Scan-rescan variation of measures derived from brain magnetization transfer ratio histograms obtained in healthy volunteers by use of a semi-interleaved magnetization transfer sequence

SUMMARY

A novel semiinterleaved gradient-echo (GE) sequence for quantitative measurement of magnetization transfer ratio (MTR) is described. With this sequence, several lines of k-space are collected for the non-MT image then several lines are collected for the MT image, thus building up the entire k-space in distinct acquisition blocks, with a good trade-off between motion-induced misregistration and degree of MT effect. The scan-rescan coefficients of variation for several MTR histogram-derived measures from 10 healthy volunteers scanned serially with this semiinterleaved sequence proved to be lower than those achieved using a conventional GE sequence. This sequence may be useful in a clinical environment to measure MTR changes over time more reliably than when acquiring the non-MT and MT images sequentially, which inevitably are affected by patient motion.

Diffusion tensor magnetic resonance imaging in multiple sclerosis

OBJECTIVES

To quantify, using diffusion tensor imaging (DTI), the tissue damage in lesions and normal-appearing white matter (NAWM) from a large cohort of patients with MS and to investigate the magnitude of the correlation between DTI-derived metrics and clinical disability.

METHODS

Dual-echo and DTI scans were obtained from 78 patients with relapsing-remitting, secondary progressive, or primary progressive MS and from 20 normal control participants. Post-contrast T1-weighted images were also obtained from the patients. After creating mean diffusivity (D) and fractional anisotropy (FA) images and image coregistration, D and FA values were measured for 4846 lesions (3207 nonenhancing T1-isointense, 1511 nonenhancing T1-hypointense, and 128 enhancing), 497 NAWM areas from patients, and 160 white matter areas from the controls.

RESULTS

The average lesion D was higher and the average lesion FA was lower than the corresponding quantities of the NAWM (p < 0.001). The values of enhancing and nonenhancing lesions were not different, whereas enhancing lesions had lower FA (p < 0.001). T1-hypointense lesions had higher D and lower FA than T1-isointense lesions (p < 0.001). NAWM of patients had higher and lower FA than white matter of controls (p = 0.01). Significant correlations were found between T1 and T2 lesion volume and and FA of lesions and NAWM. In the overall patient sample, a moderate correlation was also found between lesion D and the Expanded Disability Status Scale score (r = 0.28, p = 0.01). However, the r value of this correlation was 0.48 in patients with secondary progressive MS, whose disability was also correlated with average lesion FA (r = -0.50).

CONCLUSIONS

The results of this study show that DTI is able to identify MS lesions with severe tissue damage and to detect changes in the NAWM. They also indicate that DTI-derived measures are correlated with clinical disability, especially in patients with secondary progressive MS, thus suggesting a role for DTI in monitoring advanced phases of the disease.

Sensitivity and reproducibility of volume change measurements of different brain portions on magnetic resonance imaging in patients with multiple sclerosis

The course of multiple sclerosis (MS) can be monitored by measuring changes in brain volume, but consensus is still lacking on the best strategy to be adopted. We compared the reproducibility and sensitivity of volume measurements from different brain portions for detecting changes on magnetic resonance imaging (MRI) in patients with MS. T1-weighted MRI of the brain was performed in 50 patients with relapsing-remitting MS at study entry and after an average follow-up of 18.4 months. Using a semiautomated technique for brain parenchyma segmentation, the volumes of the following brain portions were measured: (a) the whole brain (whole-brain volume, WBV), (b) the seven slices rostral to the velum interpositum (seven-slice volume, SSV), (c) the central slice of the image set (central-slice volume, CSV) and (d) the infratentorial regions (infratentorial-brain volume, IBV). All these measurements were carried out by a single observer and were repeated twice on ten randomly selected scans to test the intra-observer reproducibility using the four strategies. At follow-up there was a significant decrease in all the measures of brain volume (P ranged from 0.002 to < 0.001). The univariate correlations between changes in WBV, SSV, CSV and IBV were all statistically significant, with the exception of that between changes in CSV and IBV; r values ranged from 0.34 (for the WBV/IBV correlation) to 0.80 (for the WBV/SSV correlation). The mean intra-observer coefficient of variations were 1.9% for WBV, 1.5% for SSV, 2.9% for CSV and 2.2% for IBV measurements. The measurement of volume on a portion of brain selectively including the regions in which MS pathology is more diffuse is as reliable and sensitive to disease-related changes as that on the whole brain, with significant time saving for processing.

Magnetization transfer imaging to monitor the evolution of MS: a 1-year follow-up study

OBJECTIVES

To assess the sensitivities of magnetization transfer imaging (MTI)-derived measures in detecting changes over time of macro- and microscopic lesion burdens in different MS phenotypes and to compare them with those of T2-weighted and T1-weighted lesion volumes.

METHODS

A total of 96 patients were studied: 39 with relapsing-remitting MS (RRMS), 19 with secondary progressive MS (SPMS), nine with primary progressive MS, and nine with benign MS; 20 with clinically isolated syndromes suggestive of MS at presentation; and 20 healthy subjects. Brain T2-weighted, T1-weighted, and MTI scans were obtained at baseline and after 12 months. The authors measured T2-weighted and T1-weighted lesion volumes and average lesion MT ratio (MTR). The authors also derived MTR histograms from whole brain tissue (WBT) and normal-appearing brain tissue (NABT).

RESULTS

In healthy control subjects, there was no significant change of any of the MTR histogram parameters. At follow-up, in the entire patient group, T2-weighted lesion volume significantly increased and average lesion MTR, WBT-MTR, NABT-MTR, and histogram peak positions significantly decreased. Patients with RRMS and SPMS had significantly higher changes in T2-weighted lesion volume and all the MTI-derived metrics compared with the other subgroups. MTI changes were more prominent (and significantly different) in patients with SPMS than in those with RRMS. Compared with patients with benign MS, patients with RRMS had significantly greater changes in T2-weighted lesion volume and WBT- and NABT-MTR metrics. Compared with patients with SPMS, patients with primary progressive MS had similar changes of T1-weighted and T2-weighted lesion volumes, but significantly lower changes of MTI-derived measures.

CONCLUSIONS

MTI-derived measures are sensitive for detecting MS-related changes and might provide valuable outcome measures when assessing treatment effects in clinical trials of patients with MS.

Acute axonal form of Guillain-Barré syndrome in a multiple sclerosis patient: chance association or linked disorders?

Multiple sclerosis (MS) is characterized by inflammation, demyelination and gliosis, involving the central nervous system (CNS) and commonly sparing the peripheral nervous system (PNS). Coexistence of CNS and PNS chronic demyelination has been rarely demonstrated in chronic inflammatory demyelinating polyradiculoneuropathies (CIDP) and in MS, but the occurrence of acute polyradiculoneuropathy in a patient with MS is even more unusual. We describe the case of a woman with relapsing-remitting MS who presented with an acute severe tetraparesis. Cerebrospinal fluid (CSF) examination together with neurophysiological data and sural nerve biopsy study demonstrated an axonal form of Guillain-Barré Syndrome (GBS). It remains unresolved if the association of an axonal form of GBS and MS is fortuitous or, on the contrary, is indicative of the coexistence in some individuals of common pathogenetic mechanisms.

The contribution of fast-FLAIR MRI for lesion detection in the brain of patients with systemic autoimmune diseases

Fast fluid-attenuated inversion recovery (fFLAIR) is more sensitive that conventional or fast spin echo T2-weighted magnetic resonance imaging (MRI) for detecting lesions in the brain of patients with ischemic, inflammatory, or demyelinating diseases of the CNS. We investigated whether the use of fFLAIR also increases the sensitivity of brain MRI assessment in patients with systemic autoimmune disorders. Turbo spin echo (TSE) dual-echo and fFLAIR scans of the brain were obtained from patients affected by systemic lupus erythematosus (SLE) with (NSLE, n = 9) and without clinical CNS involvement (n = 15), Behçet disease (n = 5), Wegener granulomatosis (n = 9), and antiphospholipid antibody syndrome (n = 6). Brain hyperintense lesions were counted and classified according to their size and their location by two observers by consensual agreement. The total lesion volume was measured using a semiautomated technique for lesion segmentation on both TSE and fFLAIR scans. The imaging modalities showed brain hyperintense lesions in all 9 SLE patients with CNS involvement, 5 of 15 SLE patients without CNS involvement, 5 of 9 patients with Wegener granulomatosis, 1 of 5 with Behçet disease, and 3 of 6 with antiphospholipid antibody syndrome. A total of 342 lesions were seen on both sequences; 88 were seen only on TSE and 54 only on fFLAIR scans. The average number of brain lesions per scan was higher on TSE than on fFLAIR, since significantly more discrete (P<0.002) and small (P = 0.004) lesions were seen on TSE than on fFLAIR. The median total lesion volume, however, was similar on TSE and fFLAIR. Our study indicates that the use of fFLAIR does not improve the sensitivity of fast dual-echo MRI for detecting brain abnormalities in patients with systemic autoimmune disorders.

Quantitative brain volumetric analysis from patients with multiple sclerosis: a follow-up study

Using magnetic resonance imaging (MRI), we measured in patients with multiple sclerosis (MS) the brain volume changes over a one year period and correlated them with changes in disability. Three-dimensional T1-weighted magnetization prepared rapid acquisition gradient-echo (MP-RAGE) (with subsequent reconstruction of 1-mm thick axial slices) scans of the brain were obtained at baseline and after one year from 14 MS patients. The average percentage decrease of total brain volume was ten times higher for patients who had a deterioration in their expanded disability status scale (EDSS) scores than for those who had not (mean percentage changes were -4.7 and -0.4%, respectively). Over a short time follow-up period, the decrease of brain volume was higher in the MS patients with clinical evolution compared to those with unchanged disability.

An open-label trial of gabapentin treatment of paroxysmal symptoms in multiple sclerosis patients

We conducted an open-label trial of gabapentin (GBP) as therapy for paroxysmal symptoms (PS) in 21 MS patients, including trigeminal neuralgia (6 patients), painful tonic spasms (11), dysesthetic or paresthetic symptoms (3) and ocular ataxia (1). Complete resolution of symptoms or partial improvement was obtained, respectively, in 14 and 4 of 18 patients who ended the study. Sustained improvement with minor side effects was obtained at dosages ranging from 600 to 1200 mg/d. Our findings suggest that GBP may be effective for PS in MS and warrant a further study in a double-blind placebo-controlled trial.

Effect of copolymer-1 on serial gadolinium-enhanced MRI in relapsing remitting multiple sclerosis

We examined the effect of Copolymer-1 (Cop1) on magnetic resonance (MR) imaging changes in 10 patients with relapsing-remitting multiple sclerosis (RRMS). Monthly gadolinium (Gd)-enhanced MR imaging was performed for 9 to 27 months in the pretreatment period followed by 10 to 14 additional months during Cop1 treatment. MR images were evaluated by two radiologists (F.S. and R.C.P.) masked to the scan date. We found a 57% decrease in the frequency of new Gd-enhancing lesions and in the mean area/month of new Gd-enhancing lesions in the Cop1 treatment period compared with the pretreatment period (0.92 versus 2.20 lesions per month and 22 mm2 versus 43 mm2 area/month; p = 0.1, Wilcoxon signed rank test). Percentage change in lesion load area on T2-weighted images showed a decrease in the accumulation of lesion area during treatment, which was significant for the patient group with a longer pretreatment period (p = 0.05, Friedman test). These results demonstrate a reduction in the number of new Gd-enhancing lesions and in the lesion load during Cop1 treatment compared with the preceding period without therapy and are suggestive of an effect of Cop1 on MR abnormalities observed in multiple sclerosis.

Distinct roles for leukemia inhibitory factor receptor alpha-chain and gp130 in cell type-specific signal transduction

Leukemia inhibitory factor (LIF) induces a variety of disparate biological responses in different cell types. These responses are thought to be mediated through the functional LIF receptor (LIFR), consisting of a heterodimeric complex of LIFR alpha-chain (LIFRalpha) and gp130. The present study investigated the relative capacity of the cytoplasmic domains of each receptor subunit to signal particular responses in several cell types. To monitor the signaling potential of LIFRalpha and gp130 individually, we constructed chimeric receptors by linking the extracellular domain of granulocyte colony-stimulating factor receptor (GCSFR) to the transmembrane and cytoplasmic regions of either LIFRalpha or gp130. Both chimeric receptors and the full-length GCSFR in expressed in M1 myeloid leukemic cells to measure differentiation induction, in embryonic stem cells to measure differentiation inhibition, and in Ba/F3 cells to measure cell proliferation. Our results demonstrated that whereas GCSFR-gp130 receptor homodimer mediated a GCSF-induced signal in all three cell types, the GCSFR-LIFRalpha receptor homodimer was only functional in embryonic stem cells. These findings suggest that the signaling potential of gp130 and LIFRalpha cytoplasmic domains may differ depending upon the tissue and cellular response initiated.

Characterization of tumor necrosis factor-deficient mice

Although tumor necrosis factor (TNF) initially came to prominence because of its anti-tumor activity, most attention is now focused on its proinflammatory actions. TNF appears to play a critical role in both early and late events involved in inflammation, from localizing the noxious agent and amplifying the cellular and mediator responses at the local site and systemically, to editing (e.g., apoptosis) injured cells or effete immune cells and repairing inflammatory damage. We have generated mice deficient in TNF (TNF-/- mice) and have begun to examine the multiple functions attributed to TNF. TNF-/- mice develop normally and have no gross structural or morphological abnormalities. As predicted, they are highly susceptible to challenge with an infectious agent (Candida albicans), are resistant to the lethality of minute doses of lipopolysaccharide (LPS) following D-galactosamine treatment, have a deficiency in granuloma development, and do not form germinal centers after immunization. Phagocytic activity of macrophages appears relatively normal, as do T cell functions, as measured by proliferation, cytokine release, and cytotoxicity. B cell response to thymus-independent antigens is normal, but the Ig response to thymus-dependent antigen is reduced. Surprisingly, cytokine production induced by LPS appears essentially intact, with the exception of reduced colony-stimulating factor activity. Other unexpected findings coming from our initial analysis are as follows. (i) TNF has low toxicity in TNF-/- mice. (ii) TNF-/- mice show an anomalous late response to heat-killed Corynebacterium parvum. In contrast to the prompt response (granuloma formation, hepatosplenomegaly) and subsequent resolution phase in C. parvum-injected TNF+/+ mice, similarly treated TNF-/- mice show little or no initial response, but then develop a vigorous, disorganized inflammatory response leading to death. These results suggest that TNF has an essential homeostatic role in limiting the extent and duration of an inflammatory process-i.e., an anti-inflammatory function. (iii) In contrast to the expectation that TNF+/+ mice and TNF+/- mice would have identical phenotypes, TNF+/- mice showed increased susceptibility to high-dose LPS lethality, increased susceptibility to Candida challenge, and delayed resolution of the C. parvum-induced inflammatory process, indicating a strong gene dose requirement for different actions of TNF.

Intraperitoneal hyperthermic perfusion (IPHP)

Intraperitoneal hyperthermic perfusion (IPHP) with a solution that contains CDDP (25 mg/m(2)/l) and MMC (3.3 mg/m(2)/l) was clinically introduced in the treatment of peritoneal carcinomatosis. Twenty-six patients underwent surgical treatment and IPHP. Peritoneal carcinomatosis was classified at laparotomy using the Japanese classification: P1 (n=3), P2 (n=5), P3 (n=15), unclassifiable (n=3). In this series of patients only the creatinine and amylase values were significant in biological toxicity evaluation. The surgical complication rate (2 duodenal fistulas) does not differ from the general extensive abdominal surgery.

Current results of pelvic perfusion for non-resectable relapsing of pelvic cancer

Twenty-eight patients affected by non-resectable pelvic recurrence of a primary pelvic malignant neoplasm were treated by isolated pelvic perfusion, at mean hyperthermia, with different drugs, chosen taking into account tumor chemosensitivity. All patients had been previously treated. Four complete and six partial responses were observed; nine patients had stable disease and four other patients were non-responders and died due to progression in a few months. Two patients were lost to follow-up, one patients died for other reasons and two recent patients are not yet assessable.