Role of diffusion weighted MRI in differentiating typical from atypical meningiomas at 1.5 and 3T MRI

Purpose

Atypical and malignant meningiomas are considered to have a higher rate of recurrence and show aggressive behavior compared to benign variety. The purpose of our study was to study the role of diffusion weighted imaging and determination of apparent diffusion coefficient (ADC) values and ADC ratios to differentiate typical meningiomas from atypical/malignant variety at 1.5 and 3T MRI.

Materials and methods

A total of 94 adult patients (48 patients at 3T and 46 patients at 1.5T) with pathologically proven meningiomas were retrospectively evaluated on conventional and diffusion weighted MRI. The signal intensity of the lesions on DW imaging was evaluated. ADC values and ADC ratios were calculated from lesion and contralateral normal white matter.

Results

94 lesions comprising of 66 benign and 28 atypical meningiomas were evaluated. The mean ADC values at 3T MRI were 0.82 ± 0.12 × 10⁻³ in benign (typical) meningiomas and 0.68 ± 0.10 × 10⁻³ in atypical meningiomas. At 1.5T, the mean ADC values of benign meningiomas were 0.83 ± 0.11 × 10⁻³ and 0.70 ± 0.09 × 10⁻³ in atypical meningiomas. The mean ADC ratios were 1.08 ± 0.17 and 0.85 ± 0.15 for benign and atypical meningiomas respectively. There was a statistically significant difference between the mean ADC ratios and the mean ADC values of typical and atypical meningiomas (P < 0.001) at both 1.5T and 3T MRI.

Conclusion

DWI with calculation of apparent diffusion coefficient (ADC) values and ADC ratios has a potential role in differentiating benign from atypical meningiomas at both 1.5 and 3T MRI. The differences in mean ADC values between benign and atypical meningiomas were similar at both 1.5 and 3T MRI.     

Correlating apparent diffusion coefficients with histopathologic findings on meningiomas

Purpose

To determine whether the apparent diffusion coefficient (ADC) correlates with histopathologic findings and whether ADC values can be used to differentiate benign from atypical/malignant meningiomas.

Materials and methods

MR images were reviewed retrospectively in 138 patients with meningiomas treated between September 1997 and July 2003. The ADC values were measured in the lesions and peritumoral edema, and the normalized ADC (NADC) ratios were calculated using the formula NADC = ADC of the tumor/ADC of the normal white matter. The ADC findings were compared with the histopathologic findings after resection using the World Health Organization criteria (2007).

Results

Meningiomas were histologically graded as malignant (9%), atypical (14%) and benign (77%). Of the 138 meningiomas, 32 (23%) were atypical (n = 19) or malignant (n = 13), whereas 106 (77%) were typical. The mean ADC values were statistically different between typical and atypical/malignant meningiomas (0.97 ± 0.21 × 10⁻³ mm²/s vs 0.85 ± 0.17 × 10⁻³ mm²/s). The mean NADC ratios were also significantly lower in the atypical/malignant group (1.09 ± 0.23) than in the benign group (1.24 ± 0.25; P = 0.002 < 0.05). The mean ADC values and NADC ratios did not differ significantly among fibrous, meningothelial, transitional and atypical tumors (P > 0.05). The mean ADC values and NADC ratios were higher in the angiomatous and secretory subgroups than in the fibrous, meningothelial, transitional, atypical and malignant subgroups (P < 0.05). The ADC values and NADC ratios were the lowest in the malignant subgroup, and the difference between atypical and malignant meningiomas was statistically significant (P < 0.05).

Conclusions

Meningioma subgroups displayed different ADC values from each other. Thus, ADC values may provide a useful supplement to the information obtained from conventional contrast-enhanced MR imaging, enhancing the ability of medical professionals to differentiate among the subgroups of meningiomas.     

Diffusion weighted MRI and transient elastography assessment of liver fibrosis in hepatitis C patients: Validity of non invasive imaging techniques

Objective

Treatment for hepatitis C infection and monitoring of progression were based on degree of fibrosis, which were traditionally diagnosed by liver biopsy but it has many limitations. We aim to evaluate noninvasive imaging methods, so-called diffusion-weighted MRI (DW MRI) and transient elastography [(TE), fibroscan] in diagnosing liver fibrosis in hepatitis C (HCV) patients.

Patients

The Study included 102 hepatitis C patients (62 male) with mean age of 38 ± 5. For all patients liver biopsy was done followed by DW MRI and TE. METAVIR classification system was used for staging liver fibrosis. Data obtained were collected and results of DW MRI and TE were compared with those of histopathology. The diagnostic performance of ADC and TE was determined using areas under receiver operating characteristic (AUROC) curves for significant fibrosis ?F3.

Results

Measuring ADC at different b-values had a significant negative correlation with stage of fibrosis P = 0.001, the best negative correlation at b-value of 700 mm²/s. TE had a significant positive correlation with stage of fibrosis P = 0.005. Both examination showed a significant difference between fibrosis stage <F3 and stages ?F3 with P < 0.00 for ADC measure at each b-value and TE respectively.

Conclusion

This study suggests that DW MRI and TE had favorable comparable results with liver biopsy for the diagnosis of significant liver fibrosis.     

MR spectroscopy and diffusion MR imaging in characterization of common sellar and supra-sellar neoplastic lesions

Background

MR spectroscopy and diffusion-weighted imaging are useful non invasive imaging modalities used for characterization of different sellar and suprasellar lesions.

Patient and methods

We studied 30 cases of suprasellar SOLs (as proved by conventional MRI), MRS and DWI. Our findings were correlated with histopathological analysis after surgical resection.

Results

Three false positive cases in which cMRI give diagnosis mismatched with that obtained after adding the MRS findings and ADC values. MR spectrum type IIC is found in macroadenoma, craniopharyngioma, meningioma and germinoma with characteristic broad lipid peak in the second and forth types and elevated alanine peak in meningioma. Glioma had MRS appearance of type IIB. Simple differentiation between tumor types were achieved by the mean ADC values which were statistically significant (p < 0.001) when correlated to the histological diagnosis. When the ADC value of 0.6 × 10⁻³ mm²/s this strongly points to macroadenoma, ADC value of 1.05 × 10⁻³ mm²/s in meningiomas, ADC value 1.88 8 × 10⁻³ mm²/s strongly points to craniopharyngioma, while gliomas and germinoma had ADC values 1.6 × 10⁻³ mm²/s and 1.0 × 10⁻³ mm²/s respectively.

Conclusion

MR spectroscopy and DWMRI are considered important diagnostic tools complementary to cMRI in pre-surgical evaluation and discrimination between different sellar and suprasellar lesions.     

Diagnostic accuracy of apparent diffusion coefficient value in differentiating metastatic form benign axillary lymph nodes in cancer breast

Purpose

To detect axillary lymph node metastasis based on diffusion Weighted MR and apparent diffusion coefficient (ADC) in the known breast cancer cases.

Patient and methods

Forty-four patients were included in this study for preoperative MRI staging of the breast cancer and axillary lymph node assessment. The lymph node criteria (long/short-axis ratio, T2WI, DWI and ADC value) were included in the analysis. Images were obtained with diffusion sensitizing gradients of 0 and 750 mm²/s. The ADC was calculated.

Results

Thirty-two patients had metastatic axillary lymph nodes and 12 cases had no malignant LN involvement. There was no significant difference between both in S/L ratio, T2WISI (p < 0.140 & p = 0.079, respectively), while statistically significant difference between benign and malignant lymph nodes in both DWI and ADC mean values (p < 0.0001 & p < 0.007, respectively). The optimal ADC cut off value was ?.8 × 10⁻³ mm²/s for differentiation between benign and malignant lymph nodes with accuracy 96.7%, sensitivity 100%, specificity 87%, PPV 95.4% and NPV 100%.

Conclusion

Compared with lymph node size or routine magnetic resonance sequences, DWI and ADC are promising techniques for differentiating metastatic and non metastatic axillary lymph nodes in known breast cancer patients.     

Diffusion-weighted imaging properties of uterine fibroids pre- and post-uterine fibroid embolisation

Objective

To determine the change in apparent diffusion coefficient (ADC) of uterine fibroids following uterine fibroid embolisation (UFE), and if the ADC change correlates with either volume loss or degree of contrast enhancement post-UFE.

Materials and methods

This study was approved by our institutional review board with waiver of consent. The pelvic MRI examinations, including diffusion-weighted MRI (DWI) using 4 b-values, of 50 consecutive patients prior to and 6 months post-UFE were analyzed. The volume, ADC and amount of enhancement were calculated for each fibroid both pre- and post-UFE. The percent residual enhancement for each fibroid was categorized as either: no (0–1%) residual enhancement or residual (>1%) enhancement. Statistical analysis compared ADC, enhancement and volume for each fibroid pre- and post-UFE using paired t-tests and Pearson correlation coefficients.

Results

The mean ADC of all (n = 88) fibroids pre-UFE was 1.30 ± 0.20 × 10⁻³ mm²/s, and increased to 1.68 ± 0.24 × 10⁻³ mm²/s post-UFE (p < 0.0001). Lower pre-UFE ADC correlated with greater ADC change post-UFE (r = −0.50; p < 0.0001). There was no correlation between ADC change and volume change post-UFE (r = 0.07; p = 0.59). However, fibroids with no residual enhancement post-UFE had larger ADC change than those with residual enhancement (p = 0.003).

Conclusion

The ADC of fibroids rises post-UFE. ADC change post-UFE is associated with the degree of loss of enhancement and may therefore be valuable in predicting response to treatment in pre-procedural counseling.     

Is diffusion-weighted imaging useful in grading and differentiating histopathological subtypes of meningiomas?

Purpose

Meningiomas are mostly benign, however atypical or malignant subtypes with more aggressive clinical course and higher recurrence rates can also be seen. The purpose of this study was to determine whether histopathological subtypes of meningiomas could be assessed preoperatively using apparent diffusion coefficient (ADC) values.

Materials and methods

Conventional magnetic resonance (MR) and diffusion-weighted (DW) imaging of 177 adult patients with pathologically proven meningiomas were retrospectively evaluated. Tumor size and the degree of associated edema were noted. The signal intensity of the lesions on DW imaging was evaluated and graded. Mean ADC values were obtained as the mean of measurements from three regions of interests within the mass. ADC ratios of meningioma/contralateral normal appearing subcortical parietal white matter were also calculated.

Results

The histopathological analysis revealed 135 benign, 37 atypical and 5 malignant lesions. With classification according to the subtype, the mean ADC values and ratios of benign meningiomas were as 0.99 ± 0.12 × 10⁻³ mm²/s and 1.22 ± 0.07, respectively. ADC values for atypical and malignant groups were both 0.84 ± 0.1 × 10⁻³ mm²/s. The ADC ratios were 1.05 ± 0.1 and 0.96 ± 0.2 for atypical and malignant subtypes, respectively. There was no statistically significant difference between the mean ADC ratios of the three subtypes (ANOVA test; P ≥ 0.05). Gender, age of the patients and tumor size showed no statistically significant difference between the different histological groups.

Conclusion

DW MR imaging was not found to have any additional value in determining histological behaviour nor in differentiating histopathological subtypes of meningiomas.     

Can pretreatment ADC values predict recurrence of bladder cancer after transurethral resection?

Objective

The aim of this retrospective study was to investigate the association between the pretreatment apparent diffusion coefficient (ADC) value and recurrence of bladder cancer after transurethral resection.

Methods

Patients with superficial bladder cancer were identified. Mean ADC values of the tumors were compared between patients with and without recurrence following trans-urethral resection. A receiver–operator characteristic curve was used for determining the optimal cutoff ADC value. Univariate and multivariate analyses were used to determine the effect of ADC values and other factors.

Results

With a mean follow-up period of 25 months, bladder cancer recurred in 14 of 44 patients (32%). The mean ADC value of tumors in patients with recurrence was lower than in those without recurrence (1.08 mm²/s vs. 1.28 × 10⁻³ mm²/s; p = 0.003). The optimal cutoff ADC value for predicting recurrence was determined to be 1.12 × 10⁻³ mm²/s. A modest and significant negative correlation was observed between the ADC values and tumor size (r = −0.436, p = 0.008). After adjustment for size and risk groups, an ADC value equal to or less than the optimal cutoff remained a significant predictor of recurrence (odds ratio 6.3, 95% CI 1.23–32.2, p = 0.027).

Conclusion

Pretreatment ADC values may be an independent predictor of bladder cancer recurrence.     

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.     

Diffusion tensor imaging of the median nerve at 3.0 T using different MR scanners: Agreement of FA and ADC measurements

Objective

To assess the agreement of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of the median nerve on 3.0 T MR scanners from different vendors.

Materials and methods

IRB approved study including 16 healthy volunteers (9 women; mean age 30.6 ± 5.3 years). Diffusion tensor imaging (DTI) of the dominant wrist was performed on three 3.0 T MR scanners (GE, Siemens, Philips) using similar imaging protocols and vendor-proprietary hard- and software. Intra-, inter-reader and inter-vendor agreements were assessed.

Results

ICCs for intra-/inter-reader agreements ranged from 0.843–0.970/0.846–0.956 for FA, and 0.840–0.940/0.726–0.929 for ADC, respectively.ANOVA analysis identified significant differences for FA/ADC measurements among vendors (p < 0.001/p < 0.01, respectively). Overall mean values for FA were 0.63 (SD ± 0.1) and 0.999 × 10⁻³ mm²/s (SD ± 0.134 × 10⁻³) for ADC. A significant negative measurement bias was found for FA values from the GE scanner (−0.05 and −0.07) and for ADC values from the Siemens scanner (−0.053 and −0.063 × 10⁻³ mm²/s) as compared to the remainder vendors

Conclusion

FA and ADC values of the median nerve obtained on different 3.0 T MR scanners differ significantly, but are in comparison to the standard deviation of absolute values small enough to not have an impact on larger group studies or when substantial diffusion changes can be expected. However, caution is warranted in an individual patient when interpreting diffusion values from different scanner acquisitions     

Serial diffusion-weighted MRI in patients with hepatocellular carcinoma: Prediction and assessment of response to transarterial chemoembolization. Preliminary experience

Objective

To assess the role of apparent diffusion coefficient (ADC) measured with diffusion-weighted imaging (DWI) in predicting and assessing response of hepatocellular carcinoma (HCC) to transarterial chemoembolization (TACE).

Methods

Thirty-six patients with cirrhosis and untreated HCC who underwent TACE and MRI within 3 months before and after TACE were assessed. MRI included DWI and contrast-enhanced T1-weighted imaging. Two observers measured ADC of HCCs and liver parenchyma on pre- and post-TACE MRIs and measured degree of tumor necrosis on subtracted post-contrast images on post-TACE MRI. Pre-, post-TACE tumor ADC, and changes in tumor ADC (ΔADC) were compared between lesions stratified by degree of tumor necrosis (measured on post-TACE MRI).

Results

Forty seven HCCs were evaluated (mean size 4.4 cm, range 1.0–14.1 cm). HCCs with poor and incomplete response to TACE (<50% necrosis on post-TACE MRI) had significantly lower pre-treatment ADC and lower post TACE ADC compared to HCCs with good/complete response (≥50% necrosis): ADC pre-TACE 1.35 ± 0.42 vs. 1.64 ± 0.39 × 10⁻³ mm²/s (p = 0.042); post-TACE ADC 1.34 ± 0.36 vs. 1.92 ± 0.47 (p = 0.0008). There was no difference in ΔADC values.

Conclusion

This preliminary data suggests that pre-TACE tumor ADC can be used to predict HCC response to TACE.     

Apparent diffusion coefficient values as an adjunct to dynamic contrast enhanced MRI for discriminating benign and malignant breast lesions presenting as mass and non-mass like enhancement

Purpose

The purpose of our study was to evaluate the diagnostic value of an imaging protocol that combines dynamic contrast-enhanced MRI (DCE-MRI) and apparent diffusion coefficient (ADC), measured by diffusion weighted MRI, in discriminating benign and malignant breast lesions presenting as mass and non mass like enhancement (NMLE).

Methods and materials

80 patients with 110 breast lesions identified with dynamic contrast MRI. Diffusion-weighted images were obtained at b values of 0 and 750 S/mm², differences in the apparent diffusion coefficients (ADCs) are included in the study and malignant lesions were compared by lesion type (mass or NMLE), and the analysis was performed to evaluate diagnostic performance based on ADC thresholds. All lesions have pathological results. The study has been done retrospectively 50 patients underwent surgical excision with preoperative localization, while the 30 cases underwent stereotactic biopsies either US or mammographically guided techniques specially if associated with micro calcifications.

Results

The mean ADC value of all benign lesions is 1.41 ± 0.36 × 10⁻³ mm²/s, which is higher than the mean ADC of all malignant lesions (1.05 ± 0.30 × 10⁻³ mm²/s, p < 0.05). In the MASS type, the mean ADC is higher in the benign group (1.34 ± 0.30 × 10⁻³ mm²/s) than in the malignant group (1.02 ± 0.29 × 10⁻³ mm²/s, p < 0.01). In the NMLE type, the mean ADC is also higher in the benign group (1.54 ± 0.45 × 10⁻³ mm²/s) than in the malignant group (1.11 ± 0.32 × 10⁻³ mm²/s, p < 0.01). Therefore, benign lesions have higher ADC values than malignant lesions, regardless of the lesion morphology.

Conclusion

Diffusion-weighted MRI shows adequate help in differentiation of benign and malignant masses and lesions with non-mass like enhancement found at breast MRI.     

Comparison of the diagnostic performances of diffusion parameters in diffusion weighted imaging and diffusion tensor imaging of breast lesions

Purpose

To evaluate the diagnostic efficiency of the diffusion parameters measured by conventional diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) for discrimination of malignant breast lesions from benign lesions and the normal breast.

Materials and methods

The study included 52 women with 55 breast lesions (30 malignant, 25 benign). DTI and DWI were performed complementary to dynamic contrast MRI at 3T. Apparent diffusion coefficient (ADC) of DWI, mean diffusivity (MD) and fractional anisotropy (FA) values of DTI were measured for lesions and contralateral breast parenchyma in each patient. We used b factors of 0, 50, 850, 1000 and 1500 s/mm² for DWI and b 0 and 1000 s/mm² for DTI. ADC, MD and FA values were compared between malignant and benign lesions, and the normal parenchyma by univariate and multivariate analyses.

Results

Diffusion parameters showed no difference according to menopausal status in the normal breast. ADC and MD values of the malignant lesions were significantly lower than benign lesions and normal parenchyma (p = 0.001). The FA showed no statistical significance. With the cut-off values of ≤1.23 × 10⁻³ mm²/s (b 0–1000 s/mm²) and ≤1.12 × 10⁻³ mm²/s (b 0–1500 s/mm²), ADC showed 92.85% and 96.15% sensitivity; 72.22% and 73.52% PPV, respectively. With a cut-off value of ≤1.27 × 10⁻³ mm²/s (b 1000 s/mm²), MD was 100% sensitive with a PPV of 65.90%. Comparing the diagnostic performance of the parameters in DTI with DWI, we obtained similar efficiency of ADC with b values of 0,1000 and 0,1500 s/mm² and MD with a b value of 0, 1000 s/mm² (AUC = 0.82 ± 0.07).

Conclusion

ADC of DWI and MD of DTI values provide significant discriminative factors for benign and malignant breast lesions. FA measurement was not discriminative. Supported with clinical and dynamic contrast MRI findings, DWI and DTI findings provide significant contribution to the final radiologic decision.     

Parallel-transmit-accelerated spatially-selective excitation mri for reduced-fov diffusion-weighted-imaging of the pancreas

Objectives

To find out whether the use of accelerated 2D-selective parallel-transmit excitation MRI for diffusion-weighted EPI (pTX-EPI) offers advantages over conventional single-shot EPI (c-EPI) with respect to different aspects of image quality in the MRI of the pancreas.

Materials and methods

The MRI examinations of 33 consecutive patients were evaluated in this prospective and IRB-approved study. PTX-EPI was performed with a reduced (zoomed) FOV of 230 × 118 mm². The 2D-RF pulse of pTX-EPI was accelerated, i.e. shortened by a factor of 1.7 (pTX-acceleration factor). C-EPI used a full-FOV of 380 × 285 mm². In a qualitative analysis, two experienced readers evaluated 3 different aspects of image quality on 3- to 5-point Likert scales. Additionally, apparent diffusion coefficients (ADCs) were determined in both c-EPI and pTX-EPI in normal-appearing pancreatic tissue using regions of interests (ROIs). Mean ADC values and standard deviations were compared between the two techniques.

Results

The reduced-FOV pTX-EPI was superior to c-EPI with respect to overall image quality (p < 0.0001) and identifiability of the pancreatic ducts (p < 0.01). Artifacts were significantly less severe in pTX-EPI (p < 0.01). The mean ADC values of c-EPI (1.29 ± 0.19 × 10⁻³ mm²/s) and pTX-EPI (1.27 ± 0.17 × 10⁻³ mm²/s) did not differ significantly between the two techniques (p = 0.44). The variation within the ROIs as measured by the standard deviation was significantly lower in pTX-EPI (0.095 × 10⁻³ mm²/s) than in c-EPI (0.135 × 10⁻³ mm²/s), p < 0.05.

Conclusions

PTX-accelerated EPI with spatially-selective excitation and reduced FOV leads to substantial improvements in DWI of the pancreas with respect to different aspects of image quality without significantly influencing the ADC values.     

The role of MR diffusion in differentiation of malignant and benign hepatic focal lesions

Aim

To determine if focal liver masses could be differentiated as benign or malignant by DWI and ADC maps.

Methods and materials

Sixty focal liver lesions were scanned using 1.5 T MRI. DWI was performed with b 0, b 500 and b 1000 gradients with ADC measurements. Comparison of mean ADC values between each benign and malignant lesion was done. Reference standard of diagnosis was obtained by correlating DWI with histopathologic findings and imaging follow-up. The accuracies of DWI and ADC values were assessed with the Student’s t test, and cut-off values were determined with receiver operating characteristic curve analysis.

Results

When ADC value of 1.0 × 10⁻³ mm²/s was used as a threshold value for differentiation of malignant tumors from benign lesions, sensitivity was 90.3%, specificity 78.57% and accuracy 86.7%. The best result was obtained with the use of ADC cut off value (at b 500) of 1.5 × 10⁻³ mm²/s and ADC cut off value (at b 1000) of 1.0 × 10⁻³ mm²/s, with 90.3% sensitivity, 92.86% specificity, 91.1% accuracy, 96.6% positive predictive value and 81.3% negative predictive value.

Conclusion

DWI and ADC map is a useful tool in differential diagnosis of malignant from benign liver lesions.     

Can high-b-value diffusion weighted imaging differentiate between pancreatic cancer,mass forming focal pancreatitis and normal pancreas?

Purpose

To investigate whether high-b-value diffusion weighted imaging (DWI) and the apparent diffusion coefficient (ADC) values can differentiate pancreatic cancer (PC), mass forming focal pancreatitis (MFFP), and normal pancreas.

Patients and methods

Diffusion weighted MR imaging (b = 0 and 800 s/mm²) was performed in 21 patients with histopathologically-proven pancreatic cancer, 19 patients with mass forming focal pancreatitis proven by histopathology and/or clinical follow up, and 21 normal control subjects. The signal intensity on DWI was visually evaluated and the ADC values of the pancreatic masses, the remaining pancreas, and the normal pancreas were measured and compared.

Results

On high-b-value (800 s/mm²) DW images, PC was slightly more hyperintense, relative to the remaining pancreas, than MFFP. The mean ADC value for PC (1.22 ± 0.101 × 10⁻³ mm²/s) was significantly lower than the remaining pancreas (1.99 ± 0.206 × 10⁻³ mm²/s; P < 0.001), MFFP (1.53 ± 0.122 × 10⁻³ mm²/s; P < 0.001), and the pancreatic gland in the control group (1.79 ± 0.061 × 10⁻³ mm²/s; P < 0.001). There was also a significant difference between the mean ADC values of MFFP and the remaining pancreas (1.53 ± 0.122 vs 1.89 ± 0.169 × 10⁻³ mm²/s; P < 0.001).

Conclusion

Differences on DWI and ADC measurements help to differentiate pancreatic cancer, mass forming focal pancreatitis, and normal pancreas.     

Contrast-enhanced dynamic and diffusion-weighted MR imaging at 3.0 T to assess aggressiveness of bladder cancer

Background

Diffusion weighted magnetic resonance imaging (DWI) and dynamic contrast-enhanced (DCE) MRI have been considered useful for pathological staging and histological grading in bladder cancer. To our knowledge, no study has combined the two imaging modalities together to assess aggressiveness of bladder cancer.

Objective

To assess the clinical aggressiveness of bladder cancer with DCE MRI and DWI at 3.0 T.

Materials and methods

A total of 59 patients with 69 pathologically confirmed tumor lesions were included in this study. All patients underwent MR examination at 3.0 T basing on DWI and DCE imaging. Tumor staging and histological grade were evaluated. The aggressiveness of bladder cancer was classified as low-, intermediate-, or high-aggressiveness according to its pathological phenotype. Apparent diffusion coefficient (ADC) value and semi-quantitative parameters (wash-in rate and wash-out rate) were determined. The correlation between clinical aggressiveness and ADC value, wash-in rate and wash-out rate were analyzed. In addition, the diagnostic accuracy of the diffusion and semi-quantitative parameters were estimated using receiver operating characteristic curve (ROC).

Results

Aggressiveness of bladder cancer is negatively correlated with ADC value (r = −0.705, p < 0.0001) and wash-out rate (r = −0.719, p < 0.0001). The tumor ADC value is positively correlated with wash-out rate (r = 0.555, p < 0.0001). The diagnostic specificity and accuracy using tumor ADC value and wash-out for the tumor with size <24 mm were better than that tumors with size ≥24 mm. The sensitivity, specificity and accuracy of ADC and wash-out rate in combination in diagnosis of bladder cancer aggressiveness were 96.7%, 94.9% and 95.7%, respectively. ROC curve revealed the diagnostic performance of aggressiveness of bladder cancer using ADC value and wash-out rate were 0.928 (cut-off value: 0.905 × 10⁻³ mm²/s) and 0.891 (cut-off value: 0.685 min⁻¹), respectively.

Conclusion

ADC and wash-out rate derived from DWI and DCE-MRI at 3.0 T have good potential to assess the aggressiveness of bladder cancer and the accuracy was greater for ADC than for semi-quantitative parameters.     

Diagnostic impact of echo planar diffusion-weighted magnetic resonance imaging (DWI) in musculoskeletal neoplastic masses using apparent diffusion coefficient (ADC) mapping as a quantitative assessment tool

Purpose

To evaluate the diagnostic impact of echo planar DW imaging in distinguishing benign from malignant musculoskeletal soft-tissue masses using ADC mapping as a quantitative assessment tool.

Patients and methods

We evaluated 73 tumors (21 bone tumors and 52 soft-tissue tumors). MR examinations were performed with a 1.5-T system. Diffusion-weighted single-shot EPI images were obtained in all patients. Apparent diffusion coefficients (ADCs) were calculated by using b factors of 0 and 1000 s/mm². ADC value measurements were compared with the histopathological findings.

Results

The average ADC of benign tumors was 1.86 ± 0.67 × 10⁻³ mm²/s, and that of malignant soft-tissue tumors was 0.97 ± 0.35 × 10⁻³ mm²/s. ADC value of malignant tumors was significantly lower than that of the benign tumor group (p < 0.0001). The highest ADC value was seen in the case of ganglion cyst (2.8 ± 0.23 × 10⁻³ mm²/s) and cystic neurofibroma (2.5 ± 0.04 × 10⁻³ mm²/s), and juxta cortical enchondroma (2.65 ± 0.36 × 10⁻³ mm²/s) while the lowest one was seen in aggressive fibromatosis (0.37 ± 0.05 × 10⁻³ mm²/s). For malignant soft-tissue masses, the highest ADC value was seen in mesenchymal chondrosarcoma (2.1 ± 0.32) liposarcoma (intermediate grade) (1.4 ± 0.21) while the lowest ADC value was seen in fibrosarcoma (high grade) (0.78 ± 0.14).

Conclusion

MR diffusion provides additional information to the routine MRI sequences rendering it an effective non-invasive tool in differentiating between benign and malignant soft-tissue tumors.     

Necrotic cervical nodes: Usefulness of diffusion-weighted MR imaging in the differentiation of suppurative lymphadenitis from malignancy

Purpose

The purpose of this study was to assess the efficacy of diffusion-weighted (DW) MR imaging for the differentiation between suppurative lymphadenitis and malignancy in necrotic cervical lymph nodes.

Materials and methods

Fifteen patients with suppurative lymphadenitis, 40 with squamous cell carcinoma (SCC), eight with lymphoma, and six with thyroid cancer were accompanied by necrotic cervical nodes. All 69 patients underwent 1.5-T MR imaging including DW and 58 underwent gadolinium-enhanced MR imaging. Necrotic area-to-spinal cord signal intensity ratios (SIR) on T1-, T2- and DW images and apparent diffusion coefficients (ADCs) [10⁻³ mm²/s] were correlated with the pathologies.

Results

Nineteen necrotic cervical nodes with suppurative lymphadenitis, 67 with SCC, 10 with lymphoma, and 12 with thyroid cancer were identified. SIR on DW images was higher in suppurative lymphadenitis (2.50 ± 1.21) than in malignancies (1.29 ± 0.67) (p < .01), and ADC value was lower in suppurative lymphadenitis (0.89 ± 0.21) than in malignancies (1.46 ± 0.46) (p < .01). SIR on T1-weighted images was higher in thyroid cancer (1.95 ± 0.53) than in suppurative lymphadenitis (0.87 ± 0.17), SCC (0.92 ± 0.13), and lymphoma (0.95 ± 0.09) (p < .01). No significant difference in SIR on T2-weighted images was found between suppurative lymphadenitis (1.46 ± 0.50) and malignancies (1.61 ± 0.56).

Conclusion

DW imaging with ADC measurements may play a supplementary role in the differentiation of necrotic cervical nodes between suppurative lymphadenitis and malignancy.     

ADC measurements in diffuse large B-cell lymphoma and follicular lymphoma: a DWI and cellularity study

Purpose

Diffusion-weighted magnetic resonance imaging (DW-MRI) allows quantifying the random motion of water molecules in tissue by means of apparent diffusion coefficient (ADC) measurements. The aim of the study was to determine whether ADC measurements allow discrimination of diffuse large B-cell lymphoma (DLBCL) from follicular lymphoma (FL), and to examine the relationship between cellularity and ADC value of the tumor using DWI.

Materials and methods

Thirty-two patients with histologically proven non-Hodgkin lymphoma (21 with DLBCL and 11 with FL, 17 males and 15 females, mean age 62 ± 13 years) underwent conventional MRI and DWI examination before treatment. The ADC values of DLBCL were compared to those of FL. The ADC value of the tumor was also correlated with the tumor tissue cellularity.

Results

The mean ADC value of DLBCL was not significantly different from that of FL (0.70 ± 0.16 × 10⁻³ mm²/s vs. 0.76 ± 0.12 × 10⁻³ mm²/s, P = 0.21). The cellularity of DLBCL was significantly lower than that of FL (2991 ± 351 cells/view vs. 4412 ± 767 cells/view, P < 0.001). There was no correlation between the ADC value and the tissue cellularity of the tumor in patients with DLBCL and FL.

Conclusion

ADC measurements could not differentiate between DLBCL and FL, and there was no correlation between the ADC value and cellularity of the tumor in patients with DLBCL and FL.