Bladder involvement in placenta accreta spectrum disorder with placenta previa: MRI findings and outcomes correlation.

BACKGROUND: Placental accreta spectrum (PAS) disorder with bladder involvement can be associated with maternal and neonatal morbidity. Magnetic resonance imaging (MRI) may provide accurate preoperative diagnoses. OBJECTIVE: This study had 2 aims: to retrospectively review the MRI findings for bladder involvement in PAS with placental previa and to correlate bladder involvement with maternal and neonatal outcomes. MATERIALS AND METHODS: MRI images of 48 patients with severe PAS (increta and percreta) with placenta previa/low-lying placenta were evaluated by 2 experienced radiologists blinded to the final diagnoses. Nine MRI findings and stepwise logistic regression analysis were assessed to identify predictive MRI findings for bladder involvement. The correlations between PAS patients with bladder involvement and clinical outcomes were analyzed using Fisher's exact test. RESULTS: Of the 48 patients, 27 did not have bladder involvement, while 21 did. Logistic regression analysis identified 2 predictive MRI features for bladder involvement. They were abnormal vascularization (OR,6.94; 95 %CI,1.05-45.75) and loss of the chemical shift line at the uterovesical interface (OR, 4.41; 95 %CI, 0.63-30.98). The sensitivity and specificity of the combined MRI features were 38.1 % and 100 %, respectively (p = 0.001). A significant correlation was found between bladder involvement and massive blood loss during surgery (p = 0.022). CONCLUSIONS: PAS with bladder involvement was significantly correlated with massive surgical blood loss. Prenatally, the disorder was predicted with high specificity by the combination of loss of chemical shift artifacts in the steady-state free precession sequence and abnormal vascularization at the uterovesical interface on MRI.

Virtual monochromatic spectral attenuation curve analysis for evaluation of incidentally detected small renal lesions using rapid kilovoltage-switching dual-energy computed tomography.

PURPOSE: To determine whether the spectral attenuation curve on a rapid kilovoltage-switching dual-energy computed tomography (DECT) scan can distinguish enhancing from nonenhancing incidental small (1-4 cm) renal lesions compared with conventional single-energy attenuation changes. METHODS: This retrospective study enrolled 46 patients with 78 renal lesions (24 enhancing; 54 nonenhancing) who underwent DECT with DE mode performed during the portovenous or nephrographic phase. Final diagnosis of enhancing and nonenhancing masses was confirmed by pathology or imaging following the established criteria. Virtual monochromatic images (VMI) were reconstructed, and the slopes between the VMI dataset at 40-70 keV (Slope HU40-70), 40-100 keV (Slope HU40-100), and 40-140 keV (Slope HU40-140) were measured. Visual assessment of the curve pattern was recorded. Diagnostic accuracies were calculated with a cross-validated Mann-Whitney U test, and correlations of quantitative spectral parameters and intraclass correlation coefficient (ICC) were calculated using Spearman's rho correlation. RESULTS: All quantitative and qualitative spectral analysis parameters significantly differentiated the enhancing and nonenhancing lesions (P < 0.001). The optimal slope thresholds calculated by cross-validation for Slope HU40-70, Slope HU40-100, and Slope HU40-140 were 3.0, 1.8 and 1.2, respectively for reader 1 and 3.0, 1.9 and 1.15, respectively for reader 2. Using a slope threshold at all datasets yielded a high diagnostic accuracy of 96 for reader 1 and 95 for reader 2. Using a ∆HU threshold of 20 HU yielded an accuracy of 100. Visual analysis of the curve pattern also yielded high accuracy of 94. CONCLUSIONS: The spectral attenuation curve on rapid kilovoltage-switching DECT gives excellent diagnostic accuracy differentiating between incidental enhancing and nonenhancing renal lesions. This benefit of DECT will be most helpful when the true unenhanced phase is not performed.

Role of Ultrasound and MRI in Diagnosis of Severe Placenta Accreta Spectrum Disorder: An Intraindividual Assessment With Emphasis on Placental Bulge.

BACKGROUND. The "placental bulge" sign (focal area of myometrial-placental bulging beyond the normal uterine contour) on ultrasound (US) or MRI is postulated to represent deeper venous invasion in placenta accreta spectrum (PAS) disorder and may represent severe PAS. OBJECTIVE. The purpose of this study was to evaluate the diagnostic performance and interobserver agreement of US and MRI features for diagnosis of severe PAS, with an emphasis on the placental bulge sign. METHODS. This retrospective study included 62 pregnant women (mean age, 33.2 ± 5.5 [SD] years) with clinically suspected PAS who underwent both US and MRI. Five readers (two maternal-fetal medicine specialists for US, three abdominal radiologists for MRI) independently reviewed images for the given modality, blinded to the final diagnosis, and recorded the presence of a range of findings (nine on US, eight on MRI), including placental bulge. Intraoperative and pathologic findings were used to separate patients into those with and without severe PAS according to International Federation of Gynecology and Obstetrics classification. Diagnostic performance of US and MRI findings for severe PAS was evaluated, multivariable logistic regression was performed, and interob-server agreement was assessed. RESULTS. A total of 58.1% (36/62) of patients had severe PAS. On US, the finding with the highest accuracy for severe PAS was placental bulge (85.5%), which had a sensitivity of 91.7% and specificity of 76.9%. On MRI, the finding with highest accuracy was also placental bulge (90.3%), which had a sensitivity of 94.4% and specificity of 84.6%. In the multivariable regression analysis, placental bulge was an independent predictor of severe PAS on US (odds ratio [OR], 8.94; p = .02) and MRI (OR, 45.67; p = .003). Interobserver agreement analysis showed a kappa value for placental bulge of 0.48 for MRI and 0.40 for US. Given wide 95% CIs, differences among features for a given modality and differences between modalities were not statistically significant. CONCLUSION. The findings suggest a strong performance of placental bulge in diagnosing severe PAS on both US and MRI, with a potentially stronger performance on MRI. Nonetheless, interobserver agreement remains suboptimal for both modalities. CLINICAL IMPACT. Accurate prenatal diagnosis of severe PAS by imaging could help guide maternal counseling and selection of either hysterectomy or uterine-preserving surgery.

Use of dual-energy CT for renal mass assessment.

Although dual-energy CT (DECT) may prove useful in a variety of abdominal imaging tasks, renal mass evaluation represents the area where this technology can be most impactful in abdominal imaging compared to routinely performed contrast-enhanced-only single-energy CT exams. DECT post-processing techniques, such as creation of virtual unenhanced and iodine density images, can help in the characterization of incidentally discovered renal masses that would otherwise remain indeterminate based on post-contrast imaging only. The purpose of this article is to review the use of DECT for renal mass assessment, including its benefits and existing limitations. KEY POINTS: • If DECT is selected as the scanning mode for most common abdominal protocols, many incidentally found renal masses can be fully triaged within the same exam. • Virtual unenhanced and iodine density DECT images can provide additional information when renal masses are discovered in the post-contrast-only setting. • For renal mass evaluation, virtual unenhanced and iodine density DECT images should be interpreted side-by-side to troubleshoot pitfalls that can potentially lead to erroneous interpretation.

Building a dual-energy CT service line in abdominal radiology.

As the access of radiology practices to dual-energy CT (DECT) has increased worldwide, seamless integration into clinical workflows and optimized use of this technology are desirable. In this article, we provide basic concepts of commercially available DECT hardware implementations, discuss financial and logistical aspects, provide tips for protocol building and image routing strategies, and review radiation dose considerations to establish a DECT service line in abdominal imaging. KEY POINTS: • Tube-based and detector-based DECT implementations with varying features and strengths are available on the imaging market. • Thorough assessment of financial and logistical aspects is key to successful implementation of a DECT service line. • Optimized protocol building and image routing strategies are of critical importance for effective use and seamless inception of DECT in routine clinical workflows.

Correlation Between Apparent Diffusion Coefficient Values of the Renal Parenchyma and Estimated Glomerular Filtration Rates on 3-T Diffusion-Weighted Echo-Planar Magnetic Resonance Imaging.

OBJECTIVE: To evaluate the relationship between the apparent diffusion coefficient (ADC) values of renal parenchyma and estimated glomerular filtration rates (eGFR). METHODS: Data on 216 patients examined by 3-T magnetic resonance imaging for various reasons were retrospectively collected. RESULTS: There was a significant linear correlation between the ADC values and eGFRs (r = 0.254, P < 0.001). The ADC values in patients with an eGFR of less than 60 mL/min per 1.73 m were significantly lower than those with an eGFR of 60 mL/min per 1.73 m or greater. The mean ADC value of patients with grouped stage 2 disease was significantly higher than those with grouped stage 3 of chronic kidney disease (P < 0.01). CONCLUSIONS: The ADC value of renal parenchyma may be a promising marker for the determination of patients with normal to mild reduction in renal function (eGFR ≥60 mL/min per 1.73 m) versus those with a moderate to severe reduction in renal function (eGFR <60 mL/min per 1.73 m).

Diagnostic performance of qualitative and quantitative shear wave elastography in differentiating malignant from benign breast masses, and association with the histological prognostic factors.

BACKGROUND: To determine the diagnostic performance of qualitative and quantitative shear wave elastography (SWE) and the optimal cutoff values of the quantitative SWE parameters in differentiating malignant from benign breast masses, and to evaluate the association between the quantitative SWE parameters and histological prognostic factors. METHODS: A gray scale ultrasound and SWE were prospectively performed on a total of 244 breast masses (148 benign, and 96 malignant) in 228 consecutive patients before an ultrasound-guided needle biopsy. The qualitative SWE and quantitative SWE parameters (the mean elasticity, maximum elasticity, and elasticity ratio) were measured in each mass. The diagnostic performance of SWE and the optimal cutoff values of the quantitative SWE parameters were obtained. An association analysis of the parameters and histological prognostic factors was performed. RESULTS: The malignant masses had a more heterogeneous pattern on the qualitative SWE than benign masses (P<0.001). The quantitative SWE parameters of the malignant masses were higher than those of the benign masses (P<0.001); the mean elasticity, maximum elasticity, and elasticity ratio of the benign masses were 19.73 kPa, 23.98 kPa, and 2.78, respectively; and the mean elasticity, maximum elasticity, and elasticity ratio of the malignant masses were 88.13 kPa, 98.48 kPa, and 10.64, respectively. The optimal cutoff value of the mean elasticity was 30 kPa, of the maximum elasticity was 36 kPa, and of the elasticity ratio was 4.5. The maximum elasticity had the highest AUC. Combining the three SWE parameters to differentiate between the malignant and benign masses increased the negative predictive value (NPV), which correctly downgraded 72.73% of BI-RADS category 4A masses to BI-RADS category 3. No statistically significant association was found between the quantitative SWE parameters and the tumor grading, tumor types, axillary lymph node statuses, or molecular subtypes of the breast cancers (P>0.05). CONCLUSIONS: The qualitative and quantitative SWE provided good diagnostic performance in differentiating malignant and benign masses. The maximum elasticity of the quantitative SWE parameters had the best diagnostic performance. Adding the three combined quantitative SWE parameters to the BI-RADS category 4A masses potentially downgraded them to BI-RADS category 3 and avoided unnecessary biopsies. No statistically significant association was found between the quantitative SWE parameters and the histological prognostic factors.

Clinical, mammographic, and ultrasonographic characteristics of diabetic mastopathy: A case series.

PURPOSE: Diabetic mastopathy (DMP) is a rare benign breast lesion that mimics breast cancer on ultrasound. Our aims were to identify patient characteristics and imaging features of the disease. METHODS: We conducted retrospective searches of our database for DMP lesions that were pathologically confirmed between January 2004 and November 2015. Mammographic and ultrasound features were reviewed by two experienced radiologists. RESULTS: Twelve women were identified with 16 lesions. Most patients (83%) had type 2 diabetes mellitus (DM) and over half were insulin-dependent (58.3%), with a mean time of 16.9 years between the diagnosis of DM and that of DMP. There were negative findings on mammography for 46.7% of the lesions, including larger-sized lesions. Ultrasound revealed various features, including irregular shape (81.3%), indistinct margins (100%), parallel orientation to the chest wall (93.8%), marked hypoechogenicity (87.5%), and posterior shadowing (62.5%). CONCLUSIONS: DMP was more common in patients with longstanding DM; in particular, type 2 DM and insulin-dependent patients. DMP lesions were usually occult on mammography, despite the relatively large size of DMP, which may help distinguish DMP from invasive cancer. Ultrasound detected several features that are also present in invasive cancer, making tissue sampling necessary to distinguish these.

The different faces of renal angiomyolipomas on radiologic imaging: a pictorial review.

Renal angiomyolipoma (AML) is an uncommon renal tumour, generally composed of mature adipose tissue, dysmorphic blood vessels and smooth muscle. Identification of intratumoral fat on unenhanced CT images is the most reliable finding for establishing the diagnosis of renal AML. However, AMLs sometimes exhibit atypical findings, including cystic as well as solid forms; some of these variants overlap with the appearance of other renal tumours. A rare type of AML, the epithelioid type, possesses malignant potential. The aim of this pictorial review is to gather the different imaging features of AMLs including the classic and fat-poor types, AMLs with epithelial cysts, epithelioid AML, AML associated with tuberous sclerosis, haemorrhagic AML and large AMLs mimicking retroperitoneal liposarcomas. The diagnostic clues that help to distinguish AMLs from other renal tumours are also described in the review.

MRI of placenta percreta: differentiation from other entities of placental adhesive disorder.

OBJECTIVES: To retrospectively review the MRI findings of placenta percreta and identify those helpful for differentiation from non-placenta percreta. MATERIALS AND METHODS: The MRI images of 21 patients with a preliminary diagnosis of placental adhesive disorder scanned between 2005 and 2014 were evaluated. Radiologists blinded to the final diagnosis evaluated six previously described MRI findings of placenta adhesive disorder. The sensitivity, specificity, accuracy, negative predictive value (NPV), and positive predictive value (PPV) of MRI for the diagnosis of placenta percreta were also calculated. RESULTS: The study included 12 cases of placenta percreta and 9 cases of non-placenta percreta. Invasion of placental tissue outside the uterus was found only in placenta percreta (p = 0.045; sensitivity 41.7 %; specificity 100 %). All placenta percreta cases also had a moderate to marked degree of heterogeneous placental signal intensity (p = 0.063; sensitivity 100 %; specificity 33.3 %). The size of the dark bands on T2-weighted imaging, and the presence of disorganized intra-placental vessels, showed no statistically significant difference between placenta percreta and non-placenta percreta. The sensitivity, specificity, NPV, PPV, and accuracy of MRI for detection of placenta percreta were 91.7, 44, 80, 68, and 71.4 %, respectively. CONCLUSIONS: MRI is recommended for the evaluation of placenta percreta, with the most specific signs including the invasion of placental tissue outside the uterus on B-FFE sequences, and consideration of the degree of placental signal heterogeneity. The size of the T2 dark band alone, or bizarre disorganized intra-placental vessels, did not correlate with the severity of invasion.