MRI of fat necrosis of the breast: the "black hole" sign at short tau inversion recovery

Objective

To describe MRI features of fat necrosis of the breast.

Materials and methods

Twenty-five lesions in 16 patients were retrospectively analyzed. MRI was performed due to equivocal findings at conventional imaging after surgical treatment of cancer (n = 14) or during anticoagulant therapy (n = 1), after focal mastitis treated with ductal resection (n = 1). In the 15 patients with previous surgery MRI was performed after a median interval of 24 months, using short tau inversion recovery (STIR) and contrast-enhanced dynamic T1-weighted sequences. Signal-to-noise ratio (SNR) inside the lesion and surrounding healthy fat was calculated on both STIR and unenhanced T1-weighted images. Maximal lesion diameter was measured on STIR images. All lesions had final clinical and imaging assessment in favor of fat necrosis and negative clinical and imaging follow-up (21–40 months; median 24 months).

Results

At STIR sequence, fat necrosis appeared as a “black hole”, being markedly hypointense (median SNR = 29) compared with surrounding fat (median SNR = 95) (P < 0.001), while no significant difference was found at unenhanced T1-weighted sequence. No significant correlation with time from treatment was found. Of 25 lesions, 15 showed ring enhancement, with continuous increase (n = 10), plateau (n = 2), or wash-out curve (n = 3). The 11 enhancing lesions in the 8 patients with previous radiation therapy showed an initial enhancement higher than that of the 4 enhancing lesions in the 2 patients who did not, although the difference was not significant (P = 0.104).

Conclusion

Fat necrosis of the breast exhibits a “black hole” sign on STIR images, allowing for an easier diagnosis in clinical practice.     

腕三角纤维软骨盘损伤：STIR序列诊断与关节镜对照

目的探讨应用短反转时间反转恢复（STIR）序列对腕三角纤维软骨盘(TFC)损伤的诊断价值,并与腕关节镜检查结果进行对照研究。资料与方法对56例临床诊断腕TFC损伤病人应用STIR序列进行腕关节MRI检查及关节镜探查。STIR序列扫描参数采用：TR：l 164 ms,TE：16 ms,TI：90 ms。以关节镜下TFC损伤的探查结果为标准,评价STIR序列诊断TFC损伤的敏感度、特异度、阳性预测值、阴性预测值及准确度。结果①STIR序列显示TFC正常10例;体部内小水肿或黏液样变性,但关节面缘光滑6例;体部水平撕裂,但未累及至关节面缘6例;关节面缘撕裂6例;中央部穿孔11例;桡骨附着端撕裂6例;尺骨附着端撕裂5例;尺、桡骨附着端均撕裂3例;整体形态不规则变薄3例。②关节镜下显示TFC正常21例;表面撕裂8例;中央部穿孔10例;桡骨附着端撕裂7例;尺骨附着端撕裂5例;尺、桡骨附着端均撕裂2例;整体形态不规则变薄3例。以关节镜为标准,STIR序列诊断TFC 损伤的敏感度为85.7%,特异度23.8%,阳性预测值为65.2%,阴性预测值50%,准确度为62.5%。结论STIR序列对TFC损伤具有较高的诊断价值。     

Magnetic resonance separation imaging using a divided inversion recovery technique (DIRT)

The divided inversion recovery technique is an MRI separation method based on tissue T₁ relaxation differences. When tissue T₁ relaxation times are longer than the time between inversion pulses in a segmented inversion recovery pulse sequence, longitudinal magnetization does not pass through the null point. Prior to additional inversion pulses, longitudinal magnetization may have an opposite polarity. Spatial displacement of tissues in inversion recovery balanced steady‐state free‐precession imaging has been shown to be due to this magnetization phase change resulting from incomplete magnetization recovery. In this paper, it is shown how this phase change can be used to provide image separation. A pulse sequence parameter, the time between inversion pulses (T180), can be adjusted to provide water‐fat or fluid separation. Example water‐fat and fluid separation images of the head, heart, and abdomen are presented. The water‐fat separation performance was investigated by comparing image intensities in short‐axis divided inversion recovery technique images of the heart. Fat, blood, and fluid signal was suppressed to the background noise level. Additionally, the separation performance was not affected by main magnetic field inhomogeneities. Magn Reson Med 63:1007–1014, 2010. © 2010 Wiley‐Liss, Inc.     

椎基底动脉延长扩张症的FLAIR影像分析

目的：探讨在椎基底动脉延长扩张症（VBD）患者 FLAIR 序列中血管高信号征（FVH）的特征及其意义。方法：2011年1月－2015年4月本院确诊的49例 VBD 患者,所有患者均行 MRI 常规检查及 TOF-MRA 检查,按照临床表现分为后循环缺血组（18例）及非后循环缺血组（31例）,比较两组临床资料及影像表现的差异,并分析 FVH 征的临床意义。结果：49例 VBD 患者中,36例（73．5％）血管 FVH 征阳性。其中,22例（44．9％）表现为1级,11例表现为2级（22．4％）,3例（6．1％）表现为3级,后循环缺血组 FVH 评分较高者（2或3级）的构成比显著高于非后循环缺血组（55．6％ vs 12．9％,χ2＝11．493,P ＝0．009）。VBD 患者的 FVH 分级与基底动脉（BA）直径、长度及 BA 横向偏移之间具有低度相关性（r＝0．473,P ＝0．001;r＝0．483,P ＜0．001;r＝0．542,P ＜0．001）。结论：VBD 患者 FVH 征阳性率高,其形成机制可能与 BA 血流缓慢有关,且高级别 FVH（2或3级）的出现可以提示 VBD 患者发生后循环缺血的可能性较大。     

T1-Weighted MR imaging of the brain using a fast inversion recovery pulse sequence

The purpose of this paper was to develop and evaluate a fast inversion recovery (FIR) technique for T1-weighted MR imaging of contrast-enhancing brain pathology. The FIR technique was developed, capable of imaging 24 sections in approximately 7 minutes using two echoes per repetition and an alternating echo phase encoding assignment. Resulting images were compared with conventional T1-weighted spin echo (T1SE) images in 18 consecutive patients. Compared with corresponding T1SE images, FIR images were quantitatively comparable or superior for lesion-to-background contrast and contrast-to-noise ratio (CNR). Gray-to-white matter and cerebrospinal fluid (CSF)-to-white matter contrast and CNR were statistically superior in FIR images. Qualitatively, the FIR technique provided comparable lesion detection, improved lesion conspicuity, and superior image contrast compared with T1SE images. Although FIR images had greater amounts of image artifacts, there was not a statistically increased amount of interpretation-interfering image artifact. FIR provides T1-weighted images that are superior to T1SE images for a number of image quality criteria.     

Optic nerve injury demonstrated by MRI with STIR sequences

We studied nine patients with optic nerve injury associated with closed head trauma by magnetic resonance imaging (MRI) with short inversion time inversion recovery (STIR) sequences on 11 occasions from 4 days to 14 years after the injury: three studies were within 17 days and eight over 4 months to 14 years. MRI revealed abnormal high signal in 10 of the 11 injured nerves. MRI 4 days after the injury showed no abnormality.     

Magnetic resonance imaging findings of vulvar epithelioid sarcoma

We describe here a case of vulvar epithelioid sarcoma. Epithelioid sarcoma is a malignant appendicular skin tumor that is rarely of vulvar origin. Magnetic resonance imaging (MRI) revealed a solid mass with an ulcer-like lesion and multilobulated contour. To our knowledge, this is the first case of vulvar epithelioid sarcoma described in the MRI literature.     

磁共振成像短时间反转恢复序列在鼻咽癌中的应用

目的　比较磁共振成像短时间反转恢复序列 (short tauinversionrecovery ,STIR)与快速自旋回波T2加权 (fastspinechoT2weightedimaging ,FSET2WI)在鼻咽癌成像中的应用。方法　 5 0例经手术和病理证实的鼻咽癌病人进行磁共振STIR序列和FSET2WI扫描 ,对两者进行对比度 噪音比值 (C Ns)比较和肿瘤影像征像 (包括肿块边界和肿块内部细节 )清晰程度的比较。结果　STIR序列的C Ns为 2 0 4 1± 3 87,FSET2WI的C Ns为 8 2 4± 1 74。STIR序列比FSET2WI有更高的C Ns ,t=2 0 2 9,P <0 0 1。STIR序列成像对鼻咽癌的边界和内部结构的显示比FSET2WI成像更清楚 ,两者影像征像比较 :鼻咽癌肿块边界 χ2 =2 3 19,P <0 0 1、肿块内部细节 χ2 =16 2 3,P <0 0 1。结论STIR序列在鼻咽癌成像效果比FSET2WI更敏感、更能有效显示鼻咽癌。     

3.0T MR双反转恢复序列在海马硬化诊断中的应用价值

目的 探讨3.0 T MR双反转恢复(DIR)序列在海马硬化(HS)诊断中的价值,分析DIR显示HS患者海马信号强度升高的能力.方法 回顾性分析12例单侧HS患者和12名健康志愿者的临床和影像资料,所有受试者均采用3.0 T MR行斜冠状面DIR、液体衰减反转恢复(FLAIR)序列和快速自旋回波(TSE)序列检查;分别在病变侧与对侧海马结构设置ROI,计算病变侧、对侧及正常对照组海马的相对信号强度,以及病灶的信噪比(SNR)、对比噪声比(CNR)、信号强度比(RSI)和不对称指数(AI),比较3种序列之间各评价指标有无差异.统计学处理采用单因素方差分析.结果 病侧海马于DIR上呈极高信号,病变侧、对侧及正常对照组海马相对信号强度分别为1.50±0.05、1.26±0.03、1.18±0.05,3者间差异有统计学意义(F=172.609,P=0.000).DIR、FLAIR、T2 TSE序列上的病侧海马SNR分别为84.13±16.62、50.90±12.38、63.25±15.46,3者间差异有统计学意义(F=15.185,P=0.000);海马CNR分别为13.72±3.73、6.67±3.02、7.33±3.65,3者间差异有统计学意义(F=14.985,P=0.000);3种序列之间两侧海马的RSI、AI差异均无统计学意义(P值均为0.078).结论 HS于DIR序列上呈特征性的极高信号,DIR图像显示HS的SNR和CNR优于常规MRI序列,其对HS的诊断具有一定价值.

Abstract：

Objective To investigate the imaging feature of hippocampal sclerosis (HS), and evaluate the diagnostic value of double inversion recovery (DIR) sequence at 3.0 T MR for its diagnosis. Methods Twelve patients with unilateral HS proven by pathology and 12 healthy volunteers were enrolled. All patients received DIR, fluid attenuated inversion recovery (FLAIR) and T2 TSE sequences scans on oblique coronal plane vertical to the hippocampal axis on a 3.0 T MR scanner. Regions of interest (ROI) were set respectively in ipsilateral and contralateral hippocampi hippocampi in patients with HS, and the bilateral hippocampi in healthy volunteneers were placed respectively. Signal to noise ratio (SNR), contrast to noise ratio (CNR), ratio of signal intensity (RSI) and asymmetry index (AI) of each ROI in all hippocampi were calculated and compared among the three sequences. Statistical analysis was performed with one-way ANOVA. Results On DIR images, ipsilateral hippocampal lesions demonstrated extremely high signal intensity. Relative signal intensity of ipsilateral hippocampal lesions, contralateral hippocampi and the hippocampi in control groups healthy volunteneers were 1.50±0.05, 1.26±0.03, 1.18±0.05 (F=172.609,P=0.000), respectively. SNR of ipsilateral hippocampal lesions on DIR, FLAIR and T2 TSE sequences were 84.13±16.62, 50.90±12.38, 63.25±15.46 (F=15.185,P=0.000), respectively. CNR of hippocampus were 13.72±3.73, 6.67±3.02, 7.33±3.65 (F=14.985,P=0.000), respectively.In HS patients, RSI and AI of the ipsilateral hippocampal lesions and contralateral hippocampi among the three sequences did not show statistically significant difference(P=0.078). Conclusions HS manifests extremely high signal intensity on DIR images. On DIR images, the SNR and CNR of HS were higher than those on conventional MR sequences which provide valuable information for the diagnosis of HS.     

High-resolution and functional magnetic resonance imaging of the brachial plexus using an isotropic 3D T2 STIR (Short Term Inversion Recovery) SPACE sequence and diffusion tensor imaging

This technical note demonstrates the relevance of the isotropic 3D T2 turbo-spin-echo (TSE) sequence with short-term inversion recovery (STIR) and variable flip angle RF excitations (SPACE: Sampling Perfection with Application optimized Contrasts using different flip angle Evolutions) for high-resolution brachial plexus imaging. The sequence was used in 11 patients in the diagnosis of brachial plexus pathologies involving primary and secondary tumors, and in six volunteers. We show that 3D STIR imaging is not only a reliable alternative to 2D STIR imaging, but it also better evaluates the anatomy, nerve site compression and pathology of the plexus, especially to depict space-occupying tumors along its course. Finally, due to its appropriate contrast we describe how 3D-STIR can be used as a high-resolution mask to be fused with fraction of anisotropy (FA) maps calculated from diffusion tensor imaging (DTI) data of the plexus.     

Magnetic resonance imaging findings of extrapelvic endometriosis of the round ligament

A 31-year-old woman presented with a mass in her groin accompanied by intense pain during the menstrual period. A poorly circumscribed, elastic, hard mass was palpable in her right inguinal region. Magnetic resonance imaging showed that the mass had continuity with the inguinal course of the round ligament of the uterus. The mass lesion was well enhanced with high intensity on diffusion-weighted imaging. An operation was performed, and the histological diagnosis was endometriosis of the round ligament. After operation, she was completely relieved of pain. It is important to include endometriosis in the differential diagnosis in women with painful inguinal mass lesions at risk for endometriosis.     

Magnetic resonance imaging (MRI) of diastematomyelia

Summary The MRI-features of diastematomyelia in a patient with unusually late onset of symptoms are reported. Direct visualization of the split cord and low conus on frontal MR-images was facilitated by three-dimensional Fourier transform (3-DFT) image acquisition.     

A new approach towards improved visualization of myocardial edema using T2-weighted imaging: a cardiovascular magnetic resonance (CMR) study

Purpose:

To compare T2‐weighted cardiovascular magnetic resonance (CMR) imaging with AASPIR (asymmetric adiabatic spectral inversion recovery) and STIR (short T1 inversion recovery) for myocardial signal intensity, image quality, and fat suppression.

Materials and Methods:

Forty consecutive patients (47 ± 16 years old) referred by cardiologists for CMR‐based myocardial tissue characterization were scanned with both STIR and AASPIR T2‐weighted imaging approaches. Signal intensity of left ventricular myocardium was normalized to a region of interest generating a signal‐to‐noise ratio (SNR). In six patients with regional edema on STIR the contrast‐to‐noise ratio (CNR) was assessed. Two independent observers used a scoring system to evaluate image quality and artifact suppression. Six healthy volunteers (three males, 32 ± 7 years) were recruited to compare fat suppression between AASPIR and STIR.

Results:

SNR of AASPIR was greater than STIR for basal (128 ± 44 vs. 83 ± 40, P < 0.001), mid‐ (144 ± 65 vs. 96 ± 39, P < 0.01), and apical (145 ± 59 vs. 105 ± 35, P < 0.05) myocardium. Improved image quality and greater suppression of artifacts was demonstrated with AASPIR. In patients with regional edema, CNR increased by 49% with AASPIR, while SNR of pericardial fat did not differ (44 ± 39 vs. 33 ± 30, P > 0.05).

Conclusion:

Our findings support the implementation of an AASPIR‐based approach for T2‐weighted imaging due to improved pericardial fat suppression, image quality, and artifact suppression with greater CNR and SNR. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.     

Magnetic resonance imaging findings of endometrioid adenocarcinoma of the ovary

PURPOSE: We assessed magnetic resonance imaging (MRI) features and clinical characteristics of ovarian endometrioid adenocarcinoma. MATERIALS AND METHODS: A total of 31 patients with 39 surgically proven ovarian endometrioid adenocarcinomas were analyzed retrospectively. Histologically, 13 lesions in 12 patients arose from proven endometriomas (group A), and 26 lesions in 19 patients did not coexist with endometrioma (group B). The morphological pattern of the lesion on MRI was classified as a solid or a cystic type: A solid type was defined as a solid component occupying more than half of the lesion; and a cystic type was a cystic lesion with one or more mural nodules. RESULTS: Altogether, 11 lesions in group A were the cystic type on MRI, whereas 24 lesions in group B were the solid type (P < 0.0001). Among the 11 cystic-type lesions in group A, the cysts of 5 lesions were hypointense on T1-weighted images, and the cysts of 6 lesions were hyperintense on T1- and T2-weighted images without "shading." The nuclear grade was higher (P = 0.0028) and the clinical stage more advanced (P = 0.0018) in group B compared to group A. CONCLUSION: MRI of ovarian endometrioid adenocarcinomas revealed two types: a solid type and a cystic type. The lesions arising from endometriomas tended to be the cystic type on MRI and have a good prognosis. Preexisting endometrioma in this entity rarely showed "shading" on T2-weighted images.     

Magnetic resonance imaging in acute physeal injuries

Magnetic resonance imaging (MRI) permits noninvasive evaluation of the cartilage of the growth plate and epiphysis. This paper reports three cases where MRI was used to supplement conventional radiography in the assessment of acute physeal injuries. In the first patient, MRI was used for postoperative assessment of a radial neck fracture, avoiding further surgical exploration. In the second case, MRI was compared with ultrasonography in the diagnosis of proximal humeral epiphyseal separation in a neonate. In the third case, MRI and computed tomography were compared in evaluation of a Salter-Harris type 4 distal femur fracture. In all cases MRI was diagnostic. MRI is the investigation of choice in acute complex physeal injuries, and is particularly appropriate for use prior to the appearance of the secondary ossification center.     

Magnetic resonance imaging of intraosseous lipomas: a radiologic-pathologic correlation

Four patients with intraosseous lipomas were studied with magnetic resonance imaging. The imaging features and histology of each tumor were compared. Magnetic resonance imaging was very helpful in establishing a pathologic diagnosis. If a severe degree of involution was present, then the magnetic resonance findings could be ambiguous, making diagnosis more difficult.     

Magnetic resonance imaging features of asymptomatic bipartite patella

Objective

The purpose of our study was to describe the magnetic resonance imaging (MRI) features of bipartite patella in asymptomatic patients.

Materials and methods

The study was prospective in type and performed following institutional ethical committees approval. In total, 25 subjects were recruited into the study and informed consent obtained in each case. The local radiology database was utilised in conjunction with a clinical questionnaire to identify patients who had asymptomatic bipartite patella. Any patient with a history of trauma or symptomatic disease was excluded from the study. MRI imaging was performed in each case on a 1.5 T system using a dedicated knee coil and a standardised knee protocol. The images obtained were then analysed by two musculoskeletal radiologists in consensus.

Results

Of the 25 subjects, there were 8 females and 17 males. The mean age was 34.6 years. All but one of the bipartite fragments were located on the superolateral aspect of the patella. In 23 cases, one fragment was identified. The average transverse diameter of the fragment was 12.8 mm. The average distance between the fragment and the adjacent patella in the axial plane was 1.46 mm. In addition, the cartilage overlying the patella and accessory fragment was intact in all cases. The average thickness of the patella cartilage at its border to the fragment was 2.4 mm with an average ratio of the cartilage thickness of the fragment as compared with the cartilage thickness of the patella of 0.72. There was no evidence of high signal or bone marrow oedema on fluid sensitive sequences within either the patella or the fragment in any of the patients. Fluid was identified in the cleft between the patella and the fragment in the majority of cases.

Conclusions

Asymptomatic bipartite patella is characterised by intact but thinned cartilage along the border between the patella and the fragment, fluid between the cleft and a lack of any bone marrow oedema or high signal within the patella or its fragment.     

椎管内神经源性肿瘤的磁共振成像表现

目的分析椎管内神经源性肿瘤的磁共振成像（MRI）表现,探讨其影像特征及鉴别诊断。方法回顾性分析13例经手术病理证实的椎管内神经源性肿瘤（神经鞘瘤9例,神经纤维瘤4例）的MRI表现。结果肿瘤呈圆形或类圆形3例,椭圆形6例,不规则哑铃形4例。肿瘤呈等T1信号5例,长T1信号8例;等T2信号3例,长T2信号10例。病灶内可见片状或斑片状坏死3例。增强扫描4例明显不均匀强化,9例均匀强化。结论MRI检查对椎管内神经源性肿瘤具有较好的诊断价值,根据神经源性肿瘤的特征性表现可以很好地对椎管内肿瘤进行诊断和鉴别诊断。     

Comparison of double inversion recovery magnetic resonance imaging (DIR-MRI) and dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) in detection of prostate cancer: A pilot study

IntroductionDCE-MRI is established for detecting prostate cancer (PCa). However, it requires a gadolinium contrast agent, with potential risks for patients. The application of DIR-MRI is simple and may allow cancer detection without the use of an intravenous contrast agent by differentially nullifying signal from normal and abnormal prostate tissue, creating contrast between the cancer and background normal prostate. In this pilot study we gathered data from DIR-MRI and DCE-MRI of the prostate for an equivalence trial. We also looked at how the DIR-MRI appearance varies with the aggressiveness of PCa.MethodDIR-MRI and DCE-MRI were acquired. The images were assessed by an experienced Consultant Radiologist and a novice reporter (Radiographer). The potential PCa lesions were quantified using a lesion to normal ratio (LNR). Radiological pathological correlation was made to identify the MRI lesions that represented significant PCa. A Wilcoxon sign rank was used to compare DCE-LNR and DIR-LNR for PCa containing lesions. Pearson's correlation was used to look at the relationship between DIR-LNR and PCa grade group (aggressiveness).ResultsDCE-LNR and DIR-LNR were found to be significantly different (Z = −5.910, p < 0.001). However, a significant correlation was found between PCa grade group and DIR-LNR.ConclusionDIR and DCE sequences are not equivalent and significant cancer is more conspicuous on the DCE sequence. However, DIR-LNR does correlate with PCa aggressiveness.Implications for practiceWith the correlation of PCa grade group with DIR-LNR this may be a useful sequence in evaluation of the prostate; stratifying the risk of there being clinically significant PCa before biopsy is performed. Furthermore, given that DIR-LNR appears to predict PCa aggressiveness DIR might be used as part of a multiparametric MRI protocol designed to avoid biopsy.