CT of carcinoma of the pancreas: Different mode of spread according to lesion site

Thirty-seven patients were evaluated on computed tomography concerning the different modes of spread (peripancreatic vascular invasion and peritoneal implanting) in the pancreatic carcinoma arising in the four anatomic segments. Each was graded from 0 to 3. The median diameter of the adenocarcinomas was 4.5 cm. It was found that high propensity for vascular invasion occurred in the carcinomas of the body and neck, probably due to the anatomical proximity of the these structures, and the high incidence of intraperitoneal seeding in the carcinomas of the tail was found probably because of its intraperitoneal location.     

Acinar cell carcinoma of the pancreas: clinical and computed tomography manifestations

PURPOSE: Acinar cell carcinoma (ACC) is a subtype of pancreatic neoplasm sufficiently rare that its imaging has not been fully analyzed. The purpose of this article is to present the computed tomography (CT) appearance of ACC of the pancreas. METHODS: Clinical data and CT studies of 10 patients (7 male and 3 female) with pathologically proven ACC of the pancreas were reviewed. Among the CT features emphasized were the presence of a well-defined enhancing capsule, foci of internal calcification, intratumoral hemorrhage, presence of a central hypodense area, and degree of contrast enhancement. RESULTS: The presenting symptoms of ACC of the pancreas were nonspecific. An elevated serum level of alpha-fetoprotein, carcinoembryonic acid, and CA 19-9 was noted in 2 (20%), 1 (10%), and 3 (30%) patients, respectively. The tumor locations were in the uncinate process in 4 (40%), in the head and neck in 2 (20%), in the body in 1 (10%), and in the tail in 3 (30%) patients. The average tumor size was 7.2 cm (range: 3.3-18 cm). A well-defined enhancing capsule, internal foci of calcification, and intratumoral hemorrhage appeared in 6 (60%), 5 (50%), and 0 tumors, respectively. Eight (80%) tumors had a central hypodense area; of these, 4 (40%) tumors exhibited a hypodense area greater than 50% of the tumor. During dynamic CT in 8 patients, 6 tumors showed early arterial (EA) enhancement and persisted into the portal venous (PV) phase, whereas the other 2 tumors revealed enhancement in the EA phase and washout in PV phase. CONCLUSION: Acinar cell carcinoma typically presents as a sizable pancreatic mass with a well-defined enhancing capsule and internal calcifications. Significant central hypodensity is frequently present. Recognition of these features can provide clues to the CT diagnosis of ACC.     

胰腺腺泡细胞癌的CT特征分析

目的 探讨胰腺腺泡细胞癌(acinar cell carcinoma of pancreas,ACCP)的CT特征.方法 回顾性分析经手术证实的10例ACCP患者资料,患者均行CT平扫加动态增强扫描检查,分析其影像特征.结果 肿瘤发生在胰腺钩突4例、胰腺头部1例、胰腺颈部1例、胰腺体部2例、胰尾2例.平均直径6.7 cm.直径＞10 cm的2例为囊实性肿瘤,其余均为实性.肿瘤边界清晰,无浸润邻近器官、包绕血管表现.增强后动脉期和门静脉期肿瘤强化较周围胰腺弱.所有患者均可见完整或不完整的包膜线状强化.7例对胰(胆)管无明显侵犯;3例引起主胰管扩张,其中1例引起肝内、外胆管扩张.结论 ACCP在CT图像上具有特征性表现,有助于疾病的诊断.     

Choledochal cyst imaging by telepaque-enhanced computed tomography

A choledochal cyst is an uncommon anomaly of the biliary system requiring surgical intervention. A case of a choledochal cyst imaged by computed tomography following oral administration of cholangiography contrast material (Telepaque) is reported. Telepaque-enhanced computed tomography is an easy, noninvasive method to demonstrate pertinent preoperative anatomy in cases of choledochal cysts, and is especially useful in the pediatric patient.     

Mixture distribution analysis of a computer assisted diagnostic method for the evaluation of pulmonary nodules on computed tomography scan

RATIONALE AND OBJECTIVES: To compare the effectiveness of a new computational scheme for pulmonary nodule detection in computed tomography images against human observers. MATERIALS AND METHODS: The study involved evaluation of 81 potential nodules by four radiologists. Each radiologist separately evaluated the potential nodules and provided a confidence level for the presence of pulmonary nodules. Their performance was compared with that of the new computational scheme by mixture distribution analysis. RESULTS: Mixture distribution analysis of the results of the four radiologists demonstrated a relative proportion agreement of 0.84. The kappa statistic was used to compare the agreement of the computational scheme with the results of the four radiologists. A kappa value of .65 (se = .11) was shown to be significantly different from chance (P = .99). CONCLUSION: The new computational scheme correlates well with the radiologists' subjective rankings of pulmonary nodules on computed tomography scans and may prove a useful tool in the evaluation of algorithms for the screening and diagnosis of lung cancer.     

Multidetector helical computed tomography of the liver: comparison of hepatic enhancement using two different contrast media strategies

RATIONALE AND OBJECTIVES: The purpose of this study was to compare hepatic enhancement characteristics using two different contrast media injection protocols with multidetector helical computed tomography. MATERIALS AND METHODS: Twenty-three patients with known or suspected liver lesions scheduled to undergo biphasic hepatic multidetector helical computed tomography were randomized into one of two groups: (1) 150 mL of iopamidol (300 mgI/mL) at 5 mL/second, or (2) 100 mL of iopamidol (370 mgI/mL) at 4 mL/second. Unenhanced images were acquired initially, followed by both hepatic arterial phase (scan delay, 33 seconds) and portal venous phase (PVP; scan delay, 65 seconds) imaging. Three abdominal radiologists independently graded the images on a scale from 1-5 for enhancement and overall scan quality. Time-attenuation curves were generated from operator-defined region-of-interest measurements of liver parenchyma and aorta. RESULTS: Qualitatively, the three reviewers found no significant difference between the two study groups in terms of overall scan quality (P = .23) or aortic enhancement (hepatic arterial phase, P = .9; PVP, P = .24). However, liver enhancement during the PVP was considered to be less in the Isovue 370 group (P = .04). Quantitatively, during the hepatic arterial phase, there was no statistically significant difference between the two injection protocols comparing either aortic or hepatic parenchymal enhancement (P = .62 and .80, respectively). During the PVP, these differences were statistically significant, with both aortic and hepatic parenchymal enhancement lower in the Isovue 370 group (P < .01 and P = .04, respectively). CONCLUSION: It is important to consider the amount of iodine injected per second and the duration of the injection when setting up protocols to achieve target organ enhancement. 100 mL of iopamidol 370 at 4 mL/second can be used to obtain images of the liver with good diagnostic quality compared to more conventional protocols using 150 mL of iopamidol 300 at 5 mL/second. However, the degree of liver parenchymal enhancement during the PVP using the latter injection scheme is lower, which in turn could potentially reduce hepatic lesion conspicuity.     

Primary choriocarcinoma of the stomach and pancreas: CT findings

In this report we present the CT findings of two non-gestational,extragonadal choriocarcinomas, one arising within the stomach and one in the pancreas. These are rare tumours and a pancreatic primary site has not been previously described. Received 1 July 1997; Revision received 17 November 1997; Accepted 20 January 1998     

Leiomyosarcoma of the inferior vena cava: Angiographic and computed tomography findings

Leiomyosarcoma, a highly malignant tumor of the inferior vena cava, is rare. Only 55 cases have been reported in the world literature, and of these only 18 were evaluated with a special vascular procedure, either arteriography or inferior vena cavography. In two cases of leiomyosarcoma of the inferior vena cava, we performed arteriography and inferior vena cavography. In one, computed tomographic studies were also carried out. Cavography showed a lobulated filling defect in one case and complete caval occlusion with collateral circulation in the other. In the one case in which it was performed, computed tomography clearly demonstrated the tumor's size and its relationship to surrounding organs. Arteriographic studies, however, allowed only an indistinct delineation of the extent of tumor growth in one case. Venography followed by computed tomography should permit adequate assessment of most leiomyosarcomas of the inferior vena cava, with arteriography reserved for tumors involving the upper cava in which hepatic involvement must be evaluated.     

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。     

Renal replacement lipomatosis: ultrasonography and computed tomography findings

Replacement lipomatosis of the kidney is the result of severe atrophy or destruction of the renal parenchyma often caused by calculous disease with secondary marked proliferation of renal sinus, renal hilus, and perirenal fatty tissue. The diagnosis is difficult to establish with conventional radiographic methods. Although ultrasonography may show highly suggestive findings, computed tomography seems to be the most accurate method for demonstrating the distinctive features of replacement lipomatosis. Ultrasonographic and computed tomographic features in three cases of replacement lipomatosis of the kidney are reported. Received: 19 October 1998; Revision received: 8 December 1998; Accepted: 6 January 1999     

Lymphoepithelial cyst of the pancreas: radiological and pathological findings

We report a case of a rare lymphoepithelial cyst of the body of the pancreas that developed in a woman complaining of constipation for 15 years. Ultrasonography revealed a homogeneous isoechoic lesion, while CT demonstrated a polycystic homogeneous mass with central scar and calcification. Cytological investigation of a CT-guided biopsy permitted diagnosis of lymphoepithelial cyst. The patient was operated on and had an uneventful recovery. The histological finding was of a cyst wall lined with keratinised squamous epithelium surrounded by lymphoid tissue with reactive follicular hyperplasia. The radiological findings and differential diagnosis are discussed. Correspondence to: D. Regge     

胰腺实性假乳头状瘤MSCT双期扫描的诊断价值

目的:探讨胰腺实性假乳头状瘤(SPTP)的CT表现,提高对该病的诊断水平。方法:回顾性分析12例经手术及病理证实的SPTP。12例患者均行CT平扫及增强扫描。扫描参数为120kV,220mA,层厚5mm。动脉期延迟25～28s,实质期45～50s,门脉期80～85s。结果:10例为年轻女性,1例中年女性,1例男性,均无黄疸。12例表现为胰腺囊实性肿块,CT平扫表现为圆形、类圆形低密度或混杂密度肿块影,增强扫描后肿瘤实性部分及包膜可见强化,囊性部分无强化。结论:SPTP的CT表现有一定特征性。     

Computed tomography in spinal tuberculosis

Exhaustive ciinicoradiologic and computed tomographic (CT) analysis of 114 cases of spinal tuberculosis seen between January 1983 and January 1989 is presented. The mechanisms of the spinal involvement are reviewed. CT helped to diagnose cases of spinal tuberculosis in their initial stages. Inaccessible fixed areas of spine were seen with ease on axial sections of CT. The extent and anatomic depiction of soft-tissue involvement as depicted on CT helps surgeons choose the appropriate surgical approach, which may affect future spinal stability.     

Timing of exposure in angiographic computed tomography

Visualization of heart chambers or the abdominal arterial phase on one of two CT-scans was achieved in 89.4% of 169 injections (91 patients) using only 30 ml of contrast medium (370 mg iodine/ml), when the start of scanning was accurately timed at predicted bolus peak concentration. Normal arrival times and numer of transit cycles to the bolus concentration maximum in the right (RV) and left ventricle (LV) after injection of a small radionuclide bolus of technetium-99 m were related to the patient's heart rate (HR) in a group of 200 patients. For the RV, mean arrival times varied significantly between 2.31 (HR: 90–109 beats per minute) and 3.46 seconds (HR: 50–59 beats per minute), mean number of transit cycles between 4.1 and 3.5. For the LV, mean arrival times varied significantly between 6.92 (HR: 90–109 beats per minute) and 11.37 seconds (HR: 50–59 beats per minute), and the mean number of transit cycles between 11.5 and 10.7. Washout from the LV lasted between an average of 9.2 (HR: 90–109 beats per minute) and 8.5 cycles (HR: 50–59 beats per minute). Contrary to actual transit times, there was no significant difference in the number of transit heart cycles for heart rates between 60 and 109 beats per minute, so that to determine the scan starting time, the patient's cycle length (60 divided by heart rate) had only to be multiplied by the corresponding normal value of transit cycles, i.e., four for the RV, 11 for the LV, and 13 for the abdominal arteries. By applying the estimated values, the result was negative on two successive scans in only 10.6% because of failure in coordination on the part of the operators or bolus transit delays (due to severe heart failure, severe lung disease, recent thoracotomy, or small veins disease). With automatic triggering of the scanner by a timer and injector and with a flush of saline after injection, results can be further improved. Radionuclide studies supported by grant of the Internal Department of the Government of the Federal Republic of Germany     

Comparision between transrectal ultrasonography and computed tomography with rectal inflation of gas in preoperative staging of lower rectal cancer

Computed tomography with rectal air insufflation was compared with transrectal ultrasonography (TRUS) in 63 patients. The CT protocol involved pre- and postcontrast scans with 5 mm slice thickness following air insufflation in IV antiperistaltic agent. Of the patients, 79 % were scanned in the prone position. Results of the preoperative examinations were compared with the histological findings. The CT examination had an accuracy rate of 74 %, predicting perirectal spread with a sensitivity of 83 % and a specificity of 62 %, whereas the corresponding figures for TRUS were 83, 91 and 67 %. The accuracy, sensitivity and specificity of CT and TRUS for nodal involvement were 57, 56, 57, 66, 68 and 64 %-respectively. These findings confirm that TRUS is more accurate than CT in local tumour (T) staging and in detecting nodal (N) spread. However, the appropiate CT technique shows spread of tumour outside the rectal wall and locoregional lymph nodes with reasonable accuracy. Lymphatic spread correlated with nodal size. TRUS and CT correctly staged only 57 and 43 %, respectively, of cases with nodal metastases with maximum diameter of 5 mm. TRUS sometimes overstaged perirectal growth of tumour in 7 patients, due to inflammation (5 patients) or incorrect positioning of the ballon in relation to the tumour surface (2 patients). Received 11 April 1995; Revision received 22 January 1996; Accepted 24 January 1996     

The diagnosis of solitary primary reticulum cell sarcoma of the posterior fossa with computed tomography

Summary The CT findings in two surgically and histologically verified cases of primary reticulum cell sarcoma of the cerebellar hemisphere with secondary involvement of the cerebellopontine angle are presented. It is suggested that a correct diagnosis is possible by CT if the following criteria are present: 1. slightly increased attenuation of the mass on the precontrast scan; 2. mottled appearance of the definitely enhancing mass; 3. ill-defined borders on both the pre-and postcontrast scans; 4. degree of mass effect less than that expected from the size of the lesion; 5. involvement of the cerebellopontine angle without signs indicating an extra-axial origin of the tumor. These criteria reflect the gross and microscopic neuropathological features of the tumor.     

Computed tomography of the human developing anterior skull base

The ossification of the anterior skull base, especially the lamina cribrosa, has been studied by computed tomography and histopathology. Sixteen human fetuses, (referred to our laboratory for pathological examination after spontaneous abortion between 18 and 32 weeks of gestation) and three infants, (1, 2 and 6 years of age, respectively) were examined. The cartilaginous preformation of the anterior skull base creates a ‘pseudo-defect’ on CT in the coronal plane, even with ultra thin sections and high resolution CT. By the age of 6 years of life this ‘artefact’ is no longer, as the present ossification of the lamina cribrosa is, by that time, complete.     

The cranial computed tomographic findings in patients with pure sensory stroke

We reported three patients compatible with the clinical syndrome of pure sensory stroke (PSS). The computed tomography (CT) scan suggested the lesions responsible for the deficits were posterior thalamus, corona radiata, and parietal lobe. PSS could conceivably arise anywhere along the sensory systems and CT scan is reliable method for discussing the lesion responsible for PSS.