Equivalent cross-relaxation rate imaging in the synthetic copolymer gels and invasive ductal carcinomas of the breast

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.

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 intermolecular cross-relaxation studies of human hemoglobin in red blood cells and bovine serum albumin in solution

Intermolecular cross-relaxation rate (CR) spectra [1/T(IS) (HDO) or 1/T(IS) (H(2) O) vs f(2) (ppm) profiles] for bovine serum albumin [BSA; molecular weight (MW), 66 kDa] solution, partially hydrolyzed BSA gel (BSA*gel) and packed human red blood cells (RBCs) with normal or unstable hemoglobin (Hb; MW, 65 kDa) were studied using f(2) irradiation ranging from - 100 to 100 ppm at γH(2) /2π of 250 Hz. The CR spectra for BSA*gel (pD 4.01, 0.10 M NaCl, 4.83 and 14.39%) exhibited different features in the off-resonance region (below - 2.00 and above 12.0 ppm) relative to that for BSA solution (pD 7.14, 0.10 M NaCl, 14.39%), indicating the association of BSA* molecules in the gel state. The CR spectrum for packed RBCs was compared with those for BSA*gel and BSA solution (14.39%) by correcting for differences in protein concentration. The corrected CR spectrum for packed normal RBCs in the off-resonance region was similar to that for BSA solution, indicating that the physical characteristics of Hb in normal RBCs may be in a solution-like state. Our results on normal RBCs were approximately consistent with the previously reported thermodynamic and hydrodynamic findings that Hb in RBCs and/or in concentrated solution seems to be in a suspension of hard scaled particles.

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.

Changes in water content of intervertebral discs and paravertebral muscles before and after bed rest

BACKGROUND

Although low back pain can be principally produced or increased during action, it may also be induced or enhanced in the morning after bed rest. During bed rest, tissue edema (increased water content) may occur. In this study, we measured the changes in water content in the intervertebral disc and the paravertebral muscle before and after bed rest using a magnetization transfer magnetic resonance imaging (MT-MRI) technique that permits measuring water content in tissues.

METHODS

A total of 20 student volunteers were enrolled in this study. MT-MRI evaluation was performed before and after bed rest. To measure water content in the intervertebral disc and paravertebral muscle, two MRI sequences were performed using MT pulse-off and MT pulse-on. Based on the two images obtained, the equivalent cross-relaxation rate (ECR) was calculated.

RESULTS

The ECR for intervertebral discs was significantly lower after bed rest than before bed rest (P < 0.01). The ECR for paravertebral equivalent cross-relaxation rate muscles was significantly higher after bed rest than before bed rest (P < 0.05).

CONCLUSION

We obtained results indicating that after bed rest the water content in the intervertebral disc and the paravertebral muscle was increased and decreased, respectively.

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

PURPOSE

To determine whether equivalent cross-relaxation rate (ECR) imaging (ECRI) is a feasible method for optimization of axillary lymph node dissection (ALND) and thereby improve quality-of-life (QOL).

MATERIALS AND METHODS

A total of 50 breast cancer patients underwent ECRI, with off-resonance saturation pulse at frequency offset of 5 ppm. ECR threshold values were determined to evaluate metastases to lymph nodes in the ALND group before examining the relationship between ECR value and cellular density. Metastases to lymph nodes of the sentinel lymph node biopsy (SLNB) group were evaluated based on the results of the ALND group.

RESULTS

In the ALND group, regions without metastases showed a higher cellular density and ECR value than those with metastases. The relationship of ECR value to cellular density formed two clusters according to the presence or absence of metastasis; cellular density was related to ECR value for both clusters. In the SLNB group, supposing a threshold ECR value of 80%, sensitivity and specificity were 88.2% and 100%, respectively.

CONCLUSION

ECRI is a potentially useful method for cellular density imaging of axillary lymph nodes. ECRI provides active information that enables ALND to be avoided, thus improving QOL.

Equivalent cross-relaxation rate imaging for sentinel lymph node biopsy in breast carcinoma

Sentinel lymph node biopsy (SLNB) is an important technique for detecting axillary lymph node metastasis in breast carcinoma patients. However, false-negative results are a problem. Equivalent cross-relaxation rate (ECR) imaging (ECRI) is a measurement method that can be used to quantitatively evaluate a change in the structural organization of lymph nodes by magnetic resonance imaging (MRI). We performed axillary ECRI in an attempt to decrease the false-negative results of SLNB. Regions without metastases showed a higher ECR value. On the other hand, regions with metastases showed a lower ECR value. The ECR images were compared with macroscopic histology images in which the presence or absence of axillary lymph node metastasis could be evaluated. ECRI is a potentially useful method for evaluating the efficacy of SLNB.

Equivalent cross-relaxation rate imaging of breast cancer

PURPOSE

To determine whether equivalent cross-relaxation rate (ECR) imaging is a feasible method for demonstrating breast cancer.

MATERIALS AND METHODS

Fifteen breast cancer patients underwent both ECR imaging, with off-resonance saturation pulses at frequency offsets of 7 and 19 ppm (ECR-7 and ECR-19, respectively) from water resonance, and gadolinium (Gd)-enhanced dynamic magnetic resonance imaging (MRI) of the breast. The mean tumor size was 26.5 mm. The tumor outlines defined by their shape and margin on ECR-7 images were compared with the subtraction images produced by the dynamic study, and the distribution of hyperintensity areas and their shapes on ECR-19 images were assessed. All patients had surgery and pathological findings were compared to ECR images.

RESULTS

The tumor outline of 13/15 (87%) tumors on ECR-7 images was nearly identical to that on subtraction images; ECR-19 images demonstrated the location and degree of fibrosis. The tumor outline of the other two tumors was less clear on ECR-7 images, and internal hyperintensity on ECR-19 images reflected intratumoral fibrotic foci. ECR-7 and -19 imaging findings allowed identification of four distinct tumor types that reflected the tumor growth patterns and their internal structures associated with fibrosis.

CONCLUSION

ECR imaging is a feasible imaging technique for demonstrating breast cancer.

Equivalent cross relaxation rate image for decreasing a false negative case of sentinel lymph node biopsy

In the breast carcinamas, sentinel lymph node biopsy (SLNB) attracts attention as technique to be settled by axillary lymph node metastasis, but existence of a false negative case is a problem. Equivalent cross relaxation rate image (ECRI) is the measurement method that we can evaluate a change of organization structure quantitatively by magnetic resonance imaging. We executed axillary ECRI as a purpose with decreasing a false negative case of SLNB. ECRI related to a macroscopic image, and it was possible to evaluate yes or no of axillary lymph node metastasis. ECRI is the useful method to evaluate adaptability of SLNB.