Dual energy CT for evaluation of polycystic kidneys: a multi reader study of interpretation time and diagnostic confidence.

PURPOSE: To compare dual-energy CT (DECT) iodine overlay images with renal mass protocol CT in the evaluation of polycystic kidneys with respect to reading time, diagnostic confidence, and detection of renal lesions that are not definitively benign. METHODS: Following IRB approval, portal venous phase dual-source DECT scans performed between September 2013 and February 2016 from 55 patients (mean age 67 ± 15 years, 31 male, 24 female) with polycystic kidneys (4 or more cysts) were included. For each patient, two image sets were created: (1) DECT post-processed iodine overlay images and (2) simulated renal mass protocol CT images (virtual noncontrast and mixed images). Two radiologists independently retrospectively reviewed both sets at separate time points, evaluating for the presence of lesions that were not definitively benign (enhancing lesions or Bosniak IIF cysts), as well as reading times and Likert scale diagnostic confidence ratings (scaled 1-5) for the presence of non-benign lesions. Reading times were compared with a t test, diagnostic confidence with a McNemar test, and lesion number detection with Cohen's kappa test. RESULTS: Iodine overlay images were read faster (mean 55 ± 26 s) than renal mass protocol (mean 105 ± 51 s) (p < 0.001). Readers assigned the highest diagnostic confidence rating in 64% using iodine overlay series, compared to 17% using renal mass protocol (p < 0.0001). The proportion of patients with recorded lesions was not significantly different between methods (p = 0.62). CONCLUSIONS: DECT improves lesion assessment in polycystic kidneys by decreasing reading times and increasing diagnostic confidence, without affecting lesion detection rates.

Acute Nonhemorrhagic Adrenal Infarction in Pregnancy: 10-Year MRI Incidence and Patient Outcomes at a Single Institution.

OBJECTIVE: The purpose of this study was to retrospectively investigate the MRI incidence of nonhemorrhagic adrenal infarction in pregnant women undergoing MRI evaluation of acute abdominal or flank pain, assess the MRI features quantitatively, and report patient outcomes. MATERIALS AND METHODS: All abdominal MRI examinations of pregnant women with acute pain at one institution from May 2005 to April 2015 were reviewed. The adrenals were evaluated for abnormal morphologic and signal intensity characteristics described in the literature characterizing nonhemorrhagic adrenal infarction and were compared with the contralateral adrenal by paired t tests. The findings were correlated with clinical presentation. Patient demographics and outcomes were gathered from the medical record. RESULTS: Findings of nonhemorrhagic adrenal infarction were present in 5 of 379 (1.3%) examinations of four pregnant patients (mean age, 28 years; range, 20.8-33.9 years; mean gestational age, 26 weeks; range, 16-35 weeks). MRI features included lengthening (mean, 39.8 versus 21.2 mm) (p = 0.005) and increased T2 signal intensity (p = 0.001) of the infarcted adrenal with surrounding edema and without T1 signal intensity suggesting hemorrhage. No alternative diagnosis was identified. All patients presented with severe acute abdominal or flank pain on the same side as the MRI findings, tenderness to palpation, and mild leukocytosis. All women delivered healthy infants. CONCLUSION: Unilateral nonhemorrhagic adrenal infarction was identified in 1.3% of abdominal MRI examinations performed for pregnant women with acute abdominal or flank pain. Knowledge of the MRI characteristics of this entity is important for recognizing it and may prevent further potentially invasive tests, procedures, or missed diagnoses.