Susanna I. Lee

MRI, CT, and PET/CT for ovarian cancer detection and adnexal lesion characterization.

OBJECTIVE The purpose of this article is to describe the role of MR, CT, and PET/CT in the detection of ovarian cancer and the evaluation of adnexal lesions. CONCLUSION The goal of imaging in ovarian cancer detection is to expeditiously distinguish benign adnexal lesions from those requiring further pathologic evaluation for malignancy. For lesions indeterminate on ultrasound, MRI increases the specificity of imaging evaluation, thus decreasing benign resections. CT is useful in diagnosis and treatment planning of advanced cancer. Although (18)F-FDG-avid ovarian lesions in postmenopausal women are considered suspicious for malignancy, PET/CT is not recommended for primary cancer detection because of high false-positive rates.

Ovarian Torsion: Diagnostic Features on CT and MRI With Pathologic Correlation

OBJECTIVE The CT and MRI features of ovarian torsion are illustrated with gross pathologic correlation. Ovarian enlargement with or without an underlying mass is the finding most frequently associated with torsion, but it is nonspecific. A twisted pedicle, although not often detected on imaging, is pathognomonic when seen. Subacute ovarian hemorrhage and abnormal enhancement is usually seen, and both features show characteristic patterns on CT and MRI. Ipsilateral uterine deviation can also be seen. CONCLUSION Diagnostic pitfalls that may mimic ovarian torsion and observations for discriminating them are discussed.

Uterine Smooth-Muscle Tumors with Unusual Growth Patterns: Imaging with Pathologic Correlation

OBJECTIVE This essay illustrates the salient features of variant smooth-muscle tumors on multiple imaging techniques with correlative pathology. We describe how recognition of these features allows the radiologist to distinguish a uterine leiomyoma variant from the classic fibroid or a leiomyosarcoma. Finally, we highlight the role of the radiologist in triaging these patients to surgical versus medical management and in surgical planning. CONCLUSION Parasitic leiomyoma, intravenous leiomyomatosis, disseminated peritoneal leiomyomatosis, and benign metastasizing leiomyoma show key features on multiple imaging techniques that correlate with pathology findings. In the appropriate clinical setting, the radiologist should include these unusual lesions in the broader differential diagnosis of smooth-muscle tumors and, in certain cases, aid in surgical planning.

Body CT Scanning in Young Adults: Examination Indications, Patient Outcomes, and Risk of Radiation-induced Cancer

PURPOSE To quantify patient outcome and predicted cancer risk from body computed tomography (CT) in young adults and identify common indications for the imaging examination. MATERIALS AND METHODS This retrospective multicenter study was HIPAA compliant and approved by the institutional review boards of three institutions, with waiver of informed consent. The Research Patient Data Registry containing patient medical and billing records of three university-affiliated hospitals in a single metropolitan area was queried for patients 18-35 years old with a social security record who underwent chest or abdominopelvic CT from 2003 to 2007. Patients were analyzed according to body part imaged and scanning frequency. Mortality status and follow-up interval were recorded. The Biologic Effects of Ionizing Radiation VII method was used to calculate expected cancer incidence and death. Examination indication was determined with associated ICD-9 diagnostic code; 95% confidence intervals for percentages were calculated, and the binomial test was used to compare the difference between percentages. RESULTS In 21 945 patients, 16 851 chest and 24 112 abdominopelvic CT scans were obtained. During the average 5.5-year (± 0.1 [standard deviation]) follow-up, 7.1% (575 of 8057) of chest CT patients and 3.9% (546 of 13 888) of abdominal CT patients had died. In comparison, the predicted risk of dying from CT-induced cancer was 0.1% (five of 8057, P < .01) and 0.1% (eight of 12 472, P < .01), respectively. The most common examination indications were cancer and trauma for chest CT and abdominal pain, trauma, and cancer for abdominopelvic CT. Among patients without a cancer diagnosis in whom only one or two scans were obtained, mortality and predicted risk of radiation-induced cancer death were 3.6% (215 of 5914) and 0.05% (three of 5914, P < .01) for chest CT and 1.9% (219 of 11 291) and 0.1% (six of 11 291, P < .01) for abdominopelvic CT. CONCLUSION Among young adults undergoing body CT, risk of death from underlying morbidity is more than an order of magnitude greater than death from long-term radiation-induced cancer.

Evaluation of Gynecologic Cancer with MR Imaging, 18F-FDG PET/CT, and PET/MR Imaging

MR imaging and 18F-FDG PET/CT play central and complementary roles in the care of patients with gynecologic cancer. Because treatment often requires combinations of surgery, radiotherapy, and chemotherapy, imaging is central to triage and to determining prognosis. This article reviews the use of the 2 imaging modalities in the initial evaluation of 3 common cancers: uterine cervical, uterine endometrial, and epithelial ovarian. Imaging features that affect management are highlighted, as well as the relative strengths and weaknesses of the 2 modalities. Use of imaging after initial therapy to assess for recurrence and to plan salvage therapy is described. Newer functional and molecular techniques in MR imaging and PET are evaluated. Finally, we describe our initial experience with PET/MR imaging, an emerging technology that may prove to be a mainstay in personalized gynecologic cancer care.

MR Imaging of Malignancies Arising in Endometriomas and Extraovarian Endometriosis

Cancers that arise in ovarian or extraovarian endometriosis are a distinct disease category with a histologic profile different from that of the more common epithelial ovarian cancers and with a better prognosis. Because the malignant transformation of endometriomas is rarely associated with lymphadenopathy or peritoneal carcinomatosis, a high index of suspicion on the part of the radiologist is necessary to establish a timely diagnosis of endometriosis-related ovarian cancers and allow appropriate oncologic management. Although imaging is not currently performed for surveillance of endometriosis, magnetic resonance (MR) imaging is often performed when surgical treatment is under consideration. An optimal MR imaging protocol for the detection of cancer arising in an endometrioma includes a review of subtraction images derived from unenhanced and contrast material-enhanced T1-weighted datasets. Subtraction images provide improved conspicuity of enhancing mural nodules--which are the most sensitive MR imaging sign of malignancy in ovarian endometriosis--against the background of the high-signal-intensity endometriotic cyst. Cancers arising in extraovarian endometriosis typically manifest as solid lesions with intermediate signal intensity on T1- and T2-weighted images, enhancement after the intravenous administration of a gadolinium-based contrast material, and restricted diffusion on diffusion-weighted images and apparent diffusion coefficient (ADC) maps. The signal intensity of myometrium, or, if the uterus is absent, that of the small bowel wall, is used as an internal reference standard for lesion signal intensity. Lesions are considered to have restricted diffusion if they show signal hyperintensity relative to the reference structure on diffusion-weighted images and hypointensity or isointensity relative to that structure on ADC maps. For definitive diagnosis, histopathologic analysis is required.

Body CT During Pregnancy: Utilization Trends, Examination Indications, and Fetal Radiation Doses

OBJECTIVE The objective of our study was to analyze body CT utilization trends, indications, fetal radiation doses, and scanning parameters associated with high fetal radiation doses (defined as > 30 mGy). MATERIALS AND METHODS A retrospective review of all chest and abdominopelvic CT examinations performed between 1998 and 2005 of patients known to be pregnant was conducted. Demographics, gestational age, examination indication, and scan parameters were recorded. Fetal radiation dose was calculated for those abdominopelvic examinations with direct fetal irradiation. RESULTS From a database of more than 170,000 chest and more than 180,000 abdominopelvic CT examinations, 74 chest and 86 abdominopelvic examinations of pregnant patients were identified. Chest CT use increased on average 75%/y/1,000 deliveries in pregnancy versus 19%/y increase in all patients (p = 0.2700). Abdominopelvic CT utilization increase was on average 22%/y/1,000 deliveries in pregnant patients versus 13%/y increase in all patients (p = 0.1865). The most common indication for chest CT during pregnancy was suspected pulmonary embolism (85%, 63/74) and for abdominopelvic CT, suspected appendicitis (58%, 50/86). The average fetal dose from abdominopelvic CT was 24.8 mGy (range, 6.7-56 mGy); one examination exceeded the 50-mGy threshold for increased risk of childhood cancer. Scanning parameters associated with a dose of more than 30 mGy were a pitch of less than 1 (p = 0.0080) and more than one series acquisition (p = 0.0136). CONCLUSION Growth of CT during pregnancy reflects the trend of increased CT utilization in the general population. Avoiding use of CT in pregnant patients with suspected appendicitis would significantly decrease fetal radiation exposure. Abdominopelvic CT during pregnancy should be carefully planned and monitored so as not to exceed the fetal radiation dose for negligible risk.

ACR Appropriateness Criteria on acute pelvic pain in the reproductive age group.

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.

Patients Imaged Early During Admission Demonstrate Reduced Length of Hospital Stay: A Retrospective Cohort Study of Patients Undergoing Cross-Sectional Imaging

PURPOSE The aim of this study was to relate the early use of advanced imaging to length of hospital stay. MATERIALS AND METHODS Among all 33,226 admissions to an urban tertiary care hospital in 2005, the authors identified the 10,005 admissions (30.1%) that included >or=1 advanced imaging study (CT, MRI, or nuclear scintigraphy) during the period from 1 day before admission (day -1) through discharge. The length of stay was calculated, and using the date of the first advanced imaging study performed relative to date of admission (date of service), the residual length of stay (length of stay minus date of service) of each admission was also calculated. For admissions of >or=3 days in duration, the mean length of stay of patients with early imaging (on day -1 or 0) was compared using t test to that of patients with later imaging (on day 1 or 2). For all admissions with advanced imaging, linear regression analysis was applied to length of stay and residual length of stay as a function of date of service. Similar analysis was performed on subgroups classified by examination type (modality and body part) and International Classification of Diseases, Ninth Revision (ICD-9) diagnostic code. RESULTS The mean length of stay was significantly shorter for those imaged on day -1 or 0 compared with day 1 or 2 for all admissions of >or=3 days (8.6 vs 9.0 days, P = .015) and for the following specific subgroups: abdominal CT (8.4 vs 9.7 days, P = .003) and neurologic MR examination types (7.6 vs 8.7 days, P = .03) and abdominal ICD-9 codes (7.5 vs 8.8 days, P = .007). A statistically significant positive correlation was noted between length of stay and date of service for all admissions (slope, 0.27; P < .001) and for the following subgroups: neurologic CT, chest CT, abdominal CT, and nuclear scintigraphy examination types and abdominal ICD-9 codes. CONCLUSION Early imaging with CT, MRI, or nuclear scintigraphy, particularly on the day before or the day of admission, was associated with significantly shorter lengths of stay of inpatients compared with patients who underwent advanced imaging later.

Interventional Radiology in Pregnancy Complications: Indications, Technique, and Methods for Minimizing Radiation Exposure

Complications of pregnancy, whether they occur during gestation or postpartum, often pose complex challenges because they affect two patients (mother and fetus or infant) and because both short- and long-term outcomes must be considered in management decision making. Interventional radiologists play a critical role in treating complications such as ectopic implantation, postpartum hemorrhage, symptomatic ovarian cyst, post-cesarean section fluid collection, obstructive uropathy, and vesicouterine fistula. Interventional radiology offers therapeutic options that obviate surgery, thereby minimizing morbidity and mortality and maximizing the potential for fertility preservation. Such options include chemical injection of an ectopic gestational sac, uterine artery embolization, aspiration and drainage, percutaneous nephrostomy, and suprapubic cystostomy catheter placement. All these procedures are performed with the use of radiologic imaging for guidance. The levels of radiation to which the mother and fetus may be exposed during such procedures are of concern because of potential negative effects on long-term health. However, various methods can be used to lower maternal and fetal radiation dose levels to the minimum needed to accomplish the clinical objective.