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.

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.

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.

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.

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.

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.

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.

Depiction of Viable Tumor in Hepatocellular Carcinoma Treated with Transarterial Chemoembolization: Multiphasic Helical CT with Review of the Previous Serial CT Images

OBJECTIVE: The purpose of our study was to assess whether a review of multiphasic helical CT combined with the previous serial CT images could be helpful to depict a viable tumor in hepatocellular carcinoma treated with transarterial chemoembolization. MATERIALS AND METHODS: Twenty-four consecutive patients with 35 hepatocellular carcinomas underwent transarterial chemoembolization followed by hepatic resection. First, three radiologists independently analyzed the last CT images taken before resection for the presence of viable tumor. A second analysis was then performed using the last CT combined with the previous serial CT images. The CT analyses were then compared with the pathologic results. The added value of the review of the previous serial CT images was evaluated by performing a receiver operating characteristic analysis. The sensitivity, specificity and diagnostic accuracy for the depiction of viable tumor were also assessed, and the characteristics of the false-negative lesions were pathologically evaluated. RESULTS: The mean diagnostic accuracies (Az values) for the depiction of viable tumor with using the last CT alone and with the review of the previous serial CT images for all observers were 0.885 and 0.901, respectively, which were not significantly difference (p> 0.05). However, the additional review of the previous serial CT images allowed the observers to render a correct diagnosis for three lesions that had been incorrectly diagnosed with the review of last CT alone. The sensitivity, specificity and diagnostic accuracy of the last CT along with the review of the previous serial CT images were 78%, 97% and 84%, respectively. All of the 16 false-negative lesions diagnosed by each observer showed 90% or greater necrosis on the pathologic examination. CONCLUSION: For the depiction of viable tumor in hepatocellular carcinoma treated with transarterial chemoembolization, although the difference in the diagnostic accuracies was not statistically significant, a review of the multiphasic helical CT combined with the previous serial CT images could help reach a correct diagnosis for those lesions incorrectly diagnosed with the review of the last CT alone.

Analysis of the Hepatic Segments on the Isotropic Multi-planar Reformatted CT Images

PURPOSE: We wanted to evaluate the diverse distribution and relation of the hepatic segments, as divided by the portal venous territories, on the isotropic multi-planar reformatted (MPR) CT images and we wanted to find their correlation to the intrahepatic venous structures. MATERIALS AND METHODS: Fifty adult patients who underwent portal phase CT images and who had the normal liver contours at CT were included in our study. The portal phase images were obtained with a slice collimation and reconstruction interval of 1.25 mm, and they were reformatted in the coronal and sagittal planes with a slab thickness of 3 mm. For analysis of these MPR images, various terms were newly defined according to the portal venous territories (e.g., three vertical planes [right, middle and left] and one transverse plane and their plane angles, the transverse and longitudinal angles). Also, the dominant segments of the right lobe were newly divided into the S7- and S8-dominant types by comparing the transverse angles. The imaging analysis was then conducted for the following: (1) the diversity of the three vertical planes and the one transverse plane and their plane angles, (2) the proportion of the dominant segments of the right lobe and their relation with the plane angles, and (3) the correlation between the dominant segments and the intrahepatic venous structures. RESULTS: The number of the S7- and the S8-dominant types was 21 and 29, respectively. The vertical and transverse planes were undulating and diverse according to the dominant segments as follows: the plane angles of the right vertical and middle vertical planes were more vertical in the S7-dominant type than in the S8-dominant type (p < 0.001). The right transverse plane angle was more horizontal in the S8-dominant type (p < 0.05). The left transverse plane angle seemed to be rather vertical than horizontal. For the intrahepatic venous structures, despite of our limited data, the anomalous intrahepatic venous structures might have some correlation with the dominant segments. CONCLUSION: According to our results, we suggest that the isotropic MPR images could successfully depict the vertical and transverse planes of the real hepatic segments, as divided by the portal venous territories, which were diverse according to their dominant types.

Comparison of Transvaginal Ultrasonography with Hysterosonography as a Screening Method in Patients with Abnormal Uterine Bleeding

OBJECTIVE: To assess the utility of hysterosonography (HS) as a screening method in patients with abnormal uterine bleeding. MATERIALS AND METHODS: We retrospectively reviewed transvaginal ultrasonography (TVS) and HS for 105 patients whose diagnosis was confirmed pathologically. All 105 patients were initially evaluated on the same day with both TVS and HS. On TVS and HS examination, endometrial cavitary lesions were classified as diffuse hyperplasia, endometrial polyp, endometrial cancer, uterine synechia and submucosal leiomyoma. Hysteroscopy with biopsy (n=35), curettage (n=60) or hysterectomy (n=10) was performed, and the results of TVS and HS examination were correlated with the pathological findings. RESULTS: The sensitivity and specificity were 79.0% and 45.8% for TVS, and 95.1% and 83.3% for HS, respectively. The positive and negative predictive values were 83.0% and 39.3% for TVS, and 95.1% and 83.3% for HS, respectively. Twenty-seven showed a discrepancy between the TVS and HS, and eight cases showed a discrepancy between HS and the pathologic diagnosis. CONCLUSION: TVS is a sensitive method to evaluate the endometrial cavitary lesions, but it often does not provide the physician with sufficient diagnostic information. With its higher sensitivities, specificities and positive and negative predictive values, HS can be better used than TVS in evaluating those patients with abnormal uterine bleeding.

Overlapping Ablation Using a Coaxial Radiofrequency Electrode and Multiple Cannulae System: Experimental Study in ex-Vivo Bovine Liver

OBJECTIVE: To assess the sizes and configurations of thermal zones after overlapping ablations using a coaxial radiofrequency (RF) electrode and multiple cannulae in ex-vivo bovine liver. MATERIALS AND METHODS: For ablation procedures, a coaxial RF electrode and introducer set was used. Employing real-time ultrasound guidance and overlapping techniques in explanted, fresh bovine liver, we created five kinds of thermal zones with one (n=10), two (n=8), four (n=3), and six ablation spheres (n=3). Following ablation, MR images were obtained and the dimensions of all thermal zones were measured on the longitudinal or transverse section of specimens. The shape of the composite ablation zones was evaluated using three-dimensional MR image reconstruction. RESULTS: At gross pathologic examination of ten single-ablation zones (spheres), the long-axis (transverse) and short-axis lengths of zones ranged from 3.7 to 4.4 (mean, 4.1) cm and from 3.5 to 4.0 (mean, 3.7) cm, respectively. The long-axis (transverse) and short-axis lengths of double-ablation zones (cylinders) with 23% overlap ranged from 7.0 to 7.7 (mean, 7.3) cm and from 3.0 to 3.9 (mean, 3.5) cm, respectively; those with 58% overlap ranged from 6.0 to 6.4 (mean, 6.2) cm and from 3.8 to 4.6 (mean, 4.3) cm, respectively. The long-axis (diagonal) and short-axis lengths on a transverse section of four-ablation zones (cakes) ranged from 8.5 to 9.7 (mean, 9.1) cm and from 3.0 to 4.1 (mean, 3.7) cm, respectively. Gross pathologic examination of three composite six-ablation zones (spheres) showed that the long-axis (diagonal) and short-axis lengths of zones ranged from 9.0 to 9.9 (mean, 9.4) cm and from 6.8 to 7.5 (mean, 7.2) cm, respectively. T2-weighted MR images depicted low-signal thermal zones containing multiple curvilinear and spotty regions of hyperintensity. CONCLUSION: Using a coaxial RF electrode and multiple cannulae, together with ultrasound guidance and precise overlapping ablation techniques, we successfully created predictable thermal zones in ex-vivo bovine liver.

Epithelioid Hemangioendothelioma of the Liver: Helical CT Findings

PURPOSE: To describe the morphologic features and enhancement patterns of the helical computed tomography (CT) observed in patients with epithelioid hemangioendothelioma (EH) of the liver. MATERIALS AND METHODS: Seven patients (four men and three women; mean age, 41 years) with pathologically proven EHs underwent monophasic (n=2), biphasic (n=2) or triphasic (n=3) helical CT, and the findings were retrospectively analysed. The morphologic features to which attention was directed were tumor number, size, location, shape, margin, surface, the presence of adjacent capsular retraction, vascular encasement and confluent mass formation, while the enhancement pattern was examined in terms of the appearance and degree of enhancement during the arterial or portal phase, and enhancement change during the portal and equilibrium phases. RESULTS: Six patients had multiple tumors, and one had a single lesion. The maximon diameter of these tumors ranged from 0.5 to 12.0 (mean, 3.2) cm, and almost all occurred in the peripheral portion of the liver. The shape, margin and surface features of the tumors varied: in four patients, the margin was poorly defined and the surface was smooth, while in five, adjacent capsular retraction was observed. Vascular encasement was noted in five of six patients with hepatic vessels abutting the tumors, and in all three who were follow up, the growth pattern involved confluent mass formation. In all patients, many tumors showed either nodular (n=3) or irregular (n=4) peripheral enhancement. In all five patients who underwent multiphasic CT, centripetal enhancement was demoustrated. CONCLUSION: Our results disclosed that most patients with EH had multiple tumors, and that almost all were located in the peripheral portion of the liver and involved capsular retraction. The other common CT findings were vascular encasement and a centripetal enhancement pattern. When these CT findings are observed in patients with hepatic tumors, EH should be included in the differential diagnosis.

Unenhanced Spiral CT in Acute Ureteral Colic: A Replacement for Excretory Urography?

OBJECTIVE: To compare the usefulness of unenhanced spiral CT (UCT) with that of excretory urography (EU) in patients with acute flank pain. MATERIALS AND METHODS: Thirty patients presenting with acute flank pain under-went both UCT and EU. Both techniques were used to determine the presence, size, and location of urinary stone, and the presence or absence of secondary signs was also evaluated. The existence of ureteral stone was confirmed by its removal or spontaneous passage during follow-up. The absence of a stone was determined on the basis of the clinical and radiological evidence. RESULTS: Twenty-one of the 30 patients had one or more ureteral stones and nine had no stone. CT depicted 22 of 23 calculi in the 21 patients with a stone, and no calculus in all nine without a stone. The sensitivity and specificity of UCT were 96% and 100%, respectively. EU disclosed 14 calculi in the 21 patients with a stone and no calculus in eight of the nine without a stone. UCT and EU demon-strated secondary signs of ureterolithiasis in 15 and 17 patients, respectively. CONCLUSION: For the evaluation of patients with acute flank pain, UCT is an excellent modality with high sensitivity and specificity. In near future it may replace EU.