Faculty Bibliography

ABSTRACT: Multiple gestations are high-risk compared with singleton pregnancies. Prematurity and intrauterine growth restrictions are the major sources of morbidity and mortality common to all twin gestations. Monochorionic twins are at a higher risk for twin-twin transfusion, fetal growth restriction, congenital anomalies, vasa previa, velamentous insertion of the umbilical cord and fetal death. Therefore, determination of multiple gestation, amnionicity and chorionicity in the first trimester is important. Follow up examinations to evaluate fetal well-being include assessment of fetal growth and amniotic fluid volume, umbilical artery Doppler, nonstress test and biophysical profile. To date, there is a paucity of literature regarding imaging schedules for follow-up. At the very least, antepartum testing in multiple gestations is recommended in all situations in which surveillance would ordinarily be performed in a singleton pregnancy.The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed biennially by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging.

ABSTRACT: It is well recognized that preterm birth is the leading cause of perinatal mortality and morbidity. There is a significant association between cervix length and preterm birth risk. Most authorities consider a cervical length <3 cm as the lower limit of normal. A cervical length >3 cm has a high negative predictive value for delivery less than 34 weeks. A cervical length of <15 mm is moderately predictive ( approximately 70%) of preterm birth within 48 hours. Cervical length is normally distributed and should remain relatively constant until the third trimester. Transabdominal US is the least reliable method of cervical length assessment. The most reliable method of documenting cervical length is transvaginal ultrasound (TVUS). Transperineal US is an alternative for imaging if TVUS is contraindicated, such as with premature rupture of membranes. However, the resolution is decreased compared to TVUS. Short cervix length is the single most important predictive finding for premature delivery. This observation should prompt consultation for high risk obstetrical care and consideration of other management options such as cerclage or activity restriction.The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed biennially by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging

To determine the added value of reimaging the female pelvis with ultrasound (US) immediately following multidetector CT (MDCT) in the emergent setting. CT and US exams of 70 patients who underwent MDCT for evaluation of abdominal/pelvic pain followed by pelvic ultrasound within 48 h were retrospectively reviewed by three readers. Initially, only the CT images were reviewed followed by evaluation of CT images in conjunction with US images. Diagnostic confidence was recorded for each reading and an exact Wilcoxon signed rank test was performed to compare the two. Changes in diagnosis based on combined CT and US readings versus CT readings alone were identified. Confidence intervals (95%) were derived for the percentage of times US reimaging can be expected to lead to a change in diagnosis relative to the diagnosis based on CT interpretation alone. Ultrasound changed the diagnosis for the ovaries/adnexa 8.1% of the time (three reader average); the majority being cases of a suspected CT abnormality found to be normal on US. Ultrasound changed the diagnosis for the uterus 11.9% of the time (three reader average); the majority related to the endometrial canal. The 95% confidence intervals for the ovaries/adnexa and uterus were 5-12.5% and 8-17%, respectively. Ten cases of a normal CT were followed by a normal US with 100% agreement across all three readers. Experienced readers correctly diagnosed ruptured ovarian cysts and tubo-ovarian abscesses (TOA) based on CT alone with 100% agreement. US reimaging after MDCT of the abdomen and pelvis is not helpful: (1) following a normal CT of the pelvic organs or (2) when CT findings are diagnostic and/or characteristic of certain entities such as ruptured cysts and TOA. Reimaging with ultrasound is warranted for (1) less-experienced readers to improve diagnostic confidence or when CT findings are not definitive, (2) further evaluation of suspected endometrial abnormalities. A distinction should be made between the need for immediate vs. follow-up imaging with US after CT

Premenopausal women who present with acute pelvic pain frequently pose a diagnostic dilemma, exhibiting nonspecific signs and symptoms, the most common being nausea, vomiting, and leukocytosis. Diagnostic considerations encompass multiple organ systems, including obstetric, gynecologic, urologic, gastrointestinal, and vascular etiologies. The selection of imaging modality is determined by the clinically suspected differential diagnosis. Thus, a careful evaluation of such a patient should be performed and diagnostic considerations narrowed before a modality is chosen. Transvaginal and transabdominal pelvic sonography is the modality of choice when an obstetric or gynecologic abnormality is suspected, and computed tomography is more useful when gastrointestinal or genitourinary pathology is more likely. Magnetic resonance imaging, when available in the acute setting, is favored over computed tomography for assessing pregnant patients for nongynecologic etiologies because of the lack of ionizing radiation. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every two years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment

OBJECTIVE: The purpose of this article is to compare 3D T2-weighted sampling perfection with application-optimized contrast with different flip-angle evolutions (SPACE) with three-plane 2D turbo-spin echo (TSE) sequences for female pelvic imaging at 3 T. MATERIALS AND METHODS: Twenty women were imaged with 2D TSE and 3D SPACE sequences. Three radiologists independently assessed image quality, diagnostic quality, and artifacts; measured normal anatomic structures; evaluated pathologic abnormalities; and recorded interpretation time. Readers subsequently performed a side-by-side comparison, and their preferences were graded according to overall interpretation, sharpness of lesion edges, motion and other artifacts, uterine and cervical zonal anatomy distinction, identification of adnexal pathologic abnormalities, and distinction between fat and fluid. Quantitative comparison of relative signal intensity and relative tissue contrast was performed. RESULTS: The mean acquisition time of 3D SPACE was significantly shorter than that of 2D TSE (6 minutes 35 seconds vs 8 minutes 50 seconds; p < 0.005). Intrareader agreement between interpretations of 2D and 3D sequences was excellent. There were no significant differences among readers in detecting artifacts, normal structures, and pathologic abnormalities or in determining endometrial thickness, image quality, or interpretation time (p > 0.05). Except for distinctions between fat and fluid, the average reader score indicated a slight preference for the 3D sequence. Three-dimensional multiplanar reconstructions were helpful but not considered essential. Relative agreement between readers was moderate (r >/= 0.4) to strong (r >/= 0.7). The relative signal intensity was higher for fat and bladder fluid on the 3D sequence than on the 2D sequence (p = 0.014 and p = 0.018, respectively). Relative tissue contrast was higher for the 3D sequence (p < 0.05), with no significant difference in bladder or fat contrast (p = 0.31) but a trend toward more superior contrast on the 2D sequence. CONCLUSION: At 3 T, 3D SPACE has similar image quality and diagnostic quality with shorter scan time when compared with 2D TSE but with reduced contrast between fat and fluid

In evaluating a woman with abnormal vaginal bleeding, imaging cannot replace definitive histologic diagnosis but often plays an important role in screening, characterization of structural abnormalities, and directing appropriate patient care. Transvaginal ultrasound (TVUS) is generally the initial imaging modality of choice, with endometrial thickness a well-established predictor of endometrial disease in postmenopausal women. Endometrial thickness measurements of </=5 mm and </=4 mm have been advocated as appropriate upper threshold values to reasonably exclude endometrial carcinoma in postmenopausal women with vaginal bleeding; however, the best upper threshold endometrial thickness in the asymptomatic postmenopausal patient remains a subject of debate. Endometrial thickness in a premenopausal patient is a less reliable indicator of endometrial pathology since this may vary widely depending on the phase of menstrual cycle, and an upper threshold value for normal has not been well-established. Transabdominal ultrasound is generally an adjunct to TVUS and is most helpful when TVUS is not feasible or there is poor visualization of the endometrium. Hysterosonography may also allow for better delineation of both the endometrium and focal abnormalities in the endometrial cavity, leading to hysteroscopically directed biopsy or resection. Color and pulsed Doppler may provide additional characterization of a focal endometrial abnormality by demonstrating vascularity. MRI may also serve as an important problem-solving tool if the endometrium cannot be visualized on TVUS and hysterosonography is not possible, as well as for pretreatment planning of patients with suspected endometrial carcinoma. CT is generally not warranted for the evaluation of patients with abnormal bleeding, and an abnormal endometrium incidentally detected on CT should be further evaluated with TVUS

Computed tomography (CT) is not generally advocated as the first-line imaging examination for disorders of the female pelvis. However, multidetector CT is often the modality of choice for evaluating nongynecologic pelvic abnormalities, particularly in emergent settings, in which all the pelvic organs are invariably assessed. Incidental findings of uterine and cervical contrast enhancement in such settings may easily be mistaken for abnormalities, given the broad spectrum of anatomic variants and enhancement patterns that may be seen in the normal uterus and cervix. The authors' review of CT and magnetic resonance (MR) imaging enhancement patterns, augmented by case examples from their clinical radiology practice, provides a solid foundation for understanding the spectrum of normal uterine and cervical appearances and avoiding potential pitfalls in the diagnosis of benign cervical lesions, adenomyosis, infection, malignancy, and postpartum effects. This information should help radiologists more confidently differentiate between normal and abnormal CT findings and, when CT findings are not definitive, offer appropriate recommendations for follow-up ultrasonography or MR imaging. (c) RSNA, 2011

OBJECTIVE: The objective of this article is to illustrate the MDCT appearances of several commonly encountered foreign bodies and devices in the female pelvis. CONCLUSION: The presence of a foreign body or device in the female pelvis can be a potential source of confusion to radiologists, particularly to the inexperienced reader. Familiarity with the normal appearances and locations of these devices on MDCT allows their accurate identification and detection of associated complications

PURPOSE: To determine if pretreatment apparent diffusion coefficient (ADC) of leiomyomas could predict volumetric response (VR) following uterine artery embolization (UAE). MATERIALS AND METHODS: We retrospectively studied 11 women who underwent pelvic MRI before and >120 days following UAE. MRI included conventional and diffusion weighted imaging sequences. Percentage change in leiomyoma volume was determined by multiplanar T2-weighted imaging. A Pearson correlation coefficient was calculated between leiomyoma VR following UAE and the following pre-embolization parameters: initial volume, relative enhancement, relative T2 signal intensity (SI) and ADC. Receiver operating characteristic (ROC) curve analysis was used to determine the sensitivity and specificity of ADC for predicting volumetric response. RESULTS: Twenty-eight leiomyomas were included with a mean interval from UAE to follow-up MRI of 207 days. The preprocedural volume of the leiomyomas ranged from 18 to 182 cm(3) (median 47 cm(3)). and ADC ranged from 0.37 to 1.71 mm(2)/s (mean 0.80 mm(2)/s). All leiomyomas were 100% necrotic following UAE. Leiomyoma VR following UAE was 48% +/- 3.5%. with significant correlation between VR and ADC (r = 0.41; P = 0.017) but no correlation with initial leiomyoma volume, relative T2 SI, or relative enhancement. Using a threshold of 0.875 x 10(-3) mm(2)/s, ADC could predict > 50% VR with sensitivity and specificity of 70% and 83%, respectively. CONCLUSION: Pre-UAE ADC of leiomyomas correlated significantly with percent VR following UAE. In contrast, no correlation was seen between VR post-UAE and conventional imaging findings. This suggests that VR following UAE depends on leiomyoma histology reflected in DWI rather than features revealed by conventional MRI

The majority of women with ovarian cancer have advanced stage disease at the time of diagnosis and a poor 5 year survival rate. Hence, screening has been investigated in the hopes of improving survival by diagnosing ovarian cancer at an earlier stage. Most screening methods thus far have included ultrasound and/or serum tumor markers. However, low prevalence of the disease, high false positive rate of current screening methods, and the probable rapid growth of most ovarian carcinomas from no defined precursor lesion, all contribute to difficulty in screening for ovarian cancer. While screening may be able to detect ovarian cancer at an earlier stage, adequate data is presently lacking on whether screening improves survival. The results of ongoing large clinical trials will be available in a few years and should provide critical information regarding the usefulness of screening. Pending results of those large clinical trials, screening is not currently recommended for women at average risk for ovarian cancer. Screening is most likely to be performed in women with an increased familial risk of ovarian cancer, but patients should be aware that even with this risk factor, there is currently insufficient evidence to know if screening is effective. New screening methods, including new or multiple serum markers and proteomics, are also being investigated