The potential of an artificial intelligence for diagnosing MRI images in rectal cancer: multicenter collaborative trial.

BACKGROUND: An artificial intelligence-based algorithm we developed, mrAI, satisfactorily segmented the rectal tumor, rectum, and mesorectum from MRI data of rectal cancer patients in an initial study. Herein, we aimed to validate mrAI using an independent dataset. METHODS: We utilized MRI images collected in another nationwide research project, "Open versus Laparoscopic Surgery for Advanced Low Rectal Cancer Patients". MRIs from 467 cases with upfront surgery were utilized; six radiologists centralized the MRI evaluations. The diagnostic accuracies of mrAI and the radiologists for tumor depth were compared using pathologic diagnosis as a reference. RESULTS: For all cases, centralized diagnosis demonstrated 84.2% sensitivity, 37.7% specificity, and 73.7% accuracy; mrAI exhibited 70.6% sensitivity, 61.3% specificity, and 68.5% accuracy. After limiting MRIs to those acquired by a Philips scanner, with an inter-slice spacing of ≤ 6 mm-both conditions similar to those used in the development of mrAI-the performance of mrAI improved to 76.8% sensitivity, 76.7% specificity, and 76.7% accuracy, while the centralized diagnosis showed 81.8% sensitivity, 36.7% specificity, and 71.3% accuracy. Regarding relapse-free survival, the prognosis for tumors staged ≥ T3 was significantly worse than for tumors staged ≤ T2 (P = 0.0484) in the pathologic diagnosis. While no significant difference was observed between ≥ T3 and ≤ T2 tumors in the centralized diagnosis (P = 0.1510), the prognosis for ≥ T3 was significantly worse in the mrAI diagnosis (P = 0.0318). CONCLUSION: Proper imaging conditions for MRI can enhance the accuracy of mrAI, which has the potential to provide feedback to radiologists without overestimating tumor stage.

Impact of renal sinus protrusions on achieving trifecta in robot-assisted partial nephrectomy.

Objective: The objective of this work is to assess the relationship between the morphological characteristics of a central tumour and the perioperative outcomes of robot-assisted partial nephrectomy (RAPN). Subjects and Methods: We retrospectively analysed the data from 186 patients with central tumours involving the renal sinus, who underwent RAPN in a single-centre study between February 2015 and June 2022. All cases were assigned a RENAL nephrometry score based on preoperative images. The shape of the protruding portion of the tumour was classified into four types: 'flat', 'spherical', 'single-hump', and 'complex-hump', and was independently assessed by two readers. The trifecta is defined as the warm ischemia time within 25 min, negative surgical margins, and no major postoperative complications. Univariate and multivariate analyses were performed to identify the factors associated with the failing trifecta. Results: Trifecta was achieved in 113 cases (60.8%), and the achievement rate in flat, spherical, single-hump, and complex-hump types was 83.3%, 74.5%, 64.3%, and 21.3%, respectively. Prolonged warm ischemia time was the primary cause of the failure to achieve the trifecta. The rate of positive surgical margins and upstage to pathological T3a was greater for complex humps while the rate of major complications and postoperative GFR preservation did not differ between shapes. On multivariate analysis for failing trifecta achievement, the complex-hump protrusion was found to be an independent positive predictor (odds ratio: 15.8; p < 0.001), whereas the height and width of protrusion were not significantly related. Conclusions: The degree of difficulty varied among central tumours, and it was not possible to precisely measure it with existing scoring systems. Complex-hump protrusions strongly correlate with failure to achieve the trifecta. Preoperative assessment of the morphology of protrusion is useful for predicting outcomes.

Prognostic analysis of curatively resected pancreatic cancer using harmonized positron emission tomography radiomic features.

BACKGROUND: Texture features reflecting tumour heterogeneity enable us to investigate prognostic factors. The R package ComBat can harmonize the quantitative texture features among several positron emission tomography (PET) scanners. We aimed to identify prognostic factors among harmonized PET radiomic features and clinical information from pancreatic cancer patients who underwent curative surgery. METHODS: Fifty-eight patients underwent preoperative enhanced dynamic computed tomography (CT) scanning and fluorodeoxyglucose PET/CT using four PET scanners. Using LIFEx software, we measured PET radiomic parameters including texture features with higher order and harmonized these PET parameters. For progression-free survival (PFS) and overall survival (OS), we evaluated clinical information, including age, TNM stage, and neural invasion, and the harmonized PET radiomic features based on univariate Cox proportional hazard regression. Next, we analysed the prognostic indices by multivariate Cox proportional hazard regression (1) by using either significant (p < 0.05) or borderline significant (p = 0.05-0.10) indices in the univariate analysis (first multivariate analysis) or (2) by using the selected features with random forest algorithms (second multivariate analysis). Finally, we checked these multivariate results by log-rank test. RESULTS: Regarding the first multivariate analysis for PFS after univariate analysis, age was the significant prognostic factor (p = 0.020), and MTV and GLCM contrast were borderline significant (p = 0.051 and 0.075, respectively). Regarding the first multivariate analysis of OS, neural invasion, Shape sphericity and GLZLM LZLGE were significant (p = 0.019, 0.042 and 0.0076). In the second multivariate analysis, only MTV was significant (p = 0.046) for PFS, whereas GLZLM LZLGE was significant (p = 0.047), and Shape sphericity was borderline significant (p = 0.088) for OS. In the log-rank test, age, MTV and GLCM contrast were borderline significant for PFS (p = 0.08, 0.06 and 0.07, respectively), whereas neural invasion and Shape sphericity were significant (p = 0.03 and 0.04, respectively), and GLZLM LZLGE was borderline significant for OS (p = 0.08). CONCLUSIONS: Other than the clinical factors, MTV and GLCM contrast for PFS and Shape sphericity and GLZLM LZLGE for OS may be prognostic PET parameters. A prospective multicentre study with a larger sample size may be warranted.

Prognostic Impact of Lateral Pelvic Node Dissection on the Survival of Patients in Low Rectal Cancer Subgroups Based on Lymph Node Size.

BACKGROUND: Lateral pelvic node (LPN) dissection (LPND) is considered a promising technique for treating low rectal cancer; however, there is insufficient evidence of its prognostic value. Using centrally reviewed preoperative pelvic magnetic resonance (MR) images, this study aimed to find the patient population who has benefited from LPND. PATIENTS AND METHODS: MR images of patients from 69 institutes with stage II-III low rectal cancer were reviewed by experienced radiologists. Recurrence-free survival (RFS), overall survival (OS), and short-term outcomes were measured. RESULTS: In total, 731 preoperative MR images were reviewed (excluding patients with short-axis LPN ≥ 10 mm). Of these, 322 underwent total mesorectum excision (TME) without LPND (non-LPND group), and 409 underwent TME with LPND (LPND group). Preoperative treatment was performed for 40% and 25% of patients in the non-LPND and LPND groups, respectively. The incidence of postoperative complications was higher in the LPND group (44.5%) than in the non-LPND group (33.2%; P = 0.002). Among patients with LPNs < 5 mm, OS and RFS curves were not significantly different between the groups. Among patients with LPNs ≥ 5 mm, the LPND group had significantly higher 5-year OS and RFS than the non-LPND group (OS: 81.9% versus 67.3%; RFS: 69.4% versus 51.6%). On multivariate analysis of LPN ≥ 5 mm cases, LPND was independently associated with RFS. CONCLUSIONS: Despite the high incidence of postoperative complications, this study showed the prognostic impact of LPND on low rectal cancer patients with LPNs (≥ 5 mm, < 10 mm short axis) measured by experienced radiologists. Trial registration UMIN-ID: UMIN000013919.

Imaging findings of granulocyte colony-stimulating factor-producing tumors: a case series and review of the literature.

Granulocyte colony-stimulating factor (G-CSF)-producing tumors have an aggressive clinical course. Here, we report five cases of G-CSF-producing tumors and review the literature, focusing on imaging findings related to tumor-produced G-CSF. In addition to our cases, we identified 30 previous reports of G-CSF-producing tumors on which 18F-fluorodeoxyglucose positron emission tomography (FDG-PET)/CT, bone scintigraphy, or evaluation of bone marrow MR findings was performed. White blood cell count, serum C-reactive protein, and serum interleukin-6 were elevated in all cases for which these parameters were measured. G-CSF-producing tumors presented large necrotic masses (mean diameter 83.2 mm, range 17-195 mm) with marked FDG uptake (mean maximum standardized uptake value: 20.09). Diffuse FDG uptake into the bone marrow was shown in 28 of the 31 cases in which FDG-PET/CT was performed. The signal intensity of bone marrow suggested marrow reconversion in all seven MRI-assessable cases. Bone scintigraphy demonstrated no significant uptake, except in two cases with bone metastases. Splenic FDG uptake was increased in 8 of 10 cases in which it was evaluated. These imaging findings may reflect the effects of tumor-produced G-CSF. The presence of G-CSF-producing tumors should be considered in patients with cancer who show these imaging findings and marked inflammatory features of unknown origin.

Imaging of Pancreaticobiliary Maljunction.

Pancreaticobiliary maljunction (PBM) is a congenital malformation in which the pancreatic and bile ducts join outside the duodenal wall, usually forming a long common channel. A major issue in patients with PBM is the risk of biliary cancer. Because the sphincter of Oddi does not regulate the pancreaticobiliary junction in PBM, pancreatic juice frequently refluxes into the biliary tract and can cause various complications, including biliary cancer. Most cancers arise in the gallbladder or dilated common bile duct, suggesting that bile stasis is related to carcinogenesis. Early diagnosis and prophylactic surgery to reduce the risk of cancer are beneficial. The diagnosis of PBM is made mainly on the basis of imaging findings. The development of diagnostic imaging modalities such as multidetector CT and MR cholangiopancreatography has provided radiologists with an important role in diagnosis of PBM and its complications. Radiologists should be aware of PBM despite the fact that it is rare in non-Asian populations. In this review, the authors present an overview of PBM with emphasis on diagnosis and management of PBM and its complications. For early diagnosis, the presence of extrahepatic bile duct dilatation or gallbladder wall thickening may provide a clue to PBM with or without biliary dilatation, respectively. The pancreaticobiliary anatomy should be closely examined if imaging reveals these findings. Radiologists should also carefully evaluate follow-up images in PBM patients even years after prophylactic surgery because residual bile ducts remain at risk for cancer.©RSNA, 2020.

Optimizing b-values for accurate depiction of pancreatic cancer with tumor-associated pancreatitis on computed diffusion-weighted imaging.

PURPOSE: To determine the optimal b-value for accurate depiction of pancreatic cancer (PC) in patients with active tumor-associated pancreatitis (TAP), using computed diffusion-weighted imaging (cDWI) with a range of b-values up to 3000 s/mm2. METHODS: The study protocol was approved by the institutional review board. We retrospectively analyzed 34 consecutive PC cases with active TAP who underwent pancreatectomy without preoperative therapy. Four cDWI datasets with b-values of 1500-3000 s/mm2 (cDWI1500-cDWI3000) were generated from the original DWI datasets with b-values of 0 and 1000 s/mm2 obtained using a 3-T scanner. Two board-certified radiologists evaluated images qualitatively (tumor conspicuity and total image quality), and another two board-certified radiologists placed regions of interest for quantitative evaluations (apparent diffusion coefficient [ADC] values of both lesions, contrast ratio [CR] of PC to active TAP, and volume ratio [VR] of PC to surgical specimen). RESULTS: As the b-value increased, tumor conspicuity improved significantly in cDWI2000 and cDWI2500 (P = 0.0121 and 0.0015, respectively), although total image quality decreased in all cDWIs compared with DWI1000 (P < 0.0001). Significantly lower ADC values were seen in PC (P < 0.0001). All cDWI groups showed positive correlation between the tumor conspicuity and ADC difference between PC and TAP. CR increased with the b-value, while VR decreased. Significant equivalence of VR to the surgical specimen was seen on cDWI2000 (P = 0.0031). CONCLUSION: Accurate depiction of PC was optimal with cDWI2000 in the presence of active TAP.

Imaging Characteristics of Liver Metastases Overlooked at Contrast-Enhanced CT.

OBJECTIVE: The purpose of this study was to evaluate the imaging characteristics of liver metastases overlooked at contrast-enhanced CT. MATERIALS AND METHODS: The records of 746 patients with a diagnosis of liver metastases from colorectal, breast, gastric, or lung cancer between November 2010 and September 2017 were reviewed. Images were reviewed when liver metastases were first diagnosed, and images from prior contrast-enhanced CT examinations were checked if available. These lesions were classified into two groups: missed lesions (those missed on the prior images) and detected lesions (those correctly identified and invisible on the prior images or there were no prior images). Tumor size, contrast-to-noise ratio, location, presence of coexisting liver cysts and hepatic steatosis, and indications for examination were compared between the groups. The t test and Fisher exact test were used to analyze the imaging characteristics of previously overlooked lesions. RESULTS: The final analysis included 137 lesions, of which 68 were classified as missed. In univariate analysis, contrast-to-noise ratio was significantly lower in missed lesions (95% CI, 2.65 ± 0.24 vs 3.90 ± 0.23; p < 0.001). The proportion of subcapsular lesions (odds ratio, 3.44; p < 0.001), hepatic steatosis (odds ratio, 6.35; p = 0.007), and examination indication other than survey of malignant tumors (odds ratio, 9.07; p = 0.02) were significantly higher for missed lesions. CONCLUSION: Liver metastases without sufficient contrast enhancement, those in patients with hepatic steatosis, those in subcapsular locations, and those found at examinations for indications other than to assess for tumors were significantly more likely to be overlooked.

Duodenal obstruction induced by retroperitoneal progression of bladder cancer: a report of two cases.

Bladder cancer usually forms a papillary structure. Progression along the cavity or membranous structures surrounding the bladder, rectum, or retroperitoneum without formation of a discrete mass is rare. We here present two patients with duodenal obstruction caused by retroperitoneal progression of bladder cancer, in both of whom computed tomography revealed bladder and rectal wall thickening with a malignant target sign, thickened mesorectal fascia with abnormal tissue stranding, and increased perirectal fat density. Both cancers progressed despite treatment, as indicated by faint abnormal tissue stranding and increased retroperitoneal fat density along the retromesenteric plane from the pelvis to the duodenum. Subsequently, both patients developed obstruction in the horizontal portion of the duodenum, still without formation of a mass lesion. These two patients highlight the challenges associated with retroperitoneal invasion by bladder cancer in the absence of a mass lesion and underscore the importance of considering cancer progression in patients with bowel obstruction, even when there is no obvious mass lesion and/or only minor retroperitoneal findings. Progression along the retromesenteric plane may be the key pathway via which progressive bladder cancer results in duodenal obstruction without or with a minor mass lesion.

Imaging findings of hemorrhagic hepatic cysts with enhancing mural nodules.

PURPOSE: This study aimed to evaluate the clinical and radiological findings of hemorrhagic hepatic cysts with enhancing mural nodules. METHODS: The radiology databases of five facilities were retrospectively searched for reports indicating hemorrhagic hepatic cysts or hepatic cystic tumors. Cases of hemorrhagic hepatic cysts with enhancing mural nodules based on pathological or radiological findings were identified and reviewed. RESULTS: We included 14 cases (11 female and 3 male) with a mean patient age of 72.6 years. Up until the enhancing mural nodules were detected, the cysts had decreased in size in all ten cases for which radiological imaging was available for a period of > 3 years previous to detection. Dynamic contrast-enhanced CT or MRI showed focal enhancement in the early phase and progressive centrifugal enhancement in the delayed phase in all 16 mural nodules ≥ 10 mm in diameter. Thirteen of 14 MRI assessable enhancing mural nodules ≥ 10 mm in diameter showed a hypointense rim with central hyperintensity on T2-weighted imaging. All cases showed calcification of the cyst wall. In the three referred cases, 18F-fluorodeoxyglucose (FDG) positron emission tomography/CT demonstrated no intense FDG uptake in the enhancing mural nodules. In the four resected cases, histopathology of the enhancing mural nodules revealed neovascularization within an organized hematoma, including extensive dilated vessels and hemangioma-like lesions. CONCLUSIONS: Features including a decrease in cyst size, a progressive centrifugal enhancing pattern on dynamic contrast-enhanced CT or MRI, a hypointense rim with central hyperintensity on T2-weighted MRI, and cyst wall calcification may indicate a hemorrhagic hepatic cyst.

Selective visualization of pelvic splanchnic nerve and pelvic plexus using readout-segmented echo-planar diffusion-weighted magnetic resonance neurography: A preliminary study in healthy male volunteers.

PURPOSE: To evaluate the potential of readout-segmented echo-planar diffusion-weighted magnetic resonance neurography (RS-EPI DW-MRN) for the selective visualization of pelvic splanchnic nerve and pelvic plexus in healthy male volunteers. MATERIALS AND METHODS: Institutional review board approval and written informed consent were obtained. RS-EPI DW-MRN images were acquired from thirteen healthy male volunteers aged 25-48 years between September 2013 and December 2013. For RS-EPI DW-MRN, the following parameters were used: spatial resolution, 1.1×1.1×2.5mm; b-value, 250s/mm2; number of readout-segments, seven; and acquisition time, 7min 45s. For qualitative assessment, two abdominal radiologists independently evaluated the visibility of the pelvic splanchnic nerves and pelvic plexuses bilaterally in each subject on oblique coronal thin-slab 10-mm-thick maximum intensity projection images and scored it with a 4-point grading scale (excellent, good, fair, poor). Both readers scored twice at 6-month intervals. Inter-observer and intra-observer variability were evaluated using Cohen's quadratically weighted κ statistics. Image artifact level was scored on a 4-point grading scale by other two abdominal radiologists in order to evaluate the correlation between the nerve visibility and the severity of imaging artifacts using the Spearman's correlation coefficient. RESULTS: Qualitative grading showed the following success rate (number of nerves qualitatively scored as excellent or good divided by total number of nerves): reader 1 (first set), 73% (19/26); reader 2 (first set), 77% (20/26); reader 1 (second set), 81% (21/26); and reader 2 (second set), 77% (20/26). Inter-observer agreement between readers 1 and 2 was excellent: κ=0.947 (first set) and 0.845 (second set). Intra-observer agreement was also excellent: κ=0.810 (reader 1) and 0.946 (reader 2). The visibility of pelvic splanchnic nerve and pelvic plexus showed a moderate correlation with the image artifact level (ρ=0.54, p=0.004). CONCLUSION: This study demonstrated that RS-EPI DW-MRN is a promising approach for selectively visualizing the pelvic splanchnic nerve and pelvic plexus.

Usefulness of breath-hold inversion recovery-prepared T1-weighted two-dimensional gradient echo sequence for detection of hepatocellular carcinoma in Gd-EOB-DTPA-enhanced MR imaging.

The aim is to evaluate the diagnostic performance and the added value of breath-hold inversion recovery-prepared T1-weighted two-dimensional gradient echo (IR-2D-GRE) sequence for detection of hepatocellular carcinoma (HCC) in patients with insufficient liver parenchymal enhancement during the hepatobiliary phase (HBP) of Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI). Seventeen patients with a quantitative liver-to-spleen contrast ratio of ≤1.5 on HBP images and 36 HCCs were included. Liver-to-lesion contrast ratios on HBP images obtained with IR-2D-GRE sequence were significantly higher than those with three-dimensional gradient echo sequence. The addition of IR-2D-GRE sequence during HBP of Gd-EOB-DTPA-enhanced MRI yielded higher diagnostic accuracy and improved sensitivity.

Additional benefit of computed diffusion-weighted imaging for detection of hepatic metastases at 1.5T.

The aim is to investigate the added value of computed diffusion-weighted magnetic resonance imaging (DWI) at 1.5T in detecting hepatic metastases. Fifty-six patients with a total of 100 hepatic metastases were included. Computed DWI was synthesized from lower b values. Diagnostic performance was evaluated by receiver operating characteristic (ROC) curve analysis. The sensitivity was calculated and analyzed. The area under the ROC curve of the computed DWI was larger than that of acquired DWI. Both readers detected significantly more hepatic metastases with combined acquired DWI/computed DWI. Combined use of computed DWI with acquired DWI helped to provide higher sensitivity at 1.5T.

Diffusion-weighted intravoxel incoherent motion imaging of renal tumors with histopathologic correlation.

PURPOSE: The aim of this study was to use intravoxel incoherent motion diffusion-weighted imaging to discriminate subtypes of renal neoplasms and to assess agreement between intravoxel incoherent motion (perfusion fraction, fp) and dynamic contrast-enhanced magnetic resonance imaging (MRI) metrics of tumor vascularity. SUBJECTS AND METHODS: In this Health Insurance Portability and Accountability Act-compliant, institutional review board-approved prospective study, 26 patients were imaged at 1.5-T MRI using dynamic contrast-enhanced MRI with high temporal resolution and diffusion-weighted imaging using 8 b values (range, 0-800 s/mm). Perfusion fraction (fp), tissue diffusivity (Dt), and pseudodiffusivity (Dp) were calculated using biexponential fitting of the diffusion data. Apparent diffusion coefficient (ADC) was calculated with monoexponential fit using 3 b values of 0, 400, and 800 s/mm. Dynamic contrast-enhanced data were processed with a semiquantitative method to generate model-free parameter cumulative initial area under the curve of gadolinium concentration at 60 seconds (CIAUC60). Perfusion fraction, Dt, Dp, ADC, and CIAUC60 were compared between different subtypes of renal lesions. Perfusion fraction was correlated with CIAUC60. RESULTS: We examined 14 clear cell, 4 papillary, 5 chromophobe, and 3 cystic renal cell carcinomas (RCCs). Although fp had higher accuracy (area under the curve, 0.74) for a diagnosis of clear cell RCC compared with Dt or ADC, the combination of fp and Dt had the highest accuracy (area under the curve, 0.78). The combination of fp and Dt diagnosed papillary RCC and cystic RCC with 100% accuracy, and clear cell RCC and chromophobe RCC, with 86.5% accuracy. There was significant strong correlation between fp and CIAUC60 (r = 0.82; P < 0.001). CONCLUSION: Intravoxel incoherent motion parameters fp and Dt can discriminate renal tumor subtypes. Perfusion fraction demonstrates good correlation with CIAUC60 and can assess degree of tumor vascularity without the use of exogenous contrast agent.

Comparative study of cisplatin and epirubicin in transcatheter arterial chemoembolization for hepatocellular carcinoma.

AIM: Transcatheter arterial chemoembolization (TACE) is an established treatment for unresectable hepatocellular carcinoma (HCC). However, it is unclear which chemotherapeutic agent should be selected for TACE. The aim of this study was to compare the efficacy of cisplatin (CDDP) with that of epirubicin (EPI) in TACE for patients with unresectable or relapsed HCC. METHODS: We performed a historical cohort study involving 131 patients treated with a first TACE, defined as either an initial treatment for previously untreated HCC or a first treatment for relapsed HCC after curative resections or ablations. Efficacy was estimated as the response rate (RR) and it was adjusted for the confounding factors that were defined in this study. RESULTS: The RR were 62.5% (20/32) for the first TACE with CDDP and 51.5% (51/99) for that with EPI. In the adjusted analysis for a history of hepatectomy, percutaneous treatment combined with TACE and tumor factors, the odds ratio was 1.72 (95% confidence interval [CI] = 0.70-4.48). However, a test for interaction between the number of tumors and the chemotherapeutic agent was statistically significant (P = 0.016). In multiple HCC, the RR were 66.7% (10/17) for CDDP and 39.6% (30/46) for EPI. The odds ratio was 4.11 (95% CI = 1.14-17.2). CONCLUSION: CDDP may be more effective than EPI in TACE for multiple HCC. A randomized controlled study is needed to clarify the efficacy of CDDP in TACE in patients with multiple HCC.

Comparison of gadolinium-EOB-DTPA-enhanced and diffusion-weighted liver MRI for detection of small hepatic metastases.

OBJECTIVE: To compare the accuracy of gadolinium ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI with that of diffusion-weighted MRI (DWI) in the detection of small hepatic metastases (2 cm or smaller). METHODS: Forty-five patients underwent abdominal MRI at 3 T, including T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), heavily T2WI (HASTE), DWI with a b-value of 500 s/mm(2) and contrast-enhanced MRI with Gd-EOB-DTPA. Two groups were assigned and compared: group A (T1WI, T2WI, HASTE and contrast-enhanced study with Gd-EOB-DTPA), and group B (T1WI, T2WI, HASTE and DWI). Two observers independently interpreted the images obtained in a random order. For all hepatic metastases, the diagnostic performance using each imaging set was evaluated by receiver-operating characteristic (ROC) curve analysis. RESULTS: A total of 51 hepatic metastases were confirmed. The area under the ROC curve (Az) of group A was larger than that of group B, and the difference in the mean Az values between the two image sets was statistically significant, whereas, there were three metastases that lay near thin vessels or among multiple cysts and were better visualised in group B than in group A. CONCLUSION: Gd-EOB-DTPA-enhanced MRI showed higher accuracy in the detection of small metastases than DWI.

Improved detection of hepatic metastases from pancreatic cancer using periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) technique after SPIO administration.

OBJECTIVES: The purpose of this study was to evaluate the detection of hepatic metastases from the pancreatic cancer using different MR imaging methods, including superparamagnetic iron oxide (SPIO)-enhanced fat-saturated T2-weighted imaging with periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) technique. MATERIALS AND METHODS: The institutional review board approved this prospective study. Eighty-two patients (mean age, 55 years) underwent different MR imaging with a 1.5-T scanner. Diagnostic performance with receiver operating characteristics (ROC) curves and sensitivity were evaluated for the following image sets: (A) unenhanced images (T1-weighted in-phase and opposed-phase gradient-echo [GRE] images, and fat-saturated T2-weighted turbo spin-echo [TSE] images) that were included in the subsequent image sets, (B) diffusion-weighted images, (C) SPIO-enhanced fat-saturated T2-weighted TSE images with prospective acquisition correction (PACE), (D) SPIO-enhanced T2*-weighted GRE images, and (E) SPIO-enhanced fat-saturated T2-weighted TSE images acquired with PROPELLER and PACE. RESULTS: The areas under the ROC curves were 0.58 +/- 0.05 (mean +/- standard errors), 0.81 +/- 0.04, 0.70 +/- 0.05, 0.80 +/- 0.04, and 0.90 +/- 0.03, and sensitivity was 0.47, 0.69, 0.56, 0.66, and 0.77 for image sets (A) to (E), respectively, for all lesions. Image set (E) had significantly larger area under the ROC curve for detection of hepatic lesions and higher sensitivity than others. CONCLUSIONS: SPIO-enhanced fat-saturated T2-weighted MR imaging with the PROPELLER technique is more effective for detecting hepatic metastases of pancreatic cancer than diffusion-weighted MR imaging, SPIO-enhanced fat-saturated T2WI without the PROPELLER technique, or SPIO-enhanced T2*-weighted GRE imaging.

FDG PET for giant cavernous hemangioma: important clue to differentiate from a malignant vascular tumor in the liver.

Giant cavernous hemangioma of the liver sometimes has a very inhomogeneous appearance with intratumoral degeneration on computed tomography or magnetic resonance imaging, and may mimic a malignant hepatic tumor, including angiosarcoma. There are many reports about F-18 fluorodeoxyglucose (FDG) uptake of angiosarcoma; however, knowledge regarding positron emission tomography findings with FDG for giant hepatic cavernous hemangioma is still limited. We herein present 2 cases of giant hepatic cavernous hemangioma in which low FDG uptake was considered helpful to differentiate from malignant hepatic tumor.

High spatial resolution 3D MR cholangiography with high sampling efficiency technique (SPACE): comparison of 3T vs. 1.5T.

PURPOSE: The aim of this study was to evaluate image quality of 3D MR cholangiography (MRC) using high sampling efficiency technique (SPACE) at 3T compared with 1.5T. METHODS AND MATERIALS: An IRB approved prospective study was performed with 17 healthy volunteers using both 3 and 1.5T MR scanners. MRC images were obtained with free-breathing navigator-triggered 3D T2-weighted turbo spin-echo sequence with SPACE (TR, >2700ms; TE, 780ms at 3T and 801ms at 1.5T; echo-train length, 121; voxel size, 1.1mmx1.0mmx0.84mm). The common bile duct (CBD) to liver contrast-to-noise ratios (CNRs) were compared between 3 and 1.5T. A five-point scale was used to compare overall image quality and visualization of the third branches of bile duct (B2, B6, and B8). The depiction of cystic duct insertion and the highest order of bile duct visible were also compared. The results were compared using the Wilcoxon signed-ranks test. RESULTS: CNR between the CBD and liver was significantly higher at 3T than 1.5T (p=0.0006). MRC at 3T showed a significantly higher overall image quality (p=0.0215) and clearer visualization of B2 (p=0.0183) and B6 (p=0.0106) than at 1.5T. In all analyses of duct visibility, 3T showed higher scores than 1.5T. CONCLUSION: 3T MRC using SPACE offered better image quality than 1.5T. SPACE technique facilitated high-resolution 3D MRC with excellent image quality at 3T.

Small hepatocellular carcinoma: is radiofrequency ablation combined with transcatheter arterial chemoembolization more effective than radiofrequency ablation alone for treatment?

PURPOSE: To prospectively compare combined radiofrequency ablation and transcatheter arterial chemoembolization (TACE) with radiofrequency ablation alone for the treatment of small (< or =3 cm) hepatocellular carcinomas (HCCs). MATERIALS AND METHODS: The ethics committee of the study institution approved the study protocol. Written informed consent was obtained from all patients at enrollment. Eighty-nine patients with 93 HCC nodules 0.8-3.0 cm (mean +/- standard deviation, 1.7 cm +/- 0.5) in diameter were randomly treated with combined radiofrequency ablation and TACE (46 patients with 49 nodules) or with radiofrequency ablation alone (43 patients with 44 nodules). The patients were followed up for 9-68 months (mean +/- standard deviation, 30.4 months +/- 14.0). Rates of local tumor progression, overall survival, local progression-free survival, and event-free survival were evaluated by using the Kaplan-Meier method. RESULTS: The 1-, 2-, 3-, and 4-year rates of local tumor progression, overall survival, local progression-free survival, and recurrence-free survival were as follows: Local tumor progression rates were 14.4%, 17.6%, 17.6%, and 17.6%, respectively, in the combined treatment group and 11.4%, 14.4%, 14.4%, and 14.4%, respectively, in the radiofrequency ablation group (P = .797). Overall survival rates were 100%, 100%, 84.8%, and 72.7%, respectively, in the combined treatment group and 100%, 88.8%, 84.5%, and 74.0%, respectively, in the radiofrequency ablation group (P = .515). Local progression-free survival rates were 84.6%, 81.1%, 69.7%, and 55.8%, respectively, in the combined treatment group and 88.4%, 74.1%, 74.1%, and 61.7%, respectively, in the radiofrequency ablation group (P = .934). Event-free survival rates were 71.3%, 59.9%, 48.8%, and 36.6%, respectively, in the combined treatment group and 74.3%, 52.4%, 29.7%, and 29.7%, respectively, in the radiofrequency ablation group (P = .365). CONCLUSION: Combined radiofrequency ablation plus TACE and radiofrequency ablation alone have equivalent effectiveness for the treatment of small (< or =3 cm) HCCs, so the combination treatment may not be necessary.