Serial whole-brain magnetization transfer imaging in patients with relapsing-remitting multiple sclerosis at baseline and during treatment with interferon beta-1b.

BACKGROUND AND PURPOSETo determine whether occult disease fluctuates with macroscopic lesions during the natural history of multiple sclerosis (MS) and whether therapeutic interventions affect occult disease, we performed serial monthly magnetization transfer (MT) imaging in patients with relapsing-remitting MS in a crossover trial with interferon beta-lb.METHODSSerial whole-brain magnetization transfer ratios (MTRs) in eight patients with relapsing-remitting MS and in four control subjects were plotted as normalized histograms, and MTR parameters were compared with contrast-enhancing lesions and bulk white matter lesion load.RESULTSIn patients with relapsing-remitting MS, the histographic peak of 0.25+/-0.01 and the histographic mean of 0.21+/-0.01 were statistically lower than corresponding values in control subjects, in whom the histographic peak was 0.27+/-0.01 and the histographic mean was 0.23+/-0.01. When histograms (with MTRs ranging from 0.0 to 0.5) were analyzed by quartiles (quartile 1 to quartile 4) based on histographic area, voxels with low MTRs in quartile 1 (0 to 0.12) increased during the baseline period and corresponded to bulk white matter lesion load. Interferon beta-lb reduced enhancing lesions by 91% and mean bulk white matter lesion load by 15%, but had no effect on MTR in this patient cohort.CONCLUSIONOccult disease in normal-appearing white matter of patients with relapsing-remitting MS measured by MTR parallels the waxing and waning pattern of enhancing lesions and bulk white matter lesion load during the baseline period. MTR is not altered by interferon beta-lb, which raises the possibility of ongoing disease in normal-appearing white matter (not detected by conventional MR sequences).     

Magnetization transfer imaging of periventricular hyperintense white matter in the elderly.

PURPOSETo characterize with magnetization transfer imaging the pathologic substrate of the nonspecific periventricular hyperintense white matter changes seen on T2-weighted images of elderly patients.METHODSTwenty-one elderly patients with periventricular hyperintense white matter on T2-weighted MR images and eleven control subjects were studied using MT technique. Magnetization transfer ratios (MTRs) were calculated for the periventricular hyperintense white matter and normal-appearing white matter. These MTRs were correlated with histopathologic changes that have previously been reported as well as with established MTRs for other lesions.RESULTSThe MTRs (mean, 35.2; SD, 1.2) in the periventricular hyperintense white matter are lower than those in the normal white matter of the patient (mean, 40.8; SD, 1.4) and control (mean, 41.3; SD, 1.8) groups. These MTRs are much higher than those of demyelinating lesions but are similar to those of experimental lesions with just edema.CONCLUSIONBecause MTR may reflect to some extent histopathologic changes and thus provide more specificity than conventional pulse sequences, the main pathologic substrate accounting for the lower MTR in periventricular hyperintense white matter is probably the increased water content in reactive astrocytes.     

Relapsing-remitting multiple sclerosis: metabolic abnormality in nonenhancing lesions and normal-appearing white matter at MR imaging: initial experience

PURPOSE: To quantify, with three-dimensional proton magnetic resonance (MR) spectroscopy, metabolic characteristics of normal-appearing white matter and nonenhancing lesions in patients with relapsing-remitting multiple sclerosis (MS). MATERIALS AND METHODS: Institutional review board approval and informed patient consent were obtained. Nine patients with relapsing-remitting MS (six women, three men) and nine age-matched control subjects (seven women, two men) were studied with T1- and T2-weighted MR imaging and three-dimensional proton MR spectroscopy at spatial resolution less than a cubic centimeter. Absolute N-acetylaspartate (NAA), creatine (Cr), and choline (Cho) levels were obtained from 171 voxels: 66 from lesions on T2-weighted MR images (43 hypointense and 23 isointense on T1-weighted MR images), 31 from normal-appearing white matter, and 74 from analogous normal white matter regions on images in control subjects. RESULTS: Mean NAA level in hypointense lesions (5.30 mmol/L +/- 2.27 [standard deviation]) was significantly lower (P < or = .05) than that in isointense lesions (7.82 mmol/L +/- 2.28), normal-appearing white matter (7.37 mmol/L +/- 1.71), and normal white matter in control subjects (8.89 mmol/L +/- 1.54). Cho (1.79 mmol/L +/- 0.65) and Cr (5.64 mmol/L +/- 1.50) levels in isointense lesions were indistinguishable from those in normal-appearing white matter (1.74 mmol/L +/- 0.46 and 4.99 mmol/L +/- 0.97, respectively) but were significantly higher (Cho, 20%; Cr, 24%) than those in normal white matter in control subjects (1.44 mmol/L +/- 0.40 and 4.30 mmol/L +/- 1.32, respectively). NAA, Cho, and Cr levels in normal-appearing white matter were significantly different than those in normal white matter in control subjects (NAA, 20% lower; Cho, 14% higher; and Cr, 17% higher). CONCLUSION: Abnormal metabolic activity persists in all MS tissue types. Increased Cr and Cho levels suggest (a) ongoing gliosis and attempted remyelination in isointense lesions on T1-weighted MR images and (b) membrane turnover (de- and remyelination), in addition to increased cellularity (gliosis, inflammation) in normal-appearing white matter.     

A comparison of magnetization transfer ratio, magnetization transfer rate, and the native relaxation time of water protons related to relapsing-remitting multiple sclerosis

BACKGROUND AND PURPOSE: Magnetization transfer (MT) imaging and measurements of the magnetization transfer ratio (MTR) have extended our capability to depict and characterize pathologic changes associated with multiple sclerosis (MS). We wanted to investigate whether the analysis of other MT parameters, such as magnetization transfer rate (k(for)) and relative measure of water content (T1(free)), adds insight into MS-related tissue changes. METHODS: Quantitative MT imaging by use of phase acquisition of composite echoes was performed in nine patients with clinically definite relapsing-remitting MS and eight healthy control subjects on a 1.5-T MR system. We analyzed a total of 360 regions of interest and compared control white matter with various types of lesions and normal-appearing white matter in MS. RESULTS: We found a strong correlation between the MTR and k(for), but this relation was non-linear. A slight but significant reduction of the MTR in normal-appearing white matter of patients with MS was attributable to a reduced transfer rate only, whereas a lower MTR was associated with both a reduction of k(for) and an increase of T1(free) in regions of dirty white matter. Moreover, areas such as edema and T1-isointense lesions had a similar MTR but could be differentiated on the basis of Tl(free). CONCLUSION: Estimates of k(for) and T1(free) appear to complement MTR measurements for the understanding of MT changes that occur with different types of MS abnormalities in the brain.     

Patterns of lesion development in multiple sclerosis: longitudinal observations with T1-weighted spin-echo and magnetization transfer MR.

PURPOSEWe evaluated the appearance of enhancing multiple sclerosis (MS) lesions on unenhanced T1-weighted MR images and the natural course of enhancing MS lesions on serial unenhanced T1-weighted and magnetization transfer (MT) MR images.METHODSOne hundred twenty-six enhancing lesions were followed up monthly for 6 to 12 months to determine their signal intensity on unenhanced T1-weighted and MT MR images. At the time of initial enhancement, the size of the lesion and the contrast ratio of enhancement were calculated for each enhancing lesion. During follow-up, the contrast ratio on the corresponding unenhanced T1-weighted image was measured, and an MT ratio (MTR) was calculated.RESULTSTwenty-five enhancing lesions (20%) appeared isointense and 101 lesions (80%) appeared hypointense relative to normal-appearing white matter on unenhanced T1-weighted images. During 6 months of follow-up, four MR patterns of active lesions were detected: initially isointense lesions remained isointense (15%); initially isointense lesions became hypointense (5%, most of which reenhanced); initially hypointense lesions became isointense (44%); and initially hypointense lesions remained hypointense (36%). MTR was significantly lower for hypointense lesions as compared with isointense lesions at the time of initial enhancement. For lesions that changed from hypointense to isointense, MTR increased significantly during 6 months of follow-up. Multiple regression analysis showed that strongly decreased MTR at the time of initial enhancement and enhancement duration of more than one scan were predictive of a hypointense appearance on unenhanced T1-weighted images at 6 months'' follow-up. Ring enhancement was found to be the only (weak) predictor of persistently hypointense signal intensity.CONCLUSIONMost enhancing lesions appear slightly to significantly hypointense on unenhanced T1-weighted images. Although most hypointensities are reversible, only those lesions that fail to recover on unenhanced T1-weighted and MT images may have considerable irreversible structural changes.     

Magnetization transfer measurements in normal-appearing cerebral white matter in patients with chronic obstructive hydrocephalus.

PURPOSE: The purpose of this work was to assess the presence of subtle changes in normal-appearing white matter on T2-weighted MR images in patients with chronic obstructive hydrocephalus using magnetization transfer (MT) measurements. METHOD: In 12 patients with chronic obstructive hydrocephalus, MT ratios (MTRs) of normal-appearing rostral (PR) and caudal (PC) periventricular white matter, of the genu (CG) and the splenium (CS) of the corpus callosum, and of the thalamus (TH) were measured and compared with those of 16 healthy control subjects. RESULTS: We found a significantly lower MTR in chronic obstructive hydrocephalus than in the normal group for PR, PC, CG, and CS but not for TH. CONCLUSION: Our study shows that MT measurements give additional information that cannot be gained by conventional SE MRI, suggesting that chronic obstructive hydrocephalus is associated with diffuse white matter damage that also affects normal-appearing cerebral white matter.     

Progressive multifocal leukoencephalopathy and human immunodeficiency virus-associated white matter lesions in AIDS: magnetization transfer MR imaging

PURPOSE: To determine the magnetization transfer features of progressive multifocal leukoencephalopathy (PML) and human immunodeficiency virus (HIV)-associated white matter lesions (WML) (hereafter, HIV-WML) on magnetic resonance (MR) images obtained in patients with acquired immunodeficiency syndrome (AIDS). MATERIALS AND METHODS: Conventional MR imaging and magnetization transfer MR imaging were performed in 21 AIDS patients with 42 areas of white matter hyperintensity on MR images (13 patients had 25 PML lesions, eight patients had 17 WML). The magnetization transfer ratio was calculated for each lesion. RESULTS: Compared with normal-appearing white matter (magnetization transfer ratio = 47.9%), both PML and HIV-WML showed reduced magnetization transfer ratio. The magnetization transfer ratio was significantly lower in PML lesions (magnetization transfer ratio = 26.1%) than in HIV-WML (magnetization transfer ratio = 38.0%, P < .0001), and there was no overlap in the magnetization transfer ratio between PML lesions and HIV-WML. The separation in magnetization transfer ratio between the two lesion types was valid for lesion as small as 0.5 cm2. CONCLUSION: The larger reduction in magnetization transfer ratio for PML lesions is most likely due to demyelination, whereas the reduction in HIV-WML may be associated primarily with gliosis. PML lesions appear to cause strong reductions in magnetization transfer ratio early in the course of disease. Magnetization transfer MR imaging is a noninvasive tool that improves the differentiation between PML and HIV-WML in patients with AIDS.     

Proton MR spectroscopy of brain abnormalities in neonates born to HIV-positive mothers.

PURPOSETo examine the sensitivity of proton MR spectroscopy for detecting early central nervous system abnormalities in neonates born to human immunodeficiency virus (HIV)-positive mothers.METHODSAsleep, unsedated, and continuously monitored by electrocardiography, 10 newborns, 5 with HIV-positive and 5 with HIV-negative mothers, were studied within the first 10 days of life in a 1.5-T scanner. After T1- and T2-weighted images were obtained, proton spectra were performed using voxels of interest (3.4 cm3) in the deep parietooccipital white matter. Peaks were identified as N-acetyl-aspartate (2.0 ppm), creatine and phosphocreatine (3.0 ppm), choline (3.2 ppm), and inositol (3.5 ppm). Peak areas were used to calculate metabolic ratios: N-acetyl-aspartate to creatine, inositol to creatine, and creatine to choline.RESULTSAll newborns of HIV-positive mothers had abnormal proton spectra compared with control infants; a nonspecific amino acid peak in the 2.1- to 2.6-ppm area was elevated, broad, and overlapping the N-acetyl-aspartate peak in all the HIV-exposed newborns and in only 1 of the 5 control newborns. The choline-to-creatine ratio was higher in HIV-exposed newborns at 2.3 +/- 0.4 (normal term, 0.9 +/- 0.3), as was the N-acetyl-aspartate-to-creatine ratio at 2.6 +/- 0.9 (for control subjects, 1.2 +/- 0.4). MR images from these brain regions were all considered normal. Because acquired immunodeficiency syndrome develops in only a small fraction of neonates born to HIV-seropositive mothers, the above spectral abnormalities found in all our subjects may result from indirect effects of HIV, such as intrauterine growth retardation.CONCLUSIONSThese findings indicate that proton MR spectroscopy might play an important role in detecting early central nervous system complications in newborns of HIV-seropositive mothers.     

Correlation of spectroscopy and magnetization transfer imaging in the evaluation of demyelinating lesions and normal appearing white matter in multiple sclerosis

Magnetization transfer imaging (MT) and localized proton spectroscopy (¹H-MRS) were utilized in the evaluation of lesioins (high signal abnormalities on T₂-weighted images) and normal-appearing white matter (NAWM) in multiple sclerosis (MI). Eleven patients with a clinical diagnosis of MS were independently evaluated with both ¹H-MRS and MT. The magnetization transfer ratio (MTR) of lesions was compared with the relative concentration of Kacetyl-aspartate (NAA) and a composite peak at 2.1 to 2.6 ppm termed “marker peaks”. The MTR of white matter lesions in the MS patients was markedly decreased (6–34%; normal ≈?42%), and correlated well with increase in the marker peaks region (0.94–3.89). There was no correlation between the relative concentration of NAA and MTR. Increased resonance peaks in the 2.1 to 2.6 ppm range and marked decreases in MTR may be a relatively specific indicators of demyelination.     

Huntington disease: volumetric, diffusion-weighted, and magnetization transfer MR imaging of brain

PURPOSE: To investigate whether diffusion-weighted and magnetization transfer (MT) magnetic resonance (MR) imaging depict regional and/or global brain abnormalities in patients with Huntington disease (HD). MATERIALS AND METHODS: Twenty-one carriers of the HD mutation (mean age, 58 years +/- 11 [SD]) and 21 healthy control subjects (mean age, 54 years +/- 13) underwent conventional, diffusion-weighted, and MT MR imaging. Volumes, mean apparent diffusion coefficients (ADCs), and MT ratios (MTRs) for left and right caudate nucleus, putamen, and cerebral periventricular white matter-as well as an index of normalized brain volume and whole-brain ADC and MT histograms-were computed. Asymmetry in volume, ADC, and MTR measurements in caudate nucleus, putamen, and periventricular white matter in control subjects and HD carriers were evaluated with Wilcoxon testing for paired samples. Differences in MR imaging variables between HD carriers and control subjects were evaluated with Mann-Whitney U testing; correlations between stages of clinical severity and MR imaging data were investigated with Spearman rank correlation testing. RESULTS: No significant asymmetry was observed for any of the MR imaging variables. Caudate nucleus, putamen, and whole-brain volumes were smaller (P <.001 for all) in HD carriers than in control subjects. HD carriers also had increased ADC in the caudate nucleus (P =.002), putamen (P <. 001), cerebral periventricular white matter (P <.001), and whole brain (P <.001). MTR was not significantly different between HD carriers and control subjects. Correlation was observed between stages of increasing clinical disease severity and both decrease in volume of caudate nucleus (Spearman rho = -0.63), putamen (rho = -0.64), and whole brain (rho = -0.46) and increase in ADC in caudate nucleus (rho = 0.52), periventricular white matter (rho = 0.45), and whole brain (rho = 0.44). CONCLUSION: Regional and global volume loss in HD is accompanied by an increase in ADC; this correlates with disease severity.     

Multiple sclerosis: magnetization transfer MR imaging of white matter before lesion appearance on T2-weighted images

PURPOSE: To determine the evolution of magnetization transfer (MT) in white matter regions before and after plaque development in patients with multiple sclerosis (MS). MATERIALS AND METHODS: In a 5-year longitudinal evaluation, 30 patients with MS underwent conventional magnetic resonance (MR) imaging, MT MR imaging, and clinical assessment. Cross-sectional data in 12 healthy subjects were also collected. Semiautomated lesion classification with use of T2-weighted MR images was used to measure the time course of the MT ratio (calculated with MR data acquired without and with MT saturation) in every voxel and to help analyze the relationship with the status of lesions depicted on T2-weighted images. RESULTS: There was a significant (P <.001) temporal decline in lesion MT ratio after lesion appearance on T2-weighted images. A significant (P <. 001) progressive decline in MT ratio was also present in voxels that later became lesions, prior to initial detection on T2-weighted images. Even 1(1/2) years prior to lesion appearance, the MT ratio (33.3%) in regions destined to become such lesions was significantly (P <.001) lower than that in both white matter in healthy subjects (41.3%) and other normal-appearing white matter in patients with MS (38.1%). CONCLUSION: The MT ratio reveals progressive focal abnormalities in MS that antedate by up to 2 years the appearance of lesions on T2-weighted MR images.     

Long-term changes of magnetization transfer-derived measures from patients with relapsing-remitting and secondary progressive multiple sclerosis.

BACKGROUND AND PURPOSE: For cases of multiple sclerosis (MS), magnetization transfer (MT) imaging may provide more pathologically specific and accurate estimates of the disease process than does conventional imaging. In this study, we evaluated changes of the MT ratio (MTR) of newly enhancing lesions, the MTR of normal-appearing white matter (NAWM), the average lesion MTR, and the MT histogram-derived metrics during a 3-year follow-up period for patients with relapsing-remitting or secondary progressive MS. METHODS: Dual-echo, conventional spin-echo, and MT images were obtained from seven patients with relapsing-remitting MS, seven patients with secondary progressive MS, and five age- and sex-matched control subjects at the time of study entry and 1, 13, and 37 months later. RESULTS: Newly enhancing lesions in the patients with secondary progressive MS presented a more severe and significant MTR reduction during the follow-up period as compared with those in the relapsing-remitting group. In cases of secondary progressive MS, we also observed a significant reduction of the MTR values of the NAWM and a trend toward reduction of average lesion MTR values. The patients with MS had mean percentage changes of MT histogram-derived measures that were approximately two to 10 times higher than those of the control subjects. CONCLUSION: This preliminary 3-year follow-up study shows that newly enhancing lesions and NAWM in patients with secondary progressive MS have significantly lower MTR values than do those in patients with relapsing-remitting MS. It also shows that the tissue damage that remains after enhancement ceases is more severe in secondary progressive disease.     

Magnetization transfer ratio histogram analysis of normal-appearing gray matter and normal-appearing white matter in multiple sclerosis.

PURPOSE: The purpose of this work was to determine the extent of disease and disease severity in the conventional MR normal-appearing gray matter (NAGM) and white matter (NAWM) in patients with relapsing-remitting (RR) and secondary progressive (SP) multiple sclerosis (MS) utilizing quantitative magnetization transfer ratio (MTR) histogram analysis. METHOD: Twenty-seven patients with MS (16 RR, 11 SP) and 16 healthy control subjects were studied. MTR was calculated in the totally segmented GM and WM without T2 lesions in each group. RESULTS: Each of the RR and SP MS patient groups had significantly smaller MTR histogram mean values in NAGM and NAWM than the healthy subjects (p 相似文献   

Magnetisation transfer ratio is low in normal-appearing cerebral white matter in patients with normal pressure hydrocephalus

We measured the magnetisation transfer ratios (MTR) of normal-appearing rostral (PR) and caudal (PC) periventricular white matter, the genu (CG) and the splenium (CS) of the corpus callosum and the thalamus (TH) in 12 patients with normal-pressure hydrocephalus (NPH) and compared them with 16 healthy control subjects. We found a significantly lower MTR in the NPH group than in the normal group for PR, PC, CG, and CS but not for TH. MT measurements give additional information which cannot be gained by conventional MRI, suggesting that NPH is associated with diffuse white matter damage, even in normal-appearing cerebral white matter. Received: 2 July 1999/Accepted: 13 July 1999     

Proton MR spectroscopy and magnetization transfer ratio in multiple sclerosis: correlative findings of active versus irreversible plaque disease.

PURPOSETo characterize plaques of multiple sclerosis (MS) using both proton MR spectroscopy and magnetization transfer (MT) imaging.METHODSThe magnetization transfer ratio (MTR) was calculated from two series of three-dimensional gradient-recalled acquisition in the steady state (GRASS) images obtained with and without an MT saturation pulse. Proton spectra were acquired using the point-resolved spectroscopy (PRESS) sequence with a voxel size of 1.5 x 1.5 x 1.5 cm3. A total of 28 spectra were obtained in 13 patients who had clinically definitive MS. The spectra were analyzed together with the MTR.RESULTSA positive relationship was found between the N-acetylaspartate (NAA)/creatine (Cr) ratio and the MTR in MS plaques, whereas no significant correlation was found between the metabolite ratios and the signal intensity on fast spin-echo T2-weighted MR images.CONCLUSIONSmall changes in the MTR of MS plaques relative to the MTR of normal white matter may reflect inflammatory changes and edema, whereas larger changes in MTR correlate with decreased NAA/Cr ratio and therefore suggest demyelination and irreversible damage from chronic MS plaques.     

Detection of pyramidal tract lesions in amyotrophic lateral sclerosis with magnetization-transfer measurements.

PURPOSETo determine the presence of small lesions in the pyramidal tract in patients with amyotrophic lateral sclerosis (ALS) by using magnetization-transfer (MT) measurements and MR imaging.METHODSMT ratios (MTRs) were measured in the posterior limb of the internal capsule in nine patients with ALS and in nine healthy volunteers.RESULTSThe mean value of MTRs (%) in patients with ALS was 15.76 +/- 1.48, while that of the control subjects was 19.83 +/- 1.54. The difference was statistically significant.CONCLUSIONSMT measurements are useful for detecting abnormalities associated with degeneration of the pyramidal tract in patients with ALS.     

Magnetisation transfer ratios of contrast-enhancing and nonenhancing lesions in multiple sclerosis

Magnetisation transfer (MT) is a recently introduced technique for assessing the water content of tissues in vivo and its relationship to macromolecules or membranes. It has been suggested that MT could provide indirect evidence of the characteristics of multiple sclerosis (MS) lesions (oedema, demyelination, or gliosis). Our aims were to characterise brain MS lesions and to compare the magnetisation transfer ratio (MTR) values of lesions with different patterns of contrast enhancement. In patients with MS we measured the MTR of 65 gadolinium-enhancing and 292 nonenhancing lesions. Using the equation published by Dousset et al. we studied 29 patients with clinically definite MS and 10 healthy controls. Lesions had significantly lower MT than the normal-appearing white matter of the patients or the normal white matter of healthy controls. There was no difference in the MTR of enhancing and nonenhancing lesions. Enhancement was homogeneous in 45 and ring-like in 20 lesions; MTR values were lower in the latter. These findings are presumably related to the differences in pathological features of enhancing (different amounts of proteins and inflammatory cells, oedema and demyelination) and nonenhancing (gliosis, demyelination and axonal loss) lesions.     

Age-related changes in normal-appearing brain tissue and white matter hyperintensities: more of the same or something else?

BACKGROUND AND PURPOSE: Cerebral white matter (WM) hyperintensities are a frequent finding in elderly people, and lowering of cerebral magnetization transfer ratio (MTR) has been observed. The aim of this study was to assess the relationship between age-related WM hyperintensities and MTR changes in the brain. METHODS: We performed MR imaging in a group of young subjects, a group of elderly individuals with minimal WM hyperintensities, and a group of elderly individuals with abundant WM hyperintensities. In addition, we performed volumetric MTR analysis of the whole brain and of the normal-appearing WM (NAWM) in these groups. RESULTS: Volumetric MTR parameters differed between elderly and young patients. Mean MTR +/- standard error of the mean (SEM) was 34.0% +/- 0.12% in the young, 33.0% +/- 0.08% in the elderly with minimal WM hyperintensities, 32.8% +/- 0.09%) in the group with abundant WM hyperintensities. Peak height (number of voxels +/- SEM) was 122 +/- 1.2 in the young, 99 +/- 1.5 in the elderly with minimal WM hyperintensities, and 98 +/- 1.6 in the group with abundant WM hyperintensities. Mean MTR of NAWM was lower in the elderly compared with the young (36.7% +/- 0.12%) but did not differ between subjects with minimal (36.0% +/- 0.11%) and those with abundant WM hyperintensities (35.9% +/- 0.13%). CONCLUSION: Our results show that aging gives rise to changes in normal-appearing brain tissue. These changes, which can be detected on magnetization transfer imaging, seem to have no relationship with age-related WM hyperintensities and might have a different etiology.     

Adenoidal width and HIV factors.

PURPOSETo determine the factors that correspond to adenoidal hypertrophy, often prominent in human immunodeficiency virus (HIV)-positive patients.METHODSThe sagittal T1-weighted MR images of 21 HIV-positive patients (age range, 25 to 50 years; mean, 37 years) and 21 healthy control subjects (age range, 24 to 55 years; mean, 35 years) were reviewed blindly and independently by two radiologists who measured the maximal dimension of the nasopharyngeal lymphoid tissue. Twenty-six additional HIV-positive patients were combined with the original 21 HIV-positive patients, and the hematologic studies of these 47 patients were compared with the adenoidal measurements to assess whether a relationship existed between nasopharyngeal prominence and hematocrit, white blood cell count, and CD4 count.RESULTSMean adenoidal width was 6.76 mm (SD, 5.82) in the HIV-positive population, but was only 3.36 mm (SD, 2.48) in the age-matched control group. Age and HIV status correlated with nasopharyngeal width measurements. No relationship between adenoidal width and hematocrit, CD4 count, or white blood cell count was evident.CONCLUSIONAfter correcting for age, we found that adenoidal lymphoid tissue is more abundant in HIV-positive persons than in control subjects. The hematologic ramifications of this finding remain uncertain.