David W. Swenson

Ovarian and tubal torsion: imaging findings on US, CT, and MRI

Accurate diagnosis of adnexal torsion is often challenging, as clinical presentation is nonspecific and the differential for pelvic pain is broad. However, prompt diagnosis and treatment is critical to good clinical outcomes and preservation of the ovary and/or fallopian tube. Ultrasound (US) imaging is most frequently used to assess torsion. However, as computed tomography (CT) utilization in the emergency setting has increased, there are times when CT is the initial imaging test. Additionally, the nonspecific clinical presentation may initially be interpreted as gastrointestinal in etiology, where CT is the preferred exam. For these reasons, it is imperative to know the findings of adnexal torsion on CT as well as US. Magnetic resonance imaging (MRI) is helpful in cases where the diagnosis remains unclear and is particularly helpful in the young or pregnant patient with equivocal sonographic findings, as it provides excellent soft tissue contrast without ionizing radiation. This article will illustrate the findings of surgically confirmed ovarian and fallopian tube torsion on US, CT, and MRI, including those in the pregnant patient. Ovarian enlargement, adnexal mass, twisting of the vascular pedicle, edematous and heterogeneous appearance of the ovary, peripheral ovarian follicles, free fluid, uterine deviation towards the side of torsion, adnexal fat stranding, tubal dilatation, and decreased adnexal enhancement will be reviewed. Familiarity with the range of imaging findings across multiple modalities is key to improving the likelihood of timely diagnosis and therefore improved clinical outcomes.

Ovarian torsion: Case–control study comparing the sensitivity and specificity of ultrasonography and computed tomography for diagnosis in the emergency department

OBJECTIVE Evaluate the sensitivity and specificity of pelvic ultrasound (US) and abdominopelvic computed tomography (CT) for the identification of ovarian torsion in women presenting to the emergency department with acute lower abdominal or pelvic pain. MATERIALS AND METHODS This is a retrospective study of 20 cases of ovarian torsion and 20 control patients, all of whom had both US and CT performed in the emergency department. Two radiologists who were blinded to clinical data interpreted all studies as (1) demonstrating an abnormal ovary or not, and (2) suggestive of torsion or not. Sensitivity, specificity and interobserver variation were calculated for each imaging modality. RESULTS Pelvic US was interpreted as demonstrating an abnormal ovary in 90.0% of ovarian torsion cases by reader 1, and in 100.0% by reader 2, whereas CT was interpreted as revealing an abnormal ovary in 100.0% of torsion cases by both readers. Pelvic US for ovarian torsion was 80.0% sensitive (95% CI, 58.4-91.9%) and 95.0% specific (95% CI, 76.4-99.1%) for reader 1, while 80.0% sensitive (95% CI, 58.4-91.9%) and 85.0% specific (95% CI, 64.0-95.0%) for reader 2. Interobserver agreement for pelvic US was fair (Kappa=0.60). Abdominopelvic CT for ovarian torsion was 100.0% sensitive (95% CI, 83.9-100.0%) and 85.0% specific (95% CI, 64.0-94.5%) for reader 1, while 90.0% sensitive (95% CI, 69.9-97.2%) and 90.0% specific (95% CI, 69.9-97.2%) for reader 2. Interobserver agreement was excellent (Kappa=0.85). CONCLUSION The diagnostic performance of CT is not shown to be significantly different from that of US in identifying ovarian torsion in this study. These results suggest that when CT demonstrates findings of ovarian torsion, the performance of another imaging exam (i.e. US) that delays therapy is unlikely to improve preoperative diagnostic yield.

Utility of Routine Barium Studies After Adjustments of Laparoscopically Inserted Gastric Bands

OBJECTIVE The purposes of this study were to assess the utility of barium studies after adjustments of laparoscopically inserted gastric bands and to identify a threshold stomal diameter for predicting which bands should be loosened because of excessive tightening. MATERIALS AND METHODS A total of 246 patients with laparoscopically inserted adjustable gastric bands underwent 668 routine band adjustments and barium studies after each adjustment. Forty-one barium studies of 30 patients with tight bands necessitating readjustment were compared with barium studies of 41 patients acting as controls. Barium studies of nine patients with obstructive symptoms before adjustment were reviewed to correlate stomal diameter with symptoms. The data were analyzed for a threshold stomal diameter below which obstructive symptoms were likely to develop. RESULTS Mean stomal diameters were 2.9 mm for the group with tight bands after routine adjustment, 9.5 mm for the control group, and 5.1 mm for the group with obstructive symptoms. Thirty-nine of the 41 studies of tight bands after routine adjustment showed stomal diameters less than 6 mm. Seven of nine patients with obstructive symptoms and none of the 41 control patients had stomal diameters measuring less than 6 mm. Conversely, 40 of 41 control patients and two of nine patients with obstructive symptoms had stomal diameters greater than 6 mm. In none of the 41 cases in which the band was tight after routine adjustment was the stomal diameter greater than 6 mm. Thus, 6 mm was the threshold stomal diameter below which bands should be loosened. CONCLUSION A stomal diameter of less than 6 mm after routine adjustment of a laparoscopically inserted gastric band can cause obstructive symptoms, so the band should be loosened in these patients. In contrast, a stomal diameter greater than 7 mm is unlikely to cause obstructive symptoms, so band loosening usually is not required.

Survey of gadolinium-based contrast agent utilization among the members of the Society for Pediatric Radiology: a Quality and Safety Committee report

BackgroundGadolinium-based contrast agents (GBCAs) have been used for magnetic resonance (MR) imaging over the last three decades. Recent reports demonstrated gadolinium retention in patients’ brains following intravenous administration. Since gadolinium is a highly toxic heavy metal, there is a potential for adverse effects from prolonged retention or deposition, particularly in children. For this reason, the Society (SPR) for Pediatric Radiology Quality and Safety committee conducted a survey to evaluate the current status of GBCAs usage among pediatric radiologists.ObjectiveTo assess the usage of GBCAs among SPR members.Materials and methodsAn online 15-question survey was distributed to SPR members. Survey questions pertained to the type of GBCAs used, protocoling workflow, requirement of renal function or pregnancy tests, and various clinical indications for contrast-enhanced MRI examinations.ResultsA total of 163 survey responses were compiled (11.1% of survey invitations), the majority of these from academic institutions in the United States. Ninety-four percent reported that MR studies are always or usually protocoled by pediatric radiologists. The most common GBCA utilized by survey respondents were Eovist (60.7%), Ablavar (45.4%), Gadovist (38.7%), Magnevist (34.4%) and Dotarem (32.5%). For several clinical indications, survey responses regarding GBCA administration were concordant with American College of Radiology (ACR) Appropriateness Criteria, including seizures, headache and osteomyelitis. For other indications, including growth hormone deficiency and suspected vascular ring, survey responses revealed potential overutilization of GBCAs when compared to ACR recommendations.ConclusionSurvey results demonstrate that GBCAs are administered judiciously in children, yet there is an opportunity to improve their utilization with the goal of reducing potential future adverse effects.

Prenatal MRI characterization of brainstem glioma

We describe a unique case of prenatally diagnosed diffuse brainstem glioma, detected during routine obstetric ultrasound and characterized with fetal magnetic resonance imaging. The diagnosis was supported by early postpartum imaging and confirmed at autopsy. Few examples of these rare lesions have been described in neonates by imaging and fewer cases have been confirmed by histopathological examination. Our case contributes to the limited literature concerning the clinical, MRI, and pathological correlates of brainstem gliomas in the perinatal period.

Response Evaluation Criteria in Solid Tumors (RECIST) following neoadjuvant chemotherapy in osteosarcoma

In osteosarcoma, patient survival has not changed in over 30 years. Multiple phase II trials have been conducted in osteosarcoma using the Response Evaluation Criteria in Solid Tumors (RECIST) as a primary endpoint; however, none of these have revealed new treatment strategies. We investigated RECIST in newly diagnosed patients who received neoadjuvant chemotherapy proven to be beneficial.

Pediatric Emergency Magnetic Resonance Imaging: Current Indications, Techniques, and Clinical Applications

MR imaging plays an important role in the detection and characterization of several pediatric disease entities that can occur in the emergent setting because of its cross-sectional imaging capability, lack of ionizing radiation exposure, and superior soft tissue contrast. In the age of as low as reasonably achievable, these advantages have made MR imaging an increasingly preferred modality for diagnostic evaluations even in time-sensitive settings. In this article, the authors discuss the current indications, techniques, and clinical applications of MR imaging in the evaluation of pediatric emergencies.

Practical Imaging Strategies for Acute Appendicitis in Children

OBJECTIVE Diagnosing pediatric appendicitis is difficult because clinical findings are nonspecific. Improved accuracy can be obtained with ultrasound (US), CT, or MRI, despite considerable variation in their use at different institutions. This article reviews the evidence for best practices in imaging pediatric appendicitis. CONCLUSION When each modality is optimally used, a stepwise imaging approach that begins with graded compression US and proceeds to CT or MRI in select cases is currently best practice.