Evaluation of Potential Cumulative Risk of Multiple 1.5-T MRI Examinations in Patients With Cardiac Implanted Electronic Devices.

Although professional societies now support MRI in patients with nonconditional (legacy) cardiac implanted electronic devices (CIEDs), concern remains regarding potential cumulative effects of serial examinations. We evaluated 481 patients with CIEDs who underwent 599 1.5-T MRI examinations (44.6% cardiac examinations), including 68 patients who underwent multiple examinations (maximum, seven examinations). No major events occurred. The minor adverse event rate was 5.7%. Multiple statistical evaluations showed no increase in adverse event rate with increasing number of previous examinations.

Non-visualization of the ovary on CT or ultrasound in the ED setting: utility of immediate follow-up imaging.

PURPOSE: In the setting of female patients in the ED receiving both a CT scan and ultrasound of the pelvis, we compared the studies to assess the diagnostic value of non-visualization of the ovary in predicting the absence of ovarian disease. METHODS: A retrospective review of the electronic medical record identified adult female non-pregnant patients who received both a CT abdomen and pelvis and a transabdominal and transvaginal pelvic ultrasound within a 48-h period through the emergency department. The imaging studies were blindly reviewed to evaluate the ovaries on each CT and US independently. Ovaries were characterized as normal, non-visualized, or abnormal requiring follow-up. All cases of non-visualized ovaries were compared to the appearance on the corresponding exam for each patient, and assessed for agreement (normal or non-visualized) or disagreement (abnormal). Subsequently, the electronic medical record was used as a reference standard to assess the presence or absence of ovarian pathology over the subsequent ninety days. Statistical analysis was performed utilizing a McNemar test with a 95% confidence interval. RESULTS: A total of 181 patients were included in the study (age range 18-75). Of these, 36 patients had non-visualization of one ovary (21 patients) or both ovaries (15 patients) on either study. On CT, 18 ovaries were non-visualized, with no cases of disagreement on ultrasound or subsequent short-term follow-up (NPV 100%). On ultrasound, 39 ovaries were non-visualized, with three of these adnexae appearing abnormal on CT (NPV 92%): one with an enlarged ovary and two with hydrosalpinx. No ovarian abnormalities were evident on chart follow-up. Significant correlation of agreement between normal and non-visualized pairs on CT and US was observed (p = 0.025, McNemar). There was a combined NPV of 94% regardless of modality for the absence of ovarian pathology in the case of non-visualization. The most common abnormal imaging findings associated with non-visualized ovaries were uterine fibroids and hemoperitoneum. CONCLUSION: The absence of detection of the ovary on pelvic US or CT is highly predictive of the lack of ovarian abnormality on short-term follow-up, and does not typically require additional imaging to exclude ovarian disease.