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PubMed2001

A new rating scale for age-related white matter changes applicable to MRI and CT.

BACKGROUND AND PURPOSE: MRI is more sensitive than CT for detection of age-related white matter changes (ARWMC). Most rating scales estimate the degree and distribution of ARWMC either on CT or on MRI, and they differ in many aspects. This makes it difficult to compare CT and MRI studies. To be able to study the evolution and possible effect of drug treatment on ARWMC in large patient samples, it is necessary to have a rating scale constructed for both MRI and CT. We have developed and evaluated a new scale and studied ARWMC in a large number of patients examined with both MRI and CT. METHODS: Seventy-seven patients with ARWMC on either CT or MRI were recruited and a complementary examination (MRI or CT) performed. The patients came from 4 centers in Europe, and the scans were rated by 4 raters on 1 occasion with the new ARWMC rating scale. The interrater reliability was evaluated by using kappa statistics. The degree and distribution of ARWMC in CT and MRI scans were compared in different brain areas. RESULTS: Interrater reliability was good for MRI (kappa=0.67) and moderate for CT (kappa=0.48). MRI was superior in detection of small ARWMC, whereas larger lesions were detected equally well with both CT and MRI. In the parieto-occipital and infratentorial areas, MRI detected significantly more ARWMC than did CT. In the frontal area and basal ganglia, no differences between modalities were found. When a fluid-attenuated inversion recovery sequence was used, MRI detected significantly more lesions than CT in frontal and parieto-occipital areas. No differences were found in basal ganglia and infratentorial areas. CONCLUSIONS: We present a new ARWMC scale applicable to both CT and MRI that has almost equal sensitivity, except for certain regions. The interrater reliability was slightly better for MRI, as was the detectability of small lesions.

Aging↗
PubMed1993

Changes of soft-tissue water examined with magnetic resonance and electrical impedance tomography: an in vivo experiment.

The purpose of this study was the examination of short-term changes in soft-tissue water under in vivo conditions. In 12 healthy volunteers the water distribution of a selected slice of the lower limb was examined after change of position and rapid infusion of 0.9% saline solution. Two methods were used for data acquisition: magnetic resonance imaging (MRI) (Repetition Time (TR) = 1600 msec, Inversion Time (TI) = 300 msec, Echo Time (TE) = 22 msec) and electrical impedance tomography (EIT). In orthostatic equilibrium all 12 volunteers demonstrated changes of MR signal intensity and resistivity in the range of 12% and 7%, respectively. After infusion, mean changes of signal intensity and resistivity were 7% and 4%, respectively. The overall correlation of MRI and EIT was -0.96 (p < 0.001). Results indicate that inversion recovery sequences are a sensitive method of detecting in vivo changes of water distribution in selected areas of the body.

Adult↗
PubMed1988

Magnetic resonance imaging of the optic nerve in optic neuritis.

Magnetic resonance imaging (MRI) of the optic nerves using the STIR (short inversion time inversion recovery) sequence was performed in 37 adult patients with a recent or past attack of optic neuritis. MRI revealed high-signal regions in 84% of symptomatic and 20% of asymptomatic nerves. The mean longitudinal extent of lesions was 1 cm. Slow or poor visual recovery was associated with more extensive lesions, or lesions within the optic canal. Disk swelling was usually associated with anterior lesions but also occurred with lesions in the canal. Visual evoked potentials were even more sensitive than MRI in detecting lesions and are still the investigation of choice in suspected demyelinating disease involving the optic nerve.

Adult↗
PubMed2001

FLAIR and magnetization transfer imaging of patients with post-treatment Lyme disease syndrome.

OBJECTIVE: To determine patterns of abnormalities on cerebral MRI that may characterize subgroups of patients with post-treatment Lyme disease syndrome (PTLDS) and to help identify pathomechanisms of disease. METHODS: The authors analyzed the distribution of cerebral lesions in a cohort of 27 patients with PTLDS. A subgroup of eight patients with PTLDS was further studied using whole-brain magnetization transfer ratio measures to identify abnormalities not seen on T2-weighted images. RESULTS: Four patients had focal neurologic deficits, relapsing-remitting disease, and lesions in a distribution typical of MS. Twenty-three patients presented with nonfocal symptoms such as fatigue, subjective memory deficits, and mood disturbance. Twelve of these patients had normal MRI, including the more sensitive fluid-attenuated inversion recovery sequence, 10 had primarily punctate and subcortical lesions, and one patient had multiple periventricular lesions. CONCLUSIONS: In a portion of patients with post-treatment Lyme disease syndrome, white-matter hyperintensities tend to occur in subcortical arteriolar watershed areas and are not specific. Magnetization transfer ratio analysis did not provide evidence for structural abnormalities of the brain parenchyma in patients with nonfocal disease.

Adult↗
PubMed1989

Low-field (0.08 T) magnetic resonance imaging of the pancreas: comparison with computed tomography and ultrasound.

Seventy-four patients referred for computed tomography (CT) and ultrasound examination with a presumptive diagnosis of pancreatic disease have been studied using a low-field (0.08 T) magnetic resonance (MR) imaging instrument. A further 50 patients being examined for non-pancreatic disease were also examined to assess the appearances of the normal pancreas. All the MR examinations were performed using an interleaved saturation-recovery/short inversion time (TI) inversion-recovery sequence. Part or all of the pancreas was seen in 96% of normal cases. In inflammatory disease, MR was more accurate than either CT or ultrasound for diagnosis, whilst for the demonstration of pancreatic tumours, MR was found to be no better or worse than either CT or ultrasound. The use of specific T1 measurement for soft-tissue characterization was not useful because of the large overlap in values between normal, inflamed and malignant pancreatic tissue. T1 measurement was found to be useful in differentiating different pathological fluids.

Adult↗
PubMed1994

Non-invasive assessment of diffuse liver disease by in vivo measurement of proton nuclear magnetic resonance relaxation times at 0.08 T.

44 patients with a range of parenchymal liver diseases diagnosed by biopsy or laboratory investigations underwent proton nuclear magnetic resonance (NMR) relaxometry of the liver at 0.08 T. T1 maps were produced using an interleaved saturation recovery and inversion recovery sequence and T2 maps using a four echo Carr-Purcell-Meiboom-Gill sequence. Significantly raised relaxation times compared with a previously studied group of 42 normal volunteers were found in groups of patients with alcoholic cirrhosis (p < 0.001 for T1 and T2), chronic active hepatitis (CAH) (p < 0.01 for T1 and T2) and minor liver abnormalities (p < 0.01, T2 only). T1 was significantly higher in cirrhotics than in patients with CAH (p < 0.002) and minor abnormalities (p < 0.001). This suggests a role for relaxometry in the confirmation of the presence of cirrhosis (sensitivity = 75%, specificity approximately 97%, taking T1 > 266 ms as a positivity criterion). Reduced T2 values were found in patients with liver iron overload prior to venesection (p < 0.001 versus normals, p < 0.02 versus venesected patients). Although this latter test has relatively low sensitivity and specificity, it may have a role in the monitoring of treatment for iron overload.

Adult↗
PubMed1995

Can high frequency ultrasound and MRI diagnose malignant atheromatous plaque in vitro?

It remains a vital clinical issue how to diagnose malignant atheromatous plaques consisting of ulcerative plaque and hemorrhagic plaque, which are potential risks for thrombosis and the arterial spasm. This study proposes further investigations to develop methods in order to detect this type of lesions by echocardiography. In this study, we tested high frequency (7.5 MHz) US and 1.0 T MRI (T1 weighted SE, STIR; short time inversion recovery sequence, and T1 weighted fat suppression technique) for their precision in the diagnosis of atheromatous plaque as malignant or benign in post mortem human aorta. Ten hemorrhagic plaques were imaged as heterogeneous echo- pattern in the shoulder of plaques covered with high-echo capsule with US; however, these findings were also obtained from 2 of 16 non-hemorrhagic plaques. With T1SE, hemorrhagic plaques were revealed as mixed areas of reduced intensity and high intensity which were differentiated from fatty deposition with T1 weighted fat suppression technique. Ulcerative plaques were revealed as concave shaped plaques and diagnosed correctly with both methods. US was superior to MRI from the viewpoints of examination time and measuring wall thickness. US indicated intimal plus medial thickness of hemorrhagic plaque and non-hemorrhagic plaque at 4.3 + 1.1 mm and 3.0 + 1.0 mm (p < 0.05) respectively. MRI was vulnerable to artifacts and its image was poorer in quality due to its lower resolution: however, probably because of its superior ability to distinguish fatty deposition from hemorrhage, MRI ultimately enabled more accurate diagnosis than US, as long as its image was fairly clear. The overall accuracies were 80% with US and 85.7% with MRI as confirmed by histological tests. From these results, the careful analysis of the two images obtained from US and MRI enables clinical diagnosis of malignant atheromatous plaques.

Aorta↗
PubMed1983

Clinical NMR imaging of the brain in children: normal and neurologic disease.

The results of initial clinical nuclear magnetic resonance imaging of the brain in eight normal and 52 children with a wide variety of neurologic diseases were reviewed. The high level of gray-white matter contrast available with inversion-recovery sequences provided a basis for visualizing normal myelination as well as delays or deficits in this process. The appearances seen in cases of parenchymal hemorrhage, cerebral infarction, and porencephalic cysts are described. Ventricular enlargement was readily identified and marginal edema was demonstrated with spin-echo sequences. Abnormalities were seen in cerebral palsy, congenital malformations, Hallervorden-Spatz disease, aminoaciduria, and meningitis. Space-occupying lesions were identified by virtue of their increased relaxation times and mass effects. Nuclear magnetic resonance imaging has considerable potential in pediatric neuroradiologic practice, in some conditions supplying information not available by computed tomography or sonography.

Brain↗
PubMed1995

MR imaging of bone marrow in children with osteosarcoma: effect of granulocyte colony-stimulating factor.

OBJECTIVE: Granulocyte colony-stimulating factor (GCSF) is used to stimulate myeloid cell production and function in children undergoing chemotherapy for osteosarcoma. We hypothesize that GCSF can cause reconversion of marrow from fatty to hematopoietic and that this change can be detected by MR imaging at sites away from the primary tumor. This benign effect of treatment should not be confused with tumor spread. MATERIALS AND METHODS: MR images of marrow of the affected and contralateral limbs were retrospectively reviewed for 16 patients with osteosarcoma of the femur or tibia; nine of these patients had received GCSF. A grade was assigned to marrow signal intensity at sites away from the tumor, and findings before and after treatment were compared. The validity of MR image interpretation was assessed by comparing the signal intensity of marrow with the histologic appearance of marrow at 19 resection margins. RESULTS: Changes consistent with reconversion were seen on MR images in seven of nine patients who had received GCSF in addition to chemotherapy and in none of seven patients who had received chemotherapy alone. The difference in proportions was statistically significant (p = .006; Fisher's exact test, two tailed). The histologic appearance of marrow at the resection margins agreed with the interpretation of the short-Tl inversion recovery sequence in all cases (100%). CONCLUSION: The findings suggest that GCSF causes changes in the MR imaging appearance of marrow. Histologic correlation supports the hypothesis that these changes are attributable to reconversion from fatty to hematopoietic marrow. Awareness of this finding is important to avoid false-positive diagnosis of marrow metastases.

Adolescent↗
PubMed1996

MR imaging of occult traumatic fractures and muscular injuries of the hip and pelvis in elderly patients.

Recent studies have shown the usefulness of T1-weighted MR imaging for identifying fractures of the proximal femur in elderly patients with negative radiographs after acute trauma [1-4]. The advent of fast spin-echo and fast inversion recovery sequences allows for the rapid identification of a variety of other musculoskeletal injuries of the hip and pelvis that may explain a patient's symptoms but that may not be seen on T1-weighted images. This pictorial essay shows the types of lesions encountered. Lesion prevalence is given for 20 consecutive patients examined.

Acetabulum↗
PubMed1996

MR imaging of the tarsometatarsal joint: analysis of injuries in 11 patients.

OBJECTIVE: We evaluated how well MR imaging revealed ligamentous and bony abnormalities in patients with injuries of Lisfranc's joint. SUBJECTS AND METHODS: We evaluated the studies of 11 patients with plantar hyperflexion injuries of the foot who underwent MR imaging in all three planes using spinecho T1-weighted, fast spin-echo T2-weighted, and short inversion time inversion recovery sequences. In four of the 11 patients, a three-dimensional spoiled gradient-recalled acquisition in the steady-state volume sequence was performed in the coronal plane. For five of the 11 patients, radiographs were available for evaluation. RESULTS: Radiographs revealed tarsometatarsal joint malalignment in all five patients for whom plain films were available, metatarsal fractures in four of these patients, and tarsal fractures in the same four patients. MR imaging showed joint malalignment in all 11 patients and disruption of the Lisfranc's ligament in eight of the 11 patients. In the remaining three patients, normal Lisfranc's ligaments were associated with avulsion fractures of the second metatarsal bases or the medial cuneiform bones. On MR imaging, fractures of the metatarsal bases were evident in 10 of 11 patients. Fractures of the tarsal bones were seen in the same 10 patients. CONCLUSION: MR imaging allows the detection of disruption of the Lisfranc's ligament as well as tarsal and metatarsal fractures and therefore may be a valuable technique in assessing patients after trauma to the tarsometatarsal joints when results of routine radiographs are not conclusive.

Adult↗
PubMed1980

Use of musical scales to display distance to objects in an electronic travel aid for the blind.

An electronic travel aid for the blind has been designed which displays distance to objects in terms of the eight notes of the musical scale. Experiments are described which determine the relationship between the efficacy of various tonal displays and the musical sophistication of the subjects. In particular it is shown that the accuracy of predicting the end of a scale, and hence a collision with an object, is a function of familiarity with the scale. That this accuracy is a function of musical sophistication receives only partial support. As expected, the ascending and descending versions of a scale are, in general, equally effective but, unexpectedly, the hypothesis that the accuracy of predicting the end of a tonal sequence would be an inverse function of the sequence length is confirmed only in the case of one scale, the Ionian or Major scale.

Blindness↗
PubMed2003

Magnetic resonance imaging of the equine foot: 15 horses.

REASONS FOR PERFORMING STUDY: Foot pain is a common cause of equine lameness and there have been significant limitations of the methods available for the diagnosis of the causes of foot pain (radiography, nuclear scintigraphy and ultrasonography). Until recently, magnetic resonance imaging (MRI) in the horse has been limited to examination of cadaver limbs. OBJECTIVES: Our purpose was to 1) describe MRI of the foot in live horses, 2) describe MRI findings in horses with foot pain in which a definitive diagnosis could not be established by alternative means and 3) correlate MRI findings with other methods of clinical investigation. METHODS: The feet of 15 horses with unilateral (12) or bilateral (3), forelimb (14) or hindlimb (1) lameness associated with foot pain of previously ill-defined origin were examined using MRI. The horses were examined in right lateral recumbency under general anaesthesia, with the feet positioned in the isocentre of a flared end 1.5 Tesla GE Signa Echospeed magnet. Images were obtained in sagittal, transverse and dorsal planes using 3-dimensional (3D) T2* gradient echo (GRE), spoiled gradient echo, fat-saturated 3D T2* GRE and short inversion recovery sequences. Image acquisition took approximately 1 h. RESULTS: Abnormalities of the distal interphalangeal joint (DIP) cartilage and/or subchondral bone, periarticular osteophyte formation, distension of the DIP joint capsule with or without synovial proliferation, distension of the navicular bursa with or without evidence of chronic inflammation, surface and core lesions in the deep digital flexor tendon, abnormal signal within the navicular bone, evidence of mineralised fragments in the distal sesamoidean impar ligament, irregular outline of and signal in the medial cortex of the distal phalanx, and an abnormal signal on the dorsal aspect of the distal phalanx consistent with laminitis were identified. CONCLUSIONS: MRI permits the diagnosis of a variety of lesions involving different structures within the foot that cannot be diagnosed using other means, thus enhancing our knowledge of the causes of foot pain. POTENTIAL RELEVANCE: With further experience it is likely that lesions involving other structures will also be identified. Long-term follow-up data is required to determine the prognosis for the injuries described.

Animals↗
PubMed2002

Investigations using magnetic resonance imaging: is neurovascular compression present in patients with essential hypertension?

OBJECT: A possible relationship between neurovascular compression of the rostral ventrolateral medulla oblongata (RVLM) and essential hypertension is investigated using a specifically designed magnetic resonance (MR) imaging method. In conjunction with the ninth and 10th cranial nerves, baroreceptor afferents enter the RVLM, which represents a crucial relay for regulation of autonomic blood pressure. In 1985 Jannetta and coworkers proposed a causal relationship between essential hypertension and intraoperatively observed neurovascular compression of the left RVLM. METHODS: Currently, MR imaging is the method of choice for the assessment of neurovascular relationships at the brainstem. By obtaining axial images of a thin-slice turbo inversion-recovery sequence and three-dimensional time-of-flight MR angiograms (fast imaging with steady-state precision), the authors documented the occurrence of neurovascular contacts with the RVLM at the level of the root entry zones (REZs) of the ninth and 10th cranial nerves in 25 patients with essential hypertension, 30 normotensive volunteers, and 10 patients with renal hypertension. Neurovascular contacts with the REZ at the left RVLM were found in 32% of patients with essential hypertension, 37% of normotensive volunteers, and 20% of patients with renal hypertension. In total, neurovascular contacts on either side of the RVLM were documented in 68% of patients with essential hypertension, 53% of normotensive volunteers, and 50% of patients with renal hypertension. CONCLUSIONS: The results do not support the theory of neurovascular compression in cases of essential hypertension. Findings of neurovascular contacts on MR images are not indications for decompression surgery. For further clarification, however, prospective MR imaging studies should be considered in young patients with essential hypertension in whom the history of high blood pressure is short.

Adult↗
PubMed2006

Ataxia and deafness in a young male: an unusual aetiology.

We report here a case of 18 year old male with tremors of hands, deafness, tendency to fall while walking, drowsiness and double vision of total duration 1(1/2) years. He had internuclear ophthalmoplegia, broken saccades, hypertonia and hyperreflexia of all four limbs, intention tremors, signs of gait and limb ataxia. Pupillary reactions and fundus examination were normal and signs of meningeal irritation or sensory neurological deficit were absent. MRI head and cervical spine with gadolinium enhancement revealed demyelination as evident from multiple oblong foci isointense on T1-weighted images and hyperintense on T2-weighted and fluid attenuated inversion recovery sequences in corpus callosum, sub-cortical white matter, right thalamus, pons and periaqueductal region of midbrain. Ill-defined linear hyperintense signals were observed in cervical spinal cord. No skeletal abnormality was noted in the skull or cervical spine. Oligoclonal bands were present in the cerebrospinal fluid. Brainstem auditory evoked potentials were abnormal, although visual evoked potentials were in normal range. A diagnosis of primary progressive multiple sclerosis (PPMS) was made fulfilling the revised criteria as laid down. In view of its presentation, it is a unique case of PPMS from India.

Adolescent↗
PubMed2006

Sporadic onset Creutzfeldt-Jacob disease: interesting MRI observations.

We describe a 60-year-old woman with "probable" sporadic Creutzfeldt-Jacob disease (CJD) who manifested with two months history of rapidly progressive dementia and abnormal behavior, speech and gait abnormality, excessive sleepiness and myoclonic jerks. Scalp EEG showed diffuse slowing of background activity to delta range and triphasic sharp wave complexes occurring periodically twice in one-second interval. Magnetic resonance Imaging (MRI) of brain revealed high signal intensity on T2 weighted image (T2WI) and fluid attenuated inversion recovery sequences in the caudate and putamen bilaterally. Diffusion weighted images showed bilateral symmetric hyperintense signals in the caudate and putamen. The role of MRI in the diagnosis of CJD is discussed.

Creutzfeldt-Jakob Syndrome↗
PubMed2006

Changes in ocular and nasal signs and symptoms among air crew in relation to air humidification on intercontinental flights.

OBJECTIVE: This study evaluates the influence of air humidification in aircraft on symptoms, tear-film stability, nasal patency, and peak expiratory flow. METHODS: Commercial air crew (N=71) were given a medical examination during eight flights from Stockholm to Chicago and eight flights in the opposite direction. Examinations were done onboard one Boeing 767 aircraft equipped with an evaporation humidifier in the forward part of the cabin. The investigators followed the air crew, staying one night in Chicago and returning with the same crew. Four of the flights had the air humidification device active in-flight to Chicago and deactivated when returning to Stockholm. The other four flights had the inverse humidification sequence. The humidification sequence was randomized and double blind. Hygienic measurements were performed. RESULTS: The humidification increased the relative air humidity by 10% in the 1st row in business class, by 3% in the last row (39th row) in tourist class, and by 3% in the cockpit. Air humidification increased tear-film stability and nasal patency and decreased ocular, nasal, and dermal symptoms and headache. The mean concentration of viable bacteria [77-108 colony-forming units (cfu)/m(3)], viable molds (74-84 cfu/m(3)), and particulate matter (1-8 microg/m(3)) was low, both during the humidified and non-humidified flights. CONCLUSIONS: Relative air humidity is low (10-12%) during intercontinental flights and can be increased by the use of a ceramic evaporation humidifier, without any measurable increase of microorganisms in cabin air. Air humidification could increase passenger and crew comfort by increasing tear-film stability and nasal patency and reducing various symptoms.

Adult↗