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Objective:To investigate the performance of a predictive model based on fat suppression (FS)-T2WI sequence combined with machine learning in the differential diagnosis of brucellar spondylitis (BS) and tuberculous spondylitis (TS).Methods:The clinical and imaging data of 74 patients with BS and 81 patients with TS diagnosed clinically or pathologically in the First Affiliated Hospital of Xinjiang Medical University from January 2017 to January 2022 were retrospectively analyzed, and all patients underwent spinal magnetic resonance imaging (MRI) examination before treatment. Patients were randomly divided into a training group ( n = 123) and a testing group ( n = 32) in an 8 ∶ 2 allocation ratio, and radiomics feature extraction and dimensionality reduction analysis were performed on FS-T2WI sequence images. Four machine learning algorithms, including K-nearest neighbor (KNN), support vector machine (SVM), random forest (RF) and logistic regression (LR), were used to construct a radiomics model, and receiver operating characteristic (ROC) curve was used to analyze the differential diagnostic performance of each model for BS and TS. Results:A total of 1 409 radiomics features were extracted, and 7 related features were screened and included for identification of BS and TS, among which the Maximum2DDiameterColumn feature value showed a strong correlation, and there was a statistically significant difference between BS and TS patients ( P < 0.001). In the testing group, the area under the ROC curve (AUC) value of the SVM model for identifying BS and TS was 0.886, with a sensitivity of 0.53, a specificity of 0.88, and a diagnostic accuracy of 0.81; in the training group, the AUC value of the SVM model for identifying BS and TS was 0.811, the sensitivity was 0.68, the specificity was 0.72, and the diagnostic accuracy of the model was 0.78. Conclusion:The prediction model based on FS-T2WI sequence combined with machine learning can be used to identify BS and TS, and the diagnostic performance of SVM model is prominent and stable.
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Abstract The acquisition of images with suppression of the fat signal is very useful in clinical practice and can be achieved in a variety of sequences. The Dixon technique, unlike other fat suppression techniques, allows the signal of fat to be suppressed in the postprocessing rather than during acquisition, as well as allowing the visualization of maps showing the distribution of water and fat. This review of the Dixon technique aims to illustrate the basic physical principles, to compare the technique with other magnetic resonance imaging sequences for fat suppression or fat quantification, and to describe its applications in the study of diseases of the musculoskeletal system. Many variants of the Dixon technique have been developed, providing more consistent separation of the fat and water signals, as well as allowing correction for many confounding factors. It allows homogeneous fat suppression, being able to be acquired in combination with several other sequences, as well as with different weightings. The technique also makes it possible to obtain images with and without fat suppression from a single acquisition. In addition, the Dixon technique can be used as a quantitative method, allowing the proportion of tissue fat to be determined, and, in more updated versions, can quantify tissue iron.
Resumo A aquisição de imagens com supressão do sinal da gordura é um recurso de grande utilidade diagnóstica, existindo várias sequências capazes de realizá-la. A técnica Dixon, ao contrário de outras técnicas de supressão de gordura, permite suprimir a contribuição do sinal de gordura no pós-processamento e não durante a aquisição, além de permitir a visualização de mapas com a distribuição da água e da gordura. Esta revisão sobre a técnica Dixon almeja ilustrar os princípios físicos básicos, comparar a técnica com outras sequências de ressonância magnética para supressão ou quantificação de gordura, e descrever suas aplicações no estudo de doenças do sistema musculoesquelético. Muitas variantes da técnica Dixon foram desenvolvidas, proporcionando separação mais consistente dos sinais de gordura e água e permitindo correção de muitos fatores de confusão. Permite obter supressão homogênea de gordura, podendo ser adquirida de forma combinada com várias outras sequências, bem como com diferentes ponderações. Esta técnica possibilita também a obtenção de imagens com e sem supressão de gordura a partir de uma única aquisição. Adicionalmente, a técnica Dixon pode ser utilizada como recurso quantitativo, pois permite a mensuração do porcentual de gordura e, em versões mais atualizadas, consegue quantificar ferro tecidual.
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Objective To investigate the influence of fat suppression technique on the parameters obtained with introvoxel incoherent motion (IVIM)for the normal hip.Methods 47 female volunteers were randomly selected to perform 1.5T MR examination with common sequence and IVIM sequence.The three different Fat suppression techniques:Fat sat,SPAIR and Water Excit were utilized respectively in T2WI sequence and IVIM sequence.The value of signal-to-noise ratio (SNR),contrast-to-noise ratio (CNR),coefficient of variation(CV), ADC,Dfast,Dslowand F values for three methods were calculated and compared quantitatively.The consistency evaluation of these methods were also conducted.Results (1)ADC value and Dslowvalue obtained with the Water Excit method were higher than those with Fat sat and SPAIR statistically(P<0.05),however there was no significant differences between the SNR,CNR,CV,Dfastand F values measured in three fat suppression methods(P>0.05).(2)The results of Fat sat and SPAIR techniques exhibited good consistency.Conclusion In Water Excit technique,overestimation of the ADC and Dslowvalues may be presented,while the IVIM measurement results are not influenced by the use of Fat sat or SPAIR method.
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PURPOSE: To evaluate the diagnostic performance of three-dimensional fast spin-echo (3D FSE-Cube) without fat suppression (NFS) for detecting knee lesions, using comparison to 3D FSE-Cube with fat suppression (FS). MATERIALS AND METHODS: One hundred twenty-four patients who underwent 1.5T knee magnetic resonance imaging (MRI) scans and 25 subsequent arthroscopic surgeries were retrospectively reviewed. Using arthroscopic results and two-dimensional images as reference standards, diagnostic performances of 3D FSE-Cube-NFS and FS imaging about lesions of ligament, meniscus, subchondral bone marrow edema (BME), and cartilage were compared. Scan parameters of 3D FSE-Cube imaging were previously optimized by a porcine knee phantom. RESULTS: No significant differences were observed between detection rates of NFS and FS imaging for detecting lesions of meniscus and cartilage (p>0.05). However, NFS imaging had lower sensitivity for detection of medial collateral ligament (MCL) tears, and lower sensitivity and specificity for detection of BME lesions, compared to FS imaging (p<0.05). CONCLUSION: 3D FSE-Cube-NFS imaging showed similar diagnostic performance for detecting lesions of meniscus or cartilage compared to FS imaging, unlike MCL or BME lesions.
Subject(s)
Humans , Arthroscopy , Bone Marrow , Cartilage , Collateral Ligaments , Edema , Imaging, Three-Dimensional , Knee , Ligaments , Magnetic Resonance Imaging , Retrospective Studies , Sensitivity and Specificity , TearsABSTRACT
PURPOSE: To compare the image quality and ligament traceability in ankle images obtained using Volume Isotropic Turbo Spin Echo Acquisition (VISTA) MRI with and without fat suppression. MATERIALS AND METHODS: The signal-to-noise ratios (SNRs) in images from a phantom and from the ankle of a volunteer were compared. Ten ankles from 10 non-symptomatic volunteers were imaged for comparisons of contrast ratio (CR) and ligament traceability. All examinations were performed using VISTA sequences with and without fat suppression on a 3T MRI scanner. The SNRs were obtained from images with subjects and without subjects (noise-only). Contrast ratios from images of the 10 ankles were acquired between fluid and tendon (F-T), F-cartilage (C), F-ligament (L), fat (f)-T, f-C and f-L. Two musculoskeletal radiologists independently scored the traceability of 7 ligaments, in sagittal, axial and coronal images respectively, based on a 4-point scale (1 as not traceable through 4 as clearly traceable). The Wilcoxon signed-rank test was used to compare the CR. Fisher's exact test and Pearson's chi-squared test were used to compare the ligament traceability. RESULTS: The SNRs did not differ significantly between the two sequences except in bone marrow. VISTA SPAIR showed the higher CR only in F-T (p = 0.04), whereas VISTA showed higher CR in f-T (p = 0.005), f-C (p = 0.005) and f-L (p = 0.005). The calcaneofibular ligament traceability with VISTA was superior to that obtained with VISTA SPAIR (p < 0.05) in all planes. CONCLUSION: VISTA showed significant superiority to VISTA SPAIR in tracing CFL due to the superior CR between fat and ligament.
Subject(s)
Animals , Ankle , Bone Marrow , Ligaments , Magnetic Resonance Spectroscopy , Magnetics , Magnets , Signal-To-Noise Ratio , TendonsABSTRACT
OBJECTIVE: To compare the iterative decomposition of water and fat with echo asymmetry and the least-squares estimation (IDEAL) method with a fat-saturated T2-weighted (T2W) fast recovery fast spin-echo (FRFSE) imaging of the spine. MATERIALS AND METHODS: Images acquired at 3.0 Tesla (T) in 35 patients with different spine lesions using fat-saturated T2W FRFSE imaging were compared with T2W IDEAL FRFSE images. Signal-to-noise ratio (SNR)-efficiencies measurements were made in the vertebral bodies and spinal cord in the mid-sagittal plane or nearest to the mid-sagittal plane. Images were scored with the consensus of two experienced radiologists on a four-point grading scale for fat suppression and overall image quality. Statistical analysis of SNR-efficiency, fat suppression and image quality scores was performed with a paired Student's t test and Wilcoxon's signed rank test. RESULTS: Signal-to-noise ratio-efficiency for both vertebral body and spinal cord was higher with T2W IDEAL FRFSE imaging (p < 0.05) than with T2W FRFSE imaging. T2W IDEAL FRFSE demonstrated superior fat suppression (p < 0.01) and image quality (p < 0.01) compared to fat-saturated T2W FRFSE. CONCLUSION: As compared with fat-saturated T2W FRFSE, IDEAL can provide a higher image quality, higher SNR-efficiency, and consistent, robust and uniform fat suppression. T2W IDEAL FRFSE is a promising technique for MR imaging of the spine at 3.0T.
Subject(s)
Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Image Interpretation, Computer-Assisted , Magnetic Resonance Imaging/methods , Signal-To-Noise Ratio , Spinal Diseases/diagnosis , Statistics, NonparametricABSTRACT
In order to observe the feature of age-related marrow conversion and maturation of epi-physeal cartilage and analyze the distribution of red and yellow marrow in the proximal femur at STIR MR imaging, STIR and T1 weighted MR imaging of the proximal femur in 52 subjects, aged 4 months to 25 years old, were retrospectively analyzed for the distribution and appearance of red and yellow marrow. The subjects with no known bone marrow abnormalities were divided into 6 age groups. The signal intensity of the marrow in the proximal epiphysis, proximal metaphysis, proximal diaphysis, distal diaphysis and greater trochanter was compared with the signal intensity and homo- geneity of surrounding muscle and fat and graded by two observers. The results showed that the con- version of hematopoietic marrow in the proximal femur followed a well-defined sequence, occurring first in the proximal epiphysis, followed by the distal diaphysis, and then greater trochanter and metaphysis. STIR in combination with T1-weighted imaging could display clearly the origin of ossi-fication center and the course of conversion from red to yellow marrow in proximal epiphysis and greater trochanter. STIR imaging showed that the marrow conversion in proximal metaphysic began below epiphyseal plate and intertrochanter. The site of red yellow was distributed in weight-bearing axis by 20 years of age. The marrow conversion of diaphysis was from distal end to proximal end, and the consequence of conversion was that distal diaphysis contained yellow marrow but proximal diaphysis partly red marrow connected with the red marrow of metaphysic. The epiphyseal cartilage had different characters of signal-intensity with age in STIR sequence. The distribution of red marrow in STIR imaging was more close to that of anatomy than T1-weighted imaging. It was concluded that STIR could dynamically display the feature of morrow conversion and the development of epiphyseal cartilage and accurately reveal the age-related distribution of red and yellow marrow on STIR imag-ing in the proximal femur.
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PURPOSE: We wished to assess the merits and weaknesses of postcontrast fat-suppression (FS) brain MR imaging in children for the evaluation of various enhancing lesions as compared with postcontrast conventional T1-weighted or magnetization transfer (MT) imaging. MATERIALS AND METHODS: We reviewed the records of those patients with enhancing lesions on brain MR imaging who had undergone both FS imaging and one of the conventional T1-weighted or MT imaging as a postcontrast T1-weighted brain MR imaging. Thirty-one patients (21 male, 10 female; mean age, 8.7 years) with 38 enhancing lesions (18 intra-axial, 16 extra-axial and 4 orbital locations) were included in this study. There were 27 pairs of FS and conventional imagings, and 13 pairs of FS and MT imagings available for evaluation. Two radiologists visually assessed by consensus the lesions' conspicuity, and they also looked for the presence of flow or susceptibility artifacts in a total of 40 pairs of MR imagings. For 19 measurable lesions (14 pairs of FS and conventional T1-weighted imagings, 5 pairs of FS and MT imagings), the contrast ratios between the lesion and the normal brain ([SIlesion-SIwater]/[SInormal brain-SIwater]) were calculated and compared. RESULTS: Compared with conventional imaging, the lesion conspicuity on FS imaging was better in 10 cases (7 extra-axial lesions, 2 orbital lesions and 1 fat-containing intra-axial lesion), equal in 16 cases, and worse in one case. Compared with MT imaging, the lesion conspicuity on FS imaging was better in 3 cases (2 extra-axial lesions and 1 intra-axial lesion), equal in 8 cases, and worse in 2 cases. Image quality of FS imaging was compromised by flow or susceptibility artifacts for 7 patients. The contrast ratios for FS imaging were not significantly different from those for conventional imaging (2.2+/-0.7 vs. 2.2+/-0.6, respectively, p=0.914) and they were significantly lower than those for MT imaging (2.4+/-0.8 vs. 4.5+/-1.5, respectively, p=0.018). CONCLUSION:Postcontrast FS brain MR imaging appears to be better than the conventional T1-weighted imaging and comparable to MT imaging for the visual assessment of enhancing lesions. Especially, the FS imaging has the merit to delineate orbital and extra-axial enhancing lesions or fat-containing lesions, whereas it is disadvantageous when flow or susceptibility artifacts occur.
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Child , Female , Humans , Male , Artifacts , Brain , Consensus , Magnetic Resonance Imaging , OrbitABSTRACT
Objective To study the applied value of diffusion weighted imaging-DWIBS(diffusion weighted imaging with background suppression) in detecting the body tumour.Methods 10 healthy volunteers and 20 patients with histologically proven tumour were examined by diffusion Weighted MR with different techniques of background/fat body signal suppression.STIR-EPI sequence and spin echo-echo planar imaging(SE-EPI) sequence with chemical shift selective(CHESS) pulse were compared in terms of their degree of fat suppression.The diffusion weighted imaging features of control group and patients with tumour were observed and the values of ADC were measured.Results Fat suppression with STIR-EPI sequence in neck,chest,spine and extremity was well and SE-EPI with CHESS pulse in chest,abdomen,pelvic was satisfying.Signal to noise ratio(SNR) wss higher in SE-EPI with CHESS than that in STIR.The glands,spleen,peripheral nerves,lymph nodes and so forth could be showed by DWIBS in control group.85% malignant lesions were well visualized and appeared as high signal intensity and lower signal intensity in similar PET imaging,but the lesions only in 3 patients are not well visualized including pancreas cancer(1 case),rectum cancer(1 case),prostate cancer(1 case).PET scan was performed in 3 patients and well corresponded with diffusion weighted imaging in 2 cases,the other one was not visualized on diffusion weighted imaging.The highest ADC of malignant tumors was(1.58?2.06)?10-3mm2/s,the lowest ADC of malignant tumors was(0.88?0.74)?10-3mm2/s,the mean values of ADC of malignant tumors was(1.34?0.79)?10-3mm2/s.Conclusion DWIBS is a new method of diffusion-weighted MR,it has high spatial resolution,high contrast to noise ratio(CNR) and high SNR. This technique can be used as a powerful screening tool for tumour and evaluating the pathological lesions by measuring the values of ADC.
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PURPOSE: The purpose of this study was to evaluate the effects of magnetization transfer contrast(MTC) andfat-suppression(FS) in variable spin-echo and gradient-echo sequences for articular cartilage imaging and todetermine the optimal pulse sequences. MATERIALS AND METHODS: Using variable 7-pulse sequences, the knees of 15pigs were imaged Axial images were obtained using proton density and T2-weighted spin-echo (PDWSE and T2WSE),turbo spin-echo (TSE), multiplanar gradient-echo (MPGR), and 3D steady-state gradient-echo (3DGRE) sequences, andthe same pulse sequences were then repeated using MTC. Also T1-weighted spin-echo(T1WSE) and 3D spoiledgradient-echo(3DSPGR) images of knees were also acquired, and the procedure was repeated using FS. For each knee,a total of 14 axial images were acquired, and using a 6-band scoring system, the visibility of and thevisibilities of the the articular cartilage was analyzed. The visual effect of MTC and FS was scored using a4-band scale. For each image, the signal intensities of articular cartilage, subchondral bone, muscles, and salinewere measured, and signal-to-noise ratios(SNR) and contrast-to-noise ratios(CNR) were also calculated. RESULTS: Visibility of the cartilage was best when 3DSPGR and T1WSE sequences were used. MTC imaging increased the negativecontrast between cartilage and saline, but FS imaging provided more positive contrast. CNR between cartilage andsaline was highest when using TSE with FS(-3 5 1 . 1 +/-15.3), though CNR between cartilage and bone then fell to-1 4 . 7 +/-10.8. In MTC imaging using MPGR showed the greatest increase of negative contrast between cartilage andsaline(CNR change=-74.7); the next highest was when 3DGRE was used(CNR change=-34.3). CNR between cartilage andbone was highest with MPGR(161.9 +/-17.7), but with MTC, the greatest CNR decrease(-81.8) was observed. Thegreatest CNR increase between cartilage and bone was noted in T1WSE with FS. In all scans, FS provided acartilage-only positive contrast image, though the absolute value of CNR was lower than that of MTC imaging. CONCLUSION: The most prominent effects of MTC and FS were seen in MPGR and T1WSE, respectively, though forcartilage, optimal high signal intensity and contrast can be achieved using 3DGRE with MTC, and 3DSPGR with FS.
Subject(s)
Cartilage , Cartilage, Articular , Knee , Magnetic Resonance Imaging , Muscles , ProtonsABSTRACT
PURPOSE: To compare the value of Gd-DTPA enhanced, fat-suppression T1-weighted (Gd-FST1SE) MR images in thediagnosis of female pelvic disorders with that of fast spin-echo T1-weighted(T1FSE) and fast spin-echoT2-weighted(T2FSE) MR images. MATERIALS AND METHODS: Pelvic MR images of 42 women (24 ovarian disorders, 19uterine disorders) were reviewed by two radiologists. Discrimination of normal anatomic structures, identificationof pathologic lesions and recognition of internal structure of the lesions such as solid and cystic portion,papillary nodule, septa and wall were evaluated using a scoring system. The Friedman two-way ANOVA test was usedfor data analysis. RESULT: T2FSE was useful for evaluation of the uterine cervix(T1/T2/Gd, 2.5/3.9/2.8,respectively), junctional zone(1.6/3.1/2.5), endometrium (2.0/3.3/3.0), ovary(1.1/2.1/1.7) and uterine myoma(1.7/2.4/2.1)(P<0.001), but secondary degeneration was best visualized on Gd-FS T1SE. The Gd-FS T1SE ;lymphadenopathy(3.4/1.5/3.7) was better visualised on this modality than on eithor TIFSE or T2FSE. Gd-FS T1SEimages also clearly depicted papillary projection(2.4/3.1/3.8) and the solid component (2.9/3.1/3.5) of ovariancystic neoplasm(P<0.01). The confidence level in the identification of ovarian mass, internal septation andsurrounding wall of cystic neoplasm was not improved on Gd-FS T1SE. CONCLUSION: The Gd-FS T1SE images were usefulfor the evaluation of metastatic lymphadenopathy in uterine cervical malignancy and for identification of thesolid component and papillary projection of ovarian cystic neoplasm.
Subject(s)
Female , Humans , Discrimination, Psychological , Endometrium , Gadolinium DTPA , Lymphatic Diseases , Magnetic Resonance Imaging , Ovarian Cysts , Pelvis , Statistics as TopicABSTRACT
Objective To discuss magnetic resonance fat suppression technique,such as Chemical Shift Selective and Short TI Inversion Recovery Sequence,and its clinical value.Methods 73 cases undergoing MRI fat suppression during March 2008 to July 2008 were adopted as the subjects,with such site examined respectively as the skull,basalis,nasopharynx,neck,bones and joints as well as abdominal pelvis.Comparative study of image quality was performed to determine the di-agnostic value of MRI fat suppression technique.Results Of the all cases,7 ones suffered from skull lesions,6 ones from eye diseases,11 ones from abdominal pelvic diseases,4 ones from liver diseases,4 ones from pancreas disorders,and 8 ones from pelvic diseases.Meanwhile,of 10 cases of basalis diseases,there were 8 ones of nasopharyngeal carcinoma and 2 ones of oropharynx disorder.Of 16 cervical disorders,there were 6 ones of neurogenic tumor,3 ones of leucoma,5 ones of metastatic tumor and 2 ones of lipoma.Of 15 cases of vertebral disorders and osteoarthropathia,there were 8 ones of bone contusion,3 ones of metastatic tumor,3 ones of angeioma and 1 case of lipoma.Fat suppression technique,with the lesion edge outlined clearly and the lesions containing adipose tissue identified,provided more information than regular MRI.Conclusion The fat-suppression technique can significantly improve image quality,enhance disease diagnosis rate,and thus is an important technology in MRI examination.