Image Quality and Lesion Detectability of Lower-Dose Abdominopelvic CT Obtained Using Deep Learning Image Reconstruction

Objective@#To evaluate the image quality and lesion detectability of lower-dose CT (LDCT) of the abdomen and pelvis obtained using a deep learning image reconstruction (DLIR) algorithm compared with those of standard-dose CT (SDCT) images. @*Materials and Methods@#This retrospective study included 123 patients (mean age ± standard deviation, 63 ± 11 years;male:female, 70:53) who underwent contrast-enhanced abdominopelvic LDCT between May and August 2020 and had prior SDCT obtained using the same CT scanner within a year. LDCT images were reconstructed with hybrid iterative reconstruction (h-IR) and DLIR at medium and high strengths (DLIR-M and DLIR-H), while SDCT images were reconstructed with h-IR. For quantitative image quality analysis, image noise, signal-to-noise ratio, and contrast-to-noise ratio were measured in the liver, muscle, and aorta. Among the three different LDCT reconstruction algorithms, the one showing the smallest difference in quantitative parameters from those of SDCT images was selected for qualitative image quality analysis and lesion detectability evaluation. For qualitative analysis, overall image quality, image noise, image sharpness, image texture, and lesion conspicuity were graded using a 5-point scale by two radiologists. Observer performance in focal liver lesion detection was evaluated by comparing the jackknife free-response receiver operating characteristic figures-of-merit (FOM). @*Results@#LDCT (35.1% dose reduction compared with SDCT) images obtained using DLIR-M showed similar quantitative measures to those of SDCT with h-IR images. All qualitative parameters of LDCT with DLIR-M images but image texture were similar to or significantly better than those of SDCT with h-IR images. The lesion detectability on LDCT with DLIR-M images was not significantly different from that of SDCT with h-IR images (reader-averaged FOM, 0.887 vs. 0.874, respectively; p = 0.581). @*Conclusion@#Overall image quality and detectability of focal liver lesions is preserved in contrast-enhanced abdominopelvic LDCT obtained with DLIR-M relative to those in SDCT with h-IR.

Gant Infrascapular Rheumatoid Nodules Mimicking Elastofibroma Dorsi:A Case Report

Rheumatoid nodules are the most common extra-articular presentations of rheumatoid arthritis. Although rheumatoid nodules can develop anywhere in the body, they develop most commonly in the subcutaneous region, where they are easily exposed to repetitive trauma or pressure. However, an infrascapular presentation has not yet been reported. We report a case of giant bilateral rheumatoid nodules that developed in the infrascapular area, complicating its distinction from elastofibroma dorsi on radiological examination.

A Case Report of Cholangiocarcinoma Arising from a Biliary Adenofibroma:Radiologic Findings and Review of Literature

Biliary adenofibromas are rare biliary epithelial tumors that are classified as benign. Nevertheless, some cases have been reported to show malignant transformations. The radiologic findings of biliary adenofibromas and their malignant transformation are not well-established because of their rarity. We present a case of a cholangiocarcinoma arising from a biliary adenofibroma assessed using ultrasonography, CT, and MRI. The differential diagnoses include other hepatic tumors.

A Case Report of Cholangiocarcinoma Arising from a Biliary Adenofibroma:Radiologic Findings and Review of Literature

Biliary adenofibromas are rare biliary epithelial tumors that are classified as benign. Nevertheless, some cases have been reported to show malignant transformations. The radiologic findings of biliary adenofibromas and their malignant transformation are not well-established because of their rarity. We present a case of a cholangiocarcinoma arising from a biliary adenofibroma assessed using ultrasonography, CT, and MRI. The differential diagnoses include other hepatic tumors.

Diffuse Large B-Cell Lymphoma in the Portal Vein

Tumor thrombus in the portal vein without any liver parenchymal abnormality is extremely rare. In the liver, the primary tumor most frequently presenting with intravascular tumor thrombi is hepatocellular carcinoma and lymphoma is rarely considered. Even though thrombosis occurs quite often in lymphoma, cases of tumor thrombus are rare and cases of tumor thrombus in the portal vein are even rarer. Only four cases of lymphoma with portal vein tumor thrombosis have been reported to date and all cases were the result of direct extensions of a dominant nodal or extra-nodal mass. To our knowledge, there has been no report on diffuse large B-cell lymphoma (DLBCL) presenting only within the lumen of the portal vein and not intravascular B-cell lymphoma. We present the first case of DLBCL presenting only within the lumen of the portal vein in an immunocompetent patient.

Dynamic Contrast-Enhanced Magnetic Resonance Imaging as a Surrogate Biomarker for Bevacizumab in Colorectal Cancer Liver Metastasis: A Single-Arm, Exploratory Trial / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: The purpose of this study is to investigate dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and plasma cytokines and angiogenic factors (CAFs) as pharmacodynamic and prognostic biomarkers of bevacizumab monotherapy in colorectal cancer with liver metastasis (CRCLM). MATERIALS AND METHODS: From July 2011 to March 2012, 28 patients with histologically confirmed CRCLM received bevacizumab monotherapy followed by combined FOLFOX therapy. The mean age of the patients was 57 years (range, 30 to 77 years). DCE-MRI (K(trans) and IAUC₆₀) was performed at baseline, first follow-up (3 days after bevacizumab monotherapy), and second follow-up (3 days after combined therapy). CAF levels (vascular endothelial growth factor [VEGF], placental growth factor [PlGF], and interleukin-8) were assessed on the same days. Progression-free survival (PFS) time distributions were summarized using the Kaplan-Meier method and compared using log-rank tests. RESULTS: The median PFS period was 11.2 months. K(trans), IAUC₆₀, VEGF, and PlGF values on the first follow-up day were significantly different compared with baseline values. No differences were observed on the second follow-up day. A > 40% decrease in K(trans) from baseline to first follow-up was associated with a longer PFS (hazard ratio, 0.349; 95% confidence interval, 0.133 to 0.912; p=0.032). Changes in CAFs did not show correlation with PFS time. CONCLUSION: DCE-MRI parameters and CAFs are pharmacodynamic biomarkers of bevacizumab for CRCLM. In our study, change in K(trans) at 3 days after bevacizumab monotherapy was a favorable prognostic factor; however, the value of CAFs as a prognostic biomarker was not found.

Hepatic Lymphoma Representing Iso-Signal Intensity on Hepatobiliary Phase, in Gd-EOB-DTPA-Enhanced MRI: Case Report

Image findings of hepatic lymphoma have been reported as variable, ranging from single or multiple small nodules to diffuse infiltrative patterns. On MRI, most hepatic lymphomas show T1 low signal intensity, T2 high signal intensity. Dynamic imaging reveals a hypointense appearance in the arterial phase, followed by delayed enhancement in the portal venous and transitional phase. In the hepatobiliary phase using a hepatocyte-specific contrast agent (which have recently aided in increasing the access to the focal liver lesions), hepatic lymphoma is known to exhibit low signal intensity. We report a case of hepatic lymphoma, which shows iso-signal intensity on hepatobiliary phase, using gadoxetic acid (Gd-EOB-DTPA).

Amyand Hernia: Sonographic and CT Appearances

Herniation of the appendix into an inguinal canal is known as an Amyand hernia. Due to its nonspecific symptoms, clinical diagnosis is extremely difficult, and an accurate preoperative diagnosis of Amyand hernia with ultrasound (US) and CT is rarely reported. Herein, we reported a typical case of Amyand hernia in a 74-year-old male in which the correct diagnosis was made using inguinal US and contrast-enhanced abdominopelvic CT. US and CT findings of Amyand hernia showed a target-like tubular structure within the inguinal canal.

Adrenal Mass as Initial Presentation of Metastatic Hepatocellular Carcinoma: A Case Report

Metastases from hepatocellular carcinoma (HCC) can be found in the multiple organs including adrenal gland. But adrenal metastasis of HCC without obvious hepatic lesion is very rare. We report CT and MR findings of a patient who presented with adrenal metastasis as the first clinical manifestation of HCC. Signal intensity and enhancement pattern of adrenal metastastic mass of HCC were similar to those of HCC on MRI.

Perfusion Parameters of Dynamic Contrast-Enhanced Magnetic Resonance Imaging in Patients with Rectal Cancer: Correlation with Microvascular Density and Vascular Endothelial Growth Factor Expression

OBJECTIVE: To determine whether quantitative perfusion parameters of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) correlate with immunohistochemical markers of angiogenesis in rectal cancer. MATERIALS AND METHODS: Preoperative DCE-MRI was performed in 63 patients with rectal adenocarcinoma. Transendothelial volume transfer (Ktrans) and fractional volume of the extravascular-extracellular space (Ve) were measured by Interactive Data Language software in rectal cancer. After surgery, microvessel density (MVD) and vascular endothelial growth factor (VEGF) expression scores were determined using immunohistochemical staining of rectal cancer specimens. Perfusion parameters (Ktrans, Ve) of DCE-MRI in rectal cancer were found to be correlated with MVD and VEGF expression scores by Spearman's rank coefficient analysis. T stage and N stage (negative or positive) were correlated with perfusion parameters and MVD. RESULTS: Significant correlation was not found between any DCE-MRI perfusion parameters and MVD (rs = -0.056 and p = 0.662 for Ktrans; rs = -0.103 and p = 0.416 for Ve), or between any DCE-MRI perfusion parameters and the VEGF expression score (rs = -0.042, p = 0.741 for Ktrans ; r = 0.086, p = 0.497 for Ve) in rectal cancer. TN stage showed no significant correlation with perfusion parameters or MVD (p > 0.05 for all). CONCLUSION: DCE-MRI perfusion parameters, Ktrans and Ve, correlated poorly with MVD and VEGF expression scores in rectal cancer, suggesting that these parameters do not simply denote static histological vascular properties.

Spontaneous Treatment of Renal Artery Pseudoaneurysm after Partial Nephrectomy: A Case Report

A partial nephrectomy is being used increasingly for the removal of renal cell carcinomas. A renal artery pseudoaneurysm (RAP) is a rare, potentially life threatening complication after a partial nephrectomy. This paper presents a case of spontaneous thrombosis of RAP after a partial nephrectomy. The presented case is believed to be the largest in diameter (59 mm) among the reported cases of spontaneous treatment of RAP by complete thrombosis.