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Objective: To investigate whether balloon-occluded transcatheter arterial chemoembolization (b-TACE) can produce a more dense accumulation of iodized oil in various stages of hepatocellular carcinoma (HCC), from single to uncountable, to overcome inferior local control. Materials and Methods: We studied 27 patients with HCC, including single to uncountable multiple lesions, who underwent b-TACE between August 2013 and April 2015. Dynamic CT was performed at baseline and 1-3 months after b-TACE. The treatment effect (TE) after b-TACE was evaluated using the Response Evaluation Criteria in Cancer of the Liver (RECICL) proposed by the Liver Cancer Study Group of Japan. Results: In the countable HCC group, contrast-enhanced CT demonstrated RECICL TE4 in 43.8% (14/32), TE3 in 12.5% (4/32), TE2 in 37.5% (12/32), and TE1 in 6.3% (2/32) of patients. For the TACE-naïve cohort, the objective response rate was 52.9%. The objective response rate was 60% for the previously TACE-treated cohort. In the uncountable multiple HCC group, the objective response rate was 0% (0/10), with progressive disease in 90% (9/10) of patients. Conclusion: Our observations suggested that b-TACE did not reduce the efficacy of retreatment for HCC with an insufficient outcome from conventional TACE, but it could not improve the efficacy of treatment for uncountable multiple HCCs. © 2015 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: A new multiphasic fast imaging technique, known as volume helical shuttle technique, is a breakthrough for liver imaging that offers new clinical opportunities in dynamic blood flow studies. This technique enables virtually real-time hemodynamics assessment by shuttling the patient cradle back and forth during serial scanning. Purpose: To determine optimal scan timing of hepatic arterial-phase imaging for detecting hypervascular hepatocellular carcinoma (HCC) with maximum tumor-to-liver contrast by volume helical shuttle technique. Material and Methods: One hundred and one hypervascular HCCs in 50 patients were prospectively studied by 64-channel multidetector-row computed tomography (MDCT) with multiphasic fast imaging technique. Contrast medium containing 600 mg iodine per kg body weight was intravenously injected for 30 s. Six seconds after the contrast arrival in the abdominal aorta detected with bolus tracking, serial 12-phase imaging of the whole liver was performed during 24-s breath-holding with multiphasic fast imaging technique during arterial phase. By placing regions of interest in the abdominal aorta, portal vein, liver parenchyma, and hypervascular HCCs on the multiphase images, time-density curves of anatomical regions and HCCs were composed. Timing of maximum tumor-to-liver contrast after the contrast arrival in the abdominal aorta was determined. Results: For the detection of hypervascular HCC at arterial phase, mean time and value of maximum tumor-to-liver contrast after the contrast arrival were 21 s and 38.0 HU, respectively. Conclusion: Optimal delay time for the hepatic arterial-phase imaging maximizing the contrast enhancement of hypervascular HCCs was 21 s after arrival of contrast medium in the abdominal aorta. [ABSTRACT FROM AUTHOR]

We have occasionally seen ring-shaped lateral ventricular nodules <1 cm in diameter during routine brain magnetic resonance imaging (MRI). We investigated retrospectively clinical and MRI findings of the nodules. Review of radiological records was performed for 39,607 patients who underwent brain MRI between January 2001 and April 2008. Nodules were assessed for number, location, shape, and signal intensity, which was determined based on the range of signal intensity from gray to white matter on T1- and T2-weighted imaging. Fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted imaging (DWI), contrast enhancement characteristics, and serial MRI changes of nodules were assessed when available. Nine of 39,607 patients (0.023%) showed the nodules. No symptoms associated with the nodules. Among the nine patients, 11 nodules were identified (one nodule in seven patients (77.8%) and two nodules in two patients (22.2%)). Location was limited to the roof of the body for six nodules (54.5%) and the frontal horn for five patients (45.5%). All nodules (100%) were round and isointense on T1- and T2-weighted imaging. On FLAIR imaging of eight nodules, six (75%) were hyperintense, and two (25%) were isointense. On DWI of seven nodules, all nodules (100%) were isointense. None of seven nodules (0%) examined using postcontrast MRI showed enhancement. None of eight nodules (0%) examined using serial MRI (range, 4–60 months) showed changes in morphology over time. These nodules were incidentally encountered and shared similar MRI features. Although pathological confirmation was lacking in our cases, these nodules may be of nonaggressive nature. [ABSTRACT FROM AUTHOR]

Simple Summary: Recent advances in fusion imaging technology have made it easier to visualize and estimate ablative margins. This study was conducted to assess the clinical feasibility of a computed tomography (CT)/magnetic resonance imaging (MRI) fusion application for evaluation of the ablative margin in radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC). Seventeen patients developed local tumor progressions (LTPs) due to wrong initial evaluations of technical success through a side-by-side comparison, and we reevaluated the ablative margins using the CT/MRI overlay fusion application. Eight patients were categorized into grade C (margin-zero ablation) and nine patients into grade D (existence of residual HCC). LTP occurred in re-graded C patients within 4 to 30.3 months (median, 14.3 months), and in re-graded D patients within 2.4 to 6.7 months (median, 4.2 months) (p = 0.006). Overlay fused CT/MRI imaging can allow us to evaluate HCC ablative margin three-dimensionally with high accuracy. Background: We investigate the feasibility of image fusion application for ablative margin assessment in radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC) and possible causes for a wrong initial evaluation of technical success through a side-by-side comparison. Methods: A total of 467 patients with 1100 HCCs who underwent RFA were reviewed retrospectively. Seventeen patients developed local tumor progressions (LTPs) (median size, 1.0 cm) despite initial judgments of successful ablation referring to contrast-enhanced images obtained in the 24 h after ablation. The ablative margins were reevaluated radiologically by overlaying fused images pre- and post-ablation. Results: The initial categorizations of the 17 LTPs had been grade A (absolutely curative) (n = 5) and grade B (relatively curative) (n = 12); however, the reevaluation altered the response categories to eight grade C (margin-zero ablation) and nine grade D (existence of residual HCC). LTP occurred in eight patients re-graded as C within 4 to 30.3 months (median, 14.3) and in nine patients re-graded as D within 2.4 to 6.7 months (median, 4.2) (p = 0.006). Periablational hyperemia enhancements concealed all nine HCCs reevaluated as grade D. Conclusion: Side-by-side comparisons carry a risk of misleading diagnoses for LTP of HCC. Overlay fused imaging technology can be used to evaluate HCC ablative margin with high accuracy. [ABSTRACT FROM AUTHOR]

Simple Summary: Transcatheter arterial embolization (TAE) with coils is widely used to treat pseudoaneurysms; recently, the use of N-butyl cyanoacrylate (NBCA) in TAE has been reported as a feasible and effective approach. The purpose of our retrospective study was to evaluate the efficacy and safety of TAE with coils and NBCA for pseudoaneurysms associated with pancreatitis or pancreatic surgery. This retrospective study included 42 consecutive patients. The technical and clinical success rates, incidence of recurrent bleeding, complications, including pancreatitis, and overall survival after TAE were evaluated. All cases obtained hemostasis after TAE (the technical success rate was 100%). Complications were seen in only two patients. Clinical success rate that was evaluated in terms of 30-day mortality was 76.2%. TAE is then an effective treatment modality for pseudoaneurysms associated with pancreatitis or pancreatic surgery. Accurate diagnosis using angiography contributes to the proper choice of embolic agents and management of such hemorrhages. Purpose: To evaluate the efficacy and safety of transcatheter arterial embolization (TAE) for pseudoaneurysms occurring secondary to pancreatitis or because of leakage of pancreatic juice after pancreatectomy. Materials and Methods: This retrospective study included 42 consecutive patients (38 males and 4 females; mean age, 60 years; range, 33–80 years) who underwent TAE for bleeding visceral artery pseudoaneurysms between March 2004 and December 2018. The technical and clinical success rates, incidence of recurrent bleeding, complications, including pancreatitis, and overall survival after TAE were evaluated. Results: Of the 42 enrolled patients, 23 had bleeding due to a complication of pancreatectomy and 19 had bleeding as a complication of pancreatitis. TAE with N-butyl cyanoacrylate (NBCA) or NBCA plus microcoils recurrent bleeding or inability to control bleeding was 15.8% (3 of 19) following TAE with NBCA and 17.4% (4 of 23) following TAE with coils. No clinically significant ischemic events of the pancreas or duodenum were observed in the embolized areas. Serum amylase did not increase compared with the initial levels after any of the procedures. At 30 days after TAE, 32 patients were alive. Conclusion: TAE has a high success rate for the management of hemorrhage, with few complications. The procedure appears to be safe and effective for pseudoaneurysms associated with either pancreatitis or pancreatectomy. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the impact of radiologic experience on the diagnostic accuracy of computed tomography (CT) vs. magnetic resonance imaging (MRI) reporting on the liver metastases of pancreatic ductal adenocarcinoma (LM of PDAC). Intra-individual CT and MRI examinations of 112 patients with clinically proven LM of PDAC were included. Four radiologists with varying years of experience (A > 20, B > 5, C > 1 and D < 1) assessed liver segments affected by LM of PDAC, as well as associated metastases occurring in each patient. Their sensitivity and specificity in evaluating the segments were compared. Cohen's Kappa (κ) for diagnosed liver segments and Intra-class Correlation Coefficients (ICC) for the number of metastatic lesions in each patient were calculated. The radiologists' sensitivity and specificity for the CT vs. MRI were, respectively: Reader A—94.4%, 90.3% vs. 96.6%, 94.8%; B—86.7%, 79.7% vs. 83.9%, 82.0%; C—78.0%, 76.7% vs. 83.3%, 78.9% and D—71.8%, 79.2% vs. 64.0%, 69.5%. Reviewers A and B achieved greater agreement in assessing results from the MRI (κ = 0.72, p < 0.001; ICC = 0.73, p < 0.001) vs. the CT (κ = 0.58, p < 0.001; ICC = 0.61, p < 0.001), in contrast to readers C and D (MRI: κ = 0.34, p < 0.001; ICC = 0.42, p < 0.001, and CT: κ = 0.48, p < 0.001; ICC = 0.59, p < 0.001). Our results indicate that the accurate diagnosis of LM of PDAC depends more on radiologic experience in MRI over CT scans. [ABSTRACT FROM AUTHOR]

To report MRI findings of spontaneous infarction in parotid tumours. 14 patients (13 male, 1 female; mean age 73 years) with spontaneously infarcted parotid tumours were reviewed retrospectively. MR images were assessed for the location, the presence of synchronous parotid masses, margin characteristics, signal intensity on T1 and T2 weighted images, and internal architecture according to the distribution of T2 signal hyperintensity. 12 tumours were located in the parotid tail and 2 in the superficial lobe. Synchronous parotid masses were seen in four tumours, three of which were located in the ipsilateral parotid tail and one in the contralateral parotid tail. Seven tumours had well-defined margins and seven had ill-defined margins. The signal intensities on T1 weighted images were a mixture of high and intermediate in all cases; in 11 tumours, hyperintense areas were dominant. On T2 weighted images, all tumours also showed a mixture of high and intermediate signal intensities. Internal architectures on T2 weighted images were mosaic hyperintensity in three tumours, central hyperintensity in five, and multiseparated hyperintensity in six. Spontaneously infarcted parotid tumours were mostly located in the parotid tail and showed mixed signal intensities with predominant hyperintensity on T1 weighted images. Half of the tumours had ill-defined margins, and the internal architectures varied. [ABSTRACT FROM AUTHOR]

To devise a simple new technique wherein absolute ethanol is injected via a sheath under proximal balloon occlusion of the right portal vein using a single-balloon catheter and to examine its feasibility and safety for ipsilateral portal vein embolization (PVE). Between 2010 and 2016, PVE was performed in 19 patients prior to undergoing extended right hepatectomy. PVE was performed via a percutaneous transhepatic ipsilateral approach, the right portal branch was embolized under ultrasound guidance, and a balloon catheter was placed in the proximal site of the main right portal branch. Absolute ethanol was injected through a sheath under proximal balloon occlusion of the right portal vein using a double-lumen catheter. We evaluated its technical success and complications following PVE and changes in liver enzyme levels. Furthermore, we calculated changes in future liver remnant (FLR) and FLR/total functional liver volume (TFLV) ratio and assessed complications following hepatic resection. PVE was successfully performed in all patients. Mean FLR and FLR/TFLV significantly increased following PVE (p < 0.01). The change in the FLR and FLR/TFLV ratio was 39.6 ± 16.2%. One patient (6.5%) developed procedure-related complications following PVE (perihepatic hematoma). The new technique for ipsilateral right PVE is safe, effective, and convenient. This is the first study to investigate the efficacy of injecting ethanol via a sheath under proximal balloon occlusion of the right portal vein using a single-balloon catheter. [ABSTRACT FROM AUTHOR]

To report MR imaging features of mammary analogue secretory carcinoma (MASC) and acinic cell carcinoma (AciCC) of the salivary gland based on the latest version of the World Health Organization (WHO) 2017 classification of head and neck tumours. MR images in 4 patients with MASC and 4 with AciCC were reviewed for margin characteristics, the presence of pathological cervical nodes, the presence of a cystic component and interface between cystic and solid component, signal intensity of the cystic components on T1 weighted images, and signal intensity of the solid component on T1 and T2 weighted images. All the MASCs and AciCCs had well-defined boundaries, and 1 AciCC had pathological nodes. All 4 MASCs presented as predominantly cystic tumours with papillary projection of the solid component. All 4 AciCCs presented as solid tumours. The signal intensity of the cystic components on T1 weighted images was entirely hyperintense in 2, and partly hyperintense demonstrating fluid–fluid level in 2. In all the MASCs, the signal intensity of the solid components on T1 weighted images was intermediate. In the AciCCs, the signal intensity of the solid components on T1 weighted images was high in 2 tumours and intermediate in 2. The signal intensity of the solid components on T2 weighted images varied from low to high in both MSACs and AciCCs. All 4 MASCs had a large cystic component, including areas of high signal intensity on T1 weighted images. The solid component appeared as a papillary projection into the cystic component. All 4 AciCCs presented as solid tumours, 2 of which showed high signal intensity on T1 weighted images. [ABSTRACT FROM AUTHOR]

Objective: To report clinical features of bone metastases (BM) from head and neck squamous cell carcinoma (HNSCC).Methods: Among 772 patients with HNSCC diagnosed at our hospital over 9 years, 30 patients (3.9%) had clinical evidence of BM (24 men and 6 women; mean age: 63 years). We assessed the time interval from the primary diagnosis to BM development, symptoms attributable to BM, presence of distant metastases to other organs, number of BM, sites of BM, morphologic changes on computed tomography (CT) images, treatment for BM, and overall survival (OS).Results: BM at the initial stage were found in 9 patients with HNSCC (30%), and in 21 patients (70%) with HNSCC during the course of the disease. In the later patients, the median time interval from the primary diagnosis was 11.5 months. Nineteen patients (63%) did not have BM-related symptoms, 6 (20%) had pain, 3 (10%) had neurologic symptoms resulting from vertebral or skull metastases, and 2 (7%) had hypercalcemia. Seventeen patients (57%) showed bone-exclusive metastases, and 13 (43%) had distant metastases in other organs. Eleven patients (37%) had monostotic metastases (solitary BM), and 19 patients (63%) had polyostotic metastases (multiple BM). When combined, 9 patients (30%) showed bone-exclusive and monostotic metastases. The most commonly affected site was the thoracolumbar spine, accounting for 34% of total BM, followed by the pelvis (24%), shoulder and thorax (21%), and the extremities (17%). Notably, metastases to bones above the clavicle (craniofacial bones and cervical spine) accounted for only 3% of all bone lesions. CT images showed variable morphologic patterns with osteolytic type in 17 patients (57%), intertrabecular in 7 (23%), osteoblastic in 4 (13%), and mixed in 2 (7%). Systematic chemotherapy for BM was performed in 19 patients and radiotherapy in 18. The median survival time for patients with bone-exclusive and monostotic metastases was significantly longer than that for patients with multi-organ metastases or polyostotic metastases at 18.2 months vs. 5.7 months (p=0.02). Neither chemotherapy nor radiotherapy extended OS.Conclusion: Thirty percent of BM cases from HNSCC showed bone-exclusive and monostotic metastases. These patients tended to show a more favorable prognosis than patients with multi-organ metastases or polyostotic metastases. [ABSTRACT FROM AUTHOR]

Objectives: To report MRI findings of spontaneous infarction in parotid tumours., Methods: 14 patients (13 male, 1 female; mean age 73 years) with spontaneously infarcted parotid tumours were reviewed retrospectively. MR images were assessed for the location, the presence of synchronous parotid masses, margin characteristics, signal intensity on T 1 and T 2 weighted images, and internal architecture according to the distribution of T 2 signal hyperintensity., Results: 12 tumours were located in the parotid tail and 2 in the superficial lobe. Synchronous parotid masses were seen in four tumours, three of which were located in the ipsilateral parotid tail and one in the contralateral parotid tail. Seven tumours had well-defined margins and seven had ill-defined margins. The signal intensities on T 1 weighted images were a mixture of high and intermediate in all cases; in 11 tumours, hyperintense areas were dominant. On T 2 weighted images, all tumours also showed a mixture of high and intermediate signal intensities. Internal architectures on T 2 weighted images were mosaic hyperintensity in three tumours, central hyperintensity in five, and multiseparated hyperintensity in six., Conclusions: Spontaneously infarcted parotid tumours were mostly located in the parotid tail and showed mixed signal intensities with predominant hyperintensity on T 1 weighted images. Half of the tumours had ill-defined margins, and the internal architectures varied.

Objectives: To report MR imaging features of mammary analogue secretory carcinoma (MASC) and acinic cell carcinoma (AciCC) of the salivary gland based on the latest version of the World Health Organization (WHO) 2017 classification of head and neck tumours., Methods: MR images in 4 patients with MASC and 4 with AciCC were reviewed for margin characteristics, the presence of pathological cervical nodes, the presence of a cystic component and interface between cystic and solid component, signal intensity of the cystic components on T 1  weighted images, and signal intensity of the solid component on T 1 and T 2  weighted images., Results: All the MASCs and AciCCs had well-defined boundaries, and 1 AciCC had pathological nodes. All 4 MASCs presented as predominantly cystic tumours with papillary projection of the solid component. All 4 AciCCs presented as solid tumours. The signal intensity of the cystic components on T 1  weighted images was entirely hyperintense in 2, and partly hyperintense demonstrating fluid-fluid level in 2. In all the MASCs, the signal intensity of the solid components on T 1  weighted images was intermediate. In the AciCCs, the signal intensity of the solid components on T 1  weighted images was high in 2 tumours and intermediate in 2. The signal intensity of the solid components on T 2  weighted images varied from low to high in both MSACs and AciCCs., Conclusions: All 4 MASCs had a large cystic component, including areas of high signal intensity on T 1  weighted images. The solid component appeared as a papillary projection into the cystic component. All 4 AciCCs presented as solid tumours, 2 of which showed high signal intensity on T 1  weighted images.

Using 11C-Pittsburgh compound B (PiB)-PET and MRI volume data, we investigated whether white matter (WM) PiB uptake in Alzheimer's disease (AD) brain is larger than that of cortical PiB uptake-negative (PiB-negative) brain. Forty-five subjects who underwent both PiB-PET and MRI were included in the study (32 AD patients with cortical PiB-positive and 13 cortical amyloid -negative patients). Individual areas of gray matter (GM) and WM were segmented, then regional GM and WM standard uptake value ratio (SUVR) normalized to cerebellar GM with partial volume effects correction was calculated. Three regional SUVRs except WM in the centrum semiovale in the AD group were significantly larger than those in the PiB-negative groups. Frontal WM SUVR in the AD group vs frontal WM SUVR in the PiB-negative group was 2.57 ± 0.55 vs 1.64 ± 0.22; parietal, 2.50 ± 0.52 vs 1.74 ± 0.22; posterior cingulate, 2.84 ± 0.59 vs 1.73 ± 0.22; and WM in the centrum semiovale, 2.21 ± 0.53 vs 2.42 ± 0.36, respectively. We found that PiB uptake in AD brain is significantly larger than that in PiB-negative brain in the frontal, parietal and posterior cingulate subcortical WM, except in the centrum semiovale.

Giant cell tumor of bone (GCTB) is commonly treated with surgery; however, surgery of GCTB in the sacrum may be challenging due to the associated risk. A conservative approach may be selective arterial embolization or zoledronic acid (ZOL) treatment; however, there are currently no studies investigating the efficacy of combining these two treatments. Denosumab may also be used; however, to the best of our knowledge, there are no reports of a stepwise approach for the use of all three treatments in a single patient. We herein present such a case. A 32-year-old woman diagnosed with sacral GCTB was treated with selective arterial embolization for 3 months. No improvement was observed, and monthly infusions of ZOL were added (administered 2 weeks after each arterial embolization treatment). Ten months after the initiation of ZOL, there was still no improvement. The therapy was changed to denosumab 120 mg, injected subcutaneously once a month. By the third dose, the buttock pain had decreased and the patient became ambulatory. At 5 and 10 months, computed tomography scans revealed bone sclerosis gradually appearing around the sacrum. By 1 year, needle biopsy detected no neoplastic cells. At that point, the patient discontinued treatment, as there was hepatic function impairment due to a history of hepatitis B. Despite treatment discontinuation, the patient exhibited no further symptoms, there were no signs of progression on radiography, and surgery was not required. Our patient experienced treatment failure with selective arterial embolization. The combination of ZOL with selective arterial embolization also did not improve the patient's condition. Denosumab was found to be superior to both treatments, achieving tumor remission. The patient remains symptom- and disease-free. Further studies are required, but our results suggest that patients with unresectable GCTB who fail to respond to selective arterial embolization may benefit from denosumab treatment, but not from combination therapy with selective arterial embolization and ZOL.

Purpose: New tracking navigation imaging software was used to evaluate the usefulness of three dimensional (3D) CT angiography for transcatheter arterial chemoembolization (TACE) in patients with hepatocellular carcinoma (HCC)., Materials and Methods: Fifty-two patients with 73 HCCs were enrolled in this study retrospectively. Rotational angiography was performed from the hepatic artery for evaluation of the tumor feeding vessels. Arteries feeding the tumor were traced automatically by adjusting the region of interest around the targeted tumor on axial and coronal images using tracking navigation imaging with 3D cone-beam CT angiography., Results: Using final selective angiographic findings as the gold standard, the detection of feeding vessels was 90.4% (66/73) for tracking navigation imaging and 50.7% (37/73) for celiac trunk angiography. This difference was statistically significant (Wilcoxon rank sum test, p < 0.001). The sensitivity, specificity, positive predictive value, and negative predictive value for the detection of feeding arteries were 97.1% (66/68), 80.0% (4/5), 98.5% (66/67), and 66.7% (4/6), respectively. The kappa coefficient had a value of 0.638 (95% CI: 0.471-0.805), which is considered to indicate a good degree of agreement. With the assistance of tracking navigation imaging, the disease control rate of TACE for HCC was 67.3% (35/52) according to the modified Response Evaluation Criteria in Solid Tumors. During follow-up periods of 1-11 months, 10 patients (19.2%) remained cancer-free after TACE., Conclusion: Tracking navigation imaging with 3D cone-beam CT angiography should be useful for TACE in HCC patients with complicated feeding arteries.

Objective: The purpose of this study was to evaluate the effectiveness of contrast harmonic sonographic guidance in radiofrequency ablation of locally progressive hepatocellular carcinoma poorly depicted with B-mode sonography., Subjects and Methods: A series of 40 patients with hepatocellular carcinoma with local tumor progression poorly depicted with B-mode sonography were randomly treated with radiofrequency ablation guided by either contrast harmonic sonography (n = 20) or conventional B-mode sonography (n = 20). Unpaired Student's t tests were performed to compare numbers of treatment sessions., Results: Treatment analysis showed that the complete ablation rate after a single treatment session was significantly higher in the contrast harmonic sonography group than in the B-mode sonography group (94.7% vs 65.0%; p = 0.043) and that the number of treatment sessions was significantly lower in the contrast harmonic sonography group (mean, 1.1 +/- 0.2 vs 1.4 +/- 0.6; p =0.037)., Conclusion: Contrast harmonic sonography-guided radiofrequency ablation is an efficient technique for guiding further ablation of local tumor progression not clearly demarcated with B-mode sonography.

Objective: The objective of our study was to investigate the effect of different iodine concentrations in contrast materials on the depiction of hypervascular hepatocellular carcinomas (HCCs) by MDCT., Subjects and Methods: This prospective study involved 100 consecutive patients with chronic liver disease, including 27 patients with hypervascular HCCs. The first 50 patients received 100 mL of iopamidol at a concentration of 370 mg I/mL (group A) and the subsequent 50, 100 mL at 300 mg I/mL (group B); in both groups, the contrast material was administered at a rate of 3.0 mL/sec. Unenhanced scanning and four-phase enhanced scanning at 25, 40, 60, and 180 sec after the start of contrast injection were performed. The enhancement of the aorta, liver, and portal vein was measured during each phase. In addition, tumor-to-liver contrast was calculated for the 27 patients with hypervascular HCCs. Of the 27 patients with hypervascular HCCs, 15 were in group A and 12 were in group B., Results: During all phases, aortic enhancement was significantly greater in group A than group B (p < 0.01). Hepatic enhancement was significantly greater in group A than group B at 60 and 180 sec (both p < 0.01). There was no significant difference in hepatic enhancement between the two groups at 25 and 40 sec. Tumor-to-liver contrast was significantly greater in group A than group B during the late arterial phase (40 sec, p = 0.02), although there was no significant difference at 25, 60, and 180 sec., Conclusion: Contrast materials with higher iodine concentration are more effective for depicting hypervascular HCCs on MDCT during the late arterial phase.

Purpose: To prospectively evaluate aortic and hepatic enhancement and depiction of hypervascular hepatocellular carcinoma (HCC) between two contrast materials with moderate and high iodine concentrations when administered at same iodine dose and injection duration at multi-detector row helical computed tomography (CT)., Materials and Methods: Institutional review board approval and informed patient consent were obtained. One hundred eighty-six patients were studied, and 67 patients with hypervascular HCC were identified. Ninety-four patients were assigned to receive iohexol 350 (mg iodine per milliliter) with protocol A; 92, iohexol 300 with protocol B. In both protocols, iohexol with same iodine load per weight (518 mg/kg) was administered with same injection duration (25 seconds). Multiphase CT scanning was started 10, 20, 50, and 180 seconds after the trigger (threshold level set at increase of 100 HU over baseline CT number of aorta). Enhancement of aorta and liver was measured in 186 patients. Tumor-to-liver contrast was measured in 67 patients with hypervascular HCC. Statistical analysis was performed with Mann-Whitney U test., Results: Medians of aortic enhancement during four phases were 325, 185, 112, and 69 HU with protocol A. Corresponding values were 344, 266, 121, and 73 HU with protocol B. During all phases, aortic enhancement was significantly higher with protocol B (P = .046, P < .001, P < .001, and P = .002). Hepatic enhancement during four phases was 6, 21, 48, and 34 HU with protocol A. Corresponding values were 3, 17, 47, and 35 HU with protocol B. Hepatic enhancement was significantly higher with protocol A during first and second phases (P < .001 for both), although there was no significant difference between protocols during third and fourth phases (P = .778 and P = .178, respectively). Medians of tumor-to-liver contrast during four phases were 22, 34, 0.5, and -1.1 HU with protocol A. Corresponding values were 23, 45, 0, and -8.6 HU with protocol B. Tumor-to-liver contrast was significantly higher with protocol B during second phase (P = .049), although there was no difference between protocols during other phases., Conclusion: When total iodine dose was adjusted to body weight and injection duration was fixed, rapid administration of moderate concentration of contrast material was more effective for depiction of hypervascular HCC than was high concentration of contrast material., ((c) RSNA, 2004.)