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Purpose: Sampling perfection with application-optimized contrasts by using different flip angle evolutions (SPACE) is a black-blood 3D T1-weighted (T1w) magnetic resonance imaging (MRI) sequence that has shown robust performance for brain metastases detection. However, this could generate false positive results due to suboptimal blood signal suppression. For that reason, SPACE is used in our institution alongside a non-black-blood T1w sequence: volumetric interpolated breath-hold examination (VIBE). Our study aims to (i) evaluate the diagnostic accuracy of SPACE compared to its use in combination with VIBE, (ii) investigate the effect of radiologist's experience in the sequence's performance, and (iii) analyze causes of discordants results. Methods: Four hundred seventy-three 3T MRI scans were retrospectively analyzed following a monocentric study design. Two studies were formed: one including SPACE alone and one combining both sequences (SPACE + VIBE, the reference). An experienced neuroradiologist and a radiology trainee independently reviewed the images of each study and reported the number of brain metastases. The sensitivity (Se) and specificity (Sp) of SPACE compared to SPACE + VIBE in metastases detection were reported. Diagnostic accuracy of SPACE compared to SPACE + VIBE was assessed by using McNemar's test. Significance was set at p < 0.05. Cohen's kappa was used for inter-method and inter-observer variability. Results: No significant difference was found between the two methods, with SPACE having a Se > 93% and a Sp > 87%. No effect of readers' experience was disclosed. Conclusion: Independently of radiologist's experience, SPACE alone is robust enough to replace SPACE + VIBE for brain metastases detection. [ABSTRACT FROM AUTHOR]

Purpose: Although contrast-enhanced three-dimensional T2 fluid-attenuated inversion recovery (3D T2-FLAIR) images are useful for assessing various neuronal diseases, physiological enhancement of the circumventricular organs on the images have not been investigated. We aimed to assess the physiological appearance of the circumventricular organs on contrast-enhanced 3D T2-FLAIR images.Methods: We studied 3-T MR images of the brain of 30 individuals with no apparent brain abnormalities. In ten areas of the brain, the degree of contrast enhancement on 3D T2-FLAIR and magnetization-prepared rapid gradient-echo (MPRAGE) images was evaluated using a 4-point grading system. The pre- and post-contrast mean contrast ratios (CRs) of the anterior pituitary gland, median eminence, and pineal gland were compared.Results: On post-contrast 3D T2-FLAIR images, marked enhancement was most frequently scored in the median eminence, followed by the choroid plexus, posterior pituitary gland, and pineal gland. In 10 of the 30 cases, the vascular organ of the lamina terminalis and the area postrema were enhanced but the subcommissural organ was not. The difference in the mean pre- and post-contrast CRs of the median eminence and pineal gland was statistically significant, while that of the anterior pituitary gland was not.Conclusion: On contrast-enhanced 3D T2-FLAIR images, the circumventricular organs show variable enhancement. Our findings help to recognize physiological and abnormal enhancement of brain structures on contrast-enhanced 3D T2-FLAIR images. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of the study was to evaluate Response Assessment in Neuro-Oncology (RANO) criteria in glioblastoma multiforme (GBM), with respect to the Macdonald criteria and changes in contrast-enhancement (CE) volume. Related variations in relative cerebral blood volume (rCBV) were investigated. Methods: Forty-three patients diagnosed between 2006 and 2010 were included. All underwent surgical resection, followed by temozolomide-based chemoradiation. MR images were retrospectively reviewed. Times to progression (TTPs) according to RANO criteria, Macdonald criteria and increased CE volume (CE-3D) were compared, and the percentage change in the 75th percentile of rCBV (rCBV75) was evaluated. Results: After a median follow-up of 22.7 months, a total of 39 patients had progressed according to RANO criteria, 32 according to CE-3D, and 42 according to Macdonald. Median TTPs were 6.4, 9.3, and 6.6 months, respectively. Overall agreement was 79.07% between RANO and CE-3D and 93.02% between RANO and Macdonald. The mean percentage change in rCBV75 at RANO progression onset was over 73% in 87.5% of patients. Conclusions: In conclusion, our findings suggest that CE-3D criterion is not yet suitable to assess progression in routine clinical practice. Indeed, the accurate threshold is still not well defined. To date, in our opinion, early detection of disease progression by RANO combined with advanced MRI imaging techniques like MRI perfusion and diffusion remains the best way to assess disease progression. Further investigations that would examine the impact of treatment modifications after progression determined by different criteria on overall survival would be of great value. [ABSTRACT FROM AUTHOR]

Introduction: Contrast enhancement observable on magnetic resonance (MR) images reflects the destructive features of malignant gliomas. This study aimed to investigate the relationship between radiologic patterns of tumor enhancement, extent of resection, and prognosis in patients with anaplastic gliomas (AGs). Methods: Clinical data from 268 patients with histologically confirmed AGs were retrospectively analyzed. Contrast enhancement patterns were classified based on preoperative T1-contrast MR images. Univariate and multivariate analyses were performed to evaluate the prognostic value of MR enhancement patterns on progression-free survival (PFS) and overall survival (OS). Results: The pattern of tumor contrast enhancement was associated with the extent of surgical resection in AGs. A gross total resection was more likely to be achieved for AGs with focal enhancement than those with diffuse ( p = 0.001) or ring-like ( p = 0.024) enhancement. Additionally, patients with focal-enhanced AGs had a significantly longer PFS and OS than those with diffuse (log-rank, p = 0.025 and p = 0.031, respectively) or ring-like (log-rank, p = 0.008 and p = 0.011, respectively) enhanced AGs. Furthermore, multivariate analysis identified the pattern of tumor enhancement as a significant predictor of PFS ( p = 0.016, hazard ratio [HR] = 1.485) and OS ( p = 0.030, HR = 1.446). Conclusion: Our results suggested that the contrast enhancement pattern on preoperative MR images was associated with the extent of resection and predictive of survival outcomes in AG patients. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the effect of different volumes of contrast material with and without a saline chaser on tissue enhancement in multidetector row CT (MDCT) of the head and neck. In a blind prospective fashion, 120 patients were randomized into the following four groups: group 1, 80 ml contrast material administered at a flow rate of 2.0 ml/s; group 2, 80 ml followed by 40 ml saline at 2.0 ml/s; group 3, 60 ml at 1.5 ml/s; and group 4, 60 ml followed by 30 ml saline at 1.5 ml/s. The attenuation values of the carotid artery, internal jugular vein, and muscle were measured at an interval of 1.5 s in each patient. The degree of perivenous artifacts was subjectively assessed. Mean attenuation values in the carotid artery and internal jugular vein were significantly higher in groups 1 and 2 than in groups 3 and 4. The width of the diagnostic window (both carotid and jugular enhancement >150 HU) were significantly longer in groups 1 and 2 than in groups 3 and 4. The addition of a saline chaser did not result in improved vascular enhancement or a wider diagnostic window, but reduced perivenous artifacts, compared with using contrast material alone. Reduction of contrast material from 80 to 60 ml results in insufficient enhancement of neck vessels. In addition, the benefit of a saline chaser technique is not obvious except for its ability to reduce perivenous artifacts. [ABSTRACT FROM AUTHOR]

There have been no previous reports on contrast enhancement of the cochlear aqueduct in magnetic resonance imaging. The purpose of the present study was to evaluate the frequency and significance of this finding. Thirty-one patients (15 men and 16 women; age range 18–81 years) with otologic symptoms (sudden sensorineural hearing loss, vertigo, or tinnitus) were examined using contrast-enhanced imaging on a 1.5-T MR scanner. The normal ear served as the control. Two radiologists evaluated contrast enhancement in the area of the cochlear aqueduct. Forty-eight of 62 ears (77.4%) showed contrast enhancement of the cochlear aqueduct, but no significant differences in the frequency of contrast enhancement were observed between patients with and patients without vertigo, tinnitus, sensorineural hearing loss, cerebellopontine angle tumors, or a high-riding jugular bulb. In addition, no gender- or age-related differences were noted. Contrast enhancement of the cochlear aqueduct was frequently observed, but the frequency of enhancement in symptomatic ears was not significantly higher than in control ears. The results of this study may prove helpful in avoiding unnecessary examinations and potential diagnostic confusion. [ABSTRACT FROM AUTHOR]

We report two fatal cases of methotrexate (MTX)-induced disseminated necrotising leukoencephalopathy (DNL) in which MRI was repeated from the onset. Initial T2-weighted images showed multiple areas of high signal, mainly in deep cerebral white matter, which on follow-up, spread and coalesced to involve the entire white matter. Small irregular low-signal foci on T2-weighted images were seen within the high-signal lesions. Multiple areas of contrast enhancement corresponded to these low-signal foci. The condition of both patients deteriorated and they died. We compared their MRI findings with those of seven patients with mild MTX-related leukoencephalopathy, six of whom were asymptomatic; one had transient neurological symptoms. They showed no contrast enhancement, but rather mild-to-moderate diffuse high signal in deep white matter, which later disappeared. These findings suggest that multiple low-signal foci on T2-weighted images with contrast enhancement may be characteristic of DNL, and that contrast-enhanced imaging is useful to differentiate this condition from mild leukoencephalopathy. [ABSTRACT FROM AUTHOR]

Lhermitte–Duclos disease (LDD), also known as dysplastic gangliocytoma, is a rare cerebellar lesion. It has long been regarded as avascular. We report two patients with surgically proven LDD in whom contrast enhancement was observed on MRI. Neuropathological examination revealed proliferation of veins. We suggest that peripheral enhancement of LDD probably reflects vascular proliferation of the cerebellar venous draining system, and should be considered part of the imaging features of LDD. [ABSTRACT FROM AUTHOR]

The frequency, predisposing factors and clinical consequences of haemorrhagic infarcts and damaged blood-brain barrier as shown by contrast enhancement (CE) in ischaemic cerebral infarcts are controversial. We prospectively compared the sensitivity of CT and MRI to haemorrhagic transformation (HT) and CE. We also wished to investigate the clinical significance of HT and factors possibly associated with it. We studied 36 patients with acute ischaemic infarcts in the middle cerebral artery territory during the first 2 weeks after the ictus. After CT and rating of the neurological deficit on admission, serial examinations with clinical neuromonitoring, contrast-enhanced CT and MRI were done on the same day. The occurrence and severity of HT were correlated with CE, stroke mechanism, infarct size, development of neurological deficits and antithrombotic treatment. The frequency of HT detected by MRI was 80 %. CE usually preceded HT or was seen simultaneously. MRI had a higher sensitivity than CT to HT and CE. Severity of HT was positively correlated with infarct size ( P < 0.01). HT had no influence on patient's neurological status. Neither the type of antithrombotic treatment nor the stroke mechanism was associated with the severity of HT. No parenchymal haemorrhage occurred. [ABSTRACT FROM AUTHOR]

Peritumoral edema and contrast enhancement of brain tumors are both thought to be due to breakdown of the blood-brain barrier (BBB); however, the exact mechanism by which these two phenomena occur and whether there is a quantitative or etiological relationship is not known. Our purpose was to determine whether the relationship between the breakdown of the BBB, defined radiologically as the degree of contrast enhancement, and the volume of surrounding edema is different for high-grade gliomas and meningiomas. We analyzed 13 meningiomas and 23 gliomas. A direct linear relationship between the degree of contrast enhancement (dC) and volume of peritumoral edema (V) with a high correlation coefficient ( R = 0.66, P = 0.0006) was established for gliomas. A mathematical relationship between dC and V could not be established for meningioma. The findings for gliomas offer indirect radiological evidence that the defect in the BBB which causes edema is quantitatively and etiologically related to the defect in the BBB responsible for contrast enhancement. For meningiomas, the lack of a relationship between dC and V implies either that the mechanisms responsible for formation of edema and contrast enhancement are fundamentally different or that a physical barrier in certain meningiomas limits propagation of edema into the adjacent white matter. [ABSTRACT FROM AUTHOR]

We compared contrast enhancement on T1-weighted MRI of acute cerebral infarcts after conventional bolus administration and continuous infusion of gadolinium. We examined 12 patients with a history of acute stroke with contrast-enhanced MRI once a week for a 1 month. Only ischaemic lesions were investigated after cerebral haemorrhage had been excluded by CT. Each MRI study included T2- and proton density-weighted sequences for determination of the size and site of the infarct, immediate postinjection T1-weighted imaging after bolus administration of 0.1 mmol/kg gadolinium-DPTA and delayed T1-weighted imaging after additional continuous infusion of 0.1 mmol/kg over 2 h. A total of 42 MRI studies was performed. In the first week after the onset of stroke, most infarcts (8 of 10) did not enhance after bolus administration, whereas all showed distinct contrast enhancement after the infusion. In the following weeks all but two infarcts showed contrast enhancement after bolus administration; after continuous infusion contrast enhancement could be seen in all cases. While contrast enhancement after bolus administration showed the typical gyriform pattern, enhanced areas were more extensive after the infusion and usually covered the entire infarcted area shown on T2- and proton density-weighted images. We presume that the disturbed blood-brain barrier in ischaemic areas favours delivery of contrast medium to the infarcted tissue if it is offered continuously so that a steady state can develop. [ABSTRACT FROM AUTHOR]

The clinical significance of preoperative gadolinium DPTA enhancement around disc herniations and in the epidural space on MRI is not clear. The relation of nerve root enhancement to dysfunction also remains controversial. To investigate the clinical significance of contrast enhancement we looked at the symptoms and signs and gadolinium DPTA-enhanced images of 71 consecutive surgical candidates in a standardised fashion. Annular rupture and disc enhancement were found to be closely related, and correlated with sensory loss and paresis, respectively. Nerve root enhancement was found to be related to neurological deficits in general and sensory impairment in particular. [ABSTRACT FROM AUTHOR]

Our purpose was to compare prospectively the sensitivity of contrast-enhanced magnetisation transfer (MT) MRI and gradient-echo (GE) T1-weighted images in metastatic disease of the brain. We studied 52 patients with brain metastases, using conventional T1-weighted GE and MT spin-echo (SE) images after the same standard dose of gadolinium. Axial 5-mm reconstructions of GE data were compared with 5-mm MT images in the same plane. Metastases were counted independently by two neuroradiologists. In 12 patients (23 %) MT imaging showed more metastases than GE images ( P = 0.03). We detected 68 more metastases with the former technique. [ABSTRACT FROM AUTHOR]

To examine the chronological changes characteristic of cortical laminar necrosis caused by brain infarction, 16 patients were repeatedly examined using T1-, T2-weighted spin-echo, T2*-weighted gradient echo, fluid attenuated inversion recovery (FLAIR) images, and contrast enhanced T1-weighted images at 1.0 or 1.5 T. High intensity cortical lesions were visible on the T1-weighted images from 2 weeks after ictus and became prominent at 1 to 3 months, then became less apparent, but occasionally remained at high intensity for 2 years. High intensity cortical lesions on FLAIR images became prominent from 1 month, and then became less prominent from 1 year, but occasionally remained at high intensity for 2 years. Subcortical lesions did not display high intensity on T1-weighted images at any stage. On FLAIR images, subcortical lesions initially showed slightly high intensity and then low intensity from 6 months due to encephalomalacia. Cortical lesions showed prominent contrast enhancement from 2 weeks to 3 months, but subcortical lesions were prominent from 2 weeks only up to 1 month. T2*-weighted images disclosed haemosiderin in 3 of 7 patients, but there was no correlation with cortical short T1 lesions. Cortical laminar necrosis showed characteristic chronological signal changes on T1-weighted images and FLAIR images. Cortical short T1 lesions were found not to be caused by haemorrhagic infarction. [ABSTRACT FROM AUTHOR]

We report two cases of infarcts of the spinal cord with contrast enhancement of the cauda equina on MRI. As enhancement of the infarcted spinal cord waned, that of cauda equina was definite. These appearances suggest disruption of the blood-tissue barrier and possibly hyperaemia of cauda equina following infarcts of the spinal cord. [ABSTRACT FROM AUTHOR]

To assess the potential of registration of images before and after contrast medium for improving the demonstration of contrast enhancement, we compared conventional 2 D T 1-weighted spin-echo images with precisely registered 3 D volume images and subtraction images derived from them in 2 normal subjects and 30 patients with a variety of brain disease. The volume images were registered to subvoxel accuracy using a rigid body translation and rotation, sinc interpolation and a least-squares fit; subtraction images were obtained from these. Normal contrast enhancement was demonstrated better with positionally registered volume and subtraction images than with conventional images in the meninges, ependyma, diploic veins, scalp, skin, orbit and sinuses. Abnormal enhancement was seen better in meningeal disease, multiple sclerosis and tumours as well as on follow-up studies. Subvoxel registration of images before and after contrast medium may be of considerable value in the recognition of contrast enhancement where there are small changes, or where the changes affect tissues with high or low baseline signal values. The technique also appears likely to be of value in demonstrating contrast enhancement in tissues at inferfaces and at other areas of complex anatomy, and in follow-up studies. [ABSTRACT FROM AUTHOR]

The tolerance and diagnostic efficacy of a new nonionic, intravenous MRI contrast medium, gadodiamide injection (Omniscan) are reported and compared with those of gadolinium-DOTA after completion of a double-blind, randomized, parallel study in 60 patients using a dose of 0.1 mmol/kg. Two patients were excluded from the statistical analysis after trial entrance since no contrast medium was injected. The indications for the MRI examination were known or suspected CNS lesions. Vital signs, chemical and haematological parameters were monitored. No significant abnormalities were observed, confirming the excellent tolerance of both contrast media. The usefulness of gadolinium-containing contrast media was again documented, since in 8.6% (5/58) of the patients the lesion(s) could be seen only after injection. Contrast enhancement was seen in 87.8% (43/49) of the patients with abnormal findings, and provided additional diagnostic information in 24.5% (12/49). Lack of contrast enhancement in 12.2% (6/49) of patients with abnormal findings was a significant negative finding. [ABSTRACT FROM AUTHOR]

We studied the signal and enhancement characteristics of the central skull base prospectively in 40 children aged 13 days to 8 years, on a 1.5 T MRI system. Identical standard short TR/TE spin echo sequences in the sagittal plane were performed before and after intravenous gadolinium-DTPA. The sequences used for comparison were filmed at identical window and level settings. Three independent observers assessed (1) the intensity of contrast enhancement of the basisphenoid, basiocciput and presphenoid, (2) the signal intensity of the spheno-occipital synchondrosis, (3) the degree of pneumatization of the sphenoid sinus and (4) the uniformity of signal intensity reflecting fatty replacement of the marrow of the basisphenoid, basiocciput and presphenoid. In 16% and 28% respectively of cases there was no enhancement of the basisphenoid and basiocciput after gadolinium administration; in 42% and 44% there was mild enhancement, and moderate or intense enhancement was observed in 42% and 28% of cases. Even when there was irregular fatty replacement, residual hemopoietic clements could enhance intensely. When skull base neoplasms are being investigated, the normal signal irregularity and enhancement of the central skull base in children must not be confused with pathologic invasion of the marrow. [ABSTRACT FROM AUTHOR]

The authors present seven autopsy cases of non-AIDS primary malignant lymphoma of the central nervous system to correlate the pathology with the findings of the most recent pre-mortem computed tomogram (CT). Of 10 primary contrast-enhancing (CE) lesions treated by chemotherapy alone, radiotherapy alone, radiochemotherapy, or surgery combined with radiochemotherapy, all but one completely disappeared after the initial course of therapy. However, in six of the seven patients, the final pre-mortem CT demonstrated CE lesions. In three cases CE lesions were at the same site as the primary lesion, in one case in a remote location, and in two cases in diffuse and multiple locations. In all but one case these CE lesions corresponded histologically to tumor nodules or to white matter densely infiltrated by tumor cells. The sole exception was diagnosed pathologically as delayed radiation necrosis. The final CT also showed five low-density areas (LDAs) which had evolved from CE lesions after the completion of therapy. These LDAs corresponded to rarefied or necrotic parenchyma in which tumor cells remained, mainly in the perivascular spaces. One case exhibited diffuse tumor infiltration of periventricular structures which appeared to have normal density and no CE on the final pre-mortem CT. [ABSTRACT FROM AUTHOR]

Contrast enhancement has now become an interal part of MR imaging. In this paper, the current uses of contrast agents in MR imaging of both the head and spine are reviewed. In addition, new applications of contrast in MR imaging, including some more current and controversial, are also explored. [ABSTRACT FROM AUTHOR]

The nonionic contrast agent iohexol was compared with the ionic agent iothalamate for contrast enhancement of brain tumors and radiation brain damage in dogs. Tissue enhancement during infusion of contrast and 5, 10, 15 and 30 min later was measured using quantitative computed tomography. Blood iodine was measured using x-ray fluorescence. Peak contrast enhancement occurred during infusion in tumors and after 5 min in irradiated normal brain for both contrast agents. Absolute uptake of contrast in each lesion was the same for both agents when normalized to total grams of iodine administered. Blood iodine levels were slightly but not significantly higher using iohexol. The reduced osmotic load and similar contrast enhancement of lesions suggest that the nonionic contrast medium iohexol may be a useful agent for routine CT of the brain. [ABSTRACT FROM AUTHOR]

Sixty-five patients with recurrent radicular complaints after operation for lumbar disc herniation underwent CT examination before and after intravenous contrast application (volume: 1.5-2.0 ml/kg body weight; flow rate: 0.35 ml/s). Postsurgical hypertrophic scar tissue showed definite contrast enhancement, whereas disc herniation remained unenhanced. Intravenous contrast application is recommended in patients previously operated upon for disc herniation. [ABSTRACT FROM AUTHOR]

Strokes of venous origin are relatively unfrequent. They usually cause venous infarcts which can be observed in 2 main circumstances: cerebral thrombophlebitis or dural arteriovenous (AV) fistulae draining into cerebral veins. The authors study the CT and angiographic aspects of these venous infarcts and their evolution. Conventional angiography remains indispensable to confirm the diagnosis. [ABSTRACT FROM AUTHOR]

The authors report the three principal characteristics of hemispheric ischaemic attacks on CT scan and their development over time: hypodensity, mass effect and contrast enhancement. Their pathophysiological mechanism and prognostic importance are discussed. The topography of the territories of the large arteries vascularising the brain and their main branches is described on the basis of twelve sections cut parallel to the cantho-meatal line. Finally, selcted special aspects are described (misleading aspects, haemorrhagic infarcts, border zone infarcts). [ABSTRACT FROM AUTHOR]

Dynamic computed tomograhic scans were performed in an experimental brain abscess model to establish criteria that could be utilized in abscess staging. The vascular phase of the time-density curves did not differentiate cerebritis and capsule stages. The amount of residual enhancement after the first pass of an intra-arterial contrast bolus differed between major abscess stages, the greater residual enhancement being noted in the capsule stage. [ABSTRACT FROM AUTHOR]

Four types of extradural hematoma could be separated at examination of the plain CT scan in 54 extradural hematomas. Two major groups appear: the still bleeding hematoma showing either generally low attenuation values of 'holes', and a coagulated homogeneous type with generally high attenuation values. The attenuation values of the bleeding-liquid part of hematoma - were correlated to hemoglobin concentration in blood, to which clots were not related. Seven extradural hematomas grew and coagulated on repeated preoperative CT scans. In two cases intravenous contrast was given to the bleeding type of hematoma, and the contrast media appeared in 'holes', but not in areas of high attenuation value. It is easy to distinguish between the different types of hematoma on the plain CT scan, and the separation by eye between the still bleeding and the coagulated extradural hematoma seems reliable. [ABSTRACT FROM AUTHOR]

Pre- and postcontrast scans of the same normal brain tissue layer were compared in 20 patients in order to evaluate postcontrast density response. The original purpose of this investigation was to explain a paradoxical phenomenon of density decrease, which has been regularly observed in our patients. Control phantom measurements revealed that the decrease of density values is a function of the time interval between the analysed and the previous scan. Prolonged interscan interval - due to contrast injection - enables a change in the sensitivity of CT detectors to be registered. It is probable that any study of cerebral blood volume could be unfavourably influenced by this phenomenon. Comparison between the postcontrast brain scan density decrease and density decrease of a phantom showed substantially no difference, so that we estimate the contrast response of the brain parenchyma in toto as insignificant. Further, a comparative analysis between contrast response of the white and gray matter has been made. The gray-white matter difference increased from precontrast 4.56 H to postcontrast 7.82 H. The relatively high difference of 3.26 H between the white and gray matter enhancement compared with negligible enhancement of the brain slice as a whole leads us to the hypothesis, that an absolute decrease of white matter density, as a biological reaction to the injected constrast solution, has to be presumed. [ABSTRACT FROM AUTHOR]

A short term, high dose corticosteroid treatment protocol was investigated to determine its clinical utility in staging an experimental brain abscess. Corticosteroids were shown to decrease the degree of contrast enhancement of brain abscess 12 h after administration but the magnitude of the effect was not consistent enough to be clinically useful in staging. The corticosteroid effect progressively diminished as the inflammatory lesion encapsulated over time. This effect emphasized that a decreasing ring diameter and not diminished contrast enhancement should be the CT criterion for brain abscess resolution. [ABSTRACT FROM AUTHOR]

Information obtained from CT scan after contrast administration was evaluated in 59 consecutive stroke patients. CT scans before and after contrast administration were performed 3 days and 21/2 weeks after stroke. A plain CT scan was repeated 6 months later. Contrast enhancement was practically not seen on the first examination, but was seen in 46% on the second examination. There was a close relationship between the occurrence of contrast enhancement and the socalled 'fogging effect'. Contrast scanning gave additional information only when this effect was present. Plain CT scans 3 days after stroke were superior to contrast scans taken at any time for detecting and visualizing cerebral infarcts. [ABSTRACT FROM AUTHOR]

A study for the evaluation of the reliability of contrast enhanced CT in the differentiation between recurrent disc herniation and hypertrophic scar formation was undertaken. From the retrospective analysis of 36 surgically verified cases it became evident that hypertrophic scar tissue shows definite contrast enhancement, whereas recurrent disc herniation remains unenhanced. A possible explanation for this phenomenon is given. It is concluded that contrast enhancement should be performed in cases being studied by CT for recurrent symptoms after operation for disc herniation. [ABSTRACT FROM AUTHOR]

Analysis of the computed tomograms of 85 purely intrasellar pituitary adenomas documents a highly variable pattern of response to contrast enhancement. Twenty-eight of 85 adenomas exhibited homogeneously increased density. Twenty exhibited heterogeneously increased, patchy or ringlike density; 16, hypodensity; and 8, isodensity with normal pituitary tissue. In 13 patients the predominant CT finding was an empty sella with variable enhancement of the adenoma and residual pituitary tissue. Pathological specimens demonstrated that the hypodense zones observed within pituitary microadenomas may represent pituitary necrosis, cyst, hemorrhage, intratumoral abscess, or relatively less intense enhancement than the normal surrounding pituitary tissue. [ABSTRACT FROM AUTHOR]

The CT findings in a 6-month-old boy with hemophilus influenzae meningitis, complicated by the occurrence of bilateral subdural effusions, are described. The effusions were hypodense and the contents markedly enhanced (increase of 40 Hounsfield units) after contrast injection. [ABSTRACT FROM AUTHOR]

The CT features of intracerebral toruloma are described and the clinicopathological features briefly reviewed. The diagnosis of intracerebral toruloma should be considered when pulmonary opacities are associated with multiple intracerebral enhancing masses. [ABSTRACT FROM AUTHOR]

Using specimens obtained at operation, tissue-blood ratios of iodinated contrast material (iodine), and in some cases also those of red blood cell tracer (Cr), were measured in 23 patients with various kinds of intracranial mass lesions. Results provided confirmatory evidence on the major role played by extravascular iodine in the positive enhancement effect with computed tomography. [ABSTRACT FROM AUTHOR]

Contrast enhancement of malignant gliomas and the development of peritumoral edema are thought to be due to a breakdown of the blood-brain barrier (BBB). The degree to which these two factors are related to each other or to the degree of damage to the BBB is unknown. Our purpose was to quantitatively correlate the degree of enhancement with Gd-DTPA of anaplastic gliomas and glioblastoma multiforme with the volume of surrounding edema. In 14 patients, quantitative measurements of the volume of peritumoral edema and the degree of contrast enhancement were made. A high degree of correlation was found ( r = 0.86, P < 0.01). These results can be viewed as indirect, radiological evidence that edema production is quantitatively related to the degree of breakdown of the BBB as determined by gadolinium enhancement. These results imply that the origin of the edema is in the area of breakdown of the BBB. [ABSTRACT FROM AUTHOR]

The commonly used contrast medium metrizoate (isopaque Cerebral) or the new nonionic iohexol were injected intravenously for enhancement of cranial CT in a randomized double blind study. Each group consisted of 105 patients. No serious reactions occurred. Ten patients receiving metrizoate had minor reactions of mainly allergic type, whereas only one patient receiving iohexol reacted. No differences in enhancement efficiency could be observed. [ABSTRACT FROM AUTHOR]

Five patients with herniated intervertebral disk had undergone a preoperative CT examination with intravenous contrast medium. In 2 cases, intense enhancement was seen around the prolapsed disk. In 1 case, there was an arachnoideal thickening over the herniation, but in the other case, nothing unusual was found around the prolapse at operation. The etiology of the phenomenon is discussed. [ABSTRACT FROM AUTHOR]

A case is described in which an acoustic neuroma appeared on computed tomography as a large cystic lesion. [ABSTRACT FROM AUTHOR]

Contrast enhancement of computerized tomography is usually performed by means of intravenous injection of iodinated contrast materials. The authors have utilized a technique of direct arterial infusion of iodinated contrast material supplying intracranial arteries during computerized axial tomography. A representative case is presented with comparison scans which were obtained without contrast enhancement and with conventional intravenous infusion of contrast. Marked improvement of the enhancement was clearly demonstrated in this case, with abnormalities readily defined that were not seen with the conventional intravenous enhancement procedure. [ABSTRACT FROM AUTHOR]