Idiopathic cerebral infarction and upper limb ischemia in neonates.

Idiopathic cerebral infarction is very rare in neonates and has been described as being associated with upper extremity ischemia in a handful of cases. We report on two cases in which no etiology was found and review the literature on this interesting entity.

MRI of trauma and sports-related injuries of tendons and ligaments. Part II: Pelvis and lower extremities.

MRI is highly valuable in evaluation of tendons and ligaments of the lower extremities. In this context, MRI is predominantly used in the setting of trauma and sports-related injuries. Tendons and ligaments have a crucial role in the stability and motion of joints in the peripheral skeleton. Tendinitis, tenosynovitis, tendinosis (degeneration of tendon), partial tear, and complete tear of tendons and ligaments are readily detected by MRI. Although interpretation of signal intensities and differentiation of some of these conditions may be difficult, knowledge of the clinical setting, traumatic circumstances, and mechanism of injury would lead to the proper diagnosis. In this article, traumatic and sports-related injuries of tendons and ligaments of the pelvis, knee, ankle, and foot are systematically reviewed.

MRI of trauma and sports-related injuries of tendons and ligaments. Part I: Spine and upper extremities.

MRI is valuable in evaluation of tendons and ligaments in sports-related injuries. Tendons and ligaments show dark signal intensity on all MR sequences. Alteration in size, shape, continuity, and signal intensity of these structures can be well visualized with MRI. Impingement syndrome is the leading cause of atrophy and degeneration of the rotator cuff. Shape of the acromion, presence of subacromial spur, and involvement in certain sport activities that lead to shoulder instability may cause impingement of the rotator cuff. This article systematically reviews the injuries of tendons and ligaments in the spine, shoulder, elbow, wrist, and hand.

Relationship of the dura, Hofmann's ligaments, Batson's plexus, and a fibrovascular membrane lying on the posterior surface of the vertebral bodies and attaching to the deep layer of the posterior longitudinal ligament. An anatomical, radiologic, and clinical study.

With the advent of computed tomography (CT) and magnetic resonance imaging (MRI), visualization of soft tissue structures in the spinal canal, which were previously undetectable, is possible. This study was undertaken to more accurately identify these soft tissue layers and to determine factors such as when is a disc contained and when is it not; in discography, when the disc leaks, into what layer is the contrast going; or when a nuclear fragment creeps upward or downward, just where is it. The works of Fick, Dommisse, Kikuchi, Schellinger, Hofmann, Batson, and Parke were studied. The professors of anatomy of four major medical schools were consulted along with several neuroradiologists and embryologists. Forty lumbar spines were dissected (20 fresh, 20 preserved). Magnetic resonance imaging scans were taken. Photographs and photomicrographs were made. A fibrous membrane, first mentioned by Fick, can be identified lying anterior to the posterior longitudinal ligament and attaching to the deep layer of the posterior longitudinal ligament. It has been given relatively little attention in the past. This membrane has about one fourth the toughness of the dura and is made up largely of fibrous tissue. The veins of Batson lie on its dorsal surface and pierce it to go ventral to this membrane and enter the vertebral body. Batson's plexus crosses the disc space. The peridural membrane extends from one side to the other, spanning the width of the vertebral body and encircling the bony canal around the outside of the dura. There is a potential space between it and the dura. It does not cross the disc space. A probe can easily be passed posterior or anterior to it, between it and the posterior longitudinal ligament or between it and the vertebral body. We also identified Hofmann's ligament anterior to the dura, attaching the dura to the posterior longitudinal ligament. Laterally, tiny attachments between this fibrovascular membrane and the circumneural sheaths of the spinal nerves can be observed as the nerves enter the foramina. The posterior longitudinal ligament (PLL) is very tough and strong and seldom ruptures. The annulus frequently ruptures. Fragments of nucleus pulposus can creep out at the vertebral rim and get under the PLL and the peridural membrane. Hematoma can form by the same route and have the exact appearance as a sequestrated disc. There is no periosteum inside the vertebral canal. With MRI, hematomas can be differentiated from an extruded fragment. They may cause symptoms similar to an extruded disc but will probably heal with time.(ABSTRACT TRUNCATED AT 400 WORDS)

Magnetic resonance imaging of tendon and ligament abnormalities: Part II. Pelvis and lower extremities.

Magnetic resonance imaging (MRI) has provided an ideal means, unmatched by other preexisting modalities, of examining musculoskeletal abnormalities, particularly those involving tendons and ligaments in the lower extremities. Lack of motion artifact, convenience of application of surface coil, and absence of overlying structures have made the lower extremities ideally suited to MRI. In addition, the abundance of adjacent adipose tissue provides a superb contrast background. Although evaluation of trauma remains the most common reason for MRI examination, many other conditions may also affect tendons and ligaments. As in other soft-tissue, chondral, and osteochondral lesions, MRI provides exquisite details of abnormalities in these structures. Part II of this review systematically reviews the abnormalities of tendons and ligaments in the pelvis and lower extremities.

Magnetic resonance imaging of tendon and ligament abnormalities: Part I. Spine and upper extremities.

Magnetic resonance imaging (MRI) has proven to be an ideal technique for evaluating tendons and ligaments, which, because of their fibrous structure, have a low signal intensity on all sequences. Trauma and a wide variety of other conditions cause aberrations in the normal appearance of these structures, ranging from minor alterations in shape, size, appearance, and continuity to various changes in signal intensity within the tendon, tendon sheath, and ligament on different sequences. The purpose of this paper is to review MRI findings in patients with abnormalities of tendons and ligaments in the spine and upper extremities.

Magnetic resonance imaging of arachnoid cysts.

A retrospective review of magnetic resonance imaging (MRI)-computed tomography (CT) correlation was performed in 29 patients with arachnoid cysts. Short TR, short TE spin echo (SE) pulse sequences provided the best anatomic definition whereas multiple echo long TR, TE sequences allowed comparison of the signal intensity of the cyst with that of cerebrospinal fluid (CSF). Simple arachnoid cysts were isointense while neoplastic, hemorrhagic or inflammatory cysts were hyperintense relative to CSF. The CT differential diagnosis of an arachnoid cyst (depending upon its location) may include other cystic collections such as craniopharyngioma, epidermoid, astrocytoma, and chronic subdural hematoma. However, on MRI the combination of extra-axial location, morphological features, and signal intensity matching that of CSF allows one to make the diagnosis of an uncomplicated arachnoid cyst with confidence.

Gadolinium-DTPA in the evaluation of intradural extramedullary spinal disease.

Gadolinium-DTPA was used in MR imaging of the spine to determine the ability of a contrast agent to increase the detection and characterization of disease in the intradural extramedullary space. Although MR imaging, especially with recent technological improvements, has been shown to be at least competitive with, and often superior to, myelography and postmyelography CT in the study of intramedullary and extradural disease, its use in the assessment of intradural extramedullary disease has been questioned. We selected 12 patients with intradural extramedullary disease as demonstrated by positive CSF cytology and/or myelographic findings and performed MR examinations on them before and after administering gadolinium-DTPA (0.1 mmol/kg). Gadolinium-DTPA was extremely effective in depicting intradural extramedullary disease of the spine. Small nodules of 3 mm, virtually invisible on noncontrast MR scans, enhanced strongly and were easily detected. In addition, leptomeningeal spread of tumor along nerve roots was also visualized, sometimes more readily than by myelography and postmyelography CT. The remarkable sensitivity of gadolinium-DTPA to intradural extramedullary disease assures its role in future MR examinations of the spine.

Focal recurrent hemorrhage on magnetic resonance at 0.5 tesla. An aid to the diagnosis of cryptic cerebral vascular malformations.

The MR appearance of focal recurrent hemorrhage is characteristic and highly suggestive of an underlying cryptic vascular malformation. We reviewed the MR findings in 14 cases (3 biopsy proven), 9 in the brainstem and 5 supratentorial. CT in all cases demonstrated the lesion to be hyperdense before contrast with minimal to moderate enhancement post contrast. The angiograms were negative in all 14 cases demonstrating mass effect in some but no blush or neovascularity. MR showed focal hyperintensities on both short (T1) and long (T2) TR sequences surrounded by a well-circumscribed hypointense rim particularly on the long TR sequence. Focal central hyperintensity is felt to be secondary to the presence of methemoglobin and indicates relatively recent hemorrhage. In our experience hyperintensity in a solitary hemorrhage usually resolves in 4-6 weeks. In 8 cases serial MR studies over 2-3 years demonstrated evidence of repeated hemorrhage as manifested by increases in size and persistent or new hyperintensity. The intense rim due to a short T2 did not correlate with vessels angiographically nor with calcification on the pre-contrast CT and, therefore, does not represent the vascular malformation itself but rather some portion of the hematoma, possibly the hemosiderin laden capsule. Using CT and angiography alone it is difficult to differentiate cryptic arteriovenous malformations from a neoplasm particularly in the brainstem. MR's specific configuration of focal recurrent hemorrhage can make a more definitive diagnosis at 0.5 T as well as at 1.5 T.

Locus of control of disadvantaged high school dropouts: preliminary data.

Normative data were collected on 197 disadvantaged high school dropouts on the dimension of internal-external control. Findings indicate that this group appears to be external but not markedly so, and a short-term intervention program designed to improve academic and vocational skills did not appear to affect locus of control of 33 subjects.

Metabolism in rats in vivo of (2S)[3,3,3-2H3]isobutyrate. Identification of (2-pro-S)methyl group as the source of a proton in dehydrogenation.

(2S)[3,3,3-2H3]Isobutyrate, sodium salt, was synthesized and administered intraperitoneally to normal rats. Urinary organic acids were analyzed by gas chromatography-mass spectrometry. 3-Hydroxyisobutyric acid excreted by the rats, analyzed as both a methyl and an isopropyl ester, was found to be enriched almost exclusively with two deuteriums in the hydroxymethyl moiety of the molecule. This result, together with our previous observation that deuterium of [2-2H1]isobutyrate was lost before the formation of 3-hydroxyisobutyrate, indicates that isobutyric acid is dehydrogenated stereospecifically at the (2-pro-S)methyl and alpha-methine groups. The resulting methacrylate is then hydrated with hydrogen addition to the same side of the molecule as it was abstracted from to produce (S)(+)-3-hydroxyisobutyric acid.

Isolation and identification of S(+)-3-hydroxyisobutyric acid in the urine of rats loaded with isobutyric acid.

3-Hydroxyisobutyric acid has been isolated from the urine of rats loaded with sodium isobutyrate. An optical rotation measurement of the methyl ester derivative shows this compound to be the S(+) stereoisomer. This is the same stereoisomer that has been previously identified in cultures of bacteria incubated with ammonium isobutyrate (Aberhart, D.J. (1977) Bioorg. Chem. 6, 191--201).