Utilization of virtual low-keV monoenergetic images generated using dual-layer spectral detector computed tomography for the assessment of peritoneal seeding from ovarian cancer.

This study aimed to compare the quality of virtual low-keV monoenergetic images vs conventional images reconstructed from dual-layer spectral detector computed tomography (SDCT) for the detection of peritoneal implants of ovarian cancer.Fifty ovarian cancer patients who underwent abdominopelvic SDCT scans were included in this retrospective study. Virtual monoenergetic images at 40 (VMI40) and 50 keV (VMI50), and two conventional images were reconstructed using filtered back projection (FBP) and iterative model reconstruction (IMR) protocols. The mean attenuation of the peritoneal implant, signal-to-noise ratio (SNR), contrast-to-noise ratio relative to ascites (CNRA) and adjacent reference tissues (e.g., bowel wall, hepatic, or splenic parenchyma [CNRB]) were calculated and compared using paired t tests. Qualitative image analysis regarding overall image quality, image noise, image blurring, lesion conspicuity, was performed by two radiologists. A subgroup analysis according to the peritoneal implant region was also conducted.VMI40 yielded significantly higher mean attenuation (183.35) of SNR and CNR values (SNR 11.69, CNRA 7.39, CNRB 2.68), compared to VMI50, IR, and FBP images (P < .001). The mean attenuation (129.65), SNR and CNR values (SNR 9.37, CNRA 5.72, CNRB 2.02) of VMI50 were also significantly higher than those of IR and FBP images (P < .001). In the subgroup analysis, all values were significantly higher on VMI40 regardless of the peritoneal implant region (P < .05). In both readers, overall image quality and image blurring showed highest score in VMI50, while image noise and lesion conspicuity showed best score in IMR and VMI40 respectively. Inter-reader agreements are moderate to almost perfect in every parameter.The low-keV VMIs improved both quantitative assessment and lesion conspicuity of peritoneal implants from ovarian cancer compared to conventional images.

Intravoxel incoherent motion MRI-derived parameters and T2* relaxation time for noninvasive assessment of renal fibrosis: An experimental study in a rabbit model of unilateral ureter obstruction.

PURPOSE: To evaluate the association of apparent diffusion coefficient (ADC), intravoxel incoherent motion (IVIM) MRI-derived parameters, and T2* relaxation time with histopathological changes observed during renal fibrogenesis in a rabbit model of unilateral ureter obstruction (UUO). METHODS: Twenty New Zealand White rabbits underwent baseline MRI followed by surgery (sham or UUO) and then follow-up MRI at postoperative day (POD) 0, 3, 7, and 14. Hematoxylin and eosin and Masson's trichrome staining was performed to evaluate cell density and area of fibrosis. Spearman rank correlation and Pearson correlation tests and one-way analysis of variance were used for statistical analyses. RESULTS: There was a continuous increase in the area of fibrosis and cell density: rho = 0.900 (95% confidence interval [CI] = 0.760, 0.960; p < 0.0001) and 0.904 (95% CI = 0.769, 0.962; p < 0.0001), respectively. There was a tendency for all MRI variables to decrease at POD 3 and partly recover at POD 7. ADC, D, f, and T2* relaxation time showed significant correlation with area of fibrosis and cell density (r = -0.5177 and -0.6962, -0.5395 and -0.7851, -0.7168 and -0.7902, and -0.6808 and -0.7212, respectively; p = 0.0052-0.0481) while D* did not (p = 0.1997 and 0.7853, respectively). CONCLUSIONS: ADC, IVIM MRI-derived parameters, and T2* relaxation time were significantly associated with the area of fibrosis and cell density during renal fibrogenesis in a rabbit model of UUO. After validation in future studies, MRI may have potential for noninvasive assessment modality of renal fibrosis.

Assessment of deep myometrial invasion of endometrial cancer on MRI: added value of second-opinion interpretations by radiologists subspecialized in gynaecologic oncology.

OBJECTIVE: To investigate the added value of secondary reports issued by radiologists subspecializing in gynaecologic imaging for determining deep myometrial invasion of endometrial cancer on MRI. METHODS: Initial (from referring institutions) and secondary (by subspecialized radiologists) interpretations of MRI of 55 patients with endometrial cancer were retrospectively reviewed. A radiologist blinded to clinicopathological information assessed both reports for the presence of deep myometrial invasion. Reference standard was based on hysterectomy specimens. Kappa coefficients (k) were used to measure their concordance. McNemar testing and receiver operating characteristic (ROC) analysis was used to compare sensitivities, specificities and areas under the curves (AUCs). RESULTS: Deep myometrial invasion was present in 25 (45.5 %) patients. Among 27.3 % (15/55; k = 0.458) patients with discrepant results, secondary interpretations were correct in 10 (66.7 %) cases. Sensitivity was higher in secondary than in initial reports (76.0 % vs. 48.0 %, p = 0.039) while no significant difference was seen in specificity (70.0 % vs. 76.7 %, p = 0.668). At ROC analysis, there was a tendency for higher AUCs in secondary reports (0.785 vs 0.669, p = 0.096). CONCLUSION: Secondary readings of MRI by subspecialized gynaecologic oncologic radiologists may provide incremental value in determining deep myometrial invasion of endometrial cancer. KEY POINTS: • Deep myometrial invasion is an important prognostic factor in endometrial cancer. • Assessment of deep myometrial invasion is often discrepant between initial and secondary reports. • Secondary reports showed higher sensitivity and accuracy. • Secondary review of MRI may provide incremental value in endometrial cancer patients.

Shear wave elastography assessment in the prostate: an intraobserver reproducibility study.

PURPOSE: To assess the intraobserver reproducibility of shear wave elastography (SWE) in the prostate. MATERIALS AND METHODS: This study was institutional review board approved with waiver of informed consent. Eighty men (mean age, 66.2±9.2years) with suspected prostate cancer underwent SWE. Young modulus (kPa) was measured at 24 locations in the prostate (superficial and deep locations in paramedian and lateral aspects at the base, mid-gland, and apex levels). The intraobserver reproducibility of two repeated measurements was determined using intraclass correlation coefficients (ICC) and was compared among measurement location, prostate volume, age, and prostate-specific antigen level. RESULTS: The overall intraobserver reproducibility was excellent (ICC=0.876). In addition, intraobserver reproducibility was excellent for all specified subgroups according to location, prostate volume, and clinical variables (ICC=0.826-0.917). With regard to location, SWE measurements showed substantially higher ICC values in the mid-gland than in the base and apex, in the paramedian prostate than in the lateral prostate, and in superficial locations than in deeper locations. No substantial differences in ICC values were observed according to the prostate volume and clinical variables. CONCLUSION: Intraobserver reproducibility of SWE measurements in the prostate gland was excellent. There was variability in the intraobserver reproducibility according to location within the prostate, and the operator should be aware of this and take extra caution when performing SWE in these areas.

Assessment of cystic renal masses based on Bosniak classification: comparison of CT and contrast-enhanced US.

OBJECTIVES: To compare retrospectively the imaging features of computed tomography (CT) and contrast-enhanced US (CEUS) imaging for the assessment of cystic renal masses using the Bosniak classification system. MATERIALS AND METHODS: The CT and CEUS images of 31 pathologically confirmed cystic renal masses in 31 patients were retrospectively analyzed for septa numbers, wall and/or septa thickness, enhancement degree, and for the presence of a solid component by consensus between two radiologists using the Bosniak classification. Diagnostic accuracies of CT and CEUS for malignant cystic tumor were calculated and compared using McNemar test. RESULTS: Diagnostic accuracies of CT and CEUS for malignant renal tumor were 74% and 90%, respectively, but there were not statistically different (P>0.05). CEUS and CT images showed same Bosniak classification in 23 (74%) lesions and there were differences in 8 (26%) lesions, all of which were upgraded by CEUS; one lesion from I to IV, two lesions from II to IV, two lesions from IIF to III, and three lesions from III to IV. CEUS images depicted more septa in 10 (32%) lesions, more thickened wall and/or septa in 4 (13%) lesions, and stronger enhancement in 19 (61%) lesions. Moreover, for six lesions, solid component was detected by CEUS but not by CT. CONCLUSION: CEUS might better visualize septa number, septa and/or wall thickness, solid component and the enhancement of some renal cystic masses than CT, resulting in upgrade of Bosniak classification and affecting their treatment plan.