Differentiating Uterine Sarcoma From Atypical Leiomyoma on Preoperative Magnetic Resonance Imaging Using Logistic Regression Classifier: Added Value of Diffusion-Weighted Imaging-Based Quantitative Parameters.

OBJECTIVE: To evaluate the added value of diffusion-weighted imaging (DWI)-based quantitative parameters to distinguish uterine sarcomas from atypical leiomyomas on preoperative magnetic resonance imaging (MRI). MATERIALS AND METHODS: A total of 138 patients (age, 43.7 ± 10.3 years) with uterine sarcoma (n = 44) and atypical leiomyoma (n = 94) were retrospectively collected from four institutions. The cohort was randomly divided into training (84/138, 60.0%) and validation (54/138, 40.0%) sets. Two independent readers evaluated six qualitative MRI features and two DWI-based quantitative parameters for each index tumor. Multivariable logistic regression was used to identify the relevant qualitative MRI features. Diagnostic classifiers based on qualitative MRI features alone and in combination with DWI-based quantitative parameters were developed using a logistic regression algorithm. The diagnostic performance of the classifiers was evaluated using a cross-table analysis and calculation of the area under the receiver operating characteristic curve (AUC). RESULTS: Mean apparent diffusion coefficient value of uterine sarcoma was lower than that of atypical leiomyoma (mean ± standard deviation, 0.94 ± 0.30 10-3 mm²/s vs. 1.23 ± 0.25 10-3 mm²/s; P < 0.001), and the relative contrast ratio was higher in the uterine sarcoma (8.16 ± 2.94 vs. 4.19 ± 2.66; P < 0.001). Selected qualitative MRI features included ill-defined margin (adjusted odds ratio [aOR], 17.9; 95% confidence interval [CI], 1.41-503, P = 0.040), intratumoral hemorrhage (aOR, 27.3; 95% CI, 3.74-596, P = 0.006), and absence of T2 dark area (aOR, 83.5; 95% CI, 12.4-1916, P < 0.001). The classifier that combined qualitative MRI features and DWI-based quantitative parameters showed significantly better performance than without DWI-based parameters in the validation set (AUC, 0.92 vs. 0.78; P < 0.001). CONCLUSION: The addition of DWI-based quantitative parameters to qualitative MRI features improved the diagnostic performance of the logistic regression classifier in differentiating uterine sarcomas from atypical leiomyomas on preoperative MRI.

Acute left iliofemoral vein thrombosis: Comparison between simple and bony May-Thurner syndrome in CT venography.

OBJECTIVES: To explore the etiology of May-Thurner syndrome (MTS) with acute iliofemoral deep vein thrombosis (DVT) regarding imaging findings and clinical features. METHODS: We retrospectively analyzed 57 patients with acute left iliofemoral DVT from 2015 to 2020. The diameter of left common iliac vein (LCIV) at the maximal compression site and its percent compression regarding the average diameter of the uncompressed iliac vein were recorded in central and distal portions of the LCIV according to the location in the quadrant of lumbar vertebral body. Compression was categorized into simple and bony MTS; Simple MTS as LCIV compressed by the right common iliac artery (RCIA) versus Bony MTS as LCIV by lower lumbar degenerative changes regardless of RCIA compression. Initial computed tomographic venography (CTV) regarding chronic change of LCIV such as fibrotic atrophy or cordlike obliteration, extent of thrombus, and lumbar degenerative changes were evaluated. Therapeutic effect after initial therapy was assessed in follow-up CTVs after 3-6 months. RESULTS: All patients showed LCIV compression with 19 simple MTS (mean age, 42.8 ± 14.1 years [23-67 years]; 12 females; symptom for 4.4 ± 5.5 days) and 38 bony MTS (mean age, 73.0 ± 10.2 years [49-85 years]; 26 females; symptom for 5.5 ± 4.8 days). There was significant difference in age (p < .001) and no significant difference in sex or symptom duration between two groups (p = .691 and 0.415, respectively). All simple MTS showed compression only in the central LCIV and half of bony MTS showed compression in both central and distal LCIV (p < .001). Among the lumbar degenerative changes, symmetric anterolateral osteophyte (p < .001) and asymmetric osteophyte (p < .001) were significantly associated with bony MTS, but not scoliosis (p = .799), compared to simple MTS. Although there was no significant difference in chronic change of LCIV, thrombosis extent, and therapeutic effect between two groups (p > .05), chronic change of LCIV showed significant difference between single and dual compression (23.7% vs. 57.9%, p = .024) and residual thrombus after initial therapy was occurred in 21.1% of single compression and 47.4% in dual compression with non-significant trend (p = .082). CONCLUSION: Bony MTS related to lumbar degenerative changes with acute iliofemoral DVT occurs in older patients, presenting more than one stenosis at LCIV, inducing more chronic change with possibly weaker therapeutic effect than simple MTS.

Extramedullary Infiltration in Pediatric Acute Myeloid Leukemia on Surveillance Magnetic Resonance Imaging and its Relationship With Established Risk Factors.

PURPOSE: Extramedullary infiltration (EMI) is a rare condition defined by the accumulation of myeloid tumor cells beyond the bone marrow. The clinical significance is still controversial. This study was aimed to evaluate the incidence, characteristics, and prognostic significance of EMI on complete magnetic resonance imaging (MRI) investigation in newly diagnosed pediatric acute myeloid leukemia (AML) patients who are asymptomatic without clinical evidence to suspect EMI. MATERIALS AND METHODS: Retrospective clinical and radiologic review of 121 patients with MRI examination at the time of initial diagnosis of AML without any clinical evidence suggestive of EMI was performed. Patients were divided into 2 groups according to the presence or absence of EMI, and the relationship between EMI and established risk factors was analyzed. Initial white blood cell count, the occurrence of an event (including relapse, death, and primary refractory disease), survival status, and detailed information on cytogenetic/molecular status was performed by a thorough review of electronic medical records system. All patients underwent full imaging evaluation with the contrast-enhanced whole body and some regional MRI at the time of initial diagnosis. RESULTS: The median age at diagnosis was 10.77 years (range, 0.37 to 18.83 y). Based on the risk stratification system of AML, 36, 45, and 40 patients are classified as low-risk, intermediate-risk, and high-risk groups, respectively. MRI at the time of the initial diagnosis of AML revealed 35 of 121 patients (28.9%) with EMI. The most common site of EMI was a skull, followed by the lower extremity bone and meninges of the brain. The median age at diagnosis was significantly younger in patients with EMI (7.87 vs. 11.08 y, P=0.0212). Low incidence of FLT3/ITD mutation, low incidence of AML-ETO gene rearrangement, and the larger extent and more severe degree of bone marrow involvement was related with EMI. However, there was no significant prognostic difference in event-free survival and overall survival regardless of the presence of EMI in the overall patient population and each risk group. The location of EMI occurrence was also not related to prognosis. CONCLUSIONS: Even if EMI symptoms are not evident, surveillance MRI scans at the initial diagnosis of pediatric AML patients are very helpful in detecting a significant number of EMIs. Younger age, some molecular features, and more severe bone marrow involvement of AML patients were related with EMI. However, there was no significant prognostic difference between patients with or without EMI regardless of risk group. Further prospective investigation is necessary to validate the prognostic effect of EMI in a larger group of patients with different risk groups.

Convolutional neural network-based reconstruction for acceleration of prostate T2 weighted MR imaging: a retro- and prospective study.

OBJECTIVE: The aim of this study was to develop a deep neural network (DNN)-based parallel imaging reconstruction for highly accelerated 2D turbo spin echo (TSE) data in prostate MRI without quality degradation compared to conventional scans. METHODS: 155 participant data were acquired for training and testing. Two DNN models were generated according to the number of acquisitions (NAQ) of input images: DNN-N1 for NAQ = 1 and DNN-N2 for NAQ = 2. In the test data, DNN and TSE images were compared by quantitative error metrics. The visual appropriateness of DNN reconstructions on accelerated scans (DNN-N1 and DNN-N2) and conventional scans (TSE-Conv) was assessed for nine parameters by two radiologists. The lesion detection was evaluated at DNNs and TES-Conv by prostate imaging-reporting and data system. RESULTS: The scan time was reduced by 71% at NAQ = 1, and 42% at NAQ = 2. Quantitative evaluation demonstrated the better error metrics of DNN images (29-43% lower NRMSE, 4-13% higher structure similarity index, and 2.8-4.8 dB higher peak signal-to-noise ratio; p < 0.001) than TSE images. In the assessment of the visual appropriateness, both radiologists evaluated that DNN-N2 showed better or comparable performance in all parameters compared to TSE-Conv. In the lesion detection, DNN images showed almost perfect agreement (κ > 0.9) scores with TSE-Conv. CONCLUSIONS: DNN-based reconstruction in highly accelerated prostate TSE imaging showed comparable quality to conventional TSE. ADVANCES IN KNOWLEDGE: Our framework reduces the scan time by 42% of conventional prostate TSE imaging without sequence modification, revealing great potential for clinical application.

Deep learning-accelerated T2-weighted imaging of the prostate: Impact of further acceleration with lower spatial resolution on image quality.

PURPOSE: To compare image quality in prostate MRI among standard T2-weighted imaging (T2-std), accelerated T2-weighted imaging (T2WI) with high resolution (T2-HR) and more accelerated T2WI with lower resolution (T2-LR) using both conventional reconstruction (C) and deep learning reconstruction (DL). MATERIALS AND METHODS: In 46 consecutive patients, T2-std, T2-HR and T2-LR were acquired in 3:32 min, 1:06 min and 0.52 min, respectively. Both reconstruction techniques (C and DL) were applied to T2-HR and T2-LR. Five sets of images (T2-std, T2-HRC, T2-LRC, T2-HRDL, and T2-LRDL) for each patient were independently evaluated by two radiologists. Quantitative analysis including the signal-to-noise ratio (SNR) and contrast ratio (CR) and qualitative analysis with a 5-point scale for the sharpness of structures, ghosting or other artifacts, noise and overall image quality were performed. RESULTS: The SNR was not different in either the peripheral zone (PZ) or transition zone (TZ) between T2-LRDL and T2-std with the median value of 21.7 versus 22.6 in PZ and 16.5 versus 17.3 in TZ, respectively. The CR between the prostate gland and muscle was significantly lower on T2-HRC and T2-LRC than on T2-std. Most of the evaluated factors showed significantly lower scores on T2-HRC and T2-LRC than on T2-std. Although noise and overall image quality on T2-HRDL and other artifacts on T2-LRDL were rated significantly lower than on T2-std (median value 4.0 versus 4.5, P < 0.001; 4.5 versus 5.0, P = 0.001; 4.5 versus 5.0, P = 0.006, respectively), other factors did not differ between T2-std and T2-HRDL or T2-LRDL. CONCLUSION: DL is useful to improve image quality in accelerated T2WI of the prostate gland. Using DL, accelerated T2WI with lower spatial resolution than T2-std can be achieved with similar image quality in much shorter scan time (75.5% reduction in the acquisition time).

Application of manual aspiration thrombectomy in the treatment of deep vein thrombosis in cancer patients: Descriptive retrospective cohort study.

OBJECTIVES: To determine the outcomes and feasibility of endovascular treatment, mainly based on manual aspiration thrombectomy (MAT) with adjunctive percutaneous balloon angioplasty with or without stent deployment, for treatment of symptomatic ilio-femoral deep vein thrombosis (IFDVT) in cancer patients. MATERIALS AND METHODS: In this retrospective cohort study, 135 consecutive patients (56 men; mean age, 63 years; 149 limbs) with acute (n = 113; 83.7%) and subacute to chronic (n = 22; 16.3%) symptomatic IFDVT underwent MAT-based endovascular treatment. Among them, adjunctive balloon angioplasty and stent placement was performed in 94 patients. Technical and clinical success regarding stage and cause of DVT was assessed. RESULTS: Technical success (complete thrombus removal without residual thrombus or stenosis) was achieved in 89.6%, and subjective symptom improvement was stated by 71.5% of treated patients. The primary patency rates were 88.1%, 81.6%, 76.0%, 74.1% and 69.1% at 1, 3, 6, 12, and 30 months, respectively. Recurrent IFDVT occurred in 19.3% (26/135) of patients, 0.79 cases per patients-years of follow up. According to the analysis by causes of IFDVT, recurrence rate was 19.3% (11/57), 21.2% (12/57), and 14.3% (3/21) in unknown, compression/invasion of the vein by cancerous mass, and May-Thurner syndrome groups, respectively (p = 0.798). No procedure-related complication developed. CONCLUSIONS: Endovascular treatment based on MAT is a feasible treatment option with favorable outcomes and minimal risk of complication in cancer patients with symptomatic IFDVT.

Usefulness of fusion images of unenhanced and contrast-enhanced arterial phase cone-beam CT in the detection of viable hepatocellular carcinoma during transarterial chemoembolization.

PURPOSE: We aimed to evaluate the diagnostic efficacy of fusion imaging of unenhanced and arterial phase contrast-enhanced cone-beam computed tomography (CBCT) by comparing with multidetector computed tomography (MDCT) in detection of viable hepatocellular carcinoma (HCC) in patients who have been previously treated with transarterial chemoembolization (TACE). METHODS: In this retrospective study, a total of 173 tumors in 33 known HCC patients (21 men, 12 women; mean age, 64±7.6 years; mean tumor size, 2.15±1.70 cm) who had been previously treated with TACE and underwent additional session of TACE were included. The sensitivity and positive predictive values of preprocedural MDCT and fusion CBCT for detection of viable tumor were analyzed with follow-up MDCT images performed 3-4 weeks after TACE, as reference standard. RESULTS: A total of 141 remote and 32 marginal viable tumors were included. The sensitivities for detection of remote, marginal, and total viable tumors were 80.9%, 68.8%, and 78.6% for MDCT and 96.5%, 96.9%, and 96.5% for fusion CBCT, respectively. The positive predictive values for detection of remote, marginal, and total viable tumors were 95.0%, 78.6%, and 95.8% for MDCT, and 97.1%, 88.6%, and 97.7% for fusion CBCT, respectively. Fusion CBCT showed statistically higher sensitivity and positive predictive value for detection of viable tumors (P < 0.001). CONCLUSION: The diagnostic performance of fusion imaging of unenhanced and contrast-enhanced arterial phase CBCT was superior to MDCT for detection of viable HCCs.

Extraluminal Recanalization of Bile Duct Anastomosis Obstruction after Liver Transplantation.

This report describes extraluminal recanalization of bile duct anastomosis obstruction after living donor liver transplantation. The procedure was performed in 5 patients in whom negotiation of the biliary anastomotic obstruction by retrograde endoscopic approach and percutaneous intraluminal recanalization had failed. Extraluminal puncture from the donor bile duct to the recipient side bile duct was made with the stiff back end of a 0.035-inch hydrophilic guide wire. After recanalization, a percutaneous transhepatic biliary drainage catheter was placed through the created tract. In all 5 patients, extraluminal recanalization was achieved without major complication, and endoscopic plastic stents were subsequently placed along the tract.

Primary and Secondary Percutaneous Ureteral Stent Placement: Comparison of Stent Patency and Clinical Outcome.

OBJECTIVES: To compare early double J ureteral stent (DJUS) dysfunction rate and long-term patency between two percutaneous ureteral stent placement methods: single-stage (primary) or two-stage (secondary) procedures. METHODS: A total of 250 (176 primary and 74 secondary) DJUS placements performed on interventional unit were retrospectively reviewed between February 2008 and March 2014. Early DJUS dysfunction was defined as no passage of contrast media into the urinary bladder in 2-3 days after placement. Long-term patency was considered if the ureteral stent functioned for 3 months (time point for a first routine DJUS change). Amount of blood retained in the collecting system was scored on nephrostogram immediately after DJUS placement with three levels of score. RESULTS: The overall early DJUS dysfunction rate and long-term patency rate were 30.8 and 96.7%. The early DJUS dysfunction rates were similar in primary and secondary DJUS placements (30.7 and 31.1%, P = 0.950). The long-term patency rates were similar in primary and secondary groups (96.2 and 97.9%, P = 0.928). The amount of blood retained in the collecting system between primary and secondary groups was not significantly different. The early DJUS dysfunction rate significantly increased with increasing blood retention. CONCLUSIONS: The early DJUS dysfunction rates and long-term patency are similar in primary and secondary DJUS placement. However, the early DJUS dysfunction rate can be increased by increasing the blood retention in the collecting system.

The Monorail Technique to Overcome Difficult Anatomical Course During Implantation of Central Venous Port via the Left Internal Jugular Vein.

PURPOSE: The study aimed to introduce a monorail technique to overcome difficult anatomical course via left internal jugular vein in implantable port insertion. METHODS: From 2007 to 2016, a total of 9346 patients were referred for implantable port insertion in our interventional unit, among which 79 cases were requested to insert on the left side. Our monorail technique was applied only when the technical challenge of the catheter tip entering the azygos vein instead of the superior vena cava occurred (n = 7). The technique consists of puncturing at the distal tip of the port catheter with a 21-gauge micropuncture needle and advancing a 0.018-in. hair-wire to guide and provide support for pre-assembled port. RESULTS: The monorail technique was performed in seven patients and all but one case were technically successful, showing a technical success rate of 85.7%. There were no immediate or delayed complications. CONCLUSIONS: The monorail technique is helpful to overcome the difficult anatomical course via left internal jugular vein in implantable port insertion.

CT and MR imaging findings of hepatic epithelioid hemangioendotheliomas: emphasis on single nodular type.

PURPOSE: To evaluate imaging findings of hepatic epithelioid hemangioendothelioma (HEH), with emphasis on solitary form at the initial presentation. MATERIALS AND METHODS: Ten cases of pathologically confirmed HEH were retrospectively reviewed; seven patients had CT and MR images and three had only CT images. Two radiologists assessed the followings in consensus: lesion number, size, location, presence of capsular retraction and calcification, attenuation, signal intensity, and enhancement pattern. RESULTS: Initially, HEHs manifested as a single mass (n = 5) or multiple masses (n = 5). One case demonstrated a solitary nodule at first, which subsequently transformed to multifocal nodules on serial follow-up. The maximal diameter of the lesions ranged from 1.8 to 10 cm (mean 4.2 cm). All cases showed predominant subcapsular location. Capsular retraction was seen in multinodular types, but not in solitary types. Two patients had intra-lesional calcifications. HEHs showed minimal enhancement (7/7 patients) on the hepatic arterial phase CT and rim-like enhancement (5/10 patients), minimal enhancement (2/10 patients), multilayered target enhancement (2/10 patients), and peripheral nodular enhancement (1/10 patients) on the portal venous phase CT. On MR images (n = 7), HEHs showed hypointensity on T1-weighted images and hyperintensity on T2-weighted images. Dynamic contrast-enhanced MR images revealed progressive centripetal fill-in enhancement (7/7 patients). On Gd-EOB-DTPA-enhanced hepatobiliary phase images, HEH manifested as homogeneous hypointensity (3/5 patients) and target-shaped hypointensity (2/5 patients). CONCLUSION: HEH can manifest as single nodular, multinodular, or diffuse type. Common imaging features of HEH are multiple subcapsular nodules with coalescence, capsular retraction, peripheral, and delayed enhancement. However, HEH can manifest as a solitary subcapsular mass with minimal or rim-like enhancement at early phase and progressive centripetal fill-in enhancement during dynamic phase imaging, representing early stage of HEH. A single nodular type can progress to multifocal nodular type during follow-up.

Aggressive primary thyroid lymphoma: imaging features of two elderly patients.

We report two cases of aggressive thyroid lymphoma in elderly patients that presented as large infiltrative thyroid masses with extensive invasion to adjacent structures including trachea, esophagus, and common carotid artery. Ultrasonography displayed irregular shaped, heterogeneous hypoechoic mass, mimicking anaplastic carcinoma. Computed tomography showed heterogeneously enhancing mass compared to surrounding muscles without calcification and hemorrhage. After biopsy, the masses were histopathologically diagnosed as lymphoma. Aggressive primary thyroid lymphoma is rare; therefore, here we report its image features, with emphasis on ultrasonographic findings, and discuss its differential diagnosis.