Late evaluation of silent cerebral ischemia detected by diffusion-weighted MR imaging after filter-protected carotid artery stenting.

BACKGROUND AND PURPOSE: Postoperative diffusion-weighted MR imaging (DWI) often discloses new lesions after carotid artery stent placement (CAS), most of them asymptomatic. Our aim was to investigate the fate of these silent ischemic lesions. MATERIALS AND METHODS: We prospectively studied 110 patients undergoing protected transfemoral CAS, 98 of whom underwent DWI before and after the intervention. Patients in whom DWI disclosed silent postoperative lesions also had delayed MR imaging. Preoperative, postoperative, and delayed scans were compared. RESULTS: Of the 92 patients without postoperative symptoms, DWI disclosed 33 new silent ischemic lesions in 14 patients (15.2%), 13 of whom (30 lesions) underwent delayed MR imaging after a mean follow-up of 6.2 months. In 8 of these 13 patients (61%), MR imaging disclosed 12 persistent lesions (12/30, 40%). The reversibility rate depended significantly on the location (cortical versus subcortical) and size (0-5 versus 5-10 mm) of the lesions (P < .05 by chi(2) test). CONCLUSIONS: Because many silent ischemic lesions seen on postoperative DWI after CAS reverse within months, the extent of permanent CAS-related cerebral damage may be overestimated.

Imaging nervous pathways with MR tractography.

This paper describes the state of the art of tractography, a technique which enables the virtual reconstruction of axon bundles of the central nervous system using diffusion-weighted magnetic resonance images. This technique has raised enthusiasm and expectations among specialists because it is the only non-invasive method for studying the three-dimensional architecture of axonal fibres in vivo. Tractography is a new technique used to assess the anatomy of the central nervous system, and it will be available for routine clinical use in the future. Understanding its potential applications and limitations is therefore important.

Turbo-Proton Echo Planar Spectroscopic Imaging (t-PEPSI) MR technique in the detection of diffuse axonal damage in brain injury. Comparison with Gradient-Recalled Echo (GRE) sequence.

PURPOSE: Diffuse axonal injury (DAI) is a common type of primary neuronal injury in patients with severe traumatic brain injury, and is frequently accompanied by tissue tear haemorrhage. The T2*-weighted gradient-recalled echo (GRE) sequences are more sensitive than T2-weighted spin-echo images for detection of haemorrhage. This study was undertaken to determine whether turbo-PEPSI, an extremely fast multi-echo-planar-imaging sequence, can be used as an alternative to the GRE sequence for detection of DAI. MATERIALS AND METHODS: Nineteen patients (mean age 24,5 year) with severe traumatic brain injury (TBI), occurred at least 3 months earlier, underwent a brain MRI study on a 1.5-Tesla scanner. A qualitative evaluation of the turbo-PEPSI sequences was performed by identifying the optimal echo time and in-plane resolution. The number and size of DAI lesions, as well as the signal intensity contrast ratio (SI CR), were computed for each set of GRE and turbo-PEPSI images, and divided according to their anatomic location into lobar and/or deep brain. RESULTS: There was no significant difference between GRE and turbo-PEPSI sequences in the total number of DAI lesions detected (283 vs 225 lesions, respectively). The GRE sequence identified a greater number of hypointense lesions in the temporal lobe compared to the t-PEPSI sequence (72 vs 35, p<0.003), while no significant differences were found for the other brain regions. The SI CR was significantly better (i.e. lower) for the turbo-PEPSI than for the GRE sequence (p<0.00001). CONCLUSIONS: Owing to its very short scan time and high sensitivity to the haemorrhage foci, the turbo-PEPSI sequence can be used as an alternative to the GRE to assess brain DAI in severe TBI patients, especially if uncooperative and medically unstable.

Sex hormones modulate brain damage in multiple sclerosis: MRI evidence.

BACKGROUND: Sex related differences in the course and severity of multiple sclerosis (MS) could be mediated by the sex hormones. OBJECTIVE: To investigate the relation between serum sex hormone concentrations and characteristics of tissue damage on conventional magnetic resonance imaging (MRI) in men and women suffering from relapsing-remitting MS. RESULTS: Serum testosterone was significantly lower in women with MS than in controls. The lowest levels were found in women with a greater number of gadolinium enhancing lesions. A positive correlation was observed between testosterone concentrations and both tissue damage on MRI and clinical disability. In men, there was a positive correlation between oestradiol concentrations and brain damage. CONCLUSIONS: The hormone related modulation of pathological changes supports the hypothesis that sex hormones play a role in the inflammation, damage, and repair mechanisms typical of MS.

A 6-year clinical and MRI follow-up study of patients with relapsing-remitting multiple sclerosis treated with Interferon-beta.

There are few long-term clinical and magnetic resonance imaging (MRI) data on patients treated with interferon-beta (IFN-beta) for relapsing-remitting multiple sclerosis (RRMS). The aim of this study was to provide clinical and MRI data on 68 patients with RRMS treated over a 6-year period and to investigate whether a baseline MRI predicts their long-term clinical and MRI outcome. Six MRI scans were performed monthly before treatment and a further 13 scans were performed during treatment with IFN-beta, the last of which 6 years after commencement of treatment. The relapse rate, disability as measured by the Expanded Disability Status Scale (EDSS), and MRI parameters, including Gd-enhancing lesion load (Gd-LL), T2 hyperintense lesion load (T2-LL) T1 hypointense lesion load (T1-LL) and supratentorial brain volume (SBV) were measured throughout the study. The mean annual relapse rate over the 6 years was 0.52 (SD 0.67), which is significantly lower (68.6%) than the mean annual relapse rate of 1.6 observed during the 2-year period before the commencement of treatment (P < 0.01). The median EDSS score increased from 2 to 2.5, remaining stable in 60% of the patients. From the baseline scan to the final scan, there was a median increase of 7% in the T2-LL and 23.9% in the T1-LL, whilst SBV decreased by 2.7%. The increase in the EDSS over the course of the study was significantly correlated with a reduction in brain volume (r = 0.46, P = 0.001). Greater brain damage at baseline, as measured by both T2-LL and T1-LL, was significantly associated with an increase in disability over the 6 years (r = 0.44, P = 0.0009; r = 0.50, P = 0.0007, respectively). This study shows a sustained effect of IFN-beta on the relapse rate, which is lower than during the 2 years before treatment commencement. More than half the patients showed an improvement or stabilization in the EDSS score. The increment in disability was correlated with the development of brain atrophy but not with increases in lesion burden. Finally, the finding that the extent of lesion burden at the baseline was a strong predictor of increasing disability suggests that IFN-beta treatment might have a moderate effect in modifying the multiple sclerosis (MS) disease course over 6 years unless preventive treatment is started early.

MRI brain volume changes in relapsing-remitting multiple sclerosis patients treated with interferon beta-1a.

The aim of this study was to investigate changes of brain volume as measured by magnetic resonance imaging (MRI) in relapsing-remitting multiple sclerosis (MS) patients under treatment with interferon beta-1a. Moreover, the relationship between brain volume changes and standard MR or clinical outcome variables was determined. After a 6-month pretreatment period, 52 patients with relapsing-remitting MS were assigned to receive interferon beta-1a (Rebif-Serono) during a 24-month treatment period MRI scans were performed monthly during the 6-month pretreatment period and for the first 9 months of the treatment period. A final MRI scan was also performed at the end of the 12- and 24-month treatment period. Over 24 months of IFNbeta-1a treatment, a significant decrease of hyperintense lesion volume was found (-18.0%; p<0.0001) compared to the last pretreatment scan, while T1 hypointense volume showed a slight nonsignificant increase (+2.2%), and brain volume showed a significant decrease (-2.2%; p<0.0001). The mean volume of enhancing lesions over the 6-month pretreatment period was significantly related to absolute (p=0.02; r=-0.32) and per cent change (p=0.03; r=-0.30) of brain volume during 24-month treatment period. No correlations between changes in brain volume and changes in T2 hyperintense volume or T1 hypointense volume were observed. Neither was there a relationship between brain volume and changes of Expanded Disability Status Scale (EDSS) or frequency in clinical relapses. Of the group in whom was detected a significant decrease of brain volume, 13 out of 26 (50%) had a sustained change in EDSS while in the group that did not have a significant decrease of brain volume, only 3 out of 26 (11.5%) had a sustained EDSS change (p=0.02). In this study a decrease of brain volume was found in relapsing-remitting MS patients treated with IFNbeta-1a over 2 years. The only parameter that predicted brain volume decrease by 2 years of IFNbeta-1a treatment was the mean volume of enhancing lesions over the 6-month pretreatment period.

Surgical excision of clival tumors via the enlarged transcochlear approach. Indications and results.

BACKGROUND: The results of the surgical resection of 9 clival tumors using the enlarged transcochlear approach (ETCA) are evaluated. The literature is reviewed to compare the ETCA with other approaches to the clival and petroclival region; the surgical indications are discussed. METHODS: Between June 1996 and June 1997, 9 patients were operated on through the ETCA either alone or combined with other approaches. Only meningiomas and chordomas with a significant involvement of the clivus and huge extension into the posterior fossa were included into this study. RESULTS: Gross total tumor removal was achieved in 5 cases and in 4 cases a residual meningioma was left in place inside the cavernous sinus and treated by radiosurgery. No postoperative mortality or major neurological morbidity were recorded. The postoperative facial nerve function was good in 75% of cases. No tumor recurrence was recorded (mean follow-up = 45.9 months). CONCLUSIONS: The indications to the ETCA should be as strict as possible. The ETCA is an effective procedure in the treatment of large clivopetrous tumors. Tumor characteristics like consistency, vascularity, encasements of vertebro-basilar vessels, bone erosion and previous surgery are also indicative. The transient postoperative facial nerve palsy and deafness should be considered as major disadvantages related to this approach.

MRI of spinal cord in MS.

Over the last 10 - 15 years, magnetic resonance imaging techniques have had a major impact in understanding and managing multiple sclerosis. The present review briefly summarises the current usefulness of spinal cord MRI in MS disease, examining the frequency, distribution and main characteristics of spine MS plaques; the differential diagnosis with other spinal cord disease was also described. Finally we considered how newer imaging sequences when added to semi-automated quantitative methods, may give us a putative tool to reliably quantify subtle changes which develop on the spinal cord of MS patients over time.

Brain atrophy in relapsing-remitting multiple sclerosis: relationship with 'black holes', disease duration and clinical disability.

Recent MRI studies in multiple sclerosis have highlighted the potential role of brain atrophy evaluation as a putative marker of disease progression. In the present study, we evaluated the supratentorial and infratentorial brain volume in patients with relapsing remitting multiple sclerosis (RR MS) and in healthy subjects. Moreover, we determined whether brain volumes of MS patients are associated with different aspects of brain MRI abnormalities and clinical findings. Two-dimensional acquired MRI was performed on 52 relapsing-remitting multiple sclerosis and 30 healthy subjects. The volume of supratentorial and infratentorial structures was measured in selected representative slices. Gd-enhancement, T2 hyperintense, T1 hypointense (i.e. 'black holes') total lesion load, as well as the area of corpus callosum was calculated in the MS group and related to brain volume measures. Correlations between MRI parameters and clinical features were also considered. MS patients had significantly lower supratentorial, infratentorial brain volume and corpus callosum area than healthy subjects (P<0.01). Supratentorial brain volume was significantly related to corpus callosum area (r=0.58; P<0.01) and T1 hypointense lesion load (r=0.48; P<0.01), but not with T2 hyperintense lesion load. Infratentorial/supratentorial ratio was significantly associated with disease duration and EDSS score (r=-0.34; P=0.02 and r=-0.49; P<0.01, respectively). This study documents that brain atrophy is an early MRI finding in RR MS and it is closely related to 'black holes' burden. The use of relative values (infratentorial/supratentorial ratio) may increase the conspicuity of correlation between clinical and MRI findings.

Local versus central assessment of venographies in a multicenter trial on the prevention of deep vein thrombosis in neurosurgery.

Venography is the diagnostic method of choice for end-point measurement in multicenter trials on the prevention of postoperative deep vein thrombosis (DVT). The aim of the study was to determine the inter-observer agreement between the local and central assessment of venographies in a multicenter trial comparing enoxaparin and placebo in the prevention of DVT after elective neurosurgery. The study was run in seven centers experienced in venography trials on DVT prevention. The central and local adjudication panels were both blind with respect to the assigned treatment. The central panel was unaware of the local adjudication. Venographies were adjudicated as positive, negative or inadequate for adjudication and positive venographies as proximal or distal DVT. Inter-observer agreement was assessed according to the Cohen's inter-observer variability index (K index). All 266 venographies (8 monolateral) were considered adequate for adjudication by both the central and local panels. A disagreement was found in 25 cases; K index = 0.75. Fourteen venographies adjudicated as negative centrally were considered positive locally (3 were proximal DVT). Eleven venographies adjudicated as positive centrally (1 was a proximal DVT) were considered negative locally. Enoxaparin was found to be more effective than placebo according to both the central and local adjudication: 16.9% versus 32.6% (Relative risk, RR = 0.52; CI 95% 0.33-0.82) according to central adjudication; 18.5% versus 33.3% (RR = 0.56; CI 95% 0.36-0.87) according to local adjudication. We conclude that a good inter-observer agreement in the assessment of venography was observed between the central and local adjudication in a study on DVT prevention run in a restricted experienced study framework. The cost and work overloading of central assessment of venographies in this study framework seems not to be justified.

Interferon-beta-1a in relapsing-remitting multiple sclerosis: effect on hypointense lesion volume on T1 weighted images.

OBJECTIVE: Recently, a strong correlation between the increase in hypointense lesion load on T1 weighted spin echo images, and the increase in disability was reported. Although the effect of interferon-beta has been demonstrated both in reducing exacerbation rate, frequency of enhancing lesions, and accumulation of disease burden on T2 weighted images, the impact on the accumulation of hypointense lesions has not yet been evaluated. The aims of the present study were: (a) to assess for the first time the effect of interferon-beta-1a on T1 weighted MRI hypointense lesion volume; and (b) to evaluate the relation between changes on hypointense, hyperintense, and enhancing lesion volume before and during interferon-beta-1a treatment in relapsing-remitting multiple sclerosis. METHODS: After a baseline scan and 6 month pretreatment period, 67 patients with relapsing-remitting multiple sclerosis were treated with interferon-beta-1a by subcutaneous injection three times a week during a 12 month treatment period. All patients had MRI every month during the 6 month pretreatment period and for the first 9 months of the treatment period. A final MRI was also performed at the end of the 12 month treatment period. RESULTS: There was a significant increase in the mean hyperintense lesion volume during the pretreatment phase (6 months) and a slight decrease during the treatment period (12 months), whereas the hypointense lesion volume increased significantly before treatment and remained substantially stable during treatment. There was a significant correlation between changes in hypointense and hyperintense lesion volume during the observation period, but not during treatment. The monthly mean volume of Gadolinium-DTPA enhancing lesions was significantly higher during the pretreatment than the treatment period, and the enhancing lesion volume correlated with changes of hyperintense and hypointense lesion volumes only during the observation period. CONCLUSION: These data suggest that interferon-beta-1a has a stabilising effect on T1 weighted hypointense lesion volume.

Use of Bacille Calmette-Guèrin (BCG) in multiple sclerosis.

We studied the effect of Bacille Calmette-Guerin (BCG) vaccine as an immunomodulator in MS. According to the guidelines for clinical trials in MS, a single crossover, MRI-monitored trial was performed in 14 patients with relapsing-remitting MS. After treatment, MRI activity was significantly reduced. No major adverse effects were reported. Adjuvant therapy with BCG vaccine was safe and merits study in MS.

Magnetic resonance imaging outcome of new enhancing lesions in relapsing-remitting multiple sclerosis patients treated with interferon beta1a.

We investigated whether interferon-beta1a modifies the course of new enhancing lesions in relapsing-remitting multiple sclerosis. Sixty-eight patients were studied by monthly magnetic resonance imaging (MRI) in a pretest-posttest design including 6 months of observation and 6 months of treatment. We examined the course of new Gd-enhancing lesions on two consecutive scans during observation and during treatment. Lesions detected during treatment were also analyzed by MRI 1 year later for persistence of enhancement, persistence of T2 hyperintensity, development of T1 hypointensity, or disappearance. Among the enhancing lesions detected by observation and treatment MRI, respectively, Gd-enhancement persisted at 2 months in 20% and 3% (P < 0.001), T2 hyperintensity persisted in 86% and 63% (P < 0.03), and T1 hypointensity developed in 49% and 15% (P < 0.01). Progression to T1 hypointensity was significantly more frequent in larger lesions during both the observation and treatment periods (P < 0.01). No reenhancement of plaques was present at 1-year follow-up; a further reduction in T2 hyperintensity (63% vs. 39%) was observed while T1 hypointensity remained unchanged. Both the duration of Gd enhancement and the short-term MRI course of new enhancing lesions benefited by treatment with recombinant interferon-beta1a treatment.

Fatigue and magnetic resonance imaging activity in multiple sclerosis.

Fatigue is a frequent and often severe symptom in multiple sclerosis. Pathogenic mechanisms proposed for fatigue include the release of proinflammatory cytokines, which is thought to have an important effect on changes in the blood-brain barrier (BBB). To investigate whether fatigue is related to BBB disruption we studied 11 relapsing-remitting MS patients participating in a multicenter longitudinal study comparing the sensitivity of monthly enhanced magnetic resonance imaging (MRI) after standard-dose and triple-dose injection of gadolinium-diethylene triaminopentoacetic acid (Gd-DTPA). Serial Gd-enhanced MRI studies were performed in two separate sessions every 4 weeks for 3 months. An expanded version of the Fatigue Severity Scale, including 29 items, was administered 24 h before each MRI examination. No relationship was found between the number and volume of Gd-enhancing lesions and fatigue scores at any monthly examination over the study period. Furthermore changes in MRI activity were not significantly related to changes in fatigue scores. These results were obtained on triple-dose delayed scanning, which is more sensitive than standard-dose scanning in detecting areas of BBB disruption. Our preliminary results thus do not support the hypothesis of a relationship between BBB alterations and fatigue severity in multiple sclerosis.

Magnetic resonance outcome of new enhancing lesions in patients with relapsing-remitting multiple sclerosis.

The aim of the study was to monitor the natural history of new enhancing lesions in multiple sclerosis (MS) by means of serial gadolinium-enhanced magnetic resonance imaging (MRI). Out of the 63 new enhancing lesions seen on the baseline scan, belonging to 26 relapsing-remitting MS patients, 26 (40%), nine (14%) and four (6%) lesions showed persisting enhancement at first, second and third follow-up scan, respectively. At the end of 5 months of follow-up, 58 (92%) of the new enhancing lesions were detected as T2 hyperintensities, 24 (38%) as T1 hypointensities ('black holes'), and five lesions (8%) disappeared in both T2 and T1 weighted images. Duration of gadolinium enhancement of at least two consecutive scans significantly influenced the development of 'black holes'. No significant correlation was observed between volume, location, configuration of enhancement at baseline and final outcome of the lesion. In individual cases, different evolution of new enhancing lesions was observed at the same time. In conclusion, this study documented that different outcomes of new lesions are unrelated either to the individual patient or to the baseline MRI characteristics. However, prolonged blood-brain-barrier disruption as shown by persisting enhancement significantly influences the lesion outcome.

Sensitivity of enhanced MR in multiple sclerosis: effects of contrast dose and magnetization transfer contrast.

BACKGROUND AND PURPOSES: New strategies have been developed to improve the sensitivity of contrast-enhanced MR imaging in quantifying disease activity in patients with multiple sclerosis (MS). The goal of the present study was to evaluate the sensitivity of T1-weighted images after injection of a triple dose of contrast material and application of a magnetization transfer (MT) pulse in the detection of enhancing lesions as compared with the conventional approach. METHODS: Monthly MR images were obtained in 13 patients with relapsing-remitting MS for a period of 3 months. The MR studies were performed on two separate occasions with single- and triple-dose contrast material. In each session, T1- and T2-weighted spin-echo images with and without the MT pulse were obtained before and after contrast administration. All images were evaluated in a blinded fashion and scored in random order and consensually by two readers. The number of total and new enhancing lesions and active images was counted. RESULTS: Eighty-six percent more enhancing lesions and 54% more new enhancing lesions were detected with triple-dose as compared with single-dose non-MT sequences, whereas single-dose MT images depicted 33% more enhancing lesions and 18% more new enhancing lesions than the single-dose non-MT images. Twenty-nine percent more lesions were detected on triple-dose non-MT images than on single-dose MT images. The combination of a triple dose of contrast material and MT did not produce any significant change in detection of enhancing lesions as compared with a triple dose of contrast without MT. CONCLUSION: The use of a triple dose of contrast material is the best approach to maximize the sensitivity of enhanced MR imaging.

Metastatic prostatic adenocarcinoma presenting as a pituitary mass: shrinkage of the lesion and clinical improvement with medical treatment.

BACKGROUND: Metastatic involvement of the pituitary gland is a very unusual presentation of prostatic cancer. We report a favorable response to medical treatment in such a patient. METHODS AND RESULTS: A 77-year-old man presented with blindness, ophthalmoplegia in his left eye, and mild impairment of memory and mental status. Neuroradiological studies showed a huge intra- and suprasellar lesion that destroyed the sellar floor and extended into the sphenoid sinus. Transsphenoidal biopsy of the lesion demonstrated a prostatic adenocarcinoma. Postoperative studies revealed an enlarged prostate gland and multiple lytic bone lesions. The patient was treated with a combination of leuprolide acetate plus flutamide. Four months later, the patient exhibited a marked improvement in his neurologic status and regained vision in the right eye (visual acuity 6/20). Repeat magnetic resonance imaging of the sellar region confirmed a striking shrinkage of the prostatic metastasis. The clinical status remained stable for 22 months, after which time the disease progressed and the patient died 25 months after beginning treatment. CONCLUSIONS: A favorable response to combined androgen blockade suggests that medical therapy should be considered the therapy of first choice when surgical removal of the metastatic lesion in the pituitary is impossible or too risky.

MRI measures and their relations with clinical disability in relapsing-remitting and secondary progressive multiple sclerosis.

To further evaluate the relationship between clinical disability and Magnetic Resonance Imaging (MRI) lesion burden, we examined 85 patients with clinically definite multiple sclerosis (54 relapsing-remitting and 31 secondary progressive). This cross-sectional study reports on the correlations between total and infratentorial lesion volume on both T1 and T2 weighted images, and overall physical disability measured by Expanded Disability Status Scale, ambulation index and individual functional systems. Assessment of the hypointense lesion load on T1 weighted images rather than the hyperintense lesion load on T2 weighted images at brain MRI was shown to be useful for differentiating relapsing-remitting from secondary progressive Multiple Sclerosis. A weak relationship between disability and total lesion volume on both T1 and T2 weighted images was found in relapsing-remitting Multiple Sclerosis. In secondary progressive Multiple Sclerosis, infratentorial lesion volume on T2 weighted images represents the only marker of disability. Finally, the presence of cerebellar, brainstem and mental impairment was significantly associated to a greater total lesion volume on MRI, while no relationship was found with other functional systems.

Indium-111 pentetreotide single-photon emission tomography in patients with TSH-secreting pituitary adenomas: correlation with the effect of a single administration of octreotide on serum TSH levels.

Few data are available on the visualization of somatostatin receptors in vivo in patients with thyrotropin (TSH)-secreting adenoma. We studied five patients with TSH-secreting adenomas using single-photon emission tomography (SPET) after administration of indium-111 pentetreotide. The intensity of 111In-pentetreotide uptake by the tumours was correlated with the degree of TSH suppression after a single administration of 100 microg octreotide s. c. Five patients (three women and two men) aged 27-46 years were investigated. Except for one patient with acromegaly, all had pure TSH-secreting tumours. One patient was previously untreated, while two had received octreotide, one antithyroid drugs, and one radioiodine. In all patients SPET demonstrated increased uptake of 111In-pentetreotide by the pituitary adenoma. The target to non-target ratio (T/nT) of 111In-pentetreotide uptake was higher than 10 in three patients. Administration of 100 microg octreotide s. c. caused a significant reduction in TSH levels from 4.8+/-1.4 mU/l to a nadir of 3.1+/-1.1 mU/l after 6 h (P<<0.001 by ANOVA). Suppression of TSH secretion ranged from 30% to 60% of the baseline value. The T/nT ratio showed a trend toward a direct relationship with the degree of TSH inhibition after acute octreotide administration (r=0.67; P=NS). Our study showed that 111In-pentetreotide scan visualized somatostatin receptors in all five of the patients with TSH-secreting pituitary adenomas, confirming the frequent presence of somatostatin receptors in these rare tumours, even though the correlation with the TSH inhibition after a single administration of octreotide did not reach significance.