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OBJECTIVE: To compare the quality of various polychromatic and monochromatic images with or without using an iterative metal artifact reduction algorithm (iMAR) obtained from a dual-energy computed tomography (CT) to evaluate total knee arthroplasty. MATERIALS AND METHODS: We included 58 patients (28 male and 30 female; mean age [range], 71.4 [61-83] years) who underwent 74 knee examinations after total knee arthroplasty using dual-energy CT. CT image sets consisted of polychromatic image sets that linearly blended 80 kVp and tin-filtered 140 kVp using weighting factors of 0.4, 0, and -0.3, and monochromatic images at 130, 150, 170, and 190 keV. These image sets were obtained with and without applying iMAR, creating a total of 14 image sets. Two readers qualitatively ranked the image quality (1 [lowest quality] through 14 [highest quality]). Volumes of high- and low-density artifacts and contrast-to-noise ratios (CNRs) between the bone and fat tissue were quantitatively measured in a subset of 25 knees unaffected by metal artifacts. RESULTS: iMAR-applied, polychromatic images using weighting factors of -0.3 and 0.0 (P-0.3i and P0.0i, respectively) showed the highest image-quality rank scores (median of 14 for both by one reader and 13 and 14, respectively, by the other reader; p < 0.001). All iMAR-applied image series showed higher rank scores than the iMAR-unapplied ones. The smallest volumes of low-density artifacts were found in P-0.3i, P0.0i, and iMAR-applied monochromatic images at 130 keV. The smallest volumes of high-density artifacts were noted in P-0.3i. The CNRs were best in polychromatic images using a weighting factor of 0.4 with or without iMAR application, followed by polychromatic images using a weighting factor of 0.0 with or without iMAR application. CONCLUSION: Polychromatic images combined with iMAR application, P-0.3i and P0.0i, provided better image qualities and substantial metal artifact reduction compared with other image sets.

The aim of the study was to retrospectively evaluate the safety and accuracy of computed tomography (CT)-guided percutaneous transthoracic needle biopsy (PTNB) of lung lesions during quiet breathing.We investigated the diagnostic performance and complication rate of 585 procedures in 563 patients (357 men; mean age, 67.7 years), who underwent CT-guided PTNBs during quiet breathing, aided by a respiratory targeting technique from May 2017 to July 2019. Differences between the cases with and without respiratory targeting were analyzed. Logistic regression analyses were performed to examine the development of pneumothorax and hemoptysis.Percutaneous transthoracic needle biopsy samples were successfully obtained in 574 of 585 procedures (98.1%). Final diagnoses included: 410 malignant cases, 119 benign cases, and 45 indeterminate cases. The sensitivity, specificity, and accuracy of diagnosis were 94.4%, 100%, and 95.7%, respectively. Use of respiratory targeting was associated with younger age (P = 0.004), smaller lesion size (P0.001), peripheral location (P = 0.003), shorter distance from the diaphragm (P0.001), lower lobe location (P0.001), prone position (P = 0.004), and visible motion artifact (P0.001). Pneumothorax and hemoptysis rates were 22.9% and 7.9%, respectively. Upon multivariate analysis, emphysema (P = 0.002) was the only independent risk factor for pneumothorax, whereas distance from the pleura greater than 2 cm (P0.001), tissue sampling 3 times or more (P = 0.003), and a less experienced operator (P0.001) were risk factors for hemoptysis.Computed tomography-guided PTNB during quiet breathing with respiratory targeting yielded high diagnostic performance with a slightly higher rate of complications. Free-breathing PTNB can be applied in clinical practice, based on lesion location and risk factors for complications.

Background Tin filter-based spectral shaping has been used for low-dose and ultra-low-dose computed tomography (CT) in several body parts. However, studies of shoulder CT arthrography with spectral shaping are limited. Purpose To investigate image quality and radiation dose of shoulder CT arthrography with tin filter-based spectral shaping at 100 kV (Sn 100 kV) and 140 kV (Sn 140 kV) in comparison with the conventional protocol. Material and Methods Ninety-nine shoulder CT arthrographies with protocols of Sn 100 kV (n = 32), Sn 140 kV (n = 25), and conventional 120 kV (n = 42) were retrospectively evaluated. Qualitative image quality, CT attenuations of intra-articular contrast mixture and tissues, background noise, contrast-to-noise ratios (CNRs), and figures of merit were assessed. Radiation doses were compared. Results CT arthrographies with Sn 100 kV and Sn 140 kV yielded approximately 70% and 60% radiation dose reduction, respectively, compared with the conventional 120 kV ( P Conclusion Shoulder CT arthrography with Sn 100 kV substantially reduced radiation dose and image noise and maintained image contrast, compared with the conventional protocol.

Background Although time-of-flight magnetic resonance angiography (TOF-MRA) is widely used, it has limited usefulness for follow-up after stent-assisted coil embolization. Contrast-enhanced MRA (CE-MRA) and ultrashort echo time MRA have been suggested as alternative methods for visualization after this procedure. Purpose To compare efficacy and usefulness of pointwise encoding time reduction with radial acquisition (PETRA) sequence in subtraction-based MRA (qMRA), TOF-MRA, and CE-MRA during the follow-up after Neuroform Atlas stent-assisted coil embolization for intracranial aneurysms. Material and Methods This retrospective study included 23 patients with 24 aneurysms who underwent Neuroform Atlas stent-assisted coil embolization for intracranial aneurysms. All patients were evaluated with PETRA qMRA, TOF-MRA, and CE-MRA at the same follow-up session. The flow within stents, occlusion status, and presence of pseudo-stenosis were evaluated; inter-observer and intermodality agreements for the three methods were also graded. Results The mean score for flow visualization within the stents was significantly higher for PETRA qMRA and CE-MRA than for TOF-MRA (although no significant difference was found between PETRA qMRA and CE-MRA). Good inter-observer agreement was observed for each modality. PETRA qMRA and CE-MRA were more consistent with digital subtraction angiography (DSA) than TOF-MRA for aneurysm occlusion status. The intermodality agreement was better between PETRA qMRA and DSA, and between CE-MRA and DSA, than between DSA and TOF-MRA. Pseudo-stenosis was most frequently observed in TOF-MRA, followed by CE-MRA and PETRA qMRA. Conclusion PETRA qMRA is useful for evaluating the parent artery patency and occlusion status of aneurysms after Neuroform Atlas stent-assisted coil embolization.

According to the reports presented at the Fourth Asian Oceanian Radiology Forum (AORF) 2018, organized by the Korean Society of Radiology during the Korean Congress of Radiology in September 2018 in Seoul, there is an increasing demand for the Asian Oceanian Society of Radiology and its member societies for international education in radiology in the Asian Oceanian region. In AORF 2018, the national delegates of the Asian Oceanian radiological partner societies primarily discussed their societies' activities and current status of international education in radiology.

To compare the MR findings of septic and acute gouty arthritis of the knee joint.This retrospective study included patients who underwent knee MRI for septic or gouty arthritis at our hospital between October 2012 and October 2018. The MR findings were analyzed for the presence of bone marrow edema, soft tissue edema, abscess, pattern of synovial thickening (frondlike, lamellated, diffuse linear), maximum thickness of the synovium, and joint effusion volume. The gouty (No statistically significant differences were observed for each item. One patient in the gouty arthritis group and seven in the septic arthritis group had bone marrow edema. Soft tissue abscess formation was only observed in the septic group. The incidence of each synovial thickening pattern was as follows: 100% (diffuse linear) in the gouty arthritis group and 20% (frondlike), 50% (lamellated), and 30% (diffuse linear) in the septic arthritis group.Differentiation of gouty arthritis and septic arthritis based on imaging findings is difficult. However, lamellated synovial thickening patterns, bone marrow edema, and soft tissue abscess formation are more commonly observed in patients with septic arthritis than in those with gouty arthritis.급성 통풍성 관절염과 패혈성 관절염의 자기공명영상 소견 차이를 알아본다.2012년 10월부터 2018년 10월까지 패혈성 혹은 통풍성 관절염으로 확진된 자기공명영상을 촬영한 환자를 대상으로 연구하였다. 패혈성 관절염과 급성 통풍성 관절염의 자기공명영상 소견으로 골수부종, 연부조직 부종, 농양 형성 여부, 활액막 비후 양상(엽상체, 층판, 미만성 선형 모양), 활액막 최대 두께와 관절액 양을 평가하였다. 통풍성 관절염(5명)과 패혈성 관절염(10명)을 윌콕슨 순위합 검정과 피셔 정확 검정으로 비교하였다.자기공명영상으로 평가된 각 소견은 두 군 사이에 유의한 통계학적 차이는 보이지 않았다. 골수부종은 통풍성 관절염군에서 1건, 패혈성 관절염군에서 7건 관찰되었다. 연부조직 농양은 패혈성 관절염군에서만 관찰되었다. 활액막 비후양상은 통풍성 관절염군은 모두 미만성 선형 모양(100%), 패혈성 관절염군은 엽상체 모양(20%), 층판 모양(50%), 미만성 선형 모양(30%)으로 나타났다.통풍성 관절염과 패혈성 관절염은 자기공명영상 소견만으로 감별은 어려울 것으로 생각된다. 그러나 층판 모양 활액막 비후나 골수부종, 연부조직 농양의 경우 패혈성 관절염에서더 흔히 보였다.

To evaluate the diagnostic performance, image quality, artifacts, and radiation doses of virtual non-contrast (VNC) images, relative to true non-contrast (TNC) images, in patients with surgically clipped aneurysms. Seventy-six patients who underwent unenhanced computed tomography (CT) and dual-energy (DE)-CT angiography after surgical clipping of 85 intracranial aneurysms were included in the study. Diagnostic performances of VNC and TNC images were compared with respect to sensitivity, specificity, and positive and negative predictive values. The results of quantitative and qualitative analyses were compared between VNC and TNC images. Radiation doses were also compared between VNC and TNC images. Diagnostic performance of VNC images was lower than that of TNC images; however, addition of contrast-enhanced images improved diagnostic performance. Image noise and mean attenuation of VNC images were significantly higher than those of TNC images in the centrum semiovale, cerebellum, and pons. The quality of VNC images was excellent or sufficient (85.5% for observer 1, 85.5% for observer 2), and complete acceptance of VNC images was achieved in 64.5% for observer 1 and in 71.0% for observer 2; however, the addition of contrast-enhanced images increased the level of acceptance (92.0% for observer 1, 90.9% for observer 2). Clip artifacts were significantly lower in VNC images than in TNC images. CT dose index, dose-length product, and effective dose were significantly lower without TNC images. VNC images showed lower diagnostic performance and image quality, and higher image noise than TNC images; however, VNC images could reduce clip artifacts and radiation doses.

To evaluate the normal location of the peroneus longus tendon (PL) in the cuboid groove in various ankle–foot positions by ultrasonography in asymptomatic volunteers. Ultrasonographic assessment of the PL in the cuboid groove was performed in 20 feet of ten healthy volunteers. Each PL was examined in five ankle–foot positions (i.e., neutral, dorsiflexion, plantar-flexion, supination, and pronation). The PL location was qualitatively categorized as “inside” when the PL was entirely within the cuboid groove, as “overlying” when some part of the PL was perched on the cuboid tuberosity, and as “outside” when the PL was entirely on the cuboid tuberosity. For quantitative evaluation of the PL location, the distance between the PL and the cuboid groove was measured. The width of the cuboid groove was measured in the neutral position. The PL location did not significantly change with changes in the ankle–foot position. Qualitatively, an “overlying” PL was the most common type, regardless of the ankle–foot position. “Inside” PLs were found in only 35, 20, 30, 25, and 35% of feet in neutral, dorsiflexion, plantar-flexion, supination, and pronation positions, respectively. The quantitative PL location was also not significantly different among all ankle–foot positions and it was significantly negatively correlated with the cuboid groove width. In healthy volunteers, 65% or more of the PLs were partially or completely located outside of the cuboid groove, regardless of the ankle–foot position. The PL location relative to the cuboid groove was related to the cuboid groove width.

A gadolinium-based contrast is the preferred agent when differentiating acute neurological diseases. Since the renal route is the main pathway for excretion of gadolinium chelates, prolonged extracellular distribution of gadolinium has previously been reported in dialysis-dependent patients. Hence, gadolinium-based contrast agents are used cautiously in patients with known renal disease. Retention of gadolinium manifests as increased fluid-attenuated inversion recovery (FLAIR) signal intensity in the subarachnoid space, leading to diagnostic errors. Here, we describe a patient who presented to our emergency room with an acute cerebral infarction. Enhanced brain magnetic resonance imaging performed 2 days later revealed high signal intensity in the cerebrospinal fluid spaces on follow-up FLAIR images.

Persistent trigeminal artery (PTA) is a rare cerebrovascular variation of remnant fetal carotid-vertebrobasilar anastomoses. The PTA variant terminates in the cerebellar artery with no direct connection to the basilar artery. We present a rare case of a PTA variant that terminated directly into the ipsilateral posterior inferior cerebellar artery.

Background The distally extended muscle belly of the flexor digitorum (MB-FD) within the carpal tunnel has been suggested as a plausible cause for carpal tunnel syndrome (CTS) based on cadaveric studies. Purpose To evaluate whether MB-FD within the carpal tunnel is a risk factor for CTS by comparing asymptomatic volunteers and patients with CTS. Material and Methods Presence, length, and cross-sectional area of MB-FD within the carpal tunnel were evaluated in 63 wrists of 32 asymptomatic volunteers and 52 wrists of 33 patients with CTS using ultrasonography. Length of MB-FD within the carpal tunnel was measured as the distance between the distal end of MB-FD and the palmar margin of the distal radius longitudinally. On a transverse scan, the cross-sectional area of MB-FD at the proximal limit of the carpal tunnel was measured. Results MB-FD in the carpal tunnel was found in 39 (62%) asymptomatic volunteers and 35 (67%) patients with CTS ( P = 0.549). There was a female preponderancy of MB-FD within the carpal tunnel in asymptomatic volunteers ( P = 0.044), but not in patients. Length and cross-sectional area of MB-FD within the carpal tunnel were significantly greater in male-CTS patients than in male volunteers ( P = 0.022 and 0.012, respectively). These qualities were risk factors for CTS in men, though not in women. Conclusion The presence of distally extended MB-FD within the carpal tunnel was not a risk factor for CTS. In men, a longer and thicker MB-FD within the carpal tunnel increased the risk for CTS.

Metallic artifacts on MR imaging are typically induced by differences in magnetic susceptibility between the metallic implant and surrounding tissue. Conventional techniques for metal artifact reduction require MR machines with low field strength, shift in the frequency-encoding and phase-encoding directions according to the axis of metallic implant, increased receiver bandwidth and matrix, decreased slice thickness, and utilization of the short tau inversion recovery or Dixon method for fat-suppression. Slice-encoding for metal artifact correction and multi-acquisition variable-resonance image combination can dramatically reduce the number of metallic artifacts. However, these sequences have a considerably long acquisition time. Furthermore, the recently developed acceleration techniques including compressed sensing can solve this problem.

Purpose We evaluated the risk factors for progression to chronic complicated bronchopleural fistula (BPF) after pulmonary resection using follow-up CT. Materials and Methods We retrospectively reviewed 45 cases with BPF that had undergone pulmonary resection during 2010-2018. We compared the clinical and radiological characteristics of those with complicated BPF (n = 24) and those without complicated (sterilized) BPF (n = 21). The clinical and radiological risk factors for progression to chronic complicated BPF were examined by logistic regression analysis. Results The thickness of the pleural cavity wall (p = 0.022), the size of the pleural cavity (p = 0.029), and the size increase of BPF on follow-up (p = 0.012) were significantly different between the two groups. The risk factors for progression to chronic complicated BPF were age > 70 years (odds ratio, 6.43; 95% confidence interval, 1.2–33.7), the thickness of the cavity wall > 5 mm (odds ratio, 52.5; 95% confidence interval, 5.1–545.4), and an increase in the size of the pleural cavity on follow-up CT (odds ratio, 12.5; 95% confidence interval, 2.1–73.5), only in the univariate analysis. Conclusion The risk factors for progression to chronic complicated BPF can be evaluated using follow-up CT.

OBJECTIVES This study aimed to assess multiple factors influencing the outcomes of ultrasound (US)-guided fine-needle aspiration (FNA) of salivary gland lesions. METHODS From 2008 to 2013, a single radiologist performed US-guided FNA of salivary gland lesions in 243 patients. With the exclusion of pure cysts, poor image quality, and insufficient static image cases, 218 salivary gland lesions in 218 patients were included. The composition, size, location, and vascularity of the lesions were retrospectively investigated on the basis of sonographic findings by the same radiologist. The relationship between sampling adequacy and multiple factors was compared, and the diagnostic accuracy of US-guided FNA of salivary gland lesions was calculated by using the final diagnosis as a reference standard. RESULTS The sampling adequacy rate for US-guided FNA of the 218 salivary gland lesions was 96.8% (211 of 218). A significant difference was observed in the composition and vascularity of the lesions (P < .0001), whereas there was no significant difference in the patient age and sex, lesion size, lesion location, and needle size. The rate of inadequate sampling increased in predominantly cystic lesions compared with solid lesions as well as in low-vascularity lesions compared with high-vascularity lesions. Of the 218 lesions, 178 (81.7%) were ultimately diagnosed, and most were benign (162 of 178 [91.0%]). When 3 cases with indeterminate cytologic results were excluded, the sensitivity, specificity, positive and negative predictive values, and accuracy of US-guided FNA of salivary gland lesions were 64.3%, 98.8%, 81.8%, 97.0%, and 96.0%, respectively. CONCLUSIONS When using US-guided FNA to diagnose salivary gland lesions, sampling adequacy depends on the composition or vascularity of the lesions.

Purpose No previous study using follow-up ultrasonography for evaluating the factors associated with the successful regression of congenital muscular torticollis in young infants has been published. This study aimed to assess clinical factors and sonographic features potentially influencing regression in patients with congenital muscular torticollis. Methods From January 2010 to December 2012, 80 infants underwent neck ultrasonography because of clinical suspicion of congenital muscular torticollis. We statistically analysed the correlation between complete resolution and clinicosonographic findings when complete resolution was defined as no visible lesion on follow-up ultrasonography. Results Of the 80 infants, 61 had congenital muscular torticollis and all were followed up by ultrasonography: 1) 34 underwent physiotherapy, and 27 of them (79.4%) revealed complete resolution in follow-up; 2) 27 did not undergo physiotherapy, and 15 of them (55.6%) showed complete resolution. A statistically significant correlation was found between physiotherapy and complete resolution, but not between complete resolution and patient sex; size, volume, and echogenicity of the lesion; and thickness ratio. Conclusions Physiotherapy was the only factor influencing complete resolution in young infants with congenital muscular torticollis.

Background Acute ischemic stroke (AIS) more frequently develops in patients with intracranial vertebral artery dissection (VAD) than extracranial VAD, and is associated with possible poor clinical outcomes. The aim of this study is to compare high-resolution magnetic resonance imaging (HR-MRI) findings and clinical features of VAD with and without AIS. Methods Twenty-nine lesions from 27 patients (15 male and 12 female patients; age range = 28–73 years) who underwent diffusion MRI and 3T HR-MRI within seven days were included. We classified VAD according to the presence of AIS lesions on diffusion MRI. Clinical features and HR-MRI findings (angiographic patterns, presence of double lumen sign, dissecting flap, posterior inferior cerebellar artery involvement, remodeling index, length of affected vessels, T1-signal intensity, area of intramural hematoma, and grades and patterns of vessel wall enhancement) were evaluated. Results Thirteen VADs with AIS and 16 without AIS were included. There were no significant differences in the clinical parameters (sex, age, risk factors, symptoms). More VADs with AIS presented as a steno-occlusive pattern than VADs without AIS. More VADs without AIS presented with aneurysmal dilation, larger mean remodeling index and longer mean length than VADs with AIS. Presence of intramural hematoma, T1-iso-signal intensity of intramural hematoma and contrast enhancement were significantly more common in VADs with AIS than without AIS. Conclusions Our study showed some differences in HR-MRI comparing intracranial VAD patients with and without AIS. Differing findings may facilitate a better understanding of intracranial VAD and risk assessment of AIS in these patients.

The aim of this study was to compare the ultrasonographic findings of femoral puncture sites and the complications of Perclose ProGlide® and FemoSeal™ after neurointerventional procedures. In this prospective, single-center study, we randomly assigned 155 femoral puncture sites to treatment with Perclose ProGlide® or FemoSeal™. We hypothesized that the two different types of VCD cause different vascular changes. Ultrasonography of the femoral puncture sites was performed 24 h after the procedure and at an outpatient visit after 6 months. The intima–media thickness (IMT), vessel diameter, and minimal luminal diameter of the common femoral artery were measured; the perivascular soft tissue change and absorption of the hemostatic material were observed. The device failure rate and vascular complications associated with each device were also evaluated. Follow-up ultrasonography was performed at a median follow-up time of 187.0 days (range 147–240 days) after the initial ultrasonography. The IMT on follow-up ultrasonography was significantly higher in patients who received FemoSeal™ (P = 0.0000). Intimal hyperplasia and partial absorption of the hemostatic material were significantly more frequent in patients who received FemoSeal™. The vessel diameters on initial and follow-up ultrasonography were not significantly different, but the minimal diameter on follow-up ultrasonography was significantly lower in patients who received FemoSeal™. Device failure and pseudoaneurysms occurred at 9 and 3 puncture sites in patients who received Perclose ProGlide®, respectively. Intimal hyperplasia was more frequently observed in patients who received FemoSeal™. However, more device failures and pseudoaneurysms occurred in patients who received Perclose ProGlide®. Step 2 (level 2).

OBJECTIVE. The purpose of this study was to evaluate the prevalence, radiologic characteristics, and accuracy of diagnosing delaminated tears at the supraspinatus tendon-infraspinatus tendon (SST-IST) on indirect MR arthrography. MATERIALS AND METHODS. Of 531 consecutive shoulders that underwent indirect MR arthrography, 231 shoulders with tears at the SST-IST were included. On the MR images, delaminated tears at the SST-IST, defined as intratendinous horizontal splitting between the articular and bursal layers of the SST-IST with or without different degrees of retraction between the two layers, were identified and classified into six types. Other radiologic findings of the SST-IST, such as the presence of intramuscular cysts, were evaluated. We used video records of 127 arthroscopic surgeries to determine the diagnostic accuracy of indirect MRI for the detection of the delaminated tears at the SST-IST. RESULTS. On MRI, 56% (129/231) of shoulders with SST-IST tears had delaminated tears. Articular-delaminated full-thickness tears (n = 58) and articular-delaminated partial-thickness tears (n = 64) were the most common types. Approximately 82% (36/44) of articular-delaminated full-thickness tears occurring at the SST were combined with articular-delaminated partial-thickness tears at the IST. SST-IST footprint tears and intramuscular cysts were significantly more common in the shoulders with delaminated tears. The sensitivity and specificity of indirect MR arthrography for detection of delaminated tears were 92% and 94%, respectively. CONCLUSION. On indirect MR arthrography, approximately half of the shoulders with SST-IST tears had delaminated tears. The diagnostic accuracy of indirect MR arthrography for detection of delaminated tears was high.

BackgroundThe rotator cable is an important structure providing stress shield to the rotator cuff, similar to the mechanism of suspension bridge.PurposeTo evaluate the visibility and appearance of the rotator cable in various conditions of the rotator cuff, using indirect magnetic resonance (MR) arthrography.Material and MethodsIndirect MR arthrography images from 27 patients (age range, 20–63 years) with normal rotator cuffs, and 47 (age range, 20–73 years) with tendinosis, 32 (age range, 49–71 years) with partial-thickness tears, and 55 (age range, 44–75 years) with full-thickness tears in the supraspinatus and infraspinatus tendons (SST-ISTs) were included in this study. In these various rotator cuff conditions, the visibility and appearance (thickness and width) of the rotator cable and the relationships between the rotator cable appearance, rotator cuff tear size, rotator cuff thickness, and patient’s age were assessed.ResultsOn the sagittal MR images, all rotator cables were visible in the normal rotator cuffs and tendinosis/partial-thickness tears of SST-ISTs. In the order of normal cuff, tendinosis, partial-thickness tear, and full-thickness tear of SST-ISTs, the rotator cable tended to become thicker (1.07, 1.27, 1.32, and 1.59 mm, respectively) and narrower (12.1, 10.68, 10.90, and 8.55 mm, respectively). The thickness of the rotator cable was significantly positively correlated with the rotator cuff thickness in the normal rotator cuffs (coefficient, 0.49; P = 0.010) and tendinosis of SST-ISTs (coefficient, 0.53; P ConclusionOn sagittal plane of indirect MR arthrography, most rotator cables were visible. The appearance of the rotator cable changed according to the rotator cuff condition.

Objectives The purpose of this study was to evaluate characteristic features of juvenile fibroadenoma of the breast on sonography. Methods Our study included 34 juvenile fibroadenomas confirmed by surgical biopsy or sonographically guided 8-gauge vacuum-assisted biopsy in 23 patients (age range, 15-47 years; mean age, 25 years). Sonographic findings of the lesions were analyzed retrospectively by 2 radiologists in consensus according to the American College of Radiology Breast Imaging Reporting and Data System (BI-RADS) lexicon. The BI-RADS final assessment category was also established. Results On sonography, all fibroadenomas presented as masses. The mean size was 30 mm. Regarding shape, there were 29 oval, 2 round, and 3 irregular masses. The margins were circumscribed in 24, indistinct in 5, microlobulated in 4, and angular in 1. Regarding echogenicity, 16 masses were hypoechoic, 16 isoechoic, and 2 complex echoic. Posterior acoustic characteristics included posterior acoustic enhancement in 22 masses (65%), posterior shadowing in 1, and no posterior acoustic features in 9; this information was not available in 2. The lesion boundary presented as an abrupt interface in 32 and an echogenic halo in 2. The orientation was parallel in 32 and nonparallel in 2. Calcifications were present in 3 cases and absent in 31. On color Doppler sonography, the masses were usually hypervascular with vessel counts of 5 or more (87%). The BI-RADS final assessment categories were 3 in 24 and 4a in 10. Conclusions The dominant sonographic presentation of juvenile fibroadenoma is a circumscribed oval hypoechoic or isoechoic mass, which resembles that of simple fibroadenoma. Juvenile fibroadenomas frequently show posterior acoustic enhancement and hypervascularity on color Doppler sonography.

Purpose The purpose was to evaluate the clinical value of PETRA sequence for the diagnosis of internal derangement of the knee. Materials and methods The major structures of the knee in 34 patients were evaluated and compared among conventional MRI findings, PETRA images, and arthroscopic findings. Results The specificities of PETRA with 2D FSE sequence were higher for meniscal lesions than those obtained when using 2D FSE alone. Conclusion Using PETRA images along with conventional 2D FSE images can increase the accuracy of assessing internal derangements of the knee and, specifically, meniscal lesions.

The purpose of this study is to evaluate the frequency and MRI characteristics of multibanded anterior talofibular ligaments in normal ankles and to characterize the tear types of multibanded anterior talofibular ligaments in sprained ankles using a 3D isotropic proton density (PD)-weighted fast spin-echo (FSE) MRI sequence.In the first session, 3D PD-weighted FSE MRI of 33 ankles was obtained from 20 asymptomatic volunteers. The number of bands in the anterior talofibular ligaments, the locations of the anterior talofibular ligaments on orthogonal planes of the 3D PD-weighted FSE images, and the signal intensity, depth, and width of each band on their multiplanar reformatted images parallel to the orientation of each band of the anterior talofibular ligament were evaluated by two readers. In the second session, 3D PD-weighted FSE MRI of 51 sprained ankles was evaluated by two readers for determining the number of bands in the anterior talofibular ligaments and the presence of tears in each band.In the first session, three anterior talofibular ligaments were single banded, 27 were double banded, and three were triple banded. In double-banded anterior talofibular ligaments, the superior band was about two times wider and thicker than the inferior band. The depth, width, and location of single-banded anterior talofibular ligaments and the superior band of double-banded anterior talofibular ligaments were not statistically significantly different. In the second session, the most common type of injury in double-banded anterior talofibular ligaments was a two-band tear.In an evaluation using the 3D PD-weighted FSE sequence, most anterior talofibular ligaments consisted of two bands, and tears in both bands were the most common type of injury in double-banded anterior talofibular ligaments.

Objective To investigate the image quality, radiation dose, and intermodality agreement of cervical spine CT using spectral shaping at 140 kVp by a tin filter (Sn140-kVp) in comparison with those of conventional CT at 120 kVp. Materials and Methods Patients who had undergone cervical spine CT with Sn140-kVp (n = 58) and conventional 120 kVp (n = 49) were included. Qualitative image quality was analyzed using a 5-point Likert scale. Quantitative image quality was assessed by measuring the noise and attenuation within the central spinal canals at C3/4, C6/7, and C7/T1 levels. Radiation doses received by patients were estimated. The intermodality agreement for disc morphology between CT and MRI was assessed at C3/4, C5/6, C6/7, and C7/T1 levels in 75 patients who had undergone cervical spine MRI as well as CT. Results Qualitative image quality was significantly superior in Sn140-kVp scans than in the conventional scans (p < 0.001). At C7/T1 level, the noise was significantly lower and the decrease in attenuation was significantly less in Sn140-kVp scans, than in the conventional scans (p < 0.001). Radiation doses were significantly reduced in Sn140-kVp scans by 50% (effective dose: 1.0 ± 0.1 mSv vs. 2.0 ± 0.4 mSv; p < 0.001). Intermodality agreement in the lower cervical spine region tended to be better in Sn140-kVp acquisitions than in the conventional acquisitions. Conclusion Cervical spine CT using Sn140-kVp improves image quality of the lower cervical region without increasing the radiation dose. Thus, this protocol can be helpful to overcome the artifacts in the lower cervical spine CT images.

Purpose Chronic inflammatory condition such as metallic implants insertion state has relevance to develop diffuse large B-cell lymphoma (DLBCL). The purpose of this study is to introduce the imaging features of the metallic implants associated lymphoma. Materials and Methods In 2016 September, a 58 years-old male underwent high tibial osteotomy at right leg after took a knee magnetic resonance image (MRI). After 15 months later, he underwent hardware removal operation. 2 weeks later after operation, he complained right leg pain and swelling. He was hospitalized and radiologic studies including ultrasound (US) and MRI were performed. Soft tissue mass in right popliteal fossa was seen and US-guided biopsy was done to confirm the mass. Results MRI which was taken after hardware removal, showed iso to slightly low signal intensity on T1 weighted image(WI), high signal intensity on T2WI with diffuse marrow involvement and heterogeneous patchy enhancement in right proximal tibia. Also extensive extraosseous soft tissue component was seen, with relatively preserved trabecular pattern in proximal tibia. This intraosseous and extraosseous lesions were not seen in previous MRI which taken before high tibial osteotomy. On US image, it was showed heterogeneous hypoechoic and hypervascular lesion in popliteal fossa of left lower leg. US guided biopsy was done on extraosseous soft tissue mass in left popliteal fossa. It was histologically confirmed as DLBCL. Conclusion Hypoechoic and hypervascular disproportionally large extraosseous soft tissue mass without prominent bone destruction is preferential finding of bone lymphoma. Lymphoma should be considered above all, when these findings were seen in patient who has metallic implant.

OBJECTIVE To investigate the relationships of T₂*-corrected 6-echo Dixon volumetric interpolated breath-hold examination (VIBE) imaging-based fat fraction (FF) and R₂* values with bone mineral density (BMD); determine their associations with sex, age, and menopause; and evaluate the diagnostic performance of the FF and R₂* for predicting osteopenia and osteoporosis. MATERIALS AND METHODS This study included 153 subjects who had undergone magnetic resonance (MR) imaging, including MR spectroscopy (MRS) and T₂*-corrected 6-echo Dixon VIBE imaging. The FF and R₂* were measured at the L4 vertebra. The male and female groups were divided into two subgroups according to age or menopause. Lin's concordance and Pearson's correlation coefficients, Bland-Altman 95% limits of agreement, and the area under the curve (AUC) were calculated. RESULTS The correlation between the spectroscopic and 6-echo Dixon VIBE imaging-based FF values was statistically significant for both readers (pc = 0.940 [reader 1], 0.908 [reader 2]; both p < 0.001). A small measurement bias was observed for the MRS-based FF for both readers (mean difference = -0.3% [reader 1], 0.1% [reader 2]). We found a moderate negative correlation between BMD and the FF (r = -0.411 [reader 1], -0.436 [reader 2]; both p < 0.001) with younger men and premenopausal women showing higher correlations. R₂* and BMD were more significantly correlated in women than in men, and the highest correlation was observed in postmenopausal women (r = 0.626 [reader 1], 0.644 [reader 2]; both p < 0.001). For predicting osteopenia and osteoporosis, the FF had a higher AUC in men and R₂* had a higher AUC in women. The AUC for predicting osteoporosis was highest with a combination of the FF and R₂* in postmenopausal women (AUC = 0.872 [reader 1], 0.867 [reader 2]; both p < 0.001). CONCLUSION The FF and R₂* measured using T₂*-corrected 6-echo Dixon VIBE imaging can serve as predictors of osteopenia and osteoporosis. R₂* might be useful for predicting osteoporosis, especially in postmenopausal women.

Objectives Unlike the preoperative findings in patients with papillary thyroid carcinoma, the postoperative sonographic features of cervical lymph nodes have not been established. This study aimed to assess the sonographic features of metastatic lymph nodes after thyroidectomy for papillary thyroid carcinoma. Methods The study population consisted of 104 consecutively registered patients who had undergone thyroidectomy for papillary thyroid carcinoma and underwent sonographically guided fine-needle aspiration of lymph nodes in the neck. The sonographic features of each lymph node were retrospectively evaluated by a single radiologist. The confirmation methods for the 115 lymph nodes included surgery (n = 35), measurement of thyroglobulin levels in the aspirates (n = 2), malignant cytologic analysis (n = 10), and benign cytologic analysis with sonographic follow-up over 12 months (n = 68). We determined the diagnostic indices of individual sonographic features for differentiating between metastatic and benign lymph nodes by comparing these features with the final diagnoses. Results Of the 104 patients, 67 underwent at least 1 cycle of radioisotope therapy after thyroidectomy. The malignancy rate for the lymph nodes was 42.6% (49 of 115). A significant relationship was found between malignancy and the presence of an intranodal cystic component, intranodal microcalcifications, diffusely increased echogenicity, a microlobulated margin, a round shape, loss of echogenic hila, and mixed or central vascularity on color Doppler sonography (P Conclusions The sonographic features of metastatic cervical lymph nodes in postoperative patients with papillary thyroid carcinoma were similar to those in preoperative patients.

Lateral ankle pain is common with overuse and sports-related injuries and may cause considerable morbidity. The differential diagnosis of lateral ankle pain is extensive. Disorders of the peroneal tendons should be an important consideration during interpretation of a routine ankle magnetic resonance imaging (MRI) or ultrasound (US). This article presents a review of the common causes of peroneal tendon pathology with particular reference to anatomy, US, and MRI features. The importance of dynamic evaluation with ultrasound is also emphasized.

The objective of this study was to prospectively evaluate whether intraarticular anesthesia can reduce pain after MR or CT arthrography of the shoulder.This study included 120 patients who underwent CT or MR arthrography of the shoulder. The patients were randomized into two groups: the study group (n = 60), each administered an intraarticular injection of the contrast agent mixed with a local anesthetic (2% mepivacaine); and the control group (n = 60), each injected with the contrast agent only. Each patient's pain level was assessed at five phases-baseline and immediately, 2 hours, 1 day, and 2 days after injection-by using a visual analog scale or a verbal rating scale. The net pain score at each phase was also calculated. The pain course and net pain score were compared between study and control groups by repeated-measures analysis of variance. After the patients were divided into subgroups according to patient- or procedure-related factors, the efficacy of the intraarticular local anesthetic in each subgroup was evaluated.The pain course showed a quadratic trend and was not significantly different between study and control groups. The net pain score also was not significantly different between the two groups. No subgroup showed a significantly different efficacy of the intraarticular local anesthetic between the two groups.Intraarticular local anesthesia did not reduce arthrography-related pain.

This study aimed to assess the malignancy rate of solid and isoechoic thyroid nodules without malignant sonographic features (SITNs) and to compare the malignant and benign SITNs according to nodule size, shape and color Doppler pattern. Of 382 SITNs with the largest diameter ≥10 mm, nodule size, nodule shape (i.e. spherical vs. ovoid) and color Doppler pattern (i.e. scant, peripheral, central, and mixed type) of each nodule were retrospectively evaluated. A total of 114 SITNs were histopathologically confirmed by surgery (called surgical SITN) and the malignancy rate of surgical SITNs was 8.8% (10/114). There was no statistical association between the incidence of malignancy of SITNs and nodule size but the malignancy rate of spherical SITNs was higher than that of ovoid SITNs. A significant relationship between peripheral vascularity of SITNs and benignity was found but the other vascularity patterns showed no significant association with malignancy or benignity of SITNs.

Background To date, appropriate management for Bethesda IV thyroid nodules is controversial, and no specific features of follicular neoplasm and nodular hyperplasia on ultrasonography, computed tomography (CT), or other imaging modalities have been reported. This study aimed to compare CT features of follicular neoplasm and nodular hyperplasia and to determine the specific CT features that could be used to distinguish follicular neoplasm from nodular hyperplasia. Methods In 122 patients who underwent preoperative CT of the neck and thyroid surgery, 59 follicular neoplasms and 65 nodular hyperplasias were included. In each case, non-enhanced and contrast-enhanced CT images were obtained, and a single radiologist retrospectively analyzed CT images, including degree and pattern of attenuation, nodular configuration, margin, shape, pattern of calcification, degree and pattern of nodular enhancement, and CT halo sign. A univariate and multivariate logistic regression analyses were used to evaluate the predictive power of each variable and CT features with a high predictive power, respectively. Results According to the univariate analysis, iso-attenuation, intraglandular configuration, smooth margin, ovoid shape, decreased enhancement, and absence of CT halo sign were more frequently observed in nodular hyperplasia (p

Pancreatitis, panniculitis, and polyarthritis (PPP) syndrome is extremely rare and presents as a triad of the three diseases. The patient usually presents with mild or absent abdominal symptoms. Here, we report on a case of a 66-year-old male who presented with pain and swelling in both legs and mild abdominal pain. He was diagnosed with acute pancreatitis by pancreatic enzyme analysis and abdominal computed tomography (CT) and with skin lesions of panniculitis through a biopsy. Magnetic resonance imaging (MRI) revealed multifocal intraosseous fat necrosis and arthritis involving both the feet and the knees. Therefore, we report a case of PPP syndrome with intraosseous fat necrosis involving both the feet and the knees.

Various types of tumors can affect the subungual space, including benign solid tumors (glomus tumor, subungual exostosis, soft-tissue chondroma, keratoacanthoma, hemangioma, lobular capillary hemangioma), benign cystic lesions (epidermal and mucoid cysts), and malignant tumors (squamous cell carcinoma, malignant melanoma). Imaging plays an important role in the detection and differentiation of subungual tumors because of their small size, nonspecific clinical manifestations, and functional significance. Ultrasonography (US)-in particular, high-resolution US with color Doppler studies-provides useful information regarding tumor size, location, shape, and internal characteristics (cystic, solid, or mixed), but it is limited in the further characterization of tissue. Magnetic resonance (MR) imaging has an important role in categorizing tumors according to their anatomic location, pathologic origin, and signal characteristics. There is some overlap between the US and MR imaging features of subungual tumors; however, certain features can allow accurate diagnosis and expedite management when correlated with clinical and pathologic findings.

Objective The purpose of this study was to describe the ultrasonographic findings of angioleiomyoma based on pathological subtypes. Materials and methods Thirty-nine patients with subcutaneous angioleiomyomas in the extremities were retrospectively reviewed by two radiologists and a pathologist. Sonographic images were analyzed to evaluate each tumor's anatomic location, size, shape, margin, heterogeneity, echogenicity, associated findings, and vascularity. Results Angioleiomyomas were divided into 3 subtypes: capillary (n = 16), venous (n = 22), and cavernous (n = 1). The one cavernous angioleiomyoma was a hypoechoic mass with rich vascularity. Hypoechogenicity was more frequently observed for venous tumors (77.3%) than for capillary tumors (43.8%), and isoechogenicity was more frequently observed for capillary tumors (56.2%) than for venous tumors (22.7%). Moderate vascularity was more frequently observed for venous tumors (59.1%) than for capillary tumors (12.5%), and little vascularity was more frequently observed for capillary tumors (62.5%) than for venous tumors (13.6%). The aforementioned findings including echogenicity (p = 0.034) and vascularity (p = 0.003) were statistically significant. Conclusion Awareness of sonographic findings of angioleiomyomas based on pathologic subtypes could be helpful for diagnosing angioleiomyoma and could increase diagnostic accuracy for superficial soft-tissue masses in our practice.

Objective: The aim of this study was to determine the efficacy of the use of an ultrasound-guided fine-needle aspiration biopsy (US-FNAB) to diagnose thyroid nodules smaller than 5 mm in the maximum diameter and to evaluate pathological findings of small thyroid malignancies. Materials and Methods: From May 2007 to April 2008, we evaluated the findings of US-FNABs of small thyroid nodules less than 5 mm in the maximum diameter. The cytopathological findings were retrospectively reviewed and the diagnostic performance of the use of an US-FNAB was examined in all patients. Results: Of 201 small thyroid nodules in 180 patients, there were 162 adequate specimens (81%). Among 180 patients, 75 patients underwent thyroid surgery and 50 malignant and 33 benign nodules were identified based on a pathological examination. All small malignant thyroid nodules were identified as papillary thyroid microcarcinomas (PTMCs). There were 34 (55%) true positive, 0 (0%) false positive, 23 (37%) true negative and five (8%) false negative results for malignancy after performing a first US-FNAB in 62 surgically confirmed nodules. The sensitivity (87%), specificity (100%), positive predictive value (100%), negative predictive value (82%), accuracy (92%), false positive rate (0%) and false negative rate (8%) for an US-FNAB were determined. In 23 patients with a primary PTMC, capsular invasion (9%, 2 of 23), a perithyroidal lymph node metastasis (30%, 7 of 23), the rate of multifocality (9%, 2 of 23) and bilaterality (4%, 1 of 23) were also determined. Conclusion: An US-FNAB of thyroid nodules smaller than 5 mm in the maximum diameter is an effective diagnostic procedure.

The purpose of this study was to analyze statistically significant diagnostic factors for pilomatricoma on the basis of ultrasonographic features. Sonographic images were retrospectively reviewed from 44 pilomatricomas, and from 43 control subjects with other subcutaneous tumors. Two radiologists determined the tumoral shape, margin, echotexture, echogenicity, posterior shadowing, posterior enhancement, hypoechoic rim, internal calcification, and vascularity. The reliable diagnostic factors for pilomatricoma were hypoechogenicity (P

To describe grayscale and color Doppler ultrasound features of subcutaneous intravascular papillary endothelial hyperplasia (IPEH). The ultrasound appearances of ten histologically proven subcutaneous IPEH in ten patients (age range, 15–69 years; mean age, 38.2 years; six females, four males) were reviewed retrospectively by two musculoskeletal radiologists. Color Doppler examination and surgical excision were performed in all cases. The correlations between the ultrasound and pathological features of the lesions were done. All ten cases were pathologically diagnosed as pure forms of IPEH. The mean size of the lesions was 1.3 cm. The margins of the lesions were circumscribed in seven of ten patients. Three had lobular margins. The distinct internal septum-like structures were seen in seven of ten cases (70 %). The vascularity was rich in three (30 %), moderate in four (40 %), and little in three (30 %) of the ten cases. The most common vascular pattern was one or more vessels peripherally or both peripherally and centrally located in the lesion. The detectable origin vessel was noted in four of ten cases (40 %). Although sonographic features of subcutaneous IPEH are non-specific, they should be included in the differential diagnosis of a small, well-defined, oval or elliptical, heterogeneous, hypoechoic soft tissue mass, showing a vascular pattern of one or more vessels in the lesion and variable vascularity. The presence of the internal septum-like structures and detectable origin vessel may be help to distinguish the lesion from the other soft tissue masses.

Fibromatosis refers to an extra-abdominal desmoid tumor or aggressive fibromatosis. Breast fibromatosis can develop in association with the capsule around a breast implant, although reports of cases of fibromatosis associated with breast implants are rare. As the demand for breast augmentation has increased, it is important to understand the diseases associated with breast implants. In the present report, we describe a case of breast fibromatosis that developed adjacent to a breast implant and demonstrated a relatively well-defined border even though it invaded the surrounding structures. We also explore the specific imaging features for diagnosing breast fibromatosis in association with implants by reviewing previous literature.

There are various causes of calf pain. The differential diagnoses affecting the lower leg include cystic lesions, trauma-related lesions, infection or inflammation, vascular lesions, neoplasms, and miscellaneous entities. Ultrasound (US) provide detailed anatomical information of the calf structures, and it offers the ability to confirm, other calf abnormalities, particularly when deep vein thrombosis (DVT) is ruled out. The purpose of this article is to review the causes of a painful calf presenting as DVT and incidental findings found as part of the work-up of DVT, and to provide a broad overview of US findings and clinical features of these pathologies.

To describe ultrasound findings of Kimura’s disease arising in the upper extremities. Five patients with Kimura’s disease confirmed by surgical resection were retrospectively reviewed by two musculoskeletal radiologists and a pathologist. All six lesions involved the epitrochlear area and appeared as partially (n = 5) or poorly (n = 1) marginated subcutaneous masses with the presence of curvilinear hyperechoic bands intermingled within the hypoechoic components by US. Moderate (n = 4) to severe (n = 2) vascular signals were observed in some proportion of the hyperechoic bands by color Doppler US. The associated findings were the increased echogenicity of surrounding subcutaneous fat (n = 6) and adjacent lymphadenopathy (n = 4). Microscopic examination showed proliferation of lymphoid follicles with prominent germinal centers and intervening fibrosis. In this study, Kimura’s disease arising in the upper extremities showed a partially defined hypoechoic subcutaneous mass with internal hyperechoic bands and moderate-to-severe vascularities, increased echogenicity of the surrounding subcutaneous fat and adjacent lymphadenopathy on US. Thus, when these US features are observed in the typical epitrochlear region of an Asian individual, especially if accompanied by peripheral eosinophilia, Kimura’s disease should be considered as a possible diagnosis.

Objective To evaluate retrospectively whether symptomatic acromioclavicular joints can be differentiated from asymptomatic acromioclavicular joints on 3-T MR imaging. Methods This study included 146 patients who underwent physical examination of acromioclavicular joints and 3-T MR imaging of the shoulder. Among them, 67 patients showing positive results on physical examination were assigned to the symptomatic group, whereas 79 showing negative results were assigned to the asymptomatic group. The following MR findings were compared between the symptomatic and asymptomatic groups: presence of osteophytes, articular surface irregularity, subchondral cysts, acromioclavicular joint fluid, subacromial fluid, subacromial bony spurs, joint capsular distension, bone edema, intraarticular enhancement, periarticular enhancement, superior and inferior joint capsular distension degree, and joint capsular thickness. The patients were subsequently divided into groups based on age (younger, older) and the method of MR arthrography (direct MR arthrography, indirect MR arthrography), and all the MR findings in each subgroup were reanalyzed. The meaningful cutoff value of each significant continuous variable was calculated using receiver operating characteristic analysis. Results The degree of superior capsular distension was the only significant MR finding of symptomatic acromioclavicular joints and its meaningful cutoff value was 2.1 mm. After subgroup analyses, this variable was significant in the older age group and indirect MR arthrography group. Conclusion On 3-T MR imaging, the degree of superior joint capsular distension might be a predictable MR finding in the diagnosis of symptomatic acromioclavicular joints.

We report four patients who presented with a severe form of metaphyseal chondromatosis in association with D-2-hydroxyglutaric aciduria (D-2-HGA). All patients showed splaying columns of irregular ossification defects with bulbous metaphyses of the long tubular bones, as well as remarkable involvement of the short tubular and flat bones. The vertebral bodies revealed platyspondyly with irregular, stippled endplates. D-2-HGA has been described as a neurometabolic disorder manifesting a broad range of impairment in mental and motor development. Although hydroxyglutaric acid was excreted in high amounts in the urine of all four patients described herein, no significant neurologic abnormalities were evident. This unusual combination of characteristic skeletal and metabolic abnormalities has rarely been reported. Thus, our report will facilitate the recognition of this distinctive entity, and we suggest that a urine organic acid screening be obtained in patients who present with generalized enchondromatosis.

To describe magnetic resonance imaging (MRI) and ultrasound (US) findings of intravascular papillary endothelial hyperplasia (IPEH) arising in extremities.Six patients with IPEH confirmed by surgical resection were reviewed retrospectively. Before resection, 3 patients underwent both MRI and US and 3 patients underwent only MRI. Two radiologists retrospectively reviewed MR/US imaging results and correlated them with pathological features.The 6 IPEHs were diagnosed as 4 mixed forms and 2 pure forms. The pre-existing pathology of four mixed forms was intramuscular or intermuscular hemangioma. By MRI, the mixed form of IPEH (n = 4) revealed iso- to slightly high signal intensity containing nodule-like foci of high signal intensity on T1-weighted images (T1WI) and high signal intensity-containing nodule-like foci of low signal intensity on T2-weighted images (T2WI). The pure form of IPEH (n = 2) showed homogeneous iso- signal intensity on T1WI and high and low signal intensity containing nodule-like foci of low signal intensity on T2WI. On gadolinium-enhanced fat-suppressed T1WI, 50% of cases (n = 3: mixed forms) revealed peripheral, septal, and central enhancement. The other IPEHs (n = 3: 1 mixed and 2 pure forms) showed peripheral and septal enhancement or only peripheral enhancement. By US, two mixed forms of IPEH showed well-defined hypoechoic masses containing hyperechoic septa and central portion with vascularities. One pure form of IPEH was a homogeneous hypoechoic mass with septal and peripheral vascularities on color Doppler imaging. The foci of high signal intensity on T1WI, foci of low signal intensity on T2WI, and non-enhancing portions on MRI and the hypoechoic portion on US were histopathologically correlated with thrombi and the peripheral/septal or central enhancing areas on MRI, hyperechoic septa and the central portion on US, and septal/central or peripheral vascularities on color Doppler imaging corresponded to hypertrophic papillary epithelium and a fibrovascular core.Even though imaging findings of the pure form of IPEH are rather nonspecific, the mixed form of IPEH should be considered a possible diagnosis when a well-defined mass with T2 hyperintense signal containing nodule-like foci of low signal intensity, T1 iso- to slightly hyperintense signal containing nodule-like foci of high signal intensity, and peripheral/septal or central enhancement on MRI is seen in extremities, along with the US finding of a hypoechoic mass containing hyperechoic septa with vascularities.