Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “imaging”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 523 records · Page 29Linked to original sources
PubMed2005

High correlation of whole-body red fluorescent protein imaging and magnetic resonance imaging on an orthotopic model of pancreatic cancer.

We have developed genetically fluorescent orthotopic models of human pancreatic cancer. In these models, noninvasive fluorescent protein imaging (FPI) of internal primary tumors and metastatic deposits has been carried out. Whole-body tumor images are easily and inexpensively obtained using FPI, permitting both detection and quantification of tumor load. In this study, we simultaneously compared single mice with a highly fluorescent, red fluorescent protein-expressing orthotopic pancreatic cancer xenografts with both FPI and high-resolution magnetic resonance imaging (MRI). Images were acquired at multiple time points after tumor implantation in the pancreas. Indwelling pancreatic primary tumors and metastatic foci were detected by both FPI and MRI. Moreover, a strong correlation existed between images taken with these two technologies. FPI permitted rapid, high-throughput imaging without the need for either anesthesia or contrast agents. Both FPI and MRI enabled accurate imaging of tumor growth and metastasis, although MRI enabled tissue structure to be visualized as well. FPI has high resolution and is exceedingly rapid with instant image capture. We suggest a complimentary role for these two imaging modalities.

Animals↗
PubMed2001

Computerized image analysis as a tool to quantify infiltrating leukocytes: a comparison between high- and low-magnification images.

The purpose of the present study was to establish a rapid and reproducible method for quantification of tissue-infiltrating leukocytes using computerized image analysis. To achieve this, the staining procedure, the image acquisition, and the image analysis method were optimized. Because of the adaptive features of the human eye, computerized image analysis is more sensitive to variations in staining compared with manual image analysis. To minimize variations in staining, an automated immunostainer was used. With a digital scanner camera, low-magnification images could be sampled at high resolution, thus making it possible to analyze larger tissue sections. Image analysis was performed by color thresholding of the digital images based on values of hue, saturation, and intensity color mode, which we consider superior to the red, green, and blue color mode for analysis of most histological stains. To evaluate the method, we compared computerized analysis of images with a x100 or a x12.5 magnification to assess leukocytes infiltrating rat brain tumors after peripheral immunizations with tumor cells genetically modified to express rat interferon-gamma (IFN-gamma) or medium controls. The results generated by both methods correlated well and did not show any significant differences. The method allows efficient and reproducible processing of large tissue sections that is less time-consuming than conventional methods and can be performed with standard equipment and software.(J Histochem Cytochem 49:1073-1079, 2001)

Animals↗
PubMed1992

Image comparison techniques for use with megavoltage imaging systems.

In this paper we describe software facilities for enabling patient positioning studies using the megavoltage imaging system developed at the Royal Marsden Hospital and Institute of Cancer Research. The study focuses on the use of the system for three purposes: patient position verification (by comparing images taken at treatment simulation with megavoltage images taken at treatment time); reproducibility studies (by analysing a set of megavoltage images); and set-up correction (by adjusting the set-up until the megavoltage image obtained at treatment registers with the simulation image). The need is discussed for suitably presented simulator images, a method of determining field boundaries and the possibility of delineating soft-tissue interfaces. Several algorithms of different types, developed specifically for the purpose of intercomparison of planar projection images, are presented. The techniques employed and their usefulness, in both the qualitative and the quantitative sense, are discussed. The results are presented of a phantom and clinical study, to evaluate the rigour and reproducibility of the algorithms. These results indicate that measurements can be made to an accuracy of about 1-2 mm, with a similar value for interobserver reproducibility for the best image comparison techniques available.

Algorithms↗
PubMed2004

A new technique for endobronchial ultrasonography and comparison of two ultrasonic probes: analysis with a plot profile of the image analysis software NIH Image.

STUDY OBJECTIVES: Endobronchial ultrasonography (EBUS) is currently the sole clinical method available for delineating the bronchial wall structure; however, the image resolution is inadequate. Thus, an improved image analysis system is needed for both a more accurate and more readily interpretable endobronchial ultrasonogram. MATERIALS AND METHODS: A total of 10 patients underwent pulmonary resection for lung cancer. EBUS was performed on the bronchi of the resected lungs, which had been immersed in physiologic saline solution. The same bronchial lesion in each specimen was imaged with two probes: 20 MHz and 30 MHz. The images were analyzed using the plot profile derived from freeware image analysis software: NIH Image (National Institutes of Health; Bethesda, MD). The measured echo intensity of the bronchial wall was statistically analyzed. RESULTS: A normal bronchial wall image consists of five layers, and the plot profile shows a W-shaped curve. The mean value of the echo intensity of each peak or trough of the W-shaped curve was calculated and compared for both probes. The differences in the mean echo intensity between both the third and fourth layer and the second and fourth layer were found to be significantly greater with the 30-MHz probe than with the 20-MHz probe. The echo intensity curve of a central-type lung cancer was not W shaped, indicating that the bronchial wall was not composed of the normal five layers. CONCLUSION: We employed image analysis software and drew a plot to obtain a W-shaped curve from the EBUS image data. This enabled us to make an objective assessment of the laminar structure of the bronchial wall. In order to clearly recognize the laminar structure of the bronchial wall, the 30-MHz probe was found to be more useful than the 20-MHz probe.

Bronchi↗
PubMed1994

Diagnosis of breast implant rupture: imaging findings and relative efficacies of imaging techniques.

OBJECTIVE: The purpose of this study was to compare the efficacies of mammography, sonography, CT, and MR imaging in the detection of breast implant rupture and to analyze the imaging findings. SUBJECTS AND METHODS: Thirty-two women with 63 silicone breast implants participated in the study. All but one had signs and symptoms suggestive of rupture, and all had requested that their implants be removed before they were enrolled in this imaging study. All patients had film-screen mammography, sonography, CT, and MR imaging. Twenty-two ruptures were found at surgery; 21 were intracapsular and one was extracapsular. The relative efficacies of the imaging studies were determined, and the imaging findings were compared with the surgical results. RESULTS: Of the 32 women with 63 implants, mammographic sensitivity for detecting implant rupture was only 23% but the specificity was 98%. Sonography had a higher sensitivity (59%), but its specificity was significantly lower (79%). CT had a sensitivity of 82% and a specificity of 88%. MR was the only imaging technique that consistently provided evidence that enabled the evaluation of intracapsular and extracapsular ruptures. The sensitivity and specificity of MR imaging were 95% and 93%, respectively. CONCLUSION: Our results show that MR imaging is more sensitive and specific for the detection of breast implant rupture than is mammography, CT, or sonography.

Adult↗
PubMed2000

MR imaging of the breast in patients with positive margins after lumpectomy: influence of the time interval between lumpectomy and MR imaging.

OBJECTIVE: Postsurgical contrast enhancement resulting from inflammatory changes at the site of surgery limits the accuracy of MR imaging of the breast in diagnosing residual breast cancer. This study was undertaken to evaluate the influence of the time interval between lumpectomy and MR imaging on the diagnosis of residual breast cancer. MATERIALS AND METHODS: Sixty-eight patients who had undergone excisional biopsy with positive resection margins underwent MR imaging for evaluation of residual breast cancer and possible breast conservation. Patients were retrospectively stratified according to the time interval between lumpectomy and MR imaging. Dynamic and morphologic enhancement features were used for lesion characterization. Imaging findings were correlated with results of histopathology. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated for patients waiting 7, 14, 21, 28, 35, and 42 days after initial surgery before undergoing MR imaging of the breast. RESULTS: The time interval between lumpectomy and MR imaging of the breast had the greatest influence on the specificity and negative predictive value of MR imaging, increasing progressively over time. A plateau of highest values of 75% specificity and 86% negative predictive value was reached at 28 and 35 days after surgery, respectively. Although the sensitivity and positive predictive value showed smaller variations over time, peak values of 95% sensitivity and 92% positive predictive value were obtained at 35 and 28 days after surgery, respectively. CONCLUSION: We recommend scheduling patients with positive resection margins no earlier than 28 days after initial surgery for evaluation of residual cancer using MR imaging of the breast.

Adult↗
PubMed2004

Parallel imaging and diffusion tensor imaging for diffusion-weighted MRI of the liver: preliminary experience in healthy volunteers.

OBJECTIVE: Our aim was to determine whether parallel imaging and diffusion tensor imaging affect the measurement of apparent diffusion coefficient (ADC) during diffusion-weighted MRI of the liver in healthy volunteers. SUBJECTS AND METHODS: We performed breath-hold single-shot echo-planar diffusion-weighted MRI of the liver in 10 healthy volunteers using conventional diffusion, conventional diffusion with parallel imaging, and diffusion tensor with parallel imaging sequences. TE values for the three sequences were 83, 74, and 63, respectively. Liver signal intensity was measured on all sequences and normalized to the SD of the measurement. Hepatic ADC was calculated by acquiring all sequences with b values of 0 and 500 sec/mm(2). RESULTS: The normalized liver signal intensity was higher on diffusion tensor with parallel imaging and conventional diffusion with parallel imaging than on conventional diffusion without parallel imaging for a b value of 500 sec/mm(2) (13.0 and 10.1 vs 9.1, respectively; p < 0.03) and for a b value of 0 sec/mm(2) (9.0 and 7.6 vs 6.9, respectively; without reaching a significant difference, p = 0.12). Hepatic ADC was not significantly different between sequences (p = 0.16). CONCLUSION: Higher signal intensity can be obtained when using parallel imaging and diffusion tensor imaging during diffusion-weighted MRI of the liver without compromising hepatic ADC measurement.

Adult↗
PubMed1999

Value of diffusion-weighted imaging and apparent diffusion coefficient in recent cerebral infarctions: a correlative study with contrast-enhanced T1-weighted imaging.

BACKGROUND AND PURPOSE: The clinical usefulness and the time course of diffusion-weighted imaging and apparent diffusion coefficient (ADC) in acute and subacute cerebral infarction have not yet been established, although it is known that contrast-enhanced T1-weighted spin-echo imaging can detect a subacute infarct. Our aim was to study which imaging technique is useful in detecting recent infarcts, and whether an increase in ADC or a decrease in signal intensity on diffusion-weighted images is correlated with enhancement on T1-weighted spin-echo images. METHODS: Forty-one infarctions with a duration of 9 hours to 27 days were studied in 29 patients. The ADC and signal intensity on diffusion-weighted images were compared with the contrast-enhancement ratio (CER) on T1-weighted spin-echo images (CER = signal intensity after contrast injection/signal intensity before contrast injection). RESULTS: ADC was linearly correlated with CER, and signal intensity on diffusion-weighted images was inversely correlated with CER. The correlation between ADC and age of the infarct in the subacute phase was weak. CONCLUSION: Diffusion-weighted and contrast-enhanced T1-weighted spin-echo images complement each other in detecting subacute infarcts. Neovascularization and disruption of the blood-brain barrier in infarcts can be important in increasing ADC in subacute infarcts.

Aged↗
PubMed2000

Sextant localization of prostate cancer: comparison of sextant biopsy, magnetic resonance imaging and magnetic resonance spectroscopic imaging with step section histology.

PURPOSE: We compared the accuracy of endorectal magnetic resonance imaging (MRI) and magnetic resonance spectroscopic imaging with that of sextant biopsy for the sextant localization of prostate cancer. MATERIALS AND METHODS: Sextant biopsy, MRI, magnetic resonance spectroscopic imaging and radical prostatectomy with step section histology were done in 47 patients with prostate cancer. For each sextant we categorized biopsy and imaging results as positive or negative for cancer. Step section histology was used as the standard of reference. RESULTS: For sextant localization of prostate cancer MRI and magnetic resonance spectroscopic imaging were more sensitive but less specific than biopsy (67% and 76% versus 50%, and 69% and 68% versus 82%, respectively). The sensitivity of sextant biopsy was significantly less in the prostate apex than in the mid prostate or prostate base (38% versus 52% and 62%, respectively). MRI and magnetic resonance spectroscopic imaging had similar efficacy throughout the prostate compared with biopsy only as well as better sensitivity and specificity in the prostate apex (60% and 75%, and 86% and 68%, respectively). A positive biopsy or imaging result had 94% sensitivity for cancer and concordant positivity by all 3 tests was highly specific at 98%. CONCLUSIONS: Overall MRI and magnetic resonance spectroscopic imaging have accuracy similar to biopsy for intraprostatic localization of cancer and they are more accurate than biopsy in the prostate apex. These 2 imaging modalities may supplement biopsy results by increasing physician confidence when evaluating intraprostatic tumor location, which may be important for planning disease targeted therapy.

Aged↗
PubMed2000

Preoperative cochlear implant imaging: is magnetic resonance imaging enough?

OBJECTIVE: To investigate the accuracy of magnetic resonance imaging (MRI) as a preoperative imaging technique for cochlear implant candidates. STUDY DESIGN: Retrospective, blinded. SETTING: Tertiary medical center. PATIENTS: 31 cochlear implant candidates with various causes of hearing loss. INTERVENTION: Cochlear implant patients received preoperative high-resolution temporal bone computed tomography (CT), and high-resolution T2-weighted fast spin echo MRI (FSE-MRI). The images were read independently of each other and in a blinded manner by two neuroradiologists. The imaging results were also correlated with intraoperative findings. MAIN OUTCOME MEASURES: Lack of agreement between the findings for either imaging technique; also, lack of agreement between imaging findings and intraoperative findings. RESULTS: FSE-MRI is equal to CT imaging in the detection of abnormalities of cochlear patency. It is better than CT imaging in detecting cochlear dysplasia and large vestibular aqueducts, and in determining the presence of the cochlear nerve. CONCLUSION: FSE-MRI is accurate in predicting inner ear anomalies and obstruction of the cochlear lumen. It also adds information not gathered from CT imaging, such as the presence and size of the cochlear nerve.

Cochlear Implantation↗
PubMed2000

Diffusion-weighted imaging of patients with subacute cerebral ischemia: comparison with conventional and contrast-enhanced MR imaging.

BACKGROUND AND PURPOSE: The importance of diffusion-weighted imaging (DWI) for delineating acute ischemic lesions has been investigated extensively; however, few studies have investigated the role of DWI in the subacute stage of stroke. Because these lesions tend to appear bright throughout the first days of ischemia, owing to restricted diffusion, we speculated that DWI could also improve the detection of subacute infarcts as compared with conventional and contrast-enhanced MR imaging. METHODS: Interleaved echo-planar DWI with phase navigation was performed on a 1.5-T MR unit in a consecutive series of 53 patients (mean age, 66 +/- 14 years) with suspected recent cerebral ischemia. The interval between onset of clinical symptoms and MR imaging ranged from 1 to 14 days (mean, 6 +/- 4 days). Contrast material was given to 28 patients in a dose of 0.1 mmol/kg. RESULTS: DWI clearly delineated recent ischemic damage in 39 patients (74%) as compared with 33 (62%) in whom lesions were identified or suspected on conventional T2-weighted images. DWI provided information not accessible with T2-weighted imaging in 17 patients when evidence of lesion multiplicity or detection of clinically unrelated recent lesions was included for comparison. Subacute ischemic lesions were also seen more frequently on DWI sequences than on contrast-enhanced images (20 versus 13 patients). DWI was more likely to make a diagnostic contribution in the first week of stroke and in patients with small lesions or preexisting ischemic cerebral damage than was conventional MR imaging. CONCLUSION: Recent ischemic damage is better shown on DWI sequences than on conventional and contrast-enhanced MR images throughout the first days after stroke and may provide further information about the origin of clinical symptoms. Adding DWI to imaging protocols for patients with subacute cerebral ischemia is recommended.

Adult↗
PubMed2001

[Gadolinium-enhanced MR imaging, T2-weighted MR imaging, and transurethral ultrasonography].

PURPOSE: To assess the value and problems of dynamic gadolinium-enhanced MR imaging, T2-weighted MR imaging, and transurethral ultrasonography(TUUS) in staging of urinary bladder cancer. MATERIALS AND METHODS: Dynamic gadolinium-enhanced MR imaging and FSE T2-weighted MR imaging of 64 patients with urinary bladder cancer who subsequently had surgery were retrospectively reviewed and compared with TUUS findings. RESULTS: Specificity for muscular invasion was 90.5% with TUUS, significantly better than with dynamic MR imaging (64.9%) (p < 0.05). The rates of overestimation of superficial cancer(pT1) with dynamic MRI and T2-weighted MR imaging were 35.1%(13/37) and 24.3%(9/37), respectively. The staging accuracy of invasive cancer(pT2 or over) was 85.2% with dynamic MR imaging, which was better than the rate of 75.0% achieved with T2-weighted MR imaging. CONCLUSION: Although TUUS was a better modality for diagnosing superficial cancer(pT1), dynamic MR imaging was found to be better for diagnosing invasive(pT2 or over) cancer.

Adolescent↗
PubMed2002

Neuroimaging in pediatric brain tumors: Gd-DTPA-enhanced, hemodynamic, and diffusion MR imaging compared with MR spectroscopic imaging.

BACKGROUND AND PURPOSE: Gadolinium-enhanced MR images assist in defining tumor borders; however, the relation between tumor cell extent and contrast-enhanced regions is unclear. Our aim was to improve conventional neuroimaging of pediatric brain tumors with hemodynamic, diffusion, and spectroscopic MR imaging. METHODS: We performed conventional MR and MR spectroscopic imaging in 31 children with neuroglial brain tumors. Hemodynamic MR imaging was performed in 16 patients with a first-pass intravenous bolus of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA); apparent diffusion coefficients (ADCs) were measured in 12 patients. To account for multiple measurements in a patient, we used a nested analysis of variance. RESULTS: At MR spectroscopy, choline (Cho)-containing compounds (indicating tumor) and lipid levels (indicating necrosis) did not correlate with percent Gd-DTPA enhancement on MR images. Percent enhancement was positively correlated with relative cerebral blood volumes (rCBVs) (P =.05) and negatively correlated with ADCs (P <.001). Stepwise multiple linear regression revealed that rCBV (P =.008), ADC (P =.022), and lipid (P <.001) levels were significant independent predictors of percent enhancement. Tumor spectral patterns were detected in tumor regions and outside enhancing tumor beds in patients with clinical progression; these were confirmed at neuropathologic analysis. CONCLUSION: MR spectroscopic imaging improves the assessment of pediatric brain tumors by adding biochemical information regarding tumor involvement and by depicting residual or recurrent tumor outside the Gd-DTPA-enhanced tumor bed. rCBV and ADC mapping complemented MR spectroscopic imaging. We recommend the use of MR spectroscopic imaging in addition to conventional MR imaging in assessing pediatric brain tumors.

Adolescent↗
PubMed2002

Mitochondrial encephalomyopathy: comparison of conventional MR imaging with diffusion-weighted and diffusion tensor imaging: case report.

SUMMARY: Conventional MR imaging, MR spectroscopy, diffusion-weighted imaging, and diffusion tensor imaging were performed in a 5-month-old male patient with mitochondrial encephalomyopathy. On conventional T2-weighted MR images, symmetric, confluent high signal intensity was found in the temporoparietal white matter. A large lactate peak and decreased N-acetylaspartate were found in this region on proton MR spectroscopic images. Diffusion-weighted imaging showed increased apparent diffusion coefficient, representing vasogenic edema. Diffusion tensor imaging revealed decreased anisotropy, consistent with injury to the oligodendro-axonal unit. A muscle biopsy specimen revealed an isolated complex III enzyme respiratory chain deficiency. Diffusion-weighted and diffusion tensor imaging are valuable techniques for the characterization of hyperintense lesions on T2-weighted MR images in cases of mitochondrial encephalomyopathy.

Anisotropy↗
PubMed2002

[X-ray phase imaging using a X-ray tube with a small focal spot -improvement of image quality in mammography-].

Phase contrast X-ray imaging has been studied intensively using X-rays from synchrotron radiation and micro-focus X-ray tubes. However, these studies have revealed the difficulty of this technique's application to practical medical imaging. We have created a phase contrast imaging technique using a molybdenum X-ray tube with a small focal spot size for mammography. We identified the radiographic conditions in phase contrast magnification mammography with a screen-film system, where edge effect due to phase contrast overcomes geometrical unsharpness caused by the 0.1mm-focal spot of a molybdenum X-ray tube. The edge enhancement due to phase imaging was observed in an image of a plastic tube, and then geometrical configuration of the X-ray tube, the object and the screen-film system was determined for phase imaging of mammography. In order to investigate a potential for medical application of this method, we conducted evaluation of the images of ACR 156 mammography phantom. We obtained higher scores for phase imaging using high speed screen-film systems without any increase of X-ray dose than the score for contact imaging using a standard speed screen-film system.

Female↗
PubMed2005

Estimation of contrast of refraction contrast imaging compared with absorption imaging-basic approach.

PURPOSE: We discuss the usefulness of the refraction contrast method using highly parallel X-rays as a new approach to minute lung cancer detection. The advantages of refraction contrast images are discussed in terms of contrast, and a comparison is made with absorption images. MATERIALS AND METHODS: We simulated refraction contrast imaging using globules with the density of water in air as models for minute lung cancer detection. The contrast intensified by bright and dark lines was compared on a globule with the contrast of absorption images. We adopted the Monte Carlo simulation to determine the strength of the profile curve of the photon counts at the detector. RESULTS: The obtained contrasts were more intense by two to three digits than those obtainable with the absorption contrast imaging method. CONCLUSION: The contrast in refraction contrast imaging was more intense than that obtainable with absorption contrast imaging. A two to three digit improvement in contrast means that it is possible to greatly reduce the exposure dose necessary for imaging. Therefore, it is expected to become possible to detect the interfaces of soft tissues, which are difficult to capture with conventional absorption imaging, at low dosages and high resolution.

Absorption↗
PubMedDate not supplied

[Interdependencies between the ideal self-image and the ideal image of parents in women with anorexia nervosa].

AIM: The aim of this work was to answer the following question: in the perception of patients, what kind of dependencies occur between ideal images of women with anorexia and ideal images of their mothers and fathers. TEST GROUP AND METHOD: The examined group consisted of 30 patients diagnosed with anorexia nervosa, undergoing treatment at the Department of Psychiatry of the Medical University in Lublin. The average age of the examined females was 21 years. The ideal images were examined with the Gough and Heilbrun Adjective Check List (ACL), which was completed by the patients three times following the instruction: "I would like to be", "I would like my mother to be", "I would like my father to be". RESULTS: 24 statistically significant correlations were obtained between ideal images of the patients and their mothers, whereas between the ideal images of the patients and their fathers the number of positive significant correlations was 21. CONCLUSIONS: 1. Dependencies were found between ideal images of the patients and their mothers as regards nurturance, intraception, affiliation, exhibition, dominance, autonomy, abasement and heterosexuality, self-discipline, self-control, ambition, diligence and self-confidence. 2. Dependencies were found between ideal images of the patients and their fathers as regards achievement, dominance, intraception, nurturance, affiliation, autonomy, aggression, exhibition and heterosexuality, self-control, ambition, resoluteness, self-confidence as well as such characteristics as: protectiveness, spontaneity and responsibility. 3. The following dependencies occur between ideal images of mothers and ideal images of fathers as perceived by women with anorexia: need for dominance, exhibition, heterosexuality and nurturance, deference and ambition.

Adult↗
PubMed2006

MR imaging, MR spectroscopy, and diffusion tensor imaging of sequential studies in neonates with encephalopathy.

BACKGROUND: Although the imaging, spectroscopic, and diffusion characteristics of brains of infants with neonatal encephalopathy have been described, the time course during which these changes evolve is not clear. The results of sequential MR imaging studies--including anatomic MR imaging, proton MR spectroscopy, and diffusion tensor imaging (DTI)--of 10 patients enrolled prospectively in a study of neonatal encephalopathy are reported to help to clarify the time course of changes in different brain regions during the first 2 weeks of life. METHODS: Ten neonates were prospectively enrolled in a study of the evolution of MR findings in neonatal encephalopathy and were studied 2 (8 patients) or 3 (2 patients) times within the first 2 weeks of life. The MR examination included spin-echo T1 and T2-weighted images, DTI, and long echo time (288 milliseconds) proton MR spectroscopy. Diffusion parameters (diffusivity [D(av)], fractional anisotropy [FA], and individual eigenvalues) were calculated for 10 1-cm2 regions of interest in each hemisphere that were placed based on anatomic landmarks. D(av) and FA were then measured manually in the same areas on a workstation. Metabolite ratios (NAA/Ch, Cr/Ch, Cr/NAA, Lac/Ch, and Lac/NAA) were calculated in 7 regions of interest. Imaging appearance, diffusion parameters, and metabolite ratios were then evaluated longitudinally (comparing with other studies on the same patient at different times) and cross-sectionally (comparing all studies performed on the same postnatal day). RESULTS: In most of the patients a characteristic evolution of DTI and MR spectroscopy parameters was seen during the first 2 weeks after birth. Although the anatomic images were normal or nearly normal on the first 2 days after birth in most patients, abnormalities were detected on DTI (both visually and by quantitative interrogation of D(av) maps) and proton MR spectroscopy (abnormal metabolite ratios). These parameters tended to worsen until about day 5 and then normalize, though in several patients abnormal metabolite ratios persisted. Of interest, as areas of abnormal diffusivity pseudonormalized within one region of the brain they would develop in other areas. Therefore, the pattern of injury looked very different when imaging was performed at different times during this evolution. CONCLUSION: Patterns of injury detected by standard anatomic imaging sequences, DTI sequences, and proton MR spectroscopy varied considerably during the first 2 weeks after injury. The appearance of new areas of reduced diffusion simultaneous with the pseudonormalization of areas that had reduced diffusion at earlier times can result in an entirely different pattern of injury on diffusivity maps acquired at different time points. Awareness of these evolving patterns is essential if studies are performed and interpreted during this critical period of time.

Brain Diseases↗