18F-labeled PEGylated exendin-4 imaging noninvasively differentiates insulinoma from an accessory spleen: the first case report of [18F]FB(ePEG12)12-exendin-4 positron emission tomography/computed tomography for insulinoma.

Background: Insulinomas are the most common functioning pancreatic neuroendocrine neoplasms, and these tumors induce hypoglycemia due to hyperinsulinemia. Hypoglycemia caused by insulinomas can cause seizures, coma or death due to the delayed diagnosis. The only curative treatment is surgical resection. To perform curative surgical resection of insulinomas, preoperative localization is crucial. However, localization of insulinomas is often challenging using conventional imaging methods such as computed tomography (CT) and magnetic resonance imaging. Although endoscopic ultrasound (EUS) fine-needle aspiration and selective arterial calcium stimulation test, which can reflect the endocrine character of the tumor, are performed in such cases, these modalities are invasive and require operator-dependent techniques. Additionally, somatostatin receptor (SSTR)-targeted imaging has a relatively low sensitivity for detecting insulinomas due to its low SSTR type 2 expression. Thus, there is an urgent need for developing a noninvasive diagnostic technique which is specific for detecting insulinomas. Consequently, glucagon-like peptide-1 receptor-targeted imaging has recently emerged and gained a wide interest. Recently, we have developed a novel 18F-labeled exendin-4-based probe conjugated with polyethylene glycol, [18F]FB(ePEG12)12-exendin-4 (18F-exendin-4), for positron emission tomography (PET) imaging. Here we report a case of insulinoma in which 18F-exendin-4 PET/CT noninvasively provided critical information for localization. Case description: This is a case of a 58-year-old male with symptomatic hypoglycemia for 10 years; however, a preoperative diagnosis of insulinoma was not established due to the difficulty in differentiating it from an accessory spleen using conventional imaging. Moreover, the patient requested to avoid invasive diagnostic procedures including EUS. 18F-exendin-4 PET/CT revealed significant uptakes in the pancreatic tail whereas no apparent uptakes were observed in the spleen; thus, curative laparoscopic enucleation of the pancreatic tail was performed. The diagnosis of insulinoma was confirmed via histopathological examination. This is the first case report of insulinoma diagnosed using 18F-exendin-4 PET/CT. Conclusion: In this case, PET information led to curative resection through enucleation of the pancreas. 18F-exendin-4 PET/CT may serve as a useful noninvasive clinical tool for insulinoma localization.

Natural History of Hepatic Hemangiomas Larger Than 10 cm: Imaging Findings and Clinical Course of 22 Cases.

INTRODUCTION: The natural history of a large hepatic hemangioma is important in determining the treatment strategy. Although several studies have assessed the natural history of hepatic hemangiomas, no study has focused on hepatic hemangiomas measuring >10 cm. The aim of this study was to assess the natural history of hepatic hemangiomas measuring >10 cm by evaluating imaging findings and clinical course. METHODS: Computed tomography (CT) and magnetic resonance imaging (MRI) reports at Kyoto University Hospital, Kyoto, Japan, between January 2001 and March 2023 were retrospectively searched to find adult patients with hepatic hemangiomas >10 cm. Patients who were followed up without treatment for over six months were included. The maximum diameter of the hepatic hemangioma was compared between the baseline and the final CT or MRI. The clinical course of the patients was evaluated. RESULTS: Twenty-two patients (17 women, five men; median age, 51 years) were identified. The median diameter of hepatic hemangiomas in the baseline study was 114 mm. Two patients had abdominal distention at the time of the baseline imaging, whereas the others were asymptomatic. After follow-up without treatment (the median; 95.5 months), enlargement, no change, shrinkage of hepatic hemangioma was observed in six, 11, and five patients, respectively. The median growth rate of hepatic hemangiomas was 2.5 mm/year. Two patients underwent liver resection for hepatic hemangioma, while the others were followed up without treatment. In four patients, symptoms appeared or worsened. Two patients died: one patient died from prostate cancer progression; the cause of death for the other was not confirmed. CONCLUSION: Hepatic hemangiomas show a slow growth rate during follow-up, and shrinkage is occasionally observed. Some patients experience new symptoms or aggravation of symptoms; however, deaths associated with hepatic hemangiomas are uncommon.

Future liver remnant hypertrophy rate in portal vein embolization before left trisectionectomy: a retrospective cohort study.

PURPOSE: Reports on the future liver remnant (FLR) hypertrophy rate in patients undergoing portal vein embolization (PVE) before left trisectionectomy are sparse. This study aimed to assess the FLR hypertrophy rate in patients undergoing PVE before left trisectionectomy. METHODS: Between January 2010 and June 2021, 30 patients (22 men and eight women; mean age, 65.7 years) underwent PVE, mainly using gelatin sponge, before left trisectionectomy. The preoperative diagnosis was cholangiocarcinoma in 28 patients and colorectal liver metastases in two patients. The FLR hypertrophy rate, increase in the FLR volume (FLRV) ratio (the ratio of the FLRV to the total liver volume), and complications were evaluated. The patients were further divided into two groups: one group of patients with left portal vein stenosis or occlusion before PVE (n = 12) and another without left portal vein stenosis or occlusion before PVE (n = 18). The FLR hypertrophy rate and increase in the FLRV ratio were compared between the two groups. RESULTS: The FLR hypertrophy rate and increase in the FLRV ratio were 31.3% and 6.9%, respectively. One major complication, cholangitis, developed; however, its association with PVE was unclear. The difference in the FLR hypertrophy rate and the increase in the FLRV ratio between the two groups of patients was statistically insignificant. CONCLUSION: PVE before left trisectionectomy is effective in achieving FLR hypertrophy. PVE before left trisectionectomy was equally effective in patients with left portal vein stenosis or occlusion as compared to those without. The complication rates were acceptable.

Validation of the diagnostic utility of D-dimer measurement in patients with acute aortic syndrome.

OBJECTIVE: The objective of this study was to evaluate the validity of D-dimer measurements for the diagnosis of acute aortic syndrome in patients admitted to hospital with acute chest pain. METHODS: A retrospective observational study design was used. Consecutive patients ( n=887) admitted to a tertiary hospital with acute chest pain (acute aortic syndrome, 123; acute pulmonary embolism, 29; and other disease, 735) from the emergency department between January 2011 and April 2014 were assessed to validate the diagnostic value of D-dimer measurements. RESULTS: The D-dimer level was significantly increased in patients with acute aortic syndrome (median (interquartile range) 4.9 (2.0-17.4) µg/ml) compared with control patients (median (interquartile range) 0.6 (0.3-1.4) µg/ml; p<0.001). At a cut-off point of 0.5 µg/ml, the sensitivity for acute aortic syndrome was 0.97 (95% confidence interval 0.92-0.99) and was similar to that for acute pulmonary embolism (0.97 (0.82-0.99)). The age-adjusted D-dimer cut-off point, defined as age × 0.01 µg/ml in patients ⩾50 years, successfully reduced the number of false-positive diagnoses by 13%, while still retaining a high sensitivity (0.96 (0.91-0.99)). The five false-negative diagnoses of acute aortic syndrome included three patients with intramural haematoma, one patient with a penetrating aortic ulcer and one patient with an impending aortic rupture. A combination of probability assessment and the D-dimer approach reduced the number of false-negatives from five patients to two patients. CONCLUSIONS: This study demonstrated that the D-dimer test can distinguish acute aortic syndrome from other diseases presenting with acute chest pain with high sensitivity and modest specificity. Using the D-dimer approach presents limitations with some subtypes of acute aortic syndrome, such as intramural haematoma.

Contrast behavior of high-spatial-resolution T1-weighted MR imaging at 3.0 T vs. 1.5 T.

Twenty-four volunteers were examined at T1-weighted images with thin sections using gradient-based sequences with a possible short and same TR at 3.0 and 1.5 T. Pancreas-to-spleen contrast measurements and scores for visual assessments of image contrast were significantly worse at 3.0 T than at 1.5 T on both sequences. The image contrast of high-spatial-resolution T1-weighted images at 3.0 T is decreased compared to that of images with the same and possible short TR at 1.5 T.

Non-contrast-enhanced hepatic MR angiography: do two-dimensional parallel imaging and short tau inversion recovery methods shorten acquisition time without image quality deterioration?

OBJECTIVE: To study whether shortening the acquisition time for selective hepatic artery visualization is feasible without image quality deterioration by adopting two-dimensional (2D) parallel imaging (PI) and short tau inversion recovery (STIR) methods. MATERIALS AND METHODS: Twenty-four healthy volunteers were enrolled. 3D true steady-state free-precession imaging with a time spatial labeling inversion pulse was conducted using 1D or 2D-PI and fat suppression by chemical shift selective (CHESS) or STIR methods. Three groups of different scan conditions were assigned and compared: group A (1D-PI factor 2 and CHESS), group B (2D-PI factor 2×2 and CHESS), and group C (2D-PI factor 2×2 and STIR). The artery-to-liver contrast was quantified, and the quality of artery visualization and overall image quality were scored. RESULTS: The mean scan time was 9.5±1.0 min (mean±standard deviation), 5.9±0.8 min, and 5.8±0.5 min in groups A, B, and C, respectively, and was significantly shorter in groups B and C than in group A (P<0.01). The artery-to-liver contrast was significantly better in group C than in groups A and B (P<0.01). The scores for artery visualization and overall image quality were worse in group B than in groups A and C. The differences were statistically significant (P<0.05) regarding the arterial branches of segments 4 and 8. Between group A and group C, which had similar scores, there were no statistically significant differences. CONCLUSION: Shortening the acquisition time for selective hepatic artery visualization was feasible without deterioration of the image quality by the combination of 2D-PI and STIR methods. It will facilitate using non-contrast-enhanced MRA in clinical practice.

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.

Septic complication after balloon-occluded retrograde transvenous obliteration of duodenal variceal bleeding.

We report a 64-year-old woman with duodenal varices who underwent balloon-occluded retrograde transvenous obliteration (B-RTO) complicated by intraprocedural variceal rupture. The patient developed shivering and a fever higher than 40°C 3 days after the B-RTO procedure. A blood culture grew Entereobacter cloacoe. This case represents a rare septic complication of B-RTO for duodenal varices.

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.

Unenhanced MR portography with a half-Fourier fast spin-echo sequence and time-space labeling inversion pulses: preliminary results.

OBJECTIVE: For this study, we aimed to selectively visualize the intrahepatic portal veins using 3D half-Fourier fast spin-echo (FSE) MR angiography (MRA) with a time-space labeling inversion pulse (T-SLIP) and to optimize the acquisition protocol. SUBJECTS AND METHODS: Respiratory-triggered 3D half-Fourier FSE scans were obtained in 25 healthy adult subjects combined with two different T-SLIPs: one placed on the liver and the thorax to suppress signals of the liver parenchyma, hepatic veins, and abdominal arteries and the other on the lower abdomen to suppress the ascending signal of the inferior vena cava. One of the most important factors was the inversion time (TI) of the inversion pulse for the liver and thorax. Image quality was evaluated in terms of signal-to-noise ratio, contrast-to-noise ratio, and mean visualization scores at four different TIs: 800, 1,200, 1,600, and 2,000 milliseconds. RESULTS: Selective visualization of the portal vein was successfully achieved in all volunteers, and anatomic variations were also seen in three subjects. A TI of 1,200 milliseconds was optimal in our protocol because it was sufficient for peripheral portal vein visualization and was most suitable for signal suppression of the hepatic veins and liver parenchyma. CONCLUSION: Half-Fourier FSE scanning with T-SLIPs enabled selective visualization of the portal vein without an exogenous contrast agent.

Non-contrast-enhanced MR portography with time-spatial labeling inversion pulses: comparison of imaging with three-dimensional half-fourier fast spin-echo and true steady-state free-precession sequences.

PURPOSE: To compare and evaluate images acquired with two different MR angiography (MRA) sequences, three-dimensional (3D) half-Fourier fast spin-echo (FSE) and 3D true steady-state free-precession (SSFP) combined with two time-spatial labeling inversion pulses (T-SLIPs), for selective and non-contrast-enhanced (non-CE) visualization of the portal vein. MATERIALS AND METHODS: Twenty healthy volunteers were examined using half-Fourier FSE and true SSFP sequences on a 1.5T MRI system with two T-SLIPs, one placed on the liver and thorax, and the other on the lower abdomen. For quantitative analysis, vessel-to-liver contrast (Cv-l) ratios of the main portal vein (MPV), right portal vein (RPV), and left portal vein (LPV) were measured. The quality of visualization was also evaluated. RESULTS: In both pulse sequences, selective visualization of the portal vein was successfully conducted in all 20 volunteers. Quantitative evaluation showed significantly better Cv-l at the RPVs and LPVs in half-Fourier FSE (P < 0.0001). At the MPV, Cv-l was better in true SSFP, but was not statistically different. Visualization scores were significantly better only at branches of segments four and eight for half-Fourier FSE (P = 0.001 and 0.03, respectively). CONCLUSION: Both 3D half-Fourier FSE and true SSFP scans with T-SLIPs enabled selective non-CE visualization of the portal vein. Half-Fourier FSE was considered appropriate for intrahepatic portal vein visualization, and true SSFP may be preferable when visualization of the MPV is required.

Hepatic lesions: improved image quality and detection with the periodically rotated overlapping parallel lines with enhanced reconstruction technique--evaluation of SPIO-enhanced T2-weighted MR images.

PURPOSE: To evaluate the effectiveness of the periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) technique for superparamagnetic iron oxide (SPIO)-enhanced T2-weighted magnetic resonance (MR) imaging with respiratory compensation with the prospective acquisition correction (PACE) technique in the detection of hepatic lesions. MATERIALS AND METHODS: The institutional human research committee approved this prospective study, and all patients provided written informed consent. Eighty-one patients (mean age, 58 years) underwent hepatic 1.5-T MR imaging. Fat-saturated T2-weighted turbo spin-echo images were acquired with the PACE technique and with and without the PROPELLER method after administration of SPIO. Images were qualitatively evaluated for image artifacts, depiction of liver edge and intrahepatic vessels, overall image quality, and presence of lesions. Three radiologists independently assessed these characteristics with a five-point confidence scale. Diagnostic performance was assessed with receiver operating characteristic (ROC) curve analysis. Quantitative analysis was conducted by measuring the liver signal-to-noise ratio (SNR) and the lesion-to-liver contrast-to-noise ratio (CNR). The Wilcoxon signed rank test and two-tailed Student t test were used, and P < .05 indicated a significant difference. RESULTS: MR imaging with the PROPELLER and PACE techniques resulted in significantly improved image quality, higher sensitivity, and greater area under the ROC curve for hepatic lesion detection than did MR imaging with the PACE technique alone (P < .001). The mean liver SNR and the lesion-to-liver CNR were higher with the PROPELLER technique than without it (P < .001). CONCLUSION: T2-weighted MR imaging with the PROPELLER and PACE technique and SPIO enhancement is a promising method with which to improve the detection of hepatic lesions. (c) RSNA, 2009.

Non-contrast-enhanced MR angiography for selective visualization of the hepatic vein and inferior vena cava with true steady-state free-precession sequence and time-spatial labeling inversion pulses: preliminary results.

PURPOSE: To selectively visualize the hepatic vein and inferior vena cava (IVC) using three-dimensional (3D) true steady-state free-precession (SSFP) MR angiography with time-spatial labeling inversion pulse (T-SLIP), and to optimize the acquisition protocol. MATERIALS AND METHODS: Respiratory-gated 3D true SSFP scans were conducted in 23 subjects in combination with two different T-SLIPs (one placed in the thorax to suppress the arterial signal and the other in the abdomen to suppress the portal venous signal). One of the most important factors was the inversion time (TI) of abdominal T-SLIP, and the image quality was evaluated at four different TIs of 800, 1200, 1600, and 2000 msec in terms of relative signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and mean visualization scores. RESULTS: No significant difference was observed in SNR and CNR between each TI. However, IVC visualization scores were better at TIs of 1600 and 2000 msec, and overall image quality was better at TIs of 1200 and 1600 msec. Therefore, the TI of 1600 msec was considered to provide the optimal balance between IVC visualization and signal suppression of the portal vein in our protocol. CONCLUSION: True SSFP scan with T-SLIPs enabled selective visualization of the hepatic vein and IVC without an exogenous contrast agent.

Non-contrast-enhanced hepatic MR angiography with true steady-state free-precession and time spatial labeling inversion pulse: optimization of the technique and preliminary results.

OBJECTIVE: To selectively visualize the hepatic arteries using the respiratory-triggered three-dimensional (3D) true steady-state free-precession (SSFP) projection magnetic resonance angiographic sequence with time spatial labeling inversion pulse (T-SLIP), and describe the optimization of this protocol. MATERIALS AND METHODS: Twenty healthy volunteers were examined in this study. A respiratory-triggered 3D true SSFP combined with T-SLIP was performed. Among several key factors that affect the image quality, the most important is the inversion time (TI). Therefore, according to the difference in TI, four image groups: group A (TI of 800 ms), group B (TI of 1000 ms), group C (TI of 1200 ms), and group D (TI of 1400 ms), were assigned and compared to detect the optimal TI for hepatic artery visualization. For quantitative assessment, the relative signal intensity, i.e., Cv-l (vessel-to-liver contrast) of the right hepatic artery was measured. For qualitative evaluation, the quality of vessel visualization and the order of identified hepatic artery branches were evaluated by two radiologists. RESULTS: Selective and high-contrast visualization of the hepatic arteries was acquired in all cases. Regarding the quantitative assessment, Cv-l decreased in group D due to background signal recovery, but there was no significant difference between groups (p-value >0.05). Regarding the qualitative evaluation, there were significant differences between group A and the other groups (p-value <0.01) and between groups B and C (p-value <0.05). In group C, both the image quality score and mean value for the order of the hepatic artery branches were highest, and a TI of 1200 ms was thought to be optimal regarding the balance between vessel-to-liver contrast and peripheral hepatic artery visualization. CONCLUSION: The MR angiographic technique using true SSFP with T-SLIP enabled the selective visualization of hepatic arteries without the need for an exogenous contrast agent or breath-hold.

F-18 fluorodeoxyglucose uptake in a solid pseudopapillary tumor of the pancreas mimicking malignancy.

Solid pseudopapillary tumors (SPTs), predominantly affecting young women, are rare pancreatic tumors. It is reported that imaging features of SPT are solid and cystic components, and there is intratumoral hemorrhage and calcification. However, findings of positron emission tomography (PET) using F-18 fluorodeoxyglucose (FDG) with pathologic correlation have not been fully evaluated. We present a case of SPT that mimicked malignancy on FDG-PET.

MRI artifact reduction and quality improvement in the upper abdomen with PROPELLER and prospective acquisition correction (PACE) technique.

OBJECTIVE: The purpose of this study was to evaluate the effectiveness of the periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER [BLADE in the MR systems from Siemens Medical Solutions]) with a respiratory compensation technique for motion correction, image noise reduction, improved sharpness of liver edge, and image quality of the upper abdomen. SUBJECTS AND METHODS: Twenty healthy adult volunteers with a mean age of 28 years (age range, 23-42 years) underwent upper abdominal MRI with a 1.5-T scanner. For each subject, fat-saturated T2-weighted turbo spin-echo (TSE) sequences with respiratory compensation (prospective acquisition correction [PACE]) were performed with and without the BLADE technique. Ghosting artifact, artifacts except ghosting artifact such as respiratory motion and bowel movement, sharpness of liver edge, image noise, and overall image quality were evaluated visually by three radiologists using a 5-point scale for qualitative analysis. The Wilcoxon's signed rank test was used to determine whether a significant difference existed between images with and without BLADE. A p value less than 0.05 was considered to be statistically significant. RESULTS: In the BLADE images, image artifacts, sharpness of liver edge, image noise, and overall image quality were significantly improved (p < 0.001). CONCLUSION: With the BLADE technique, T2-weighted TSE images of the upper abdomen could provide reduced image artifacts including ghosting artifact and image noise and provide better image quality.

Contrast behavior and image quality of magnetic resonance cholangiopancreatography imaging using variable echo times at 3.0 T.

Twenty-five volunteers were examined at three different echo times (TE) using magnetic resonance cholangiopancreatography (MRCP) images obtained with half-Fourier-acquired single-shot turbo spin echo (HASTE) thick-slab and multislice HASTE to identify the optimal TE at 3.0 T. No significant difference in the overall image quality was found comparing three different TEs within commonly used ranges. We observed an almost identical duct visibility with different TEs, while we found a trend toward superior visibility of the cystic duct at shorter TE.