| Background and objectionMagnetic resonance enhanced lesions is often due to local blood volume or blood flow relative increase and/or lack of blood brain barrier or blood brain barrier is broken resulting in abnormal permeability increase and local vascular dysplasia, contrast agent extravasation induced. According to the findings of magnetic resonance imaging, enhancement mode is divided into homogenous,heterogenous, patchy and diffuse,cotton-ball,nodular,punctate, open ring and multiple closed rings.Typical ring enhanced lesions include open ring and closed ring,the lesions may involve the gray matter, gray matter and deep white matter junction. As the development of the imaging technology,the detection and incidence rate of the ring enhanced lesions constantly improving,the more realized to the disease and the average life expectancy, it is to be important to improve the cognition of clinicians on this kind of disease to do early diagnosis and treatment.Cranial magnetic resonance imaging technique is an important means for the detection of intracranial lesions, and conventional MRI sequences include T1WI and T2WI.Conventional imaging sequence is easy to ignore small, concealed and special parts of the lesions, is unable to analyza lesion types,etiology, prognosis, for non developing lessions in the conventional radiographic imaging could easily lead to misdiagnosis,delay the timing of treatment, resulting in misdiagnosis,missed diagnosis and affect the prognosis of the disease. With the development of imaging technology, Diffusion Weighted Imaging,Fluid Attenuated Inversion Recovery, Perfusion Weighted Imaging,Magnetic Resonance Spectroscopy and other new imaging technology is becoming more and more perfect. Relative to conventional magnetic resonance imaging, the new imaging technology can better observe thelesion,for example DWI can better observe the internal water molecules in the living tissues diffusion; flair sequences can better observe the adjacent cerebrospinal fluid, with hyperintensity (T2) lesions can be clearly displayed;MRS can determine the chemical composition of a specific tissue in a living body.Using a variety of new imaging techniques, it has solved the problem of the analysis of the type of lesion,the detection rate of the non developing and occult lesions,It provides important imaging evidence for the diagnosis and differential diagnosis of the disease.lt provides an important basis for the clinical for diagnosis.With the continuous development of the new techniques of neuroimaging, the detection rate of abnormal lesions is increasing, and the common imaging findings of abnormal nervous system are the ring enhanced lesions.Multiple causes can lead to ring enhanced lesions,in the normal immune function patients with high or low incidence of this disease is glioma, intracranial metastases, infectious diseases, demyelinating disease, benign tumor.In immunosuppressed patients or organ transplantation for is toxoplasmosis, primary central nervous system lymphoma, fungal infection. Because the causes of disease are different,the treatment and prognosis are often very different, the distinguish between neoplastic lesions and non neoplastic lesions, primary tumors and secondary tumors, infectious disease etiology is very important.Once the misdiagnosis causes unnecessary surgical treatment, toxic chemical therapy or even lead to radiation damage.Biopsy although is the gold standard for diagnosis of the disease, but due to the domestic situation, not all patients underwent biopsy, so noninvasive magnetic resonance examination to become a very important method of examination.At present, advanced magnetic resonance imaging technology, DWI, ADC-map, MRS can provide important evidence for the diagnosis of disease.lt has provided an important basis for early diagnosis,treatment and evaluation of treatment effect of the disease, and greatly shorten the time to diagnose the disease, according to the characteristics of magnetic resonance ring enhanced lesions. At present, there are some reports on the magnetic resonance DWI and MRS imaging features of brain abscess, intracranial glioma, the disease of the brain, and Toxoplasma gondii.Because the varied etiology of the ring enhanced lesions, and most of them the focus of a disease can exist in different diseases co-occurrence or treating the same disease with different imaging, resulting in most clinicians do not have a clear understanding of thses disease image features, especially when the lesion characteristics is not obvious. In this paper, according to the ring wall, we divided lesion into three parts the ring wall,internal part and external part to discuss, summarize the imaging features of ring wall,internal part and external part,and further analysis of the important value of enhanced lesion characteristics to provide more evidence for clinical treatment, select the appropriate treatment options.MATERIALS AND METHODS1.Case dataFrom January 2015 to December, in the Nanfang Hospital of Southern Medical University, all patients underwent MR enhancement scan showed ring enhancement or open ring enhancement.All patients were confirmed by pathology or clinical diagnosis. Exclude the diagnosis is not clear or the information is not complete. Postoperative patient were excluded.2.MRI checkMagnetic resonance imaging using 3.0T superconducting magnetic resonance scanner, head surface coil, conventional line Tlflair, FrfseT2WI and coronal T2flair scan, sagittal and axial T1 flair enhanced scanning. Diffusion weighted imaging (DWI) using the words stimulated echo planar spin echo sequence and b values of 0 and 1000s/mm,1H-MRS scanning in Flair/T2WI or enhanced T1WI position, choose maximum level of the tumor as MRS position level, through the software package: chemical shift spectrum diagram, metabolism diagram and metabolism -anatomy diagram four graphics.On the metabolic map, the minimal region of interest is placed in the cavity, the capsule wall and the normal tissue to get the diagram.3.Image analysis and measurementThe lesion area is defined as high,isointensity,low signal in contrast to the contralateral brain tissue or cerebrospinal fluid is by two radiologists.4.MRI signs analysisLesion General character:1,number, location, size, shape, sharpness, peripheral edema ratio; 2,cystic degeneration, hemorrhage and necrosis;3,the cyst wall was complete degree, thickness analysis,outer and inner wall whether smooth;4,lesion were divided into three parts the ring wall,internal part and external part to discuss, summarize the imaging features of T1WI, T2WI, DWI, flair and ADC-map; 5,1H-MRS analysis,Lesions and contralateral normal tissue were compared.5.Data processingUsing software SPSS 20 for statistical analysis.Descriptive statistical analysis of age, sex, location and number of lesions.Area, length, width, age, using one way ANOVA.When the variance is homogeneous, the LSD method is used to Post Hoc Multiple Comparisons,When the variance is not homogeneous, the T3 Dunnett method is used to Post Hoc Multiple Comparisons.P>0.05 believes that there is statistical difference.ResultFrom January 2015 to December, in the Nanfang Hospital of Southern Medical University, all patients underwent MR enhancement scan showed ring enhancement or open ring enhancement.All patients were confirmed by pathology or clinical diagnosis,178 cases,396 lesions were collected.According to the onset rate from high to low are metastatic tumor (n=88) 49.7% and glioma (n=33) 18.4% and benign tumors (n=20) 10.6%, central nervous system lymphoma (n=11) 6.7%, brain abscess (n=9) 5.05%, tuberculoma (n=7) 3.9%, demyelination (n=6) 3.35%, parasites (n=4) 2.2%.The average age of the patients was different,Metastatic tumors were found in elderly patients, the average age was 56 years.There was statistical significance (P<0.05), and there was no statistical difference in the incidence of other diseases. There were differences in gender and number of lesions, but there was no significant difference between them.1.The characteristics of the enhanced lesions in 178 patients4 parasite cases,3 cases (3/4) located in supratentorial,1 case were widely distributed,a total of 7 lesions;all lesions showed round shape, clear boundaries,grade III edema,the diameter (0.66±0.18) cm.33 Glioma cases, Which most (28/33) showed single ring enhanced lesions,5 cases showed multiple ring enhanced lesions, lesions can be located in the supratentorial and infratentorial, a total of 38 lesions; most (23/38) lesions showed irregular shape,mild to moderate edema, unclear boundaries, the diameter (4.1±2.1) cm.7 tuberculoma cases,4 cases (4/7) widely distributed,3 cases (3/7) is located in subtentorial, a total of 11 lesions; most (6/11) showed round shape,11 cases showed clear boundaries and severe edema, the diameter (0.98±0.42)cm.20 benign tumor cases, most (18/20) for single ring enhanced lesions, located in supratentorial, a total of 33 lesions; the majority (28/33) lesions showed clear boundaries, round shape and mild to moderate edema,the diameter (2.5±1.15) cm.11 lymphoma cases, most (10/11) for single ring enhancing lesions located in supratentorial,, a total of 18 lesions; the majority (13/18) lesions showed clear boundaries, half forround shape, half for irregular shape, the majority (12/18) lesions with mild to moderate edema,the diameter (2.53±1.15) cm.9 AB cases, the majority (8/9) showed single ring enhanced lesions located in supratentorial, a total of 14 lesions, most lesions showed clear boundaries,round shape and severe edema, the diameter (2.37±1.25) cm.6 demyelinating cases, most (5/6) for single ring enhancing lesions located in supratentorial,1 cases widely distributed, a total of 10 lesions, and most (7/10) lesion showed round, clear boundaries, and varied edema,the diameter (1.4±0.93) cm.88 metastatic tumors cases,31 cases (31/88) lesions of multiple distributed, a total of 265 lesions; the majority (237/265) showed round, boundaries clear, and mild to moderate edema,the diameter (1.45±1.21) cm.Glioma,lymphoma is well sent on the supratentoial, Accidental in supratentoial, usually a single lesion.there is statistical significance.The length and area of the lesion were statistically analyzed,the parasites and the tuberculoma were small, the gliomas and benign tumors were large, and the demyelination were small to medium size.Metastatic tumors, brain abscess, and lymphoma were varied in size, mostly lesons were medium or small size,Lesion diameter and area of different sizes have statistical significance.There were statistical differences between the parasitic lesions and other diseases, and the brain abscess and the tuberculoma were Ⅱ～Ⅲ level edema,there was no statistical difference, and other diseases were different according to different stages of edema.2.Lesions accompanied by the phenomenonParasitic lesions without cystic degeneration, hemorrhage and necrosis,Gliomas 6 lesions with cystic degeneration;benign tumour 6 lesions with cystic degeneration,2 lesions with hemorrhage, and 4 lesions with necrosis;Brain abscesses 3 lesions with cystic degeneration,1 lesions with necrosis;metastases 10 lesions with cystic degeneration, 18 lesions with hemorrhage,6 lesions with necrosis;lymphoma 1 lesions with hemorrhage.5 lesions with necrosis;demyelination 3 lesions with necrosis.Parasitic lesions without cystic degeneration, hemorrhage and necrosis,lymphoma,demyelination without cystic degeneration;Gliomas,benign tumour lesions always with cystic degeneration, hemorrhage and necrosis;But whether there is statistical difference, need to be further discussed.3.wall analysis7 Parasites lesions with closed ring enhaced wall, most (6/7) showed thin wall, smooth inner and outer wall.38 Glioma lesions, most (31/38) with complete ring wall, and majority (25/38) showed uneven thick wall, rough internal and external wall.11 Tuberculoma lesions, all with complete ring wall the majority (8/11) for thin wall, rough inner and outer wall.33 Benign tumor lesions, most (22/33)with complete ring wall, most (25/33) for uneven thick wall,most (n≥24)with rough inner and outer wall.18 Lymphoma lesions, most (11/18) with complete wall, most (15/18) with uneven thick wall, rough inner and outer wall.14 AB lesions, all lesions with complete ring wall, majority(9/14) with thinwall, the majority (11/14) with smooth inter and outer wall.10 Demyelinating lesions, most (7/10) with complete wall, part (3/10) with open ring wall, most with thin, and rough inter and outer wall.265 Metastases lesions, most (n=252) with complete and uneven thick wall, most (n=192) with rough inter and outer wall.4.TIWI, T2WI, DWI, Flair, ADC-map signal characteristicsAll Parasite lesions showed long TI long T2 signal, the wall showed high DWI signal and low ADC signal;the internal and external showed low DWI and high ADC signal.38 Glioma lesions,most showed long T1 long T2 signal,the wall most (25/38) showed high DWI and low ADC signal; the internal part most (26/38) showed low DWI and high ADC signal, and the external most (30/38) showed isointensity signal.11Tuberculoma lesions,the internal and external showed long T1 long T2 signal,the wall partly (6/11) showed long T1 long T2 signal, partly (6/11) showed long T1 isointensity T2 signal.The wall most (9/11) showed isointensity DWI signal,the internal and external showed low DWI signal.The wall partly (2/4) showed isointensity ADC signal and partly low signal,the internal showed high ADC signal,the external showed low and isotntensity DWI signal.33 Benign tumor lesions, most(28/33) showed long T1 long T2 signal.The wall most (23/33) showed high DWI and low ADC signal.The internal most(17/33)showed low DWI and high ADC signal,the external most(27/33)showed isointensity DWI and high ADC signal.18 CNS lymphoma lesions,most(15/18) showed long T1 long T2 signal high Flair signal.The wall most (13/18) showed high DWI and isointensity ADC signal.The internal showed low or gihg DWI signal and most (4/5)showed high ADC signal,the external most(11/18)showed isointensity DWI and most (4/5)high ADC signal.14 AB lesions,the internal and external most(11/14) showed long T1 long T2 signal.The wall partly(5/14) showed isointensity T1 long T2 signal,part(7/14)showed long T1 long T2 signal,a few showed short T1signal.The wall most(9/14) showed low Flair signal,most (11/14)showed high DWI signal;the internal most (11/14) showed high DWI and external show isointensity DWI signal.On ADC-map,the wall(2/3) showed isointensity signal, the internal showed high ADC signal,the external showed high ADC signal.10 Demyelinating lesions,the wall and internal most (7/10)showed long T1 long T2 signal,the external most(6/10)showed isointensity T1 long T2 signal.The wall most(6/10)showed high DWI signal,the internal showed low signal,the external showed isointensity signal.On ADC-map,the wall showed low signal,the internal showed high signal,the external showed high signal.265 Metastases lesions,most (n≥178) showed long T1 long T2 high Flair signal.The wall most(206/265)showed high DWI,the internal showed low DWI signal,the external showed isointensity signal.On ADC-map,The wall most (31/48) showed low-isointensity signal,the internal most(34/48) showed high signal,the external most (34/48) showed high signal.On T1WI, T2WI, Flair imaging the wall,the internal and the external showed long -isointensity T1 signal,long-short T2 signal,low-high Flair signal,no significant statistical difference.On DWI sequence, the internal part of the parasite showed low signal, the wall showed high signal, and the external showed low-isointensity signal;Tuberculoma wall showed isointensity signal;the wall and the external part of demyelinating showed isointensity-high signal;the internal part of brain abscess showed low signal or high signal,the external showed high signal, and others are changefull, no significant statistical significance.On ADC-map,the externalof parasites, brain abscess showed high signal；the external of tuberculosis, benign tumor, lymphoma, metastatic tumor showed isointensity-high signal;the external of demyelinating showed isointensity signal;the wall of lymphoma showed isointensity signal;the wall of parasites and demyelinating showed low signal;the wall of abscess and tuberculosis showed isointensity signal,Signal in the rest of the lesion was not statistically significant.5. MRS analysis of lesionsOn 1H-MRS,compared with the normal tissue, the wall of glioma showed NAA and Cr peek were significantly decreased, Cho peak was significantly increased, the ratio of NAA/Cr was decreased, the ratio of Cho/Cr and Cho/NAA were increased, and lip and lac peek were found in the lesion. NAA, Cr peak of CNSL were decreased, Cho peak was increased.NAA peak was decreased of Metastasis tumor,and the Cho peak and the ratio were variable.Because the lesions of the parasite and the tuberculosis are too small to be analyzed and measured.ConclusionThe proportion of intracranial ring enhanced lesions from high to low respectively:metastases, glioma, benign tumor, lymphoma, brain abscess, tuberculosis, demyelination, sparganosis.1, metastatic tumor mostly occured in older patients,located in gray white matter junction area, mostly were multiple ring enhanced lesions, showed small, clear boundaries. MRS showed decreased NAA peak, visible lip peak.2, Glioma lovely occured in hemispheres,involved in corpus callosum, which showed unclear boundaries, irregular shape with occupying effect, accompanied by cystic, hemorrhage, necrosis.The closed enhancement can be uneven thick wall.The most specific finding on MRS were increased lipsd peak, decreased NAA, Cr peak, increased Cho peak.3, Benign tumors were mostly single ring-enchanced lesion located in supratentorial, showed larger,clear boundaries, round shape,with occupying effect, accompanied by cystic degeneration, hemorrhage, necrosis.The closed enhancement can can be seen aneven thick wall. The wall on MRS showed decreased NAA, Cr peak, increased Cho peak.4,CNS lymphoma were mostly single ring-enchanced lesion located in supratentorial, which can involve the basal ganglia, corpus callosum, tumor ependymal spread, showed medium size, clear boundaries, with mild to moderate edema. The closed enhancement showed uneven thick wall. The MRS showed increased Cho, NAA, decreased Cr peak, the increased ratio of Cho/Cr, increased lip peak.5,AB were mostly single ring-enchanced lesion located in supratentorial, showed medium size, clear boundaries, round shape, with mild to moderate edema, can be accompanied by satellite lesions. The internal showed high DWI signal, low ADC-map signal.Contrast enhancement showed closed wall with thin wall, On MRS,the lesions showed decreased NAA, Cho peak, with specific AA, lip lac peak.6,Tuberculosis located subtentorial or widely disseminate, often involved cranial base, showed small, clear boundaries, round shape,with or without meningitis. The wall showed insointensity DWI signal, high ADC-map.The internal showed insointensity-low DWI signal, high ADC-map signal.Contrast enhancement showed closed,uneven thin wall.7, Demyelination were located in supratentorial,showed small, clear boundaries, with mild to moderate edema.MS showed "right angle", "open ring reinforcement". Contrasr enchanced the enhancement scanning is the thin wall open ring enhancement, the MRS visible NAA peak is reduced, the Cho peak is increased, partly visible lip peak.8, Sparganum were multiple lesions located in supratentorial,showed small, clear boundaries, had characteristic "tunnel syndrome", and "focal transmigration ".Different disease stages exist in the same level. Contrast enhancement showed complete thin enhancement. |
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