The Role of Positron Emission Tomography/Magnetic Resonance Imaging in Gynecological Malignancies Accurate oncological staging for early detection is of utmost importance in patient care and increasing the overall patient survival outcome. Hybrid imaging in the form of positron emission tomography (PET)/computed tomography has been successfully implemented in oncological imaging and, where available, has been used consistently in patients with gynecologic malignancies. The implementation of PET/magnetic resonance imaging (MRI) enables high-quality assessment of gynecological malignancies by combining the diagnostic advantages of metabolic information of PET along with the high-resolution anatomical and functional information from the MRI to provide precise information about staging, recurrence, and metastases. This article will review the various applications of PET/MRI in gynecological cancer.

Ovarian Cancer Genetics and Implications for Imaging and Therapy Ovarian cancer is the second most common gynecologic malignancy in the United States. Ovarian cancer has a dismal prognosis when diagnosed at an advanced stage. Therapy for these cancers is determined not only by stage but also by their heterogeneous pathologic features, genetic mutations, and biology. In this review, we will discuss types of epithelial ovarian cancer, and their associated genetic mutations and the implications for imaging and treatment.

Von Meyenburg Complex: Current Concepts and Imaging Misconceptions Von Meyenburg complexes, also known as biliary hamartomas, are ductal plate malformations that are usually diagnosed on imaging studies when there are multiple as small hepatic cysts. However, because of variations in histology, they actually have a wide spectrum of imaging appearances ranging from solid, to mixed solid and cystic, to cystic lesions. The objective of the review is to provide up-to-date information about the embryopathogenesis of von Meyenburg complexes, their imaging appearances, diagnostic pitfalls, and clinical significance.

Combined Qualitative and Quantitative Assessment of Low-Attenuation Renal Lesions Improves Identification of Renal Malignancy on Noncontrast Computed Tomography Objective The objective of this study was to assess renal lesions measuring less than 20 Hounsfield units (HU) on noncontrast computed tomography (NCT). Methods Twenty-one (18.1%) of 116 consecutive pathologically proven renal cell carcinomas measured less than 20 HU on NCT and were compared with 40 confirmed benign cysts also measuring less than 20 HU. All lesions were assessed qualitatively (heterogeneous or homogenous) by 3 blinded readers and quantitatively with commercially available textural analysis software. Finally, a combined assessment was performed. Results Qualitative assessment performed well (sensitivity, 76%–90%; specificity, 70%–88%). Quantitative assessment revealed mean positive pixels as having the highest performance (area under the curve, 0.912; sensitivity, 90%; specificity, 80% at a cutoff value of 21). The combined assessment, using the mean positive pixel cutoff, improved the sensitivity (reader 1, 100%; reader 2, 95%; and reader 3, 95%). Conclusion Qualitative and quantitative assessments have relatively good performance, but the combination can nearly eliminate renal cell carcinomas being missed on NCT.

Monoexponential and Biexponential Fitting of Diffusional Magnetic Resonance Imaging Signal Analysis for Prediction of Liver Fibrosis Severity Objective The objective of this study is to compare the value of monoexponential and biexponential approach to the diffusion-weighted magnetic resonance imaging signal in the prediction of the liver fibrosis. Methods Forty patients with hepatitis C were included. Quantification of the apparent diffusion coefficient (ADC) and pure molecular diffusion (D), pseudodiffusion (D*), and perfusion fraction (f) was performed using 9 b values (b = 0, 20, 50, 100, 200, 400, 600, 800, 1000 s/mm2). Results Significant fibrosis was found in 14 subjects. Monoexponentally derived ADC parameters were significantly correlated. Apparent diffusion coefficient calculated from all b values and ADC based on high b values were significantly related to the fibrosis grade (P < 0.02), and none of intravoxel incoherent motion parameters presented such an association. Apparent diffusion coefficient based on high b values was the best predictor of significant fibrosis with area under the curve of 0.81, sensitivity of 0.57, and specificity of 0.92. Conclusion Intravoxel incoherent motion parameters did not allow for prediction of the liver fibrosis. Apparent diffusion coefficient calculated based on high b values presents considerable specificity in predicting significant fibrosis.

Imaging Features of Sclerosing Angiomatoid Nodular Transformation in Spleen Purpose The purpose of this study was to evaluate the features of sclerosing angiomatoid nodular transformation (SANT) in spleen on the imaging of computed tomography (CT) and magnetic resonance (MR). Materials and Methods From July 2006 to April 2017, 12 patients with SANT confirmed by pathology were evaluated in a retrospective study. Eight patients were with CT imaging only, 2 patients were with MR imaging only, and 2 patients were with both CT and MR. Three professional senior radiologists analyzed the imaging features on CT and MR. The main characteristic analysis included size, margin, density, signal intensity, and enhancement pattern. The significant enhancement was defined as the degree of enhancement of lesion that is higher than the surrounding spleen parenchyma, and the mild enhancement was defined as the degree of enhancement of lesion that is lower than the surrounding spleen parenchyma. Results All the 12 patients (5 men, 7 women; mean age, 45.8 years; age range, 21–62 years) presented as single lesion without special clinical symptoms. The range of lesions on diameter was from 25 to 80 mm. On CT images, 9 (90%) of 10 presented as hypodense in comparison with the parenchyma of spleen, 1 (10%) of 10 presented as isodense, and calcification was observed in 4 (40%) of 10 cases. On MR images, 4 (100%) of 4 manifested heterogeneous hypointensity on in-phase sequence and 3 (75%) of 4 performed as isointensity on out-of-phase sequence of T1-weighted. On the sequences of T2-weighted and diffusion-weighted image, 4 (100%) of 4 showed hypointensity. On CT and MR enhancement images, the number of significant enhancement and mild enhancement was 2 and 10, respectively. Seven (58%) of 12 showed progressive enhancement with the pattern of “spoke-wheel.” Conclusions Imaging features on CT and MR have a high diagnostic value for SANT, especially when CT combined with MR examination.

Whole-Body Computed Tomography Using Low-Dose Biphasic Injection Protocol With Adaptive Statistical Iterative Reconstruction V: Assessment of Dose Reduction and Image Quality in Trauma Patients Aim This study aimed to evaluate potential dose savings on a revised protocol for whole-body computed tomography and image quality after implementing Adaptive Statistical Iterative Reconstruction V (ASiR-V) algorism for trauma patients and compare it with routine protocol. Materials and Methods One hundred trauma patients were classified into 2 groups using 2 different scanning protocols. Group A (n = 50; age, 32.48 ± 8.09 years) underwent routine 3-phase protocol. Group B (n = 50; age, 35.94 ± 13.57 years) underwent biphasic injection protocol including unenhanced scan for the brain and cervical spines, followed by a 1-step acquisition of the thorax, abdomen, and pelvis. The ASiR-V level was kept at 50% for all examinations, and then studies were reconstructed at 0% ASiR-V level. Radiation dose, total acquisition time, and image count were compared between groups (A and B). Two radiologists independently graded image quality and artifacts between both groups and 2 ASiR-V levels (0 and 50%). Results The mean (±SD) dose-length product value for postcontrast scans in group A was 1602.3 ± 271.8 mGy · cm and higher when compared with group B (P < 0.001), which was 951.1 ± 359.6 mGy · cm. Biphasic injection protocol gave a dose reduction of 40.4% and reduced the total acquisition time by 11.4% and image count by 37.6%. There was no statistically significant difference between the image quality scores for both groups; however, group A scored higher grades (4.62 ± 0.56 and 4.56 ± 0.67). Similarly, the image quality scores for both ASiR-V levels in both groups were not significantly different. Conclusions Biphasic computed tomography protocol reduced radiation dose with maintenance of diagnostic accuracy and image quality after implementing ASiR-V algorism.

Effective Radiation Dose Reduction in Computed Tomography With Iterative Reconstruction in Patients With Urinary Stone Purpose This study aimed to prospectively compare the image quality and visibility of urinary stone on computed tomographic (CT) images at multiple radiation exposure levels from the same patient reconstructed with sinogram-affirmed iterative reconstruction (SAFIRE). Methods This study included 760 patients with urinary stone who underwent CT with simultaneous acquisition at 6 exposures per patient (100% filtered back projection, 75%, 50%, 37.5%, 25%, and 12.5% SAFIRE). Two radiologists independently assessed overall image quality, noise, and stone visibility by using a 5-point scale. Quantitative measurements, including the CT number, image noise, signal-to-noise ratio, contrast-to-noise ratio (CNR), and corresponding figure of merit (FOM), were compared for 100% versus 5 other radiation doses. Results Qualitative overall image quality, noise, and stone visibility according to the location were not inferior at 37.5% exposure compared with 100% exposure, except for the visualization of smaller stones <3 mm. The signal-to-noise ratio and CNR of CT images were increased at 50% exposure compared with 100% exposure. Computed tomographic images at 37.5% exposure reconstructed with SAFIRE had significantly more noise and a lower CNR compared with CT images reconstructed with filtered back projection, based on FOMnoise and FOMCNR. The size-specific dose estimation was 4.1 ± 0.8 mGy at 37.5% exposure. Conclusion Computed tomography performed at 37.5% exposure with SAFIRE may be diagnostically acceptable for the detection of clinically relevant stone.

Nonhemorrhagic Adrenal Infarction in Pregnancy: Magnetic Resonance Imaging and Computed Tomography Evaluation We present the case of unilateral nonhemorrhagic adrenal infarct in a 29-week pregnant 21-year-old woman. The patient presented with right upper quadrant pain, nausea, and vomiting. Ultrasonography of the right upper quadrant and appendix was negative for pathology. Magnetic resonance imaging of the abdomen demonstrated a right nonhemorrhagic adrenal infarct, subsequently confirmed with limited computed tomography of the upper abdomen. This case discusses the clinical presentation and pertinent imaging findings of adrenal infarction in pregnancy.

Gastric Hepatoid Adenocarcinoma: Differentiation From Gastric Adenocarcinoma With Dynamic Contrast-Enhanced Computed Tomographic Findings Purpose This study aimed to describe the computed tomographic (CT) findings of gastric hepatoid adenocarcinoma (GHA) and determine features distinguishing it from gastric adenocarcinoma (GA). Methods Computed tomographic images of pathologically verified GHA (n = 11) and GA (n = 38) were retrospectively reviewed. α-Fetoprotein (AFP), carcinoembryonic antigen (CEA), and CT findings were assessed in our study. Computed tomographic findings included the location, distribution, growth pattern, ulceration, thickness of gastric wall, enhancement pattern, and the ratio of lesion attenuation to aorta CT attenuation. Short diameter of the metastatic lymph nodes, mean short diameter of metastatic lymph nodes, and the ratio of the number of enlarged lymph node on CT to the number of metastatic lymph nodes pathologically were measured and calculated. Data were compared using the χ2 and Student t tests; significant CT criteria were identified using receiver operating characteristic curve. Results α-Fetoprotein, CEA, and CT findings, including the longest short diameter, the mean short diameter, the ratio of the number of enlarged lymph node on CT to the number of metastatic lymph nodes pathologically, the lesion in arterial phase minus portal venous phase, and the lesion/aorta ratio, were statistically significant predictors for the differentiation of GHA from GA (P < 0.05). When only the aforementioned CT findings were used as criteria, the sensitivity and specificity for diagnosing GHA were 82.86% and 90.91%, respectively. When AFP, CEA, and CT findings were used as criteria, sensitivity of 97.14% and specificity of 90.91% were achieved. Conclusions Elevated serum AFP level and CT findings could distinguish GHA and GA with a high degree of accuracy.