Marked Contrast Enhancement Research Articles

Intracranial Inflammatory Pseudotumors: MRI and CT Findings

Purpose : The purpose of this study was to describe the MR imaging and CT findings of intracranial inflammatory pseudotumors.Materials and Methods : We reviewed the MR imaging (n=8) and CT (n=4) studies of eight patients (M:F =4:4, mean age: 41 years) with pathologically proven intracranial inflammatory pseudotumor. The findings were then evaluated with regard to location, shape, MR signal intensity, CT density and degree of contrast enhancement of the lesion, surrounding parenchymal edema, adjacent bone change and the location of accompanying extracranial lesion.Results : In two patients, the parietal convexity was involved unilaterally, with no extracranial mass, and in the other six, the middle cranial fossa was involved unilaterally and extracranial mass was present. The lesion also involved the tentorium in four cases, the cavernous sinus in four, the anterior cranial fossa in one, and the posterior cranial fossa in one. The location of extracranial mass was the mastoid and middle ear cavity in two cases, the infratemporal fossa in two, both the infratemporal fossa and paranasal sinuses in one, and the orbit in one. MR images showed diffuse dural thickening in all eight cases, leptomeningeal thickening in four, and focal meningeal-based mass in two. As seen on T1 weighted images, the lesions were isointense to gray matter in eight cases, and on T2-weighted images were hypointense in seven cases and isointense in one. Marked homogeneous contrast enhancement was seen in all eight cases. The lesions seen on brain CT, performed in two cases, were isodense. Adjacent brain parenchymal edema and the destruction of adjacent bones were each seen in five cases.Conclusion : The characteristic MR findings of intracranial inflammatory pseudotumors are(1) diffuse dural thickening;(2) a focal meningeal-based mass which on T2-weighted images is seen as hypointense; and marked (3) contrast enhancement : these findings are, however, nonspecific. In order to differentiate these tumors, an awareness of these findings is, however, useful.

Paraganglioma in the nasal cavity

Paragangliomas, uncommon tumors in the head and neck region, are especially rare in the nasal cavity. The authors have experienced a case of nonchromaffin paraganglioma in the nasal cavity. To our knowledge, this case report is the 3rd in Japan and there have been seventeen reported cases in the literature. The patient, a 16-year-old man, had complained of left recurrent epistaxis since December 1994 and was referred to our hospital in May 1995. On physical examination, a polyp-like mass was noted on the anterior surface of the left middle turbinate.The mass had a rich capillary network and tended to bleed easily. Paranasal sinuses x-rays were normal, except a tumor-like shadow found in the left nasal cavity. Computed tomography demonstrated a small mass in the left nasal cavity and marked contrast enhancement. After external carotid angiography and embolization, a surgical operation was done. Histopathological diagnosis of paraganglioma was made because of the typical finding of “Zellballen” pattern.Paraganglioma is a benign tumor but has the potential of local recurrence, lymph node metastasis and distant metastasis, so it requires a long-term follow-up.

Morphology and staging of primary mucosa-associated gastric lymphoma in hydro-CT imaging

Evaluation by hydro-CT in diagnosing and staging of primary non-Hodgkin lymphoma of the stomach (MALT). 15 patients with MALT lymphoma underwent imaging by hydro-CT (helical CT scanning optimised for parenchymal and vessel contrast with distension of the gastric wall by water). The CT scans were evaluated for the site, morphology, extent and contrast enhancement of gastric lymphoma; in addition, the number and location of abdominal lymph nodes were examined. The results of CT imaging were compared with the findings at endoscopy + biopsy and endosonography and in case of gastrectomy also with the histopathological results. All lymphomas were correctly diagnosed and were mostly located in the distal parts of the stomach. MALT lymphoma typically grew submucosally, infiltration of the mucosa was rare. Most tumours showed marked contrast enhancement of the mucosa and poor enhancement of the submucosa. Hydro-CT and endosonography had similar accuracies in respect of staging of compartment I and II lymph nodes. Staging of distant nodal groups was more accurate by hydro-CT. Hydro-CT is non-invasive and may be used for diagnosis and staging of primary gastric lymphoma with a typical morphology of gastric lymphoma. Hydro-CT may be regarded as complementary to endosonography and is well suited for the initial diagnosis of gastric lymphoma as well as for the diagnosis of recurrent tumour.

Esiste impregnazione contrastografica nell'encefalopatia di Wernicke in fase acuta? Descrizione di 3 casi e revisione della letteratura

MR imaging enabled diagnosis of Wernicke's encephalopathy by showing symmetric areas of increased signal intensity on proton density and T2 weighted images in the periaqueductal gray matter, mammillary bodies, medial thalami and pericentral and interhemispheric cerebral cortex in three non-alcoholic patients who were examined within 3 days of admission for acute confusional state associated with ophthalmoparesis and ataxia. In two patients the initial examination was completed with intravenous contrast administration and no lesion enhancement was seen. In the third patient computed tomography 10 days after the initial MR imaging study showed marked contrast enhancement of the lesions. Our data and a review of the literature indicate that lesion contrast enhancement presumably reflecting disruption of the blood brain barrier may be lacking in the early phases of Wernicke's encephalopathy. Acquisition and careful evaluation of long TR images is crucial to the diagnosis of Wernickes encephalopathy with MR imaging in the acute phase.

Peripheral cholangiocarcinoma of the liver: two-phase spiral CT findings.

To determine characteristic features of peripheral cholangiocarcinoma on two-phase spiral computed tomographic (CT) scans. Thirty-four patients with peripheral cholangiocarcinoma underwent two-phase spiral CT. Hepatic arterial phase and portal venous phase images were obtained 30 and 65 seconds, respectively, after the start of contrast material infusion. Thin, mild, incomplete rimlike contrast enhancement at the tumor periphery was seen on CT scans from both phases in 23 patients. Thick, continuous rimlike contrast enhancement and marked homogeneous contrast enhancement were present on scans in four patients and one patient, respectively. No definite contrast enhancement pattern was seen on scans in six patients. Other findings included increased lobar or segmental hepatic attenuation in adjacent normal liver during the arterial phase (n = 10), markedly low attenuation with amorphous areas of slightly high attenuation in the tumor during both phases (n = 33), internal septumlike linear structures (n = 8), narrowing or obstruction of the portal vein as it traversed the tumor (n = 16), and a patent hepatic vein (n = 4). Thin, mild, incomplete rimlike contrast enhancement at the tumor periphery and markedly low intratumoral attenuation with amorphous areas of slightly high attenuation during both scanning phases are typical findings of peripheral cholangiocarcinoma.

Struma Ovarii: MR Findings

The purpose of this study was to determine the MR appearance of struma ovarii correlating with the pathological features. MR findings of two patients with struma ovarii were retrospectively reviewed and compared with the pathological findings. Both tumors were complex masses composed of multiple cysts and solid components. The size and signal intensity of multiple cysts varied within the tumor. Hyperintense cystic areas on T1-weighted images were thought to correspond pathologically to hemorrhagic cysts and follicles containing viscous proteinaceous colloid. Solid components had as high a signal intensity as did uterine endometrium on T2-weighted images and as intermediate a signal intensity as did uterine muscle layer on T1-weighted images. After intravenous administration of gadolinium-DTPA, the solid components showed marked contrast enhancement. There was also ascitic fluid associated with adhesion and peritoneal thickening. The characteristic MR appearance of struma ovarii is thought to be a mixed mass composed of T2-hyperintense solid components with intense contrast enhancement and multiple T1-hyperintense cystic areas suggestive of hemorrhagic degeneration and viscous proteinaceous colloid.

Bilateral ocular myositis with severe bilateral optic neuropathy

A 48-year-old man developed bilateral orbital myositis with almost complete loss of vision in both eyes from optic neuropathy. Computerized tomographic scans revealed marked contrast enhancement of extraocular muscles. It is assumed that physical compression due to enlarged extraocular muscles as well as adjacent inflammatory infiltration at the orbital apex caused optic neuropathy. Treatment with 200 mg of prednisolone for 2 days followed by oral taper dramatically improved eye movement restriction and visual disturbance.

LOW FIELD MAGNETIC RESONANCE IMAGING CHARACTERISTICS OF CRANIAL VAULT MENINGIOMAS IN 13 DOGS

Meningiomas are common intracranial masses in the dog, and surgical or radiation treatment of meningiomas depends on accurate identification and location. In this review of 13 patients with confirmed meningioma, low field magnetic resonance imaging characteristics of cranial vault meningiomas included increased signal intensity on T2‐weighted images, decreased signal intensity on T1‐weighted images, and marked contrast enhancement that was usually nonhomogeneous and well‐defined. Mass effect and edema were usually present. Cyst formation and meningeal enhancement were also found in some patients. Low field magnetic resonance imaging characteristics of the meningiomas in these patients were similar to those magnetic resonance imaging findings reported in humans and the few reports pertaining to animals.

Meningiomas arising from the falcotentorial junction. Clinical features, neuroimaging studies, and surgical treatment.

Meningiomas arising from the falcotentorial junction are extremely rare. The authors describe the clinical features, neuroimaging studies, and results of surgical treatment of meningiomas of the falcotentorial junction and clarify the characteristics of this lesion based on a review of the literature and seven patients treated at their institution. The most common symptoms resulted from intracranial hypertension. Upward-gaze palsy appeared in only one patient. Computerized tomography (CT) showed no specific findings, but there was no evidence of edema around the tumor. Magnetic resonance (MR) imaging revealed a round, smooth-bordered mass with a peritumoral rim, without edema, and showing marked contrast enhancement. The multiplanar capability of MR imaging delineated the relationship between the tumor and adjacent structures better than did CT. Detailed knowledge of the vascular structures, especially evidence of occlusion of the galenic venous system and the development of collateral venous channels, is critical for successful surgery; stereoscopic cerebral angiography is necessary to achieve this aim. The seven patients described developed five types of collateral venous channels: through the basal vein of Rosenthal to the petrosal vein, through the veins on the medial surface of the parietal and occipital lobes to the superior sagittal sinus, through superficial anastomotic veins, through veins of the posterior fossa to the transverse or straight sinus, and through the falcian veins to the superior sagittal sinus. The first three types mainly developed after occlusion of the galenic system. The tumors were removed through the occipital transtentorial approach with a large window at the posterior part of the falx. A favorable prognosis for patients undergoing surgical treatment of falcotentorial junction meningiomas can be expected if detailed neuroimaging studies and microsurgical techniques are used.

Hepatocellular carcinoma diagnosed radiologically, treated by transcatheter arterial embolization and limited-field radiotherapy

I was disappointed to read the case report by Le Pechoux et al [1] describing the radiological diagnosis of a hepatocellular carcinoma treated by transcatheter arterial embolization and limited-field radiotherapy. That the authors should have submitted this paper is bad enough, but for a reputable British journal to have accepted it is inexcusable. It is well known by radiologists that the majority of solitary hepatic tumours cannot be reliably diagnosed by radiological means alone and biopsy is mandatory in most patients. There are very few exceptions to this rule. The tumour described by the authors of this paper is large and has a very well defined border. On computed tomography (CT) it shows early and marked contrast enhancement to a greater degree than normal hepatic parenchyma.

Characteristic findings of adenoid cystic carcinoma on MR imaging and differentiation from squamous cell carcinoma

Ten patients with adenoid cystic carcinoma and 49 with squamous cell carcinoma confirmed by aiopsy were evaluated. In these patients, malignant tumors were suspected with clinical progressions and clinical symptoms. The purpose of this study was to analyze and discuss the characteristic findings on MR imaging of adenoid cystic carcinoma in the head and neck, and to examine the usefulness of MR imaging in the differentiation between adenoid cystic carcinoma and squamous cell carcinoma. The characteristics on MR imaging of adenoid cystic carcinoma are a high signal intensity on T2-weighted images, marked enhancement by Gd-DTPA, and a capsular structure. All cases of recurrent adenoid cystic carcinomas also showed upward extension. We consider that the high signal intensity on T2-weighted images, the marked contrast enhancement and the capsular structure in MR imaging can be useful in differentiating adenoid cystic carcinoma and squamous cell carcinoma.

MRI monitoring of experimental cerebral ischaemia: comparison of two models

In experimental stroke research one of the key questions is whether animals models truly reflect human disease. One important reason for modelling stroke is to produce tissue changes that can be used to validate the correlation between the results of advanced radiological imaging and pathology. The aim of this study was to compare two minimally invasive rat models of focal ischaemic stroke as to their ability to simulate clinical stroke reproducibly. In one model a focal infarct was induced using the photochemical Rose Bengal technique. The second model was based on transvascular occlusion of the middle cerebral artery using a cervical approach. In all animals we performed MRI at different times with two different paramagnetic contrast agents. The time course of blood-brain-barrier disruption in the Rose Bengal model differed entirely from that in human brain ischaemia. The experimental stroke showed marked contrast enhancement in the first hour after the onset of ischaemia. On the other hand, the MRI changes in the suture occlusion model were very similar to the changes observed in human brain ischaemia: no early disruption of the blood-brain-barrier and increased T2-signal 4-6 h after the onset of stroke. We hope that the suture occlusion model will be used for research not only by basic and clinical scientists but also by radiologists, who, using modern imaging methods, may greatly influence the diagnosis as well as the management of this devastating disease.

Sclerosing hemangiomas of the lung and interlobar fissures: CT findings.

Sclerosing hemangioma is a rare pulmonary tumor. This article describes CT features of the tumor on the basis of CT-pathology correlation. The CT features of eight patients with sclerosing hemangioma of the lung were studied retrospectively and were correlated with the pathologic findings of the resected specimens. All eight patients had an incidental lung mass found on chest radiographs. Seven patients were female. Contrast enhancement of the masses was assessed visually by two radiologists independently, and the density was measured before and after contrast enhancement by using a standard cursor in three patients. On CT, sclerosing hemangiomas appeared as well defined juxtapleural masses in all cases. The tumors enhanced by visual criteria in all but one patient with the smallest mass. The CT density of the enhancing mass ranged from 96 to 157 HU. Three patients had calcification and two had well defined areas of low attenuation. On CT-pathology correlation, the higher, iso-, and lower attenuation areas corresponded with angiomatous, solid and sclerotic, and cystic areas, respectively. A well defined juxtapleural mass with marked contrast enhancement coupled in select cases with foci of sharply marginated areas of low attenuation and calcification are characteristic CT findings of sclerosing hemangioma and should suggest this diagnosis especially in women with these findings.

MR imaging of eosinophilic granuloma: report of 11 cases.

The findings in 11 patients with histologically proven eosinophilic granuloma (EG) examined by magnetic resonance imaging (MRI) are described. In contrast with the variable appearance of EG on conventional radiography and computed tomography (CT), relatively constant features--intermediate to high signal intensity on T1-weighting, high signal intensity on T2-weighting, marked enhancement--were found on MRI. MRI was superior to other imaging methods in demonstrating bone marrow involvement and any accompanying soft tissue mass or inflammation. Intermediate to high signal intensity on T1-weighting and marked contrast enhancement could not be "explained" by histological findings. Prediction of the evolutionary phase of EG by MRI remains questionable because of the phase I (proliferative) histology of all 11 lesions.

Radiological presentations of Castleman's disease

The radiographic appearances of three cases of Castleman's disease of hyaline vascular type are reported. CT demonstrated homogeneous masses with marked contrast enhancement. Calcification was seen in one, and associated lymphadenopathy was seen in two. All tumors were hypervascular with prominent tumor blush on angiography. Sonography showed the masses to be hypoechoic with hyperechoic spots. On MR imaging, all tumors had homogeneous architecture with hypointensity on T1-weighted images and hyperintensity on T2-weighted images. In tumors with above characteristics in areas where lymphoid tissue is normally found, Castleman's disease should be added to the list of differential diagnosis.

Magnetic resonance imaging and histopathology of cerebral gliomas.

The correlation of magnetic resonance imaging (MRI) with histopathological findings was analysed in 26 patients with untreated cerebral gliomas. In low-grade gliomas, T2-weighted images demonstrated relatively homogeneous high-intensity lesions involving both the grey and the white matter. In high-grade gliomas, especially grade IV, T2-weighted images demonstrated prominent heterogeneity in signal intensity, which consisted of a hyperintense "core", less hyperintense or normal intensity "rim" and surrounding finger-like areas of high intensity. Marked and irregular contrast enhancement was evident in all but one case of these high-grade gliomas in which gadolinium-DTPA was used. Histological examination revealed tumour cells extending as far as the borders of the high-intensity areas shown on T2-weighted images in both high- and low-grade gliomas, but in 5 of 8 low-grade and 4 of 18 high-grade gliomas, isolated tumour cells extended beyond the hyperintense areas shown on T2-weighted images.

MR-imaging with Gd-DTPA in carcinomas of tongue, oro- and hypopharynx

High-field MRI was performed in a series of 24 patients with squamous cell carcinomas of the tongue, oro- and hypopharynx. The value of contrast enhanced T1-weighted images in tumor staging was established prospectively. Non-contrast T1-weighted images did not provide sufficient tumor-delineation. Marked contrast enhancement produced by Gd-DTPA was observed in all carcinomas and in normal pharyngeal mucosa. In tumors of the tongue and upper pharynx clinical examination and ultrasound were equally sensitive as post-contrast MRI; in tumors of the lower pharynx the true tumor extension could be better assessed by contrast-enhanced MRI.

Small hepatocellular carcinoma and cavernous hemangioma: differentiation with dynamic FLASH MR imaging with Gd-DTPA.

Forty patients with hepatocellular carcinoma (HCC) (n = 22) or cavernous hemangioma (diameter, 3 cm or less) (n = 18) were examined with serial magnetic resonance (MR) imaging at 1.5 T with the fast low-angle shot (FLASH) technique and an intravenously administered bolus injection of 0.05 mmol/kg Gd-DTPA. Two images per minute were obtained for 5 minutes, and one per minute thereafter until about 10 minutes. Dynamic MR studies revealed five criteria for differentiating these tumors. With HCC there was a hyperintense mass before contrast material enhancement (32%), peak contrast enhancement at about 10 seconds after injection (55%), slight to moderate peak contrast enhancement (73%), absent or minimal delayed enhancement (100%), and, at morphologic study, a capsule or nodules-in-nodule appearance (59%). With hemangioma there was a hypointense mass before contrast enhancement (72%), peak contrast enhancement more than 2 minutes after injection (72%), marked peak contrast enhancement (83%), moderate to marked delayed enhancement (100%), and, at morphologic study, spreading phenomenon (39%). Seventy-seven percent of HCCs and 83% of hemangiomas satisfied three or more criteria and thus could be differentiated from each other with certainty.

Gliosarcoma with Multiple Extracranial Metastases

A 68-year-old male was hospitalized because of headache, nausea, and disturbance of consciousness. Neurological examination on admission disclosed somnolence, disorientation, marked neck stiffness, papilledema, and quadriparesis. Computed tomography (CT) scanning demonstrated a round mass with marked contrast enhancement in the right sylvian fissure and small contrast-enhanced masses in the interpeduncular, quadrigeminal and ambient cisterns. CT also showed marked peritumoral edema, a midline shift, and hydrocephalus. The patient's consciousness level and respiration deteriorated 3 days after admission and a craniotomy was performed. The tumor, which was well demarcated, firmly attached to the sphenoidal ridge, and grossly appeared to be a meningioma, was totally removed. Histologically, the tumor had two well defined components, glioblastoma and fibrosarcoma. The patient underwent ventriculoperitoneal shunting, chemotherapy, and radiotherapy after surgery, but the primary tumor soon recurred, with scalp metastasis, and he died 5 months postoperatively. Autopsy revealed metastases to the liver, spleen, and spinal cord. The histogenesis of this mixed tumor and the mechanism of extracranial metastasis are discussed, and the literature is reviewed.

The utility of contrast media in MRI at 0.02 T. A preliminary report.

The effect of 0.1 mmol gadolinium-DTPA on ultralow field magnetic resonance (MR) images of intracranial neoplasms was studied on 20 patients. Tumors that characteristically were enhanced markedly on computed tomography (CT) (meningiomas, acoustic neuromas) demonstrated moderate to marked contrast enhancement with inversion recovery sequences and with saturation recovery sequences with a short repetition time. Standard spin-echo sequences failed to show any contrast effect. The enhancement of gliomas and metastases was weak and often absent. Contrast enhancement, when present, was helpful in delineating the tumor from surrounding edema but the differentiation of living from necrotic tumor was not successful because of low signal intensity. The low effect of gadolinium-DTPA at 0.02 T may be due to a relatively higher T2 weighting of available pulse sequences. The relaxing effect of macromolecules may also change the proportional effect of paramagnetic substances in an ultralow magnetic field.