Results of an International Survey on Spinal Imaging by the ASNR/ASSR/ESNR/ESSR "Nomenclature 3.0" Working Group

Our goal was to determine if "Nomenclature 2.0," the classification of lumbar disk pathology consensus, should be updated. We conducted a social media and e-mail-based survey on preferences regarding the use of classification on magnetic resonance spine reporting. Members of the European Society of Neuroradiology, European Society of Musculoskeletal Radiology, American Society of Neuroradiology, and American Society of Spine Radiology received a 15-question online survey between February and March 2022. A total of 600 responses were received from 63 countries. The largest number of responses came from Italy and the United States. We found that 71.28% of respondents used Nomenclature 2.0, Classification of Lumbar Disk Pathology. But classification on stenosis is used less often: 53.94% and 60% of respondents do not use any classification of spinal canal stenosis and foraminal stenosis, respectively. When queried about which part of Nomenclature needs improving, most respondents asked for a Structured Reporting Template (SRT), even though 58.85% of respondents do not currently use any template and 54% routinely use a clinical information questionnaire. These results highlight the importance of an updated Nomenclature 3.0 version that integrates the classifications of lumbar disk disease and spinal canal and foraminal stenosis. Further attention should also be directed toward developing a robust endorsed SRT.

Apparent Diffusion Coefficient Value Changes and Clinical Correlation in 90 Cases of Cytomegalovirus-Infected Fetuses with Unremarkable Fetal MRI Results

BACKGROUND AND PURPOSE

Cytomegalovirus is the leading intrauterine infection. Fetal MR imaging is an accepted tool for fetal brain evaluation, yet it still lacks the ability to accurately predict the extent of the neurodevelopmental impairment, especially in fetal MR imaging scans with unremarkable findings. Our hypothesis was that intrauterine cytomegalovirus infection causes diffusional changes in fetal brains and that those changes may correlate with the severity of neurodevelopmental deficiencies.

MATERIALS AND METHODS

A retrospective analysis was performed on 90 fetal MR imaging scans of cytomegalovirus-infected fetuses with unremarkable results and compared with a matched gestational age control group of 68 fetal head MR imaging scans. ADC values were measured and averaged in the frontal, parietal, occipital, and temporal lobes; basal ganglia; thalamus; and pons. For neurocognitive assessment, the Vineland Adaptive Behavior Scales, Second Edition (VABS-II) was used on 58 children in the cytomegalovirus-infected group.

RESULTS

ADC values were reduced for the cytomegalovirus-infected fetuses in most brain areas studied. The VABS-II showed no trend for the major domains or the composite score of the VABS-II for the cytomegalovirus-infected children compared with the healthy population distribution. Some subdomains showed an association between ADC values and VABS-II scores.

CONCLUSIONS

Cytomegalovirus infection causes diffuse reduction in ADC values in the fetal brain even in unremarkable fetal MR imaging scans. Cytomegalovirus-infected children with unremarkable fetal MR imaging scans do not deviate from the healthy population in the VABS-II neurocognitive assessment. ADC values were not correlated with VABS-II scores. However, the lack of clinical findings, as seen in most cytomegalovirus-infected fetuses, does not eliminate the possibility of future neurodevelopmental pathology.

Traumatic brain injury imaging research roadmap

The past decade has seen impressive advances in the types of neuroimaging information that can be acquired in patients with traumatic brain injury. However, despite this increase in information, understanding of the contribution of this information to prognostic accuracy and treatment pathways for patients is limited. Available techniques often allow us to infer the presence of microscopic changes indicative of alterations in physiology and function in brain tissue. However, because histologic confirmation is typically lacking, conclusions reached by using these techniques remain solely inferential in almost all cases. Hence, a need exists for validation of these techniques by using data from large population samples that are obtained in a uniform manner, analyzed according to well-accepted procedures, and correlated with closely monitored clinical outcomes. At present, many of these approaches remain confined to population-based research rather than diagnosis at an individual level, particularly with regard to traumatic brain injury that is mild or moderate in degree. A need and a priority exist for patient-centered tools that will allow advanced neuroimaging tools to be brought into clinical settings. One barrier to developing these tools is a lack of an age-, sex-, and comorbidities-stratified, sequence-specific, reference imaging data base that could provide a clear understanding of normal variations across populations. Such a data base would provide researchers and clinicians with the information necessary to develop computational tools for the patient-based interpretation of advanced neuroimaging studies in the clinical setting. The recent "Joint ASNR-ACR HII-ASFNR TBI Workshop: Bringing Advanced Neuroimaging for Traumatic Brain Injury into the Clinic" on May 23, 2014, in Montreal, Quebec, Canada, brought together neuroradiologists, neurologists, psychiatrists, neuropsychologists, neuroimaging scientists, members of the National Institute of Neurologic Disorders and Stroke, industry representatives, and other traumatic brain injury stakeholders to attempt to reach consensus on issues related to and develop consensus recommendations in terms of creating both a well-characterized normative data base of comprehensive imaging and ancillary data to serve as a reference for tools that will allow interpretation of advanced neuroimaging tests at an individual level of a patient with traumatic brain injury. The workshop involved discussions concerning the following: 1) designation of the policies and infrastructure needed for a normative data base, 2) principles for characterizing normal control subjects, and 3) standardizing research neuroimaging protocols for traumatic brain injury. The present article summarizes these recommendations and examines practical steps to achieve them.

Guidelines for the ethical use of neuroimages in medical testimony: report of a multidisciplinary consensus conference

SUMMARY

With rapid advances in neuroimaging technology, there is growing concern over potential misuse of neuroradiologic imaging data in legal matters. On December 7 and 8, 2012, a multidisciplinary consensus conference, Use and Abuse of Neuroimaging in the Courtroom, was held at Emory University in Atlanta, Georgia. Through this interactive forum, a highly select group of experts-including neuroradiologists, neurologists, forensic psychiatrists, neuropsychologists, neuroscientists, legal scholars, imaging statisticians, judges, practicing attorneys, and neuroethicists-discussed the complex issues involved in the use of neuroimaging data entered into legal evidence and for associated expert testimony. The specific contexts of criminal cases, child abuse, and head trauma were especially considered. The purpose of the conference was to inform the development of guidelines on expert testimony for the American Society of Neuroradiology and to provide principles for courts on the ethical use of neuroimaging data as evidence. This report summarizes the conference and resulting recommendations.

Magnetic resonance imaging of spinal cord vascular malformations with an emphasis on the cervical spine

Spinal vascular malformations (AVMs) are rare but important causes of treatable myelopathies. Recent advances in the interventional neuroradiology and neurosurgical techniques have improved the delineation and classification of these heterogeneous lesions. Because MR imaging usually is the first screening test for patients with myelopathy, the neuroradiologist must have a high level of knowledge of the common imaging characteristics of these lesions. This article reviews MR angiographic literature about spinal AVMs, Type I-IV AVMs and cervical Type I AVMs, describes their pathophysiology and common imaging characteristics, and elaborates on differences in cervical location from more typical positions.

Choroid plexus changes after temporal lobectomy

BACKGROUND AND PURPOSE

Postoperative contrast-enhanced MR imaging of the brain is routinely used when evaluating for residual or recurrent brain tumor. It is imperative to be aware of morphologic changes and imaging features that typically occur in response to surgical manipulation at the postoperative site to avoid misinterpretation of imaging findings. Our purpose was to determine normal postoperative changes and alterations in the choroid plexus among patients who had undergone temporal lobectomy in order to distinguish this appearance from pathologic changes that may be seen in the presence of infection or recurrent tumors.

METHODS

We reviewed 159 MR scans from 95 patients with hippocampal sclerosis or gliosis who underwent temporal lobectomy for treatment of intractable epilepsy. Choroid plexus location and size were assessed on contrast-enhanced T1-weighted images.

RESULTS

After temporal lobectomy, the choroid plexus enlarged and sagged into the resection site. Increase in the size of the choroid plexus occurred in 58% of cases overall. The degree of enhancement also increased after surgery, sometimes resulting in a nodular pattern of enhancement. The changes were most marked during the 1st week after temporal lobectomy, and showed an enlarged, markedly enhancing choroid plexus on 86% of the scans.

CONCLUSION

Postoperative changes of the choroid plexus after temporal lobectomy include sagging into the resection site, an increased size, and an increased degree of enhancement. Normal postoperative morphologic characteristics may mimic neoplastic enhancement pattern. Familiarity with this appearance is important to avoid a pitfall in diagnosis of recurrent postoperative temporal lobe neoplasms.

Magnetic resonance imaging in patients with central nervous system pathology: a comparison of OptiMARK (Gd-DTPA-BMEA) and Magnevist (Gd-DTPA)

RATIONALE AND OBJECTIVES

The objective of the two pivotal phase 3 studies was to evaluate the safety and efficacy of OptiMARK (Gd-DTPA-bis(methoxyethylamide) [Gd-DTPA-BMEA]) compared with Magnevist (Gd-DTPA) in magnetic resonance imaging of the central nervous system.

METHODS

Two multicenter, randomized, double-blind, parallel group studies were conducted in 395 patients with known or suspected central nervous system pathology. Subjects were randomized to receive a single 0.1 mmol/kg intravenous injection of either Gd-DTPA-BMEA or Gd-DTPA. The safety of Gd-DTPA-BMEA and Gd-DTPA was monitored for up to 72 hours after study drug administration. Precontrast and postcontrast administration magnetic resonance scans were acquired using identical imaging planes and techniques.

RESULTS

No deaths or unexpected adverse events were reported in either group. A comparison of adverse events by intensity and relation demonstrated no statistically significant differences between the two groups. Gd-DTPA-BMEA and Gd-DTPA were equivalent with respect to confidence in diagnosis, conspicuity, and border delineation.

CONCLUSIONS

Gd-DTPA-BMEA and Gd-DTPA demonstrated comparable efficacy profiles, and the safety profiles were considered similar.

Parenchymal perianeurysmal cystic changes in the brain: report of five cases

PURPOSE

To describe parenchymal perianeurysmal cystic changes in the brain.

MATERIALS AND METHODS

Among 247 patients with cerebral aneurysms described in the medical or radiologic records in three institutions, five had perianeurysmal cystic changes. These were evaluated with computed tomography or magnetic resonance (MR) imaging and were categorized according to size, appearance, and the presence of hemosiderin deposit. Confirmation at stereotactic needle biopsy was available in one case.

RESULTS

Perianeurysmal cysts comprised multiple clustered cysts in three cases and a unilocular cyst in two, and diameters were 1.5-3.5 cm. Hemosiderin was depicted at MR imaging in one unilocular cyst. Associated aneurysms had diameters of 0.7-4.0 cm, and prominent aneurysmal thrombosis and calcifications were seen in two cases. Findings at stereotactic needle biopsy were of mild reactive gliosis. At long-term follow-up in two patients, the cystic regions were stable.

CONCLUSION

Parenchymal perianeurysmal cysts are rare and may display various morphologic characteristics from unilocular to multilocular. Since there may or may not be evidence of previous hemorrhage, other mechanisms such as abnormal angiogenesis factors may play a role.

The potential for vigabatrin-induced intramyelinic edema in humans

PURPOSE

Vigabatrin (Sabril, Hoechst Marion Roussel) is an antiepilepsy drug (AED) presently marketed in 64 countries for the treatment of partial and secondarily generalized seizures. Vigabatrin (VGB) is marketed in a subset of these countries for the treatment of infantile spasms. Clinical experience in humans has shown that VGB provides effective seizure control with a wide margin of safety. However, animal toxicity studies raised concern when prolonged administration of VGB was shown to induce intramyelinic edema (IME) in some laboratory animal species.

METHODS

Animal and human data were reviewed with respect to the potential for VGB-induced IME. Surveillance of patients receiving VGB in clinical trials or by prescription has been conducted for >15 years to identify patients developing clinical abnormalities that might be IME related.

RESULTS

The histologic lesions of VGB-induced IME in animals are reliably reproduced and correlate with changes in multimodality evoked potentials (EPs) and magnetic resonance imaging (MRI). Numerous studies of the effects of VGB on EP and MRI in epilepsy patients have demonstrated no clear-cut IME-related changes in these modalities. Additionally, autopsy and surgical brain samples from VGB-treated patients have been scrutinized for potential IME histopathology. In an estimated 350,000 patient-years of VGB exposure (approximately 175,000 patients exposed for 2 years at an average dose of 2 g/day), no definite case of VGB-induced IME has been identified.

CONCLUSIONS

Comprehensive review of a variety of sources of data failed to identify any definite case of IME in humans treated with VGB.

Pseudohemangioma of the vertebra: an unusual radiographic manifestation of primary Ewing's sarcoma

Primary Ewing's sarcoma (ES) of the spine is uncommon, exhibiting a variety of appearances on plain-film radiographs and cross-sectional images. We report the unusual CT imaging manifestations of a primary ES with a coarse trabecular pattern that mimicked an aggressive hemangioma of the cervical spine.

Colonic stents in colorectal obstruction

Obstruction is the presenting symptom of colorectal cancer in up to 40 per cent of patients. Benign strictures and other neoplasms including lymphoma and gynecologic tumors occur as well. Emergent operative therapy is often suboptimal and associated with significant morbidity and mortality. Our objective was to review our experience with stent placement for colonic obstruction. Seven patients underwent stent placement for a total of eight procedures. There were three patients with unresectable colorectal cancer, two patients with metastatic gynecologic cancer, one patient with rectal lymphoma, and one patient with metastatic cancer of unknown primary. All colonic stents were Wallstents placed by the same endoscopist under fluoroscopic and endoscopic guidance. Stents were successfully placed in all patients without complication. One patient underwent placement of two stents in succession for a long stenosis. Six of seven patients (86%) had resolution of the obstruction and return of bowel function. Five of seven were tolerating a diet within 24 hours. One patient's mental status did not allow for oral intake. Four patients were discharged within 48 hours. Two patients died within the same hospitalization as a result of metastatic disease. One patient was found to have multilevel disease requiring stoma placement. There was no morbidity or mortality associated with stent placement, and 86 per cent of patients had palliation of the obstruction. We conclude that colonic stent placement is a safe and effective therapy for colorectal obstruction at this institution.

Small, patent cerebral aneurysms: atypical appearances at 1.5-T MR imaging

PURPOSE

To determine the frequency and characteristics of small cerebral aneurysms with atypical appearances on magnetic resonance (MR) images.

MATERIALS AND METHODS

MR imaging studies (n = 117) obtained at 1.5 T of small aneurysms (< 1 cm diameter) were prospectively and retrospectively analyzed. Signal intensity characteristics and gadolinium-enhancement patterns in 84 aneurysms (62 patients) were evaluated. The patency of all aneurysms was confirmed at angiography or at the time of surgery.

RESULTS

A characteristic signal void was seen on 62 (53%) of 117 studies. On the remaining 55 (47%) studies, aneurysms had atypical signal intensity that was isointense, heterogeneous, or hyperintense. Contrast-enhanced aneurysms were seen on 27 (53%) of 51 gadolinium-enhanced studies.

CONCLUSION

Atypical MR imaging characteristics were seen in roughly half of cases. These atypical-appearing aneurysms may erroneously be considered to be thrombosed or be mistaken for other common lesions such as small tumors and be dismissed as nonvascular.

Comparison of single- and triple-dose contrast material in the MR screening of brain metastases

PURPOSE

Although studies obtained with triple-dose contrast administration can show more brain metastases than those obtained with single-dose contrast material in patients with multiple metastases, such studies are costly and of limited clinical benefit. Since most patients who undergo screening have negative findings or a single metastasis, this study was performed to compare the clinical utility of single-dose versus triple-dose contrast administration in this large group of patients who could benefit from the possible increased sensitivity in lesion detection.

METHODS

Ninety-two consecutive patients with negative or equivocal findings or a solitary metastasis on single-dose contrast-enhanced MR images underwent triple-dose studies. Findings were compared with a standard of reference composed of panel review and long-term follow-up. Further analysis was performed by comparing results with those obtained by two blinded readers.

RESULTS

In all 70 negative single-dose studies, the triple-dose studies depicted no additional metastases in terms of the standard of reference. No statistically significant difference was seen between the results of the single- and triple-dose studies. For 10 equivocal single-dose studies, the triple-dose study helped clarify the presence or absence of metastases in 50% of the cases. In 12 patients with a solitary metastasis seen on the single-dose study, the triple-dose study depicted additional metastases in 25% of the cases. In the results of one of the two blinded readers, use of triple-dose contrast led to a statistical difference by decreasing the number of equivocal readings but at the expense of increasing the number of false-positive readings.

CONCLUSION

Routine triple-dose contrast administration in all cases of suspected brain metastasis is not helpful. On the basis of our investigation, we conclude that the use of triple-dose contrast material is beneficial in selected cases with equivocal findings or solitary metastasis, although with the disadvantage of increasing the number of false-positive results.

Stroke in a neonate heterozygous for factor V Leiden

Activated protein C resistance is the most common hereditary coagulation abnormality and is caused by the factor V Leiden mutation. A newborn who developed seizures within hours after delivery and was found to have a bihemispheric stroke is described. This patient, determined to be heterozygous for factor V Leiden, is the first reported case of neonatal stroke associated with this common mutation.

Hypophysitis: endocrinologic and dynamic MR findings

PURPOSE

Our purpose was to assess the worth of dynamic MR imaging in the evaluation of vascular changes of the pituitary in patients with lymphocytic hypophysitis.

METHODS

Five patients (four males, one female; 9 to 53 years old) with lymphocytic hypophysitis or infundibuloneurohypophysitis were studied. All patients underwent endocrinologic studies and a series of two to five MR examinations performed over a period of 8 months to 5 years, including a total of nine dynamic imaging studies.

RESULTS

Two patients had panhypopituitarism and three had partial hypopituitarism. Diabetes insipidus was present in four patients. Among the five patients, the pituitary was enlarged in three, of whom two showed improvement on follow-up MR studies. Three patients had a thickened stalk, which improved on subsequent examinations. In all nine dynamic studies, the enhancement time of the whole pituitary was delayed to over 90 seconds, even though five of the nine conventional, simultaneously performed MR studies showed a normal pituitary. The peak time of posterior pituitary enhancement in the first dynamic study was also delayed in all patients (from 60 to 120 seconds). In two patients, normal early enhancement of the posterior pituitary was identified on initial studies but not on subsequent studies.

CONCLUSION

Dynamic MR imaging can display an abnormality of the hypophysial vasculature even if the pituitary disease is seen to regress on the conventional MR study. The delay or even the lack of early enhancement of the posterior pituitary in lymphocytic hypophysitis may be due to secondary inflammatory changes.

Regression of HIV encephalopathy and basal ganglia signal intensity abnormality at MR imaging in patients with AIDS after the initiation of protease inhibitor therapy

PURPOSE

To determine whether protease inhibitors cause regression of periventricular white matter signal intensity abnormalities in patients with human immunodeficiency virus (HIV) encephalopathy and whether the changes on magnetic resonance (MR) images correlate with cognitive improvement.

MATERIALS AND METHODS

MR images were retrospectively and prospectively analyzed in 16 adult patients with HIV encephalopathy. White matter and basal ganglia signal intensity abnormalities on initial long repetition time (TR) images were compared with those on subsequent long TR images in patients who received and in patients who did not receive protease inhibitors. Clinical correlation was obtained.

RESULTS

Of the nine patients receiving protease inhibitors, four showed nearly complete regression, four showed interval stability, and one showed slight progression. Thus, eight patients (89%) demonstrated either stability or improvement in white matter disease, which correlated with cognitive improvement. Of the seven patients not receiving protease inhibitors, six (86%) showed marked progression with a decline in cognitive function and one had no interval change. The difference between the two groups was statistically significant. Of the two patients receiving protease inhibitors who initially had basal ganglia signal intensity abnormalities, one demonstrated resolution and one nearly complete resolution subsequently.

CONCLUSION

Although the patient population is small, protease inhibitors may cause regression of periventricular white matter and basal ganglia signal intensity abnormalities in HIV encephalopathy and may have a role in treatment.

Postoperative changes in the brain: MR imaging findings in patients without neoplasms

PURPOSE

To determine the time course of postoperative changes in the brain by using magnetic resonance (MR) imaging.

MATERIALS AND METHODS

Contrast material-enhanced MR images (32 preoperative, 161 postoperative) in 95 patients who underwent temporal lobectomy for treatment of nonneoplastic epilepsy were evaluated for enhancement pattern at the surgical margin and for the presence of dural enhancement, fluid, and air. Images were obtained 9 hours to 5.6 years after surgery.

RESULTS

Surgical margin contrast enhancement was present and increased from 20 hours to 29 days after surgery. The predominant early (days 0-5) pattern was thin linear enhancement (16 of 18 [89%] images). The later (days 6-29) pattern was thick linear or nodular (tumorlike appearance) (11 of 18 [61%] images). Surgical margin enhancement was absent after day 30, although few data were collected 1-5 months after surgery. Dural enhancement was seen on 96 of 97 (99%) postoperative MR images. Extraaxial fluid was seen on all 46 images obtained during the first 30 days and was absent by day 51. Intracranial air was present on 31 of 35 (89%) images obtained during the first 4 days but was absent after day 5.

CONCLUSION

Knowledge of the evolution of contrast enhancement patterns on postoperative MR images of the brain can help in differentiating benign from neoplastic changes.

Extradural spinal meningioma: MRI

We report a case of extradural spinal meningioma with pathologically proven features of malignant transformation. The MRI findings of extradural spinal meningioma and differences in the findings from intradural meningiomas are discussed.

Pituitary gland enlargement secondary to dural arteriovenous fistula in the cavernous sinus: appearance at MR imaging

PURPOSE

To evaluate pituitary gland size in cases of dural arteriovenous (AV) fistula in the cavernous sinus and to correlate the size with the degree of AV fistula.

MATERIALS AND METHODS

Magnetic resonance images in 21 patients with angiographically proved dural AV fistula of the cavernous sinus were retrospectively reviewed. In four patients, findings obtained before and after embolization therapy were compared.

RESULTS

The 21 patients were divided into group 1 (severe AV fistula) and group 2 (moderate or mild AV fistula). The superior contour of the pituitary gland was convex or flat in group 1 and flat or concave in group 2. The mean height of the pituitary gland was 9.4 mm +/- 1.5 (standard deviation) in group 1 and 6.7 mm +/- 1.2 in group 2 (P = .0002). After embolization therapy, pituitary gland height decreased and signal intensity voids improved in the four patients and no AV fistula was observed in three.

CONCLUSION

In cases of severe dural AV fistula in the cavernous sinus, the pituitary gland is enlarged, which should not be misdiagnosed as pathologic.

Cystic pituitary mass in neurosarcoidosis

An MR examination in a patient with neurosarcoidosis showed an intrasellar cystic mass extending into the suprasellar space. The wall of the mass was thick, it enhanced after administration of contrast material, and it extended into the infundibulum and hypothalamus. Pathologic findings showed noncaseating granulomatous inflammation; the cystic component was considered to be ischemic necrosis of the intracranial sarcoid mass.

Nerve root hypertrophy as the cause of lumbar stenosis in chronic inflammatory demyelinating polyradiculoneuropathy

Two patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) developed signs of lumbar stenosis. Radiologic, intraoperative, and pathologic findings demonstrated lumbar stenosis secondary to nerve root hypertrophy. This syndrome has been demonstrated in hereditary but not acquired demyelinating neuropathies. CIDP should be considered in the differential diagnosis of sciatica and nerve root hypertrophy.

Role of two recently cloned rat liver GSH transporters in the ubiquitous transport of GSH in mammalian cells

Recently our laboratory has cloned both the rat canalicular and sinusoidal GSH transporters (RcGshT and RsGshT, respectively; Yi, J., S. Lu, J. Fernandez-Checa, and N. Kaplowitz. 1994. J. Clin. Invest. 93:1841-1845; and 1995. Proc. Natl. Acad. Sci. USA. 92:1495-1499). The current work characterized GSH transport and the expression of these two GSH transporters in various mammalian cell lines. The average cell GSH levels (nmol/10(6) cells) were 25, 22, 32, 13, and 13 in HepG2, HeLa, CaCo-2, MDCK, and Cos-1 cells, respectively. GSH efflux was temperature dependent and averaged 0.018, 0.018, 0.012, 0.007, and 0.019 nmol/10(6) cells/min from HepG2, HeLa, CaCo-2, MDCK, and Cos-1 cells, respectively. Dithiothreitol (DTT), which stimulates rat sinusoidal GSH efflux, stimulated GSH efflux only in HepG2 and HeLa cells which was partially reversed by subsequent cystine treatment. GSH uptake (1 mM plus 35S-GSH) was temperature dependent, linear up to 45 min, and Na+-independent with average rates of 1.12, 0.91, 0.45, and 0.45 nmol/10(6) cells/30 min for HepG2, HeLa, CaCo-2, MDCK, and Cos-1 cells, respectively. BSP-GSH (2mM), which cis-inhibits sinusoidal GSH uptake in rat liver and HepG2 cells, inhibited GSH uptake only in HeLa cells. mRNA and polypeptide of RcGshT are expressed in all cells whereas those of RsGshT are expressed only in HepG2 and HeLa cells. In conclusion, bidirectional GSH transport, mediated by the "canalicular" GSH transporter, is ubiquitous in mammalian cells. Sinusoidal GSH transporter expression is more restricted, being present in HepG2 and HeLa cells. DTT and BSP-GSH affect GSH transport only in cells expressing the sinusoidal transporter confirming their selective action on this transporter.

Cranial nerve enhancement in the Guillain-Barré syndrome

We report a case of Guillain-Barré syndrome with enhancement of multiple cranial nerves seen with postcontrast MR imaging. Clinical symptoms and electrodiagnostic studies reflected abnormalities of some but not all of the enhancing cranial nerves.

MR of parenchymal neurocutaneous melanosis

Two cases of neurocutaneous melanosis are presented. MR showed hyperintense areas in the brain on short-repetition-time/short-echo-time sequences, compatible with intraparenchymal melanin deposits. No leptomeningeal abnormality was seen.

Substituent-Dependent Nitration of 9-Substituted 9,10-Dihydro-9,10-ethanoanthracenes

Mononitration of 9-substituted ethanoanthracenes, bearing Me, But, F, Br, I, OMe , NO2, CN, CHO or CO2Me substituents at the bridgehead carbon, was found to occur exclusively at the β-positions of the aromatic ring. The mononitro products were isolated, identified by 1H n.m.r. spectroscopy, and their relative proportions were estimated by quantitative g.l.c . and/or by 1H n.m.r. spectroscopy. For all the above substrates the proportion of nitration at the β-position meta to the bridgehead carbon bearing the substituent [to give compounds of the general form (4)] was greater than the proportion of nitration at the corresponding β-position para to the bridgehead substituent [to give compounds of the general form (3)]. Whilst the preferential nitration at the β-positions of the aromatic rings is consistent with the previously reported nitration of 9,10-dihydro-9,10-ethanoanthracene (2a) itself, no observations of this preferential meta attack have been made previously. No correlation could be made of this behaviour with available substituent parameters for the widely sterically and electronically disparate set of substituents used in this study, and the origin of this preferential attack remains unclear. Dinitration in this system was studied only superficially. The influence of the bridgehead substituent together with that of the nitro group already present on one aromatic ring appear to combine with quite unpredictable results in orienting the position of attack of the incoming nitro group onto the other (non-nitrated) aromatic ring.

Comparison of bolus and constant infusion methods of gadolinium administration in MR angiography

PURPOSE

To determine whether the method of delivery of gadolinium can alter optimal small-vessel detail in MR angiography.

METHODS

Six healthy volunteers were studied with MR angiography using both a constant infusion and a bolus method of contrast administration to a total dose of 0.1 mmol/kg. Both three-dimensional time-of-flight and 3-D phase-contrast techniques were used.

RESULTS

Constant infusion did not prove superior to bolus administration of contrast. With both techniques, gadolinium enhancement uniformly improved visualization of small vessels. Delay from the time of contrast administration to scan acquisition decreased vessel enhancement.

CONCLUSIONS

Bolus administration of gadolinium is sufficient to improve small vessel visualization with MR angiography. When a series of contrast-enhanced images is to be obtained, MR angiographic sequences should be obtained first.

MR of the head and neck: comparison of fast spin-echo and conventional spin-echo sequences

PURPOSE

To compare conspicuousness of head and neck lesions on fast spin-echo sequences and conventional spin-echo sequences.

METHODS

Forty consecutive patients with 61 head and neck lesions were evaluated. Lesion conspicuousness was qualitatively compared on conventional spin-echo and fast spin-echo sequences, using both spin-density and T2-weighted images. Thirty-six lesions had surgical or pathologic confirmation, and 25 were assigned a presumptive diagnosis based on clinical evaluation and imaging findings seen on conventional spin-echo T1- and T2-weighted sequences. Forty lesions were related to neoplasms; 21 lesions consisted of infectious, vascular, or inflammatory abnormalities.

RESULTS

Fast spin-echo sequences provided improved lesion conspicuousness in 91% of spin-density images, in 77% of T2-weighted images, and in 84% of the combined spin-density and T2-weighted images.

CONCLUSION

By providing shorter imaging times and equal or superior lesion conspicuousness, long-repetition-time fast spin-echo sequences can replace long-repetition-time conventional spin-echo sequences in evaluation of the head and neck.

MR of primary extraosseous Ewing sarcoma

We present MR imaging findings of a 15-year-old girl with a history of chronic back pain, proved by biopsy to be caused by primary extraosseous Ewing sarcoma, extending into the spinal epidural space. We also demonstrate the involvement of the adjacent structures and encroachment on the intervertebral foramina.

Bidirectional membrane transport of intact glutathione in Hep G2 cells

Rat hepatocytes exhibit bidirectional carrier-mediated transport of reduced glutathione (GSH) across the plasma membrane. Transport of GSH has not been well characterized in human-derived cells. We examined Hep G2 cells as a possible human liver model for GSH homeostasis. Hep G2 cell GSH averaged 25.9 +/- 1.4 nmol/10(6) cells. When Hep G2 cells were incubated in buffer, no GSH appeared in the medium over 2 h. However, after pretreatment with acivicin to inhibit gamma-glutamyl transpeptidase activity, GSH efflux was unmasked and measured 30 +/- 4 pmol x 10(6) cells-1 x min-1, which is comparable to rat hepatocytes. GSH efflux was inhibited by sulfobromophthalein GSH adduct (BSP-GSH) and cystathionine, agents that inhibit sinusoidal efflux in the rat, and was stimulated by adenosine 3',5'-cyclic monophosphate-dependent agents. GSH uptake was measured after cells were pretreated with acivicin and buthionine sulfoximine to prevent breakdown of GSH and resynthesis of GSH from precursors, respectively. In the presence of 4 microCi/ml of [35S]GSH and 10 mM unlabeled GSH, GSH uptake was linear up to 45 min and did not require Na+ or Cl-. GSH uptake exhibited saturability with a maximal velocity of 4.15 +/- 0.23 nmol.mg-1 x 30 min-1, a Michaelis constant of 2.36 +/- 0.26 mM, and two interactive transport sites. BSP-GSH cis-inhibited GSH uptake in a dose-dependent manner with an inhibitory constant of 0.46 +/- 0.05 mM. Inhibition by BSP-GSH (1 mM) of GSH uptake was through a single inhibitor site and was overcome at > 10 mM GSH, which is consistent with competitive inhibition. Similar to the rat, 10 mM extracellular GSH trans-stimulated GSH efflux. These findings may be important in gaining better insights into GSH homeostasis in human liver cells.

Spinal imaging

The application of magnetic resonance imaging has changed the evaluation of most disorders of the spinal axis. Contrast agents improve lesion conspicuousness and new sequences decrease both imaging time and artifacts. Myelography, computed tomography, and angiography continue to have well-defined, albeit limited, roles in spinal imaging.

Inversion-recovery fast spin-echo MR imaging: efficacy in the evaluation of head and neck lesions

To compare the efficacies of fast spin-echo (FSE) and inversion-recovery FSE (IRFSE) magnetic resonance (MR) imaging in evaluating head and neck disorders, the authors evaluated 46 lesions in 23 consecutive patients. Twenty-seven lesions were related to neoplasms; 19 lesions resulted from infectious, allergic, or radiation-induced inflammation. Conventional T1-weighted, FSE, and IRFSE images were obtained in all patients. The FSE and IRFSE images were qualitatively compared in an unblinded manner for conspicuity of lesion margins and extent. IRFSE imaging improved conspicuity of 22 lesions (48%) and showed equal conspicuity of 18 (39%). IRFSE imaging proved most useful for small lesions with long T2 relaxation times that were surrounded by fat. IRFSE imaging improved visibility of small optic nerve gliomas, salivary gland inflammation, peripheral nerve tumors, and small lymph nodes. Early changes secondary to spread of tumor across fascial planes were also well visualized with IRFSE sequences. In six lesions (13%) that did not have long T2 relaxation times, the FSE images provided better conspicuity. The authors conclude that by improving conspicuity of small lesions adjacent to or surrounded by fat, IRFSE sequences can supplement FSE sequences in imaging the head and neck.

Diseases of the intracranial meninges: MR imaging features

Although the meninges are often thought of simplistically as a connective tissue sac that contains the CSF and the contents of the CNS, they are far more complex. Anatomically, they comprise several layers. Pathologically, numerous disease processes may affect the meninges; different processes may even involve different areas of the meninges. These factors all influence the MR imaging characteristics of meningeal lesions. This review briefly discusses the anatomy of the meninges, the MR imaging technique when meningeal disease is suspected, and the appearance of the normal meninges. It then focuses on tumors, infections, cysts, and other lesions that primarily involve the meninges, excluding lesions that secondarily involve the meninges.

Use of the magnetic resonance contrast agent gadodiamide in the central nervous system. Results of a multicenter trial

To investigate the safety and efficacy of the low-osmolar, nonionic contrast agent, gadodiamide injection (Omniscan, Sanofi Winthrop Pharmaceuticals, New York, NY), for magnetic resonance imaging (MRI) of the head and spine, a multicenter study involving 439 patients was done at 15 centers as part of a Phase II/III clinical trial. Unenhanced MRI scans were obtained after which the patients were injected with 0.1 mmol/kg gadodiamide, and the MRI was repeated. The patients' vital signs were monitored, and laboratory studies were conducted. Neurologic status was examined before and after the study. The images were evaluated for contrast enhancement. No patient had any significant adverse event or serious change in clinical status. Abnormalities were found in 80% (351) of all patients studied, and it was found that, in 75% (266) of these, the postgadodiamide injection images were improved or facilitated visualization of lesions compared with preinjection images. The investigators believe that, based on the results of this study, gadodiamide injection is safe and effective for imaging the head and spine. They suggest that future studies further assess and compare the safety parameters of gadodiamide injection with those of other nonionic and ionic gadolinium ligands.

Vasculitis presenting as primary leptomeningeal enhancement with minimal parenchymal findings

In this case of biopsy-proved granulomatous angiitis, MR showed prominent leptomeningeal enhancement with comparatively little parenchymal involvement. Pathologically, granulomatous angiitis chiefly affects small vessels, with a predilection for those in the leptomeninges. Although marked leptomeningeal enhancement is not the most common finding, vasculitis should be added to the differential diagnosis of this MR appearance.

Fast spin-echo MR imaging of the cervical spine: influence of echo train length and echo spacing on image contrast and quality

PURPOSE

To examine the interaction of echo train length and interecho spacing and their effects on image quality and contrast in fast spin-echo sequences of the cervical spine.

METHODS

Forty-three patients with suspected cervical disk disease were prospectively evaluated with fast spin-echo with varying echo train lengths and interecho spacing. A flow phantom was used to confirm findings related to cerebrospinal fluid pulsation. Parameters were manipulated to adjust contrast, signal-to-noise ratio, the effects of artifacts, and the speed of acquisition.

RESULTS

In general, increasing echo train length increased homogeneity and high intensity of cerebrospinal fluid signal and reduced acquisition time; however, it decreased the signal-to-noise ratio of cerebrospinal fluid and cord and increased blurring, and, to a lesser extent, edge enhancement, and "truncation-type" artifact. Increasing interecho space permitted the use of longer echo times but minimally decreased contrast and signal-to-noise ratio of cord and cerebrospinal fluid. In addition, increasing echo spacing increased blurring, edge enhancement, truncation-type, magnetic susceptibility, and motion artifacts.

CONCLUSIONS

For cervical spine imaging, a long echo train length and short echo spacing partially compensate for cerebrospinal fluid flow and produce the best myelographic effect but must be modulated by other constraints, such as artifact production or technical capabilities.

Spinal cord MRI in adult polyglucosan body disease

MRI appearance of adult polyglucosan body disease is described. A 67-year-old man presenting with a chronic progressive degenerative neurologic disorder was found to have marked atrophy of the entire cord, without signal abnormalities on long TR images. Autopsy revealed atrophy of the cord, diffuse gliosis, and numerous corpora amylacea.

MR imaging of the spinal cord: current status and future advances

The advent of MR imaging has dramatically altered the evaluation of suspected myelopathy. MR is far less invasive than traditional imaging techniques and often offers a degree of understanding of an abnormality not previously possible. These achievements have closely followed recent technologic advances, such as the development of contrast agents and the introduction of sequences that permit a reduction in both imaging time and artifacts. The current role of MR in the imaging of spinal cord disorders, including intramedullary tumors, infectious and inflammatory myelitis, demyelinating diseases, vascular lesions, trauma, syringomyelia/hydromyelia, and neurodegenerative disorders, is reviewed. While further improvements will undoubtedly occur, the field of spinal MR imaging appears to be entering a maturing phase.

Neuroradiology of the immunosuppressed state

In recent years, one of the most common reasons for neuroimaging has become the evaluation of the immunosuppressed patient. In this review the radiographic appearances of the common inflammatory and neoplastic conditions affecting the central nervous system in patients with HIV infection, as well as the AIDS-dementia complex, are discussed. Non-AIDS immunocompromised neurologic disease is also examined, with particular emphasis on the effect of various immunosuppressive medications on the brain and spine.

Fast spin-echo imaging in the evaluation of intradural disease of the spine

PURPOSE

Fast spin echo (FSE) images were compared with conventional images in 46 patients with intradural spinal disease to determine their accuracy in the detection and delineation of lesions.

MATERIALS AND METHODS

The images were interpreted by two neuroradiologists, who read individually. A total of 720 blinded readings formed the basis for this evaluation. A gold standard for each patient was selected, based on the blinded readings of the conventional studies.

RESULTS

In the sagittal plane, the FSE sequences were found to have an accuracy of 93% and 93% for the first reader and 93% and 85% for the second reader. For the axial plane, the corresponding figures were 86% and 82% for the first reader and 64% and 77% for the second reader. These figures compared favorably with conventional sequences. Similar delineation of lesions was noted in 78% of cases. In the remaining cases, there were no significant trends.

CONCLUSION

Because of these findings, FSE sequences appear as accurate as conventional sequences. In this study, they were capable of supplanting conventional sequences in the evaluation of intradural pathology of the spine in the sagittal plane, although conventional sequences were still preferred in the axial plane.

Evolution of the infant spinal column: evaluation with MR imaging

The appearance of the normal lumbar spinal column was examined in spinal magnetic resonance images obtained in 50 pediatric patients aged 2 years or less. The ossification centers of the developing vertebral bodies, the cartilage, and the disks were studied with a 1.5-T imager by using both short- and long-repetition-time spin-echo sequences. Many of the structures of the spine were noted to undergo dynamic changes in appearance, both in signal intensity and in morphologic characteristics, with growth. The vertebrae and cartilage, especially, transform markedly in infancy and proceed through three characteristic stages of evolution. Stage I, from birth to 1 month of age, is characterized by markedly hypointense ossification centers and hyperintense, prominent cartilage. Stage II, from approximately 1 to 6 months of age, is characterized by increasing signal intensity in the ossification centers, progressing from the endplates in, and decreasing prominence of the cartilage, Stage III, from approximately 7 months of age on, is characterized by increasingly rectangular and centrally intense vertebral bodies and diminishing cartilage. The variability of the signal intensities, with that of muscle used as the standard, and morphologic characteristics of different components of the spine at different stages of development can create significant confusion. Careful analysis, however, permits one to follow the evolution of the lumbar spine and to date it on the basis of its appearance.

Multicenter study of gadodiamide injection as a contrast agent in MR imaging of the brain and spine

To evaluate the safety and efficacy of gadodiamide injection, a nonionic gadolinium chelate complex, in magnetic resonance (MR) imaging of the head and spine, a phase II-III trial was conducted in 439 patients with known or suspected lesions in the central nervous system. All patients received gadodiamide injection in a dosage of 0.1 mmol/kg and were monitored; MR images were evaluated for contrast material enhancement. No serious adverse events or clinically important trends in vital signs, laboratory values, or neurologic status were observed. Gadodiamide injection enhanced or facilitated the visualization of lesions in 266 or 353 patients (75.4%) in whom lesions were shown on unenhanced images, enhanced images, or both; in these 266 patients, the diagnosis was changed in 76 patients (28.6%) and facilitated in 190 patients (71.4%). It is concluded that gadodiamide injection is safe and effective for MR imaging of the head and spine in patients with suspected abnormalities of the central nervous system.

Magnetic resonance imaging of spinal infection

The findings on magnetic resonance imaging in various types of spinal infection are described, including disc space infection and osteomyelitis, epidural abscess, paraspinal abscesses, and meningitis. The characteristic appearance of spinal infection on both plain and gadolinium-enhanced magnetic resonance is contrasted with that of the normal spine.

Developing spinal column: gadolinium-enhanced MR imaging

Enhancement characteristics of the normally developing spinal column were examined in magnetic resonance (MR) images obtained in 58 children aged 7 days to 9 years. With a 1.5-T imager, short-repetition-time spin-echo images were obtained before and after the administration of 0.1 mmol/kg gadopentetate dimeglumine. Enhancement of normal bone marrow was seen in all patients aged less than 7 years; it was marked only in patients aged less than 2 years. Enhancement of normal cartilage, seen in all patients aged less than 1 1/2 years, may be the most striking feature of enhanced MR images of the infant spine. Enhancement of both bone marrow and cartilage in children appears to be due to the unusual prominence of vasculature, associated with permeability of the capillary endothelium and a plentiful extravascular space. Although marked and diffuse enhancement of vertebral bodies in adults is often thought to indicate a pathologic marrow state, caution must be used before the same criteria are applied to children.