A case of a blind-ending right ureter first identified intraoperatively during total laparoscopic hysterectomy for uterine adenomyosis and fibroids in a woman with severe ipsilateral kidney hypoplasia.

Detecting ureteral injury-a serious intraoperative and postoperative complication of hysterectomy-is a high level of difficulty if ureteral malformations are not identified preoperatively. A 39-year-old Japanese woman underwent total laparoscopic hysterectomy for uterine adenomyosis. During surgery, ureteral peristalsis was absent on the right side, whereas the left ureter was visible under the peritoneum. Transabdominal ultrasonography failed to locate the right kidney, with cystoscopy showing no flow from the right ureteral orifice. The ureteral tunnel was identified by tracing the vascular path of the internal iliac and uterine arteries, confirming that the corded tissue was the right ureter. Postoperative contrast-enhanced CT revealed severe right kidney atrophy with no contrast effect or connected ureter. Based on intraoperative laparoscopy and postoperative examination, a diagnosis of a unilateral ureteral scar with a proximal blind end and ipsilateral renal dysgenesis was established, marking the first reported instance of endoscopic visualization of this anomaly. In addition to normal pelvic anatomy, surgeons must consider embryological abnormalities to prevent intraoperative complications.

Combined histological and DNA methylome profiling approaches may provide insights into the pathophysiology of ovarian endometriomas.

Purpose: To test the theory that invaginated ovarian surface epithelium and endometrial implants on the ovary form ovarian endometriomas. Methods: Adhesion sites of ovarian endometrioma on the peritoneum and consecutive ovarian endometrioma cyst wall, called non-adhesion sites, were histologically examined. DNA methylomes of the adhesion sites, non-adhesion sites, and blueberry spots were compared with those of ovary, endometrium, and peritoneum. Results: The non-adhesion sites showed an ovarian surface epithelium-like structure near the adhesion site, which continued to a columnar epithelium-like structure. Calretinin staining was strong in the ovarian surface epithelium-like structure but weak in the columnar epithelium-like structure. Estrogen receptors were absent in the ovarian surface epithelium-like structure, but present in the columnar epithelium-like structure. The adhesion sites had endometrial gland-like structures that expressed estrogen receptors. Analyses of DNA methylomes classified the non-adhesion sites and ovaries into the same group, suggesting that ovarian endometriomas originate from the ovarian surface epithelium. The adhesion sites, blueberry spots and peritoneum were classified in the same group, suggesting that the adhesion sites and blueberry spots originate from the peritoneum. Conclusions: The present results support the invagination theory. Ovarian endometriomas consist of invaginated ovarian surface epithelium with celomic metaplasia and endometrium implants on the peritoneum.

The necessity of gait evaluation on the 7th day after tap tests for the idiopathic normal pressure hydrocephalus patients.

BACKGROUND: A tap test is established as an evaluation method to indicate shunt surgery for hydrocephalus, especially idiopathic normal pressure hydrocephalus (iNPH). The timing of gait assessment after the test is still controversial, while some studies reported the effectiveness of the gait evaluation up to 2nd day after tap tests. Our study explored whether the gait evaluation on the 7th day after a tap test is necessary. METHODS: We retrospectively evaluated 129 consecutive cases with possible iNPH who performed gait assessment on all 1st, 3rd, and 7th days after tap tests between May 2020 and February 2022. We reviewed the following items of the patients: age, sex, modified Rankin scale, iNPH grading scale, Mini-Mental State Evaluation (MMSE), and neurological imaging. The number of probable iNPH patients who improved their gait each day after the test was analyzed. We also assessed the number of definite iNPH patients and revealed the background characteristics of the patients who showed gait improvement on the 7th day after the tests. RESULTS: Of the 129 patients who met our inclusion criteria, 57 were judged as probable iNPH on the 1st day, 28 were new on the 3rd, and 23 were new on the 7th. The number of probable iNPH patients up to the 7th day after tests was significantly more extensive than that of those up to the 3rd (108 [83.7%] vs. 85 [65.9%]; 95% confidence interval [CI], p < 0.0001). The number of definite iNPH patients was also significantly more prominent when the evaluation after the tests was performed on all of the 1st, the 3rd, and the 7th days than just on the 1st (72 vs. 42; 95% CI, p = 0.00016) or both of the 1st and the 3rd (72 vs. 61; 95% CI, p = 0.00074). No statistically significant difference existed in the patients' backgrounds except for the pre-tap test MMSE. CONCLUSION: Gait evaluation on the 7th day after tap tests, in addition to the first few days, may reduce the number of iNPH patients who miss the opportunity of getting beneficial treatment.

Vascular Malformations and Tumors: A Review of Classification and Imaging Features for Cardiothoracic Radiologists.

The International Society for the Study of Vascular Anomalies (ISSVA) classification is a comprehensive histology-based scheme that was updated in 2018. It is important for cardiothoracic imagers to understand this classification to ensure that accurate terminology is used and that archaic terms are avoided when vascular lesions are described. Knowledge of the various malformations (including common conditions, such as venous malformation, arteriovenous fistula, and arteriovenous malformation) and vascular tumors allows for timely diagnosis and appropriate management. This review describes various vascular anomalies, in accordance with ISSVA classification and terminology; highlights key imaging features associated with each; and discusses the role of different imaging modalities. Keywords: Pulmonary, Soft Tissues/Skin, Vascular, Arteriovenous Malformation © RSNA, 2023.

The role of MRI in the prognosis of Wernicke's encephalopathy.

BACKGROUND AND PURPOSE: Wernicke's encephalopathy (WE) is a severe acute disorder related to thiamine deficiency. This study was aimed at revealing the relationship between clinical and imaging findings and WE recovery. METHODS: We retrospectively reviewed 34 cases of WE diagnosed between 2003 and 2020 (median age: 57 years, 14 females) at two academic institutions. WE cases were divided into two groups with symptomatic recovery within 4 weeks (group 1) or later (group 2). The lesion sites were divided into typical and atypical sites (total sites defined as when either typical or atypical sites were involved). Clinical and MRI features were compared between them as appropriate. RESULTS: WE patients were divided into group 1 (19 cases, median age: 57 years, 10 females) and group 2 (15 cases, median age: 57 years, four females). Regarding clinical features, only cerebellar ataxia was more often observed in group 1 than in group 2. Regarding MRI features, signal abnormality on T2-weighted image (WI)/fluid-attenuated inversion recovery (FLAIR) was more often observed in atypical sites between groups 1 and 2 (1/19 vs. 7/15; p = .01). There were significant differences between groups 1 and 2 regarding the presence of both vasogenic edema and cytotoxic edema in total sites (4/11 vs. 11/15, p = .005; 1/19 vs. 6/15, p = .03), with a significant difference in the presence of vasogenic edema in typical sites (4/19 vs. 10/15, p = .01). CONCLUSION: The early recovered group showed a lower incidence of T2WI/FLAIR abnormality in atypical sites and diffusion signal abnormality in total or typical sites with a lower incidence of cerebellar ataxia.

Imaging Features of Ectopic Tissues and Their Complications: Embryologic and Anatomic Approach.

Ectopic tissue is an anatomic abnormality in which tissue develops in an area outside its normal location. It is primarily caused by abnormalities during the process of embryologic development. Although the majority of individuals with ectopic tissues remain asymptomatic, various symptoms and associated complications can occur. Failure in normal embryologic development leads to loss of normal physiologic function or may result in harmful functions such as ectopic hormonal secretion in the ectopic pituitary adenoma. Ectopic tissues may also frequently mimic tumors. For example, developmental abnormalities in the pharyngeal pouches may result in an ectopic parathyroid gland and ectopic thymus, both of which are frequently misdiagnosed as tumors. Adequate knowledge of embryology is essential for understanding the differential diagnoses of ectopic tissues and facilitating appropriate management. The authors summarize the embryologic development and pathogenesis of ectopic tissues by using illustrations to facilitate a deeper understanding of embryologic development and anatomy. Characteristic imaging findings (US, CT, MRI, and scintigraphy) are described for ectopic tissues of the brain, head, neck, thorax, abdomen, and pelvis by focusing on common conditions that radiologists may encounter in daily practice and their differential diagnoses. ©RSNA, 2023 Quiz questions for this article are available through the Online Learning Center.

Neuroimaging of hypophysitis: etiologies and imaging mimics.

Hypophysitis is an inflammatory disease affecting the pituitary gland. Hypophysitis can be classified into multiple types depending on the mechanisms (primary or secondary), histology (lymphocytic, granulomatous, xanthomatous, plasmacytic/IgG4 related, necrotizing, or mixed), and anatomy (adenohypophysitis, infundibulo-neurohypophysitis, or panhypophysitis). An appropriate diagnosis is vital for managing these potentially life-threatening conditions. However, physiological morphological alterations, remnants, and neoplastic and non-neoplastic lesions may masquerade as hypophysitis, both clinically and radiologically. Neuroimaging, as well as imaging findings of other sites of the body, plays a pivotal role in diagnosis. In this article, we will review the types of hypophysitis and summarize clinical and imaging features of both hypophysitis and its mimickers.

Advanced imaging of head and neck infections.

When head and neck infection is suspected, appropriate imaging contributes to treatment decisions and prognosis. While contrast-enhanced CT is the standard imaging modality for evaluating head and neck infections, MRI can better characterize the skull base, intracranial involvement, and osteomyelitis, implying that these are complementary techniques for a comprehensive assessment. Both CT and MRI are useful in the evaluation of abscesses and thrombophlebitis, while MRI is especially useful in the evaluation of intracranial inflammatory spread/abscess formation, differentiation of abscess from other conditions, evaluation of the presence and activity of inflammation and osteomyelitis, evaluation of mastoid extension in middle ear cholesteatoma, and evaluation of facial neuritis and labyrinthitis. Apparent diffusion coefficient derived from diffusion-weighted imaging is useful for differential diagnosis and treatment response of head and neck infections in various anatomical sites. Dynamic contrast-enhanced MRI perfusion may be useful in assessing the activity of skull base osteomyelitis. MR bone imaging may be of additional value in evaluating bony structures of the skull base and jaw. Dual-energy CT is helpful in reducing metal artifacts, evaluating deep neck abscess, and detecting salivary stones. Subtraction CT techniques are used to detect progressive bone-destructive changes and to reduce dental amalgam artifacts. This article provides a region-based approach to the imaging evaluation of head and neck infections, using both conventional and advanced imaging techniques.

Utility of dynamic susceptibility contrast MRI for differentiation between paragangliomas and meningiomas in the cerebellopontine angle and jugular foramen region.

PURPOSE: Differentiation of paragangliomas and meningiomas can be a challenge. This study aimed to assess the utility of dynamic susceptibility contrast perfusion MRI (DSC-MRI) to distinguish paragangliomas from meningiomas. METHODS: This retrospective study included 40 patients with paragangliomas and meningiomas in the cerebellopontine angle and jugular foramen region between March 2015 and February 2022 in a single institution. Pretreatment DSC-MRI and conventional MRI were performed in all cases. Normalized relative cerebral blood volume (nrCBV), relative cerebral blood flow (nrCBF), relative mean transit time (nrMTT), and time to peak (nTTP) as well as conventional MRI features were compared between the 2 tumor types and between meningioma subtypes as appropriate. Receiver operating characteristic curve and multivariate logistic regression analysis were performed. RESULTS: Twenty-eight meningiomas including 8 WHO grade II meningiomas (12 males, 16 females; median age 55 years) and 12 paragangliomas (5 males, 7 females; median age 35 years) were included in this study. Paragangliomas had a higher rate of cystic/necrotic changes (10/12 vs 10/28; P = 0.014), a higher rate of internal flow voids (9/12 vs 8/28; P = 0.013), higher nrCBV (median 9.78 vs 6.64; P = 0.04), and shorter nTTP (median 0.78 vs 1.06; P < 0.001) than meningiomas. There was no difference in conventional imaging features and DSC-MRI parameters between meningioma subtypes. nTTP was identified as the most significant parameter for the 2 tumor types in the multivariate logistic regression analysis (P = 0.009). CONCLUSIONS: In this small retrospective study, DSC-MRI perfusion differences were observed between paragangliomas and meningiomas, but not between grade I and II meningiomas.

Precise differentiation between jugular foramen paragangliomas and metastases: utility of diffusion-weighted and dynamic contrast-enhanced magnetic resonance imaging.

PURPOSE: This study tested the utility of diffusion-weighted imaging (DWI) and dynamic contrast-enhanced imaging (DCE-MRI) in differentiating paragangliomas and metastases in the jugular foramen in combination with conventional imaging. METHODS: Forty-nine consecutive patients with paragangliomas or metastases between January 2015 and April 2022 were included in this retrospective study. All patients had pretreatment DWI and DCE-MRI. Between paragangliomas and metastases, normalized apparent diffusion coefficient (nADCmean) and DCE-MRI parameters were compared along with conventional imaging features (enhancement pattern, presence of flow voids, cystic/necrotic change, and bone erosion). The diagnostic performance was tested using receiver operating characteristic (ROC) analysis. RESULTS: Thirty-five paragangliomas (5 male; median 49 years) and 14 metastases (9 male; median 61 years) were analyzed. The most common 3 primary cancers included 4 lung cancers, 3 breast cancers, and 3 melanomas. The presence of flow void was significantly different between paragangliomas and metastases (21/35 vs 2/14; P = 0.0047) in conventional imaging features, while fractional plasma volume (Vp) was significantly different between the two tumor types (median 0.46 vs 0.19; P < 0.001) in DWI and DCE-MRI parameters. The areas under the ROC curves (AUCs) of the presence of flow void and Vp were 0.72 and 0.93, respectively. The AUC of the combination of the presence of flow void and Vp was 0.95 and significantly improved compared to that of the presence of flow void (P < 0.001). CONCLUSION: Adding DCE-MRI to the head and neck protocol can aid in the precise differentiation between jugular foramen paragangliomas and metastases.

Human Immunodeficiency Virus: Opportunistic Infections and Beyond.

Human immunodeficiency virus (HIV) infection causes substantial morbidity and mortality worldwide. Although antiretroviral therapy (ART) has changed the epidemiology of HIV in the last 20 years with increased survival and decreasing incidence of opportunistic infections (OI), CNS OI remain a major cause of morbidity. Improved survival has also increased neurological presentations due to co morbid conditions, treatment related side effects and inflammatory syndromes. Being familiar with the imaging findings, the impact of ART and interpretation of imaging in the context of clinical and laboratory findings is important for radiologists as well as clinicians in the management of HIV-infected patients.

Laparoscopic Adenomyomectomy under Real-Time Intraoperative Ultrasound Elastography Guidance: A Case Series and Feasibility Study.

BACKGROUND: This study aimed to examine the clinical characteristics of 11 patients undergoing laparoscopic adenomyomectomy guided by intraoperative ultrasound elastography and this technique's feasibility. PATIENTS AND METHODS: Eleven patients undergoing laparoscopic adenomyomectomy using ultrasound elastography for adenomyosis at Kawasaki Medical School Hospital in Okayama, Japan between March 2020 and February 2021 were enrolled. Operative outcomes included operative time, operative bleeding, resected weight, operation complications, percent change in hemoglobin (Hb) values, and uterine volume pre- and postoperatively. Dysmenorrhea improvement was evaluated by changes in visual analog scale (VAS) scores pre- and 6- and 12-months postoperatively. RESULTS: The median operative time and bleeding volume was 125 min (range, 88-188 min) and 150 mL (10-450 mL), respectively. The median resected weight was 5.0 g (1.5-180 g). No intraoperative or postoperative blood transfusions or perioperative complications were observed. The median changes in uterine volume, Hb value, and VAS score were -49% (-65 to -28%), -3% (-11 to 35%), and -80% (-100 to -50%), respectively. The median follow-up period post-surgery was 14 months (7-30 months). Adenomyosis recurrence was not observed in the patients during the follow-up period. CONCLUSIONS: Laparoscopic adenomyomectomy using ultrasound elastography guidance is minimally invasive and resects as many adenomyotic lesions as possible.

TRACP-5b/BAP Score After 3 Months of Treatment With Combined SERM/E2 Therapy Can Predict Changes in Lumbar Spine Bone Mineral Density After 1 Year of Treatment in Early Postmenopausal Osteopenia.

Although changes in bone mineral density (BMD) are important indexes in osteoporosis treatment, no markers are available to predict them. Given the importance of assessing the therapeutic windows of antiresorptives, we explored potential biomarkers of bone remodeling in patients receiving treatment for osteopenia. Postmenopausal women with osteopenia (defined as a lumbar BMD T-score <-1.0 standard deviation (SD) below that of a reference population but >-2.5 SD) were administered estradiol 1 mg/d and bazedoxifene 20 mg/d. After 3 months of treatment, we evaluated their ratio of serum bone-specific tartrate-resistant acid phosphatase to bone-specific alkaline phosphatase (TRACP-5b/BAP), which is widely used for evaluating bone turnover in postmenopausal patients with osteoporosis in Japan because their minimum significant changes are smaller than other bone turnover markers such as carboxy-terminal collagen cross-links (CTX) or N-terminal propeptide of type I procollagen (P1NP) and thus, accurately reflect bone turnover. After 1 year of treatment, we assessed changes in lumbar BMD. The cut-off TRACP-5b/BAP scores for a ≤-2% decrease and ≥2% increase in lumbar spine BMD were 38.4 and 29.0, respectively. The TRACP-5b/BAP scores were associated with significantly greater areas under the curve than the other evaluated parameters. These results suggest that the TRACP-5b/BAP score after 3 months of osteopenia treatment can predict changes in lumbar BMD after 1 year of treatment. Moreover, a receiver operating characteristic curve analysis of TRACP-5b/BAP scores after 3 months of antiresorptive therapy and percent changes in BMD at 1 year revealed that the TRACP-5b/BAP score, as an index of the balance between bone resorption and formation markers, has the potential to serve as a modulator of the anabolic window reflective of bone remodeling. This study's findings also suggested a role for TRACP-5b/BAP score as a predictor of a non-response to antiresorptive therapy, thus offering health economic implications for osteoporosis treatment. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Perfusion and diffusion-weighted imaging parameters: Comparison between pre- and postbiopsy MRI for high-grade glioma.

We aimed to evaluate the differences in dynamic susceptibility contrast (DSC)- magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) parameters between the pre- and postbiopsy MRI obtained before treatment in patients with diffuse midline glioma, H3K27-altered. The data of 25 patients with pathologically proven diffuse midline glioma, H3K27-altered, were extracted from our hospital's database between January 2017 and August 2021. Twenty (median age, 13 years; range, 3-52 years; 12 women) and 8 (13.5 years; 5-68 years; 1 woman) patients underwent preoperative DSC-MRI and DWI before and after biopsy, respectively. The normalized corrected relative cerebral blood volume (ncrCBV), normalized relative cerebral blood flow (nrCBF), and normalized maximum, mean, and minimum apparent diffusion coefficient (ADC) were calculated using the volumes-of-interest of the tumor and normal-appearing reference region. The macroscopic postbiopsy changes (i.e., biopsy tract, tissue defect, and hemorrhage) were meticulously excluded from the postbiopsy measurements. The DSC-MRI and DWI parameters of the pre- and postbiopsy groups were compared using the Mann-Whitney U test. The ncrCBV was significantly lower in the postbiopsy group than in the prebiopsy group [prebiopsy group: median 1.293 (range, 0.513 to 2.547) versus postbiopsy group: 0.877 (0.748 to 1.205), P = .016]. No significant difference was observed in the nrCBF and normalized ADC values, although the median nrCBF was lower in the postbiopsy group. The DSC-MRI parameters differed between the pre- and postbiopsy MRI obtained pretreatment, although the macroscopic postbiopsy changes were carefully excluded from the analysis. The results emphasize the potential danger of integrating and analyzing DSC-MRI parameters derived from pre- and postbiopsy MRI.

Relationships between contrast-enhanced computed tomography features of hard palate cancer and pathological depth of invasion.

OBJECTIVE: The study aimed to determine the relationships between contrast-enhanced computed tomography (CECT) features of hard palate cancer (radiological depth of invasion [r-DOI], detectability of the lesion, and tumor invasion into the palatal bone) and the pathological DOI (p-DOI) of the tumors. STUDY DESIGN: In total, 36 lesions were retrospectively evaluated by 2 board-certified radiologists, who examined CECT scans for the radiological features, and 2 board-certified pathologists, who measured the p-DOI on histopathologic sections. Correlation between r-DOI and p-DOI was calculated. The Youden index was used to calculate the optimal p-DOI cutoff values to distinguish between detectable and undetectable lesions and between tumors with and without bony structure invasion. RESULTS: There was excellent agreement between r-DOI and p-DOI (intraclass correlation coefficient = 0.80). The p-DOI of CECT-detectable lesions was significantly greater than that of CECT-undetectable lesions (P < .001), with a p-DOI cutoff value of 4 mm. The p-DOI of lesions that had invaded the palatal bone was significantly larger than that of lesions without invasion (P = .039), with a p-DOI cutoff value of 7 mm. CONCLUSION: Radiological DOI, tumor detectability, and invasion into the palatal bone can be useful in planning surgical treatment strategies for hard palate cancer.

Radiological features of human papillomavirus-related multiphenotypic sinonasal carcinoma: systematic review and case series.

PURPOSE: To comprehensively summarize the radiological characteristics of human papillomavirus (HPV)-related multiphenotypic sinonasal carcinomas (HMSCs). METHODS: We reviewed the findings for patients with HMSCs who underwent computed tomography (CT) and/or magnetic resonance imaging (MRI) and included nine cases from nine publications that were identified through a systematic review and three cases from our institution. Two board-certified radiologists reviewed and evaluated the radiological images. RESULTS: The locations in almost all cases included the nasal cavity (11/12, 91.7%). The involved paranasal sinuses included the ethmoid sinus (6/12, 50.0%) and maxillary sinus (3/12, 25.0%). The mean long diameter of the tumors was 46.3 mm. The margins in 91.7% (11/12) of the cases were well-defined and smooth. Heterogeneous enhancement on contrast-enhanced CT, heterogeneous high signal intensities on T2-weighted images and heterogeneous enhancement on gadolinium-enhanced T1-weighted images were noted in 2/2, 5/5, and 8/8 cases, respectively. Mean apparent diffusion coefficient values in two cases of our institution were 1.17 and 1.09 × 10-3 mm2/s. Compressive changes in the surrounding structures were common (75%, 9/12). Few cases showed intraorbital or intracranial extension. None of the cases showed a perineural spread, neck lymph node metastasis, or remote lesions. CONCLUSIONS: We summarized the CT and MRI findings of HMSCs. Knowledge of such characteristics is expected to facilitate prompt diagnosis and appropriate management.

Advanced MRI to differentiate schwannomas and metastases in the cerebellopontine angle/internal auditory canal.

BACKGROUND AND PURPOSE: Differentiating schwannomas and metastases in the cerebellopontine angles (CPA)/internal auditory canals (IAC) can be challenging. This study aimed to assess the role of diffusion-weighted imaging (DWI) and dynamic contrast-enhanced MRI (DCE-MRI) to differentiate schwannomas and metastases in the CPA/IAC. METHODS: We retrospectively reviewed 368 patients who were diagnosed with schwannomas or metastases in the CPA/IAC between April 2017 and February 2022 in a single academic center. Forty-three patients had pretreatment DWI and DCE-MRI along with conventional MRI. Normalized mean apparent diffusion coefficient ratio (nADCmean) and DCE-MRI parameters of fractional plasma volume (Vp), flux rate constant (Kep), and forward volume transfer constant were compared along with patients' demographics and conventional imaging features between schwannomas and metastases as appropriate. The diagnostic performances and multivariate logistic regression analysis were performed using the significantly different values. RESULTS: Between 23 schwannomas (15 males; median 48 years) and 20 metastases (9 males; median 61 years), nADCmean (median: 1.69 vs. 1.43; p = .002), Vp (median: 0.05 vs. 0.20; p < .001), and Kep (median: 0.41 vs. 0.81 minute-1 ; p < .001) were significantly different. The diagnostic performances of nADCmean, Vp, and Kep were 0.77, 0.90, and 0.83 area under the curves, with cutoff values of 1.68, 0.12, and 0.53, respectively. Vp was identified as the most significant parameter for the tumor differentiation in the multivariate logistic regression analysis (p < .001). CONCLUSIONS: DWI and DCE-MRI can help differentiate CPA/IAC schwannomas and metastases, and Vp is the most significant parameter.

Imaging of Normal Brain Aging.

Understanding normal brain aging physiology is essential to improving healthy human longevity, differentiation, and early detection of diseases, such as neurodegenerative diseases, which are an enormous social and economic burden. Functional decline, such as reduced physical activity and cognitive abilities, is typically associated with brain aging. The authors summarize the aging brain mechanism and effects of aging on the brain observed by brain structural MR imaging and advanced neuroimaging techniques, such as diffusion tensor imaging and functional MR imaging.