Detection of Colorectal Hepatic Metastases Is Superior at Standard Radiation Dose CT versus Reduced Dose CT.

Purpose To evaluate colorectal cancer hepatic metastasis detection and characterization between reduced radiation dose (RD) and standard dose (SD) contrast material-enhanced CT of the abdomen and to qualitatively compare between filtered back projection (FBP) and iterative reconstruction algorithms. Materials and Methods In this prospective study (from May 2017 through November 2017), 52 adults with biopsy-proven colorectal cancer and suspected hepatic metastases at baseline CT underwent two portal venous phase CT scans: SD and RD in the same breath hold. Three radiologists, blinded to examination details, performed detection and characterization of 2-15-mm lesions on the SD FBP and RD adaptive statistical iterative reconstruction (ASIR)-V 60% series images. Readers assessed overall image quality and lesions between SD FBP and seven different iterative reconstructions. Two nonblinded consensus reviewers established the reference standard using the picture archiving and communication system lesion marks of each reader, multiple comparison examinations, and clinical data. Results RD CT resulted in a mean dose reduction of 54% compared with SD. Of the 260 lesions (233 metastatic, 27 benign), 212 (82%; 95% confidence interval [CI]: 76%, 86%) were detected with RD CT, whereas 252 (97%; 95% CI: 94%, 99%) were detected with SD (P < .001); per-lesion sensitivity was 79% (95% CI: 74%, 84%) and 94% (95% CI: 90%, 96%) (P < .001), respectively. Mean qualitative scores ranked SD images as higher quality than RD series images, and ASIR-V ranked higher than ASIR and Veo 3.0. Conclusion CT evaluation of colorectal liver metastases is compromised with modest radiation dose reduction, and the use of iterative reconstructions could not maintain observer performance. © RSNA, 2018.

Bilateral adrenal hemorrhage: an overlooked cause of hypotension.

Bilateral adrenal hemorrhage resulting in acute adrenal insufficiency is a rare complication of anticoagulant therapy. We present the case of a patient who came to the Emergency Department with unsuspected adrenal insufficiency, followed by a second visit within 1 month with shock, to demonstrate the importance of early detection and treatment.

Multidetector computed tomography follow-up of hypoattenuating small liver lesions in patients with rectal cancer.

OBJECTIVE: To study the behavior of hypoattenuating liver lesions, deemed too small to characterize at baseline scanning with multidetector computed tomography (CT), in patients with rectal cancer. METHODS: Retrospective review of locally advanced rectal cancer patients from a radiation oncology therapy database was conducted. Patients who presented before neoadjuvant chemoradiation without metastases at baseline CT and with follow-up scans for at least 1 year after therapy were evaluated. CT studies were reviewed for the presence and change in size of hypoattenuating liver lesions (<15 mm) at baseline and follow-up. RESULTS: A total of 616 consecutive patients from the radiotherapy database were reviewed. Of these, 70 patients with a total of 163 hepatic lesions met the selection criteria. The mean patient age was 62.4 years (range, 26-85 years). All patients subsequently underwent surgery and adjuvant chemotherapy. The mean time of radiographic imaging from baseline CT to most recent surveillance CT was 3.3 years (range, 1.1-7.4 years). Two radiologists independently reviewed the CTs. The lesions were stable in 56 of 70 (80.0%, 95% confidence interval: 69%, 89%) patients. Of 163 lesions, 148 (90.8%) were stable, 8 (4.9%) regressed, and 7 (4.3%) progressed in size. No significant difference in results was found for patients stratified according to T-stage (P = 0.41) and N-stage (P > 0.99). CONCLUSION: In patients with rectal cancer, majority of small hypoattenuating liver lesions remain stable and are treated as benign lesions, at multidetector CT follow-up of more than a year. Nevertheless, hepatic lesion stability during systemic therapy should still be interpreted with caution and closely followed for at least 1 year after completion of therapy.

Acute non-traumatic maternal illnesses in pregnancy: imaging approaches.

The imaging methods used to obtain diagnostic information for pregnant patients presenting with acute non-traumatic maternal illnesses have been reviewed. Conditions affecting the gastrointestinal tract, urinary tract, uterus, adnexae, central nervous system and chest have been investigated via a variety of imaging methods, which include ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), intravenous pyelography (IVP), angiography and fluoroscopy. The method of choice, application, and safety to the mother and fetus are considered for investigation of each condition.

Patterns of diagnostic error in trauma abdominal CT.

OBJECTIVE: To define patterns of diagnostic error in the interpretation of trauma abdominal CT. MATERIALS AND METHODS: Two hundred fifty-four out of 1751 abdominal CT scans performed for evaluation of trauma had a definite or equivocal diagnosis of an abdominal injury. Cases were re-read initially without reference to the original reports, in which 44 potential diagnostic errors were identified. A panel of two or three expert readers reviewed each of the 44 cases along with the original report to evaluate the diagnostic error and to search for patterns among the errors. RESULTS: Thirty-one of the 254 CT scans (12%) that were re-read contained non-trivial mistakes that could affect patient outcome. Seventeen were false negative and 14 were false positive. Diagnostic errors were found in the liver, spleen, kidney, retroperitoneum, and peritoneal cavity. Patterns of false-negative diagnosis included missed vascular contrast extravasation, missed hemoperitoneum, and missed right retroperitoneal hematoma. Patterns of false-positive diagnosis included: periportal edema or blood tracking, called a liver laceration; respiratory motion, called a splenic or renal injury; and linear or round lucencies in the spleen or liver, called a laceration. CONCLUSION: Diagnostic errors in interpreting trauma abdominal CT cluster in several recurring patterns. Awareness of these patterns may assist readers in avoiding future errors.