Value of diffusion weighted magnetic resonance imaging in diagnosis and characterization of scrotal abnormalities

Background

MRI of scrotal lesions represents an important diagnostic tool in the evaluation of scrotal diseases. Diffusion weighted (DW) MR imaging is a promising technique which proved to improve tissue characterization.

Aim

To assess the diagnostic value and role of DWMR imaging in the detection and characterization of scrotal lesions.

Results

A prospective study included 50 scrotal lesions (35 intratesticular and 15 extra testicular) with 50 normal testes used as control. DW sequences were obtained using a b factor of 0, 500 and 900 s/mm²². The accuracy of conventional sequences, DW images alone and DW imaging combined with conventional images in differentiating benign from malignant scrotal lesions was calculated. There was significant difference between apparent diffusion coefficient (ADC) values of testicular malignancies, normal testis and benign intratesticular lesions, and the ADC values of benign extra testicular lesions from those of normal epididymis. The overall accuracy of conventional imaging, DW imaging alone and DWMR combined with conventional sequences in the characterization of intratesticular lesions was 90%, 87% and 100%, respectively.

Conclusion

Our findings suggest that DWMR imaging and ADC values may provide valuable information in the diagnosis and characterization of scrotal diseases.     

Diagnostic yield of combined magnetic resonance spectroscopy and diffusion weighted imaging in intracranial neoplasms

Purpose

Our intention was to evaluate the role of combined diffusion magnetic resonance imaging and spectroscopy in diagnosis and grading of brain tumors.

Materials and methods

Ninety-three included cases underwent magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) of the brain lesion, stereotactic or open biopsies and histopathological examination. MRI protocol included DWI and calculated ADC values. Multivoxel MRS spectroscopic technique (MVS) was used and all MRS metabolic parameters were obtained.

Results

High grade tumors had significantly lower ADC values than low grade tumors (P < 0.001). ADC values were the lowest in lymphoma (0.54 × 10⁻³ mm²/s) and the highest in craniopharyngioma (1.9 × 10⁻³ mm²/s). MRS revealed a statistically significant difference in CHO/NAA and CHO/Cr ratios between low and high grade tumors with P < 0.01 and P < 0.001, respectively. The mI/Cr ratio and presence of lactate, lipid and taurine also aided in differentiation and grading of brain tumors. The overall MRI/MRS sensitivity and specificity were 91%, 90.5%, respectively.

Conclusion

MRS has a robust diagnostic accuracy in cases of well defined high or low grade brain neoplasms. ADC value had the ability to confirm and differentiate low from high grade tumors in many situations where there were diagnostic confusions with MRS due to borderline values.     

Comparison of acquired diffusion weighted imaging and computed diffusion weighted imaging for detection of hepatic metastases

Objective

To compare the accuracy of acquired diffusion weighted imaging (DWI) (b = 1000 s/mm²) with that of computed DWI (b = 1000 s/mm²) for the detection of hepatic metastases.

Methods

Two hundred and sixty patients underwent abdominal magnetic resonance imaging (MRI) at 3.0 T for the evaluation of hepatic metastasis, including T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), heavily T2WI, DWI with b-values of 0, 500, 1000 s/mm², and three-dimensional dynamic contrast-enhanced MRI with gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA), and 190 patients were included in the final study. Computed DWI (=1000 s/mm²) was synthesized from lower b-values (b = 0 and 500 s/mm²). Two groups were assigned and compared: group A (acquired DWI) and group B (computed DWI). Diagnostic performance using each imaging set was evaluated by receiver operating characteristic (ROC) curve analysis.

Results

A total of 76 hepatic metastases were confirmed. The area under the ROC curve (Az) of group A was larger than that of group B (Observer 1; 0.919–0.915, Observer 2; 0.926–0.901), but there were no significant differences (observer 1, P = 0.500; observer 2, P = 0.190). There were 5 metastases visualized in group A, but these were difficult to detect in group B. However, there were 2 metastases that were better visualized in group B than in group A.

Conclusion

There were no significant differences between acquired DWI and computed DWI in the detection of hepatic metastasis.     

磁共振弥散加权成像对宫颈癌复发的诊断价值

目的探讨磁共振弥散加权成像对宫颈癌复发的诊断价值。方法收集宫颈癌术后在我院复查MRI检查患者121例,其中行放疗37例,以手术或穿刺病理证实复发32例,先分为复发组与未复发组,再按术后是否行放射治疗分为单纯术后组及手术加放疗组,复发组分为单纯术后复发组及手术后加放疗后复发组,分别测量术后、放疗后宫颈残端与复发肿瘤的ADC值,进行对比分析;采用DWI诊断宫颈癌复发与病理进行对照比较,以敏感性、特异性及准确率三项指标分析DWI对其复发的诊断价值。结果术后、术后放疗后与复发癌灶ADC值两两对比,差异有显著性意义,术后复发与术后放疗后复发无统计学意义;DWI成像对宫颈癌复发的敏感性、特异性及准确率分别为：100％、95．51％、96．69％。结论弥散加权成像可以作为评估宫颈癌复发的准确检查方法。     

不同期相脑梗死在扩散加权成像中的信号特征及临床应用

目的:探讨在不同期相脑梗死中DWI(核磁共振扩散加权成像)及ADC图(表观弥散系数图像)的信号特点及其成像技术对脑梗死的应用价值。方法:对54例脑梗死患者,应用SE-T1WI、FSE-T2WI、T2-FLAIR、DWI序列进行横断位扫描,及ADC图像重建,并按发病时间分为超急性期、急性期、亚急性期和慢性期,观察并测量DWI图像及ADC图在不同期相脑梗死中的信号强度和ADC值的大小。结果:对于超急性期和急性期的脑梗死病灶,其DWI信号明显高于正常脑组织(P<0.05),其ADC值则低于正常脑组织(P<0.05),二图对其均有很高的显示度;对于亚急性期病灶,其DWI信号高于正常脑组织(P<0.05),其ADC值与正常脑组织信号差别不大(P>0.05),DWI可以显示病灶;对于慢性期病灶,DWI信号等或稍低于正常脑组织,对病灶显示意义不大(P>0.05),而ADC值高于正常脑组织(P<0.05),可以显示病灶区域。结论:DWI和ADC图对超急性期、急性期脑梗死都有很大的诊断意义,DWI对亚急性期病灶有一定显示度,ADC图对慢性期梗死灶也有一定诊断意义。     

Efficiency of combined diffusion weighted imaging and conventional MRI in detection of clinically nonpalpable undescended testes

Purpose

The goal of the study was to highlight the added value of combined DWI and conventional MRI in detecting clinically nonpalpable undescended testes.

磁共振扩散加权成像在宫颈癌诊断中的应用

目的评价MR弥散加权成像(DWI)在宫颈癌诊断中应用的价值。方法对30例非宫颈肿瘤女性的子宫颈和50例宫颈癌患者的子宫颈进行常规MRI扫描和横断面DWI(b=600s/mm2),比较正常宫颈和宫颈癌病灶的表观弥散系数(apparent diffusion coefficient,ADC)值。结果正常子宫颈DWI表现为粘液,内、中、外带四层结构,其平均ADC值〔(1.71±0.14)×10-3 mm2/s)〕显著高于宫颈癌的ADC值〔(0.97±0.13)×10-3 mm2/s)〕(P<0.01)。结论 ADC值可有效地定量区分宫颈癌与正常宫颈,DWI更容易显示宫颈癌及其周围侵犯和盆腔淋巴结转移。     

Value of diffusion weighted magnetic resonance imaging in grading of urinary bladder carcinoma

Aim of the study: to evaluate the role of diffusion weighted magnetic resonance imaging in urinary bladder cancer grading in comparison to histopathological grading.

Solitary thyroid nodule: Diagnostic yield of combined diffusion weighted imaging and magnetic resonance spectroscopy

Aim

The scope of this study is to evaluate the combined application of MR-DWI and MRS in differentiating between benign and malignant thyroid nodules.

磁共振扩散加权成像在胰腺癌诊断中的价值

目的探讨磁共振扩散加权成像在胰腺癌诊断中的价值。方法选择2012年1月～2013年1月间临床可疑胰腺癌患者75例,对这些患者进行磁共振扩散加权成像检查,将检查结果与病理结果比较,明确两者之间的相关性,同时确定磁共振扩散加权成像在胰腺癌诊断中的敏感性、特异性。结果75例可疑胰腺癌患者经DWI检查,诊断为胰腺癌38例,与病理结果比较,两者存在相关性（r=23．12,P=-0．00〈0．05）,且相关系数为0．56。同时与病理结果比较DWI诊断胰腺癌的敏感性为73．33％,特异性为83．33％,阳性预测值和阴性预测值分别为86．84％和67．57％。结论磁共振扩散加权成像作为无创检查手段能够准确地对胰腺占位做出定性诊断,在临床应用价值较大。     

磁共振扩散加权成像预测与评价宫颈癌放化疗疗效的研究

目的 探讨磁共振扩散加权成像(DWI)在预测与评价宫颈癌放化疗疗效中的应用价值.方法 收集282例经病理检查证实为宫颈癌的患者,分别在治疗前、治疗结束后行DWI检查,测量肿瘤最大径和表现扩散系数(ADC)值.治疗结束后,依据实体肿瘤疗效评价标准(RECIST)将患者分为缓解组、无效组.根据治疗结束后2年的随访复查情况将患者分为复发组、无复发组.比较两组间的治疗前和治疗结束后ADC值,并分析疗效及复发情况与治疗前ADC值、治疗结束后的ADC升高值之间的相关性. 结果 缓解组223例,无效组59例.复发组70例,无复发组212例.缓解组治疗前ADC值明显低于无效组(t=3.274,P<0.05),无复发组治疗前ADC值明显低于复发组(t=1.031,P<0.05).治疗前ADC值低的患者复发率明显低于治疗前ADC值高的患者(χ²=5.175,P<0.05).治疗结束后的疗效及治疗结束后2年的复发情况与治疗前ADC值均呈负相关(r=-0.571、-0.675,P<0.05),与治疗结束后的ADC升高值均呈正相关(r=0.641、0.547,P<0.05).缓解组、无复发组治疗结束后ADC值升高明显(t=2.031、4.011,P<0.05),无效组、复发组ADC值升高不明显.结论 治疗前的ADC值有助于预测宫颈癌放化疗疗效,治疗结束后的ADC变化值有助于评价宫颈癌放化疗疗效.     

Role of diffusion weighted imaging and proton magnetic resonance spectroscopy in ring enhancing brain lesions

Aim of the work

To assess and compare the usefulness and efficacy of both diffusion weighted imaging (DWI) and proton magnetic resonance spectroscopy (¹HMRS) in brain lesions with ring enhancement in post contrast T1WI and to determine which method is more effective.

Subjects and methods

Thirty patients with ring-enhanced brain lesions were classified into 2 groups, abscess group (11 patients) and tumor group (19 patients), were examined using diffusion-weighted imaging (DWI) and H-proton magnetic resonance spectroscopy (¹HMRS).

Results

Restricted diffusion and low ADC value were seen in 9 (81%) patients of brain abscesses, however, free diffusion and high ADC value were found in 18 (94%) patients with necrotic brain tumor. The abscess group showed aminoacids, acetate and lactate in 9 patients and extra peak of succinate was found in 1 patient; however in the tumor group lactate alone was found in 12 patients, lactate and choline were seen in 5 patients, none of the patients showed amino acids, succinate or acetate.

Conclusion

Both DWI and ¹HMRS are useful and efficient imaging techniques in ring enhancing brain lesions and differentiate between pyogenic brain abscesses and necrotic tumors, but DWI is accurate, has less imaging time than ¹HMRS, also is available in many imaging centers.     

Identification of inguinal lymph node metastases from vulval carcinoma by magnetic resonance imaging: an initial report

AIM: Magnetic Resonance Imaging (MRI) has the potential to assess inguinal lymph nodes more accurately than palpation and less invasively than surgical exploration. The objective of this study was to measure the accuracy of MRI in identifying inguinal metastases by demonstrating abnormal lymph node morphology. MATERIALS AND METHODS: 10 women with vulval malignancy underwent T1- and fat-suppressed T2-weighted surface coil MRI of both groins before surgery. Each groin was prospectively categorised as normal or as having metastatic lymphadenopathy using criteria established in normal volunteers. Histopathological findings in patients undergoing groin dissection for invasive vulval carcinoma were used as validation. RESULTS: MRI had a positive predictive value of 89%, negative predictive value of 91%, sensitivity of 89%, specificity of 91% and accuracy of 90%. The most useful observations on MRI to identify metastatic lymphadenopathy were those of lymph node contour irregularity, cystic change in a lymph node, short axis diameter exceeding 10mm and abnormal long: short axis diameter ratio. CONCLUSION: High resolution MRI of the inguinal regions has potential to screen for lymph node metastases in patients with vulval cancer, with the aim of reducing the number of women who have to undergo groin dissection.     

食管癌MR扩散加权成像研究进展

MR扩散加权成像是活体状态下评价组织水分子与微循环的扩散运动的一种无创性手段,为肿瘤诊断、分期及治疗效果评估提供重要信息。扩散加权成像的表观扩散系数(ADC)可作为一种有价值的放射学定量指标,应用于食管癌的早期诊断,评价肿瘤血管生成及分期、分级,预测放化疗疗效及评估治疗效果。就扩散加权成像在食管癌中的应用予以综述。     

Comparison of breast cancer detection by diffusion-weighted magnetic resonance imaging and mammography

PURPOSE: Breast cancer-detecting ability of diffusion-weighted magnetic resonance imaging (DW-MRI) was investigated by comparing the breast cancer detection rates of DW-MRI and mammography (MMG). MATERIALS AND METHODS: The subjects were 48 women who had breast cancer (53 cancer lesions) who underwent DW-MRI before surgery. Altogether, 41 lesions were invasive ductal carcinoma (IDC), 7 were noninvasive ductal carcinoma (NIDC) and 5 were "others." RESULTS: The breast cancer detection rates by MMG and DW-MRI were 84.9% and 94.3% (P < 0.001), respectively. In each classification of histology and size, the detection rate by DW-MRI was higher than that by MMG. In relation to the mammary gland density, the detection rates of fatty, scattered, heterogeneously dense, and extremely dense mammary glands were 100%, 100%, 92.0%, and 83.3%, respectively. The mean apparent diffusion coefficient values of the histologic types were 1.07 +/- 0.17 x 10(-3), 1.50 +/- 0.24 x 10(-3), 1.12 +/- 0.25 x 10(-3), and 2.01 +/- 0.29 x 10(-3) mm(2)/s for IDC, NIDC, others, and normal breast, respectively, showing that the values of IDC and NIDC were significantly different from that of the normal breast (P < 0.001 each). A significant difference was also noted between IDC and NIDC (P < 0.001). CONCLUSION: DW-MRI may be useful for detecting breast cancer in a wide age group of women, including young women with dense mammary glands.     

Diagnostic value of diffusion weighted magnetic resonance image in early ankylosing spondylitis

Background

Diffusion-weighted MRI (DW-MRI) shows the early changes in microscopical movement of water molecules, hence diagnosis of early sacroiliitis which is one of the diagnostic criteria of seronegative spondyloarthropathies.

Objective

To determine the value of DW-MRI in detection of signal characteristics of the sacroiliac joints in patients with early ankylosing spondylitis (AS).

Patients and methods

Fifteen patients with clinically suspected AS, 20 patients with mechanical low back pain and 20 healthy controls underwent conventional MRI and DWI. Apparent diffusion coefficient (ADC) was measured. In addition ten clinically confirmed AS patients underwent whole body-DWI.

Results

Mean ADC values of both sacroiliac joints in AS patients were (0.523 ± 0.15) × 10⁻³ mm²/s in the ilium and (0.502 ± 0.15) × 10⁻³ mm²/s in the sacrum. There was no significant difference between mechanical LBP and healthy controls. But there was a significant difference between AS and LBP patients. Mean ADC value of focal lesions of clinically confirmed AS was 0.965 ± 0.25 × 10⁻³ mm²/s in the sacrum and 0.932 ± 0.31 × 10⁻³ mm²/s in the ilium.

Conclusion

Subchondral bone marrow ADC values of sacroiliac joints allow differentiation between inflammatory and mechanical LBP. Furthermore, it may be helpful in evaluating the efficacy of the treatment and determine disease prognosis.     

Lymph node metastasis in head and neck squamous carcinoma: Efficacy of intravoxel incoherent motion magnetic resonance imaging for the differential diagnosis

PurposeTo evaluate the value of pure molecular diffusion(D), perfusion-related diffusion (D*), perfusion fraction (f) and apparent diffusion coefficient (ADC) based on intravoxel incoherent motion (IVIM) theory for differential diagnosis of metastatic lymph nodes (LNs) in head and neck squamous cell carcinoma(HNSCC).Materials and methods29 patients with HNSCC and 20 patients with lymph node hyperplasia (LNH) were enrolled in this retrospective study, underwent magnetic resonance (MR) examination. IVIM Diffusion-weighted imaging (IVIM-DWI) was performed with 13 b values. D, D*, f and ADC values were compared between two groups. The diagnostic value of ADC, D, D* and D·D* value were evaluated by Receiver operating characteristic (ROC) curve. Two radiologists measured D, D*, f and ADC values independently.Results33 malignant LNs in HNSCC group and 22 benign LNs in LNH group (minimum diameter, ≥5 mm) were successfully examined, ADC(P < 0.05), D (P < 0.01) and f (P < 0.01) were significantly lower in malignant LNs than that in benign LNs, whereas D* was significantly higher (P < 0.01). The area under the ROC curve (AUC) for D·D* was 0.983 and was larger than that for D* (0.952), D (0.78) and ADC (0.67).ConclusionOur results indicate that IVIM DWI is feasible in the diagnosis of LN metastasis. D was significantly decreased in malignant LNs reflected increased nuclear-to-cytoplasmic ratio tissue, and D* was significantly increased reflected increased blood vessel generation and parenchymal perfusion in malignant LNs.     

PI-RADS version 2: Preoperative role in the detection of normal-sized pelvic lymph node metastasis in prostate cancer

ObjectivesTo analyze whether Prostate Imaging Reporting and Data System (PI-RADSv2) scores are associated with a risk of normal-sized pelvic lymph node metastasis (PLNM) in prostate cancer (PCa).Materials and methodsA consecutive series of 221 patients who underwent magnetic resonance imaging and radical prostatectomy with pelvic lymph node dissection (PLND) for PCa were retrospectively analyzed under the approval of institutional review board in our institution. No patients had enlarged (≥0.8 cm in short-axis diameter) lymph nodes. Clinical parameters [prostate-specific antigen (PSA), greatest percentage of biopsy core, and percentage of positive cores], and PI-RADSv2 score from two independent readers were analyzed with multivariate logistic regression and receiver operating-characteristic curve for PLNM. Diagnostic performance of PI-RADSv2 and Briganti nomogram was compared. Weighted kappa was investigated regarding PI-RADSv2 scoring.ResultsNormal-sized PLNM was found in 9.5% (21/221) of patients. In multivariate analysis, PI-RADSv2 (reader 1, p = 0.009; reader 2, p = 0.026) and PSA (reader 1, p = 0.008; reader 2, p = 0.037) were predictive of normal-sized PLNM. Threshold of PI-RADSv2 was a score of 5, where PI-RADSv2 was associated with high sensitivity (reader 1, 95.2% [20/21]; reader 2, 90.5% [19/21]) and negative predictive value (reader 1, 99.2% [124/125]; reader 2, 98.6% [136/138]). However, diagnostic performance of PI-RADSv2 (AUC = 0.786–0.788) was significantly lower than that of Briganti nomogram (AUC = 0.890) for normal-sized PLNM (p < 0.05). The inter-reader agreement was excellent for PI-RADSv2 of 5 or not (weighted kappa = 0.804).ConclusionPI-RADSv2 scores may be associated with the risk of normal-sized PLNM in PCa.     

磁共振扩散成像及磁敏感加权成像在脊髓损伤中的应用

目前,脊髓MR成像常规检查是诊断脊髓损伤的最佳手段,能清楚地显示受损伤脊髓形态及信号改变,以此明确疾病,但是当MRI常规检查出现信号改变时往往提示脊髓损伤严重,并非病变的早期,使得病人错过最佳治疗时期。而MR扩散加权成像(DWI)和磁敏感加权成像(SWI)对脊髓损伤的早期诊断、治疗和预后均具有重要价值。对DWI及SWI在急慢性脊髓损伤中的应用情况及研究进展进行综述。