首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Summary Aim of the study: Using phantom studies, a dedicated low-field MR system with 0.2 T and a whole-body MR-scanner with 1.0 T were compared. Methods: A spin-echo sequence was performed on the 0.2-T MR unit using the knee coil and on the 1.0-T MR unit with the head coil. In a water-filled phantom, signal-to-noise ratios (SNR) were calculated and contrast measurements on gels with well-defined relaxation times were obtained and compared to nominal relaxation times. Measurements of T1 and T2 relaxation times on the low-field system were compared to the 1.0-T unit. As a parameter for geometrical image quality, magnetic field distortions were calculated. In theory, influence of field strength and and receiver bandwidth on the minimal echo time and on chemical shift artifacts were calculated. Results: The SNR was 63.2 on the 0.2-T and 179.6 on the 1.0-T MR unit (difference factor 3, against a theoretical difference of 5–16). Relaxation times on the low-field system were significantly (around 40–50 %) lower. Measurements of contrast were similar on both systems. On the low-field system geometrical distortions of several pixels were recorded. The minimal echo time on the low-field system was 21.3 ms with the low receiver bandwidth and 4.3 ms on the 1.0-T MR unit. The amount of chemical shift artefacts was the same on both systems. Discussion: On low-field MR systems SNR is markedly improved by small read-out gradients and a low receiver bandwidth (factor 3 vs 5–16 in comparison with the 1.0-T MR unit). However, an optimal homogeneous magnetic field is required, since inhomogeneities may create severe geometrical distortion.   相似文献   

2.
Summary The purpose of our study was to compare the diagnostic performance of a 0.2-T MRI unit and a 1.0-T MRI unit in the evaluation of the anterior cruciate ligament in patients with clinically suspected lesions of this ligament. Twenty four patients with clinically suspected lesions of the anterior cruciate ligament underwent MRI of the knee on both 0.2-T and 1.0-T MRI units. Three independent observers evaluated the examinations for primary and secondary signs of a tear of the anterior cruciate ligament. Frequency of these signs was determined for both modalities, and observer agreement was assessed using the kappa statistic. Sixteen of 24 patients had signs of tears of the anterior cruciate ligament on the 1.0-T unit; the 0.2-T unit detected primary signs in 15/16 (93 %) patients and secondary signs in 7/12 (43 %) patients. In 8 patients the 1.0 T unit showed neither primary nor secondary signs for tears of the anterior cruciate ligament; in these patients the 0.2-T unit detected primary signs in 1/8 cases (12 %), and secondary signs in 3/8 cases (37 %). Observer agreement was very good for the 1.0-T unit and fair for the 0.2-T unit. There is no substantial difference between 1.0-T units and 0.2-T MRI units in the visualisation of primary signs of tears of the anterior cruciate ligament. In the visualisation of secondary signs, 1.0-T units are superior to 0.2-T units, and there is a surprisingly high rate of false-positive results with the 0.2-T unit. As to the reproducibility of the results, the 1.0-T unit is far superior to the 0.2-T unit.   相似文献   

3.
Punch biopsy or fine needle aspiration biopsy in percutaneous puncture   总被引:6,自引:0,他引:6  
Purpose: The diagnostic accuracy and rate of complications of CT-guided core biopsies (CB) from suspected tumors of the chest were compared to the accuracy a complications of fine-needle aspiration biopsies (FNAB). Methods: The accuracy in the diagnosis of a benign or malignant lesion of 79 FNAB (19.5 G self-aspirating cutting needle) and of 83 CB (18 G automated core biopsy) and the rates of pneumothorax, pleural drainage and hemoptysis were retrospectively evaluated. Results: With FNAB, the sensitivity for malignant lesions was 62.1 % and the accuracy 68.4 %. With CB the sensitivity amounted to 85.9 % and accuracy to 86.7 %. The rate of pneumothorax was 25.3 % following FNAB, with a drainage rate of 5.1 % compared to 19.3 % and 6.0 %, respectively, following CB. The rate of pneumothorax and drainage increased with increasing path length through aerated lung. In advanced emphysema, the pneumothorax rate did not increase; however, in pneumothoraces, pleural drainage was mandatory in 20 % of FNAB and in 100 % of CB. Hemoptysis without any therapeutic consequences occurred in 3.8 % following FNAB and in 6.0 % following CB. Conclusions: With CB diagnostic accuracy can be clearly increased without an obvious increase in the complication rate. However, in patients with obvious emphysema, the pleural drainage rate of pneumothorax may be higher following CB.   相似文献   

4.
Summary Purpose of this study was to evaluate the diagnostic value of a low field dedicated MRI system in hand and wrist imaging. All 308 exams of the hand and wrist, that were performed on a low-field dedicated MRI system (Artoscan, Esaote Biomedica, Italy) in our institution in 1996, and high-field MRI exams performed in addition as part of the diagnostic work-up, were evaluated and correlated to final operative (n = 64) and histologic (n = 12) reports. 90 % of all low-field MRI scans stated a diagnosis according to clinical suspicion. In 62 % the clinical question was answered, and in 26 % additional pathologies were identified. An MR-diagnosis completely different from the clinical suspicion was stated in 2 %. High field exams contributed additional information in 6 of 36 patients. In 3 patients a tumor was not shown completely in the limited field-of-view of the dedicated low-field MRI-system. Frequency-selective fat-suppression pulse sequences and a better spatial resolution were the reasons for the additional information obtained in the other three patients. Low-field dedicated MR-imaging is a valuable method in the extensive work-up of the hand and wrist. Osseous, ligamentous and tendinous pathologies are well depicted. Large or infiltrative tumors should be referred to a high-field system.   相似文献   

5.
Summery The value of macromolecular contrast agents (MMCM) for the characterization of benign and malignant breast tumors will be demonstrated in this review. Animal studies suggest a high potential of MMCM to increase the specificity of MR-mammography. The concept of tumor differentiation is based on the pathological hyperpermeability of microvessels in malignant tumors. MMCM show a leak into the interstitium of carcinomas, whereas they are confined to the intravascular space in benign tumors. Capabilities and limitations of the MMCM-prototype. Albumin-Gd-DTPA, for breast tumor characterization will be summarized and compared to the standard low molecular weight contrast agent Gd-DTPA. Initial experience with new MMCM, such as Dendrimers, Gd-DTPA-Polylysine and MS-325 will be outlined. The potential of “blood-pool“-iron oxides, such as AMI-227 for the evaluation of tumor microvascular permeabilities will be discussed.   相似文献   

6.
Summary Purpose: To determine the value of gadolinium-enhanced, three-dimensional breathhold Magnetic Resonance Angiography (MRA) in the assessment of the aorta and renal arteries in comparison to conventional arteriography (CA). Patients and methods: 49 patients were evaluated with both CA and 3D MRA. 0.3 mmol/kg BW gadolinium-DTPA was administered intravenously in a bolus, using an automated injector. A test bolus method was used for timing of the bolus and beginning of the data acquisition. The intraarterial CA was used as the gold standard. Results: MRA-based assessment of renal artery stenosis was identical with CA in 31 of 45 stenoses (68.8 %). Sensitivity and specificity for assessment of renal arterial disease by MRA were 84 % and 96 %; for clinically relevant lesions they amounted to 90 % and 98 %. Conclusion: The presented contrast-enhanced 3D MRA technique allows for the reliable assessment of renal arterial morphology and pathology.   相似文献   

7.
Purpose. To estimate disease activity in patients with systemic sclerosis using contrast-enhanced MRI of the skin. Material and Methods. In a pre-study, sequences of a low-field (0.2 T) scanner (Artoscan, Esaote, Genova, Italy) were optimized for detection of intravenous contrast (0.1 mmol/l Gd-DTPA) in six patients with the autoimmune disease systemic scleroderma. Based on the results of the pre-study, 17 patients with scleroderma (7 sclerotic/10 active inflammatory disease) were scanned using gradient-spoiled 3D GRE sequences (FA 90 °, TR 100 ms, TE 18 ms), which had been established as most sensitive for intravenous contrast. Contrast enhancement of the skin was determined quantitatively by contrast-to-noise ratios (CNR), comparing post- to pre-contrast and dynamic scans (for 6 min, 1 acquisition/min). Patients in the chronic state with sclerodactylia and active inflammation of the hands were considered separately and compared to a control group (n = 10) matched according to age. Results. CNR increase after intravenous contrast was significantly higher in patients with active disease (86 ± 16 % increase) than sclerosing disease (29 ± 3 %, p < 0.05) and the control group (4 ± 2 %, p < 0.05). The dynamic examination showed a significantly slower decrease after the peak rise in the first minute in patients with active disease (CNR 15.4 ± 0.7 to 14.2 ± 1.4) than in those with chronic disease (14.1 ± 0.5 to 11.3 ± 0.9, p < 0.05). Discussion. Capillary leakage is the most likely explanation for the increased enhancement in patients with active scleroderma. Using sequences optimized for contrast detection, disease activity in the course of scleroderma and response to therapy can be determined by MRI in the future.   相似文献   

8.
Objective. To assess the usefulness of a new axial radiographic technique in knees with patellofemoral arthritis (PF-OA). Design and patients. After a marking wire had been attached to the skin on the tibial tuberosity so that the wire matched the width of the patellar tendon, an axial radiograph was taken at 30° of flexion in 16 normal knees and 14 PF-OA knees in which computed tomographic analysis had revealed a laterally positioned tibial tuberosity at 30° of flexion. The distance of the marking wire from the lateral condyle and from the patellar groove was compared between the two groups. Results. The marking wire was located significantly laterally in PF-OA knees compared with normal knees. Conclusion. An axial radiograph with a marking wire on the tibial tuberosity is useful for assessing the position of the tibial tuberosity in PF-OA knees.  相似文献   

9.
Introduction: Advanced therapies are improving significantly the survival of patients with malignant focal liver disease. For efficient implementation of these surgical and interventional techniques a clear concept of the diagnostic procedere is mandatory. Methods: Based on a review of the current literature, the different imaging modalities, including ultrasound, computed tomography, magnetic resonance tomography, nuclear medicine and angiography, are discussed and evaluated for their diagnostic efficacy in focal hepatic disease. Results: Considering clinical, diagnostic, and economical appropriateness, recommendations for diagnostic strategies in different clinical scenarios regarding focal hepatic disease are presented. Conclusion: If the power of specific imaging methods and relevant clinical information is known, problem-based diagnostic strategies help to avoid unnecessary, expensive and time-consuming studies in the work-up of focal liver lesions.   相似文献   

10.

Purpose:

1) To analyze and compare fast dynamic imaging sequences to biopsy suspect liver lesions. 2) To evaluate the additional use of hepatocyte‐specific contrast agent compared to the nonenhanced fast dynamic scans and diagnostic liver imaging.

Materials and Methods:

Image acquisition was performed using a 1T open‐configured scanner suitable for interventional purposes. Transversal postcontrast T1‐weighted (T1w) fat‐saturated 3D high‐resolution examination (THRIVE) images were acquired >20 minutes postintravenous application of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd‐EOB‐DTPA). A single slice, crossing the level of the lesion, was acquired using intermediate‐weighted steady‐state free‐precession (bTFE), T1w‐gradient echo and spin echo (T1FFE/TSE), T2w‐spin echo (sshTSE) sequences. T1w imaging was acquired prior and after contrast media application. Diagnostic and fast dynamic images were compared based on a 10‐point rating scale. In addition, the liver‐to‐lesion‐contrast ratio was measured.

Results:

A total of 39 malignant lesions with a mean diameter of 13 mm (5–30 mm) in 39 patients were included. Concerning a test of noninferiority, there was no significant difference between rating score values of fast dynamic imaging employing contrast‐enhanced T1FFE‐sequences compared to diagnostic THRIVE (P = 0.001). Calculated liver‐to‐lesion contrast also showed no difference for either imaging sequence (P = 1.0). All other sequences tested showed significant inferiority (P ≤ 0.001).

Conclusion:

T1w Gd‐EOB‐DTPA contrast‐enhanced fast dynamic GRE imaging significantly improves the contrast behavior of malignant liver lesions comparable to diagnostic imaging and is best suited for liver intervention, especially at 1T open magnetic resonance imaging. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.  相似文献   

11.
Summary Purpose: To evaluate the usefulness of magnetic resonance (MR) imaging in the assessment of inconclusive findings at mammography, such as indeterminate focal or diffuse breast abnormalities, post-treatment breasts with extensive scarring, dense breasts, and findings suggesting multifocal or multicentric breast cancer. Material and Methods: 254 patients underwent mammography, sonography, and MRI of the breast. Dynamic MR imaging was done using a thin-section three-dimensional gradient-echo sequence (FLASH, TR = 11.8 ms; TE = 5 ms; flip angle = 25 °) which was applied in a dynamic fashion before and every 90 seconds after injection of gadopentetate dimeglumine. Diagnoses were confirmed at biopsy (n = 165) or by follow-up (n = 89). Results: Among various breast anomalies, the highest proportion of breast cancers was associated with dense breast tissue (27.8 %), architectural distortion (26.9 %), and irregular scars (15.8 %). Sensitivity of dynamic MR imaging was 93.7 %, and specificity was 83.3 %. As compared to mammography and sonography, MR detected 6 occult carcinomas, and showed additional malignant lesions in 19/63 women (30.2 %) with biopsy-proven breast cancer. Conclusion: MR imaging of the breast may provide valuable additional information in indeterminate breast anomalies. However, because of its inherent limitations, it should not replace core needle biopsy in all lesions which are amenable to biopsy. Because of its high sensitivity in the detection of invasive carcinomas in any type of breast tissue, MR imaging is considered the modality of choice in the evaluation of dense breasts in high-risk patients or in patients with clinical suspicion of occult breast cancer, and for preoperative tumor staging.   相似文献   

12.
I. P. Arlart 《Der Radiologe》1997,37(7):554-565
Summary Conventional MR-angiography (MRA) of the abdominal veins is a noninvasive and useful technique that has been accepted in clinical routine. The aim of this presentation is to evaluate the actual status of MRA including contrast-enhanced techniques and to compare clinical results with alternative diagnostic procedures such as ultrasonography, CT, and digital subtraction angiography (DSA). Material and Methods: Four different MRA techniques available today are presented that can be used for examination of the abdominal veins including sequence-parameters of the 2D TOF-FLASH technique, the 2D/3D PC techniques, the 2D True FISP technique, and the ultrafast 3D FLASH technique following i. v. administration of Gd-DTPA. Results: From data of the current literature usefulness and accuracy of MRA is demonstrated in different provinces of the abdominal veins. Discussion: On the basis of specific questions that are focused on MRA of the abdominal veins the value of this method is discussed under consideration of different techniques. MRA is evaluated under consideration of critical vascular areas, the role of contrast-enhanced MRA, suitable doses of contrast material, and new hard-ware configurations in the future. Furthermore, advantages and drawbacks of conventional MRA are compared with contrast-enhanced MRA-techniques, ultrasonography, CT and DSA.   相似文献   

13.
In this article we describe clinical applications of functional MRI (fMRI) at 1.0 T. All experiments were performed on a commercially available 1.0-T system (Magnetom Impact Expert, Siemens AG, Erlangen, Germany) using a blood oxygen level-dependent (BOLD)-sensitive multi-slice EPI technique (TE 66 ms, 4 mm slice thickness, 210 mm field of view, 64 × 64 acquisition matrix). Different paradigms for localization of the motor cortex and for language lateralization were tested in healthy subjects and patients. Methodological considerations concerning the development of the paradigms are also described. In all healthy subjects, motor activation elicited BOLD signal changes in the sensorimotor cortex, permitting identification of primary motor and sensory cortical areas. Furthermore, focal activation of different cortical areas by a language task was possible in 6 of 10 subjects. Nineteen motor studies were performed in 18 patients with supratentorial lesions, in most cases prior to neurosurgical procedures. In 14 studies, fMRI results demonstrated the localization of the motor hand areas relative to the lesion. The results proved valuable for preoperative planning and contributed to therapeutical decisions. We conclude that functional MRI for clinically relevant applications, such as localization of motor and language function, is feasible even at a field strength of 1.0 T without dedicated equipment. Received: 5 May 1998; Revision received: 1 July 1998; Accepted: 13 July 1998  相似文献   

14.
Summary Real bone tumors are rarely encountered in the daily routine of radiological practice. Therefore, for a general radiologist there is no need for a specialist knowledge on this field. However, he should be able to distinguish benign from malignant lesions in order to avoid unnecessary biopsies. A systematic approach towards osteolytic lesions, e. g. according to the classification of Lodwick, is mandatory. CT and MRI are indicated to clear up the anatomy in areas of superposition artefacts in conventional radiology and to determine the inner structure of a lesion, e. g. fatty tissue, liquid/solid. This paper highlights the advantages and disadvantages and the cost-effective use of the imaging modalities including scintigraphy in the diagnosis of bone tumors and tumor-like lesions. Guidelines for the management of bony lesions will be given in detail. The option and necessity for a specialist second opinion is emphasized.   相似文献   

15.
Diagnostic imaging of aortic diseases   总被引:1,自引:0,他引:1  
Summary The aim of this overview is the comparison between noninvasive tomographic imaging modalities such as surface echocardiography, transesophageal echocardiography, X-ray computed tomography and magnetic resonance imaging with the previous gold standard angiography in the setting of acute and chronic aortic diseases. Methods: The groundwork for the comparison between various noninvasive modalities is the validation of findings with angiography or intraoperative and histopathological results. Results and conclusions: Noninvasive modalities such as transesophageal echocardiography, X-ray computed tomography and magnetic resonance imaging are suitable methods for reliable diagnosis or exclusion of aortic dissection both in the ascending and descending segment of the thoracic aorta. Other more rare pathologies of the aorta such as intramural hemorrhage as a precursor of dissection, aortic ulcers, aneurysms as well as congenital and posttraumatic lesions may also be subjected to transesophageal echocardiography or magnetic resonance imaging with excellent sensitivity and specificity; both techniques have also proven to be safe procedures in critically ill patients and have, in our view, replaced angiography for the diagnosis of acute aortic syndromes. Thus, in acute aortic diseases invasive angiographic procedures should be relegated to a complementary role, while transesophageal echocardiography, X-ray computed tomography (especially helical CT) in acute, and magnetic resonance imaging in chronic cases represent prefered diagnostic options. In addition to primary diagnostics the noninvasive approaches using transesophageal echocardiography and magnetic resonance imaging are superbly suitable for serial follow-up imaging in all forms of aortic pathology. Eingegangen am 23. Januar 1997 Angenommen am 23. Januar 1997  相似文献   

16.
The aim of this study was to predict the benign or malignant nature of a prostatic lesion by defining a threshold value of signal intensity ratio and a limiting value of serum prostate-specific antigen (PSA) in patients with elevated PSA level. Twenty-six patients with elevated PSA level and no hypoechogenic lesions at endosonography underwent MR imaging using an endorectal body phased-array coil at 1.5 T (Siemens Magnetom Symphony). A T2-weighted turbo-spin-echo (TSE) pulse sequence was applied in a transverse orientation. Two radiologists evaluated the images. In the presence of a pathological finding they defined regions of interest (ROI) in the suspicious pathological area of the peripheral zone and in muscle for reference. The quotient of the two ROIs was calculated and then correlated with the actual PSA level. Diagnosis was confirmed by prostate biopsy. Ten of 12 patients with quotients smaller than 4 showed cancer at histology. Nine of 12 men with cancer proven by biopsy had PSA levels higher than 10 ng/ml. A significant difference (p < 0.001) was found between the quotients of cancer and quotients of chronic prostatitis, fibrosis, or glandular atrophy. The accuracy of tumor differentiation of the method was 77 %. Measurement of signal intensity quotients in the peripheral zone of the prostate in combination with knowledge of defined limits of PSA levels the technique could be helpful in detecting additional cancer areas for prostate biopsy. False-negative tumor results of standard sextant biopsy can be reduced. In men with high PSA values the method has a role in differentiating between patients who require prostate biopsy and those of clinical observation. Received: 2 February 2000, Revised: 11 May 2000, Accepted: 12 May 2000  相似文献   

17.
The objective of this study was to compare the image quality, sensitivity, specificity, and diagnostic accuracy of an open low-field MR system (0.2 T) with a standard high-field MR system (1.5 T) after arthrography of the shoulder. Thirty-eight patients either with suspected chronic instability (n = 12) or rotator cuff abnormalities (n = 26) were examined. Intra-articular injection of diluted Gd-DTPA was followed in randomized order either first by imaging on an open 0.2-T system or on a 1.5-T system. The image material was evaluated independently by two radiologists in a blinded fashion with respect to overall image quality and the detection of rotator cuff as well as capsular and labral abnormalities. Surgical correlation was available in 27 (71 %) of 38 patients. For both systems, sensitivity and specificity for rotator cuff tears were 100 % each, and for labrum pathologies, these values were 100 and 93 %, respectively. The agreement for detection of labral pathologies between low-field and high-field examinations was good (ϰ = 0.69, ϰ = 0.61). For the detection of full-thickness tears of the rotator cuff, the agreement between the low-field and high-field MR examinations was very good and significant (ϰ = 0.94, ϰ = 1, p < 0.001). Overall image quality was rated good in 17 (45 %) and fair in 21 (55 %) of 38 cases on the 0.2-T MR system, and good in 32 (84 %) and fair in 6 (16 %) of 38 cases on the 1.5-T system. Motion artifacts were considered low in 24 (63 %) and moderate in 14 (37 %) of 38 cases for the 0.2-T system and low in 34 (89 %) and moderate in 4 (11 %) for 1.5-T system. Based on our results, low-field MR compares favorably to high-field MR in the detection of major abnormalities of the glenohumeral joint, at least when MR arthrography is used. Disadvantages are the duration of the examination and thus the risk of reduced image quality caused by motion artifacts. Received: 14 July 1999; Revised: 27 December 1999; Accepted: 27 December 1999  相似文献   

18.
The purpose of this study was to evaluate the safety and precision of MRI-guided biopsies of retroperitoneal space-occupying tumors in an open low-field system. In 30 patients with indistinct retroperitoneal tumors [paraaortic lesion (n=20), kidney (n=2), suprarenal gland (n=3) and pancreas (n=5)] MR-guided biopsies were performed using a low-field system (0.2 T, Magnetom Concerto, Siemens, Germany). For the monitoring of the biopsies T1-weighted FLASH sequences (TR/TE=160/5 ms; 90°) were used in all patients and modified FLASH sequences (TR/TE=160/13 ms; 90°) in ten patients. After positioning of the needle in the tumors 114 biopsy specimens were acquired in coaxial technique with 16-gauge cutting needles (Somatex, Germany). The biopsies were successfully performed in all patients without vascular or organ injuries. The visualization of the aortic blood flow with MRI facilitated the biopsy procedures of paraaortic lesions. The size of the lesions ranged from 1.6 to 7.5 cm. The median distance of the biopsy access path was 10.4 cm. Adequate specimens were obtained in 28 cases (93.3%) resulting in a correct histological classification of 27 lesions (90%). In conclusion, MR-guided biopsies of retroperitoneal lesions using an open low-field system can be performed safely and accurately and is an alternative to CT-guided biopsies.  相似文献   

19.
Summary Purpose: Debate about the potential implementation of Spiral-CT in diagnostic algorithms of pulmonary embolism are often focussed on sensitivity and specificity in the context of comparative methodologic studies. We intend to investigate whether additional factors might influence this debate. Materials and methods: On the basis of the current literature and of own experience we study the influence of factors such as availability, acceptance, patient-outcome, and cost effectiveness-studies on the potential implementation of Spiral-CT in diagnostic algorithms of pulmonary embolism. This information is analyzed together with data from comparative methodologic studies. Results: The factors availability, acceptance, patient-outcome, and cost-effectiveness-studies do have substantial influence on the implementation of Spiral-CT in the diagnostic algorithms of pulmonary embolism. Incorporation of these factors into the discussion might lead to more flexible and more patient-oriented algorithms for the diagnosis of pulmonary embolism. Conclusion: Availability of equipment, acceptance among clinicians, patient-outcome, and cost-effectiveness evaluations should be implemented into the debate about potential implementation of Spiral-CT in routine diagnostic imaging algorithms of pulmonary embolism.   相似文献   

20.
Summary Forty-one patients demonstrating clinical symptoms for cerebral infarction were investigated by magnetic resonance imaging with diffusion-weighted echo-planar imaging (DWI) and T2-weighted imaging (T2WI). In 8 patients only DWI showed the cerebral lesions clearly. One patient with positive DWI and T2WI suffered from HSV encephalitis. DWI is superior to T2WI in assessment of small cortical infarcts and cerebral infarction in patients with preexisting vascular lesions. DWI is not specific, so other causes like cerebral hematoma and encephalitis have to be considered.   相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号