Solitary fibrous tumor of the pleura: MR appearance and enhancement pattern

PURPOSE: The aim of the current study was to characterize the MR appearance of solitary fibrous tumor of the pleura (SFTP). METHOD: Twenty-two consecutive patients with histologically confirmed SFTP were retrospectively evaluated with MRI. RESULTS: Tumors demonstrated low signal intensity (n = 18, 82%), iso signal intensity (n = 2, 9%), and high signal intensity (n = 2, 9%) on T1-weighted images. On T2-weighted images, tumors were observed as low signal intensity (n = 10, 45%), high signal intensity (n = 2, 9%), and mixed signal intensity (n = 10, 45%). Solid component in the proliferation of tumor cells corresponded to low signal intensity in 12 tumors (55%) on T2-weighted images. On gadolinium-enhanced T1-weighted images, inhomogeneous enhancement (n = 18, 82%), nodular enhancement (n = 6, 27%), and homogeneous enhancement (n = 4, 18%) were observed. The enhanced lesion within the tumors had dense tumor tissue and dilated microvessels in the pathologic specimen. CONCLUSION: SFTP shows variable appearance and enhancement pattern on MRI according to morphologic tumor heterogeneity.     

心脏原发恶性肿瘤CT及MRI表现

目的:了解心脏原发恶性肿瘤的CT、MRI表现,旨在提高诊断及鉴别诊断。材料和方法:12例经病理证实心脏恶性肿瘤的CT及MRI资料进行回顾性分析。其中5例行胸部CT平扫加增强扫描。9例做心脏MR检查,其中7例行动态增强扫描。结果:发生部位以右心房最多见(6/12)。跨心腔生长或累及邻近大血管及心包常见(10/12)。伴有心包和胸腔积液(9/12)。肿瘤多以中度不均匀强化为主,血管肉瘤内见同血管强化一致条状影,横纹肌肉瘤呈后期明显均匀强化。肿瘤MR信号以T1WI等略低信号,T2WI为混杂高信号表现为主,而恶性纤维组织细胞瘤T2WI呈明显低信号较特征。结论:心脏恶性肿瘤具有一般恶性肿瘤侵袭性生长之特点,CT、MRI评价病变范围、组织特征具有优势,有助于诊断及治疗方案实施,进一步组织学定性、鉴别有困难。     

Desmoplastic small round cell tumor: imaging findings associated with clinicopathologic features

PURPOSE: To describe imaging findings of desmoplastic small round cell tumor (DSCRT) and to clarify the relation between radiologic appearances and clinicopathologic features. MATERIALS AND METHODS: CT scans and MRI examinations of four male patients with histologically confirmed DSCRT (mean age = 20 years) were retrospectively analyzed. RESULTS: The common imaging finding was multiple peritoneal masses with regular contour situated within mesentery. Tumors showed central low attenuation in 75% of patients on nonenhanced CT. All tumors showed inhomogeneous enhancement on CT. Small foci of punctate calcification were identified in a part of the tumor in all patients. Bone metastases were identified on enhanced CT in two patients 2 and 8 months after diagnosis, respectively. Pleural dissemination was identified in all patients, and one patient had double-sided dissemination. T2-weighted MRI showed inhomogeneous high signal intensity, and small cysts were identified in two patients. Fluid-fluid levels were identified in six tumors on T2-weighted images, which suggested the presence of hemorrhage. Tumors had inhomogeneous signal intensity low or isointense relative to skeletal muscle on T1-weighted images. Two lesions exhibited inhomogeneous enhancement with central low intensity consistent with necrosis. CONCLUSION: Imaging studies can depict disseminated characteristics and disease extent during the clinical course of DSRCT.     

Pulmonary Aspergillus chest wall involvement in chronic granulomatous disease: CT and MRI findings

Pulmonary Aspergillus infection in patients with chronic granulomatous disease tends to involve the chest wall and consequently carries a high mortality rate. We report the findings of computed tomography (CT) and magnetic resonance imaging (MRI) in three such cases. One patient underwent both CT and MRI, one, CT only, and one, MRI only. In all three, both CT and MRI demonstrated pulmonary consolidations with direct extension to the adjacent chest wall. In both patients who were examined by CT, scans revealed permeative osteolytic changes of adjacent rib or spine compatible with osteomyelitis. In both patients who were examined by MRI, adjacent chest wall involvement was depicted on T1-weighted images and showed increased signal intensity on T2-weighted images. In one of these patients, the chest wall lesion was well defined on T2-weighted images, an appearance compatible with abscess. Epidural extension was demonstrated on MRI in the other patient, who later developed paraparesis. We suggest that CT and MRI have a complementary role in evaluating chest wall invasion by pulmonary Aspergillus infection in chronic granulomatous disease.     

Hemangiomas of skeletal muscle: MR findings in five patients

Skeletal muscle hemangiomas are uncommon tumors of young adults. More than 90% are misdiagnosed preoperatively. Plain-film examinations, bone scans, CT studies, and angiography may not always be specific for this tumor. Seven MR examinations were performed in five young adult patients with pathologically proved skeletal muscle hemangiomas. All five hemangiomas showed high signal intensity on both T1- and T2-weighted images. The signal intensity in these tumors was less than that of subcutaneous fat on relatively T1-weighted images and greater than that of fat on relatively T2-weighted images. Four tumors had a serpiginous pattern. Four patients had focal muscle atrophy. Three patients had all three findings (high signal intensity on both T1- and T2-weighted images, serpiginous pattern, and associated focal muscle atrophy) while the other two patients had at least two of the three findings. These three patients did not undergo angiography or needle biopsies before surgery because the MR findings were highly suggestive of hemangioma. Our experience with this small series of patients suggests that skeletal muscle hemangiomas have a consistent appearance on MR. MR may be able to contribute significantly to the preoperative diagnosis of this tumor and may also supply valuable information about the extent of the lesion.     

MR imaging of solitary pulmonary lesion: emphasis on tuberculomas and comparison with tumors

The aim of this study was to determine whether solitary pulmonary tuberculoma and malignant tumor can be differentiated on the basis of magnetic resonance (MR) signal intensity. Twenty-eight patients with solitary pulmonary lesions were prospectively studied with MR imaging: T1-weighted, enhanced T1-weighted, proton density-weighted, and T2-weighted spin echo images were obtained. The confirmation methods used were computed tomography (CT)-guided biopsy in seven patients with lung cancer and four patients with tuberculosis; surgery in ten patients with lung cancer and five patients with tuberculosis; and laboratory data in two patients with tuberculosis. Morphologic features and MR signal intensity were examined in detail. As the test for detection of tuberculoma, signal difference on T2-weighted images was carefully analyzed. The signal intensity ratio of the nodule to thoracic muscle signal intensity was measured. The signal intensities obtained from the lung cancers and tuberculomas were variable on pre-and post-enhanced T1-weighted images and proton density-weighted images. Masses were hypointense in 2 of 17 patients with lung cancer and in 9 of 11 patients with tuberculoma on T2-weighted images (sensitivity 82%, specificity 89%, accuracy 87%). The mean signal intensity ratios of the tuberculomas to muscle were significantly lower than those of malignant tumors on T1-weighted, enhanced T1-weighted, proton density-weighted, and T2-weighted images (P < 0.0001). After gadolinium-DTPA enhancement, 2 malignant tumors and 7 tuberculomas showed a marginal rim enhancement pattern, whereas 15 malignant tumors and 2 tuberculomas revealed a diffuse enhancement. The results of MR imaging were consistent with those of CT in 84% of the patients. MR imaging is a helpful adjunctive method in terms of differentiating a tuberculoma from a malignant tumor.     

骨原发性恶性纤维组织细胞瘤的MRI表现及其诊断价值

目的:探讨骨原发性恶性纤维组织细胞瘤(MFH)的MRI表现及其诊断价值。方法:对5例手术病理或穿刺活检证实的骨原发性MFH 的MRI 表现、临床及病理学资料进行回顾性分析,并复习相关文献。结果: 5 例骨原发性MFH发生于股骨下端3例,发生于眶壁及脊柱各1例。MR平扫肿瘤组织呈不均匀长或稍长T1、长或稍长T2 信号,与正常骨组织分界清晰。含纤维组织成分较多的纤维瘤型恶性纤维组织细胞瘤T2WI则呈低信号强度。静脉注入Gd DTPA后,T1WI脂肪抑制序列肿瘤组织呈明显不均匀强化。结论:骨原发性MFH少见,易误诊为其他恶性骨肿瘤。MRI能清楚显示骨原发性MFH的病变部位、范围、轮廓以及与邻近组织结构的关系,但没有特异性,其最后确诊需临床、影像和病理三者结合,病理检查是确诊的主要手段。     

Retroperitoneal ganglioneuroma in children: CT and MRI features with histologic correlation

Objective

To demonstrate the CT and MRI features with histologic correlation of retroperitoneal ganglioneuromas in children.

Methods

The diagnostic images (seventeen CT scans and five MR scans) in 17 children with retroperitoneal ganglioneuroma confirmed by operation and histopathology were retrospectively reviewed, and correlated to the histologic findings.

Results

All tumors presented as an oval-shaped, well-defined mass on both CT and MR images. On unenhanced CT images, calcification was detected in six masses (35.3%), and predominantly low attenuation with the CT value ranged from 22 to 38 HU (mean 29.5 HU) in all the tumors. The tumors with CT value less than 30 HU had a relatively larger amount of myxoid stroma on histopathologic sections than those with CT value more than 30 HU. Tumors showed homogeneous low signal intensity on T1-weighted images and inhomogeneous high signal intensity with interlaced or nodular low signal intensity on T2-weighted images. The post-contrast enhancement on both CT and MR images was lacking or slight in early phase, but moderate or marked in late phase. The inhomogeneous high signal intensity on T2WI, as well as the delayed enhancement corresponded to a large amount of myxoid stroma and a relatively small number of cellular components in tumors.

Conclusion

An oval shape, well-defined margin, low attenuation on CT, inhomogeneous hyperintensity on T2WI, and delayed moderate or marked enhancement are typical features of retroperitoneal ganglioneuroma in children. The imaging features correlated well to the histologic findings.     

MRI of malignant fibrous histiocytoma of soft tissue: analysis of 13 cases with pathologic correlation

We reviewed the magnetic resonance (MR) appearances of 13 malignant fibrous histiocytomas (MFH) of soft tissue and correlated each with the respective lesion's histopathology. The MR images were evaluated for signal intensity on T1- and T2-weighted spin echo sequences, homogeneity of the lesion, presence of internal low signal septations, and margin definition. Histologic subtypes of MFH included storiform-pleomorphic, giant cell, myxoid, and inflammatory. We could not establish a correlation between MR appearance and histopathology. Instead, our series exhibited general features suggestive of malignant soft tissue neoplasms, namely poor margin definition, internal low signal septation, and heterogeneous high signal intensity on T2-weighted images.     

Differentiation of phyllodes breast tumors from fibroadenomas on MRI

OBJECTIVE: The purpose of our study was to evaluate the MRI appearance of phyllodes breast tumors and to differentiate them from fibroadenomas. MATERIALS AND METHODS: MR images were obtained on a 1.5-T imager. T1- and T2-weighted sequences and dynamic 2D fast-field echo T1-weighted sequences were performed. MR images of 23 patients with 24 phyllodes breast tumors (one malignant, 23 benign) were analyzed with respect to morphology and contrast enhancement. The tumors were compared with the MRI appearance of 81 fibroadenomas of 75 patients. RESULTS: Well-defined margins were seen in 87.5% of the phyllodes tumors and 70.4% of the fibroadenomas, and a round or lobulated shape in 100% and 90.1%, respectively. A heterogeneous internal structure was observed in 70.8% of phyllodes tumors and in 49.4% of fibroadenomas. Nonenhancing internal septations were found in 45.8% of phyllodes tumors and 27.2% of fibroadenomas. A significantly greater increase in signal was seen on T2-weighted images in the tissue surrounding phyllodes tumors (21%) compared with fibroadenomas (1.2%). Most of both lesions appeared with low signal intensity on T1- and T2-weighted images. After the administration of contrast material, 33.3% of phyllodes tumors and 22.2% of fibroadenomas showed a suspicious signal intensity-time course. CONCLUSION: Phyllodes breast tumors and other fibroadenomas cannot be precisely differentiated on breast MRI. Phyllodes tumors have benign morphologic features and contrast enhancement characteristics suggestive of malignancy in 33% of cases.     

MR imaging of extraabdominal desmoids: differentiation from other neoplasms.

A retrospective review of MR images of 36 patients with histologically proved extraabdominal desmoids was done to define the MR characteristics of these tumors and to determine if MR could be used to differentiate desmoids from other benign and malignant soft-tissue neoplasms. The desmoids evaluated included eight primary and 30 recurrent lesions. Our study was conducted in parallel with another study in which the MR appearance of 95 benign and malignant soft-tissue masses was evaluated, and the MR images of these masses were compared with our findings. The four desmoids from that study are included in our data. The signal intensity of the tumor on T1- and T2-weighted images was graded relative to the intensities of muscle and fat. Homogeneity, margin, neurovascular and bone involvement, and fibrosis (low-signal regions within the tumor on both T1- and T2-weighted images) were evaluated. On MR imaging, the desmoids showed inhomogeneous signal (97%), poor margination (89%), neurovascular involvement (58%), and bone involvement (37%). Fibrosis was present in 88% of primary desmoids and 90% of recurrent ones, and intermediate signal (greater than that of muscle and less than that of fat) was present in 75% and 50% of these, respectively. Our results show that the MR features of desmoids have characteristics that are commonly found in malignant tumors (inhomogeneous signal, poor margination, and neurovascular involvement). MR features of desmoids that distinguish them from malignant neoplasms are the presence of fibrosis and intermediate signal in the regions of the tumor.     

Malignant fibrous histiocytoma of bone: conventional X-ray and MR imaging features

Objective. To evaluate the conventional X-ray and MR imaging features of malignant fibrous histiocytoma (MFH) of bone. Design. MRI examinations and conventional radiographs were reviewed in 39 patients with biopsy-proven MFH. Imaging characteristics were analyzed and the differential diagnoses assessed in a masked fashion by two experienced radiologists. Results. Typical X-ray features included aggressive, destructive tumor growth centrally located in the metaphysis of long bones. Periosteal reactions and expansive growth were rarely seen. On MR images extraosseous tumor spread was frequently noted. On T2-weighted images and contrast-enhanced T1-weighted images most of the tumors displayed an inhomogeneous, nodular signal pattern with peripheral Gd-DTPA enhancement. Conclusions. Although several MR imaging criteria were typical for MFH none of them was specific. X-ray diagnosis of MFH may also prove difficult, with the main differential diagnosis being metastasis in the older and osteosarcoma in the younger population.     

Angiomyolipoma arising in the thigh

A 41-year-old man presented with an asymptomatic mass in the right medial thigh. Magnetic resonance imaging (MRI) revealed a well-demarcated, 10-cm mass in the right adductor muscles. The margins of the mass exhibited high signal intensity and the rest showed low or iso signal intensity on T1-weighted MR images. However, the high signal intensity was decreased on T2-weighted images with fat suppression. The central part of the tumor was of inhomogeneous high signal intensity on T2-weighted images; after Gd-DTPA injection it enhanced inhomogeneously on T1-weighted images with fat suppression. On dynamic computed tomography (CT) in the arterial phase, there were strongly enhancing spotty areas in the tumor. At surgery, a yellow-whitish tumor was resected and a pathological diagnosis of angiomyolipoma (AML) in the thigh was made. Received: 21 June 1999 Revision requested: 28 July 1999 Revision received: 13 December 1999 Accepted: 15 December 1999     

Magnetic resonance imaging of cartilaginous tumors: a retrospective study of 79 patients

Objective: Hyaline cartilaginous tumors are characterized by extremely high signal intensity on T2-weighted images. Recently, some distinctive MR features of cartilaginous bone tumors were reported in small series. Low signal intensity septa surrounding high signal intensity cartilage lobules were seen on T2-weighted images in low-grade chondrosarcomas. On spin-echo T1-weighted images after Gd contrast injection, marked ‘septal’ or ‘ring-and-arc’ enhancement was observed in low-grade chondrosarcomas and enchondromas. The purpose of this study was to determine sensitivity and specificity of these MR findings in diagnosis of cartilaginous tumors, and to assess the value of MR in diagnostic workup of these lesions. Materials and methods: Retrospective evaluation of MR findings in 79 cartilaginous tumors and in 79 non-cartilaginous tumors. All lesions were biopsy proven. Each MR examination was independently reviewed by two experienced radiologists without knowledge of clinical data, radiographic and/or CT findings, or histological diagnosis. All lesions were evaluated for morphology (lobular or non-lobular), presence of a high signal intensity mass on T2-weighted images, presence of low signal intensity septa separating high signal intensity lobules on T2-weighted images, and evidence of septal (‘ring-and-arc’) enhancement.Results: None of the reviewed parameters is useful in diagnosing osteochondromas. Since osteochondromas have a characteristic appearance on plain radiography, the value of MR imaging in the workup of these lesions remains limited. MR findings in enchondromas have a low specificity and a low sensitivity. Low-grade chondrosarcomas, often hard to diagnose on plain radiography and difficult to differentiate from enchondromas, are characterized by the MR tandem of ‘low signal intensity septa on T2-weighted images’ together with ‘septal or ring-and-arc enhancement’ (sensitivity 92.3%, specificity 76.5%). High-grade chondrosarcomas are easily recognized on plain radiography. Conclusions: In differentiating cartilaginous from non-cartilaginous tumors, MR features are highly specific but lack sensitivity. Grading potentials of MR parameters are promising due to the high accuracy in diagnosing low-grade chondrosarcomas.     

Primary bladder carcinoma: evaluation with MR imaging

Magnetic resonance (MR) imaging was performed in 23 patients (25 tumors) with proved bladder neoplasms. MR studies were retrospectively evaluated and compared with computed tomographic (CT) and pathologic findings. Bladder neoplasms, having a signal intensity intermediate between those of urine and perivesical fat, were best seen on T1-weighted and proton-density images. MR imaging was as accurate as technically well-performed CT studies in detecting extravesical tumor extension. MR could additionally be used to assess the integrity of the bladder wall. On T2-weighted images the normal bladder wall appeared as a thin, linear, low-intensity structure. The disruption of this low-intensity line was indicative of deep muscle invasion, whereas preservation of this low intensity line implied a more localized lesion. Although chemical shift artifacts might cause apparent disruption of the bladder wall, knowledge of this artifact coupled with additional imaging along different planes helps avoid misinterpretation of this artifact as deep muscle invasion.     

Bicipital radial bursitis: CT and MR appearance

The authors present two cases of bicipital radial bursitis in the elbow. In these two cases, different CT and MR imaging patterns were observed. In the first case, postcontrast CT inhomogeneously enhanced the entire lesion. T1-weighted MR images showed the lesion with iso-signal intensity with muscle. T2-weighted images demonstrated the lesion with inhomogeneous high signal intensity, with internal, linear hypointensity. Histologically, the lesion consisted of hypertrophic synovia. In the second case, postcontrast CT failed to enhance the lesion. T2-weighted MR images showed the lesion with homogeneous, marked high signal intensity. Histologically, the lesion consisted of a monocystic bursa lined by thin synovial lining layers.     

Nodular fasciitis: correlation of MRI findings and histopathology

OBJECTIVE: To compare the histopathology of nodular fasciitis (NF) with the magnetic resonance imaging (MRI) findings in order to evaluate the basis of the MR signal characteristics. DESIGN AND PATIENTS: Ten patients with NF, nine females and 1 male, with an age ranging from 13 to 58 years (mean 26.8 years) were studied. MRI findings, available in all 10 patients, were compared with the histopathology in nine patients, and an area-to-area comparative study of the whole specimen section histopathology and MRI was performed in two patients. RESULTS: On the basis of an excisional biopsy or resection specimen, the nine lesions were classified into myxoid ( n=4), cellular ( n=3) and fibrous ( n=2) subtypes. Four myxoid lesions with a subcutaneous location showed a homogeneous SI comparable with muscle on T1-weighted images, high SI on T2-weighted images, and had homogeneous enhancement. One cellular lesion presented with homogeneous, slightly higher SI than muscle on T1-weighted images and inhomogeneous, high SI on T2-weighted images. Alcian blue stain of the whole specimen section revealed the lesion had two parts corresponding to different enhancement patterns on MRI. The blue-stained myxoid part showed markedly diffuse enhancement, while the non-stained cystic space had only peripheral enhancement. Two other cellular lesions had the same appearance on both T1- and T2-weighted images and showed inhomogeneous, diffuse enhancement. One fibrous subtype lesion presented with inhomogeneous, overall slightly higher SI than muscle on T1-weighted images, lower SI at the periphery and high SI in the center on STIR images and only peripheral enhancement. Microscopy and CD-31 staining of the lesion showed more extracellular matrix, with poor vascularity in the center and more collagenous matrix with higher vascularity at the periphery. CONCLUSION: Although similar findings were found in some lesions, the large histologic variability of NF hampers the definition of a prototype of NF on MRI. However, the MRI appearance of the myxoid subtype is rather characteristic. Histologic findings reflect the different SI characteristics and enhancement pattern on MRI.     

原发性骨骼恶性纤维组织细胞瘤影像表现与病理对照研究

目的 分析原发性骨骼恶性纤维组织细胞瘤(MFH)影像表现与病理的关系,以提高诊断准确性.方法 回顾性分析经手术病理证实的原发性骨骼MFH 13例,术前分别经X线平片、CT平扫、MR SE T1 WI、T2 WI和增强T1 WI检查,复习影像表现并与手术病理作对照.结果 13例原发骨骼MFH中,11例位于骨端,2例位于骨干,位于骨端者与骨性关节面的距离为1～5 cm.肿瘤呈溶骨性骨质破坏,直径5.3～12.7 cm.其中,破坏区偏心10例,破坏区内见少许分隔7例,周边不连续硬化11例,伪足样突起7例,骨膜增生2例,软组织肿块9例,所有患者软组织肿块体积较小.CT扫描显示肿瘤密度与肌肉密度相仿.在MR T1 WI肿瘤为等低信号,在T2 WI为混杂信号,T2 WI常见片状等低信号,病灶周围常见不完整的低信号环,环外见伪足样突起.动态增强呈进行性延迟强化,强化显著,且较均匀.大体病理显示病灶偏心,膨胀不明显,肿瘤多突破皮质形成范围较小的软组织肿块,呈结节状或假性包裹样,肿瘤内见纺锤形成纤维细胞和胞体较小的组织细胞样细胞,伴有数量不等的胶原纤维,细胞密集呈席纹状或放射状排列.肿瘤微血管丰富.结论 原发骨骼MFH好发于中年患者长骨骨端,T2 WI常见等低信号成分,增强扫描强化显著;MRI表现与病理关系密切.     

Neuroendocrine tumors of the pancreas: spectrum of appearances on MRI

We reviewed our 8.5 year experience with magnetic resonance imaging (MRI) in the demonstration of neuroendocrine tumors of the pancreas using precontrast fat-suppressed T1-weighted, fat-suppressed T2-weighted, and serial post-gadolinium T1-weighted images, to describe the spectrum of appearances of these tumors. All MR examinations of patients with histologically proven neuroendocrine tumors were retrospectively reviewed. Histological type, tumor location, tumor diameter, signal intensity on precontrast images, enhancement patterns, and presence and appearance of metastases were determined. Twenty-two patients had histologically proved neuroendocrine tumors detected by MRI over the 8.5 year period. Histological types were gastrinoma (n = 8), insulinoma (n = 3), glucagonoma (n = 2), somatostatinoma (n = 1), VIPoma (n = 1), ACTHoma (n = 1), carcinoid (n = 1), and five untyped tumors. Primary tumors ranged in diameter from 1 to 6.2 cm. There was one histopathology-proven false-positive neuroendocrine tumor. The positive predictive value for MRI in the detection of these tumors was 96%. The most common appearance on precontrast images was low signal intensity on T1-weighted images and high signal intensity on T2-weighted images, which was observed in tumors in 18 of 22 patients. Moderate or intense early enhancement of all or portions of the primary tumors was observed in tumors in 19 of 22 patients either as uniform homogeneous, ring, or diffuse heterogeneous enhancement. Enhancement was minimal on these images in the other three patients. Gastrinomas enhanced in a ring pattern in 7 of 8 patients whereas the majority (9 of 11 patients) of noninsulinoma-nongastrinoma and untyped tumors enhanced in a diffuse heterogeneous fashion. Liver metastases were present in 13/22 patients including 3/8 with gastrinoma and 9/11 with noninsulinoma-nongastrinoma tumors. Most neuroendocrine tumors of the pancreas are low signal intensity on fat-suppressed T1-weighted images and moderately high in signal intensity on fat-suppressed T2-weighted images, although variations do exist. Tumors most often enhance in an early moderately intense fashion. Gastrinomas are often different in appearance than other neuroendocrine tumors in that they usually enhance in a ring fashion whereas nongastrinoma-noninsulinoma tumors usually enhance in a heterogeneous fashion.     

CT and MR imaging of advanced Zollinger-Ellison syndrome

The CT and magnetic resonance (MR) findings in 13 patients with advanced Zollinger-Ellison syndrome are described. In eight patients (62%) one or more primary tumors were found with both methods. All patients with proven liver metastases (n = 7) were identified by MR. Computed tomography was positive in six of these patients. Three patients with lymph node metastases were identified on CT and MR and one patient had bone metastases. Computed tomography and MR were inferior to selective arteriography in the detection of multiple lesions of the pancreas in a patient with multiple endocrine neoplasia-I syndrome. On the T1-weighted MR images, the primary tumors demonstrated no consistency with regard to their signal intensity relative to the adjacent pancreatic parenchyma. All gastrinomas had an increased relative signal intensity on the T2-weighted images with the exception of a calcified tumor. Liver and lymph node metastases had a low signal intensity on the T1-weighted images and an increased signal intensity on the T2-weighted images. The signal intensity of primary tumors and metastases was independent of size. In conclusion, MR was able to detect abnormalities based on its outstanding lesion/normal tissue contrast, whereas CT diagnosis was based mostly on contour distortion. For the current technique, MR is considered at least equal to CT.