Comparative study of standard and small transrectal transducers for prostate ultrasonography

PURPOSE

The objective of this study was to evaluate pain and image quality associated with the use of two different ultrasound transducers.

METHODS

Fifty healthy male participants aged 30 years or older were prospectively enrolled. All ultrasound procedures were performed using a V8 machine (Samsung Medison, Seoul, Korea) equipped with EA2-11 (conventional) and miniER7 (small-caliber) transrectal transducers, operated by a single genitourinary radiologist. To minimize bias, one group of volunteers underwent ultrasonography with the conventional transducer first, followed by the small transducer. For the remaining participants, the examinations were performed in the opposite order. Ultrasonography, including the measurement of total prostate and transitional zone volumes, was conducted in accordance with standard practice. After testing with both probes, participants were asked to rate their pain on a 10-point numerical rating scale (NRS). A radiologist then evaluated the quality of the images acquired with each probe using a 5-point numeric scale and compared the prostate volume measurements obtained by each method.

RESULTS

The mean NRS scores associated with the conventional and small transducers were 4.7±1.8 and 2.7±1.2, respectively (P<0.05). The mean ultrasound image qualities from the two transducers were statistically similar (4.78 and 4.74, P>0.05). The whole prostate gland volume as measured with the conventional transducer (mean±standard deviation, 24.2±9.1 mL) was greater than the measurement (22.1±8.7 mL) obtained with the small-caliber transducer (P<0.05). However, only two of the 50 whole gland volume measurements differed by more than two standard deviations.

CONCLUSION

The use of a small transrectal probe significantly reduced pain without compromising image quality.

Renal Doppler ultrasonography for predicting non-diabetic kidney disease in patients with diabetes

PURPOSE

This study was conducted to assess the role of renal Doppler ultrasonography (US) in predicting non-diabetic kidney disease (NDKD) in patients with diabetes, using histologic findings as the reference standard.

METHODS

Fifty-nine consecutive patients with diabetes who underwent renal Doppler US and native kidney biopsy were included in this retrospective, single-institutional study. Based on histologic findings, patients were classified as having diabetic nephropathy (DN) or NDKD. Renal Doppler US findings, including cortical echogenicity, corticomedullary differentiation, and the resistive index (RI), were compared between DN and NDKD. A subgroup analysis according to chronic kidney disease (CKD) status was also performed.

RESULTS

Cortical echogenicity and corticomedullary differentiation showed no significant differences between DN and NDKD (P=0.887 and P>0.99, respectively), whereas the RI was significantly higher in patients with DN than in those with NDKD (P=0.032). The subgroup analysis revealed a significant difference in the RI between DN and NDKD in patients with diabetes and CKD (P=0.010), but a significant difference was not found in those without CKD (P=0.713). When limited to patients with diabetes and CKD, the RI had an area under the curve value of 0.759, sensitivity of 57.1%, specificity of 81.0%, positive likelihood ratio of 3.0, and negative LR of 0.5 for predicting NDKD, using a cutoff value of ≤0.69.

CONCLUSION

Renal Doppler US may be useful in predicting NDKD in patients with diabetes and CKD.

Motion-Corrected versus Conventional Diffusion-Weighted Magnetic Resonance Imaging of the Liver Using Non-Rigid Registration

It is challenging to overcome motion artifacts in diffusion-weighted imaging (DWI) of the abdomen. This study aimed to evaluate the image quality of motion-corrected DWI of the liver using non-rigid registration in comparison with conventional DWI (c-DWI) in patients with liver diseases. Eighty-nine patients who underwent 3-T magnetic resonance imaging (MRI) of the liver were retrospectively included. DWI was performed using c-DWI and non-rigid motion-corrected (moco) DWI was performed in addition to c-DWI. The image quality and conspicuity of hepatic focal lesions were scored using a five-point scale by two radiologists and compared between the two DWI image sets. The apparent diffusion coefficient (ADC) was measured in three regions of the liver parenchyma and in hepatic focal lesions, and compared between the two DWI image sets. Moco-DWI achieved higher scores in image quality compared to c-DWI in terms of liver edge sharpness and hepatic vessel margin delineation. The conspicuity scores of hepatic focal lesions were higher in moco-DWI. The standard deviation values of ADC of the liver parenchyma were lower in the moco-DWI than in the c-DWI. Moco-DWI using non-rigid registration showed improved overall image quality and provided more reliable ADC measurement, with an equivalent scan time, compared with c-DWI.

Computed Tomography Indicators for Differentiating Stage 1 Borderline Ovarian Tumors from Stage I Malignant Epithelial Ovarian Tumors

Preoperative diagnosis of borderline ovarian tumors (BOTs) is of increasing concern. This study aimed to determine computed tomography (CT) features in differentiating stage 1 BOTs from stage I malignant epithelial ovarian tumors (MEOTs). A total of 170 ovarian masses (97 BOTs and 73 MEOTs) from 141 consecutive patients who underwent preoperative CT imaging were retrospectively analyzed. Two readers independently and retrospectively reviewed quantitative and qualitative CT features. Multivariate logistic analysis demonstrated that a larger tumor size (p = 0.0284 for reader 1, p = 0.0391 for reader 2) and a smaller solid component (p = 0.0007 for reader 1, p = 0.0003 for reader 2) were significantly associated with BOTs compared with MEOTs. In the subanalysis of cases with a solid component, smaller (p = 0.0092 for reader 1, p = 0.0014 for reader 2) and ill-defined (p = 0.0016 for reader 1, p = 0.0414 for reader 2) solid component was significantly associated with BOTs compared with MEOTs. Tumor size and the size and margin of the solid component were useful for differentiating stage 1 BOTs from stage 1 MEOTs on CT images.

Quantitative magnetic resonance imaging of chronic kidney disease: an experimental in vivo study using rat chronic kidney disease models

BACKGROUND

Recent advances in magnetic resonance imaging (MRI) may allow it to be an alternative emerging tool for the non-invasive evaluation of renal parenchymal disease.

PURPOSE

To validate the usefulness of quantitative multiparametric MRI protocols and suggest the suitable quantitative MR sequence protocol to evaluate parenchymal fibrosis using an animal model of chronic kidney disease (CKD) by long-term adenine intake.

MATERIAL AND METHODS

In this prospective animal study, 16 male Wistar rats were analyzed and categorized into three groups. Rats in the CKD groups underwent 0.25% adenine administration for three or six weeks. Quantitative MRI protocols, including diffusion-weighted imaging (DWI), T1ρ (T1 rho), and T2* mapping were performed using a 9.4-T animal MR scanner. A semi-quantitative histopathologic analysis for renal fibrosis was conducted. Quantitative MR values measured from anatomic regions of kidneys underwent intergroup comparative analyses.

RESULTS

The apparent diffusion coefficient (ADC) and T1 (T1 rho) values were significantly increased in all CKD groups. Values measured from the cortex and outer medulla showed significant intergroup differences. Total ADC values tended to increase according to periods, and T1ρ values increased in three weeks and decreased in six weeks.

CONCLUSION

Quantitative MRI protocols could be a non-invasive assessment modality in the diagnosis and evaluation of CKD. Particularly, T1ρ may be a suitable MR sequence to quantitatively assess renal parenchymal fibrosis.

Guidelines for Transrectal Ultrasonography-Guided Prostate Biopsy: Korean Society of Urogenital Radiology Consensus Statement for Patient Preparation, Standard Technique, and Biopsy-Related Pain Management

The Korean Society of Urogenital Radiology (KSUR) aimed to present a consensus statement for patient preparation, standard technique, and pain management in relation to transrectal ultrasound-guided prostate biopsy (TRUS-Bx) to reduce the variability in TRUS-Bx methodologies and suggest a nationwide guideline. The KSUR guideline development subcommittee constructed questionnaires assessing prebiopsy anticoagulation, the cleansing enema, antimicrobial prophylaxis, local anesthesia methods such as periprostatic neurovascular bundle block (PNB) or intrarectal lidocaine gel application (IRLA), opioid usage, and the number of biopsy cores and length and diameter of the biopsy needle. The survey was conducted using an Internet-based platform, and responses were solicited from the 90 members registered on the KSUR mailing list as of 2018. A comprehensive search of relevant literature from Medline database was conducted. The strength of each recommendation was graded on the basis of the level of evidence. Among the 90 registered members, 29 doctors (32.2%) responded to this online survey. Most KSUR members stopped anticoagulants (100%) and antiplatelets (76%) one week before the procedure. All respondents performed a cleansing enema before TRUS-Bx. Approximately 86% of respondents administered prophylactic antibiotics before TRUS-Bx. The most frequently used antibiotics were third-generation cephalosporins. PNB was the most widely used pain control method, followed by a combination of PNB plus IRLA. Opioids were rarely used (6.8%), and they were used only as an adjunctive pain management approach during TRUS-Bx. The KSUR members mainly chose the 12-core biopsy method (89.7%) and 18G 16-mm or 22-mm (96.5%) needles. The KSUR recommends the 12-core biopsy scheme with PNB with or without IRLA as the standard protocol for TRUS-Bx. Anticoagulants and antiplatelet agents should be discontinued at least 5 days prior to the procedure, and antibiotic prophylaxis is highly recommended to prevent infectious complications. Glycerin cleansing enemas and administration of opioid analogues before the procedure could be helpful in some situations. The choice of biopsy needle is dependent on the practitioners' situation and preferences.

Benign gallbladder diseases: Imaging techniques and tips for differentiating with malignant gallbladder diseases

Benign gallbladder diseases usually present with intraluminal lesions and localized or diffuse wall thickening. Intraluminal lesions of the gallbladder include gallstones, cholesterol polyps, adenomas, or sludge and polypoid type of gallbladder cancer must subsequently be excluded. Polyp size, stalk width, and enhancement intensity on contrast-enhanced ultrasound and degree of diffusion restriction may help differentiate cholesterol polyps and adenomas from gallbladder cancer. Localized gallbladder wall thickening is largely due to segmental or focal gallbladder adenomyomatosis, although infiltrative cancer may present similarly. Identification of Rokitansky-Aschoff sinuses is pivotal in diagnosing adenomyomatosis. The layered pattern, degree of enhancement, and integrity of the wall are imaging clues that help discriminate innocuous thickening from gallbladder cancer. High-resolution ultrasound is especially useful for analyzing the layering of gallbladder wall. A diffusely thickened wall is frequently seen in inflammatory processes of the gallbladder. Nevertheless, it is important to check for coexistent cancer in instances of acute cholecystitis. Ultrasound used alone is limited in evaluating complicated cholecystitis and often requires complementary computed tomography. In chronic cholecystitis, preservation of a two-layered wall and weak wall enhancement are diagnostic clues for excluding malignancy. Magnetic resonance imaging in conjunction with diffusion-weighted imaging helps to differentiate xathogranulomatous cholecystitis from gallbladder cancer by identifying the presence of fat and degree of diffusion restriction. Such distinctions require a familiarity with typical imaging features of various gallbladder diseases and an understanding of the roles that assorted imaging modalities play in gallbladder evaluations.

Whirlpool sign of adnexal torsion on CT: where can we find it?

Background

Whirlpool sign on computed tomography (CT) is pathognomic of adnexal torsion.

Purpose

To evaluate the visibility and common location of the whirlpool sign in adnexal torsion on CT.

Material and Methods

This retrospective study included 143 consecutive patients who underwent preoperative CT imaging and subsequent surgically confirmed as adnexal torsion. Two readers independently recorded the presence and location of whirlpool sign in adnexal torsion on CT. Patients with and without whirlpool sign were compared with regard to the size of the adnexal mass and the degree of torsion.

Results

Whirlpool sign was detected in 60 (42.0%) patients on the transverse CT plane and 79 (55.2%) patients on the coronal CT plane of 143 patients. The sign was significantly better detected on the coronal CT plane than on the transverse CT plane ( P = 0.03). The most common location of the sign included the posterolateral aspect of the adnexal mass on the transverse CT plane (25/60, 41.7%, P = 0.04) and the upper-lateral aspect of the adnexal mass on the coronal CT plane (45/79, 60.0%, P < 0.001). The size of the adnexal mass with whirlpool sign was significantly larger than the mass without whirlpool sign on the transverse CT plane (median 9.6 vs. 8.6 cm, P = 0.03). No significant difference in the degree of torsion was found between patients with and without whirlpool sign on CT ( P = 0.56–0.62).

Conclusion

Whirlpool sign of adnexal torsion is well detected at the upper-lateral aspect of adnexal mass on the coronal CT plane.

Korean ureter length: A computed tomography-based study

Purpose

We measured ureter length in healthy Koreans using reformatted computed tomography (UL_CT) and found ways to indirectly estimate ureter length by measuring LL_CT, the length between the ureteropelvic junction and the ureterovesical junction, and standing and sitting height.

Materials and Methods

A total of 508 ureters of 254 healthy patients (median age, 55.0 years; 148 males and 106 females) were included in this retrospective study. UL_CT, LL_CT, and sitting and standing body height were measured.

Results

The mean left and right UL_CT were 25.2±2.2 and 25.0±2.2 cm, respectively. The mean left and right LL_CT were 21.1±1.8 and 20.3±1.9 cm, respectively. Standing and sitting body height were 164.1±8.9 and 88.3±4.3 cm, respectively. Height was significantly correlated with UL_CT, but this relation was not linear (r²=0.064 standing height, 0.062 sitting height). However, LL_CT showed a significant linear correlation with UL_CT (r²=0.485). UL_CT can be estimated indirectly by the following equation: UL_CT=0.823×LL_CT+8.093.

Conclusions

We could measure the ureteral length of healthy Koreans by UL_CT. UL_CT could be estimated indirectly by LL_CT and standing and sitting height. Of these variables, LL_CT provided the most accurate estimate of ureteral length.

Prediction of Necrotizing Pancreatitis on Early CT Based on the Revised Atlanta Classification

Purpose

To investigate the clinical and CT features at admission to predict the progression to necrotizing pancreatitis (NP) in patients initially diagnosed with interstitial edematous pancreatitis (IEP).

Materials and Methods

Patients with IEP who underwent contrast-enhanced CT at admission and follow-up CT (< 14 days) were included (n = 178). Two radiologists performed a consensus review of follow-up CT scans and diagnosed the type of acute pancreatitis as IEP or NP. Laboratory findings at admission were recorded. Clinical, CT, and laboratory findings were compared between the IEP-IEP group and IEP-NP group using the chi-square test and the t-test. Multivariate analysis was also performed.

Results

There were 112 and 66 patients in the IEP-IEP and the IEP-NP groups, respectively. The proportion of patients with alcohol etiology was significantly larger in the IEP-NP group. Among the CT findings, the presence of peripancreatic fluid and heterogeneous parenchymal enhancement were more frequently observed in the IEP-NP group. Among the laboratory variables, serum C-reactive protein levels and white blood cell counts were significantly higher in the IEP-NP group. Multivariate analysis revealed that the presence of peripancreatic fluid and heterogeneous parenchymal enhancement were significant findings distinguishing the two groups.

Conclusion

CT findings, such as the presence of peripancreatic fluid and heterogeneous pancreatic parenchymal enhancement, may be helpful in predicting the progression to NP in patients initially diagnosed with IEP.

Assessing significant fibrosis using imaging-based elastography in chronic hepatitis B patients: Pilot study

BACKGROUND

Accurate detection of significant fibrosis (fibrosis stage 2 or higher on the METAVIR scale) is important especially for chronic hepatitis B (CHB) patients with high viral loads but with normal or mildly elevated alanine aminotransferase (ALT) levels because the presence of significant fibrosis is accepted as the indication for antiviral treatment. Liver biopsy is the reference standard for diagnosing significant fibrosis, but it is an invasive procedure. Consequently, noninvasive imaging-based measurements, such as magnetic resonance elastography (MRE) or two-dimensional shear-wave elastography (2D-SWE), have been proposed for the quantitative assessment of liver fibrosis.

AIM

To explore MRE and 2D-SWE to identify fibrosis stage, and to compare their performance with that of serum-based indices.

METHODS

The study enrolled 63 treatment-naïve CHB patients with high viral loads but with normal or mildly elevated ALT levels who underwent liver biopsy before a decision was made to initiate antiviral therapy. MRE and 2D-SWE were performed, and serum-based indices, such as FIB-4 and aspartate transaminase to platelet ratio index (APRI), were calculated. The diagnostic performances of MRE, 2D-SWE, FIB-4, and APRI for assessing significant fibrosis (≥ F2) and cirrhosis (F4) were evaluated with liver histology as the reference standard, using receiver operating characteristic analyses.

RESULTS

The liver fibrosis stage was F0/F1 in 19, F2 in 14, F3 in 14, and F4 in 16 patients, respectively. MRE significantly discriminated F2 from F0/1 (P = 0.022), whereas 2D-SWE showed a broad overlap in distinguishing those stages. MRE showed a higher correlation coefficient value with fibrosis stage than 2D-SWE with fibrosis stage (0.869 vs 0.649, Spearman test; P < 0.001). Multivariate linear regression analyses showed that fibrosis stage was the only factor affecting the values of MRE (P < 0.001), whereas body mass index (P = 0.042) and fibrosis stage (P < 0.001) were independent factors affecting 2D-SWE values. MRE performance for diagnosing significant fibrosis was better [area under the curve (AUC) = 0.906, positive predictive value (PPV) 97.3%, negative predictive value (NPV) 69.2%] than that of FIB-4 (AUC = 0.697, P = 0.002) and APRI (AUC = 0.717, P = 0.010), whereas the performance of 2D-SWE (AUC = 0.843, PPV 86%, NPV 65%) was not significantly different from that of FIB-4 or APRI.

CONCLUSION

Compared to SWE, MRE might be more precise non-invasive assessment for depicting significant fibrosis and for making-decision to initiate antiviral-therapy in treatment-naïve CHB patients with normal or mildly-elevated ALT levels.

Shrinkage of hepatocellular carcinoma after radiofrequency ablation following transcatheter arterial chemoembolization: Analysis of contributing factors

Objective

This study was conducted to investigate tumor shrinkage and influencing factors in patients with hepatocellular carcinoma (HCC) from radiofrequency (RF) ablation following transcatheter arterial chemoembolization (TACE).

Methods

A total of 222 patients underwent combined sequential treatment of TACE and RF ablation for HCC at our institution between 2008 and 2014. Of those, 86 patients (men, 68; women, 18) who achieved compact iodized oil tagging and complete ablation were included for this retrospective study. We measured three-dimensional tumor diameters and calculated tumor volumes on pre-treatment CT/MRI and follow-up CT scans performed post-TACE, post-ablation, and 1 month post-treatment, respectively. To compare periodically generated tumor diameters and volumes, repeated measures analysis of variance (ANOVA) was applied. Multiple linear regression analysis was performed to identify factors impacting tumor shrinkage after RF ablation.

Results

Diameters and volumes of HCCs declined significantly in the immediate aftermath of RF ablation (i.e., between post-TACE and post-ablation CT scans) (p < 0.001, for both). Mean reduction rates in tumor diameter and volume immediately after RF ablation were 18.2 ± 9.1% and 44.4 ± 14.6%, respectively. Of note, tumors of left hepatic lobe and in subphrenic or perivascular locations showed lower rates of post-ablative volume reduction than those in counterpart locations (p = 0.002, 0.046, 0.024, respectively). Tumor size and liver function did not influence tumor shrinkage after RF ablation.

Conclusion

In patients with HCC, significant tumor shrinkage occurs immediately after RF ablation. The degree of shrinkage in response to ablative treatment seems to vary by tumor location.

Low-Tube-Voltage CT Urography Using Low-Concentration-Iodine Contrast Media and Iterative Reconstruction: A Multi-Institutional Randomized Controlled Trial for Comparison with Conventional CT Urography

Objective

To compare the image quality of low-tube-voltage and low-iodine-concentration-contrast-medium (LVLC) computed tomography urography (CTU) with iterative reconstruction (IR) with that of conventional CTU.

Materials and Methods

This prospective, multi-institutional, randomized controlled trial was performed at 16 hospitals using CT scanners from various vendors. Patients were randomly assigned to the following groups: 1) the LVLC-CTU (80 kVp and 240 mgI/mL) with IR group and 2) the conventional CTU (120 kVp and 350 mgI/mL) with filtered-back projection group. The overall diagnostic acceptability, sharpness, and noise were assessed. Additionally, the mean attenuation, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and figure of merit (FOM) in the urinary tract were evaluated.

Results

The study included 299 patients (LVLC-CTU group: 150 patients; conventional CTU group: 149 patients). The LVLC-CTU group had a significantly lower effective radiation dose (5.73 ± 4.04 vs. 8.43 ± 4.38 mSv) compared to the conventional CTU group. LVLC-CTU showed at least standard diagnostic acceptability (score ≥ 3), but it was non-inferior when compared to conventional CTU. The mean attenuation value, mean SNR, CNR, and FOM in all pre-defined segments of the urinary tract were significantly higher in the LVLC-CTU group than in the conventional CTU group.

Conclusion

The diagnostic acceptability and quantitative image quality of LVLC-CTU with IR are not inferior to those of conventional CTU. Additionally, LVLC-CTU with IR is beneficial because both radiation exposure and total iodine load are reduced.

Multiparametric MR imaging of peripheral zone prostate cancer: effect of postbiopsy hemorrhage on cancer detection according to Gleason score and tumour volume

OBJECTIVE

To evaluate effect of postbiopsy hemorrhage on detection of peripheral zone (PZ) prostate cancer by multiparametric MR imaging according to Gleason score and tumor volume.

METHODS

This retrospective study included 54 biopsy-proven prostate cancer patients (median age, 67.0 years) who underwent multiparametric MR imaging. Two independent readers evaluated each sextant of the PZ using the PI-RADS v2. One reader recorded the presence or absence of hemorrhage per sextant on T₁ weighted MR images. Areas under the receiver operating characteristic curves (AUCs) were used to evaluate cancer detection accuracy.

RESULTS

Postbiopsy hemorrhage was noted in 122 (37.7%) of 324 sextants of all patients. There was no significant difference in the AUC for detection of cancer with Gleason score ≥3 + 4 or volume ≥0.5 ml between sextants with and without hemorrhage (with hemorrhage, reader 1, 0.83 for Gleason score ≥3 + 4, 0.84 for tumor volume ≥0.5 ml; reader 2, 0.74 for Gleason score ≥3 + 4, 0.77 for tumor volume ≥0.5 ml; without hemorrhage, reader 1, 0.86 for Gleason score ≥3 + 4, 0.88 for tumor volume ≥0.5 ml; reader 2, 0.79 for Gleason score ≥3 + 4, 0.83 for tumor volume ≥0.5 ml; p > 0.2 for all).

CONCLUSION

Postbiopsy hemorrhage did not negatively affect the detection of clinically significant PZ prostate cancer on multiparametric MR imaging. Advances in knowledge: Under influence of postbiopsy hemorrhage, multiparametric MR can be useful for the detection of clinically significant PZ prostate cancer.

Visibility of focal liver lesions: Comparison between kupffer phase of CEUS with sonazoid and hepatobiliary phase of gadoxetic acid-enhanced MRI

BACKGROUND

To investigate the agreement between Kupffer phase of Sonazoid contrast-enhanced sonography (CEUS) and hepatobiliary phase of gadoxetic acid-enhanced MRI in the evaluation of focal liver lesions (FLLs).

METHODS

One hundred fifty-four FLLs in 154 patients who underwent both Sonazoid CEUS and gadoxetic acid-enhanced liver MRI were included in this retrospective study. FLL visibility on the Kupffer-phase images was graded as one (invisible or isoenhancing), two (vaguely visible or vaguely hypoenhancing), or three (clearly visible or clearly hypoenhancing), and that on the hepatobiliary-phase images of MRI was graded as one (invisible or hyper/isointense), two (vaguely visible or weakly hypointense), or three (clearly visible or strongly hypointense). Pairwise comparison of lesion visibility between the two modalities was performed, and intermodality agreement was assessed.

RESULTS

On Kupffer-phase CEUS, 31 (20.1%) lesions were invisible, 17 (11.1%) were vaguely visible, and 106 (68.9%) were clearly visible. On the hepatobiliary-phase MRI, 9 (5.9%) lesions were invisible, 45 (29.2%) were vaguely visible, and 100 (64.9%) were clearly visible. Overall, lesion visibility scores were not significantly different between the two modalities (p = 0.121), but the visibility was significantly better on MRI in smaller lesions. Twenty-eight lesions (18.2%) showed discrepancy in the visibility on CEUS and MRI, and most of the cases (89.7%) were lesions that were invisible on CEUS but visible on MRI.

CONCLUSIONS

The overall visibility of FLLs was comparable between the Kupffer phase of Sonazoid-CEUS and the hepatobiliary-phase images of gadoxetic acid-enhanced MRI, with a discrepancy between the two modalities in 18% of the cases. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 45:542-550, 2017.

Radiofrequency ablation of benign thyroid nodules: depicting early sign of regrowth by calculating vital volume

OBJECTIVE

We evaluated long-term follow-up results of radiofrequency ablation of benign thyroid nodules to analyse the role of marginal vital tissue on nodule regrowth.

MATERIALS AND METHODS

We reviewed the medical records of 54 patients who underwent radiofrequency ablation between June 2008 and November 2013 with pressure symptoms, and/or cosmetic problems. All patients were followed up at least 12 months on three occasions. To evaluate an early sign of regrowth, three types of nodule volumes (total volume, ablated volume and vital volume) were measured and calculated using ultrasonography. Regrowth was defined as a more than a 50% increase in the total volume and vital volume increase was defined as a more than 50% increase compared to the previously reported smallest volume on ultrasonography.

RESULTS

The mean follow-up period was 39.4 ± 21.7 (range, 13-87) months. Vital volume increases occurred in 31 nodules (57.4%) and there was regrowth in 13 nodules (24.1%). The mean timing of the vital volume increase was 27.5 ± 18.5 months, and for regrowth it was 39.9 ± 17.5 months. Vital volume increase tended to precede regrowth.

CONCLUSION

Vital volume increase tended to occur earlier than regrowth and might be an early sign of regrowth in following-up after the radiofrequency ablation of benign thyroid nodules.

Imaging Patterns of Intratumoral Calcification in the Abdominopelvic Cavity

Intratumoral calcification is one of the most noticeable of radiologic findings. It facilitates detection and provides information important for correctly diagnosing tumors. In the abdominopelvic cavity, a wide variety of tumors have calcifications with various imaging features, though the majority of such calcifications are dystrophic in nature. In this article, we classify the imaging patterns of intratumoral calcification according to number, location, and morphology. Then, we describe commonly-encountered abdominopelvic tumors containing typical calcification patterns, focusing on their differentiable characteristics using the imaging patterns of intratumoral calcification.

Validation of the Korean-Version of the Clinical Assessment Interview for Negative Symptoms of Schizophrenia (CAINS)

The Clinical Assessment Interview for Negative Symptoms (CAINS) was developed to overcome the limitations of existing instruments and reflect the current view of negative symptoms. The aim of the present study was to evaluate the reliability and validity of the Korean version of the Clinical Assessment Interview for Negative Symptoms (K-CAINS). Inpatients (n = 49) and outpatients (n = 70) with schizophrenia were recruited from three institutions. The confirmative factor analysis, test-retest reliability, inter-rater reliability, convergent validity, and discriminant validity were assessed. The study group consisted of 71 males (59.7%) and 48 females (40.3%). Their mean age was 42.15 years (SD = 12.2). The K-CAINS was confirmed to be divided into two subscales of 9 items related to "motivation/pleasure" and 4 items related to "expression" in concordance with the original version of the CAINS. The results showed that the K-CAINS had a good inter-rater reliability (ICC = 0.84-0.94), test-retest reliability (r = 0.90, P < 0.001). Convergent validity was proven by demonstrating a significant correlation with the Positive and Negative Syndrome Scale (PANSS) negative subscale, and the Scale for the Assessment of Negative Symptoms (SANS). Discriminant validity was proven by the lack of a significant correlation with the PANSS positive subscale, the Korean version of the Beck depression inventory (BDI), the Korean version of the Calgary depression scale for schizophrenia (K-CDSS), and the Modified Simpson Angus scale (MSAS). The K-CAINS could be a reliable and valid tool to assess the negative symptoms of Korean schizophrenia patients.

Added Value of Using a CT Coronal Reformation to Diagnose Adnexal Torsion

Objective

To evaluate the increased value of using coronal reformation of a transverse computed tomography (CT) scan for detecting adnexal torsion.

Materials and Methods

This study included 106 woman suspected of having adnexal torsion who underwent CT with coronal reformations and subsequent surgical exploration. Two readers independently recorded the CT findings, such as the thickening of a fallopian tube, twisting of the adnexal pedicle, eccentric smooth wall thickening of the torsed adnexal mass, eccentric septal thickening of the torsed adnexal mass, eccentric poor enhancement of the torsed adnexal mass, uterine deviation to the twisted side, ascites or infiltration of pelvic fat, and the overall impression of adnexal torsion with a transverse scan alone or combined with coronal reformation and a transverse scan. The areas under the receiver operating characteristic curves (AUCs), sensitivity, specificity, and positive predictive value were used to compare diagnostic performance.

Results

Fifty-two patients were confirmed to have adnexal torsion. The addition of coronal reformations to the transverse scan improved AUCs for readers 1 and 2 from 0.74 and 0.75 to 0.92 and 0.87, respectively, for detecting adnexal torsion (p < 0.001 and p = 0.004, respectively). Sensitivity of CT for detecting twisting of the adnexal pedicle increased significantly for readers 1 and 2 from 0.27 and 0.29 with a transverse scan alone to 0.79 and 0.77 with a combined coronal reformation and a transverse scan, respectively (p < 0.001 and p < 0.001, respectively).

Conclusion

Use of a coronal reformation with transverse CT images improves detection of adnexal torsion.

Diagnosis of esophageal varices on liver CT: is thin-section reconstruction necessary?

BACKGROUND/AIMS

The aim of this study was to evaluate the effect of 1 mm, 3 mm, and 5 mm section thicknesses of liver CT on the detection and grading of esophageal varices in cirrhotic patients.

METHODOLOGY

A total of 219 consecutive cirrhotic patients who had undergone both upper endoscopy and 64-channel liver CT were included. Portal phase images of each CT were reconstructed with a section thickness of 1 mm, 3 mm, and 5 mm. Four radiologists independently reviewed the 3 image sets. The observers evaluated the presence of esophageal varices on a 5-point confidence scale and measured the maximal short diameter of the largest varix identified. Sensitivity, specificity and predictive value calculation and receiver operating characteristic analysis were performed. Correlation between CT measurements and endoscopic grading as the reference standard was assessed.

RESULTS

The averaged Az values at 1 mm, 3 mm, and 5 mm image sets were 0.936, 0.946, and 0.935, respectively, and they were not significantly different among the 4 observers. When a 3 mm cut-off criterion for large varices was applied, sensitivity, specificity, and predictive values were comparable among the 3 image datasets.

CONCLUSIONS

Routine liver CT protocol is sufficient for evaluation of esophageal varices in cirrhotic patients without adding thin section reconstruction images.

Real-time contrast-enhanced sonographically guided biopsy or radiofrequency ablation of focal liver lesions using perflurobutane microbubbles (sonazoid): value of Kupffer-phase imaging

OBJECTIVES

To evaluate the utility of Kupffer-phase imaging by real-time contrast-enhanced sonography using the perflurobutane microbubble contrast agent Sonazoid (GE Healthcare, Oslo, Norway) in guiding biopsy or radiofrequency (RF) ablation of focal liver lesions.

METHODS

A total of 75 patients (mean age, 59.7 years) who were referred for percutaneous biopsy (n = 42) or RF ablation (n = 33) were included in the study. Grayscale sonography and contrast-enhanced sonography using Sonazoid were performed in all patients before the procedure. The conspicuity of each targeted liver lesion on grayscale sonography, vascular-phase contrast-enhanced sonography, and Kupffer-phase contrast-enhanced sonography was graded using a 5-point scale. Lesion detection rates were calculated, and the conspicuity of the lesions among the imaging modalities was compared. The technical success of the procedures was also assessed.

RESULTS

The procedures were conducted in 66 patients (biopsy in 41 and RF ablation in 25) under real-time guidance by Kupffer-phase contrast-enhanced sonography. Lesion detection rates were 77.3% (58 of 75), 84.0% (63 of 75), and 92.0% (69 of 75) on grayscale sonography, vascular-phase contrast-enhanced sonography, and Kupffer-phase contrast-enhanced sonography, respectively, and were significantly different among the 3 modalities (P= .034). Overall, lesion conspicuity was significantly increased on vascular-phase and Kupffer-phase contrast-enhanced sonography compared to grayscale sonography (P < .001). Technical success rates for the procedures were 95.2% (40 of 42) for biopsy and 69.7% (23 of 33) for RF ablation.

CONCLUSIONS

Kupffer-phase imaging by contrast-enhanced sonography using Sonazoid increases the conspicuity of the liver lesions compared to grayscale sonography, and it is useful for real-time guidance of percutaneous biopsy or RF ablation of focal liver lesions.

Ultrasonography of ovarian masses using a pattern recognition approach

As a primary imaging modality, ultrasonography (US) can provide diagnostic information for evaluating ovarian masses. Using a pattern recognition approach through gray-scale transvaginal US, ovarian masses can be diagnosed with high specificity and sensitivity. Doppler US may allow ovarian masses to be diagnosed as benign or malignant with even greater confidence. In order to differentiate benign and malignant ovarian masses, it is necessary to categorize ovarian masses into unilocular cyst, unilocular solid cyst, multilocular cyst, multilocular solid cyst, and solid tumor, and then to detect typical US features that demonstrate malignancy based on pattern recognition approach.

Volume and landmark analysis: comparison of MRI measurements obtained with an endorectal coil and with a phased-array coil

AIM

To compare prostate volumes and distances between anatomical landmarks on MRI images obtained with a phased-array coil (PAC) only and with a PAC and an endorectal coil (ERC).

MATERIALS AND METHODS

Informed consent was waived for this Health Insurance Portability and Accountability Act-compliant study. Fifty-nine men underwent PAC-MRI and ERC-MRI at 1.5 (n = 3) or 3 T (n = 56). On MRI images, two radiologists independently measured prostate volume and distances between the anterior rectal wall (ARW) and symphysis pubis at the level of the verumontanum; ARW and symphysis pubis at the level of the mid-symphysis pubis; and bladder neck and mid-symphysis pubis. Differences between measurements from PAC-MRI and ERC-MRI were assessed with the Wilcoxon RANK SUM test. Inter-reader agreement was assessed using the concordance correlation coefficient (CCC).

RESULTS

Differences in prostate volume between PAC-MRI and ERC-MRI [median: -0.75 mm(3) (p = 0.10) and median: -0.84 mm(3) (p = 0.06) for readers 1 and 2, respectively] were not significant. For readers 1 and 2, median differences between distances were as follows: -10.20 and -12.75 mm, respectively, ARW to symphysis pubis at the level of the verumontanum; -6.60 and -6.08 mm, respectively, ARW to symphysis pubis at the level of the mid-symphysis pubis; -3 and -3 mm respectively, bladder neck to mid-symphysis pubis. All differences in distance were significant for both readers (p ≤ 0.0005). Distances were larger on PAC-MRI (p ≤ 0.0005). Inter-reader agreement regarding prostate volume was almost perfect on PAC-MRI (CCC: 0.99; 95% CI: 0.98-1.00) and ERC-MRI (CCC: 0.99; 95% CI: 0.99-1.00); inter-reader agreement for distance measurements varied (CCCs: 0.54-0.86).

CONCLUSION

Measurements of distances between anatomical landmarks differed significantly between ERC-MRI and PAC-MRI, although prostate volume measurements did not.

Three-Tesla magnetic resonance elastography for hepatic fibrosis: Comparison with diffusion-weighted imaging and gadoxetic acid-enhanced magnetic resonance imaging

AIM: To evaluate the feasibility of 3-Tesla magnetic resonance elastography (MRE) for hepatic fibrosis and to compare that with diffusion-weighted imaging (DWI) and gadoxetic acid-enhanced magnetic resonance (MR) imaging.

METHODS: Forty-two patients were included in the study. On MRE, mean stiffness values were measured on the elastograms in kilopascals. The apparent diffusion coefficient (ADC) of the liver was measured using DWI. On gadoxetic acid enhanced MR, the contrast enhancement index (CEI) was calculated as signal intensity (SI)_post/SI_pre, where SI_post is liver-to-muscle SI ratio on hepatobiliary phase images and SI_pre is that on nonenhanced images. Correlation between aspartate aminotransferase to the platelet ratio index (APRI) and three MR parameters was assessed. Each MR parameter was compared between a hepatic fibrosis (HF) group and non-hepatic fibrosis (nHF) group.

RESULTS: Liver stiffness showed strong positive correlation with APRI [Spearman correlation coeffiecient (r) = 0.773, P < 0.0001], while ADC and CEI showed weak or prominent negative correlation (r = -0.28 and -0.321, respectively). In the HF group, only liver stiffness showed strong correlation with APRI (r = 0.731, P < 0.0001). Liver stiffness, ADC, and APRI were significantly different between the HF group and nHF group.

CONCLUSION: MRE at 3-Tesla could be a feasible method for the assessment of hepatic fibrosis.

Contrast-induced nephropathy in patients undergoing intravenous contrast-enhanced computed tomography in Korea: a multi-institutional study in 101487 patients

Objective

To evaluate the prevalence of known risk factors for contrast-induced nephropathy (CIN) and their association with the actual occurrence of CIN in patients undergoing intravenous contrast-enhanced computed tomography (CECT) in Korea.

Materials and Methods

Patients who underwent CECT in 2008 were identified in the electronic medical records of 16 tertiary hospitals of Korea. Data on demographics, comorbidities, prescriptions and laboratory test results of patients were collected following a standard data extraction protocol. The baseline renal function was assessed using the estimated glomerular filtration rate (eGFR). We identified the prevalence of risk factors along the eGFR strata and evaluated their influence on the incidence of CIN, defined as a 0.5 mg/dL or 25% increase in serum creatinine after CECT.

Results

Of 432425 CECT examinations in 272136 patients, 140838 examinations in 101487 patients met the eligibility criteria for analysis. The mean age of the participants was 57.9 ± 15.5 years; 25.1% of the patients were older than 70 years. The prevalence of diabetes mellitus was 11.9%, of hypertension 13.7%, of gout 0.55% and of heart failure was 1.7%. Preventive measures were used in 40238 CECT examinations (28.6%). The prevalence of risk factors and use of preventive measures increased as the renal function became worse. A CIN was occurred after 3103 (2.2%) CECT examinations, revealing a significant association with decreased eGFR, diabetes mellitus, and congestive heart failure after adjustment.

Conclusion

Risk factors for CIN are prevalent among the patients undergoing CECT. Preventive measures were seemingly underutilized and a system is needed to improve preventive care.

Unenhanced CT for the detection of renal cell carcinoma: effect of tumor size and contour type

PURPOSE

To evaluate effect of tumor size and contour type for the detection of renal cell carcinoma (RCC) on unenhanced CT.

METHODS

This retrospective institutional review board approved study that includes 111 patients with RCC and 100 patients without RCC who underwent unenhanced CT. Two readers performed a blinded and independent review of the presence of RCC on unenhanced CT. The area under the receiver operating characteristic curves (AUC) was compared by tumor size (<3 cm: small, or ≥3 cm: large) and contour type (endophytic, mesophytic, or exophytic).

RESULTS

For tumor size, the AUC for small RCC (0.70 and 0.78, for reader 1 and reader 2) was significantly lower than that for large RCC (0.97 and 0.99, for reader 1 and reader 2) (p < 0.001). As for contour type of tumor, the AUC for endophytic RCC (0.60 and 0.71, for reader 1 and reader 2) was significantly lower than that for mesophytic RCC (0.95 and 0.98, for reader 1 and reader 2) and exophytic RCC (0.98 and 0.99, reader 1 and reader 2) (p < 0.001).

CONCLUSION

On unenhanced CT, tumor size and contour type can affect the detection of RCC. While most large or exophytic RCC can be easily detected, the detection of small and endophytic RCC is highly limited.

Multidetector computed tomography for the assessment of adnexal mass: is unenhanced CT scan necessary?

OBJECTIVE

To compare the diagnostic performance and radiation dose between contrast-enhanced CT (ECT) alone, and combined unenhanced and contrast-enhanced CT (UE + ECT) for the assessment of adnexal mass.

MATERIALS AND METHODS

This retrospective study was approved by the Institutional Review Board. A total of 146 consecutive patients (mean age, 41.1 years) who underwent preoperative unenhanced and contrast-enhanced multidetector CT of the pelvis and had adnexal masses found at surgery were included. Two readers independently evaluated the likelihood of adnexal malignancy on a 5-point scale on two different imaging datasets (ECT alone and UE + ECT). The area under the receiver operating characteristic curve (AUC) was used to evaluate diagnostic performance. Radiation dose to patients was calculated by the volume CT dose index (CTDIvol) and the dose length products (DLP) on each dataset.

RESULTS

Of the total 178 adnexal masses, 133 masses were benign and 45 masses were malignant. For both readers, there is no significant difference of AUC values between ECT alone and UE + ECT for the detection of adnexal malignancy (reader 1, 0.93 vs. 0.95; reader 2, 0.92 vs. 0.91) (p > 0.05). The mean CTDIvol (12.6 ± 2.2 mGy) and DLP (641.2 ± 137.2 mGy) of ECT alone was significantly lower than the mean CTDIvol (21.5 ± 2.7 mGy) and DLP (923.6 ± 158.8 mGy) of UE + ECT (p < 0.0001).

CONCLUSION

The use of unenhanced CT scan in addition to contrast-enhanced CT scan does not improve the detection of adnexal malignancy, but increases radiation exposure.

Transition zone prostate cancer: incremental value of diffusion-weighted endorectal MR imaging in tumor detection and assessment of aggressiveness

PURPOSE

To evaluate the incremental value of using diffusion-weighted magnetic resonance (MR) imaging in addition to T2-weighted imaging for the detection of prostate cancer in the transition zone and the assessment of tumor aggressiveness.

MATERIALS AND METHODS

This retrospective HIPAA-compliant institutional review board-approved study included 156 consecutive patients (median age, 59.2 years) who underwent MR imaging before radical prostatectomy. Two readers who were blinded to patient data independently recorded their levels of suspicion on a five-point scale of the presence of transition zone tumors on the basis of T2-weighted imaging alone and then, 4 weeks later, diffusion-weighted imaging and T2-weighted imaging together. Apparent diffusion coefficients (ADCs) were measured in transition zone cancers and glandular and stromal benign prostatic hyperplasia. Areas under the receiver operating characteristic curves were used to evaluate detection accuracy, and generalized linear models were used to test ADC differences between benign and malignant prostate regions. Whole-mount step-section histopathologic examination was the reference standard.

RESULTS

In overall tumor detection, addition of diffusion-weighted imaging to T2-weighted imaging improved the areas under the receiver operating characteristic curves for readers 1 and 2 from 0.60 and 0.60 to 0.75 and 0.71, respectively, at the patient level (P = .004 for reader 1 and P = .027 for reader 2) and from 0.64 and 0.63 to 0.73 and 0.68, respectively, at the sextant level (P = .001 for reader 1 and P = .100 for reader 2). Least squares mean ADCs (× 10(-3) mm(2)/sec) in glandular and stromal benign prostatic hyperplasia were 1.44 and 1.09, respectively. Mean ADCs were inversely associated with tumor Gleason scores (1.10, 0.98, 0.87, and 0.75 for Gleason scores of 3 + 3, 3 + 4, 4 + 3, and ≥ 4 + 4, respectively).

CONCLUSION

Use of diffusion-weighted imaging in addition to T2-weighted imaging improved detection of prostate cancer in the transition zone, and tumor ADCs were inversely associated with tumor Gleason scores in the transition zone.

Transition zone prostate cancer: incremental value of diffusion-weighted endorectal MR imaging in tumor detection and assessment of aggressiveness

PURPOSE

To evaluate the incremental value of using diffusion-weighted magnetic resonance (MR) imaging in addition to T2-weighted imaging for the detection of prostate cancer in the transition zone and the assessment of tumor aggressiveness.

MATERIALS AND METHODS

This retrospective HIPAA-compliant institutional review board-approved study included 156 consecutive patients (median age, 59.2 years) who underwent MR imaging before radical prostatectomy. Two readers who were blinded to patient data independently recorded their levels of suspicion on a five-point scale of the presence of transition zone tumors on the basis of T2-weighted imaging alone and then, 4 weeks later, diffusion-weighted imaging and T2-weighted imaging together. Apparent diffusion coefficients (ADCs) were measured in transition zone cancers and glandular and stromal benign prostatic hyperplasia. Areas under the receiver operating characteristic curves were used to evaluate detection accuracy, and generalized linear models were used to test ADC differences between benign and malignant prostate regions. Whole-mount step-section histopathologic examination was the reference standard.

RESULTS

In overall tumor detection, addition of diffusion-weighted imaging to T2-weighted imaging improved the areas under the receiver operating characteristic curves for readers 1 and 2 from 0.60 and 0.60 to 0.75 and 0.71, respectively, at the patient level (P = .004 for reader 1 and P = .027 for reader 2) and from 0.64 and 0.63 to 0.73 and 0.68, respectively, at the sextant level (P = .001 for reader 1 and P = .100 for reader 2). Least squares mean ADCs (× 10(-3) mm(2)/sec) in glandular and stromal benign prostatic hyperplasia were 1.44 and 1.09, respectively. Mean ADCs were inversely associated with tumor Gleason scores (1.10, 0.98, 0.87, and 0.75 for Gleason scores of 3 + 3, 3 + 4, 4 + 3, and ≥ 4 + 4, respectively).

CONCLUSION

Use of diffusion-weighted imaging in addition to T2-weighted imaging improved detection of prostate cancer in the transition zone, and tumor ADCs were inversely associated with tumor Gleason scores in the transition zone.

Focal nodular hyperplasia: characterisation at gadoxetic acid-enhanced MRI and diffusion-weighted MRI

PURPOSE

The aim of this study was to assess the enhancement patterns of hepatic focal nodular hyperplasia (FNH) on gadoxetic acid-enhanced MRI and diffusion-weighted (DW) MRI.

METHODS

This retrospective study had institutional review board approval. Gadoxetic acid-enhanced and DW MR images were evaluated in 23 patients with 30 FNHs (26 histologically proven and 4 radiologically diagnosed). The lesion enhancement patterns of the hepatobiliary phase images were classified as heterogeneous or homogeneous signal intensity (SI), and as dominantly high/iso or low SI compared with those of adjacent liver parenchyma. Heterogeneous (any) SI lesions and homogeneous low SI lesions were categorised into the fibrosis group, whereas homogeneous high/iso SI lesions were categorised into the non-fibrosis group. Additionally, lesion SI on T2 weighted images, DW images and apparent diffusion coefficient (ADC) values were compared between the two groups.

RESULTS

The lesions showed heterogeneous high/iso SI (n=16), heterogeneous low SI (n=5), homogeneous high/iso SI (n=7) or homogeneous low SI (n=2) at the hepatobiliary phase MR images. The fibrosis group lesions were more likely to show high SI on DW images and T2 weighted images compared with those in the non-fibrosis group (p<0.05). ADC values tended to be lower in the fibrosis group than those in the non-fibrosis group without significance.

CONCLUSION

FNH showed variable enhancement patterns on hepatobiliary phase images during gadoxetic acid-enhanced MRI. SI on DW and T2 weighted images differed according to the fibrosis component contained in the lesion.

ADVANCES IN KNOWLEDGE

FNH shows a wide spectrum of imaging findings on gadoxetic acid-enhanced MRI and DW MRI.

Multiparametric prostate MR imaging with T2-weighted, diffusion-weighted, and dynamic contrast-enhanced sequences: are all pulse sequences necessary to detect locally recurrent prostate cancer after radiation therapy?

PURPOSE

To compare diagnostic accuracy of T2-weighted magnetic resonance (MR) imaging with that of multiparametric (MP) MR imaging combining T2-weighted imaging with diffusion-weighted (DW) MR imaging, dynamic contrast material-enhanced (DCE) MR imaging, or both in the detection of locally recurrent prostate cancer (PCa) after radiation therapy (RT).

MATERIALS AND METHODS

This retrospective HIPAA-compliant study was approved by the institutional review board; informed consent was waived. Fifty-three men (median age, 70 years) suspected of having post-RT recurrence of PCa underwent MP MR imaging, including DW and DCE sequences, within 6 months after biopsy. Two readers independently evaluated the likelihood of PCa with a five-point scale for T2-weighted imaging alone, T2-weighted imaging with DW imaging, T2-weighted imaging with DCE imaging, and T2-weighted imaging with DW and DCE imaging, with at least a 4-week interval between evaluations. Areas under the receiver operating characteristic curve (AUC) were calculated. Interreader agreement was assessed, and quantitative parameters (apparent diffusion coefficient [ADC], volume transfer constant [K(trans)], and rate constant [k(ep)]) were assessed at sextant- and patient-based levels with generalized estimating equations and the Wilcoxon rank sum test, respectively.

RESULTS

At biopsy, recurrence was present in 35 (66%) of 53 patients. In detection of recurrent PCa, T2-weighted imaging with DW imaging yielded higher AUCs (reader 1, 0.79-0.86; reader 2, 0.75-0.81) than T2-weighted imaging alone (reader 1, 0.63-0.67; reader 2, 0.46-0.49 [P ≤ .014 for all]). DCE sequences did not contribute significant incremental value to T2-weighted imaging with DW imaging (reader 1, P > .99; reader 2, P = .35). Interreader agreement was higher for combinations of MP MR imaging than for T2-weighted imaging alone (κ = 0.34-0.63 vs κ = 0.17-0.20). Medians of quantitative parameters differed significantly (P < .0001 to P = .0233) between benign tissue and PCa (ADC, 1.64 × 10(-3) mm(2)/sec vs 1.13 × 10(-3) mm(2)/sec; K(trans), 0.16 min(-1) vs 0.33 min(-1); k(ep), 0.36 min(-1) vs 0.62 min(-1)).

CONCLUSION

MP MR imaging has greater accuracy in the detection of recurrent PCa after RT than T2-weighted imaging alone, with no additional benefit if DCE is added to T2-weighted imaging and DW imaging.

Sonographic findings of ectopic prostatic tissue in the bladder: a case report and review of the literature

Ectopic prostatic tissue in the bladder has rarely been reported, and there is currently no report about the sonographic findings of this entity. In this study, we present the imaging findings of ectopic prostatic tissue in the bladder on transrectal ultrasonography.

Interventional management for complications following caesarean section

OBJECTIVES

This study aimed to evaluate the efficacy and safety of interventional management for various intractable complications following caesarean section.

METHODS

Between August 2005 and September 2009, 18 consecutive women were referred to interventional radiology for treatment of complications developing after caesarean section. Complications included vaginal bleeding (n = 14), haemoperitoneum with abdominal wall haematoma (n = 2), caesarean scar pregnancy (CSP) (n = 1) and post-caesarean fluid collection (n = 1).

RESULTS

17 women underwent transcatheter arterial embolisation (TAE) with a variety of embolic materials, and two women underwent percutaneous drainage (PCD) for fluid collection and haemoperitoneum. 5 of the 14 women with vaginal bleeding had extravasation of contrast media on angiography; the other 9 had no visible bleeding foci. The two women with haemoperitoneum with abdominal wall haematoma had injury to the inferior epigastric artery from angiography. TAE and PCD were successfully performed in both women. The CSP was successfully managed and the serum β-human chorionic gonadotropin (β-hCG) level finally normalised. Hysterectomy or dilatation and curretage was required in women with placenta accrete and undetectable bleeding foci.

CONCLUSION

Interventional management including TAE and PCD is effective and safe in controlling complications following caesarean section. Use of these procedures can help avoid high-risk surgery, but subsequent procedures including hysterectomy may be required in cases of placental abnormalities and undetectable bleeding foci.

Sequential changes in echogenicity and conspicuity of small hepatocellular carcinoma on gray scale sonography after transcatheter arterial chemoembolization

OBJECTIVE

The purpose of this study was to assess sequential changes in the echogenicity and conspicuity of small hepatocellular carcinoma (HCC) after transcatheter arterial chemoembolization (TACE).

METHODS

Seventy patients with nodular HCC underwent 3 serial abdominal sonographic examinations before (t0), immediately after (t1), and 2 to 4 days after (t2) TACE. The echogenicity and conspicuity of the HCC nodules were prospectively graded using a 5-point scale. For all tumors, any changes in the echogenicity and conspicuity scores obtained at t0, t1, and t2 were evaluated. The degree of intratumoral uptake of iodized oil was categorized as compact or noncompact based on unenhanced computed tomographic images. Within each group, the sequential changes in the echogenicity and conspicuity were analyzed. Cross-sectional comparisons of the echogenicity and conspicuity at each time point between the two groups were also made.

RESULTS

Overall, the lesion echogenicity and conspicuity at t1 increased compared with those at t0 (P < .05). Thereafter, both the echogenicity and conspicuity at t2 decreased compared with those at t1 (P < .05). There were 41 HCC nodules with compact iodized oil uptake and 29 with noncompact uptake. Significant sequential changes in the echogenicity (increase at t1 followed by decrease at t2) were noted in both groups, but only the compact group showed a significant change in conspicuity. In a cross-sectional comparison, the compact group showed higher scores for both echogenicity and conspicuity than the noncompact group at both t1 and t2 (P < .05).

CONCLUSIONS

The echogenicity and conspicuity of HCC are increased immediately after TACE. These effects are significantly diminished 2 to 4 days after TACE.

Multiple, bilateral fibroepithelial polyps causing acute renal failure in a gastric cancer patient

We report a case of primary fibroepithelial polyps (FEPs) in the middle of both ureters in a patient with advanced gastric cancer and acute renal failure. Ureteral FEPs are rare benign lesions, and multiple, bilateral lesions are extremely rare. To our knowledge, this report is the seventh case of bilateral FEPs in the literature. Our case has clinical implications because FEPs should be considered as a cause of ureteral obstruction inducing acute renal failure in advanced gastric cancer.

Dual-modal nanoprobes for imaging of mesenchymal stem cell transplant by MRI and fluorescence imaging

Objective

To determine the feasibility of labeling human mesenchymal stem cells (hMSCs) with bifunctional nanoparticles and assessing their potential as imaging probes in the monitoring of hMSC transplantation.

Materials and Methods

The T1 and T2 relaxivities of the nanoparticles (MNP@SiO₂[RITC]-PEG) were measured at 1.5T and 3T magnetic resonance scanner. Using hMSCs and the nanoparticles, labeling efficiency, toxicity, and proliferation were assessed. Confocal laser scanning microscopy and transmission electron microscopy were used to specify the intracellular localization of the endocytosed iron nanoparticles. We also observed in vitro and in vivo visualization of the labeled hMSCs with a 3T MR scanner and optical imaging.

Results

MNP@SiO₂(RITC)-PEG showed both superparamagnetic and fluorescent properties. The r₁ and r₂ relaxivity values of the MNP@SiO₂(RITC)-PEG were 0.33 and 398 mM^-1 s^-1 at 1.5T, respectively, and 0.29 and 453 mM^-1 s^-1 at 3T, respectively. The effective internalization of MNP@SiO₂(RITC)-PEG into hMSCs was observed by confocal laser scanning fluorescence microscopy. The transmission electron microscopy images showed that MNP@SiO₂(RITC)-PEG was internalized into the cells and mainly resided in the cytoplasm. The viability and proliferation of MNP@SiO₂(RITC)-PEG-labeled hMSCs were not significantly different from the control cells. MNP@SiO₂(RITC)-PEG-labeled hMSCs were observed in vitro and in vivo with optical and MR imaging.

Conclusion

MNP@SiO₂(RITC)-PEG can be a useful contrast agent for stem cell imaging, which is suitable for a bimodal detection by MRI and optical imaging.

Percutaneous radiofrequency ablation of small hepatocellular carcinoma invisible on both ultrasonography and unenhanced CT: a preliminary study of combined treatment with transarterial chemoembolisation

The purpose of this study was to assess the feasibility and efficacy of percutaneous radiofrequency ablation combined with transarterial chemoembolisation (TACE) for the treatment of hepatocellular carcinoma that are invisible on both ultrasound and unenhanced CT. 73 patients with a total of 101 nodular hepatocellular carcinomas were referred for possible radiofrequency (RF) ablation. Of these, 14 lesions (14%) in 14 patients were invisible on both ultrasound and unenhanced CT. The invisible nodules averaged 1.2 cm in diameter (range, 0.8-2.0 cm; median, 1.1 cm). After segmental TACE, percutaneous RF ablation was performed if the index tumour was visible on fluoroscopy, ultrasound or CT. All cases of combined treatment were evaluated for size of ablative zone, complications, rate of technical effectiveness at 1-month follow-up CT and local tumour progression. After TACE, percutaneous RF ablation was technically feasible in 10 (71%) of the 14 nodules. RF ablation was performed with the guidance of fluoroscopy (n = 6, 42%), ultrasound (n = 2, 14%) or CT (n = 2, 14%). The mean diameter of the ablative zone by percutaneous RF ablation combined with TACE was 4.8+/-0.7 cm and 3.4+/-0.6 cm in the long and short axis, respectively. No major complications were documented. The primary technical effectiveness rate for nodules treated by combined treatment was 100% (10/10) at 1-month follow-up CT. No local tumour progression was found during the follow-up period (median 15 months; range 4-20 months). Percutaneous RF ablation combined with TACE is a feasible and effective technique for treating small hepatocellular carcinomas that are not visible on ultrasound or unenhanced CT.

In vivo MR imaging of magnetically labeled mesenchymal stem cells in a rat model of renal ischemia

Objective

This study was designed to evaluate in vivo MR imaging for the depiction of intraarterially injected superparamagnetic iron oxide (SPIO)-labeled mesenchymal stem cells (MSCs) in an experimental rat model of renal ischemia.

Materials and Methods

Left renal ischemia was induced in 12 male Sprague-Dawley rats by use of the catheter lodging method. In vivo MR signal intensity variations depicted on T2*-weighted sequences were evaluated in both the left and right kidneys prior to injection (n = 2), two hours (n = 4), 15 hours (n = 2), 30 hours (n = 2) and 72 hours (n = 2) after injection of SPIO-labeled MSCs in both kidneys. Signal intensity variations were correlated with the number of Prussian blue stain-positive cells as visualized in histological specimens.

Results

In an in vivo study, it was determined that there was a significant difference in signal intensity variation for both the left and right cortex (40.8 ± 4.12 and 26.4 ± 7.92, respectively) and for both the left and right medulla (23.2 ± 3.32 and 15.2 ± 3.31, respectively) until two hours after injection (p < 0.05). In addition, signal intensity variation in the left renal cortex was well correlated with the number of Prussian blue stain-positive cells per high power field (r = 0.98, p < 0.05).

Conclusion

Intraarterial injected SPIO-labeled MSCs in an experimental rat model of renal ischemia can be detected with the use of in vivo MR imaging immediately after injection.

Characteristic sonographic vesicular pattern of a complete hydatidiform mole in the early first trimester

OBJECTIVE

To evaluate the sonographic vesicular pattern of a complete hydatidiform mole (CHM) in the early first trimester.

STUDY DESIGN

A retrospective study was performed on 30 cases of histologically proven CHMs in the early first trimester. Two radiologists reviewed the sonograms of all cases before evacuation and determined the extent of vesicular pattern for each case independently. The extent of vesicular area was divided into 4 categories: absent, mild (less than one third), moderate (one third to two thirds) or severe (more than two thirds). Interobserver agreement between the reviewers was calculated by weighted kappa.

RESULTS

The mean gestational age of all cases at ultrasound was 7.6 +/- 2.0 weeks (mean +/- SD) with a range of 5.0-12.5 weeks. Reviewer 1 classified the extent of sonographic vesicular pattern as absent (10%), mild (63.3%), moderate (20%) and severe (6.7%). Reviewer 2 classified the cases as absent (10%), mild (53.3%), moderate (33.3%) and severe (3.3%). There was almost perfect agreement in categorizing the vesicular pattern between the reviewers (kappa = 0.866).

CONCLUSION

A mild sonographic vesicular pattern of CHM was common in the early first trimester.

In utero development of the fetal gall bladder in the Korean population

Objective

To provide reference ranges of the fetal gall bladder in the Korean population.

Materials and Methods

Fetal gall bladder development was evaluated in well-dated, non-anomalous fetuses in the Korean population between February and April 2003 and the visualization rate and reference values were determined from the obtained data.

Results

The visualization rate of the fetal gall bladder increased as gestation advanced to a plateau above 90%, which was maintained between 16 and 34 weeks. The measured parameters from the fetal gall bladder had a significant positive relationship with gestational age (p = 0.000 for all cases), and the correlation of length and area with the gestational age (r = 0.741 and r = 0.690, respectively) was better than the correlation of width, height, and volume with gestational age. The repeatability coefficients and coefficients of variation between the two operators were 5.56 mm and 12.9% for the length and 344.11 mm² and 33.52% for the area. The median length of the fetal gall bladder in the Korean population was not significantly different from the mean length of gall bladders in the Caucasian and African-American populations (p = 0.915).

Conclusion

We have provided reference values for the fetal gall bladder throughout the gestation period in the Korean population.

First-trimester screening for Down syndrome; the role of nasal bone assessment in the Korean population

OBJECTIVES

The aim of this study was to evaluate the role of nasal bone assessment in first-trimester screening for Down syndrome (DS) in the Korean population.

METHODS

From July 2004 to March 2006, we prospectively evaluated the fetal nasal bones at 11-14 weeks' gestation in the Korean population.

RESULTS

A successful evaluation was possible in 6490 of 6787 fetuses (95.6%). Absent, hypoechoic, and short nasal bones were seen in 4 (26.7%), 4 (26.7%), and 1 (6.7%) of 15 fetuses with DS, respectively, whereas in 5 (0.1%), 11 (0.2%), and 246 (3.8%) of 6456 normal fetuses. The incidence of absent and hypoechoic nasal bone showed significant differences between normal fetuses and fetuses with DS (P < 0.0005, both). Screening for DS using an absent or hypoechoic nasal bone resulted in a sensitivity of 53.3%, a specificity of 99.8%, a positive likelihood ratio of 215.2, and a negative likelihood ratio of 0.5.

CONCLUSION

Our study showed that nasal bone abnormality at 11-14 weeks of gestation had a high association with DS in the Korean population. This suggests that nasal bone assessment can be used to supplement the current first-trimester screening for DS in the Korean population.

Reference charts and equations of Korean fetal biometry

OBJECTIVE

To construct new reference charts and equations for fetal biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC) and femur diaphysis length (FDL) from Korean fetuses at 12-40 weeks.

METHOD

Prospective cross-sectional data obtained in one center for 5 years from a population of pregnant women undergoing ultrasound examination between the 12th and 40th week of gestation. Exclusion criteria comprised all maternal and fetal conditions possibly affecting fetal biometry. No fetuses were excluded on the basis of abnormal biometry. For each measurement, regression models were fitted to estimate both the mean and the standard deviation at each menstrual age.

RESULTS

Biometric measurements were obtained for 10 455 fetuses. New charts and reference equations are reported for BPD, HC, AC and FDL. Reference equations are cubic models.

CONCLUSION

We present new Korean reference charts and equations for fetal biometry. They can be easily used in obstetric ultrasound studies for the Korean population.

Three-vessel view of the fetal heart: In utero development of the great vessels

OBJECTIVES

The purpose of our study is to provide reference values for the great vessels obtained from images of the three-vessel view of the fetal heart, with an emphasis on the size discrepancy of the great vessels.

METHODS

From February 2003 to May 2003, the main pulmonary artery (MPA), ascending aorta (AA), and SVC were measured in well-dated, nonanomalous fetuses scanned at 14-38 weeks of gestation.

RESULTS

The size of each great vessel had a significant positive relationship with advance in gestation (P < 0.001); MPA (mm) = -2.76 + 0.34 x GA, ascending aorta (AA) (mm) = -1.73 + 0.26 x GA - 1.18E - 05 x GA(3), and SVC (mm) = 0.33 + 0.01 x GA(2) - 4.12E - 05 x GA(3). The AA/MPA ratio was significantly decreased with advance in gestation, while the SVC/AA ratio was significantly increased; AA/MPA ratio = -1.24 - 0.03 x GA + 3.88E - 04 x GA(2); P < 0.001, SVC/AA ratio = 0.63 - 5.43E - 03 x GA + 1.96E - 04 x GA(2); P < 0.001.

CONCLUSION

On the three-vessel view of the fetal heart, the interpretation of the size discrepancy of the great vessels needs to be adjusted according to fetal growth.