Medical Devices of the Abdomen and Pelvis and Their Complications: A Radiologic Atlas

A variety of medical devices have evolved throughout the years. Commonly used devices have typical radiological appearances which are familiar to radiologists. However, some new devices, as well as devices that are not commonly used, may be missed or misinterpreted by radiologists. It is even more difficult to identify a certain medical device with limited clinical history. Therefore, accurate identification of medical devices is crucial to diagnose malposition and potential complications. In this article, we provide a pictorial review of medical devices of the abdomen and pelvis according to classifications that include gastrointestinal devices, hepatobiliary devices, genitourinary devices, and miscellaneous. We also comprehensively review the clinical and radiologic features of complications related to these medical devices.

Undifferentiated Carcinoma with Osteoclast-Like Giant Cells of the Pancreas Mimicking a Predominantly Calcified Mass: Case Report and Literature Review

Undifferentiated carcinoma with osteoclast-like giant cells (UCOGCs) of the pancreas is a rare neoplasm that contains osteoclast-like giant cells, which are morphologically identical to those seen in giant cell tumors of bones. Histopathologically, it is composed of round to spindle-shaped neoplastic cells and non-neoplastic histiocytic giant cells. Although only limited radiologic findings are available due to the rarity of this tumor, UCOGCs shows variable imaging features in the literature from an inhomogeneous solid mass to a multilocular cystic tumor. Herein, we report an unusual manifestation of UCOGCs of the pancreas mimicking a predominantly calcified mass with radiologic-pathologic correlation.

Toxocariasis Mimicking Lymphoma and Presenting as Multiple Lymphadenopathy: A Case Report

Toxocariasis, a parasitic infection, causes hyper eosinophilia resulting in radiological presentation of eosinophilic infiltrations in the involved organs. In the abdomen, toxocariasis has been reported to manifest as infiltrations in the liver or in the gastrointestinal tract, but it is known to be uncommon to manifest as multiple lymphadenopathy. There have been two case reports of toxocariasis presenting as generalized lymphadenopathy in the chest, neck and inguinal regions. To the best of our knowledge, generalized conglomerated lymphadenopathy occurring mostly in the abdomen from toxocariasis has not been published in the English literature. Herein, we report a rare case of toxocariasis presenting as multiple conglomerated lymphadenopathy mimicking lymphoma on CT.

Correlation between Abdominal Fat Amount and Fatty Liver, using Liver to Kidney Echo Ratio on Ultrasound

PURPOSE: It has been generally recognized that fatty liver can often be seen in the obese population. This study was conducted in order to evaluate the association between fatty liver and abdominal fat volume. MATERIALS AND METHODS: A total of 105 patients who visited our obesity clinic in the recent three years underwent fat CT scans and abdominal US. Attenuation difference between liver and spleen on CT was considered as a reference standard for the diagnosis of fatty liver. On US, the echogenicity of the liver parenchyma was measured in three different regions of interest (ROI) close to the adjacent right kidney in the same slice, avoiding vessels, bile duct, and calcification. Similar measurements were performed in the right renal cortex. The mean values were calculated automatically on the histogram of the ROI using the PACS program. The hepatorenal echogenicity ratio (HER; mean hepatic echogenicity/mean renal echogenicity) was then calculated. Abdominal fat volume was measured using a 3 mm slice CT scan at the L4/5 level and was calculated automatically using a workstation. Abdominal fat was classified according to total fat (TF), visceral fat (VF), and subcutaneous fat (SF). We used Pearson's bivariate correlation method for assessment of the correlation between HER and TF, VF, and SF, respectively. RESULTS: Significant correlation was observed between HER and abdominal fat (TF, VF, and SF). HER showed significant correlation with VF and TF (r = 0.491 and 0.402, respectively; p = 0.000). The correlation between HER and SF (r = 0.255, p = 0.009) was less significant than for VF or TF. CONCLUSIONS: Fat measurement (HER) by hepatic ultrasound correlated well with the amount of abdominal fat. In particular, the VF was found to show a stronger association with fatty liver than SF.

Cystic Lesions of the Gastrointestinal Tract: Multimodality Imaging with Pathologic Correlations

The cystic lesions of the gastrointestinal (GI) tract demonstrate the various pathologic findings. Some lesions may present a diagnostic challenge because of non-specific imaging features; however, other lesions are easily diagnosed using characteristic radiologic features and anatomic locations. Cystic masses from the GI tract can be divided into several categories: congenital lesions, neoplastic lesions (cystic neoplasms, cystic degeneration of solid neoplasms), and other miscellaneous lesions. In this pictorial review, we describe the pathologic findings of various cystic lesions of the GI tract as well as the radiologic features of GI cystic lesions from several imaging modalities including a barium study, transabdominal ultrasound (US), computed tomography (CT), and magnetic resonance (MR) imaging.

Gadoxetic Acid (Gd-EOB-DTPA)-Enhanced MRI versus Gadobenate Dimeglumine (Gd-BOPTA)-Enhanced MRI for Preoperatively Detecting Hepatocellular Carcinoma: an Initial Experience

OBJECTIVE: This study was designed to compare the diagnostic performance of gadoxetic acid-enhanced magnetic resonance imaging (MRI) with gadobenate dimeglumine-enhanced MRI for preoperatively detecting hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Eighteen consecutive patients (17 men and one woman, age range: 31-73 years) with 22 HCCs underwent examinations with gadoxetic acid enhanced MRI and gadobenate dimeglumine-enhanced MRI on a 3.0-Tesla unit. The diagnosis of HCC was established after surgical resection and pathological conformation. Three observers independently reviewed each MR image in a random order on a tumor-by-tumor basis. The diagnostic accuracy of these techniques for the detection of HCC was assessed by performing an alternative free-response receiver operating characteristic (ROC) analysis. The sensitivity and positive predictive values were evaluated. RESULTS: The average value of the area under the ROC curve (Az) for gadoxetic acid enhanced MRI (0.887) was not significantly different from the Az (0.899) for gadobenate dimeglumine-enhanced MRI (p > 0.05). The overall sensitivities of gadoxetic acid enhanced MRI and gadobenate dimeglumine-enhanced MRI were 80% and 83%, respectively, with no significant difference (p > 0.05). The differences of the positive predictive values for the two contrast agents for each observer were not statistically significant (p > 0.05). CONCLUSION: The diagnostic performance of gadoxetic acid-enhanced MRI and gadobenate dimeglumine-enhanced MRI for preoperatively detecting HCC is quite similar.

Inflammatory Hepatic Nodules Associated with Urinary Tract Infection in Two Pediatric Patients

Inflammatory nodule in the liver associated with acute urinary infection is an uncommon presentation. We recently experienced two pediatric patients, admitted for urinary tract infection, in whom a solitary hyperechoic nodule or multiple low echoic nodules in the liver were incidentally discovered. All patients complained of fever, and urine culture results were positive for Klebsiella, Streptococcus, and Escherichia coli. After receiving treatment with antibiotics, the hepatic nodules gradually decreased in size and completely disappeared.

Comparison of Ferucarbotran-Enhanced MRI and Triple-Phase MDCT for the Detection of Hepatocellular Carcinoma in Advanced Liver Cirrhosis

PURPOSE: To compare the diagnostic performance of ferucarbotran-enhanced MRI at 1.5-T with triple-phase multidetector-row helical CT (MDCT) to detect hepatocellular carcinoma in patients with advanced liver cirrhosis. MATERIALS AND METHODS: Twenty patients with advanced liver cirrhosis (Child's class B:C = 8:12) underwent ferucarbotran-enhanced MRI and triple-phase MDCT prior to liver transplantation. The mean time interval between the two imaging techniques was 18 days (range, 1-35 days). Three radiologists independently reviewed both images on a lesion-by-lesion basis and interpreted them for comparison with the pathologic findings of the explanted livers. As well, the sensitivity and an alternative-free response receiver operating characteristics (ROC) analysis was used to evaluate the diagnostic performance of each technique. RESULTS: The mean area under the ROC curve (Az) was significantly higher for the triple-phase MDCT (0.766) compared to the ferucarbotran-enhanced MRI (0.675) (p < 0.001). Similarly, the mean sensitivity of the triple-phase MDCT (60.3%) exceeded the ferucarbotran-enhanced MRI (43.1%). The results indicate that the triple-phase MDCT provides significantly greater mean sensitivity than the ferucarbotran-enhanced MRI (p < 0.001). CONCLUSION: The triple-phase MDCT provided a better diagnostic performance and higher sensitivity than the ferucarbotran-enhanced MRI for the detection of hepatocellular carcinomas in patients with advanced liver cirrhosis.

Evaluation of Fibrosis in Liver Cirrhosis by Superparamagnetic Iron Oxide (SPIO)-Enhanced MR Imaging: Does the Radiological Non-Invasive Fibrosis Index Correlate with the Laboratory Non-Invasive Fibrosis Index?

PURPOSE: To evaluate the correlation between the radiological non-invasive hepatic fibrosis index (RNHFI), as determined by SPIO-enhanced MRI, and the laboratory non-invasive hepatic fibrosis index. MATERIALS AND METHODS: Patients (99 total: 61 men and 38 women; mean age: 58 years) who underwent SPIO-enhanced MRI (1.5T) during 5 years included. These patients were subdivided into a liver cirrhosis group (LCG) and a non-liver cirrhosis group (non-LCG). Using PACS view, we measured the RNHFI (mean standard deviation of hepatic signal intensity (SD), noise-corrected coefficient of variation (CV)) of three ROIs in the liver parenchyma by SPIO-enhanced MRI. The laboratory non-invasive hepatic fibrosis index (AST-platelet ratio index (APRI)) of all patients was calculated from the laboratory data. We compared the RNHFI and APRI of LCG with those of non-LC group using Student's t-test. A bivariate correlation was performed to investigate the relationship between the RNHFI and APRI in the LCG. RESULTS: For the LCG, mean values of SD and CV by SPIO-enhanced MRI were 10.3 +/-3.7 and 0.19+/-0.08, respectively. For the non-LCG, mean values of SD and CV were 6.5+/-1.6 and 0.08+/-0.05, respectively. The mean APRI of the LCG and the non-LCG were 2.04+/-1.7 and 0.32+/-0.32, respectively. The RNHFI and APRI were significantly different between both groups (p<05). For the LCG, the bivariate correlation between SD and APRI revealed a statistically significant positive correlation (r=0.5, p<0.001). In both groups, there was no statistically significant correlation between CV and APRI. CONCLUSION: A measurement of SD can be a simple and useful method for the evaluation of hepatic fibrosis.

Early Hepatocellular Carcinoma: Three-Phase Helical CT Features of 16 Patients

OBJECTIVE: To evaluate the three-phase helical CT features of early hepatocellular carcinomas, based on the new Japanese classification. MATERIALS AND METHODS: Over the course of an eight-year period, we collected 16 pathologically proven early hepatocellular carcinomas from 16 patients having undergone a three-phase helical CT prior to surgery. The three-phase CT images were acquired at 20-35 sec (arterial phase), 70 sec (portal phase), and 180 sec (equilibrium phase) from the begining of intravenous injection of contrast material. All the CT images were retrospectively analyzed by two radiologists in consensus, based on their description of morphologic (size, margin, fibrous capsule and mosaic pattern) and enhancement patterns of tumors. RESULTS: Only seven (44%) of the 16 early hepatocellular carcinomas having undergone a CT were described (mean diameter, 1.2 cm; range, 0.4-2.5 cm). All the tumors had an ill-defined margin with no fibrous capsule. The mosaic pattern was found in only one tumor. Only three (43%) of the seven tumors detected on CT were hyperattenuating during the arterial phase. The four remaining tumors (25%) were hypoattenuating throughout the three phases. CONCLUSION: Despite the higher resolution provided by the three phase scans, the contrast-enhanced CT provides only limited detection of the variable morphologic and enhancement features of early hepatocellular carcinomas.