Blood oxygen level-dependent MRI for the monitoring of neoadjuvant chemotherapy in breast carcinoma: initial experience.

PURPOSE: To determine the feasibility of using R2* map MRI for pretreatment diagnosis and monitoring of tumor response to neoadjuvant chemotherapy (NAC) in patients with breast cancer. MATERIAL AND METHODS: Twenty-eight women with breast cancer, as evidenced by pathology, underwent MR imaging prior to and after chemotherapy. All patients were examined by conventional MRI and R2* map imaging. Subjects were divided into major histological response (MHR) and non-major histological response (NMHR) groups. Mean R2* values of cancerous and normal glandular tissues were measured before and following NAC. Differences in R2* and ΔR2*% values between these two groups were compared with paired or independent t tests. The relationship between ΔR2*% and histological response was examined using Spearman's correlation test. RESULTS: Before NAC, the average R2* values in carcinoma were lower than in normal glandular tissue (P<.05). After two to four cycles of NAC, the R2* values in carcinoma were increased (P<.05 ), but this change was not significant in normal glandular tissue. After NAC, ΔR2*% was significantly higher in MHR as compared to NMHR (P<.05). The ΔR2*% correlated with the histological response (r=0.581, P<.01). CONCLUSION: In women undergoing NAC for breast cancer treatment, R2* and ΔR2*% appear to provide predictive information of tumor response which is probably associated with changes in tumor angiogenesis and tissue oxygenation. R2* map imaging of breasts may therefore be useful in monitoring tumor response to NAC.

[Small hepatocellular carcinoma in patients with hepatitis B-induced cirrhosis: a comparison between MRI and MDCT].

OBJECTIVE: To compare efficacy of plain and contrast enhancement MRI (1.5T or 3T) and dynamic contrast enhanced multidetector CT (MDCT, 16- or 64 -slice) for the detection of small hepatocellular carcinoma (HCC) in patients with hepatitis B-induced cirrhosis. METHODS: A total of 21 patients (18 men, 3 women; age range, 44-74 years) with 22 small HCC and liver cirrhosis were enrolled, all having undergone MDCT and MRI within one month. The diagnosis of small HCC was established at surgical resection (n=4), percutaneous biopsy (n=1), with positive tumor staining at intervention or from combined clinical data, typical imaging features and follow-up for a period of at least one year. Triple-phase or dual-phase dynamic contrast enhancement was performed on a 16- or 64-slice MDCT. MRI sequences included transverse T1-weighed images acquired as fast spoiled gradient (FSPGR) in-phase and out-of-phase dual-echo, transverse T2-weighed images with respiratory triggering acquired as fat-suppressed fast spin echo (FSE) or fast recovery fast spin echo (FRFSE), and breath-hold coronal T2-weighed images acquired as single shot fast spin echo (SSFSE) or fast imaging employing steady-state acquisition (FIESTA). CT and MRI observers independently analyzed each image in random order and marked each lesion detected with a score, ranking from 1 to 5 (1 definitely benign, 2 possibly benign, 3 undetermined, 4 possible HCC, and 5 definite HCC), then receiver operating characteristic (ROC) curve and Chi-square analysis were adopted to compare the efficacy for MDCT and MRI imaging. RESULTS: Although no significant difference was demonstrated at the comparison of sensitivity and specificity (sensitivity and specificity of MDCT: 70%, 50%; sensitivity and specificity of MRI 86.36%, 100%; sensitivity χ2=0.835, P=0.360; specificity χ2=1.379, P=0.240), the Az (area under the ROC curve) for MRI imaging (mean, 0.974) was much higher than that for MDCT (mean, 0.795) with significant difference (P<0.05). CONCLUSION: MRI imaging shows better diagnostic accuracy for the detection of small HCC in patients with hepatitis B-induced cirrhosis and is recommended to improve the detection and diagnosis.

Comparison of diffusion-weighted with T2-weighted Imaging for detection of small hepatocellular carcinoma in cirrhosis: preliminary quantitative study at 3-T.

RATIONALE AND OBJECTIVES: To compare diffusion-weighted (DW) with standard T2-weighted imaging for quantitative evaluation of small hepatocellular carcinoma (HCC) in cirrhosis. MATERIALS AND METHODS: Fourteen patients (all men; mean age, 58.6 years; age range, 45-69 years) with 22 small HCCs (<3 cm and >1 cm in diameter) in cirrhosis were included in the study. DW imaging with breath-hold single-shot echo planar imaging (b = 0, 800 seconds/mm(2)) and T2-weighted imaging with respiratory triggering fat-suppressed fast spin-echo sequence were performed on a 3-T magnetic resonance unit using an eight-channel torso phased-array coil. The signal intensity (SI) of HCC and liver were measured at workstation. Contrast-to-noise ratio (CNR), contrast ratio (CR, SI(lesion)/SI(liver)), and apparent diffusion coefficient (ADC) values were calculated. CNRs and CRs obtained with DW and T2-weighted images, and ADCs of HCC and liver were compared using nonparametric tests. RESULTS: Two lesions were excluded because of artifacts on DW images. Thus 20 lesions were analyzed. The CNRs obtained with T2-weighted images (27.12 + or - 21.12) were significantly higher (P = .02) than those with DW images (17.52 + or - 13.50). There were no significant difference between the CRs obtained with T2-weighted images (1.83 + or - 0.56) and DW images (2.01 + or - 0.67). There were no significant difference between the mean ADCs of HCC (1.22 x 10(-3) mm(2)/second + or - 0.24) and the cirrhotic liver (1.17 x 10(-3) mm(2)/second + or - 0.17), either. CONCLUSION: DW imaging with high b value was not superior to standard T2-weighted imaging in terms of lesion conspicuity of small HCC in cirrhosis.

Heterogeneity of magnetic resonance imaging in Leigh syndrome with SURF1 gene 604G-->C mutation.

OBJECTIVE: To identify the magnetic resonance (MR) features of a group of pediatric patients with Leigh syndrome (LS) caused by SURF1 gene 604G-->C mutation. MATERIALS AND METHODS: Eight cases with definite diagnosis of SURF1 gene 604G-->C mutation in our hospital were reviewed. Most cases presented typical symptoms in their infancy or childhood, with psychomotor regression, hypotonia, or eye movement disturbances. They all underwent cranial MR examinations after the onset. Their brain images were reviewed by an experienced neuroradiologist to determine the abnormalities. RESULTS: The data of our group showed heterogeneous neuroradiological findings: involvement of the brain stem and subthalamic nuclei was found in only three cases; basal ganglia abnormalities were detected in two cases, whereas demyelination was demonstrated in four cases; and brain atrophy existed invariably in the group. CONCLUSION: The MR presentation in LS patients with SURF1 gene 604G-->C mutation is variable. Maybe it is not appropriate to correlate a specific gene mutation with a homogenous radiological pattern.

CT angiography of pulmonary embolism using a 64 slice multi-detector scanner.

BACKGROUND: Multi-detector computed tomography (MDCT) has already been the first line investigation method for diagnosis of pulmonary embolism (PE). Reducing the amount of contrast medium used during CT scanning could decrease the incidental rate of adverse reactions. Our study amied to evaluate the image quality of pulmonary arteries using 64 slice multi-detector CT with small volumes of contrast media injection. METHODS: Forty nonconsecutive patients without PE or other lung diseases were randomly assigned to two groups. Group A underwent CT scanning with 16 x 1.25 mm collimation and a 70 ml contrast injection, while group B had CT with 64 x 0.625 mm collimation and 20 ml of contrast injection. Two readers independently depicted the segmental and subsegmental pulmonary arteries. Reasons we could not analyze the pulmonary artery or that led to misdiagnosis of pulmonary embolism were evaluated, including the degree of contrast enhancement of the main pulmonary artery, and factors that caused misdiagnosis of PE (flow-related artifacts, partial volume artifact, beam-hardening artifacts and enhancement of pulmonary vein). The independent samples t-test, Mann-Whitney U test and Pearson chi-square test were applied. RESULTS: There were no significant differences in image quality of segmental and subsegmental arteries between the two groups. No significant difference was found for factors that made pulmonary arteries non-analyzable or in the misdiagnosis of PE, except the degree of contrast enhancement. CONCLUSION: 64 x 0.625 mm collimation with 20 ml contrast injection could depict the pulmonary arteries well.

Underdevelopment of optic radiation in children with amblyopia: a tractography study.

PURPOSE: To detect the abnormalities of the optic radiation (OR) in children with amblyopia by diffusion tensor imaging (DTI) and tractography. DESIGN: Prospective, nonrandomized clinical trial. METHODS: Fourteen children with amblyopia and 14 normally sighted children underwent DTI scanning. After the ORs were reconstructed by using tractography algorithm, voxels through which the anterior parts of ORs passed were determined for their values of fractional anisotropy (FA). The paired t test was applied to compare their mean FA values of right OR and left OR in the control group. For the amblyopia group, analysis of variance was conducted to determine the effect of laterality and vision status on the FA values. In addition, the voxel numbers of anterior and posterior parts of both ORs were calculated. The Student t test was used to compare the average FA of bilateral ORs and voxel numbers between the two groups. RESULTS: Comparison demonstrated left-higher-than-right asymmetry in both amblyopic children and normal children. We found no significant difference of average FA between the amblyopic group (0.4832 +/- 0.0225) and control group (0.4770 +/- 0.0273). Voxel numbers of the anterior parts of both ORs were not significantly different between the two groups, whereas voxel numbers of their posterior parts in the controls were more than that of amblyopic children. CONCLUSION: Tractography showed more voxels in the posterior ORs of normal children than in the amblyopic children, indicating that normal children have better development of the ORs. The underdevelopment of the ORs might reflect the dysfunction of visual cortex in children with amblyopia.

Detection of abnormal visual cortex in children with amblyopia by voxel-based morphometry.

PURPOSE: To detect the abnormalities of gray matter in children with amblyopia by voxel-based morphometry (VBM). DESIGN: Prospective, nonrandomized clinical trial. METHODS: Thirteen children with amblyopia and 14 normally sighted children underwent magnetic resonance (MR) examination. The two groups were age-matched with a mean age of 5.8 years. In the amblyopia group, five children had strabismus amblyopia, and eight had anisometropic amblyopia. We analyzed the original 3-dimensional T1 brain images using the VBM module within the widely used analysis software package SPM2 (Welcome Department of Cognitive Neurology, London, United Kingdom). After normalization, segmentation, and smoothing of the images, comparison between amblyopic and control groups was derived for the gray matter of the entire brain using parametric statistics. RESULTS: The results of VBM analysis indicated that the amblyopic group had decreased gray matter density in the middle frontal gyrus, parahippocampal gyrus, fusiform gyrus, inferior temporal gyrus of the left hemisphere, and the bilateral calcarine cortices. The radii of these regions ranged from 12 to 36 voxels. These abnormalities were consistent with morphologic changes in brain regions related to visual function. CONCLUSIONS: Using MR and VBM analysis, we detected morphologic changes in the visual cortex of children with amblyopia, which may indicate developmental abnormalities of visual cortex during the critical growth period.

[Analysis of the clinical information of 1,066 cases undergoing prostate magnetic resonance examination].

OBJECTIVE: To evaluate the variation of clinical data and referred purpose of prostate magnetic resonance (MR) examination in the past 12 years in Peking University First Hospital. METHODS: One thousand and sixty-six patients underwent prostate MR examination (1,296 exams) from May 1992 to Sept. 2004. The clinical data of the patients were retrospectively analyzed. The number of patients was counted and three groups were classified (diagnosing group, staging group and follow-up group) according to the purpose of prostate MR examination per year. For the diagnosing group, the clinical data of patient's age, symptom, level of serum prostate specific antigen (PSA), and the result of ultrasound or digital rectal examination (DRE) were evaluated. RESULTS: (1)The number of patients increased year by year in the past 12 years, and the majority of the increased patients required differential diagnosis. (2) Diagnosing group: the percentage of patients with the symptom of BPH increased year by year. The average level of serum PSA dropped and the percentage of patients with elevated PSA or with nodules detected by ultrasound or DRE referred for detection of prostate cancer or with the symptom of metastasis decreased. CONCLUSION: With the widespread screening of prostate cancer, more patients of early prostate carcinoma and non-tumoral lesion in prostate gland are examined by MR imaging.

[In vivo fluorescent microscopy of the liver microcirculation after embolization with a newly developed trans-proper hepatic arterial infusion animal model].

OBJECTIVE: To evaluate the value of the in vivo fluorescent microscopy in studying the changes of liver microcirculation after embolization with a newly developed animal model for tans-proper hepatic arterial infusion, and to summarize the method of making this animal model. METHODS: Ten Sprague-Dawley rats were used in this study. After a midline abdominal incision, microcatheter was placed into the gastroduodenal artery (GDA). The tip of the catheter was placed facing the orifice of proper hepatic artery. After infusions of 0.02%, 0.1%, 0.5%, 1% fluorescent sodium, fluorescent microscopy was used to evaluate the liver microcirculation. The image quality was then accessed. Embolization was obtained by injections of Lipiodol and Degradable Starch Microspheres (DSM) from the microcatheter. Corresponding changes of the liver microcirculation was evaluated by fluorescent microscopy. RESULTS: From the 10 rats, 8 animal models were successfully established. The microcirculation of the liver could be clearly visualized by the fluorescent microscopy. The optimal concentration of fluorescent sodium was 0.1%. The direct and indirect phenomena caused by embolic material could be evaluated by fluorescent microscopy. CONCLUSION: Fluorescent microscopy with the corresponding Trans-hepatic arterial infusion animal model is a valuable method to evaluate the microcirculation of the liver and can be used for the evaluation of changes of liver microcirculation caused by embolization material.

Evaluation of bilateral cingulum with tractography in patients with Alzheimer's disease.

A fiber-tracking algorithm was used to extract fractional anisotropy of bilateral cingulum bundles in patients with probable Alzheimer's disease and normal aging controls. In addition, their hippocampal volumes were measured manually. Relative to normal controls, Alzheimer's disease patients showed a significant reduction of fractional anisotropy and hippocampal volumes. Significant correlation was observed between fractional anisotropy values and volumes of hippocampi and mini-mental state examination scores. This study suggests that lower anisotropy of cingulum bundles is associated with cognitive dysfunction and atrophy of the limbic system.

Patterns of brain activation in patients with mild Alzheimer's disease during performance of subtraction: an fMRI study.

We performed a functional MRI (fMRI) study to compare the difference of activation between healthy aged people and patients with mild Alzheimer's disease (AD) during performance of subtraction. Nine patients with mild AD and nine healthy aged volunteers were recruited in this study. The analysis of fMRI data revealed that brain activation is decreased in several regions in AD patients in comparison with healthy participants. But in the right inferior prefrontal lobe, activation is greater in patients than in the controls. We believe that our findings will help the understanding mechanism of neuronal activity in AD.