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OBJECTIVE: In our multi center trial we compared the potentials of biphasic contrast-enhanced computed tomography (CT) and a novel tissue-specific magnetic resonance imaging (MRI) contrast agent gadoxetic acid disodium in liver lesion characterization. METHODS: A total of 176 patients with 252 liver lesions were analyzed. There were 104 malignant and 148 benign lesions. High-field strength (1.0 T or 1.5 T) MR systems with T1-and T2-weighted sequences were used with and without fat suppression. After gadoxetic acid disodium injection, dynamic imaging and hepatocyte phase MR imaging were performed. Biphasic with 150 mg I/kg of body weight (100-200 mL) spiral CT was also performed. Image reading consisted of on-site (by study investigators) and fully blinded off-site (by E.S.P; C.R; and A.S) evaluations. The classification (benign or malignant) and characterization (lesion type) outcomes of both techniques were assessed. All imaging results were verified against a standard of reference. RESULTS: Both on-site and off-site evaluations demonstrated increases in the lesion classification accuracy with gadoxetic acid disodium-enhanced MRI when compared with spiral CT. This improvement was also shown for characterization. Gadoxetic acid disodium was well tolerated. CONCLUSIONS: Gadoxetic acid disodium offers a safe and diagnostically powerful tool for the evaluation of patients with focal liver lesions with a reliable assessment of lesion classification and characterization.

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BACKGROUND: Vaginal anatomy has been poorly studied. This study aimed to measure baseline dimensions of the undistended vagina of women of reproductive age. METHODS: We combined baseline information collected from five clinical trials using magnetic resonance imaging (MRI) to quantify distribution of a vaginal gel. Seventy-seven MRI scans were performed on 28 women before gel application to establish baseline vaginal measurements. Average dimensions were calculated for each woman and for the population. The influence of potential covariates (age, height, weight and parity) on these dimensions was assessed. RESULTS: MRI measurements are reproducible. The SD surrounding the mean at each anatomical site, and with summary measurements, was significantly smaller with each subject compared with the population. Mean vaginal length from cervix to introitus was 62.7 mm. Vaginal width was largest in the proximal vagina (32.5 mm), decreased as it passed through the pelvic diaphragm (27.8 mm) and smallest at the introitus (26.2 mm). Significant positive associations were parity with vaginal fornix length, age with pelvic flexure width and the height with width at the pelvic flexure. CONCLUSION: No one description characterized the shape of the human vagina. Although there is variation among women, variables such as parity, age and height are positively associated with differences in baseline dimensions.

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OBJECTIVE: The objective of this study was to systematically review the use of MRI for the evaluation of deployment characteristics of vaginal microbicides and to understand the relationship of gel spread with potential influencing factors. METHODS: Data from four clinical trials that used MRI to assess the deployment of a vaginal gel were combined. A linear mixed model best represented the spread of gel over time. Significant covariates that influence vaginal gel spread are baseline dimensions of the vagina, time from insertion, gel type, ambulation and volume of gel. RESULTS: These data demonstrate that MRI has outstanding intraperson validity and reproducibility. Therefore, paired design, using linear modeling adjusting for significant covariates, is the most efficient study design for comparison of products or volumes. Division of the vagina into two distinct anatomical regions best explains difference in gel spread, i.e., upper area (above the pelvic diaphragm) and lower area (below pelvic diaphragm). CONCLUSION: We conclude that the concept of spread from the cervix to the introits, in one dimension, is inadequate to explain spread of gel due to the complex shape of the vagina.

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NuvaRing, a combined contraceptive vaginal ring 54 mm in diameter, offers many advantages over oral contraceptives. To better delineate in vivo placement, we performed MRI to confirm its anatomical position. Two healthy users, one nulliparous and one parous, underwent a series of MRI: preinsertion, immediately postinsertion and after ambulation. Three-dimensional imaging of the human vagina demonstrates that in vivo, NuvaRing is located superior to the urogenital diaphragm (UGD), surrounding the cervix. The superior-most aspect of the ring lies behind (posterior) the cervix, at a level superior to the external os. The inferior aspect of the ring also lies in the vaginal canal above the UGD. The entire cervix rests inside the ring. The preambulation image in the nulliparous woman was the only exception. In this case, the upper portion of the ring was at the level of the lower-mid cervix and the lower aspect below the UGD. After ambulation, the ring moved cephalad and surrounded the cervix. In all instances, ambulation resulted in lower aspect of NuvaRing moving away from the introitus. In vivo, NuvaRing is compressed laterally forming a gentle oval in the anterior-posterior direction (5-7 mm longer than wide), an effect that is seen more in nulliparous women.

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This was a blinded crossover study to determine the in vivo distribution of 2.5 and 3.5 mL of 6% cellulose sulfate gel. This potential vaginal microbicide was mixed with dilute gadolinium chelate and inserted into the vagina. Magnetic resonance imaging was performed at baseline and repeated after 5, 20, 35 and 50 min with subjects either resting or ambulating between data acquisitions. Use of 2.5 mL with no ambulation gave low linear spread (53.1% of vaginal length) and surface contact (61.7%) at 50 min. Using 3.5 mL of gel with ambulation improved linear spread (84.5%) and surface contact (85.9%) of the gel in the same time interval without significant leakage. Most linear spreading took place in the first 5 min after insertion, although lateral spreading continued to increase with time especially when ambulation took place. Leakage and gel was not a significant problem at either volume.

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C31G (Savvy) has been developed as a topical vaginal microbicide with broad-spectrum antibacterial and antiviral properties. The objective of this study was to evaluate the distribution of a 1.0% concentration of (3.5 mL) C31G vaginal gel in the human pelvis using magnetic resonance imaging (MRI). Gel delivery with a standard applicator was primarily to the upper vagina and was well tolerated. Vaginal mucosal coverage at 18 min was excellent with 92% linear coverage and 75% surface contact coverage of the vagina. The upper vagina was almost completely covered and gel was also noted in the lower vagina. Coverage 6 h after application was substantially decreased, with 60% of maximal linear coverage and 41% surface contact. There was a very minimal coverage of the vaginal mucosa noted 24 h following insertion. Simulated intercourse resulted in relatively little change in overall distribution at all three time points. Repeat application of the gel may be necessary if intercourse has not occurred within the first few hours after initial insertion.

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RATIONALE AND OBJECTIVE: Postgraduate training programs in radiology exist in several African nations. The ability of these programs to train radiologists is necessarily affected by local availability of educational resources, including clinical case volume, radiology equipment and maintenance, number of teaching faculty, and library and computer facilities. We sought to determine the current resources of a sample of African radiology education programs. MATERIALS AND METHODS: Site visits were conducted at three separate radiology training programs, one in Ghana and two in South Africa. At each site, the investigator conducted a technology census, assessed library resources, observed daily trainee activities, and interviewed trainees, faculty, and statisticians. RESULTS: African radiology trainees receive considerable training in fluoroscopy, ultrasound, and plain film radiography, but receive considerably less training in nuclear medicine, mammography, magnetic resonance imaging, and interventional radiology. A large amount of equipment in African teaching hospitals is inoperative because of lack of maintenance programs. Faculty to resident ratios in African teaching hospitals are much lower than in American hospitals. Needs of training programs vary greatly from hospital to hospital, and from country to country. CONCLUSION: Radiologists, radiology organizations, and radiology vendors from high-income nations are in a unique position to help Africa's postgraduate radiology training programs fulfill their mission of training Africa's next generation of radiologists. It is desirable that long-term commitments be made to teaching hospitals so that scarce donated resources may be put to the best possible use.

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A microbicide is designed to coat the vaginal epithelium and prevent transmission of HIV. Complete coverage is desired for optimal protection. In vivo factors affecting coverage have not yet been studied. This randomized crossover trial evaluates the effect of gel volume and patient activity upon vaginal epithelial coating. Gynol II gel was mixed with a magnetic resonance imaging (MRI) contrast agent. Ten women self-inserted, on separate visits, 3 or 5 mL of gel and underwent serial MRI scanning both before and after simulated intercourse. Gel spread was dependent upon time and volume. There was modest spread during the first hour and greater spread 6 h after insertion. Five milliliters of gel resulted in statistically significantly greater coverage immediately following insertion, within the first 30 min and at 6 h after insertion. Simulated intercourse greatly enhances gel spread. After simulated intercourse, the distribution of the gel at each volume was similar. Less leakage of gel was reported with the smaller volume.

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Focal hepatic and splenic lesions in the dog are common, and approximately half of such lesions are malignant. Both incidentally discovered lesions and lesions in patients with known malignancies represent diagnostic dilemmas. Ultrasound often fails to characterize such lesions adequately. This uncertainty may result in unnecessary splenectomies and liver biopsies for benign lesions or noncurative surgery for advanced-stage malignancies. In humans, ultrasound largely has been supplanted by computed tomography and magnetic resonance imaging (MRI) for the characterization of focal hepatic and splenic lesions. The inherently high soft tissue contrast of MRI allows the differentiation of benign from malignant hepatic and splenic lesions in the human patients. In this prospective study, 35 focal lesions of either the spleen (n = 8) or the liver (n = 27) were characterized by MRI in 23 dogs. Lesions were presumptively classified as malignant or benign on the basis of MRI findings. Imaging results then were correlated with histopathologic (29) or cytologic (6) evaluation of the lesions. The overall accuracy in differentiating malignant from benign lesions was 94% (33 of 35 lesions). The overall sensitivity and specificity were 100% (95% CI, 78-100%) and 90% (95% CI, 68-99%), respectively. MRI classified malignant hepatic lesions as hepatocellular carcinoma (HCC) in all confirmed cases and correctly predicted the histologic grade of 5 HCC lesions. These results suggest that MRI is a useful modality for abdominal imaging in veterinary patients, and MRI accurately differentiated benign from malignant focal hepatic and splenic lesions in this sample of patients.

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Three-dimensional imaging of the human vagina demonstrates that the cross section can be a "W," rather than an "H," and that intravaginal gel can ascend into the endocervix and presumably into the endometrium.

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OBJECTIVE: To determine the computed tomography (CT) evolution of various pulmonary manifestations of Wegener's Granulomatosis (WG) following appropriate pharmacologic treatment of the disease. METHODS: Eleven patients with WG were identified, each of whom had had at least two CT examinations. CTs were reviewed retrospectively to identify pulmonary lesions of WG. Lesions were categorized as nodules, cavities, lobar atelectasis, pulmonary bands, or infiltrates. To determine the evolution of each individual lesion following pharmacologic treatment, the authors compared the lesions at presentation to their appearances on follow-up CT examinations. RESULTS: A total of 112 lesions were identified (nodules = 70, cavities = 25, lobar atelectasis = 7, pulmonary bands = 6, infiltrates = 4). The mean time interval between CT examinations was 34 weeks (range: 3-248 weeks). Treated nodules tended to become smaller (33/70, 47%), to resolve (14/70, 20%), or to remain unchanged (8/70, 11%). However, the nodules became larger or cavitated in a substantial minority of cases (13/70, 19% and 2/70, 3%, respectively). Although more than half of the treated cavities became smaller (13/25, 52%) or resolved (1/25, 4%), many evolved into nodules (6/25, 24%) or enlarged (5/25, 20%). All cases of lobar atelectasis (14/14, 100%) and transpulmonary bands (6/6, 100%) were unchanged at follow-up. All infiltrates were either resolved (3/4, 75%) or substantially improved (1/4, 25%). CONCLUSION: WG has a wide spectrum of pulmonary manifestations. Nodules, cavities, and infiltrates are among the most common lesions seen on CT. Although these findings tend to improve with treatment, mixed responses are not uncommon. Lobar atelectasis and transpulmonary bands tend not to improve, even with the occurrence of clinical disease remission.

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OBJECTIVE: To perform a phase IV, open-label study of OVULE (Personal Care Products, Skillman, New Jersey) using magnetic resonance imaging (MRI) to describe the release, vaginal distribution and retention of a suspension containing miconazole nitrate in healthy female volunteers. STUDY DESIGN: Three parous and 3 nulligravid women were enrolled. Each subject self-inserted the OVULE on the MRI table and remained recumbent after insertion. MRI images were obtained every 15 minutes for 1 hour and then at predetermined intervals following suspension insertion until the suspension was no longer identified. RESULTS: Placement of the OVULE was in the upper vagina in 4 subjects and in the lower vagina in 1 subject, and the Ovule was expelled in 1 subject. Average time to capsule shell dissolution was 36 minutes. Average time to maximum vaginal mucosal coverage by the suspension was 49 minutes. The average time at which the suspension was last seen in the vagina was 5 hours and 53 minutes. CONCLUSION: MRI can be used to noninvasively quantify the intravaginal spread of a therapeutic antifungal agent. Understanding the intravaginal spread of antifungal agents may lead to further optimization of antifungal preparations as well as to better patient instructions.

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RATIONALE AND OBJECTIVES: The purpose of this study was to determine if continuous arterial spin-labeling perfusion magnetic resonance imaging could be used to detect testicular perfusion in human subjects. MATERIALS AND METHODS: Continuous arterial spin-labeling magnetic resonance perfusion imaging was performed in seven normal male volunteers and in one patient with a painful scrotum following vasectomy. RESULTS: Normal testicular blood flow was demonstrated in 14 of 14 normal testes in seven volunteers, as well as in two normally perfused testes in the post-vasectomy patient. A change in the steady state magnetization was observed in all of the normally perfused testes of the seven volunteers. CONCLUSION: It is possible to detect blood flow to the normally perfused testes using noninvasive spin-labeling perfusion magnetic resonance imaging. This modality could potentially, in future investigations, be used to image patients with suspected testicular torsion and resultant testicular ischemia.

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UNLABELLED: RATIONALE AND OBJECTIVES The purpose of this study was to solicit medical student opinion regarding establishment of a research track within diagnostic radiology residency and to determine the method of implementation most favorable to candidates who self-identified as future researchers. MATERIALS AND METHODS: After the deadline for submitting rank lists (February 21, 2002), a questionnaire was mailed to 588 U.S.-resident medical students who applied to the authors' residency in the 2002 match. Returned questionnaires post-marked before match day (March 21, 2002) were included in the analysis. Students were asked to rate their level of interest in different residency curricula; to indicate whether they were most likely to pursue a position in private practice, clinical academics, or research academics; and to indicate their preferred time of choosing a training track, preferred duration of the residency to dedicate to research, and when they most wished to undertake research. RESULTS: A total of 161 students (27.4%) responded. Overall, students preferred institutions with both clinical and research tracks rather than a single track for all residents, to delay their choice of track for as long as possible, and to do research during postgraduate year 4. Students indicated greatest interest in 3-6 months of research. Among those who self-identified as future academic researchers, interest in a research residency track was greater than among those who indicated the greatest interest in private practice positions. CONCLUSION: Many students are interested in performing research during their radiology residency. Interest in a research track is positively correlated with interest in a research academic career and negatively correlated with interest in private practice.

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To provide effective contraception and protection against sexually transmitted disease, vaginal gels should maximally cover the cervical os and the vaginal epithelium before, during and after intercourse. To non-invasively monitor the intravaginal distribution of an applied intravaginal gel, we performed high-resolution magnetic resonance imaging (MRI) of the female pelvis before, during and after both real and simulated sexual intercourse. We sought to determine whether simulated intercourse with a plastic phallus could be used as a surrogate for real intercourse for such experiments. Dilute gadolinium chelate solution was mixed with Gynol-II gel and introduced intravaginally to volunteer female human subjects using a conventional applicator. MRI was performed at 1.5 Tesla with a surface coil. Imaging of the female pelvis was performed: (1) immediately after insertion of the gel; (2) during real intercourse with a male partner (2 subjects) or simulated intercourse with a plastic phallus (4 subjects); and (3) after completion of real or simulated intercourse. Subjects were studied after application of both 3 mL and 5 mL of vaginal gel. Measurements of gel thickness covering the vaginal mucosa were made digitally using electronic calipers. The bolus of gel is initially located in the upper vaginal canal, superior to the urogenital diaphragm. Both real and simulated intercourse dramatically increases the spread of gel to the lower vagina. The cervix appears to be adequately covered with gel both before and after intercourse. Increasing the volume of the gel increases initial vaginal mucosal coverage but also increases leakage from the introitus. No statistically significant differences in vaginal mucosal coverage were found between patients having undergone real vs. simulated intercourse, or on post-intercourse scans of 3 mL versus 5 mL. MRI is a sensitive, reproducible means of tracking the spread of intravaginal medications.

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Management of carcinoma of the prostate has traditionally been guided by digital rectal examination, and by laboratory data such as serum prostate-specific antigen (PSA) level and histopathologic tumor grade. The introduction of the endorectal coil has improved the ability of magnetic resonance imaging (MRI) to contribute to staging and treatment planning of prostate cancer, especially in cases of confined or locally invasive disease. Exciting research in the fields of magnetic resonance spectroscopy (MRS) and MR-guided intervention of the prostate may soon expand the role of MRI in the diagnosis and treatment of prostate cancer. This article reviews current MRI techniques, the MRI features of prostate cancer, the role and efficacy of MRI in prostate carcinoma staging, and the current and future uses of MR spectroscopy and MR-guided prostate brachytherapy.

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This study was performed to determine the location of a silicone rubber vaginal barrier contraceptive device, the Lea's Shield, in vivo. Two women, one parous and one nulligravid, were enrolled in the study. Surface coil, multiplanar Magnetic Resonance Imaging (MRI) was performed immediately following insertion of the contraceptive device, and was repeated following 35-40 min of normal ambulation by the participant.The contraceptive device was markedly hypointense to pelvic structures on both T1 and T2 weighted images. Its position within the vagina and relationship to the cervix were readily identifiable on MR images. The device was located in the upper vagina and completely covered the cervix in both patients. The valve appeared closed, and there was no apparent pressure on the urethra. The position was not altered by ambulation. In conclusion, MRI was a reproducible and rapid means for noninvasively determining the intravaginal location and orientation of a barrier contraceptive device. After insertion, the Lea's Shield occupies the upper vagina and completely covers the cervix.

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RATIONALE AND OBJECTIVES: A study was performed to determine which factors most influence the program rank lists of U.S. medical students applying for radiology residency and which sources of information about residency programs these medical students value most highly. MATERIALS AND METHODS: Questionnaires were mailed to the 516 U.S. medical students who applied to the authors' radiology residency program in the 2001 National Resident Matching Program match. Respondents were asked to evaluate 23 factors that may have affected their rank lists, on a five-point Likert scale. For data interpretation, factors were categorized as being either within, somewhat within, or outside the control of the program director. Respondents were also asked to evaluate eight potential sources of information about residency programs. RESULTS: The response rate was 23.3% (120 of 516). The three most important factors affecting rank lists were the perceived happiness of current residents within the program, the geographic location of the program, and the academic reputation of the department. Four of the five factors that scored most highly were judged to be outside the program director's control. The most important sources of information were the interview day and personal interactions with residents currently in the program. Program Web sites were rated more highly than the written materials provided. CONCLUSION: Medical students applying for radiology residency use many sources of information and weigh many factors in making their program rank lists. Many of the most influential factors are outside the direct control of the program director.

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