MATERIALS AND METHODS: Twenty-six of 214 patients with aneurysmal SAH were included in the prospective study, approved by the local ethics committee. All patients met the criteria of medically refractory cerebral vasospasm. Effectiveness was monitored angiographically by digital subtraction angiography and by transcranial Doppler (TCD), perfusion CT (PCT), and neurologic examination during treatment course and follow-up.

RESULTS: No angiographic effect was observed in 8 patients. The pooled PCT values revealed a reduction of time to peak (P = .03) and mean transit time (P = .17) 1 day after intervention. This effect did not persist during the following days. The pooled TCD analysis demonstrated a transient increase in flow 1 day after intervention (P = .03). No trend was evident during the next 7 days after intervention. Additional infarction was experienced by 61.1% of patients.

CONCLUSIONS: IAN in a selective patient group resulted in a positive response with reduction of angiographic vasospasm and increase in cerebral perfusion as detected by PCT after 24 hours. Therefore, IAN appears more effective than intra-arterial papaverine. Nevertheless the efficacy of IAN is temporary. Therefore, the search for more effective treatment strategies to reduce critical vasospasm and to improve cerebral perfusion must be continued.

MATERIALS AND METHODS: A total of 29 patients eligible for IV rtPA, who were diagnosed as having MCA (M1 or M2) occlusion within 3 hours of onset, underwent thrombolysis. In the combined group, patients were treated by IV rtPA (0.6 mg/kg for 60 minutes) and simultaneous ET (intra-arterial rtPA, mechanical thrombus disruption with microguidewire, and balloon angioplasty) initiated as soon as possible. In the IV group, patients were treated by IV rtPA only.

RESULTS: The improvement of the National Institutes of Health Stroke Scale (NIHSS) score at 24 hours was 11 ± 4.8 in the combined group versus 5 ± 4.3 in the IV group (P < .001). In the combined group, successful recanalization was observed in 14 (88%) of 16 patients with no symptomatic intracranial hemorrhage, and 10 (63%) of 16 patients had favorable outcomes (modified Rankin Scale [mRS] 0, 1) at 3 months.

CONCLUSIONS: Aggressive combined therapy with IV rtPA and simultaneous ET markedly improved the clinical outcome of hyperacute MCA occlusion without significant adverse effect. Additional randomized study is needed to confirm our results.

MATERIALS AND METHODS: Serial digital subtraction angiography was performed in 5 bifurcation aneurysms 1, 4, 7, and 10 months after surgical creation. Aneurysm dimensions, including height, width, and neck diameter, and animal body weights were measured. Comparisons of each parameter were performed using the Friedman test and the paired Wilcoxon signed-rank test.

RESULTS: Four of 5 aneurysms were patent during a 10-month follow-up period. One aneurysm was regarded as a partially thrombosed aneurysm at 1 month, though the extent of partial thrombosis lessened at 10 months. Bifurcation aneurysms progressively increased in size (aneurysm height, width, and neck diameter) during the first several months.

CONCLUSION: If this experimental model is used to evaluate new endovascular devices for cerebral aneurysm treatment, investigators should be aware of early progressive aneurysm enlargement.

MATERIALS AND METHODS: We scanned an agar gel phantom with a cobalt-alloy clip mounted in the center by using subtraction CT with and without OSHST. Eighteen patients (20 aneurysms) who underwent surgery with cobalt-alloy clips were postoperatively evaluated with subtraction CTA with OSHST, and the results were compared with those from digital subtraction angiography. Two neuroradiologists independently evaluated the 3D CTA images and source images with and without subtraction for the presence of residual flow in the aneurysm and stenotic change in parent or neighboring arteries.

RESULTS: For the phantom study, significantly fewer artifacts from clips were noted on images obtained by using subtraction CT with OSHST than on those obtained without OSHST. For the clinical study, subtraction CTA with OSHST also showed fewer clip artifacts than did conventional CTA. Image quality was poor, and we were unable to diagnose residual neck for 5% (1/20) with subtraction CTA with OSHST and 75% (15/20) with conventional CTA. For evaluation of adjacent vessels, image quality was poor for none (0/20) with subtraction CTA with OSHST and for 55% (11/20) with conventional CTA. For subtraction CTA with OSHST, sensitivity in detecting residual neck was 1.0, and specificity was 0.94. For conventional CTA, sensitivity and specificity were both 0.25.

CONCLUSIONS: OSHST is a useful technique for subtracting cobalt-alloy clips, and subtraction CTA with OSHST is available for evaluating aneurysms after clipping with cobalt-alloy clips.

MATERIALS AND METHODS: This study was approved by all of the 6 institutional review boards, and all of the patients gave informed consent. This study included a total of 103 consecutive neuroembolizations in the 6 institutions. Patient ESDs during the procedures were evaluated by using caps that had 44 radiosensitive indicators adherent to the surface. The patient ESDs were calculated from the color difference of the indicators. To check for effects on the scalp, clinical follow-up was performed at 1-2 days, 2 weeks, and 3 months after the procedure.

RESULTS: The averages of total fluoroscopic time, total number of digital subtraction angiography frames, and dose area product were 67.1 ± 41.6 minutes, 883 ± 626, and 257 ± 150 Gy x cm², respectively. The average maximum ESD for each patient was 1.9 ± 1.1 Gy (range, 0.4–5.6 Gy; median, 1.5 Gy). The average maximum ESDs of each institution ranged from 1.0 to 2.4 Gy. Epilation was observed in 6 patients.

CONCLUSIONS: The maximum ESDs during neuroembolizations exceed the thresholds for radiation skin injuries in some cases.

MATERIALS AND METHODS: Birth history, delivery method, duration of each stage of labor, pharmaceutic augmentation, and complications during delivery as well as postnatal physical examination were recorded. Brain MR imaging and US were performed on 101 asymptomatic term infants at 3–7 days, 2 weeks, 1 month, and 3 months. Clinical follow-up at 24 months was recorded.

RESULTS: Forty-six neonates had SDH by MR imaging within 72 hours of delivery. SDH was seen in both vaginal and cesarean deliveries. All neonates were asymptomatic, with normal findings on physical examination. All 46 had supratentorial SDH seen in the posterior cranium. Twenty (43%) also had infratentorial SDH. US detected 11 of the 20 (55%) infratentorial SDHs and no supratentorial SDH. Most SDHs present at birth were ≤3 mm and had resolved by 1 month, and all resolved by 3 months on MR imaging. Most children with SDHs had normal findings on developmental examinations at 24 months.

CONCLUSION: SDH in asymptomatic term neonates after delivery is limited in size and location.

MATERIALS AND METHODS: A total of 246 patients with acute (<3 weeks) low back pain (LBP) and/or radiculopathy (150 LBP and 96 radiculopathy patients) were recruited. Patients were randomized using a stratified block design with equal allocation to either the unblinded group (MR imaging results provided within 48 hours) or the blinded group (both patient and physician blinded to MR imaging results.) After the initial MR imaging, patients followed 6 weeks of conservative management. Roland function, visual pain analog, absenteeism, Short Form (SF)-36 Health Status Survey, self-efficacy scores, and Fear Avoidance Questionnaire were completed at presentation; 2, 4, 6, and 8 weeks; and 6, 12, and 24 months. Improvement of Roland score by 50% or more and patient satisfaction assessed by Cherkin symptom satisfaction measure were considered a positive outcome.

RESULTS: Clinical outcome at 6 weeks was similar for unblinded and blinded patients. Self-efficacy, fear avoidance beliefs, and the SF-36 subscales were similar over time for blinded and unblinded patients, except for the general health subscale on the SF-36. General health of the blinded group improved more than for the unblinded group (P = .008).

CONCLUSIONS: Patient knowledge of imaging findings do not alter outcome and are associated with a lesser sense of well-being.

MATERIALS AND METHODS: From September 2000 to August 2007, 7 patients were selected from our data base of 214 patients with confirmed vertebral osteomyelitis and MR images. All of those having misinterpreted MR imaging reports and unusual imaging patterns were analyzed. The presence of a peripheral curvilinear area of low signal intensity in an osseous lesion (the rim sign) and a peripheral rim of high signal intensity on T2-weighted images around an osseous lesion (the halo sign) was evaluated. Follow-up MR imaging studies were performed in all patients.

RESULTS: The patients were 5 men and 2 women, with an age range of 42–80 years. MR imaging findings of those with vertebral osteomyelitis showed a solitary lesion in 2 and multiple lesions in 5 patients. The intraosseous lesions revealed low signal intensity on T1-weighted images, mixed or high signal intensity on T2-weighted images, high signal intensity on short inversion recovery images, and global or marginal enhancement. The rim sign was found in 6 (86%) patients; halo sign, in 7 (100%); preserved intervertebral disks, in 7 (100%); and limited paraspinal or epidural inflammation, in 6 (86%). Images of all patients demonstrated healing or almost healed changes on the follow-up MR imaging studies.

CONCLUSION: Vertebral osteomyelitis can have MR imaging patterns mimicking osseous metastases. Recognition of these unusual imaging manifestations, together with clinical and histopathologic analysis, may aid in reaching the correct diagnosis.

MATERIALS AND METHODS: Of 230 prospectively screened, consecutive patients with acute ischemic stroke, 87 had noncontrast CT (NCCT)/CT angiography (CTA), and 118 had MR imaging/MR angiography (MRA) at admission and were classified as having major stroke by BASIS criteria if they had a proximal cerebral artery occlusion or, if no occlusion, imaging evidence of significant parenchymal ischemia; all of the others were classified as minor strokes. Outcomes included death, length of hospitalization, and discharge disposition. BASIS was compared with ASPECTS (dichotomized > or ≤7) in 87 patients who had NCCT/CTA.

RESULTS: BASIS classification by NCCT/CTA was equivalent to MR imaging/MRA. Fifty-six of 205 patients were classified as having major strokes including all 6 of the deaths. A total of 71.4% and 15.4% of major and minor stroke survivors, respectively, were discharged to a rehabilitation facility, whereas 14.3% and 79.2% of patients with major and minor strokes were discharged to home. The mean length of hospitalization was 12.3 and 3.3 days for the major and minor stroke groups, respectively (all outcomes, P < .0001). In 87 NCCT/CTA patients, BASIS and ASPECTS agreed in 22 major and 44 minor strokes. BASIS classified 21 patients as having major strokes who were classified as having minor strokes by ASPECTS. The BASIS major/ASPECTS minor stroke group had outcomes similar to those classified as major strokes by both instruments.

CONCLUSIONS: The BASIS classification instrument is effective and appears superior to ASPECTS in predicting outcomes in acute ischemic stroke.

MATERIALS AND METHODS: Forty-four patients receiving intravenous rtPA and 19 controls underwent CT perfusion (CTP) studies in the emergency department within 3 hours of stroke onset. Lesion volumes were measured on MTT, CBV, and CBF maps by region-of-interest analysis and were compared with follow-up CT volumes by correlation and regression analysis. The volume of salvaged tissue was determined as the difference between the initial MTT and follow-up CT lesion volumes and was compared between intravenous rtPA-treated patients and controls.

RESULTS: No significant difference between the groups was observed in lesion volume assessed from the CTP maps (P > .08). Coefficients of determination for MTT, CBF, and CBV versus follow-up CT lesion volumes were 0.3, 0.3, 0.47, with intravenous rtPA; and 0.53, 0.55, and 0.81 without intravenous rtPA. Regression of MTT on CBF lesion volumes showed codependence (R² = 0.98, P < .0001). Mean salvaged tissue volumes with intravenous rtPA were 21.8 ± 17.1 and 13.2 ± 13.5 mL in controls; these were significantly different by using nonparametric (P < .03) and Fisher exact tests (P < .04).

CONCLUSIONS: Within 3 hours of stroke onset, CBV lesion volume does not necessarily represent dead tissue. MTT lesion volume alone can be used to identify the upper limit of the size of abnormally perfused brain. More brain is salvaged in patients with intravenous rtPA than in controls.

MATERIALS AND METHODS: The subject group consisted of 5 healthy control subjects and 7 study subjects (all males; 16–19 years old; mean age = 17.5 years), as part of a protocol for closed head injury. Two whole-brain DTI scans were acquired on a 3T scanner for each subject. Analysis was performed using a ROI approach. Two independent observers analyzed the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) indices in the corpus callosum, cortical spinal tract, internal capsules (ICs), basal ganglia, and centrum semiovale (CSO). Intraobserver and interobserver variability were calculated for the mean ADC, FA, and ordered eigenvalues of the diffusion tensor (₁, ₂, and ₃).

RESULTS: The overall statistic for intraobserver variability for both observers showed slight-to-substantial agreement ( = 0.02–0.69), however FA values in the CSO showed only slight agreement. Interobserver agreement was also slight to substantial for these DTI measurements with high variability in FA values in the IC and CSO.

CONCLUSIONS: When one is comparing 2 DTI measurements, it is important to assess intraobserver and interobserver variability. We recommend caution in the analysis of DTI contrasts in the IC and CSO, because we have found the widest range of variability in measurements within these structures.

MATERIALS AND METHODS: Twelve healthy volunteers underwent MR imaging twice. MR imaging was performed on a 3T unit, and FA maps were analyzed independently by 2 observers using ROIs positioned in the corpus callosum, internal capsules, corticospinal tracts, and right thalamus. Changes in FA values (x10³) measured with 2 b-values (700 and 1000 s/mm²), age-related differences, interobserver agreement, and measurement reproducibility were assessed.

RESULTS: In the right internal capsule genu (FA = 702/728; b = 1000/700 s/mm²) and the left anterior limb of the internal capsule (AIC; FA = 617/745; b = 1000/700 s/mm²), the FA values were significantly different between the 2 b-values (P = .02 and .05, respectively). Significant age-related differences in FA were observed in the genu of the corpus callosum and in the left AIC. Interrater measurements showed fair-to-moderate agreement for most anatomic structures. The lowest significant change for a single subject regarding any FA values between the 2 sessions was in the corpus callosum (4%), whereas the highest one was in the corticospinal tracts (27%). The Bland-Altman plot analysis showed that the 1000-s/mm² b-value gave satisfactorily reproducible measurements equally good or better than the 700-s/mm² b-value.

CONCLUSION: The reproducibility of FA estimates using ROIs was satisfactory. Measurements with a b-value at 1000 s/mm² showed superior reproducibility in most anatomic locations.

MATERIALS AND METHODS: Diffusion tensor imaging (DTI) scans were acquired from 7 healthy adult normal readers and from 14 adults with dyslexia on a 1.5T scanner. Voxelwise statistical analysis of the fractional anisotropy data were carried out by using Tract-Based Spatial Statistics to compare dyslexic subjects versus control subjects in white matter tracts.

RESULTS: Significant group difference map clusters (comparing adults with and without dyslexia) occurred in specific bilateral white matter tracts within the frontal lobe, temporal lobe, occipital lobe, and parietal lobe.

CONCLUSION: The DTI fractional anisotropy results in the bilateral white matter showing higher fractional anisotropy in adult control subjects compared with adults with dyslexia (relating to white matter fiber tract integrity) are consistent with our previous functional connectivity results from seed points in the bilateral inferior frontal gyrus.

MATERIALS AND METHODS: Two staff and 2 fellow neuroradiologists reviewed 75 brain CT scans obtained within 3 hours of acute ischemia from subjects in the Interventional Management of Stroke Study. Films were reviewed 3 months apart, the first time with tape over the eyes on the images, the second with the eyes visible. Readers were asked if early hypoattenuation in the middle cerebral artery (MCA) distribution or if a hyperattenuated MCA was present. statistics were calculated to determine agreement among the 4 readers and between each of the 2 readings by the same reader, not only for the original interpretation of the blinded study neuroradiologist but also for the Alberta Stroke Program Early CT Score (ASPECTS) for each subject assigned by an unblinded expert panel. A generalized estimating equations modeling approach was used to look at the overall effect of including eye information for agreement between interpretations.

RESULTS: Eye information availability was associated with improved agreement for detection of early ischemic hypoattenuation not only among the 4 readers but also between the 4 readers and both the blinded study neuroradiologist (P = .02) and the unblinded expert ASPECTS panel. When comparing first and second readings for hypoattenuation, we also noted increased mean values for sensitivity (46.8% first, 56.5% second), specificity (78.2%, 80.2%), positive predictive value (72.0%, 80.7%), negative predictive value (55.5%, 61.0%), and percentage agreement (61.0%, 67.5%).

CONCLUSION: Observation of CT eye deviation significantly improves reader identification of acute ischemic hypoattenuation.

MATERIALS AND METHODS: We retrospectively compared conventional and DW MR images (b-value 1000 s/mm²) acquired on a 1.5T clinical scanner between 25 atypical/malignant and 23 benign meningiomas. The optimal cutoff for the absolute apparent diffusion coefficient (ADC) and normalized ADC (NADC) ratio to differentiate between the groups was determined by using receiver operating characteristic (ROC) analysis.

RESULTS: Irregular tumor margins, peritumoral edema, and adjacent bone destruction occurred significantly more often in atypical/malignant than in benign meningiomas. The mean ADC of atypical/malignant meningiomas (0.66 ± 0.13 x 10^–3 mm²/s) was significantly lower compared with benign meningiomas (0.88 ± 0.08 x 10^–3 mm²/s; P < .0001). Mean NADC ratio in the atypical/malignant group (0.91 ± 0.18) was also significantly lower than the benign group (1.28 ± 0.11; P < .0001), without overlap between groups. ROC analysis showed that ADC and NADC thresholds of 0.80 x 10^–3 mm²/s and 0.99, respectively, had the best accuracy: at the NADC threshold of 0.99, the sensitivity and specificity were 96% and 100%, respectively. Two patients had isointense benign tumors on initial DW MR imaging, and these became hyperintense with the decrease in ADC and NADC below these thresholds when they progressed to atypical and malignant meningiomas on recurrence.

CONCLUSIONS: ADC and NADC ratios in atypical/malignant meningiomas are significantly lower than in benign tumors. Decrease in ADC and NADC on follow-up imaging may suggest dedifferentiation to higher tumor grade.

MATERIALS AND METHODS: We collected MR images of 126 patients with intra-axial cerebral tumors (58 high-grade gliomas, 37 low-grade gliomas, 19 metastatic tumors, and 12 malignant lymphomas). We constructed a single 3-layer feed-forward ANN with a Levenberg-Marquardt algorithm. The ANN was designed to differentiate among 4 categories of tumors (high-grade gliomas, low-grade gliomas, metastases, and malignant lymphomas) with use of 2 clinical parameters and 13 radiologic findings in MR images. Subjective ratings for the 13 radiologic findings were provided independently by 2 attending radiologists. All 126 cases were used for training and testing of the ANN based on a leave-one-out-by-case method. In the observer test, MR images were viewed by 9 radiologists, first without and then with ANN outputs. Each radiologist's performance was evaluated through a receiver operating characteristic (ROC) analysis on a continuous rating scale.

RESULTS: The averaged area under the ROC curve for ANN alone was 0.949. The diagnostic performance of the 9 radiologists increased from 0.899 to 0.946 (P < .001) when they used ANN outputs.

CONCLUSIONS: The ANN can provide useful output as a second opinion to improve radiologists' diagnostic performance in the differential diagnosis of intra-axial cerebral tumors seen on MR imaging.

MATERIALS AND METHODS: Twenty-six patients with unilateral CSDH underwent DTI before and after surgery. We measured fractional anisotropy (FA) values in pyramidal tracts of bilateral cerebral peduncles and calculated the ratio of the FA value on the lesion side to that on the contralateral side (FA ratio) and compared the ratios with motor weakness. Moreover, the relationships between FA ratios and clinical factors such as age, sex, midline shift, interval from trauma, and hematoma attenuation on CT were evaluated.

RESULTS: FA values of pyramidal tracts on the lesion side were significantly lower than those on the contralateral side (0.66 ± 0.07 versus 0.74 ± 0.05, P < .0001). The FA ratio was correlated to the severity of motor weakness (r² = 0.32, P = .002). FA ratios after surgery improved significantly compared with those before surgery (0.96 ± 0.08 versus 0.89 ± 0.07, P = .0004). Intervals from trauma and the midline shift were significantly associated with decreased FA ratios (P = .0008 and P = .037).

CONCLUSIONS: In patients with CSDH, a reversible decrease of FA in the affected pyramidal tract on DTI was correlated to motor weakness. These anisotropic changes were considered to be caused by a reversible distortion of neuron fibers and vasogenic edema due to the hematoma.

MATERIALS AND METHODS: Eight patients were treated under clinical diagnoses of SIH. Chronologic MR imaging studies, including the FLAIR sequence, were retrospectively reviewed.

RESULTS: Initial MR imaging showed diffuse pachymeningeal thickening as isointense in 6 cases, hypoisointense in 1 case, and isohyperintense in 1 case on the T1-weighted MR images, and hyperintense in all cases on both T2-weighted and FLAIR MR images. Dural (pachymeningeal) hyperintensity on FLAIR MR imaging had the highest contrast to CSF, and was observed as linear in all patients, usually located in the supratentorial convexity and also parallel to the falx, the dura of the posterior fossa convexity, and the tentorium, and improved after treatment. These characteristics of diffuse pachymeningeal hyperintensity on FLAIR MR imaging were similar to diffuse pachymeningeal enhancement (DPME) on T1-weighted imaging with gadolinium. Initial FLAIR imaging clearly showed subdural effusion/hematomas in 6 of 8 patients. The thickness of subdural effusion/hematomas sometimes increased transiently after successful treatment and resolution of clinical symptoms.

CONCLUSION: Diffuse pachymeningeal hyperintensity on FLAIR MR imaging is a similar sign to DPME for the diagnosis of SIH but does not require injection of contrast medium. FLAIR is useful sequence for the detection of subdural effusion/hematomas in patients with SIH.

MATERIALS AND METHODS: All studies were performed at 3T MR imaging. First, the TE for the phase-weighted image was optimized; the best contrast between the motor and other cortices was obtained with a TE of 40 ms. The study population consisted of 45 healthy subjects (23 females, 22 males; mean age, 32.1 years). The signal intensity of the motor cortices was divided into 3 grades by 2 neuroradiologists in comparison with that of the superior frontal cortex (SFC): In grade I, the motor cortex was isointense to the SFC; in grade II, the motor cortex was slightly hypointense to the SFC; and in grade III, the motor cortex was markedly hypointense to the SFC.

RESULTS: The motor cortex was classified as either grade II or III in all subjects older than 20 years of age on the phase-weighted images. Even at 10–19 years of age, the grade II or III appearance was found in 14 (88%) of 16 motor cortices (8 subjects) on the phase-weighted images.

CONCLUSION: In adolescents, the motor cortex is hypointense to other cerebral cortices on phase-weighted MR imaging, which probably reflects differences in the concentration of nonheme iron and/or in the tissue architecture.

MATERIALS AND METHODS: PET examinations were performed for 95 primary gliomas (37 grade II, 37 grade III, and 21 grade IV). We measured the tumor/normal brain uptake ratio (T/N ratio) on each PET and investigated the correlations among the tracer uptake, tumor grade, tumor type, and tumor proliferation activity. In addition, we compared the ease of visual evaluation for tumor detection.

RESULTS: All 3 of the tracers showed positive correlations with astrocytic tumor (AT) grades (II/IV and III/IV). The MET T/N ratio of oligodendroglial tumors (OTs) was significantly higher than that of ATs of the same grade. The CHO T/N ratio showed a significant positive correlation with histopathologic grade in OTs. Tumor grade and type influenced MET uptake only. MET T/N ratios of more than 2.0 were seen in 87% of all of the gliomas. All of the tracers showed significantly positive correlations with Mib-1 labeling index in ATs but not in OTs and oligoastrocytic tumors.

CONCLUSION: MET PET appears to be useful in evaluating grade, type, and proliferative activity of ATs. CHO PET may be useful in evaluating the potential malignancy of OTs. In terms of visual evaluation of tumor localization, MET PET is superior to FDG and CHO PET in all of the gliomas, due to its straightforward detection of "hot lesions".

MATERIALS AND METHODS: Hippocampal volume and cortical thickness were estimated by MR imaging and compared for patients with MCI (n = 18) and healthy controls (n = 18). In addition, regions of interest (ROIs) were selected in areas where the MCI group had atrophy and which overlapped with the episodic memory network (temporal, entorhinal, inferior parietal, precuneus/posterior cingulate, and frontal). Relationships among morphometry, CSF biomarkers, APOE, and memory were tested. The analyses were repeated with an independent sample of patients with MCI (n = 19).

RESULTS: Patients with MCI and pathologic CSF values had hippocampal atrophy. However, both patients with pathologic and patients with nonpathologic CSF had a thinner cortex outside the hippocampal area. CSF pathology was related to hippocampal volume, whereas relationships with cortical thickness were found mainly in one of the samples. Morphometry correlated robustly with memory performance across MCI samples, whereas less stable results were found for tau protein.

CONCLUSION: The differences in hippocampal volume between the MCI and the healthy control groups were only found in patients with pathologic CSF biomarkers, whereas differences in cortical thickness were also found for patients without such pathologic features. Morphometry in areas in the episodic memory network was robustly correlated with memory performance. It is speculated that atrophy in these areas may be associated with the memory problems seen in MCI.

MATERIALS AND METHODS: In this retrospective study, brain and spinal cord MR imaging studies of 11 patients with AOAD (7 men, 4 women; age range, 26–64 years; mean age, 43.6 years), all but 1 genetically confirmed, were reviewed. Diffusion and spectroscopic investigations were available in 6 patients each.

RESULTS: Atrophy and changes in signal intensity in the medulla oblongata and upper cervical spinal cord were present in 11 of 11 cases and were the diagnostic features of AOAD. Minimal to moderate supratentorial periventricular abnormalities were seen in 8 patients but were absent in the 3 oldest patients. In these patients, postcontrast enhancement was also absent. Mean diffusivity was not altered except in abnormal white matter (WM). Increase in myo-inositol (mIns) was also restricted to abnormal periventricular WM.

CONCLUSIONS: Awareness of the MR pattern described allows an effective selection of the patients who need genetic investigations for the GFAP gene. This MR pattern even led to identification of asymptomatic cases and should be regarded as highly characteristic of AOAD.

MATERIALS AND METHODS: Of 6859 patients with vascular diseases who underwent duplex carotid ultrasonography, we studied 512 internal carotid arteries in 441 patients who had a maximum area stenosis at or more than 70%, which corresponds with approximately 50% or more by the NASCET method. The maximal (A) and minimal wall thicknesses (B) were measured on cross-sectional sonography images, and an eccentricity index was calculated using the following formula: (A – B)/A. Arteries in the lowest quartile of the eccentricity index (<0.69) were defined as having a concentric stenosis, whereas the others were defined as having eccentric stenosis. The underlying clinical characteristics and plaque morphologies, as well as the occurrence of ipsilateral ischemic stroke or transient ischemic attack in the preceding year, were compared between patients with eccentric and concentric stenosis.

RESULTS: Patient characteristics and plaque morphology were similar between the 2 groups. Cerebrovascular events occurred more frequently ipsilaterally to the artery with eccentric stenosis (13.5%) than to the artery with concentric stenosis (5.5%; P = .013); the difference was more evident when cerebrovascular events of presumed carotid arterial origin were assessed (P = .005). After adjusting for risk factors and plaque morphology, eccentric stenosis was independently related to the presence of recent cerebrovascular events (odds ratio = 2.76; 95% confidence interval = 1.19–6.40).

CONCLUSIONS: In patients with an area carotid stenosis of 70% or more, eccentric plaque was associated with a significantly increased incidence of ipsilateral cerebrovascular events compared with patients with concentric stenosis.

MATERIALS AND METHODS: CT (n = 11) and MR (n = 10) images of 12 patients (9 men and 3 women; mean age, 41 years; range, 12–76 years) with pathologically proved sinonasal OH were retrospectively reviewed. Particular attention was put on the location, shape, size, extent, internal architecture, and enhancement pattern of the lesion and associated sinus wall change.

RESULTS: The lesions were seen as an expansile (n = 9) or nonexpansile (n = 3) mass, ranging in size from 2.2 to 6.0 cm (mean, 4.2 cm), primarily involving the maxillary sinus (n = 11) or nasal cavity (n = 1) unilaterally. The ipsilateral nasal cavity was also involved in 9 of 11 maxillary sinus lesions. Smooth sinus wall erosion other than the medial maxillary sinus wall was noted in 8 lesions. The internal architecture was best displayed on T2-weighted MR images on which all of the lesions were seen as a mixture of marked heterogeneous hypointensity and isointensity, surrounded by a hypointense peripheral rim, reflecting histologic heterogeneity of the lesion composed of hemorrhage, fibrosis, and neovascularization. Marked irregular nodular, papillary, or frondlike enhancement at the areas of neovascularization was also a typical finding seen in all of the lesions.

CONCLUSION: An expansile soft tissue mass, smooth sinus wall erosion, marked heterogeneous signal intensity with a hypointense peripheral rim on T2-weighted MR images, and marked irregular nodular, papillary, or frondlike enhancement are characteristic CT and MR imaging findings of sinonasal OH.

MATERIALS AND METHODS: The MR imaging reports of patients undergoing imaging after radiation therapy for nasopharyngeal carcinoma were reviewed retrospectively to identify patients with unusual polyps and masses in the nasopharynx. The MR images of those patients with no evidence of malignancy on biopsy or follow-up were reviewed.

RESULTS: The MR imaging reports of 1282 patients were reviewed, and 11 patients (1%) with NMPMs in the nasopharynx or sphenoid sinus were identified. Two patterns were identified: contrast enhancing nasopharyngeal polyps ranging in size from 1 to 5 cm (n = 5) and sphenoid sinus masses consisting of a nonenhancing mass filling a nonexpanded sinus (n = 4) and a heterogeneous enhancing mass expanding the sinus (n = 2). Osteoradionecrosis produced a large defect in the roof of the nasopharynx causing direct communication with the sphenoid sinus (n = 6). Histology revealed granulation tissue in all of the patients with variable amounts of fibrin and inflammatory cells. A direct infective etiology was not proved in any patient.

CONCLUSION: NMPMs in the nasopharynx and sphenoid sinus are rare complications after radiation therapy to the skull base, but the radiologist needs to be aware of their appearance so that they can be considered in the differential diagnosis of suspected tumor recurrence.

MATERIALS AND METHODS: A prospective study of 200 consecutive CT scans in the coronal and axial planes was performed on patients without a history of recent trauma. The images were interpreted independently by a radiologist and an otolaryngologist. The CT studies were evaluated for the presence of a central intersinus septal air cell. If such a cell was identified, it was further classified as either being completely isolated from both frontal sinuses by a bony rim or as a communicating diverticulum from one of the frontal sinuses. If a central cell was present, it was also assessed for how much of the height of the intersinus septum it involved (lower one-half or full height).

RESULTS: There was a complete concordance of the results between the 2 observers. An intersinus septal air cell was seen in 61 (30.5%) of the 200 cases, and 85.3% of these cells were clearly seen to communicate anteromedially with either one of the frontal sinuses or both frontal sinuses (3 cases). In 9 (4.5%) of the 200 cases, the central cell had no demonstrable connection to either frontal sinus. Of the 61 cases with a central cell, 55 (90.16%) of the cells occupied the full height of the septum, and 6 (9.84%) only involved the lower half of the septum.

CONCLUSION: Contrary to the present convention that frontal intersinus septal cells originate as displaced ethmoid cells from the frontal recess, we found that most such cells are actually diverticula from the frontal sinuses themselves.

MATERIALS AND METHODS: From January 1, 2005, through May 22, 2005, a total of 702 CT examinations of the cervical spine or soft tissue of the neck were reviewed. All examinations were at 2- to 5-mm thickness. Sagittal and coronal reconstructions were available for review, if necessary. Paratracheal air cysts were evaluated for size; the presence of visible communication with the trachea; association with pneumothorax, pneumomediastinum, or subcutaneous emphysema; and association with findings of emphysematous changes in the lung apices. Patient demographics of age, sex, and whether the patient had sustained a traumatic injury were also collected.

RESULTS: Of the 702 patients evaluated, 26 (3.7%) had paratracheal air cysts, all of which were found on the right, at the level of the thoracic inlet. Ages of the patients ranged from 15 to 74 years. In 9 (34.6%) of the patients, a direct communication with the trachea was seen. Sizes of the paratracheal air cysts ranged from 1 x 2 mm to 10 x 15 mm. No association was found with CT findings of emphysema in the lung apices, abnormal soft tissue air, or trauma.

CONCLUSION: Right paratracheal air cysts are a common CT finding that occur in a predictable location. In the setting of trauma, these characteristic structures can mimic pneumomediastinum and are seen in approximately 3% to 4% of the US population. The cause is unclear but may be either congenital or an acquired phenomenon, given that they are often seen in both children and adults. We found no association with either trauma or the presence of emphysematous changes in the lung apices.