugar level was maintained at a normal level. Pathological findings revealed islets of Langerhans hyperplasia extending to 1cm in the pancreas tail region. We conclude that pre- and intraoperative ASVS is a useful test for -cell hyperplasia, which is difficult to diagnose through ordinary imaging techniques.