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At least 73 records · Page 4Linked to original sources

MRI evaluation of the brain in infantile neuronal ceroid-lipofuscinosis. Part 1: Postmortem MRI with histopathologic correlation.

The purpose of this study was to correlate postmortem magnetic resonance imaging (MRI) with histopathologic findings in brains of a series of autopsied patients with infantile neuronal ceroid-lipofuscinosis, a recessively inherited progressive encephalopathy. Eight formalin-fixed brains (age range at death, 7 to 13 years) were examined with MRI. One patient had also undergone brain MRI 2 years before death. Histopathologic analyses were made from standard areas selected on the basis of the MRI scans. Postmortem MRI findings did not differ significantly from the findings in the patient who was also examined during life. Typical findings were extreme cerebral atrophy and hypointensity of the gray-matter structures in relation to the white matter on T2-weighted images, a pattern the reverse of normal. Characteristic histologic findings were almost complete loss of cortical neurons and secondary loss of axons and myelin sheaths in the white matter. The drastically altered relative intensities of the gray- and white-matter structures on the MRI scans reflected replacement of the neurons with hypertrophic astrocytes and/or macrophages filled with storage material.

Brain↗

[MRI in patients with temporal lobe epilepsy: correlation between MRI findings and clinical features].

There have been many X-ray computed tomography (CT) studies on epilepsy in the literature. However, mesial temporal sclerosis, known to form an important pathology of temporal lobe epilepsy, has not been visualized by CT, while magnetic resonance imaging (MRI) has enabled it to be depicted to some extent. Various views exist as to the MRI visualization of mesial temporal sclerosis. Furthermore, only few papers have adequately dealt with clinical features in relation to MRI findings. This study attempted to investigate MRI findings on temporal lobe epilepsy, and then correlate them with clinical variables such as age, duration of illness, past history and seizure frequency. MRI was performed on 45 patients with temporal lobe epilepsy of unknown etiology (24 males and 21 females) with a 0.5 tesla imager and/or a 1.5 tesla imager. Focal abnormalities of signal intensity and dilatation of the inferior horns of lateral ventricles were evaluated on MR images. Six patients had unilateral, mesial temporal high signal areas on T2-weighted images and/or proton density-weighted images at both transverse and coronal views. CT and T1-weighted imaging showed no abnormality in and around the area. These hyperintense mesiotemporal lesions were all in the same side of the epileptogenic focus as shown by electroencephalography. The frequency of partial seizures was significantly higher in these patients than in those without the finding. Three patients had febrile convulsions. It was thought highly likely that this hyperintense area might represent the MRI visualization of mesial temporal sclerosis. Ten patients revealed slight dilatations of the inferior horns of the lateral ventricles. Statistical examinations showed that these patients were also significantly older in age and of later onset. Six patients with unilateral dilatations were significantly younger in age than four with bilateral dilatations. The duration of epilepsy was longer in the latter than in the former. Unilateral dilatation may at least indirectly reflect lesions of the mesial temporal lobe, but bilateral dilatations may be findings related to aging and/or long illness duration. Nine patients had small multiple high signal areas in the white matters of the extratemporal areas, mainly in the parietal lobes. Seizure onsets of these patients were later and the ages were older, which was statistically significant. They did not differ in other clinical features. These high signal areas were probably of vascular origin, not directly related to epilepsy.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗

MRI measurement of hepatocyte toxicity using the new MRI contrast agent manganese dipyridoxal diphosphate, a manganese/pyridoxal 5-phosphate chelate.

This study reports the first in vivo results using an MR contrast agent manganese dipyridoxal diphosphate (Mn-DPDP) designed to estimate the functional status of the hepatocyte. Thirty New Zealand white rabbits were studied in groups of 5 as follows: No. 1, control, MRI scans only; No. 2 MRI before and up to 90 min following 50 mumol/kg of Mn-DPDP iv; No. 3, rabbits received 9.3 g ethanol/kg and MRI; No. 4, as in No. 3 but following Mn-DPDP; No. 5, MRI as in No. 2 but 18 h. following 1000 mg/kg D-galactosamine used to induce hepatocyte necrosis; and No. 6, rabbits received D-galactosamine and MN-DPDP. In this study significant ethanol- and D-galactosamine-induced hepatocyte damage was indicated by the increased SGPt serum levels in the rabbit. The use of Mn-DPDP allowed detection of early hepatocyte necrosis in these animals whereas conventional spin-echo MRI did not. The fact that D-galactosamine curves with and without Mn-DPDP were not significantly different indicated virtually no membrane transport or metabolism of Mn-DPDP in the liver. Ethanol curves were not normal, but there was still considerable residual Mn-DPDP metabolism. Mn-DPDP appears to be an attractive agent in assessing hepatocyte function.

Animals↗

An account of the discrepancy between MRI and PET cerebral blood flow measures. A high-field MRI investigation.

There is controversy concerning the discrepancy between absolute cerebral blood flow (CBF) values measured using positron emission tomography (PET) and magnetic resonance imaging (MRI). To gain insight into this problem, the increased signal-to-noise ratio (SNR) and extended T(1) relaxation times of blood and tissue at 3.0 T were exploited to perform pulsed arterial spin labeling (PASL) MRI measurements as a function of spatial resolution and post-labeling delay. The results indicate that, when using post-labeling delays shorter than 1500 ms, MRI gray matter flow values may become as high as several times the correct CBF values owing to tissue signal contamination by remaining arterial blood water label. For delays above 1500 ms, regional PASL-based CBF values (n = 5; frontal gray matter: 48.8 +/- 3.3(SD) ml/100 g/min; occipital gray matter: 49.3 +/- 4.5 ml/100 g/min) comparable with PET-based measurements can be obtained by using spatial resolutions comparable with PET (5-7.5 mm in-plane). At very high resolution (2.5 x 2.5 x 3 mm(3)), gray matter CBF values were found to increase by 10-20%, a consequence attributed to reduction in partial volume effects with cerebrospinal fluid and white matter. The recent availability of MRI field strengths of 3.0 T and higher will facilitate the use of MRI-based CBF measurements in the clinic.

Blood Flow Velocity↗

MRI of neuronal ceroid lipofuscinosis. I. Cranial MRI of 30 patients with juvenile neuronal ceroid lipofuscinosis.

We studied 30 patients with juvenile neuronal ceroid lipofuscinosis (JNCL). The patients (aged 6-25 years) and 43 age-matched healthy volunteers underwent MRI. After visual assessment, the signal intensity was measured on T2-weighted images in numerous locations. The thickness of the cortex and corpus callosum and the dimensions of the brain stem were measured. Mild to moderate cerebral atrophy was found in 14 of 30 patients, most of them over 14 years of age; 5 older patients had mild to moderate cerebellar atrophy. There was reduction in the size of the corpus callosum and brain stem. The thalamus, caudate nucleus and putamen appeared to give low signal in patients from the ages of 7, 11 and 11 years, respectively. In contrast, the signal intensity measured from the thalamus in these patients showed only a slight (insignificant) decrease compared with controls. The most significant alteration, an increase in measured signal intensity, was found in the white matter (P < 0.0001), even in the youngest patients. The MRI findings correlated significantly with decreased intelligence, speech disturbances and motor problems. Although MRI findings in JNCL do not appear very specific and the visual changes develop relatively late, the absence of pathological MRI findings in the very early stage of the disease may play a part in differential diagnosis of the different types of NCL. Furthermore, the MRI findings may be used in assessing severity and prognosis, particularly in young patients.

Adolescent↗

Meningiomas with conventional MRI findings resembling intraaxial tumors: can perfusion-weighted MRI be helpful in differentiation?

INTRODUCTION: To investigate the contribution of perfusion-weighted MRI to the differentiation of meningiomas with atypical conventional MRI findings from intraaxial tumors. METHODS: We retrospectively analyzed 54 meningiomas, 12 glioblastomas and 13 solitary metastases. We detected 6 meningiomas with atypical features on conventional MRI resembling intraaxial tumors. The regional cerebral blood flow (rCBV) ratios of all tumors were calculated via perfusion-weighted MRI. The signal intensity-time curves were plotted and three different curve patterns were observed. The type 1 curve resembled normal brain parenchyma or the postenhancement part was minimally below the baseline, the type 2 curve was similar to the type 1 curve but with the postenhancement part above the baseline, and the type 3 curve had the postenhancement part below the baseline accompanied by widening of the curve. Student's t-test was used for statistical analysis. RESULTS: On CBV images meningiomas were hypervascular and the mean rCBV ratio was 10.58+/-2.00. For glioblastomas and metastatic lesions, the rCBV ratios were 5.02+/-1.40 and 4.68+/-1.54, respectively. There was a statistically significant difference in rCBV ratios between meningiomas and glioblastomas and metastases (P<0.001). Only one of the meningiomas displayed a type 2 curve while five showed a type 3 curve. Glioblastomas and metastases displayed either a type 1 or a type 2 curve. None of the meningiomas showed a type 1 curve and none of the glioblastomas or metastases showed a type 3 curve. CONCLUSION: Differentiating meningiomas with atypical conventional MRI findings from malignant intraaxial tumors can be difficult. Calculation of rCBV ratios and construction of signal intensity-time curves may contribute to the differentiation of meningiomas from intraaxial tumors.

Aged↗

Sonography, CT, CT sialography, MRI and MRI sialography in investigation of the facial nerve and the differentiation between deep and superficial parotid lesions.

Our aim was to explore the possibility of delineation of the facial nerve within the parotid gland and to differentiate between superficial and deep parotid lesions in relationship to it, using ultrasound, CT, MRI, MRI sialography (MRIS) and CT sialography (CTS). We examined 47 patients with clinically suspected parotid tumours by US, 31 of them also by CT, MRI and CTS, and 13 by MRIS as well. Low-intensity curvilinear structures seen on T1-weighted MRI were delineated better after intraductal gadolinium injection and proved to represent parotid ducts on CTS. Using the main parotid duct as a landmark, we distinguished parotid lesions as deep or superficial to the facial nerve by T1-weighted MRI images in 69% and by MRIS in all cases. The facial nerve itself was indistinguishable from the parotid gland in all our imaging methods.

Adolescent↗

Systematic evaluation of MRI findings in different stages of treatment of cervical cancer: potential of MRI on delineation of target, pathoanatomic structures, and organs at risk.

PURPOSE: To compare magnetic resonance imaging (MRI) findings at different stages of cervix cancer treatment and to define the potential of MRI to delineate the gross tumor volume (GTV), clinical target volume (CTV), pathoanatomic structures, and organs at risk (OAR) in brachytherapy. METHODS AND MATERIALS: Forty-nine patients underwent MRI at diagnosis and at brachytherapy. The ability to discriminate anatomic structures on MRI was assessed (quality factor: 0 = inability to discriminate; 1 = fair discrimination; 2 = good discrimination; 3 = excellent discrimination). The overall ability to visualize (percentage of patients with quality factors greater than 0) and the overall discrimination quality score (mean quality factors of all patients) were estimated for the applicator, GTV at diagnosis (GTV(D)), GTV at brachytherapy (GTV(BT))/"gray zones," cervix rim/uterine corpus, OAR, vaginal wall, and parametria. RESULTS: The overall ability to visualize the applicator on MRI at brachytherapy was 100%; for the GTV(BT)/"gray zones," cervix rim/uterine corpus, OAR, and vaginal wall, visualization was 98% (overall discrimination quality factors: 1.2, 2.9, 2.1, 1.9, 1.7, and 2.6). Three of 4 borders of parametrial space were defined in more than 98% (discrimination quality factors: 2.9, 2.1, and 1.2). CONCLUSION: Magnetic resonance imaging provides appropriate information for definition of the applicator, GTV, CTV, pathoanatomic structures, and OAR that enables precise delineation for cervix cancer brachytherapy.

Adult↗

MRI-clinical correlations: more than inflammation alone-what can MRI contribute to improve the understanding of pathological processes in MS?

Magnetic resonance imaging (MRI) is a sensitive technique in the detection and follow-up of multiple sclerosis (MS) lesions. However, the pathologic basis of these changes is poorly understood. It is becoming increasingly apparent that routine MRI techniques do not represent specific histopathologic changes but reflect a variety of pathological changes in tissue. This review will outline the findings in MRI-pathology correlation in MS to date, and the current understanding of the evolution of pathologic changes in the MS lesion and non-lesional white matter as reflected by MRI. Possible future contributions of MRI to unveiling the dynamic pathology of MS will also be discussed.

Brain↗

Preoperative and postoperative magnetic resonance imaging (MRI) findings of radiculomeningeal arteriovenous malformations: important role of gravity in the symptoms and MRI.

BACKGROUND: The symptoms of radiculomeningeal arteriovenous malformations (AVMs) are reported to be uniform, which suggests it to be a conus medullaris syndrome, and in fact, the lesions on magnetic resonance imaging (MRI) images usually include the conus medullaris. However, the reason why the conus medullaris is always involved in the lesion has not been discussed. METHODS: We encountered seven patients with spinal radiculomeningeal AVMs and operated on all of them. We evaluated the preoperative and postoperative MRI findings in these patients. Postoperative MRI was followed ranging from 6-32 months (mean: 21 months) after surgery. RESULTS: All of our patients showed swelling of the spinal cord, including the conus medullaris, on the preoperative magnetic resonance image. Postoperatively, MRI showed that the swelling of the spinal cord had resolved but that it had finally deteriorated into an atrophic condition. In all of five patients who could be followed up using multiple postoperative MRI scans, sequential T2-weighted images showed that the most rostral level of areas with increased signal in the spinal cord moved in a caudal direction with time. CONCLUSIONS: This and the fact that the conus medullaris was included in the swelling of the spinal cord regardless of the level of the nidus in all our patients, suggested that gravity played an important role in the etiology of radiculomen-ingeal AVM in these patients.

Aged↗

Contrast-enhanced high in-plane resolution dynamic MRI of the breast. Are there advantages in comparison to standard dynamic MRI?

OBJECTIVE: To evaluate the diagnostic advantages of high in-plane resolution contrast-enhanced (CE) magnetic resonance imaging (MRI) of the breast in comparison to standard CE-MRI. METHODS: Forty-one patients with 51 hypervascularized lesions were selected prospectively after undergoing bilateral standard CE MRI (slice thickness 4 mm, in-plane resolution 1.52 x 1.25 mm2, temporal resolution 81 s). Patients underwent high in-plane resolution CE MRI, either (n=21) a two-dimensional fast-low-angle-shot sequence (slice thickness 4 mm, in-plane resolution 0.76 x 0.63 mm2, temporal resolution 96 s) or (n=20) a SE sequence being used (slice thickness 4 mm, in-plane resolution 0.8 x 0.63 mm2, temporal resolution 115 s). RESULTS: Histopathology revealed 33 malignant and 18 benign lesions (0.2-2.2 cm). Morphologic characteristics were much better visualized with high in-plane resolution. Additional diagnostic information, however, resulted only in one patient with fibroadenoma due to a better visualization of smooth contours. CONCLUSIONS: High in-plane resolution provides better visualization of morphologic patterns in comparison to standard dynamic MRI. However, a diagnostic advantage is only rare.

Breast↗

Measurement accuracy of focal cartilage defects from MRI and correlation of MRI graded lesions with histology: a preliminary study.

OBJECTIVES: Although accurate spatial measurement of cartilage thickness from MRI is possible, no studies have assessed the accuracy of measuring cartilage defect dimensions from MRI. In addition, current MR grading scales for assessing cartilage lesions have limited categories, and little is known about how well these scales correlate with histological assessment of the lesion. The objective of this preliminary study is to address both these issues. METHODS: We performed two experiments on four cadaver knee joints from elderly donors: Experiment 1 assessed the accuracy of measuring controlled defects in cartilage, and Experiment 2 compared MRI grading (Noyes scale) of natural cartilage lesions to histological grading (Mankin scale) of the sectioned cartilage tissue. MRI was performed on 1.5 T clinical scanner (fat-suppressed 3D-SPGR at TR/TE/alpha=55/13.5/45 and 256 x 256 matrix). RESULTS: The mean difference between defect diameters measured and introduced was less than 0.1mm, which was statistically insignificant (P=0.754). Defect depth was less accurate at >0.4mm, significantly under predicting actual defect depth (P=0.004). Correlation between Noyes grading scores and Mankin grading scores of natural lesions was moderately high (r=0.7) and statistically significant (P=0.001). CONCLUSIONS: Three-dimensional mapping of cartilage thickness shows great promise for the accurate measurement of focal cartilage defects, though improvement is needed. The Noyes grading scale is consistent with histological Mankin grading of cartilage lesions, though enhancement of MR grading scales is needed, and warranted, based on the signal intensity information available from clinical MRI. Integration of these two analyses-focal defect measurement and signal intensity analysis-could potentially result in a valuable clinical tool for early osteoarthritis diagnosis and longitudinal tracking.

Aged↗

[MRI vs. arthroscopy in the diagnosis of cartilage lesions in the knee. Can MRI take place of arthroscopy?].

INTRODUCTION: The accuracy of magnet resonance imaging in diagnosing cartilage lesions is discussed controversially. The sensitivity of this examination ranges from 15 % to 96 %. Clinical evidence demonstrates that cartilage lesions, diagnosed by MRI, were not confirmed in arthroscopy. The purpose of this prospective study was to analyse the practicability of replacing arthroscopy by MRI in diagnosis of cartilage lesions. PATIENTS AND METHODS: 195 patients with acute or chronic knee pain were examined by reason of a pathological clinic result by MRI preoperatively. In group A (n = 86), a standard program was performed in the radiological department of German Army Hospital (sagittal STIR TSE und PD TSE, coronary und transversal T2 FFE [TR = 660 ms, TE = 18 ms, FA = 30 degrees, 512er-Matrix]), in 21 patients (subgroup AK) a cartilage specific sequence (fs T1 W FFE) without gadolinium was added. Patients in group B (n = 88) were examined in a private outpatient clinic (sagittal T1 SE, T2 SE and T2 FLASH [TR = 608 ms, TE = 18 ms, FA = 20 degrees, 256er-Matrix]) with the use of gadolinium. A clear clinical diagnosis had to be performed before MRI examination. RESULTS: 156 lesions of the cartilage were detected arthroscopically. The sensitivity of the examination was in group A 33 %; group B 53 %; group AK 38 %, specificity in group A 99 %; group B 98 % and group AK 98 %. The positive and negative predictive values were in group A 75 %/98 %; group B 48 %/98 % and in group AK 50 %/97 %. CONCLUSION: MRI was not able to detect reliable cartilage lesions. Until now, arthroscopy is the golden standard to detect cartilage lesions.

Arthroscopy↗

[Cine MRI of the temporomandibular joint in comparison to static MRI and axiography].

PURPOSE: To evaluate Cine MRI (cMRI) of the temporomandibular joint in comparison to static MRI (sMRI) and axiography. MATERIALS AND METHODS: In a prospective study with 57 healthy volunteers as well as 33 patients after temporomandibular joint (TMJ) surgery or with severe joint dysfunction, we measured the mobility of both condyle and disc as well as the sagittal angle of condylar inclination with sMRI and cMRI. Measurements and image analysis were performed by a radiologist and a maxillofacial surgeon in consensus. The results of axiography served as standard of reference. RESULT: Concerning the assessment of the discoligamentous complex, sMRI was superior to cMRI in the patient-group (sensitivity sMRI 85 %, cMRI 76 %), while no significant difference was found in the volunteer-group (sensitivity sMRI 97.4 %, cMRI 98.3 %). The results of cMRI and sMRI showed a highly significant correlation with each other, as well as with the axiographic reference tracings (r = 0.90). The average mobility of the disc and condyle was 6 % and 10 % higher in sMRI compared to cMRI (p = 0.001) and showed a slightly higher variance (0.043 vs. 0.038). Concerning the condylar inclination angle, both MRI-procedures had the best correlation (r = 0.94) with each other and axiography. CONCLUSION: Real-time MRI of the TMJ is comparable to axiography in its accuracy and is a useful adjunct to conventional static MRI.

Adult↗

Localization of breast lesions shown only on MRI--a review for the UK Study of MRI Screening for Breast Cancer. Advisory Group of MARIBS.

The UK study of screening for breast cancer compares mammography and dynamic contrast enhanced MRI of the breast in women at high genetic risk of developing cancer. Owing to the high sensitivity of MR in the breast, it is anticipated that some lesions will be visible only on MR. A key issue for the study is how to localize these lesions for histological verification and removal. This article reviews available methods and describes the current UK expertise and recent European developments. The use of MR compatible wires and markers has been explored in a phantom. The use of these markers in vivo is demonstrated in a case imaged by MR and mammography and further discussed. The susceptibility artefacts produced on MRI, and technical properties associated with these needles, wires and markers are discussed. The clinical pathway by which these lesions will be worked up for the study, and the quality control procedures for keeping the number of such biopsies to a minimum, are described. There is an urgent need for further centres in the UK to become proficient at removing lesions found only on MRI in support of this study and other breast MRI applications. The management of these lesions must be resolved in order to realize the full potential of MRI for screening for breast cancer in women at genetic risk, and for other diagnostic applications.

Algorithms↗

Screening of brain metastasis with limited magnetic resonance imaging (MRI): clinical implications of using limited brain MRI during initial staging for non-small cell lung cancer patients.

The purpose of this prospective study was to determine whether using magnetic resonance imaging (MRI) for early screening for brain metastases (BM) can improve quality of life, survival in patients with non-small cell lung cancer (NSCLC). The study group comprised 183 patients newly diagnosed with NSCLC. All patients underwent limited brain MRI and routine workups. The control group comprised 131 patients with NSCLC who underwent limited brain MRI only if they had neurologic symptoms. The incidence of BM was 20.8% (38/183) in the study group and 4.6% (6/131) in the control group. The rate of upstaging based on the MRI data was 13.5% (15/111) overall and 15.9% (11/69) in patients that had been considered initially to be resectable surgically. There was no significant difference in survival outcome between the groups. Patients who had BM alone had a greater overall survival time (49 weeks) than those who had multiple systemic metastases (27 weeks; p=0.0307). In conclusions, limited brain MRI appears to be a useful, cost-effective method to screen for BM at the time of initial staging. And it may facilitate timely treatment of patients with NSCLC and improve their survival and quality of life.

Adult↗

[A follow-up study by MRI and enhanced-MRI in a case of cerebral tuberculosis].

We report a case of cerebral tuberculosis following miliary tuberculosis. A 54-year-old man was admitted to our hospital in October 1990 because of fever and general fatigue. Chest x-ray film on admission showed diffuse granular shadows in both lungs. Tubercle bacilli were seen in the sputum (Gaffky 5) by the Ziehl Neelsen's staining, and anti-tuberculous therapy was quickly started. But a few days after admission, the disturbance of consciousness, neck stiffness, and headache appeared. The examination of cerebrospinal fluid disclosed that leucocytes was increased in number, and that ADA was elevated to 14.6 IU/l. Tubercle bacilli were detected from cerebrospinal fluid by culture. Although CT scan of the brain was normal at first week of admission, brain CT at eighth week of admission showed several nodulus enhanced with contrast medium. The findings were confirmed by T2 weighted magnetic resonance images (MRI) as high intense areas. Although T1 weighted MRI showed isointensity of the gray matter, T1 weighted MRI enhanced by Gd-DTPA revealed abnormal enhancement. At twenty-ninth week of admission CT showed no abnormality even by contrast enhancement, but enhanced T1 weighted MRI revealed a small lesion with enhancement which was not shown by CT. MRI enhanced by Gd-DTPA was more useful for evaluating cerebral tuberculosis than brain CT.

Brain Diseases↗

MRI of prostatic cancer: in vivo and in vitro MRI results compared with pathological findings.

Magnetic resonance imaging (MRI) of the prostate was accomplished in 23 patients who had prostatic cancer histologically proved by needle biopsy. Five prostates resected out of 23 patients with prostatic cancer were available for in vitro MRI. The MRI findings of the normal peripheral zone of the prostate had a high signal intensity on T2 weighted image, and the cancer nests in the peripheral zone had lower signal intensity than the normal peripheral zone. A partial or total destruction of the border line between outer zone and inner zone was observed besides than microscopic invasions. MRI also enabled us to differentiate the cancerous foci from the normal tissue at a different signal intensity of imaging in some selected cases in which the resected specimen was examined by in vitro MRI.

Aged↗