Equivalent cross-relaxation rate imaging of axillary lymph nodes in breast cancer

Equivalent cross-relaxation rate imaging and diffusion weighted imaging for early prediction of response to bevacizumab-containing treatment in colorectal liver metastases-preliminary study

PURPOSE

To evaluate and compare the usefulness of equivalent cross-relaxation rate (ECR) imaging (ECRI) and diffusion-weighted imaging (DWI) in the early prediction of the response of bevacizumab-containing treatments of colorectal liver metastases.

METHODS AND MATERIAL

Seven patients received bevacizumab-containing treatments for colorectal liver metastases. Serial magnetic resonance imaging was performed to evaluate responses before and 2 weeks after starting chemotherapy. In the ECRI, we adopted the off-resonance technique for preferential saturation of immobile protons to evaluate the ECR values. A single saturation transfer pulse frequency was used at a frequency of 3.5 ppm downfield from the water resonance. In the DWI, the apparent diffusion coefficient (ADC) value commonly used with two b-values was acquired by using diffusion weightings of 0 and 800 s/mm². The region of interest of the metastatic lesions in the liver was separately measured by ECRI and DWI. Tumor response was assessed by response evaluation criteria in solid tumors criteria 8 weeks after starting chemotherapy.

RESULTS

In this study, we had four responders and three nonresponders. There was a significant difference in the pretreatment ECR values between the responders and nonresponders (P=.01); there was no significant difference in the ADC values between the two groups. Analysis of the percentage difference between the pretreatment and post-treatment values, termed as percentage change, showed that there were no significant differences in the percentage change of the ADC values between both groups; however, the percentage change in the ECR value was significantly greater for the responders than for the nonresponders (-41.6%±17.1% vs. -12.9%±6.9%, respectively; P=.04).

CONCLUSION

The pretreatment ECR value and percentage change of the ECR value 2 weeks after starting chemotherapy were useful parameters in the early prediction of response to bevacizumab-containing treatment in colorectal liver metastases.

Correlation between equivalent cross-relaxation rate and cellular density in soft tissue tumors

OBJECTIVE

Equivalent cross-relaxation rate (ECR) imaging (ECRI), which allows quantitation of macromolecular tissue components, is a potentially useful nuclear magnetic resonance (NMR) technique for histopathological diagnosis. The purpose of this study was to compare ECR values among various histological types and assess the correlation between ECR and tumor cellular image in soft tissue tumors.

MATERIALS AND METHODS

We performed ECRI to evaluate cellular images of soft tissue tumors and tumorous lesions. Thirty-three patients who underwent evaluation with MRI and ECRI at the first visit were enrolled. Resection or biopsy was performed to obtain a histopathological diagnosis, followed by cell density measurement. ECR values of the histological subgroups were compared, and the correlation between ECR and cell density was analyzed to assess whether ECR can be used as an indicator of histological cell density.

RESULTS

ECR values for benign tumors varied widely and were not significantly different from those for malignant tumors. However, the mean ECR value was significantly higher for high-grade malignant tumors than for low-grade tumors (p < 0.01). Moreover, a positive correlation was found between ECR and cell density (r s = 0.72; p < 0.01).

CONCLUSIONS

ECR reflects the cell density and malignancy grade of a soft tissue tumor. ECRI could provide cellular imaging and useful clinical information to aid the pre-operative diagnosis of soft tissue tumors.

Equivalent cross-relaxation rate imaging positively correlates with pathological grade and cell density of adipocytic tumors

OBJECTIVE

Equivalent cross-relaxation rate imaging (ECRI) is an MRI technique used to evaluate qualitative changes in protein-water interactions. We aimed to prospectively evaluate the utility of ECRI for classification of adipocytic tumors.

MATERIALS AND METHODS

Institutional Review Board approval was obtained and all patients provided informed consent. Study participants included 40 patients with adipocytic tumors who were diagnosed with lipomas (n=22), atypical lipomatous tissue/well-differentiated liposarcoma (ALT/WDL; n=9), myxoid/round cell liposarcoma (MyL; n=6), and dedifferentiated liposarcoma (DDL; n=3), and 20 control patients for whom subcutaneous fat in the buttock or thigh was analyzed.

RESULTS

Mean ECR values of lipomas, ALT/WDL, and subcutaneous fat were low, and those of MyL and DDL were high. Mean ECR values of MyL and DDL were significantly higher than those of ALT/WDL. The cut-off value was 5.1%. There was a positive correlation between ECR value, pathological grade, and cell density in adipocytic tumors.

CONCLUSION

The ECR value positively correlates with pathological grade and cell density of adipocytic tumors. Our findings suggest that ECRI is a useful method for preoperative evaluation of adipocytic tumors.

Evaluation of parotid gland function using equivalent cross-relaxation rate imaging applied magnetization transfer effect

Safe imaging modalities are needed for evaluating parotid gland function. The aim of this study was to validate the utility of a magnetic resonance imaging (MRI) tool, equivalent cross-relaxation rate imaging (ECRI), as a measurement of parotid gland function after chemoradiotherapy. Subjects comprised 18 patients with head-neck cancer who underwent ECRI and salivary gland scintigraphy. First, we calculated ECR values (signal intensity on ECRI), maximum uptake rate (MUR) and washout rate (WOR) from salivary gland scintigraphy data at the parotid glands. Second, we investigated correlations between ECR values and each parameter of MUR (uptake function) and WOR (secretory function) obtained by salivary gland scintigraphy at the parotid gland. Next, we investigated each dose-response for ECR, MUR and WOR at the parotid gland. A correlation was detected between ECR values and MUR in both the pre- (r = -0.55, p < 0.01) and post-treatment (r = -0.50, p < 0.05) groups. A significant post-treatment correlation was detected between the percentage change in ECR values at 3-5 months after chemoradiotherapy and median dose to the parotid gland (Pearson correlation, r = -0.62, p < 0.05). However, no correlations were detected between median dose to the parotid gland and either MUR or WOR. ECRI is a new imaging tool for evaluating the uptake function of the parotid gland after chemoradiotherapy.

Cellular Imaging Using Equivalent Cross-Relaxation Rate Technique in Rabbit VX-2 Tumor Model

Purpose:

Equivalent cross-relaxation rate (ECR) imaging (ECRI) is a measurement technique that can be used to quantitatively evaluate changes in structural organization and cellular density by MRI. The aim of this study was to evaluate the correlation between the ECR value and cellular density in the rabbit VX2 tumor model.

Materials and methods:

Five rabbits implanted with 10 VX2 tumors in the femur muscles were included in this study. We adopted the off-resonance technique with a single saturation transfer pulse frequency of 7 ppm downfield from water resonance. The ECR value was defined as the percentage of signal loss between the unsaturated and saturated images. ECR images were constructed based on the percentage of the ECR value. Pathological specimens were divided into 34 areas and classified into two groups: the viable group and the necrotic group. ECR values were measured and compared between groups. The correlation between the ECR value and cellular density was then determined.

Results:

The mean ECR value was significantly higher in the viable group than in the necrotic group (61.2% vs. 35.8%). The area under the curve that calculated by receiver operating characteristic curve was 0.991 at 7 ppm. The regression graph showed a linear relationship between the ECR value and cellular density; the correlation coefficient (r) was 0.858.

Conclusion:

There is a strong association between the ECR value and cellular density in VX2 tumors and so ECRI could be a potentially useful technique for accurately depicting viable and necrotic areas.

Comparative 1H NMR studies of saturation transfer in copolymer gels and mouse lenses

Saturation transfer in cross-linked copolymer gels and excised intact and perforating trauma-induced cataract mouse lenses (4- or 8-week-old) were studied using intermolecular cross-relaxation rates (1/T(IS)(H(2)O); 1/T(IS)), monitored with f(2)-irradiation at -8.79, -4.00, and 7.13 ppm (gammaH(2)/2pi approximately 69 Hz). [1] The 1/T(IS)(7.13 ppm) vs dry weight [W (%)] profiles for hydrophilic copolymer gels were far steeper than those for hydrophobic copolymer gels, indicating the participation of an amount of bound water and a number of copolymer hydroxyl groups in the saturation transfer process. In contrast, the 1/T(IS)(-8.79 ppm) vs W (%) profiles exhibited little difference between the hydrophilic and hydrophobic copolymer gels, indicating the major participation of molecular rigidity, i.e. W (%) in the saturation transfer process. [2] The 1/T(IS)(7.13 ppm) values for cataractous mouse lenses were larger than those for intact lenses, indicating the formation of large, immobile lens protein associates or aggregates containing a sufficient amount of bound water for the saturation transfer. [3] The 1/T(IS)(7.13 ppm) vs W (%) profiles for the hydrophilic copolymer gels exhibited similar characteristics to the intact and cataractous mouse lenses with regard to the saturation transfer process.

Cellular density evaluation for malignant lymphoma using equivalent cross-relaxation rate imaging - initial experience

Objective

Equivalent cross-relaxation rate (ECR) imaging is an MRI technique used to evaluate quantitatively a change in the protein-water interaction. We aimed to evaluate retrospectively the usefulness of ECR imaging for the histologic classification of malignant lymphoma (ML).

Materials and Methods

Institutional Review Board approval was obtained and all patients provided informed consent. The study subjects included 15 patients with untreated ML who were histologically diagnosed with follicular lymphoma (FL; n = 8) or diffuse large B-cell lymphoma (DLBCL; n = 7). All patients underwent ECR imaging and the offset frequency was set at 7 ppm.

Results

The median ECR values were 71% (range; 60.7 to 75.5) in FL and 54% (50.8 to 59.4) in DLBCL (p = 0.001). The median cellular density was 1.5 ± 0.17 × 10⁶ / mm² in FL and 1.0 ± 0.70 × 10⁶ / mm² in DLBCL (p = 0.001). The correlation coefficient between the ECR values and cellular density in ML was 0.88 (p = 0.001). In FL and DLBCL, assuming ECR value cut-off points of 60%, both sensitivity and specificity were 100%.

Conclusion

A strong correlation between ECR and cellular density in ML is demonstrated and the ECR may be a useful technique to differentiate between FL and DLBCL.