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Biomedical subjects

L Martí-Bonmatí

Publications and source records attributed to L Martí-Bonmatí.

At least 19 recordsLinked to original sources
PubMed2006

Accurate quantification methods to evaluate cervical cord atrophy in multiple sclerosis patients.

OBJECT: Automatic accurate measurement techniques are needed to increase reproducibility in the quantification of cervical cord area (CCA) with magnetic resonance (MR) imaging in the assessment of central nervous system (CNS) atrophy in multiple sclerosis (MS) patients. MATERIALS AND METHODS: Two segmentation methods were implemented: (1) spatial mean brightness level estimation (SMBLE), and (2) partial-volume modeling (PVM). These were evaluated with the inclusion of spinal cord inclination and/or partial-volume-effect corrections. An averaged manually segmented set was considered as reference. Thirty MR studies were used to compare the different methods. A set of 15 MS patients and 15 control subjects within a two-year longitudinal study were used to evaluate cord atrophy with the best method. Statistical evaluation was made by using an intraclass correlation coefficient and Bland-Altman comparisons. RESULTS: Partial-volume modeling with spinal cord inclination correction and partial-volume spinal-cord contour contribution estimation was the most accurate method. The longitudinal test showed a 4% decrease in CCA in MS patients with no significant reduction in control subjects. CONCLUSION: The automatic PVM cord-segmentation approach, taking into consideration the spinal-cord inclination and partial-volume treatment, provides reproducibility and increased accuracy in the evaluation of cord atrophy, allowing the monitoring of changes in MS patients.

Adolescent↗
PubMed2006

MRS as endogenous molecular imaging for brain and prostate tumors: FP6 project "eTUMOR".

Molecular imaging has become during the last years in an important tool for supporting cancer diagnosis and prognosis. PET and SPECT are the most common molecular imaging techniques, although very promising and specific biological molecular agent contrast for CT and MRI are being recently developed. However, the above imaging techniques require exogenous contrast agents and usually a sole molecular image can be obtained at once. On the contrary, in vivo magnetic resonance spectroscopy (MRS), in particular 1H MRS can simultaneously provide several molecular images using endogenous metabolites. In addition to biochemical spatial information from molecular imaging spectroscopy, MRS can also provide average metabolite profile of the selected affected tissue region. Initially MRS, especially 1H MRS, was extensively applied to complete and improve the diagnosis and prognosis of central nervous system (CNS) pathologies, in particular brain tumors. However, during the last years the MRS applications have been extent to the diagnosis of different very common cancer types such as breast, prostate, colon carcinoma, and ovarian, among others. Likewise, MRS has been also used for lymph node assessment. In this contribution, the added value of MRS for the diagnosis, prognosis, and treatment selection of two different, important types of cancer: (1) brain tumors and (2) prostate, will be presented and discussed. Brain tumors are the leading cause of death in children under 15, and although in adults, brain cancers are proportionately less common than other cancers, it is a devastating disease with high mortality. There is a great need to increase our understanding of brain tumor biology to improve diagnosis and to develop new treatments. 1H MRS is currently the only noninvasive method that can be used to investigate molecular profile of brain tumors and also provide molecular images, more than six in one acquisition, of the distribution of chemicals in a tumor, which are also generally heterogeneous. A summary of the applications of 1H MRS to the in vivo diagnosis and prognosis of brain tumors will be presented. In addition, examples of metabolite limits, infiltration and high cellularity location for neurosurgery applications by MRS molecular images will be shown. Likewise, new ex vivo methods of studying the detailed biochemistry of tumor biopsies as metabolomic (high resolution magic angle spinning [HR-MAS]) and transcriptomic (DNA microarrays) will be discussed as complementary to in vivo MRS (FP6 European project eTUMOR). A preliminary comparison between molecular images from PET and 1H MRS will be also presented. Finally, the application of 1H MRS to the improvement of prostate diagnosis and prognosis, the second leading cause of cancer death, will also discussed, with particular attention to the location cancer contribution from MRS molecular images.

Brain Neoplasms↗
PubMed2006

Low-high and high-low biphasic injection forms in computed tomography examinations of the upper abdomen.

PURPOSE: To analyze the influence of different biphasic and monophasic injection rate protocols in abdominal computed tomography (CT). MATERIAL AND METHODS: A randomized, consecutive, parallel group study was designed and conducted in 60 patients studied with the same CT helical protocol. Patients were randomly distributed into three groups: (A) monophasic (120 ml at 2.5 ml/s); (B) low-high biphasic (120 ml, first 60 ml at a rate of 2 ml/s, the other 60 ml at 2.5 ml/s); and (C) high-low biphasic (120 ml, first 60 ml at a rate of 2.5 ml/s, the other 60 ml at 2 ml/s). All patients were injected with 300 mg I/ml non-ionic contrast media at a fixed delay time of 55 s. Contrast enhancement efficacy was evaluated by attenuation coefficient measurements. RESULTS: Although non-significant, monophasic protocol enhancements were higher than biphasic protocol enhancements in all measurements except aortic bifurcation (p=0.003). At this level, biphasic protocols obtained an increased mean enhancement from 7.6% to 2.5% compared to monophasic protocols. CONCLUSION: Monophasic contrast agent injection in helical CT of the upper abdomen produces a higher enhancement of parenchymal and venous structures. No significant difference was observed between low-high and high-low biphasic protocols.

Adult↗
PubMed2005

Magnetic resonance myelography evaluation of the lumbar spine end plates and intervertebral disks.

PURPOSE: To evaluate the value of magnetic resonance (MR) myelography in the evaluation of intervertebral disk and end-plate degenerative changes in the lumbar spine. MATERIAL AND METHODS: Conventional MR and MR myelography examinations were performed in 150 consecutive patients (69 F and 81 M, mean age 45+/-15 years, range 18 89). Sagittal T1 and T2-weighted TSE images were compared to MR myelography obtained with a multishot-TSE-T2-weighted sequence (4000/250/fat suppression). Coronal, sagittal, and both oblique MR myelography projections were obtained. Image analysis was carried out independently by two radiologists who categorized lumbar disks into normal, degenerated, or edematous; and vertebral end plates into normal, edematous, or with fatty changes. The proportions were statistically compared at every lumbar intervertebral level. RESULTS: There was good agreement in the classification of disk disease (Kappa: 0.8-0.9). MRI detected a larger number of disk degeneration and end-plate fatty metamorphosis, while the MR myelography technique depicted a larger number of edematous disks and end plates. CONCLUSION: MR myelography was of limited value in detecting the same vertebral end-plate changes observed in MRI, although with similar findings in disk disease. However, the higher detection of edema changes by MR myelography should be analyzed prospectively, as it could be more sensitive than conventional MR sequences.

Adolescent↗
PubMed2005

[Hierarchical structure of authors collaboration. An analysis of papers on imaging diagnosis published by hospital radiology departments in Comunidad Valenciana (1994-2001)].

OBJECTIVE: Analyze the different contribution of hierarchical categories in the papers published by radiologists of hospitals belonging to Comunidad Valenciana along the period 1994-2001, as well as their distribution in the different journals. MATERIAL AND METHODS: For the recovery of the papers sample we have designed specific search profiles for EMI and Medline databases. Hierarchical category of the authors was identified through personal interviews. RESULTS: We have analyzed 417 works, with 1,321 authors distributed in the following form: chief of service, 8.8%; chief of section, 12.4%; assistant physician, 50.7%, and resident, 28%. Hierarchical groupings with participation of residents were more consistent for publishing papers along all the study period (1994-2001). Higher percentage of papers (21%) corresponded to < > grouping. Radiología was the most productive journal (42% papers). All results were statistically significant (p < 0.0001). CONCLUSION: Radiodiagnosis residents of Comunidad Valenciana hospitals showed an active participation in research papers published along the period 1994-2001, in collaboration with the rest of the hierarchical categories, basically with the assistant physician. Assistant physicians contributed most of papers. Chief of section and chief of department contributed fifth of papers.

Databases as Topic↗
PubMed2004

Dural enhancement with primary calvarial lesions.

The purpose of this study was to relate the pathological and imaging features of dural enhancement and meningeal sign ("dural tail") on contrast-enhanced T1-weighted magnetic resonance (MR) images from patients with primary calvarial lesions as well to assess the accuracy of MR imaging in predicting dural invasion. Thirty-two calvarial tumors studied with contrast-enhanced MR imaging and histopathological examination of the dural specimens were reviewed. Sixteen patients presented dural enhancement, eight with tumor invasion. Tumoral invasion of the dura was observed in one case without enhancement. Malignant lesions showed enhanced dura more commonly than benign lesions (P=0.02). Nodular and discontinuous dural enhancement was statistically associated with dural invasion (P=0.05). Dural tail did not show a specific pathological association. Meningeal enhancement is a nonspecific reaction to calvarial lesions unless nodular and discontinuous. False-negative and -positive cases of dural invasion imply some limitation of contrast-enhanced MR imaging in predicting dural invasion by calvarial neoplasms.

Adolescent↗
PubMed2004

MR-myelography as an adjunct to the MR examination of the degenerative spine.

Our objective was to analyse the usefulness of single-slice MR-myelography images as a complementary test to conventional MR of the spine in patients with clinically suspected degenerative spine disease. A prospective analysis of 1022 consecutive patients studied with conventional MR and MR-myelography (four acquisitions: one coronal plane, one sagittal plane, and two oblique lateral, right and left planes) examinations was performed. Conventional MR and MR-myelography studies were classified as positive when morphological or structural alterations were noted. Positive MR-myelography information was also categorized as relevant if findings were considered important and radiologically significative to the final diagnosis (either by increasing the radiologists confidence in the diagnosis or because the findings were not observed in the conventional study). Other positive findings were considered non- relevant. There were 62% cases considered positive in the MR-myelography examination. Of them, 3% revealed no alterations on the conventional MR examination. Of the negative MR-myelography studies, 75% had a positive conventional MR examination. Considered as diagnostic techniques, their Kappa concordance was poor. However, MR-myelography complemented the information obtained with the conventional MR examination of the spine, this information being relevant to the final MR diagnosis in 22% of the total number of cases. The contribution of MR-myelography was not different in the three spinal levels. In conclusion, MR-myelography complements the information obtained with conventional MR in a large number of cases.

Aging↗
PubMed2004

Cognitive impairment: classification by 1H magnetic resonance spectroscopy.

1H magnetic resonance spectroscopy (MRS) allows accurate and non-invasive in vivo metabolic study, and is a useful tool for the diagnosis of different forms of dementias. Cognitive impairment pathologies have been almost exclusively studied with MRS by comparison with healthy without a global comparison amongst Alzheimer disease (AD), vascular dementia, mild cognitive impairment (MCI) and major depression patients with cognitive impairment. Whereas decrease of N-acetylaspartate (NAA) and increase myo-Inositol (mI) at different brain locations by 1H MRS are common features of AD, Choline (Cho) alterations have been inconclusive. In our study, 64 patients with cognitive impairment were evaluated by 1H MRS using two echo times (31 and 136 ms). There were statistical differences between dementia (AD and vascular dementia) and non-dementia (MCI and depression) spectra at posterior cingulate gyrus. Cho/Cr, mI/Cr and NAA/Cr have been valuables for the differentiation amongst the different cognitive impairment entities. NAA/mI provides the best area under the ROC curve with the highest sensitivity (82.5%) and specificity (72.7%) in diagnosing AD. NAA/mI and mI/Cr ratios differed amongst the four cognitive impairment degenerative pathologies. Metabolic MRS differences found amongst patients with cognitive impairment entities can be useful to differentiate between AD, vascular dementia, MCI and depression.

Aged↗
PubMed2003

Evidence of Wallerian degeneration in normal appearing white matter in the early stages of relapsing-remitting multiple sclerosis: a HMRS study.

OBJECTIVE: Wallerian degeneration in normal appearing white matter in early relapsing-remitting multiple sclerosis (RRMS), and its correlation with the number of relapses and disease duration. Background Recent pathological studies have demonstrated Wallerian degeneration in normal appearing white matter (NAWM) in multiple sclerosis (MS), in established RRMS, and in chronic MS. However, the presence of Wallerian degeneration early in the disease and its correlation with relapse and with disease duration has not been studied. METHODS: We performed proton magnetic resonance spectroscopic imaging in 21 MS patients, and 4 healthy controls, age and gender matched, aged under 45 years, with a maximum of 4 years since first bout, and an EDSS score of less than 3.0. N-acetyl-aspartate (NAA) (an index of axonal integrity) was measured in the NAWM from the pons and the cerebellar peduncles. RESULTS: We observed that the NAA levels were abnormally low in the NAWM in the early RRMS patients (p = 0.04, Student's t-test). The decrease in the NAA concentration correlated with disease duration in the two areas studied (p = 0.03 for pons and p = 0.04 for cerebellar peduncle); and with the number of previous relapses (Pearson's correlation = -0.582, p < 0.002). CONCLUSION: Wallerian degeneration measured by the NAA concentration at pons and cerebellar peduncles is present early in the disease and correlates with the number of relapses and disease duration.

Adolescent↗
PubMed2003

[Diagnosis of calvarial lesions. Feature selection by neural network and logistic regression].

OBJECTIVES: To establish the minimun set of features needed in the diagnosis of calvarial lesions using computed tomography (CT) and to assess the accuracy of logistic regression (LR) and artificial neural networks (NN) for their diagnosis. MATERIAL AND METHODS: 167 patients with calvarial lesions as the only known disease were enrolled. The clinical and CT data were used for LR and NN models. Both models were tested with the jacknife method. The final results of each model were compared using the area under ROC curves (A 2 ). RESULTS: The lesions were 73.1 % benign and 26.9% malignant. There was no statistically significant difference between LR and NN in differentiating malignancy. In characterizing the histologic diagnoses, NN was statistically superior to LR. Important NN features needed for malignancy classification were age and edge definition, and for the histologic diagnoses matrix, marginal sclerosis and age. CONCLUSIONS: A minimum four features is needed to diagnose these lesions, not being important patients' symptoms. NNs offer wide possibilities over statistics for the calvarial lesions study besides a superior diagnostic performance.

Adolescent↗
PubMed2002

The value of fat-suppressed T2 or STIR sequences in distinguishing lipoma from well-differentiated liposarcoma.

The objective of this study was to evaluate the diagnostic value of fat-suppressed T2-weighted (FS-T2) images or short tau inversion recovery (STIR) imaging in distinguishing lipoma from lipoma-like subtype of well-differentiated liposarcoma. Spin-echo T1-weighted and STIR or fat-suppression T2-weighted sequences were performed in 60 lipomas and 32 lipoma-like well-differentiated liposarcomas, histologically proven, looking for thick septa or nodules in T1-weighted images and linear, nodular, or amorphous hyperintensities on FS-T2/STIR sequences. Fourteen lipomas (23.3%) showed thick septa and/or nodules on T1, whereas on FS-T2 or STIR sequences only seven (11.7%) displayed hyperintense nodules and/or septa. All well-differentiated liposarcomas contained these signs on FS-T2 or STIR sequences. The presence of hyperintense septa or nodules in a predominantly lipomatous tumor on FS-T2/STIR sequences helps to differentiate malignant tumors from lipomas. Employing the presence of hyperintense nodules and/or septa as criteria of malignancy specificity was 76.6% and sensitivity 100%. Overdiagnoses of well-differentiated liposarcoma can occur due to the presence of non-lipomatous areas within lipomas.

Adipose Tissue↗
PubMed2001

[Abdominal fat assessment by magnetic resonance: comparison with biometric profiles and cardiovascular risk markers].

BACKGROUND: Obesity is associated with numerous metabolic complications and cardiovascular disease. Magnetic Resonance (MR) imaging provides fair resolution of fat distribution, its quantification by semiautomatic methods being feasible. Our purpose was to analyze abdominal fat deposition by MR imaging and quantify its relative distribution in 50 obese patients. RESULTS were then related to anthropometric measures and cardiovascular risk markers. PATIENTS AND METHOD: Six axial T1-weighted abdominal images were obtained from each patient and transferred to a PC. A software (ASYMED 3.0; Valencia) was used to analyze the images and quantify relative fat deposition. Comparison of MR results with several cardiovascular risk markers was performed using unpaired data Student t-test. Significance level was defined as a P < 0.05. RESULTS: 12% of patients showed predominant intra-abdominal fat deposition.Significant differences were found with regard to age, waist-hip ratio and average serum levels of total cholesterol, LDL, VLDL,triglycerides and apoprotein B between intra-abdominal deposition versus subcutaneous fat deposition. CONCLUSION: MR imaging allows estimation of abdominal fat deposition and its relative distribution. There is a significant relationship between a predominant intra-abdominal fat deposition and an atherogeniclipid profile.

Abdomen↗
PubMed2001

[Prevalence and characteristics of complications of Baker cysts by MRI].

OBJECTIVE: To evaluate the prevalence and describe the findings of complicated Baker cysts observed in a large series of knee MR studies. MATERIALS AND METHODS: A total of 145 Baker cysts were detected out of a series of 382 (38%) consecutive patients with knee MR studies performed. Cysts were classified as simple (smooth walls, homogeneous content, signal intensity similar to that of the synovial fluid and with no changes in the surrounding tissues) or complicated (changes of wall, changes in the intensity of the content signal, presence of free bodies or changes in the surrounding tissues). Complications were detected in ten (6.9%) cysts, which were confirmed by means of direct observation (arthroscopy or surgery, n = 9 cases) or by means of clinical evidence with follow-up (n = 1 case). RESULTS: No differences were detected in sex distribution between simple and complicated cysts (chi 2, p = 0.09), although a statistically significant relationship was indeed detected between the presence of complications with older age (p = 0.003) and presence of meniscal lesions (p = 0.019). In five patients a rupture of the Baker cyst was found, in four intracystic free bodies, and in one case pigmented villonodular synovitis with intracystic foci. Only two out of the five patients with cyst rupture had thrombophlebitis symptoms, the remaining of ruptures being asymptomatic. In three out of the four patients with free intracystic bodies they were considered secondary to degenerative osteochondral lesions, the other case having synovial chondromatosis. CONCLUSIONS: Baker cysts are common and usually are not associated with complications. In our series, a prevalence of 6.8% of complicated cysts was observed, either by their contents or wall changes. The most common complication is rupture (50% of complicated cysts) which can be asymptomatic in up to 80% of cases, followed by free intracystic bodies (40% of complications) usually of degenerative origin. The complication is statistically associated with meniscal ruptures and aged patients.

Adult↗
PubMed2000

[Value of MR myelography in the diagnosis of the spine disorders].

To evaluate the utility of myelography obtained with MR imaging (MR-myelography) as a complementary tool in patients studied with a conventional MR examination of the spine. 275 consecutive patients were included. All of them were studied with MR-myelography in 2 planes, coronal and sagittal, with a turbo spin-echo single-shot technique, as a complement to a conventional MR study of the spine; 130 were males and 145 women, with ages ranging from 20 to 71 years (mean, 45 years). The analyzed variables were age, sex, vertebral segment studied, alteration of the dural sac, intradural nerve roots, emergent roots, and presence of intradural lesions, meningeal cysts, and spinal stenosis. The added value of MR-myelography regarding conventional MR was categorized. MR-myelography obtained new information in 88 cases (32%), being considered irrelevant information in 42 cases and relevant in 46 cases (16.7% of all cases) (amputations of the emergent roots and alterations of the intradural roots). MR-myelography did not contribute to any type of additional information to the conventional MR study in 187 cases (68% of all studies). MR-myelography is a rapid acquisition technique that supplements the conventional MR study of the spine, contributing with relevant new information in the analysis of the spine diseases 16.7% of cases.

Adult↗
PubMed2000

Enhancement characteristics of hepatic focal nodular hyperplasia and its scar by dynamic magnetic resonance imaging.

RATIONALE AND OBJECTIVES: To determine the relationship between the lesion and the scar enhancement characteristic in a series of hepatic Focal Nodular Hyperplasia (FNH) lesions studied with dynamic MR imaging. METHODS: Nine patients with FNH were studied. The slice showing the largest scar was selected for the dynamic single slice T1-weighted Gradient-echo sequence before and after contrast administration (15 images, one every 20 s). Analysis was performed with ROI measurements in the lesion and the scar. Signal-intensity and enhancement curves were obtained from both structures. RESULTS: Dynamic MRI showed the typical homogeneous early enhancement of the lesion with delayed enhancement of the scar. The scar enhanced early and vigorously in all cases. Two patterns of enhancement curves were defined. In the parallel pattern, both curves started early, quickly reaching a plateau maintained over time (77.8%). In the divergent pattern the curve of the scar was above the curve of the FNH (22.2%), after the maximum slope was reached, with progressive separation of the curves. CONCLUSION: There is a hypervascular scar enhancement within FNH lesions with either a parallel or divergent course after the maximum early enhancement.

Adult↗
PubMed2000

MR imaging of Baker cysts --prevalence and relation to internal derangements of the knee.

RATIONALE AND OBJECTIVES: To evaluate the prevalence of popliteal cysts in patients studied with magnetic resonance (MR) imaging. Cyst presence and volume will be related to other internal derangement of the knee. MATERIALS AND METHODS: Three hundred and eighty-two consecutive patients with a MR study of the knee were included. Images were obtained in the three spatial orthogonal planes and evaluated through consensus. Four categories were established for the Baker cyst and synovial fluid (absence, minimum, moderate and massive), and the presence of meniscal, cruciate ligaments and cartilage lesions were recorded. Statistical analysis was carried out with bivariate analysis (chi(2) of Pearson and Gamma tests). RESULTS: From the 382 patients, 145 had Baker cysts (38.0%). Cyst content was minimum in 99, moderate in 34 and massive in 12. Joint effusion was observed in 269 patients (70.4%), being minimal in 140 patients, moderate in 119 and massive in ten. Meniscal lesions were observed in 195 patients (51%), while 58 patients (15%) had a cruciate ligament lesion. Baker cyst had a statistically significant direct relationship with the presence and quantity of synovial fluid (P=0.002) and with the presence and type of meniscal lesion (P=0.01) but not with cruciate ligaments or cartilage lesions. CONCLUSIONS: The prevalence of Baker cysts in MR studies of the knee is high. Its presence and volume are related to the quantity of synovial fluid, and to the presence and severity of meniscal lesions.

Adolescent↗
PubMed2000

Klippel-Trenaunay syndrome: frequency of cerebral and cerebellar hemihypertrophy on MRI.

We examined 11 patients, clinically and radiographically diagnosed as having the Klippel-Trenaunay syndrome (KTS) by MRI. There were four females and seven males, aged 3-51 years (mean 21 years). Two had clear asymmetry of the cerebral and cerebellar hemispheres. The thickness of the grey matter was normal, without sulcation abnormalities, but the thickness of the white matter was increased; the size of the ipsilateral ventricle was normal. These patients had hypertrophy of the leg and a cutaneous haemangioma on the same side as the brain abnormality. No patient had an intracranial vascular malformation, unilateral megalencephaly, cerebral atrophy or hydrocephalus. The prevalence of cerebral hemihypertrophy in our series of patients with KTS was thus 18%.

Adolescent↗