Diffusion‐weighted imaging of breast cancer: Correlation of the apparent diffusion coefficient value with prognostic factors

Purpose

To evaluate the role of diffusion‐weighted imaging (DWI) in the detection of breast cancers, and to correlate the apparent diffusion coefficient (ADC) value with prognostic factors.

Materials and Methods

Sixty‐seven women with invasive cancer underwent breast MRI. Histological specimens were analyzed for tumor size and grade, and expression of estrogen receptors (ER), progesterone receptors, c‐erbB‐2, p53, Ki‐67, and epidermal growth factor receptors. The computed mean ADC values of breast cancer and normal breast parenchyma were compared. Relationships between the ADC values and prognostic factors were determined using Wilcoxon signed rank test and Kruskal‐Wallis test.

Results

DWI detected breast cancer as a hyperintense area in 62 patients (92.5 %). A statistically significant difference in the mean ADC values of breast cancer (1.09 ± 0.27 × 10^?5 mm²/s) and normal parenchyma (1.59 ± 0.27 × 10^?5 mm²/s) was detected (P < 0.0001). There were no correlations between the ADC value and prognostic factors. However, the median ADC value was lower in the ER‐positive group than the ER negative group, and this difference was marginally significant (1.09 × 10^?5 mm²/s versus 1.15 × 10^?5 mm²/s, P = 0.053).

Conclusion

The ADC value was a helpful parameter in detecting malignant breast tumors, but ADC value could not predict patient prognosis. J. Magn. Reson. Imaging 2009;30:615–620. © 2009 Wiley‐Liss, Inc.

     

Diagnostic utility of diffusion‐weighted MR imaging and apparent diffusion coefficient value for the diagnosis of adrenal tumors

Purpose

To determine the utility of diffusion‐weighted MR imaging (DWI) for the diagnosis of adrenal tumors.

Materials and Methods

Forty‐two patients (24 men and 18 women; age, 61.5 ± 12.7 years old; range, 34–86 years) with 43 adrenal tumors (11 functioning cortical adenomas, 20 nonfunctioning cortical adenomas, 7 metastatic tumors, and 5 pheochromocytomas) were retrospectively investigated. DWIs were obtained by single‐shot spin‐echo type echo‐planar imaging sequence (1.5 Tesla [T]; TR = 8000 ms, TE = 72, b‐factor = 0 and 1000 s/mm²), and apparent diffusion coefficient (ADC) value was calculated. Chemical shift images were obtained by gradient echo sequence (TR = 161, TE = 2.38 [out‐of‐phase, OP] and 4.76 [in‐phase, IP], FA = 60), and the signal intensity index (SII; [IP‐OP]/IP *100%) was calculated.

Results

There was no difference in ADC values between adenomas (1.09 ± 0.29*10^?3 mm²/s; range, 0.52–1.64) and metastatic tumors (0.85 ± 0.26*10^?3; 0.51–1.23; p = 0.14). Pheochromocytomas showed the higher mean ADC value (1.59 ± 0.34*10^?3; 1.04–1.96) compared with those of adenomas or metastatic tumors (P < 0.05 and P < 0.005, respectively). The mean SII of adenomas (62.1 ± 17.9%; 14.5–88.4) was significantly higher than those of pheochromocytomas (4.0 ± 10.0%; ?19.6–3.3; P < 0.005) or metastatic tumors (?1.5 ± 11.7%; ?18.3–8.2; P < 0.01). There was no correlation between ADC values and SII.

Conclusion

Although pheochromocytomas showed higher ADC values, we did not find that ADC value had diagnostic utility for differentiating adenomas and metastatic tumors. J. Magn. Reson. Imaging 2009;29:112–117. © 2008 Wiley‐Liss, Inc.

     

Use of conventional MR imaging and diffusion‐weighted imaging for evaluating the risk grade of gastrointestinal stromal tumors

Purpose:

To study the risk grade of gastrointestinal stromal tumors (GISTs) with conventional MR imaging and diffusion‐weighted imaging (DWI).

Materials and Methods:

The abdominal MR images with DWI of 23 patients with pathologically proven GISTs during January 2010 to May 2011 were retrospectively reviewed. The conventional MR imaging findings and apparent diffusion coefficient (ADC) values of the tumors related to the risk grade were analyzed.

Results:

In the 23 patients, there were 13 patients with high‐risk, 5 with medium‐risk, 5 with low‐risk, and 0 with very low‐risk GISTs. Most of the conventional MR findings of the tumors did not correlate with the risk grade. The only exception to this was the correlation between risk grade and the enhancement degree of the tumor after Gd‐DTPA. The ADC values were, respectively, (1.04 ± 0.13) × 10^?3 mm²·s^?1, (1.59 ± 0.06) × 10^?3 mm²·s^?1 and (1.94 ± 0.08) × 10^?3 mm²·s^?1 (P < 0.05) in the high‐, medium‐, and low‐risk grade groups. The ADC values of GISTs decreased with the increase of the risk grade of the tumors (r = ?0.957; P < 0.05).

Conclusion:

DWI can be used to assess the risk grade of GISTs, but conventional MR imaging is of limited use. J. Magn. Reson. Imaging 2012; 36:1395–1401. © 2012 Wiley Periodicals, Inc.

     

Diffusion-weighted MRI of fatty liver

Purpose:

To investigate the effect of fat infiltration on the apparent diffusion coefficient (ADC) of liver, and assess the relationship between ADC and hepatic fat fraction (HFF).

Materials and Methods:

MRI scans of 120 consecutive patients were included in this retrospective study. Of these, 42 patients were included in the fatty liver group and 78 in the control group. ADC values were measured from a pair of diffusion‐weighted (DW) images (b = 0 mm²/s and 1000 mm²/s). HFFs were measured using T1W GRE dual‐echo images. The difference between the ADCs of the two groups was assessed with the t‐test. The relationship between HFF and ADC was determined using linear regression analysis and the Pearson correlation coefficient (r).

Results:

Mean HFFs were 0.85 ± 2.86 and 13.67 ± 8.62 in the control and fatty liver groups, respectively. The mean ADC of fatty liver group 1.20 ± 0.22 × 10^?3 mm²/s was significantly lower than that of the control group 1.32 ± 0.23 × 10^?3 mm²/s (P = 0.02). Linear regression analysis revealed an inverse relationship between ADC and HFF (r = ?0.39, P < 0.0001).

Conclusion:

ADC significantly decreases in patients with >5% HFF, and ADC and HFF exhibit an inverse relationship. J. Magn. Reson. Imaging 2012;35:1109‐1111. © 2011 Wiley Periodicals, Inc.

     

Initial experience of 3 tesla apparent diffusion coefficient values in differentiating benign and malignant thyroid nodules

Purpose:

To evaluate the role of diffusion‐weighted magnetic resonance imaging (DWMRI) in differentiating benign and malignant thyroid nodules using a 3 Tesla (T) MRI scanner.

Materials and Methods:

Twenty‐eight nodules in 25 patients and 14 healthy control cases were included in the study. DWMRI was acquired with 6 b values with a 3T MRI scanner. The apparent diffusion coefficient (ADC) values of the nodules were calculated from reconstructed ADC map images and were compared with the final histopathological diagnoses.

Results:

The mean ADC value of the benign nodules was 1548 ± 353.4 (×10^?6 mm²/s), and the mean ADC of the malignant nodules was 814 ± 177.12 (×10^?6 mm²/s). The normal thyroid tissue had a mean ADC value of 1323.43 ± 210.35 × 10^?6 mm²/s (958–1689 × 10^?6 mm²/s) in the healthy control group. The ADC values were significantly different among the three groups (P = 0.001). An ADC value of 905 × 10^?6 mm²/s was determined to be the cutoff value for differentiating benign and malignant nodules, with 90% (55.5–98.3) sensitivity and 100% (81.3–100.0) specificity.

Conclusion:

This study suggests that the ADC values of nodules measured with a 3T MRI scanner could help in differentiating benign thyroid nodules from malignant nodules. J. Magn. Reson. Imaging 2013;37:1077–1082. © 2012 Wiley Periodicals, Inc.

     

Assessment of mediastinal tumors with diffusion‐weighted single‐shot echo‐planar MRI

Purpose

To assess the role of diffusion‐weighted single‐shot echo‐planar magnetic resonance imaging (MRI) in patients with mediastinal tumors.

Methods

Prospective study was conducted on 45 consecutive patients (29 male, 16 female, age 22–66 years, mean 41 years) with mediastinal tumor. They underwent diffusion‐weighted single‐shot echo‐planar MRI of the mediastinum with a b‐factor of 0, 300, and 600 sec/mm². The apparent diffusion coefficient (ADC) value of the mediastinal tumor was correlated with the histopathological findings.

Results

The mean ADC value of malignant mediastinal tumors was 1.09 ± 0.25 × 10^?3 mm²/sec, and of benign tumors was 2.38 ± 0.56 × 10^?3 mm²/sec. There was a significant difference in the mean ADC value between malignant and benign tumors (P = 0.001) and within different grades of malignancy (0.001). When an ADC value of 1.56 × 10^?3 mm²/sec was used as a threshold value for differentiating malignant from benign tumor, the best results were obtained with an accuracy of 95%, sensitivity of 96%, specificity of 94%, positive predictive value of 94%, negative predictive value of 96%, and area under the curve of 0.938.

Conclusion

The ADC value is a noninvasive parameter that can be used for differentiation of malignant from benign mediastinal tumors and grading of mediastinal malignancy. J. Magn. Reson. Imaging 2009. © 2009 Wiley‐Liss, Inc.

     

Diffusion‐weighted imaging of the healthy pancreas: ADC values are age and gender dependent

Purpose:

To investigate the healthy pancreas with diffusion‐weighted imaging (DWI) for characterization of age and gender‐related differences in apparent diffusion coefficient (ADC) values.

Materials and Methods:

Sixty six volunteers were prospectively enrolled (33 male, 33 female; range 1.4 to 83.7 years of age) and echo‐planar DWI of the pancreas was performed. ADC values were measured in the pancreas head, body, and tail using a pixel‐by‐pixel approach. Effects of age and gender on ADC values were analyzed using a two‐factorial multivariate analysis of variance (MANOVA).

Results:

ADC values correlated inversely with the age of the volunteers. The mean global pancreatic ADC values (× 10^?3 mm²/s) in the age groups 0–20 years, 21–40 years, and > 40 years were 1.18 ± 0.19, 1.07 ± 0.13, and 0.99 ± 0.18, respectively. Female individuals had higher mean global ADC values than male (1.13 ± 0.14 versus 1.02 ± 0.18 × 10^?3 mm²/s). MANOVA showed significant effects of age (P value 0.022, eta² = 0.13) and gender (P value 0.001, eta² = 0.28) on ADC values.

Conclusion:

Pancreatic ADC values decline with ageing and show significant gender differences with higher mean values in females. The awareness of baseline values adjusted to age and gender will be important for correct interpretation of individual cases and design of future studies. J. Magn. Reson. Imaging 2013;37:886–891. © 2012 Wiley Periodicals, Inc.

     

Differential diagnosis of mammographically and clinically occult breast lesions on diffusion‐weighted MRI

Purpose:

To investigate the diagnostic performance of diffusion‐weighted imaging (DWI) for mammographically and clinically occult breast lesions.

Materials and Methods:

The study included 91 women with 118 breast lesions (91 benign, 12 ductal carcinoma in situ [DCIS], 15 invasive carcinoma) initially detected on dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) and assigned BI‐RADS category 3, 4, or 5. DWI was acquired with b = 0 and 600 s/mm². Lesion visibility was assessed on DWI. Apparent diffusion coefficient (ADC) values were compared between malignancies, benign lesions, and normal (no abnormal enhancement on DCE‐MRI) breast tissue, and the diagnostic performance of DWI was assessed based on ADC thresholding.

Results:

Twenty‐four of 27 (89%) malignant and 74/91 (81%) benign lesions were hyperintense on the b = 600 s/mm² diffusion‐weighted images. Both DCIS (1.33 ± 0.19 × 10^?3 mm²/s) and invasive carcinomas (1.30 ± 0.27 × 10^?3mm²/s) were lower in ADC than benign lesions (1.71 ± 0.43 × 10^?3mm²/s; P < 0.001), and each lesion type was lower in ADC than normal tissue (1.90 ± 0.38 × 10^?3mm²/s, P ≤ 0.001). Receiver operating curve (ROC) analysis showed an area under the curve (AUC) of 0.77, and sensitivity = 96%, specificity = 55%, positive predictive value (PPV) = 39%, and negative predictive value (NPV) = 98% for an ADC threshold of 1.60 × 10^?3mm²/s.

Conclusion:

Many mammographically and clinically occult breast carcinomas were visibly hyperintense on diffusion‐weighted images, and ADC enabled differentiation from benign lesions. Further studies evaluating DWI while blinded to DCE‐MRI are necessary to assess the potential of DWI as a noncontrast breast screening technique. J. Magn. Reson. Imaging 2010;1:562–570. © 2010 Wiley‐Liss, Inc.

     

Ability of diffusion-weighted imaging for the differential diagnosis between chronic expanding hematomas and malignant soft tissue tumors

Purpose

To evaluate the potential of diffusion‐weighted imaging (DWI) in distinguishing chronic expanding hematomas (CEHs) from malignant soft tissue tumors.

Materials and Methods

We performed conventional MRI and DWI of six CEHs and 31 malignant soft tissue tumors from 37 patients seen between May 2000 and November 2006. DWI was obtained with a single‐shot echo‐planar imaging (EPI) sequence using a 1.5T MR imager. The mean apparent diffusion coefficient (ADC) value was also calculated. We evaluated MRI findings of CEHs and compared ADC value of CEHs with malignant soft tissue tumors.

Results

On conventional MRI, two of six CEHs were difficult to differentiate from malignant soft tissue tumors based on imaging findings. The mean ADC value of CEHs and malignant soft tissue tumors was 1.55 ± 0.121 × 10^?3 mm²/sec and 0.92 ± 0.139 × 10^?3 mm²/sec (mean ± SD), respectively. The mean ADC value of CEHs was significantly higher than that of malignant soft tissue tumors (P < 0.01). There was no overlap in the minimum ADC values among CEHs and malignant soft tissue tumors.

Conclusion

DWI is useful for differentiating between CEHs and malignant soft tissue tumors. J. Magn. Reson. Imaging 2008;28:1195–1200. © 2008 Wiley‐Liss, Inc.

     

Characterization of chondroblastic osteosarcoma: Gadolinium‐enhanced versus diffusion‐weighted MR imaging

Purpose

To detect differences in magnetic resonance imaging (MRI) between chondroblastic osteosarcoma and the other types of osteosarcomas or chondrosarcomas using gadolinium‐enhanced versus diffusion‐weighted sequences.

Materials and Methods

Contrast‐enhanced MRI and diffusion‐weighted imaging (DWI) were performed in five chondroblastic osteosarcoma (CO) cases, 17 other types of osteosarcomas (OS), and 18 chondrosarcomas (CS). DWI was obtained with a single‐shot echo‐planar imaging (EPI) sequence using a 1.5T MR imager. The apparent diffusion coefficients (ADCs) of the minimum and maximum values were also obtained. The contrast‐enhancement pattern was evaluated and minimum‐maximum ADC value of CO was compared with other types of OS and CS.

Results

Both CO and CS showed a similar enhancement pattern; both showed septonodular and peripheral rim enhancement. The minimum ADC value of CO (1.24 ± 0.10 × 10^?3mm²/sec) was significantly higher than that of other types of OS (0.84 ± 0.15 × 10^?3mm²/sec) and was significantly lower than that of CS (1.64 ± 0.20 × 10^?3mm²/sec). In addition, the maximum ADC value of CO (2.28 ± 0.20 × 10^?3mm²/sec) was significantly higher than that of other types of OS (1.33 ± 0.26 × 10^?3mm²/sec).

Conclusion

DWI appears to be more useful for differentiating between chondroblastic osteosarcoma and chondrosarcoma or other types of osteosarcoma than Gd‐enhanced MRI. J. Magn. Reson. Imaging 2009;29:895–900. © 2009 Wiley‐Liss, Inc.

     

High-grade bladder cancer: association of the apparent diffusion coefficient with metastatic disease: preliminary results

Purpose:

To assess the utility of apparent diffusion coefficient (ADC) values obtained from diffusion‐weighted imaging (DWI) in distinguishing high‐grade bladder cancer with and without metastatic disease.

Materials and Methods:

Seventeen patients with histologically confirmed high‐grade bladder cancer who underwent pelvic magnetic resonance imaging (MRI) at 1.5T including DWI using b‐values of 0, 400, and 800 sec/mm² were assessed. Histologic findings and follow‐up imaging were used to establish the reference standard in terms of metastatic disease. Two radiologists independently recorded ADC of all lesions following a training session, with their results averaged. Mann–Whitney U‐test, receiver operating characteristic (ROC) curve analysis and intraclass correlation coefficient (ICC) were used for data analysis.

Results:

Metastatic disease was characterized as present or absent in eight and nine patients, respectively. ADC was significantly lower among cases with metastatic disease than among cases without metastatic disease, both within the entire cohort (1.07 ± 0.18 × 10^?3 mm²/s vs. 1.45 ± 0.22 × 10^?3 mm²/s; P = 0.002) and within the subset of patients with muscle‐invasive tumor (1.06 ± 0.19 × 10^?3 mm²/s vs. 1.45 ± 0.23 × 10^?3 mm²/s; P = 0.017). Area under the ROC curve for identifying metastatic disease using ADC was 0.944, with optimal threshold of 1.21 × 10^?3 mm²/s, which was associated with a sensitivity of 87.5%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 90.0%. Interreader agreement for ADC was excellent (ICC = 0.91).

Conclusion:

In this preliminary study, ADC was significantly different between cases of high‐grade urothelial carcinoma of the bladder with and without metastatic disease. These results may have value in assessing the metastatic potential of patients with localized high‐grade tumors of the bladder. J. Magn. Reson. Imaging 2012;35:1478–1483. © 2012 Wiley Periodicals, Inc.

     

Navigator respiratory‐triggered diffusion‐weighted imaging in the follow‐up after hepatic radiofrequency ablation—initial results

Purpose

To evaluate diffusion alterations after hepatic radiofrequency (RF) ablation using a navigator respiratory‐triggered diffusion‐weighted imaging (NRT‐DWI) sequence with regard to potential diagnostic information for detection of local tumor progression (LTP).

Materials and Methods

One hundred forty‐eight consecutive follow‐up magnetic resonance (MR) examinations of 54 patients after hepatic RF ablation were reviewed. Apparent diffusion coefficient (ADC) values of ablation zones and liver parenchyma were assessed using a single‐shot echoplanar imaging sequence with the NRT technique. ADC values of ablation zones and adjacent signal alterations identified in NRT‐DWI were analyzed with regard to LTP.

Results

Mean ADC values of ablation zones (119.9 ± 30.5 × 10^?5 mm²/sec) and liver (106.3 ± 21.2 × 10^?5 mm²/sec) differed significantly (P = 0.0003). No evident changes in ablations' ADC values over time could be identified. ADC values obtained from the entire ablation zone did not significantly differ regarding the presence of LTP. In 58 examinations, hyperintense areas in the periphery of the ablation zone were detected on the NRT‐DWI. Corresponding ADC values were significantly lower in patients with LTP (102.1 ± 22.4 versus 130.8 ± 47.6 × 10^?5 mm²/sec; P = 0.0124).

Conclusion

NRT‐DWI is useful in the follow‐up imaging after RF ablation. ADC‐based evaluation of signal alterations adjacent to the ablation zone may contribute to the identification of LTP and nontumoral posttreatment tissue changes. J. Magn. Reson. Imaging 2009. © 2009 Wiley‐Liss, Inc.

     

Diffusion-weighted imaging of the healthy pancreas: apparent diffusion coefficient values of the normal head, body, and tail calculated from different sets of b-values

Purpose:

To evaluate differences in apparent diffusion coefficient (ADC) values between head, body, and tail regions and the impact of sets of b‐values used in diffusion weighted imaging (DWI) of the normal pancreas.

Materials and Methods:

In 51 healthy volunteers echo‐planar DWI of the pancreas was prospectively performed with b‐values of 50, 400, and 800 s/mm². All four possible combinations of b‐values were used to calculate ADC values in a total of 587 regions in the pancreas head, body, and tail regions. Dependency of ADC values on the anatomical regions and on the applied sets of b‐values was calculated using multivariate analysis of variance (ANOVA).

Results:

Mean ADC values differed significantly between the anatomical regions with the lowest values measured in the pancreatic tail (head 1.13 ± 0.20, body 1.05 ± 0.20, and tail 0.94 ± 0.18 × 10^?3 mm²/s; P < 0.05). ANOVA showed no dependency of ADC values on the sets of b‐values used.

Conclusion:

ADC values differed significantly between the pancreatic head, body, and tail region, with decreasing ADC values toward the tail. Cautious interpretation of DWI results with adjusted, normalized values adapted to the anatomical region seems advisable. The knowledge of such differences may enhance the method's capability to differentiate between different pancreatic pathologies. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.

     

Diffusion‐weighted images differentiate benign from malignant thyroid nodules

Purpose:

To reveal the possible role of diffusion‐weighted images (DWI) in the differential diagnosis of benign and malignant thyroid nodules by comparing the results of fine‐needle aspiration cytology (FNAC).

Materials and Methods:

In an 18‐month period (December 2005 to May 2007), 27 cases with benign thyroid nodules with a total of 52 benign nodules, nine cases with thyroid gland malignancy, and 24 healthy control cases were included in the study. Cases that were indicated to undergo to FNAC examination and sent by a clinician for biopsy to the radiology unit were included in the study to assess the cytopathologic confirmation of the clinic, ultrasonographic, and magnetic resonance imaging (MRI) findings.

Results:

The mean apparent diffusion coefficient (ADC) values of thyroid nodules were 2745.3 ± 601.1 × 10^?6 mm²/s (1605–3899 × 10^?6mm²/s) in the benign group and 695.2 ± 312.5 × 10^?6mm²/s (165–1330 × 10^?6mm²/s) in the malignant group. Normal thyroid tissues had mean ADC values of 1344.1 ± 276.4 × 10^?6 mm²/s (1015–1764 × 10^?6mm²/s). The ADC values of three subgroups were significantly different (P = 0.0001). A reduced ADC was observed in most types of malignant tumors due to the consequent decrease of the extracellular extravascular space.

Conclusion:

Our preliminary results showed that ADC values of nodules may provide useful data about the nature of a thyroid nodule. J. Magn. Reson. Imaging 2010;31:94–100. © 2009 Wiley‐Liss, Inc.

     

Diffusion‐weighted imaging of prostate cancer: Correlation between apparent diffusion coefficient values and tumor proliferation

Purpose

To investigate whether the apparent diffusion coefficient (ADC) values of prostate cancer (PCa) are able to reflect tumor proliferation.

Materials and Methods

The clinical and pathological information for 38 patients with PCa and 33 patients with benign prostate hyperplasia (BPH) were studied. Examination of the patients was performed using a 1.5 T superconducting magnetic scanner equipped with a pelvic phased‐array multicoil. Diffusion‐weighted images (DWIs) were acquired using an echo‐planar imaging sequence. The ADC values of PCa, BPH, and peripheral zone (PZ) were calculated. The cellularity of PCa was recorded based on hematoxylin and eosin staining. The proliferating cell nuclear antigen (PCNA) was detected using an immunohistochemical technique.

Results

The ADC values of PCa, BPH, and PZ were 49.32 ± 12.68 × 10^?5 mm²/s, 86.73 ± 26.75 × 10^?5 mm²/s, and 126.25 ± 27.21 × 10^?5 mm²/s, respectively. The ADC values of PCa were lower than those of BPH and PZ (P < 0.05). The cellularity and PCNA labeling index (LI) of PCa were higher than those of BPH (P < 0.05). The ADC values of PCa were negatively correlated with those of cellularity and PCNA LI (r = ?0.646 and ?0.446, respectively; P < 0.05).

Conclusion

The ADC values of PCa can reveal the differences in proliferative activity between PCa and BPH. These values are therefore able to predict the proliferative rate of variously differentiated prostate cancers. J. Magn. Reson. Imaging 2009;29:1360–1366. © 2009 Wiley‐Liss, Inc.

     

Diffusion-weighted magnetic resonance imaging in the detection of testicular torsion: feasibility study

Purpose:

To investigate the feasibility and usefulness of diffusion‐weighted magnetic resonance imaging in the detection of testicular torsion.

Materials and Methods:

Institutional Review Board approval and informed consent from all participants were obtained. Consecutive 28 patients with acute scrotal symptoms were included in this study. Fat‐suppressed T2‐weighted, dynamic subtraction contrast‐enhanced, and diffusion‐weighted images were obtained in the coronal plane with a 1.5 T MR unit. An apparent diffusion coefficient (ADC) map was reconstructed from the diffusion‐weighted images obtained with b‐factor of 0 and 800 s/mm². Comparisons of ADC values between the affected and nonaffected testes were performed with Mann–Whitney's U‐test.

Results:

Diffusion‐weighted and ADC images with diagnostic quality were obtained in 23 out of the 28 patients (82%). In testicular torsion (n = 9), the mean ADC value of the twisted testes was significantly lower than that of the nonaffected testes (0.750 ± 0.297 vs. 1.017 ± 0.165 × 10^?3 mm²/sec, P < 0.05). In other scrotal disorders (n = 14), there was no significant difference in the mean ADC value of the testes between the affected and nonaffected side (P = 0.655). The affected‐to‐nonaffected ratio of ADC value was significantly lower in testicular torsion than that in other scrotal disorders (P < 0.05).

Conclusion:

Diffusion‐weighted imaging of the scrotum with testicular ADC measurement can allow for the detection of testicular torsion without any use of contrast media. J. Magn. Reson. Imaging 2011;. © 2011 Wiley Periodicals, Inc.

     

Peripheral hyperintense pattern on T2-weighted magnetic resonance imaging (MRI) in breast carcinoma: correlation with early peripheral enhancement on dynamic MRI and histopathologic findings

Purpose

To assess the value of magnetic resonance (MR) diffusion‐weighted imaging (DWI) in the evaluation of deep infiltrating endometriosis (DIE).

Materials and Methods

In a prospective single‐center study, DWI was added to the standard MRI protocol in 56 consecutive patients with known or suspected endometriosis. Endometriotic lesions as well as (functional) ovarian cysts were analyzed for location, size, and signal intensity on T1, T2, and DWI. Apparent diffusion coefficient (ADC) values were calculated using b‐values of 50, 400, 800, and 1200 s/mm². Statistical analysis included the Spearman correlation coefficient, Mann–Whitney U, and Kruskal–Wallis tests.

Results

A total of 112 lesions (62 endometrial cysts and 48 DIE) were detected, 60 of which were large enough to analyze. Mean ADC values of endometrial cysts and functional ovarian cysts were 1.11 × 10^?3/mm²/s and 2.14 × 10^?3/mm²/s, respectively. Mean ADC values of DIE retrocervical, infiltrating the colon, and bladder were 0.70 × 10^?3/mm²/s, 0.79 × 10^?3/mm²/s, and 0.76 × 10^?3/mm²/s, respectively. ADC values of DIE did not show a significant difference between varying pelvic locations (P = 0.63).

Conclusion

Results of our study suggest that ADC values of DIE are consistently low, without significant difference between pelvic locations. J. Magn. Reson. Imaging 2010;31:1117–1123. © 2010 Wiley‐Liss, Inc.

     

Quantitative cerebral MR perfusion imaging: preliminary results in stroke

Purpose:

To demonstrate that OKN007, a disulfonyl derivative of phenyl‐tert‐butyl nitrone (PBN), has anti‐glioma activity in the clinically relevant C6 rat glioma model using multi‐parametric magnetic resonance imaging.

Materials and Methods:

Twenty‐one rats were intracerebrally implanted with C6 cells and administered OKN007 or kept as controls. Animals were monitored with MRI at 7 Tesla (T), using morphologic, diffusion‐weighted and perfusion imaging, followed by histology and Western blots of angiogenesis and inflammatory markers.

Results:

OKN007 was found to decrease tumor volumes and increase survival. The glioma tissues of OKN007‐treated rats were found to have longitudinal apparent diffusion coefficients (ADC_z) of 0.76 ± 0.06 × 10^?3 mm²/s, similar to the contralateral tissue and significantly smaller than untreated gliomas (0.97 ± 0.13 × 10^?3 mm²/s). They had higher perfusion rates (66 ± 4 mL/100 g·min) than untreated gliomas (26 ± 7 mL/100 g·min). All examined molecular markers were decreased in OKN007‐treated rat gliomas, compared with elevated levels in untreated rats.

Conclusion:

MRI assessment was successfully used to monitor a decrease in tumor growth, and corresponding alterations in ADC and perfusion rates in rat C6 gliomas treated with the anti‐glioma agent, OKN007. J. Magn. Reson. Imaging 2010;31:796–806. ©2010 Wiley‐Liss, Inc.

     

Impact of blood flow on diffusion coefficients of the human kidney: A time‐resolved ECG‐triggered diffusion‐tensor imaging (DTI) study at 3T

Purpose:

To evaluate the impact of renal blood flow on apparent diffusion coefficients (ADC) and fractional anisotropy (FA) using time‐resolved electrocardiogram (ECG)‐triggered diffusion‐tensor imaging (DTI) of the human kidneys.

Materials and Methods:

DTI was performed in eight healthy volunteers (mean age 29.1 ± 3.2) using a single slice coronal echoplanar imaging (EPI) sequence (3 b‐values: 0, 50, and 300 s/mm²) at the timepoint of minimum (20 msec after R wave) and maximum renal blood flow (200 msec after R wave) at 3T. Following 2D motion correction, region of interest (ROI)‐based analysis of cortical and medullary ADC‐ and FA‐values was performed.

Results:

ADC‐values of the renal cortex at maximum blood flow (2.6 ± 0.19 × 10^?3 mm²/s) were significantly higher than at minimum blood flow (2.2 ± 0.11 × 10^?3 mm²/s) (P < 0.001), while medullary ADC‐values did not differ significantly (maximum blood flow: 2.2 ± 0.18 × 10^?3 mm²/s; minimum blood flow: 2.15 ± 0.14 × 10^?3 mm²/s). FA‐values of the renal medulla were significantly greater at maximal blood (0.53 ± 0.05) than at minimal blood flow (0.47 ± 0.05) (P < 0.01). In contrast, cortical FA‐values were comparable at different timepoints of the cardiac cycle.

Conclusion:

ADC‐values in the renal cortex as well as FA‐values in the renal medulla are influenced by renal blood flow. This impact has to be considered when interpreting renal ADC‐ and FA‐values. J. Magn. Reson. Imaging 2013;37:233–236. © 2012 Wiley Periodicals, Inc.

     

Mediastinal lymph nodes: Assessment with diffusion‐weighted MR imaging

Purpose

To prospectively determine whether the diffusion‐weighted magnetic resonance imaging is useful to distinguish between malignant and benign mediastinal lymph nodes.

Materials and Methods

Thirty‐five patients (14 women, 21 men; mean age 52 years) with 91 lymph nodes in the mediastinum detected by computed tomography underwent 1.5 Tesla (T) diffusion‐weighted MR imaging before mediastinoscopy (n = 29) and mediastinotomy (n = 6). Diffusion‐weighted MR images were acquired with a b factor of 50, and 400 s/mm² using single‐shot echo‐planar sequence.

Results

Of the 35 patients, 18 had diagnosis of malignant tumor. Of the 18 patients with tumor, 8 had nonsmall cell carcinoma, and 10 had small cell carcinoma. Ninety‐one mediastinal lymph nodes were detected in the 35 untreated patients: 19 were pathologically diagnosed as metastatic lymph nodes, and 72 lymph nodes were diagnosed as nonmetastatic lymph nodes, including 50 sarcoidosis, 14 reactive lymphoid hyperplasia, and 8 necrotizing granulamatous lymphadenitis. The apparent diffusion coefficient (ADC) was significantly lower in metastatic lymph nodes (1.012 ± 0.025 × 10^?3 mm²/s; P < 0.0005) than in benign lymph nodes (1.511 ± 0.075 × 10^?3 mm²/s). On the ADC map, malignant nodes showed hyperintense (n = 2, 10.52%), hypointense (n = 14, 73.68%), and mixed intensity (n = 3; 15.78%), whereas benign nodes showed hyperintense (n = 57; 79.16%), hypointense (n = 3; 41.6%), isointense (n = 6; 8.33%), and mixed intensity (n = 6; 8.33%).

Conclusion

Diffusion‐weighted MR with ADC value and signal intensity can be useful in differentiation of malignant and benign mediastinal lymph nodes. J. Magn. Reson. Imaging 2009;30:292–297. © 2009 Wiley‐Liss, Inc.