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Objectives: The objective of this study was to find the diagnostic values of additional ultrasound (US) in patients with equivocal computed tomography (CT) findings of acute appendicitis, compared to CT reassessment. Materials and Methods: Patients with equivocal CT findings of acute appendicitis (n = 115), who underwent the US, were included in the study. Two abdominal radiologists reviewed CT scans independently. They analyzed CT findings and made a diagnosis of acute appendicitis. The patients were categorized into positive and negative appendicitis based on the previous US reports. The diagnostic performance, interobserver agreement of CT findings, and appendicitis likelihood were calculated. Results: The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of US (100%, 92.1%, 79.5%, and 100%, respectively) were higher than those of CT reassessment (reviewer 1: 51.9%, 87.5%, 56.1%, and 85.6%; reviewer 2: 66.7%, 85.2%, 58.1%, and 89.3%, respectively). In the coexistent inflammation group, the sensitivity, specificity, PPV, and NPV of US (reviewer 1: 100%, 98%, 91.5%, and 100%; reviewer 2: 100%, 98%, 87.7%, and 100%, respectively) were higher than those of CT reassessment (reviewer 1: 27.3%, 94.1%, 49.9%, and 85.8%; reviewer 2: 14.3%, 98.0%, 50.5%, and 88.9%, respectively). Conclusion: In patients with equivocal CT findings of acute appendicitis, US shows better diagnostic performance than CT reassessment, and helps differentiate with periappendicitis.

Hepatic pseudolymphoma is a rare benign liver mass that is characterized by proliferation of non-neoplastic lymphocytes extranodally. To the best of our knowledge, only 46 cases have been reported in the English literature. We described the case of a 75-year-old woman with hepatic pseudolymphoma mimicking a hypervascular tumor. After the histological confirmation of the rectal neuroendocrine tumor, CT scan revealed a 1.0 cm-sized, poorly-defined and low-density nodule in the liver. On MRI, the hepatic nodule showed an arterial enhancement and a low-signal intensity on the hepatobiliary phase. On diffusion-weighted imaging, the hepatic nodule showed a high signal intensity on a high b-value. On fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT, it revealed a high standardized uptake value nodule. The US showed the hypoechoic nodule and the US-guided biopsy confirmed the hepatic pseudolymphoma.

We report the sonographic features of confirmed malignant appendiceal tumors in seven cases. The histologic diagnoses of these tumors were mucinous cystadenocarcinoma (n = 2), colonic type adenocarcinoma (n = 4), and signet-ring cell carcinoma (n = 1). The 2 mucinous cystadenocarcinomas showed mucocele type, which had markedly enlarged inner luminal diameters (mean, 23 mm; range, 15–31 mm) and thick, irregular walls (mean wall thickness, 5.5 mm; range, 5–6 mm). In contrast, the 5 nonmucinous carcinomas (4 adenocarcinomas and 1 signet-ring cell carcinoma) showed nonmucocele type, which had relatively small inner luminal diameters (mean ± standard deviation [SD], 6.6 ± 4.5 mm; range, 2–15 mm) and prominent wall thickening (mean wall thickness ± SD, 6.2 ± 2.3 mm; range, 3–10 mm). Of the 5 nonmucinous tumors, only one had a discernible mass, three had thick irregular walls, two had loss of the wall layer pattern, and four had submucosal hypoechogenicity. Regardless of the histologic type, five of the seven malignant appendiceal tumors showed a severe periappendiceal fat infiltration or periappendiceal abscess, suggestive of perforation. Although the sonographic findings of the malignant appendiceal tumors were nonspecific, some of the sonographic features seen in these seven cases may help radiologists consider the possibility of underlying malignant appendiceal tumors.

Summary Background CT radiation is arguably carcinogenic. Results from single-centre studies, mostly retrospective, have advocated lowering the CT radiation dose for the diagnosis of appendicitis. However, adoption of low-dose CT has been slow. We aimed to assess the effectiveness of low-dose CT compared with standard-dose CT in the diagnosis of appendicitis in adolescents and young adults. Methods We did this pragmatic, multicentre, randomi s ed controlled non-inferiority trial at 20 South Korean teaching hospitals with little experience with low-dose CT. Patients aged 15–44 years with suspected appendicitis were randomly assigned (1:1), via computer-generated random assignments (permuted block sizes of two, four, six, and eight) concealed in sequentially numbered envelopes, to receive low-dose CT (2 mSv) or standard-dose CT (≤8 mSv). Randomisation was stratified by site. Group allocation was concealed from patients, outcome assessors, and adverse event adjudicators; care providers, site pathologists, and data collectors were aware of allocation. The primary endpoint was the negative (unnecessary) appendectomy rate among all appendectomies, with a non-interiority margin of 4·5% for low-dose versus standard-dose CT. Primary analy s is was by modified intention to treat, which included all patients who received an appendectomy in the group to which they were assigned. This trial is registered with ClinicalTrials.gov, number NCT01925014. Findings Between Dec 4, 2013, and Aug 18, 2016, we assigned 1535 patients to the low-dose CT group and 1539 patients to the standard-dose CT group. 22 (3·9%) of 559 patients had a negative appendectomy in the low-dose group versus 16 (2·7%) of 601 patients in the standard-dose group (difference 1·3%, 95% CI −0·8 to 3·3; p=0·0022 for the non-inferiority test). We recorded 43 adverse events in 43 (2·8%) of 1535 patients in the low-dose group and 41 adverse events in 40 (2·6%) of 1539 patients in the standard-dose group. One life-threatening adverse event of anaphylaxis caused by an iodinated contrast material occurred in the low-dose group. Interpretation Radiation dose of appendiceal CT for adolescents and young adults can be reduced to 2 mSv without impairing clinical outcomes. In view of the vast number of appendiceal CT examinations done worldwide, use of low-dose CT could prevent a sizeable number of radiation-associated cancers in the future. Funding Korea Health Industry Development Institute, Seoul National University Bundang Hospital, Dasol Life Science, and Bracco Imaging Korea.

To identify the features that can be used for differentiating appendicitis from non-appendicitis in pediatric patients with equivocal ultrasound (US) results.A total of 53 pediatric patients (≤ 18 years old) with equivocal results on US examination for suspected appendicitis between November 2012 and October 2017 were included. US evaluation was conducted based on information retrieved from a predefined structured report form. Then, the likelihood of appendicitis was prospectively classified into five categories. The equivocal results were considered as grade 3 (indeterminate) and grade 4 (probably appendicitis).Of the 53 patients, 25 (47.2%) and 28 (52.8%) were classified into grade 3 and 4 groups, respectively. Among the individual US findings, increased vascularity of the appendiceal wall and peri-appendiceal fat infiltration were independent findings associated with the diagnosis of appendicitis (Increased vascularity within the appendiceal wall and peri-appendiceal fat infiltration were significant predictors of appendicitis in patients with equivocal US findings.애매한 초음파 결과를 보인 소아 환자들에서 충수돌기염을 감별하는 데 도움이 되는 초음파 소견들을 알아보고자 한다.2012년 11월부터 2017년 10월 사이에 충수돌기염이 의심되어 초음파를 시행한 소아 환자 중 애매한 결과를 보인 53명의 환자를 대상으로 하였다. 초음파 검사는 정해진 구조화 판독문을 사용했으며 충수돌기염의 가능성은 5가지로 분류되었다. 그중 3등급과 4등급을 애매한 결과로 간주하였다.53명의 환자 중 각각 25명(47.2%)과 28명(52.8%)이 3등급과 4등급으로 분류되었다. 각 초음파 소견 중 충수돌기 벽의 혈류 증가와 충수돌기 주변의 지방 침윤이 충수돌기염을 진단하는 데 다변량 로지스틱 회귀분석에서 의미 있는 소견이었고(충수돌기 벽의 혈류 증가와 충수돌기 주변의 지방 침윤은 애매한 초음파 결과를 보인 소아 환자들에서 의미 있는 충수돌기염의 예견 인자이다.

Mucosa-associated lymphoid tissue (MALT) lymphomas are an extranodal subset of marginal zone B-cell lymphomas and represent > 8% of all types of lymphomas (1). In 1983, Isaacson and Wright (2) initially described MALT lymphomas as a distinctive type of B-cell lymphoma arising in the gastrointestinal tract. MALT lymphomas can be found at mucosal sites such as the stomach, lung, and salivary gland or from sites, which share an embryologic origin with mucosa such as the thyroid that normally lacks organized lymphoid tissue (3). Primary hepatic MALT lymphoma is an extremely rare lesion, with only 45 cases reported in the English literature (4, 5). Because of its rarity, the radiologic findings in patients with this lesion are seldom described, to our best knowledge. Herein, we reported a patient with pathologically proven primary MALT lymphoma who underwent ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), and fluorodeoxyglucose positron emission tomography with CT (FDG PET/CT).

In this report, we present a rare case of primary signet-ring cell carcinoma of the appendix in a 51-year-old woman with right lower quadrant pain. Since non-specific concentric appendiceal wall thickening was found in a radiologic evaluation, it was misdiagnosed as non-tumorous appendicitis. An in-depth examination of the correlation between sonographic and histopathologic findings demonstrated that a single markedly thickened hypoechoic layer was well correlated with the diffuse infiltration of tumor cells in both the submucosal and muscle layers. If this sonographic finding is observed in certain clinical settings, such as potential ovarian and peritoneal metastasis, submucosal infiltrative tumors, including signet-ring cell carcinoma, should be considered in the differential diagnosis.

The purpose of this study was to retrospectively assess CT predictors of unfavorable outcomes of medical treatment in patients with right colonic diverticulitis.Of 394 patients with right colonic diverticulitis diagnosed on the basis of CT findings from January 2010 through August 2013, we included 328 (190 men, 138 women; mean age, 41.3 ± 12.6 years) who had undergone medical treatment as inpatients. Two radiologists retrospectively reviewed the following CT findings associated with diverticulitis: number of diverticula per 10 cm of colon; length and thickness of affected colonic wall; diameter of inflamed diverticulum and abscess; presence of pericolic fluid collection, spilled feces, and contained air; and extent of fatty infiltration. Logistic regression analysis and the Cox proportional hazards regression model were used to determine significant variables predictive of unfavorable outcomes, including surgery after failed medical treatment, recurrence, and prolonged hospital stay.Of the 328 patients, nine underwent surgery after failed medical treatment. Of the other 319 patients, 35 had recurrence and 49 had a prolonged hospital stay. The spilled feces sign (adjusted odds ratio [OR], 111; p0.001) and serum WBC count (adjusted OR, 1.3; p = 0.047) were independent predictors of the need for surgery. More than five multiple diverticula per 10 cm of colon was significantly associated with recurrence (adjusted hazard ratio, 4.1; p0.001). Abscess larger than 4 cm (adjusted OR, 18.2; p = 0.01) and inflamed diverticulum larger than 2 cm (adjusted OR, 3.7; p = 0.001) were independent predictors of prolonged hospital stay.Some specific CT findings can be useful predictors of unfavorable clinical outcomes of right colonic diverticulitis.

To investigate CT features and differential diagnosis of pancreatic adenocarcinoma compared to other solid tumours arising in the periampullary area. One hundred and ninety-five patients with pathologically proven, solid periampullary tumours, including pancreatic adenocarcinoma (n = 98), neuroendocrine tumours (n = 52), gastrointestinal stromal tumours (n = 31), and solid pseudopapillary neoplasms (n = 14), underwent preoperative CT. Two radiologists reviewed CT features and rated the possibility of pancreatic adenocarcinoma. Statistically common findings for pancreatic adenocarcinoma included: patient age >50 years; ill-defined margin; completely solid mass; homogeneous enhancement; hypoenhancement on arterial and venous phases; atrophy; and duct dilatation. Statistically common findings for GIST included: heterogeneous enhancement; hyperenhancement on arterial and venous phases; rim enhancement; and prominent feeding arteries. The hyperenhancement on arterial and venous phases is statistically common in NET, and heterogeneous enhancement, hypoenhancement on the arterial and venous phases are statistically common in SPN. Diagnostic performance of CT for differentiating pancreatic adenocarcinomas from other solid periampullary tumours was 0.962 and 0.977 with excellent interobserver agreement (κ = 0.824). CT is useful not only for differentiating pancreatic adenocarcinoma form other solid tumours but also for differentiating between other solid tumours, including NET, SPN, and GIST, arising in the periampullary area. • Periampullary tumours arise within 2 cm of major duodenal papilla. • Many mass-forming periampullary tumours can be completely removed by minimal surgery. • Accurate differentiation of pancreatic adenocarcinoma from other solid tumours is important. • CT is useful for differentiating pancreatic adenocarcinoma from other solid tumours. • CT is useful for characterization of periampullary tumours other than adenocarcinomas.

To compare magnetic resonance (MR) elastography and ultrasonographic shear-wave elastography ( SWE shear-wave elastography ) for the staging of hepatic fibrosis ( HF hepatic fibrosis ) in the same individuals.This prospective study was approved by the institutional review board, and informed consent was obtained from all patients. The technical success of and reliable liver stiffness ( LS liver stiffness ) measurement rates at MR elastography and SWE shear-wave elastography were compared in 129 patients who underwent both examinations. For mutual validation, LS liver stiffness values measured at both examinations were correlated by using Pearson correlation. The diagnostic performance of the two techniques for the assessment of substantial HF hepatic fibrosis (stage ≥ F2) was compared by using nonparametric receiver operating characteristic analysis.The technical success rates of MR elastography and SWE shear-wave elastography were 95.35% (123 of 129) and 97.67% (126 of 129), respectively (P = .51). MR elastography provided significantly more reliable LS liver stiffness measurements than did SWE shear-wave elastography (95.35% [123 of 129] vs 75.2% [97 of 129], P.001). The two examinations showed moderate correlation (r = 0.724). In patients with HF hepatic fibrosis stages of F3 or lower, the two examinations showed moderate-to-strong correlation (r = 0.683 in normal livers, 0.754 in livers with stage F0 or F1 HF hepatic fibrosis , and 0.90 in livers with stage F2 or F3 HF hepatic fibrosis ; P.001); however, they did not show significant correlation for stage F4 HF hepatic fibrosis (r = 0.30, P = .31). MR elastography and SWE shear-wave elastography showed similar diagnostic capability in depicting HF hepatic fibrosis of stage F2 or greater (P = .98) when LS liver stiffness measurements were reliably performed.MR elastography and SWE shear-wave elastography showed moderate correlation and similar diagnostic performance in the diagnosis of HF hepatic fibrosis of stage F2 or greater; however, MR elastography yielded more reliable LS liver stiffness measurements than did SWE shear-wave elastography .

Solid tumors of the pancreas can have a broad spectrum of diseases (Table 20.1). Most pancreatic solid tumors are ductal adenocarcinomas. Each of the other tumors comprises only a small portion of the total number of pancreatic solid tumors, although as these tumors include some of the most treatable pancreatic tumors, their correct diagnosis is extremely important.

Supradiaphragmatic liver is a rare condition. Establishing an accurate preoperative diagnosis is difficult. Operative exploration is necessary to differentiate this lesion from intrathoracic masses, such as a pleural based tumor, diaphragmatic tumor and peripheral lung tumor. However, with the aid of the hepatocyte-specific magnetic resonance imaging contrast agent, gadoxetic acid (Gd-EOB-DTPA), functional hepatocytes in the lesion can be identified in the hepatobiliary phase, potentially allowing an accurate and non-invasive diagnosis. We report a case of supradiaphragmatic liver diagnosed by GdEOB-DTPA-enhanced magnetic resonance imaging.

Extrapulmonary small cell carcinoma is a rare neoplasm. It is a highly aggressive, malignant tumor with rapid local progression and early metastasis. We report a case of small cell carcinoma arising in the rectum that presented as a bowel habit change in a 57-year-old man. Physical examination revealed a firm, fixed mass in the rectum. Computed tomography of the mass revealed a circumferential bulky mass with an irregular margin with perirectal fat infiltration and enlarged regional lymph nodes. Histologic examination of the resected mass was consistent with small cell carcinoma of the rectum.

A primary mucosa-associated lymphoid tissue lymphoma (MALT lymphoma) of the breast is extremely rare. We report a case of a MALT lymphoma of the breast that presented as a palpable left breast mass in a 37-year-old woman. A physical examination revealed a large firm, and fixed mass in the left inner breast. Mammograms showed a large, isodense mass in the lower inner quadrant of the left breast and an enlarged lymph node in the axilla. A sonogram demonstrated a 5 cm sized, oval, circumscribed, and heterogeneously hypoechoic mass with posterior acoustic enhancement. A surgical biopsy was performed, and the pathology revealed a MALT lymphoma.

A malignant fibrous histiocytoma of the mesentery is rare, and multifocal involvement as a primary tumor is very rare. In this report, a case of malignant fibrous histiocytoma of the mesentery presenting with two masses and multiple peritoneal seeding in a 48-year-old man is described. A physical examination revealed a large, firm, and non-tender mass in the right lower abdomen of the patient. Computed tomography of the lesion revealed a partially, indistinctly marginated and heterogeneously enhancing mass with irregular peritumoral strands in the mesentery of the right lower abdomen, while sonograms of the lesion revealed an ill-defined low-echoic mass. The final pathology demonstrated the presence of a storiform-pleomorphic malignant fibrous histiocytoma.