Interpretation of Enterography in Patients with Crohn’s Disease

Computed tomography enterography and magnetic resonance enterography are presently state-of-the-art radiological tests to examine the small bowel in patients with Crohn’s disease. This review provides up-todate practical knowledge, including high-quality exemplary figures, to make the interpretation of enterography examinations more accurate and clinically relevant for improved care of patients with Crohn’s disease, emphasizing the interpretation of magnetic resonance enterography. The interpretative tasks include the diagnosis of the disease (through differential diagnosis from other mimicking conditions); specific assessment of the inflammatory activity, disease extent, and complications; assessment of the overall disease severity; diagnosis of remission; and identification of comorbidities. A good understanding of the clinical context of the patient and efforts to achieve more standardized interpretation is critical for more effective and more precise delivery of information.

Multiphasic CT and MR Imaging Findings of an Isolated Transverse Colon Hemangioma

Colonic hemangiomas are rare benign mesenchymal tumors but can potentially cause a life-threatening bleeding. Although phlebolith on simple radiography or CT scan is a pathognomonic sign of colonic hemangioma, it may not be always present. With wider use of cross-sectional images, it is necessary to know the imaging findings of the colonic hemangiomas on multiphasic scan and MRI for the correct diagnosis and management of the disease.

FDG Uptakes at Unilateral Axillary and Supraclavicular Lymph Nodes and Deltoid Muscle on [18F] FDG PET/CT After COVID-19 Vaccination: A Potential Pitfall for Metastatic Lymph Nodes in Colon Cancer Patient

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the ongoing global pandemic. It can manifest a wide range of complications depending upon the severity of infection and comorbidities of the patient. Vaccines are very important measure to provide protection against COVID-19. We report a case of 73-year-old female who underwent [¹⁸F]F-2-fluoro-2-deoxyd-glucose (FDG) positron emission tomography/computed tomography (PET/CT) and contrast-enhanced CT for staging of her rectosigmoid colon cancer and was found to have hypermetabolic uptakes in the deltoid muscle of the left shoulder and hypermetabolic left axillary and supraclavicular lymph nodes due to adenovirus vectored vaccine (ChAdOx1 nCoV-19, AstraZeneca) administrated 18 days ago prior to PET/CT scan.

Primary Malignant Melanoma of the Small Bowel with Hepatic Metastasis: A Case Report

Primary intestinal melanoma is extremely rare, whereas metastatic melanoma of the small bowel is common. In this report, we present a rare case of primary small bowel melanoma with hepatic metastasis. A 51-yearold man presented with constipation and CT identified an ileal mass without bowel obstruction. CT and MRI revealed hepatic metastasis. Ileal mass was confirmed on laparotomy and histologically diagnosed as melanoma.

Granulocyte Colony-Stimulating Factor (G-CSF) Induced Aortitis: A Case Report with Literature Review

Granulocyte colony-stimulating factor (G-CSF) is widely used as a neutrophil supportive therapy in cancer chemotherapy. Recently, some cases of G-CSF-induced aortitis are reported. Our case patient is a 54-year-old female diagnosed with breast cancer and received adjuvant chemotherapy with prophylactic use of G-CSF. She developed G-CSF-induced aortitis 20 days after the use of G-CSF. The disease was diagnosed with serum markers and radiologic findings. Her symptoms and imaging findings were rapidly improved with high-dose steroid therapy. The rapid improvement of the disease implies that prompt diagnosis with treatment can prevent severe vascular complications.

Cystic Lymphangioma of the Ileum Causing Small Bowel Obstruction: A Case Report

Cystic lymphangioma is a rare benign tumor containing chylous or serous fluid. The occurrence of cystic lymphangioma in the small bowel is known to be extremely rare. We would like to report a case of cystic lymphangioma that occurred in the small bowel and caused small bowel obstruction.

Determination of Gallstone Composition using Dual-Energy Computed Tomography: An Ex-vivo Study

Purpose: This study aimed to investigate whether ex-vivo gallstones are distinguishable by type using dualenergy computed tomography (DECT).Materials and Methods: A total of 124 gallstones from 65 patients with acute or chronic calculous cholecystitis were evaluated using DECT. The extracted gallstones were submerged in distilled water in an acrylic container and scanned at tube voltages of 80/140 kVp and 100/140 kVp. The images were grouped into three sets: 80, 100, and 140 kVp. Qualitative analyses of DECT sensitivity and attenuation patterns in each image set were performed, and quantitative analyses included calculation of mean attenuation values and measurement of the gallstone size. Semi-quantitative Fourier transform infrared (FTIR) spectroscopy was used as the reference standard to confirm the chemical composition of the gallstones.Results: FTIR spectroscopy identified 66 gallstones from 33 patients as cholesterol gallstones and 58 gallstones from 32 patients as pigment gallstones. Qualitative analysis indicated that DECT sensitivity for cholesterol gallstones was greatest at 80 kVp. Most cholesterol gallstones (79%) showed low attenuation at 80 kVp and high attenuation (65%) at 140 kVp. Pigment gallstones demonstrated high attenuation at all image sets. On quantitative analysis, the mean calculated attenuation values of cholesterol gallstones were -17 ± 50 Hounsfield Units (HU), -5.1 ± 43 HU, and 19.2 ± 39 HU at 80, 100, and 140 kVp, respectively, and 342 ± 173 HU, 286 ± 116 HU, and 195 ± 91 HU, respectively, for pigment stones.Conclusions: Ex-vivo gallstones were distinguishable as cholesterol or pigment gallstones by using DECT.

Gadoxetic Acid-Enhanced and Diffusion-Weighted Magnetic Resonance Imaging of Histologically Defined Early Hepatocellular Carcinoma

Purpose: To describe the imaging features of histologically defined early hepatocellular carcinoma (eHCC) on gadoxetate disodium-enhanced MRI (EOB-MRI) and diffusion-weighted imaging (DWI).Materials and Methods: We enrolled 173 surgically confirmed eHCCs in 119 patients examined by preoperative EOB-MRI and DWI between January 2006 and September 2017. The imaging features of preoperatively detected eHCCs were retrospectively analyzed by two radiologists. The clinical and imaging characteristics associated with false-negative detection were evaluated.Results: Of the 173 eHCCs, 118 (68%) in 78 patients were prospectively reported on preoperative EOB-MRI. After retrospective review, 17 eHCCs in 13 patients were additionally detected, with a per-lesion detection sensitivity of 78% (135/173). Thus, the imaging features of 135 eHCCs in 91 patients were analyzed. Most eHCCs exhibited hepatobiliary hypointensity (90%, 122/135). Arterial phase hyperenhancement, washout, and capsule appearance were seen in 68 (50%), 79 (59%), and 11 (8%) detected lesions, respectively. Diffusion restriction and fatty change were noted in 30 (22%) and 39 (29%) lesions, respectively; most eHCCs exhibited T1 and T2 isointensity (80 [59%] and 89 [66%], respectively). False-negative detection was associated with small lesion size (< 1 cm), history of HCC treatment (odds ratio, 0.34 [95% confidence interval, 0.13-0.92]), number of HCC lesions (≥ 2; odds ratio, 0.08 [0.01-0.66]), and poor functional liver imaging score (< 4; odds ratio, 0.13 [0.04-0.51]).Conclusions: Histologically defined eHCCs typically appear as hepatobiliary phase hypointensity. Detection sensitivity of eHCC may be affected by lesion size, history of HCC treatment, number of HCCs, and hepatobiliary enhancement.

Effect of Different Iterative Reconstruction Algorithms on Ultra-Low Dose CT of Inflammatory Bowel Disease in a Rabbit Model

Purpose: To evaluate the feasibility of ultra-low dose 80 kVp CT for the evaluation of inflammatory bowel disease (IBD) in a rabbit model and to investigate the effect of two different iterative reconstruction (IR) algorithms on 80 kVp CT in terms of image quality and diagnostic performance in comparison with same session conventional 120 kVp images.Materials and Methods: This study was approved by the Animal Care and Use Committee of our hospital. Twenty-eight New Zealand white rabbits were randomly divided into two groups: IBD group (n=18) and a control group (n=10). To create an acute IBD model, 3mL of a 5% w/v tri-nitrobenzene sulfonic acid solution was administered to the sigmoid colon of the rabbits. CT was performed at 80 kVp and 120 kVp and was reconstructed using filtered back projection (FBP), hybrid statistic-based IR, and full IR algorithms for 80 kVp and using FBP only for 120 kVp. Effective radiation dose, image noise, image quality, and diagnostic performance by two reviewers were recorded and compared using repeated measure analysis of variance, McNemar test, and receiver operating curve (ROC) analysis.Results: Mean effective radiation dose of 80 kVp CT (0.05 mSv) was significantly lower than that (0.285 mSv) of 120 kVp CT. Mean image noise was highest in the 80 kVp FBP setting (60.36) but significantly decreased with IR algorithms (47.02 with hybrid IR and 12.92 with full IR) (P<0.0001). Mean overall image quality score was lowest in the 80 kVp FBP setting (1.57 and 1.46 for reviewers 1 and 2, respectively) but significantly improved with IR algorithms (2.43 and 2.25 for hybrid IR and 4.79 and 4.93 for full IR) (P<0.0001). Sensitivity and area under the curve (AUC) for differentiating a normal bowel from IBD was lowest with 80 kVp FBP (61.1% and 83.3%; 0.883 and 0.967) but improved with IR algorithms (83.3%~100%; 0.992~1), to similar levels as the 120 kVp FBP setting (100% and 1). Differences in sensitivity and AUC between 80 kVp FBP and 80 kVp IR algorithms were statistically significant in reviewer 1.Conclusions: Ultra-low dose 80 kVp CT in a rabbit IBD model is not feasible using the standard FBP algorithm. However, with the application of IR algorithms, diagnostic performance of 80 kVp CT was acceptable and on par with that at conventional 120 kVp FBP.

Malignant Solitary Fibrous Tumor of Ileum with Intussusception

Solitary fibrous tumor (SFT) is rare mesenchymal neoplasm of fibroblastic or myofibroblastic origin. Especially, extrapleural SFT is known to be extremely rare. Here, we report a case of malignant SFT of ileum, resulting in small bowel intussusception in a 74-year-old female patient.