Search

Purpose To evaluate the technical feasibility and therapeutic outcomes of percutaneous US/MRI fusion-guided radiofrequency ablation (RFA) of recurrent subcentimeter-sized hepatocellular carcinomas (HCCs). Materials and Methods For this retrospective study, between January 2012 and December 2014 a total of 194 planning US examinations were performed in 186 patients (159 men and 27 women; mean age, 61.1 years ± 10.0 [standard deviation]) for newly developed subcentimeter recurrent HCCs. These recurrent HCCs were defined as hypervascular nodules (>5.5 mm and <10 mm) with typical MRI findings of HCC. The study assessed how often US/MRI fusion-guided percutaneous RFA was deemed technically feasible at planning US examination (the feasibility rate) and the therapeutic outcomes after RFA, including the rates of technical success, technique efficacy, local tumor progression (LTP), and major complications. Cumulative LTP rates were estimated with the Kaplan-Meier method. Results The feasibility rate of percutaneous RFA at planning US examination was 65.7% (138 of 210 HCCs). The most common reason for RFA infeasibility was that an index tumor was inconspicuous at US. Among 138 subcentimeter HCCs feasible for RFA, 125 lesions underwent percutaneous RFA. The rates of both technical success and technique efficacy were 98.4% (123 of 125). The cumulative LTP rates at 1, 2, and 3 years were 3.6%, 5.4%, and 7.4%, respectively. The major complication rate was 2.5% (three of 119). Conclusion Percutaneous US/MRI fusion-guided radiofrequency ablation (RFA) was feasible in approximately two-thirds of subcentimeter recurrent hepatocellular carcinomas (HCCs). Percutaneous US/MRI fusion-guided RFA is a safe and effective treatment modality for patients with subcentimeter recurrent HCCs., (© RSNA, 2018 Online supplemental material is available for this article.)

Purpose To compare the long-term therapeutic outcomes of radiofrequency (RF) ablation for hepatocellular carcinoma (HCC) in subcapsular versus nonsubcapsular locations by using propensity score matching. Materials and Methods RF ablation for subcapsular HCC is controversial because of a high risk of incomplete ablation or major complications. This retrospective study was approved by the institutional review board, and the requirement for informed consent was waived. Between April 2006 and December 2011, 508 consecutive patients (396 men, 112 women; age range, 30-80 years) with a single HCC (Barcelona Clinic Liver Cancer stage 0 or A) underwent ultrasonography-guided percutaneous RF ablation as a first-line treatment. The patients were divided into two groups according to tumor location: subcapsular (n = 227) and nonsubcapsular (n = 281). Subcapsular HCC was defined as an index tumor located within 0.1 cm of the liver capsule. The association of subcapsular location and therapeutic outcomes of RF ablation was evaluated, including (a) local tumor progression (LTP) by using a competing risk regression model and (b) overall survival (OS) by using a Cox proportional hazards model according to propensity score matched data. The major complication rates from both overall data and matched data were assessed. Results Matching yielded 163 matched pairs of patients. In the two matched groups, cumulative LTP rates were 18.8% and 20.9% at 3 and 5 years, respectively, in the subcapsular group and 13.2% and 16.0% in the nonsubcapsular group. Corresponding OS rates were 90.7% for 3 years and 83.2% for 5 years in the subcapsular group and 91.4% and 79.1%, respectively, in the nonsubcapsular group. Hazard ratios (HRs) for LTP (HR = 1.37, P = .244) and OS (HR = 0.86, P = .604) were not significantly different between the two matched groups. Additionally, differences in major complication rates were not significant between groups for the two sets of data (P > .05). Conclusion The differences in LTP, OS, and major complication rates of RF ablation for HCC were not significant between subcapsular and nonsubcapsular groups. (©) RSNA, 2016.

Purpose: To evaluate the relationships between T2 signal intensity and semiquantitative perfusion magnetic resonance (MR) parameters of uterine fibroids in patients who were screened for MR-guided high-intensity focused ultrasound (HIFU) ablation., Materials and Methods: Institutional review board approval was granted, and informed consents were waived. One hundred seventy most symptom-relevant, nondegenerated uterine fibroids (mean diameter, 7.3 cm; range, 3.0-17.2 cm) in 170 women (mean age, 43.5 years; range, 24-56 years) undergoing screening MR examinations for MR-guided HIFU ablation from October 2009 to April 2014 were retrospectively analyzed. Fibroid signal intensity was assessed as the ratio of the fibroid T2 signal intensity to that of skeletal muscle. Parameters of semiquantitative perfusion MR imaging obtained during screening MR examination (peak enhancement, percentage of relative peak enhancement, time to peak [in seconds], wash-in rate [per seconds], and washout rate [per seconds]) were investigated to assess their relationships with T2 signal ratio by using multiple linear regression analysis. Correlations between T2 signal intensity and independently significant perfusion parameters were then evaluated according to fibroid type by using Spearman correlation test., Results: Multiple linear regression analysis revealed that relative peak enhancement showed an independently significant correlation with T2 signal ratio (Β = 0.004, P < .001). Submucosal intracavitary (n = 20, ρ = 0.275, P = .240) and type III (n = 18, ρ = 0.082, P = .748) fibroids failed to show significant correlations between perfusion and T2 signal intensity, while significant correlations were found for all other fibroid types (ρ = 0.411-0.629, P < .05)., Conclusion: In possible candidates for MR-guided HIFU ablation, the T2 signal intensity of nondegenerated uterine fibroids showed an independently significant positive correlation with relative peak enhancement in most cases, except those of submucosal intracavitary or type III fibroids.

Purpose: To evaluate the frequency, risk factors, and clinical significance of aggressive intrasegmental recurrence (AIR) found after radiofrequency (RF) ablation for hepatocellular carcinoma (HCC)., Materials and Methods: Institutional review board approval was obtained for this retrospective study. Between March 2005 and December 2010, 539 patients (414 men, 125 women; mean age, 57.91 years; age range, 30-82 years) underwent ultrasonography-guided percutaneous RF ablation as a first-line treatment for a single HCC classified as Barcelona Clinic Liver Cancer (BCLC) stage 0 or A. AIR of HCC was defined as (a) initial tumor recurrence with disease-free status at least 6 months after initial RF ablation and (b) the simultaneous development of multiple nodular (at least three) or infiltrative tumor recurrence in the treated segment. Patients were stratified into two groups: those with AIR (n = 20) and those without AIR (n = 519) during follow-up. Risk factors for AIR were assessed with logistic regression analysis, and risk factors for long-term overall survival were assessed with time-dependent Cox proportional hazard models., Results: In a median follow-up period of 49 months (range, 6-95 months), AIR was observed in 3.7% of the patients (20 of 539 patients), with the frequency increasing to 15% in the subgroup with periportal HCC (11 of 72 patients). AIRs manifested as either multiple nodular type (n = 14, BCLC stage A or B) or diffusely infiltrative type with tumor thrombus formation (n = 6, BCLC stage C). At multivariate analysis, periportal tumor location and younger patient age were significant risk factors for AIR. The presence of AIR during the follow-up period has a significant effect on the overall survival rate (hazard ratio = 5.72, P = .002)., Conclusion: The overall frequency of AIR after RF ablation for HCC was low, with periportal location and patient age showing a significant relationship to the development of AIR. The occurrence of AIR had an adverse effect on overall survival rate.

Purpose: To compare radiofrequency (RF) ablation with nonanatomic resection (NAR) as first-line treatment in patients with a single Barcelona Clinic Liver Cancer (BCLC) stage 0 or A hepatocellular carcinoma (HCC) and to evaluate the long-term outcomes of both therapies., Materials and Methods: This retrospective study was approved by the institutional review board. The requirement for informed consent was waived. Data were reviewed from 580 patients with HCCs measuring 3 cm or smaller (BCLC stage 0 or A) who underwent ultrasonographically (US) guided percutaneous RF ablation (n = 438) or NAR (n = 142) as a first-line treatment. Local tumor progression, intrahepatic distant recurrence, disease-free survival, and overall survival rates were analyzed by using propensity score matching to compare therapeutic efficacy. In addition, major complications and length of postoperative hospital stay were compared., Results: Before propensity score matching (n = 580), the 5-year cumulative rates of local tumor progression for RF ablation and NAR (20.9% vs 12.7%, respectively; P = .093) and overall survival rates (85.5% vs 90.9%, respectively; P = .194) were comparable, while the 5-year cumulative intrahepatic distant recurrence rates (62.7% vs 36.6%, respectively; P < .001) and disease-free survival rates (31.7% vs 61.1%, respectively; P < .001) in the NAR group were significantly better than those in the RF ablation group. After matching (n = 198), there were no significant differences in therapeutic outcomes between the RF ablation and NAR groups, including 5-year cumulative intrahepatic distant recurrence (47.0% vs 40.2%, respectively; P = .240) and disease-free survival rates (48.9% vs 54.4%, respectively; P = .201). RF ablation was superior to NAR for major complication rates and length of postoperative hospital stay (P < .001)., Conclusion: In patients with one BCLC stage 0 or A (≤ 3 cm) HCC who received RF ablation or NAR as first-line treatment, there were no significant differences in long-term therapeutic outcomes; however, RF ablation was associated with fewer major complications and a shorter hospital stay after treatment., (RSNA, 2015)

Purpose: To compare the long-term outcomes of repeated hepatic resection and radiofrequency (RF) ablation for recurrent hepatocellular carcinoma (HCC) by using propensity score matching., Materials and Methods: This retrospective study was approved by the institutional review board, and the requirement to obtain informed consent was waived. Thirty-nine patients who underwent repeated hepatic resection and 178 who underwent RF ablation for recurrent HCC (mean tumor size ± standard deviation, 1.8 cm ± 0.7) between November 1994 and December 2012 were included in the study. Patients ranged in age from 24 to 85 years (mean, 54.9 years). Men ranged in age from 25 to 85 years (mean, 54.8 years), and women ranged in age from 24 to 76 years (mean, 55.4 years). A 1:2 repeated hepatic resection group-RF ablation group matching was done by using propensity score matching. The overall survival (OS) and disease-free survival (DFS) were compared before and after propensity score matching. Complications were assessed., Results: Before matching, OS rates at 1, 3, 5, and 8 years were 88.8%, 88.8%, 83.9%, and 56.3%, respectively, with repeated hepatic resection and 98.9%, 82.5%, 71.0%, and 58.3% for RF ablation. DFS rates at 1, 3, and 5 years were 66.1%, 48.5%, and 43.1% for repeated hepatic resection and 70.1%, 40.8%, and 30.0% for RF ablation. After matching, the OS rates at 1, 3, 5, and 8 years were 98.7%, 85.7%, 72.1%, and 68.6%, respectively, and the DFS rates at 1, 3, and 5 years were 71.8%, 45.1%, and 39.4% in the RF ablation group (n = 78). Neither the OS nor DFS rate was significantly different between the two groups before matching (P = .686 and P = .461) and after matching (P = .834 and P = .960). The postoperative mortality rate was 2.6% in the repeated hepatic resection group and 0% in the RF ablation group., Conclusion: The long-term OS and DFS were not significantly different between repeated hepatic resection and RF ablation for patients with recurrent HCC after hepatic resection., ((©) RSNA, 2015.)

Purpose: To determine whether semiquantitative perfusion magnetic resonance (MR) imaging parameters are associated with therapeutic effectiveness of MR imaging-guided high-intensity focused ultrasound ( HIFU high-intensity focused ultrasound ) ablation of uterine fibroids and which semiquantitative perfusion parameters are significant with regard to treatment efficiency., Materials and Methods: This study was approved by the institutional review board, and informed consent was obtained from all subjects. Seventy-seven women (mean age, 43.3 years) with 119 fibroids (mean diameter, 7.5 cm) treated with MR imaging-guided HIFU high-intensity focused ultrasound ablation were analyzed. The correlation between semiquantitative perfusion MR parameters (peak enhancement, relative peak enhancement, time to peak, wash-in rate, washout rate) and heating and ablation efficiencies (lethal thermal dose volume based on MR thermometry and nonperfused volume based on immediate contrast-enhanced image divided by intended treatment volume) were evaluated by using a linear mixed model on a per-fibroid basis. The specific value of the significant parameter that had a substantial effect on treatment efficiency was determined., Results: The mean peak enhancement, relative peak enhancement, time to peak, wash-in rate, and washout rate of the fibroids were 1293.1 ± 472.8 (range, 570.2-2477.8), 171.4% ± 57.2 (range, 0.6%-370.2%), 137.2 seconds ± 119.8 (range, 20.0-300.0 seconds), 79.5 per second ± 48.2 (range, 12.5-236.7 per second), and 11.4 per second ± 10.1 (range, 0-39.3 per second), respectively. Relative peak enhancement was found to be independently significant for both heating and ablation efficiencies (B = -0.002, P < .001 and B = -0.003, P = .050, respectively). The washout rate was significantly associated with ablation efficiency (B = -0.018, P = .043). Both efficiencies showed the most abrupt transitions at 220% of relative peak enhancement., Conclusion: Relative peak enhancement at semiquantitative perfusion MR imaging was significantly associated with treatment efficiency of MR imaging-guided HIFU high-intensity focused ultrasound ablation of uterine fibroids, and a value of 220% or less is suggested as a screening guideline for more efficient treatment.

Purpose: To compare the long-term therapeutic outcomes of radiofrequency (RF) ablation for small perivascular hepatocellular carcinoma (HCC) and nonperivascular HCC., Materials and Methods: This retrospective study was approved by the institutional review board. Between December 2004 and April 2008, 241 patients (175 men and 66 women; age range, 32-82 years) with a single early-stage HCC that was 3 cm or smaller in the greatest dimension underwent ultrasonography-guided percutaneous RF ablation as a first-line treatment. The patients were divided into two groups according to the presence or absence of contacting hepatic vessels that were 3 mm or larger in axial diameter: a group with perivascular HCC (n = 58) and a group with nonperivascular HCC (n = 183). Cumulative local tumor progression, disease-free and long-term survival rates, and prognostic factors were assessed by using Cox proportional hazard models with Bonferroni correction., Results: The overall median follow-up period was 58 months (range, 13-92 months). The cumulative local tumor progression rates were 10%, 16%, and 26% at 1, 3, and 5 years, respectively, in the perivascular group, and 6.7%, 15.5%, and 20.5% in the nonperivascular group; the differences were not significant (P = .323). The corresponding disease-free survival rates were 79%, 41%, and 29% in the perivascular group and 71.3%, 38.7%, and 26.0% in the nonperivascular group, with no significant difference (P = .689). The corresponding overall survival rates were 100%, 94%, and 82% in the perivascular group and 100%, 88.4%, and 73.9% in the nonperivascular group, also without significant difference (P = .267). There was no significant prognostic factor for local tumor progression, whereas extrahepatic and intrahepatic distant recurrences were significant prognostic factors for overall survival in multivariable analysis., Conclusion: The long-term therapeutic outcomes of RF ablation as first-line treatment for small perivascular HCC were similar to those for nonperivascular HCC., (RSNA, 2013)

Purpose: To determine whether intraprocedural thermal parameters as measured with magnetic resonance (MR) thermometry can be used to predict immediate or delayed therapeutic response after MR-guided high-intensity focused ultrasound (HIFU) ablation of uterine fibroids., Materials and Methods: Institutional review board approval and subject informed consent were obtained. A total of 105 symptomatic uterine fibroids (mean diameter, 8.0 cm; mean volume, 251.8 mL) in 71 women (mean age, 43.3 years; age range, 25-52 years) who underwent volumetric MR HIFU ablation were analyzed. Correlations between tumor-averaged intraprocedural thermal parameters (peak temperature, thermal dose efficiency [estimated volume of 240 equivalent minutes at 43°C divided by volume of treatment cells], and temperature decay rate after sonication) and the immediate ablation efficiency (ratio of nonperfused volume [NPV] at immediate follow-up to treatment cell volume) or ablation sustainability (ratio of NPV at 3-month follow-up to NPV at immediate follow-up) were assessed with linear regression analysis., Results: A total of 2818 therapeutic sonications were analyzed. At immediate follow-up with MR imaging (n = 105), mean NPV-to-fibroid volume ratio and ablation efficiency were 0.68 ± 0.26 (standard deviation) and 1.35 ± 0.75, respectively. A greater thermal dose efficiency (B = 1.894, P < .001) and slower temperature decay rate (B = -1.589, P = .044) were independently significant factors that indicated better immediate ablation efficiency. At 3-month follow-up (n = 81), NPV had decreased to 43.1% ± 21.0 of the original volume, and only slower temperature decay rate was significantly associated with better ablation sustainability (B = -0.826, P = .041)., Conclusion: The postsonication temperature decay rate enables prediction of both immediate and delayed therapeutic responses, whereas thermal dose efficiency enables prediction of immediate therapeutic response to MR HIFU ablation of uterine fibroids., (© RSNA, 2013.)

Purpose: To evaluate the role of core-needle biopsy (CNB) in thyroid nodules with nondiagnostic results at previous fine-needle aspiration (FNA)., Materials and Methods: From October 2008 to July 2011, 155 nodules from 155 patients (37 men, 118 women) with a mean age of 51.8 years (age range, 22-76 years) with nondiagnostic results at previous FNA were reviewed retrospectively. The Bethesda system for reporting thyroid cytopathologic results was used to assign FNA and CNB findings. Malignant nodules (n = 37) were diagnosed after surgery. Benign nodules (n = 79) were diagnosed either after surgery, with benign findings after FNA and/or CNB that had been repeated at least twice, or after benign cytology findings at FNA or CNB with a stable size at follow-up. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of ultrasonographically guided CNB were evaluated., Results: At CNB, two nodules (1.3%) showed nondiagnostic results, and 135 nodules (87.1%) had conclusive diagnoses. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of core biopsies for the detection of malignancy were 94.6% (35 of 37), 100% (79 of 79), 100% (35 of 35), 97.5% (79 of 81), and 98.3% (114 of 116), respectively. For 28 nodules, nondiagnostic results were found after two or more FNA procedures; however, diagnostic surgery was performed in only one patient., Conclusion: CNB of the thyroid nodule demonstrates high rates of conclusive and accurate diagnoses in patients for whom previous FNA results were nondiagnostic, thereby reducing the need for unnecessary diagnostic surgery.

Purpose: To evaluate the accuracy of the size and location of the ablation zone produced by volumetric magnetic resonance (MR) imaging-guided high-intensity focused ultrasound ablation of uterine fibroids on the basis of MR thermometric analysis and to assess the effects of a feedback control technique., Materials and Methods: This prospective study was approved by the institutional review board, and written informed consent was obtained. Thirty-three women with 38 uterine fibroids were treated with an MR imaging-guided high-intensity focused ultrasound system capable of volumetric feedback ablation. Size (diameter times length) and location (three-dimensional displacements) of each ablation zone induced by 527 sonications (with [n=471] and without [n=56] feedback) were analyzed according to the thermal dose obtained with MR thermometry. Prospectively defined acceptance ranges of targeting accuracy were ±5 mm in left-right (LR) and craniocaudal (CC) directions and ±12 mm in anteroposterior (AP) direction. Effects of feedback control in 8- and 12-mm treatment cells were evaluated by using a mixed model with repeated observations within patients., Results: Overall mean sizes of ablation zones produced by 4-, 8-, 12-, and 16-mm treatment cells (with and without feedback) were 4.6 mm±1.4 (standard deviation)×4.4 mm±4.8 (n=13), 8.9 mm±1.9×20.2 mm±6.5 (n=248), 13.0 mm±1.2×29.1 mm±5.6 (n=234), and 18.1 mm±1.4×38.2 mm±7.6 (n=32), respectively. Targeting accuracy values (displacements in absolute values) were 0.9 mm±0.7, 1.2 mm±0.9, and 2.8 mm±2.2 in LR, CC, and AP directions, respectively. Of 527 sonications, 99.8% (526 of 527) were within acceptance ranges. Feedback control had no statistically significant effect on targeting accuracy or ablation zone size. However, variations in ablation zone size were smaller in the feedback control group., Conclusion: Sonication accuracy of volumetric MR imaging-guided high-intensity focused ultrasound ablation of uterine fibroids appears clinically acceptable and may be further improved by feedback control to produce more consistent ablation zones., (© RSNA, 2012)

Purpose: To evaluate initial clinical outcomes of volumetric magnetic resonance (MR)-guided high-intensity focused ultrasound (HIFU) ablation by using a one-layer strategy to treat large (>10 cm in diameter) uterine fibroids, with investigation of the correlation between effectiveness of the one-layer strategy and dynamic contrast material-enhanced (DCE) MR parameters., Materials and Methods: Institutional review board approval and informed consent were obtained. Twenty-seven women (mean age, 44.5 years) with 27 large uterine fibroids (mean diameter, 11.3 cm ± 1.4 [standard deviation] [range, 10.1-16.0 cm]; fibroid volume, 502.5 mL ± 214.3 [range, 253.8-1184.0 mL]) underwent volumetric MR-guided HIFU ablation with a one-layer strategy. (All treatment cells were placed in one coronal plane at a depth of half to anterior two-thirds of the anteroposterior dimension of fibroids.) Treatment time, immediate nonperfused volume (NPV), and effectiveness of a one-layer strategy (ratio of immediate NPV to total volume of treatment cells planned) correlating with baseline DCE MR parameters (volume transfer constant [K(trans)], fractional extravascular extracellular space, and fractional blood plasma volume [Pearson correlation test]), complications, 3-month follow-up volumes, and symptom severity score (SSS) changes (paired t test) were assessed retrospectively., Results: All treatments showed technical success in one session (mean treatment time, 166.2 minutes ± 38.9). NPV was 301.3 mL ± 119.1, which was 64.2% ± 19.9 (<50%, n = 4; ≥ 50%, n = 23) of fibroid volume. Ratio of immediate NPV to total volume of treatment cells (1.79 ± 0.61) negatively correlated with DCE MR imaging K(trans) values (r = -0.426, P = .017). Minor complications occurred in five patients (18.5% [thermal injury of abdominal wall, n = 3; 30-day leg numbness, n = 1; cystitis, n = 1]). At 3-month follow-up (n = 18), mean SSS had decreased from 37.4 at baseline to 24.0 (P < .001), and volume reduction ratio was 0.64 ± 0.15 (P < .001)., Conclusion: Volumetric MR-guided HIFU ablation with a one-layer strategy is safe and effective for treatment of large uterine fibroids. Effectiveness of this strategy showed a significant negative correlation with K(trans) values at baseline DCE MR imaging.

Purpose: To retrospectively assess the incremental value of an apparent diffusion coefficient (ADC) map combined with T2-weighted magnetic resonance (MR) images compared with T2-weighted images alone for prostate cancer detection by using a pathologic map as the reference standard., Materials and Methods: This retrospective study was approved by the institutional review board; informed consent was waived. The study included 52 patients (mean age, 65 years +/- 5 [standard deviation]; range, 48-76 years) who underwent endorectal MR imaging and step-section histologic examination. Three readers with varying experience levels reviewed T2-weighted images alone, the ADC map alone, and T2-weighted images and ADC maps. The prostate was divided into 12 segments. The probability of prostate cancer in each segment on MR images was recorded with a five-point scale. Areas under the receiver operating characteristic curve (AUCs) were compared by using the Z test; sensitivity and specificity were determined with the Z test after adjusting for data clustering., Results: AUC of T2-weighted and ADC data (reader 1, 0.90; reader 2, 0.88; reader 3, 0.76) was greater than that of T2-weighted images (reader 1, 0.79; reader 2, 0.75; reader 3, 0.66) for all readers (P < .0001 in all comparisons). AUC of T2-weighted and ADC data was greater for readers 1 and 2 than for reader 3 (P < .001). Sensitivity of T2-weighted and ADC data (reader 1, 88%; reader 2, 81%; and reader 3, 78%) was greater than that of T2-weighted images (reader 1, 74%; reader 2, 67%; reader 3, 67%) for all readers (P = .01 for reader 1; P = .02 for readers 2 and 3). Specificity of T2-weighted and ADC data was greater than that of T2-weighted images for reader 1 (88% vs 79%, P = .03) and reader 2 (89% vs 77%, P < .001)., Conclusion: The addition of an ADC map to T2-weighted images can improve the diagnostic performance of MR imaging in prostate cancer detection., ((c) RSNA, 2008.)

Purpose: To retrospectively evaluate the imaging features of early bile duct carcinoma and to compare these features with histopathologic findings., Materials and Methods: The institutional review board did not require its approval or informed patient consent for this study. Twenty-one patients (13 men, eight women; mean age, 60 years; range, 48-75 years) with early bile duct carcinoma that was surgically resected and histopathologically confirmed were included. Ultrasonography (US) was performed in 15 patients, computed tomography (CT) in 21, cholangiography in 18, and magnetic resonance (MR) cholangiography in six. Two radiologists retrospectively reviewed imaging features by consensus; they compared growth pattern of tumors, integrity of the bile duct wall that harbored the tumor, and periductal infiltration with histopathologic findings., Results: Pathologic specimens showed intraluminal tumor growth in all cases. Tumors were confined to the mucosa in 11 patients and involved the fibromuscular layer in 10 patients. In four of the 10 intrahepatic cholangiocarcinomas, four of the five hilar cholangiocarcinomas, and six of the six extrahepatic cholangiocarcinomas, there were intraductal tumor masses and the wall of the tumor-bearing bile ducts was preserved without periductal infiltration on US and CT images. On cholangiograms and MR cholangiograms, tumors were better delineated but the wall invasion could not be evaluated. No difference in image findings was found between carcinoma confined to the mucosa and carcinoma involving the fibromuscular layer., Conclusion: Imaging features of early bile duct carcinoma are a tumor mass in the bile duct lumen and integrity of the tumor-bearing bile duct wall without infiltration outside the wall., ((c) RSNA, 2005)

Purpose: To retrospectively evaluate the correlation between the degree of contrast enhancement on dynamic computed tomographic (CT) scans and the degree of neoangiogenesis and sinusoidal capillarization in hepatocellular carcinoma (HCC)., Materials and Methods: The institutional review board did not require approval or informed patient's consent for the review of medical records or images. Dynamic CT scans of 97 nodular HCCs in 97 patients (79 men, 18 women; age range, 29-73 years; mean age, 54 years) were evaluated in terms of the attenuation change in the arterial, portal venous, and delayed phases, and the results were correlated with the number of unpaired arteries and the degree of sinusoidal capillarization at histopathologic examination. The mean attenuation value of the nodular HCCs on triple-phase helical CT scans was correlated with the number of unpaired arteries and the degree of sinusoidal capillarization. Statistical analysis was performed with the Spearman rank correlation test., Results: The number of unpaired arteries in the nodular HCCs was found to correlate with the degree of contrast enhancement in the arterial phase (r = 0.225, P = .027), but did not correlate with the degree of contrast enhancement in the portal and delayed phases. The degree of sinusoidal capillarization did not correlate linearly with the mean attenuation of the nodular HCCs in any phase of contrast enhancement., Conclusion: The degree of contrast enhancement of the nodular HCCs in the arterial phase tended to correlate with the number of unpaired arteries, but no correlation was evident between the degree of contrast enhancement and sinusoidal capillarization in any phase of CT imaging.

Purpose: To determine whether transrectal ultrasonography (US) with intrarectal water instillation can improve the depiction and accuracy of US in local staging of rectal tumors., Materials and Methods: Between October 1999 and February 2002, 63 patients (mean age, 56 years; age range, 23-91 years) with 63 rectal tumors were evaluated with transrectal US before and after intrarectal water instillation. Transrectal US examinations were performed with a 7-10-MHz radial transducer. Immediately after the first transrectal US examination, the rectal lumen was filled with 50-150 mL of degassed water, and a second US examination was performed. All patients underwent surgery within 1 month after transrectal US. Depiction of the tumor was compared between the two methods. The McNemar test was used to compare the accuracy between the two techniques in local staging of the tumor by using pathologic findings in the resected specimen as the standard., Results: The tumors ranged from 0.5 to 8.0 cm (mean, 2.8 cm) as measured at pathologic evaluation. All 63 tumors were clearly depicted at transrectal US after water instillation, while only 42 (67%) of the tumors were depicted at transrectal US before water instillation. In the 42 tumors clearly depicted at transrectal US examinations both before and after water instillation, the accuracy of transrectal US in local tumor staging was significantly higher after water instillation (85.7% [36 of 42]) than before water instillation (57.1% [24 of 42]; P <.001)., Conclusion: Water instillation during transrectal US examination of rectal tumors improves the depiction and local staging of the tumors., (Copyright RSNA, 2004)

Purpose: To evaluate the therapeutic efficacy and safety of percutaneous radiofrequency (RF) ablation for recurrent hepatocellular carcinoma (HCC) in the liver after hepatectomy., Materials and Methods: Forty-five patients with 53 recurrent HCC tumors in the liver underwent percutaneous RF ablation with ultrasonographic guidance. All patients had a history of hepatic resection for HCC. The mean diameter of recurrent tumors was 2.1 cm (range, 0.8-4.0 cm). All patients were followed up for at least 10 months after ablation (range, 10-40 months; mean, 23 months). Therapeutic efficacy and complications were evaluated with multiphase helical computed tomography (CT) at regular follow-up visits. Overall and disease-free survival rates were calculated., Results: At follow-up CT after initial RF ablation, 11 (21%) of 53 ablated HCC tumor sites showed residual tumor or local tumor progression. After additional RF ablation, complete ablation of 46 (87%) of 53 tumors was attained. Also at initial follow-up CT, before either additional RF ablation or other treatment was performed, 21 (47%) of 45 patients were found to have 41 new HCC tumors at other liver sites. Of these, nine tumors in eight patients were treatable with a second application of RF ablation. Overall survival rates at 1, 2, and 3 years were 82%, 72%, and 54%, respectively. No deaths or complications requiring further treatment occurred as a result of RF ablation., Conclusion: Percutaneous RF ablation is an effective and safe method for treating recurrent HCC in the liver after hepatectomy, with a good overall patient survival rate., (Copyright RSNA, 2004)

Purpose: To compare ferumoxides-enhanced magnetic resonance (MR) imaging with triple-phase helical computed tomography (CT) for the preoperative depiction of hepatocellular carcinoma (HCC)., Materials and Methods: Seventy consecutive patients with a total of 79 HCC nodules underwent ferumoxides-enhanced MR imaging and triple-phase helical CT before surgery. The diagnosis of HCC was established by means of pathologic examination after surgical resection in all patients. MR images obtained with all sequences and triple-phase helical CT images were reviewed independently by three radiologists on a segment-by-segment basis. Accuracy for diagnosis of HCC was assessed by applying receiver operating characteristic (ROC) analysis to observations of 78 hepatic segments with at least one HCC nodule and 70 segments without HCC., Results: The diagnostic accuracy of findings at ferumoxides-enhanced MR imaging (with mean area-under-the-ROC-curve [A(z)] values for the three observers of 0.986, 0.979, and 0.980) was significantly higher (P <.001) than that of findings at triple-phase helical CT (with mean A(z) values for the three observers of 0.945, 0.948, and 0.964). The mean sensitivity of MR imaging (95%, 222 of 234 segments) was also significantly higher than that of triple-phase helical CT (88%, 205 of 234 segments) (P =.001, McNemar test). The mean specificity was 97% (261 of 270 segments) for MR imaging and 98% (264 of 270 segments) for CT, but this difference was not significant (P =.754, McNemar test)., Conclusion: Ferumoxides-enhanced MR imaging is superior to triple-phase helical CT for the preoperative depiction of HCC., (Copyright RSNA, 2003)

Purpose: To determine serial changes in hepatocellular carcinomas (HCCs) treated with percutaneous radio-frequency (RF) ablation at long-term follow-up multiphase helical computed tomography (CT)., Materials and Methods: There were 43 nodular HCCs in 40 patients at follow-up CT performed not less than 12 months after RF ablation. All patients underwent follow-up multiphase helical CT immediately, 1 month, and then every 3 months after percutaneous RF ablation. The serial changes in attenuation, enhancement pattern, shape, other findings, and volume of the ablated lesions were analyzed at follow-up CT., Results: Thirty-eight (88%) of 43 ablated lesions were of low attenuation, with absence of contrast material enhancement at immediate and 1-month follow-up CT, which is suggestive of successful treatment. The remaining five lesions (12%) showed peripheral nodular enhancement, suggesting residual viable tumor. Compared with volume changes at immediate follow-up CT, the mean percentages of volume change at 1, 4, 10, 16, and 19 months were 79%, 50%, 27%, 11%, and 6%, respectively. Of 43 ablated lesions, 24 (56%) were mostly round at immediate CT and remained unchanged at subsequent follow-up CT. Peripheral rim enhancement was seen in 34 (79%) of 43 lesions at immediate CT but resolved in all 34 lesions at 1-month follow-up CT. Other associated findings included iatrogenic arteriovenous shunt in 10 patients, perihepatic hemorrhage in three, and pneumothorax in one., Conclusion: Follow-up multiphase helical CT of HCCs treated with percutaneous RF ablation showed variable findings in the treated lesions and surrounding liver parenchyma.

Purpose: To correlate the conspicuity of hepatocellular carcinomas and dysplastic nodules on ferumoxides-enhanced magnetic resonance (MR) images with the number of Kupffer cells in the hepatic lesions, as compared with that in background liver in histopathologic findings., Materials and Methods: Sixty-nine histopathologically proved moderately or poorly differentiated hepatocellular carcinomas, 10 well-differentiated hepatocellular carcinomas, and 19 dysplastic nodules were retrospectively studied in 68 patients with cirrhosis who underwent ferumoxides-enhanced MR imaging. The contrast-to-noise ratio between the nodules and surrounding parenchyma was calculated at T2-weighted fast spin-echo imaging, and the difference in the number of Kupffer cells between the nodules and surrounding hepatic tissue was calculated histopathologically. The results of MR imaging and histopathologic examination were correlated., Results: All 69 moderately or poorly differentiated hepatocellular carcinomas had high contrast-to-noise ratios at MR imaging and large differences in the number of Kupffer cells. Six of the 10 well-differentiated hepatocellular carcinomas had contrast-to-noise ratios of zero or nearly zero, and five of these had little difference in the number of Kupffer cells. All 19 dysplastic nodules had contrast-to-noise ratios of zero or nearly zero, and there were virtually no differences in the number of Kupffer cells., Conclusion: Hepatocellular nodule conspicuity at ferumoxides-enhanced MR imaging depends on differences in the number of Kupffer cells within a nodule and the surrounding cirrhotic liver; moderately or poorly differentiated hepatocellular carcinomas can be distinguished from well-differentiated hepatocellular carcinomas and dysplastic nodules.

Purpose: To evaluate the usefulness of power Doppler ultrasonography (US) with a microbubble contrast agent in assessing the therapeutic response of hepatocellular carcinomas (HCCs) treated with percutaneous radio-frequency (RF) ablation., Materials and Methods: Forty patients with 45 nodular HCC lesions 1.0-3.8 cm in diameter underwent power Doppler US before and after intravenous injection of a microbubble contrast agent. The same procedures were repeated after US-guided percutaneous RF ablation. The results of these studies were compared with those of three-phase helical computed tomography (CT) performed immediately after RF ablation., Results: Before RF ablation, nonenhanced power Doppler US demonstrated flow signals within tumor in 33 of 45 HCCs. After contrast agent administration, flow signals increased or newly appeared in all cases. After RF ablation, none of the ablated tumors showed intratumoral flow signals at nonenhanced power Doppler US, whereas six showed marginal intratumoral flow signals at contrast agent-enhanced power Doppler US. These six tumors were found to have small enhancing foci, suggestive of viable tumor, in corresponding areas at immediate follow-up CT. Additional RF ablation or transcatheter arterial chemoembolization was performed in these tumors., Conclusion: The results of power Doppler US with a microbubble contrast agent in HCCs treated with RF ablation correlated well with those of contrast-enhanced CT. Preliminary data suggest that contrast-enhanced power Doppler US can be a promising noninvasive technique for assessing therapeutic response.

Purpose: To determine the importance of the finding of segmental wall thickening in the colonic loop distal to colonic carcinoma at computed tomography (CT) by means of histopathologic correlation., Materials and Methods: Thirteen consecutive patients whose helical CT scans showed segmental wall thickening (>1 cm in maximal width, >5 cm in length) in the colonic loop distal to colonic carcinoma were included. The thickness and length of an involved segment, location, morphologic tumor type, CT patterns of wall thickening, and pericolic changes were evaluated. Surgical pathologic findings in all 13 patients were correlated with CT findings., Results: The involved segment distal to the colonic carcinoma showed circumferential wall thickening with a preserved wall layer pattern at CT. Pericolic changes of varying degrees were seen in 10 patients. Histopathologic examination revealed submucosal and subserosal edema (n = 6), chronic inflammation and fibrosis (n = 5), or both (n = 1), and no histopathologic alteration (n = 1). The tumors were mostly fungating (n = 11), larger than 5 cm in the greatest dimension (n = 12), located in the ascending colon (n = 10), and extended to pericolic adipose tissue (n = 11)., Conclusion: Colonic carcinoma, especially a large fungating type involving the ascending colon with pericolic infiltration, can produce segmental wall thickening in the distal segment at CT, which represents edema or colitis at histopathologic examination.

Purpose: To describe upper gastrointestinal (Gl) examination findings of low-grade gastric mucosa-associated lymphoid tissue (MALT) lymphoma and to correlate them with pathologic examination findings., Materials and Methods: A retrospective review of upper Gl examinations was performed in 25 patients with proved low-grade gastric MALT lymphomas. Upper Gl examinations were reviewed for common findings and most probable diagnosis, and these findings were correlated with pathologic findings in resected specimens in 15 patients., Results: The common findings at upper Gl examination included mucosal nodularity (n = 13), ulcer (n = 12), rugal thickening (n = 6), mass (n = 4), and enlarged areae gastricae (n = 2). The most probable diagnoses were early gastric carcinoma (n = 7), advanced gastric carcinoma (n = 6), gastritis (n = 9), and lymphoma (n = 3). Of 17 lesions found on resected specimens, six ulcers and two masses were not depicted at barium study. Disorganized convergent rugae projecting to multiple points and vague ulcer margins were present in four and seven lesions, respectively. Multiple ulcers were seen in two patients., Conclusion: Although the common radiographic and pathologic findings observed in low-grade gastric MALT lymphomas were similar to those of gastric carcinomas or gastritis, disorganized convergent rugae, vague ulcer margins, and multiplicity of lesions may be helpful in differentiating them from gastric carcinomas or gastritis.

Purpose: To determine the diagnostic accuracy of Doppler ultrasonography (US) in the detection of high-grade stenosis or occlusion of the celiac artery (CA) and superior mesenteric artery (SMA) and validate the previously reported Doppler US criteria., Materials and Methods: During a recent 36-month period, 82 patients were prospectively examined with Doppler US of the splanchnic arteries and with lateral abdominal aortography, regardless of their abdominal symptoms. The previously reported diagnostic criteria with the fasting peak systolic velocity measurement were prospectively used in all patients. The results of Doppler US were compared with those of lateral aortography., Results: The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of Doppler US for the detection of 70% or greater CA stenosis or occlusion were 100%, 87%, 57%, 100%, and 89%, respectively; for 70% or greater SMA stenosis or occlusion, these values were 100%, 98%, 93%, 100%, and 99%, respectively., Conclusion: Owing to its high accuracy in the diagnosis of high-grade splanchnic arterial stenosis or occlusion, Doppler US can be used as a screening method to help detect CA or SMA stenosis or occlusion and can reduce the use of unnecessary, invasive angiography.

The authors treated 21 patients with inoperable upper gastrointestinal tract malignant obstruction from the esophagus to the duodenum by means of intubation with a flexible covered stent with fluoroscopic guidance. Stent placement was successful and relief of dysphagia was immediate in 18 (86%) patients, without serious complication. The average dysphagia score decreased from 2.6 (dysphagia to liquids) to 1.0 (dysphagia to normal solid food). Placement of a flexible covered stent provides easy, safe, and effective palliation of upper gastrointestinal malignant obstruction.

Purpose: To determine the appearance of regenerative nodules in patients with liver cirrhosis at computed tomography (CT) during arterial portography (CTAP) and CT hepatic arteriography (CTHA)., Materials and Methods: CTAP and CTHA of the liver were performed in 28 consecutive patients with hepatocellular carcinoma (HCC) who were scheduled to undergo partial resection of the liver. Helical CTAP was performed after contrast material injection into the superior mesenteric artery followed by helical CTHA after contrast material injection into the hepatic artery. CT scans were analyzed for the presence of identifiable nodules and their size; results were correlated with gross and microscopic findings., Results: Resected livers showed cirrhosis in 20 patients, chronic hepatitis in four, and normal liver in four. Among the 20 patients with cirrhosis, regenerative nodules were demonstrated as enhancing 3-10 mm nodules surrounded by lower attenuation fibrous septa 0.8-1.5 mm thick at CTAP in seven patients and nonenhancing nodules of the same size surrounded by enhancing fibrous septa at CTHA in 15 patients. The degree of fibrosis determined the conspicuity of nodules., Conclusion: Regenerative nodules in cirrhotic liver are visualized as enhancing nodules surrounded by lower attenuation thin septa at CTAP and nonenhancing nodules surrounded by enhancing fibrous septa at CTHA. CTHA is more sensitive than CTAP in depicting regenerative nodules (P < .005).

Purpose: To assess whether color Doppler ultrasonography (US) can help diagnose early acute appendicitis in appendices of equivocal size at gray-scale US., Materials and Methods: In a retrospective study, color Doppler US findings were evaluated in 20 individuals with proved normal appendix at barium enema examination and in 50 patients in whom pathologic findings confirmed acute appendicitis. In a prospective study, the diagnostic value of hyperemia in the wall of the appendix in differentiating a normal from an inflamed appendix was evaluated in 26 patients with appendices of equivocal size (5-7 mm in maximal outer diameter) at grayscale US., Results: In the retrospective study, 44 of the 50 patients had hyperemia at color Doppler US. The remaining six patients had no hyperemia, and pathologic findings confirmed gangrenous appendices. The 20 patients with proved normal appendix at barium enema examination had no detectable blood flow in the wall. In the prospective study, 10 of 26 patients had hyperemia at color Doppler US, and pathologic findings confirmed early acute appendicitis. Results of barium enema examination (n = 12) or clinical follow-up (n = 4) confirmed no appendicitis in the remaining 16 patients., Conclusion: Hyperemia in the wall of the appendix at color Doppler US is a sensitive indicator for inflammation. A simple additional color Doppler US examination may be helpful in the diagnosis of early acute appendicitis when an appendix is well depicted and is equivocal in size at gray-scale US.

Purpose: To evaluate the diagnostic value of graded-compression ultrasonography (US) for the diagnosis of focal appendicitis confined to the tip., Materials and Methods: During a 4-year period, US was performed in 1,450 patients with clinically suspected acute appendicitis. Of these patients, 443 had appendicitis at pathologic examination, 20 of whom had focal appendicitis confined to the tip. Focal appendicitis confined to the tip was defined as occurring when the resected specimen had inflammation only at the distal third of the appendix., Results: Of 20 patients with focal appendicitis confirmed at pathologic examination, 17 patients (85%) had focal appendicitis that was correctly diagnosed at US. The remaining three patients' appendices were diagnosed at US as normal (false-negative cases). Five patients had perforation at the tip, and one patient had an appendicolith., Conclusion: Although US appears to be fairly accurate in the diagnosis of focal appendicitis confined to the tip, the entire length of the appendix should be evaluated in order to avoid a false-negative diagnosis.

Purpose: To assess the diagnostic usefulness of ultrasonography (US) in intussusception in children and determine whether color Doppler sonography (CDS) can indicate bowel viability and help in prediction of reducibility., Materials and Methods: US was used to examine 176 children in whom the presence of intussusception was clinically suspected. CDS was performed in 64 patients with 65 cases of intussusception proved with US., Results: The positive US findings were confirmed with air enema; the negative findings, with air enema in 46 patients and clinical follow-up in 66 patients (100% specificity and sensitivity). CDS indicated blood flow in 62 of 65 cases of intussusception; pneumatic reduction was achieved in 58 (94%) of these 62 cases. Four patients (6%) underwent manual reduction of viable bowel; three patients (5%) who had no color Doppler signal underwent segmental resection. The difference in reduction rates based on blood flow was statistically significant (P = .0008)., Conclusion: US is sensitive and specific in the diagnosis of intussusception, and CDS is a promising predictor of bowel viability.