Advanced imaging techniques, including diffusion tensor imaging (DTI), perfusion-weighted imaging (PWI), and magnetic resonance spectroscopy (MRS) can provide more information than that regarding anatomy. These techniques have been commonly used in the clinical field and recently been shown useful in diagnosing brain tumors, especially in cases difficult to specify using conventional imaging. Differentiation requires more than attention to each advanced image. Diagnostic accuracy improves by combining information from MRS with that from other sequences, such as maps of apparent diffusion coefficient (ADC) and fractional anisotropy (FA) generated from DTI and of cerebral blood volume (CBV) generated from PWI.
We show clinical applications of advanced imaging techniques, combined MRS, for brain tumor.

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Purpose: We used magnetic resonance (MR) imaging and ultrasonography in combination with a dynamometer to assess physiological and functional aspects of the skeletal muscles after strenuous exercise that included eccentric contraction.
Methods: Seven male subjects (mean age, 21.7 years) performed ankle plantar flexion that included eccentric contraction and underwent diffusion-weighted MR imaging for calculation of the apparent diffusion coefficient (ADC) of the triceps surae muscles. We used ultrasonography combined with a dynamometer to measure the displacement of the myotendinous junction (MTJ) of the medial gastrocnemius and maximal isometric force during ankle plantar flexion. We also assessed the level of muscle soreness of the calf using a visual analogue scale. We measured these parameters before exercise and one, 2, 3, 5, and 8 days after exercise and examined significant changes from the pre-exercise value using repeated-measures analysis of variance with Dunnett's test for each measurement parameter.
Results: One day after exercise, we observed increased muscle soreness (P<0.001) and decreased MTJ displacement (P<0.05); isometric force generation tended to decrease, but the change was not significant. Muscle soreness peaked 2 days after exercise (P<0.001) and remained significantly increased until 5 days after exercise (P<0.005). The medial gastrocnemius exhibited increased ADC value 3 days after exercise (P<0.005), but the lateral gastrocnemius and the soleus showed no significant changes throughout this study.
Conclusion: Our findings suggest that muscle damage induced by eccentric contraction manifests as muscle soreness and dysfunction early after exercise and later increases water diffusion within damaged muscle.

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Purpose: We used blood oxygenation level-dependent magnetic resonance imaging (BOLD MRI) to measure renal oxygenation dynamics in rats injected with diuretics and evaluated diuretic effect on renal oxygenation.
Methods: We performed BOLD MRI studies in 32 rats using a 1.5-tesla MR imaging system for animal experiments. We intravenously injected rats with saline (n=7), furosemide (n=7), acetazolamide (n=6), or mannitol (n=6). For controls, 6 rats were not injected with drugs. We estimated the apparent transverse relaxation rate (R₂*) from the apparent transverse relaxation time (T₂*)-weighted images and measured the time course of R₂* at 4-min intervals over approximately 30 min.
Results: Compared with preadministration values, the R₂* value did not change significantly in either the cortex or medulla in the control and mannitol groups but decreased significantly in the saline group; the R₂* value significantly decreased in the medulla but did not change significantly in the cortex in the furosemide group; and the R₂* value significantly increased in the medulla and significantly decreased in the cortex in the acetazolamide group.
Conclusion: Our study results suggest that BOLD MRI is useful for evaluating the dynamics of renal oxygenation in response to various diuretics in the renal cortex and in the medulla.

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Purpose: In vivo, the attenuation of diffusion-weighted imaging (DWI) signal at high b-values is sometimes nonlinear when plotted with semilogarithmic function and is fit well by a biexponential function. Previous reports have indicated that the fast and slow component fractions of the apparent diffusion coefficient (ADC) can be derived by biexponential fitting and that these fractions correspond to the actual diffusion components in the extra- and intracellular space. In this study, we investigated the clinical utility of DWI for the breast by performing DWI using multiple b-factors on healthy volunteers and clinical subjects, analyzing the signal by fitting it with a biexponential equation, and comparing the fitting parameters of breast lesions.
Patients and Methods: We investigated 8 healthy women as normal cases and 80 female patients with a total of 100 breast tumors (42 benign, 58 malignant tumors) as clinical cases. We performed DWI using 12 b-values for the healthy cases and 6 b-values for the clinical cases, up to a maximum b-value of 3500 s/mm².
Results: Decay of DWI signal of normal mammary glands, most cysts, and some fibroadenomas showed a monoexponential relationship, and conversely, that of intraductal papilloma (IDP) and malignant tumors was well fitted by a biexponential function. Comparison of parameters derived from biexponential fitting demonstrated no significant difference between benign and malignant lesions. For malignant tumor subtype, the fast component fraction of noninvasive ductal carcinoma was statistically greater than that of invasive ductal carcinoma.
Conclusions: Although the parameters from biexponential fitting may reflect the character of tumor cellularity, because pathological diagnosis was performed with an emphasis on cell configuration or shape rather than cellularity, it was difficult to distinguish malignant from benign tumors, including many IDPs, or to distinguish tissue types using DWI signal attenuation alone.

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Purpose: We assessed the clinical utility of our proposed simplified method for T₁ρ mapping calculations.
Materials and Methods: Ten healthy subjects underwent scanning on a 3-tesla magnetic resonance system using an 8-channel phased-array coil. For each subject, we obtained sagittal T₁ρ-prepared images using 5 different time of spin-lock pulses (TSL=1, 20, 40, 60, and 80 ms), produced conventional T₁ρ maps (cT₁ρ maps) using all TSLs, and recomputed our proposed simplified T₁ρ maps (sT₁ρ maps) using a decreasing number of TSLs (from 4 to 2). We then investigated the differences and correlations in T₁ρ values of the tissues obtained using different numbers of spin-lock times.
Results: There was a strong positive correlation (single measure intraclass correlation coefficient=0.948; 95% confidence interval=0.911 to 0.970) in T₁ρ values of tissues between the cT₁ρ and sT₁ρ [1, 80] maps. The 2 maps were comparable, though there was a small difference in T₁ρ value between the two. The total scan time to acquire the data from 5 spin-lock times was 16 min 15 s. Similarity of the T₁ρ [1, 80] map with the conventional approach reduced scan time by 60%, to 6 min 30 s.
Conclusion: The clinical relevance of our proposed simplified method is potentially similar to that of the conventional method, and our method requires a shorter examination time and generally preserves the reliability of the T₁ρ relaxation time of the tissues.

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We assessed the usefulness and limitations of utilizing apparent diffusion coefficient (ADC) values on diffusion-weighted imaging (DWI) for the differential diagnosis of benign and malignant non-mass-like breast lesions. We retrospectively reviewed 27 such lesions (16 malignant, 11 benign) detected on magnetic resonance (MR) imaging and analyzed the enhancing patterns of dynamic contrast-enhanced DCE-MRI (distribution and internal enhancement), kinetic curve patterns, and ADC values. All images were obtained with a 1.5-tesla MR unit, with patients supine. On DCE-MRI, malignant lesions tended to show either segmental or branching-ductal distribution, and when lesions with these patterns were considered malignant, sensitivity was 68.8%; specificity, 63.6%; positive predictive value (PPV), 73.3%; negative predictive value (NPV), 58.3%; and accuracy, 66.7%. Kinetic curve analysis did not reliably differentiate benign and malignant non-mass-like lesions. There was no significant difference between the mean ADC value of the malignant lesions, 0.968×10⁻³ mm²/s at b=1000 s/mm², and that of benign lesions, 1.207×10⁻³ mm²/s (P=0.109). Receiver operating characteristic (ROC) analysis revealed the most effective threshold of ADC value for differentiating tumors as 1.1×10⁻³ mm²/s; values lower than this were observed more often in malignant than benign lesions (P=0.054). Us of this threshold yielded sensitivity of 68.8%; specificity, 72.7%; PPV, 78.6%; NPV, 61.5%; and accuracy, 70.4%. Combining the ADC value criteria with the analysis of DCE-MRI pattern increased sensitivity to 93.8%, negative predictive value (NPV) to 85.7%, and accuracy to 77.8% but decreased specificity to 54.5%. Use of ADC values does not adequately improve DCE-MRI performance for differential diagnosis of non-mass-like breast lesions, but adding the ADC value criteria to the DCE-MRI pattern analysis improves sensitivity, NPV, and accuracy.

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We incidentally detected a case of solitary plasmacytoma of the sternum by magnetic resonance (MR) imaging of the cervical spine. At detection, the patient had no symptoms, the lesion was localized in the bone marrow of the sternum, and there were no findings of bone destruction. The lesion showed high contrast on diffusion-weighted images, gradually enlarged over 3 years, and was confirmed as a solitary plasmacytoma at open biopsy 3 years after detection. Radiologists should pay attention to incidental findings in the upper part of the sternum at MR imaging examination of the cervical spine.

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A 38-year-old woman was transferred to the hospital with lower abdominal pain. Magnetic resonance (MR) imaging revealed an irregular ovarian wall with a solid component and a fluid-fluid level in the cystic mass and the pelvic space, which was thought to be pathognomonic for the rupture of an endometrioma with a malignant ovarian tumor. Histologic examination following adnexectomy revealed a ruptured endometrioma associated with endometrioid adenocarcinoma. A fluid-fluid level in the cystic mass and pelvic space may be pathognomonic MRI feature for a rupture of either an endometrioma or an endometrioma with a malignant tumor.

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Heavily T₂-weighted 3-dimensional fluid-attenuated inversion recovery (hT₂W-3D-FLAIR) technique has been reported to be more sensitive than conventional 3D-FLAIR in detecting low concentrations of gadolinium-based contrast media (GBCM) in fluid. We applied hT₂W-3D-FLAIR to visualize endolymphatic hydrops of Ménière's disease in 3 patients 4 hours after single-dose intravenous injection of GBCM and successfully visualized endolymphatic hydrops in either the cochlea or vestibule in all patients. This technique can be implemented in a clinical setting.

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