Get Connected!

Be part of the largest network for Radiology professionals!

Journal of Computer Assisted Tomography - Current Issue

Journal of Computer Assisted Tomography - Current Issue
  1. Dual-Energy CT: Balance Between Iodine Attenuation and Artifact Reduction for the Evaluation of Head and Neck Cancer
    imageObjective: Dual-energy computed tomography high energy virtual monochromatic images (VMIs) can reduce artifact but suppress iodine attenuation in enhancing tumor. We investigated this trade-off to identify VMI(s) that strike the best balance between iodine detection and artifact reduction. Methods: The study was performed using an Alderson radiation therapy phantom. Different iodine solutions (based on estimated tumor iodine content in situ using dual-energy computed tomography material decomposition) and different dental fillings were investigated. Spectral attenuation curves and quality index (QI: 1/SD) were evaluated. Results: The relationship between iodine attenuation and QI depends on artifact severity and iodine concentration. For low to average concentration solutions degraded by mild to moderate artifact, the iodine attenuation and QI curves crossed at 95 keV. Conclusions: High energy VMIs less than 100 keV can achieve modest artifact reduction while preserving sufficient iodine attenuation and could represent a useful additional reconstruction for evaluation of head and neck cancer.



  2. Maximum Arterial Contrast Concentrations With Computed Tomography and Left Ventriculography: Implications for Contrast Nephrotoxicity Risk
    imagePurpose: Contrast nephropathy occurs more frequently after cardiac angiography, which usually includes left ventriculography via direct left ventricular injection, than after contrast-enhanced computed tomography (CT), despite the usually higher intravenous contrast dose used for CT. To determine whether maximum renal arterial contrast concentration is higher after left ventriculography, we assessed this parameter for both procedures. Materials and Methods: Contrast concentration in abdominal aortic blood during contrast-enhanced CT was measured by performing CT densitometry of aortic blood before contrast, and in the arterial phase, in 100 adults undergoing abdominal CT. Densities were converted to contrast concentrations by scanning water phantoms containing 20 graded concentrations of contrast and comparing their densities to patient data. Because it was impossible to perform CT densitometry during cardiac angiography, aortic contrast concentrations were calculated from standard contrast doses and injection rates with the range of clinically encountered cardiac output rates, assuming ultimate steady state for blood/contrast mixing and normal data distribution. Results: Maximum aortic (and hence renal arterial) concentrations were significantly higher (range, 6.68%–15.90%) after ventriculography than after CT (1.22%–5.80%). Because ventricular injection times are much shorter than published initial-appearance-to-maximum-concentration times after intravenous administration, the rate of change of contrast concentration is also higher after ventriculography than after CT. Conclusion: Higher maximum renal arterial contrast concentration may be responsible for the greater risk of nephropathy after cardiac angiography than after doses for CT. The faster rate of change of renal arterial contrast concentration after ventriculography may also increase the likelihood of renal toxicity. Clinical Relevance/Application: Maximum renal arterial contrast concentration, and/or the rapidity of change of this parameter, may be partly responsible for the risk of nephropathy. Controlling these factors might permit reduction of nephropathy risk; they also suggest avenues of research into the pathophysiology of contrast nephropathy.



  3. The Association of Intracranial Vascular Calcification and Stenosis With Acute Ischemic Cerebrovascular Events
    imageObjective: The aim of this article was to evaluate the association of intracranial artery calcification (IAC) with acute downstream ischemic stroke (dAIS)/transient ischemic attack while considering stenosis. Methods: Consecutive stroke computed tomography angiography head/neck examinations from January 2010 to April 2010 were reviewed. Per-vessel IAC and stenosis of greater than or equal to 30% were documented by 2 neuroradiologists. Associations between calcification and dAIS were assessed using multivariate logistic regression, controlling for traditional risk factors and stenosis. Results: A total of 1287 arterial segments from 99 patients were reviewed. Intracranial artery calcification was significantly associated with dAIS (odds ratio [OR], 2.2; P = 0.009). This association persisted among nonstenotic arteries, with significantly higher likelihood of dAIS for arteries with IAC than those without (OR, 2.5; P = 0.009). However, among stenotic arteries, calcified stenoses had a lower association of dAIS than noncalcified stenoses (OR, 0.55; 95% confidence interval, 0.17–1.8; P = 0.33). Conclusions: Without concurrent stenosis, IAC is a significant risk factor for dAIS. When stenosis is present, IAC does not increase the association with dAIS. Stenotic and nonstenotic calcifications may represent different disease processes, as represented in the histology literature.



  4. Analysis of a Steerable Needle for Fine Needle Aspiration and Biopsy: Efficiency and Radiation Dose Compared With a Conventional Straight Needle
    imagePurpose: Percutaneous computed tomography (CT)–guided needle biopsy has proven to be an efficacious method for sampling of many soft tissue lesions, especially deep-seated masses in the abdomen and pelvis. This study sought to test the potential for a novel steerable needle to improve localization and to reduce procedure duration and radiation dose compared with a conventional straight needle. Material and Methods: A fresh, raw meat sample (lean bovine flank) was imbedded with cylindrical radiopaque and radiolucent obstacles designed to simulate vessels (radiolucent objects) and bones (radiopaque objects) on CT. A pit-containing olive (partially radiopaque) was imbedded beyond the obstacles to represent the target. Two sites on the surface of the meat were selected and marked to determine initial needle placement. Two radiologists with different levels of experience proceeded to position a straight needle and the steerable needle from each skin site to the target using CT guidance as efficiently as possible, avoiding the obstacles. The total positioning time, the number of CT scans required for positioning, and the number of repositioning events (partial withdrawal followed by advancement) were tracked for the straight and steerable needles. Results: For the straight needle, total time to reach the target was 499 to 667 seconds (mean, 592 seconds); for the steerable needle, total time to reach the target was 281 to 343 seconds (mean, 309 seconds), on average, 48% lower. The number of CT scans needed for needle positioning averaged 6.25 for the straight needle and 3.5 for the steerable needle, which is 44% lower. Repositioning events (withdrawing and readvancing the needle) ranged from 3 to 10 for the straight needle (mean, 6.5) and 0 for the steerable needle. Conclusions: Using an in vitro model embedded with obstacles, the steerable needle performed better than a straight needle with regard to procedure time, needle repositioning events, and CT scans required for placement.



  5. Noncontrast Hybrid Arterial Spin-Labeled Imaging of the Intracranial Arteries
    imageObjective: The purpose of this study is to evaluate feasibility, image quality (IQ), and accuracy of noncontrast hybrid arterial spin labeling (NoHASL) magnetic resonance angiography (MRA) compared with time of flight (TOF) MRA and contrast-enhanced (CE) MRA in patients with known/suspected cerebrovascular ischemia. Methods: Thirty inpatients were imaged at 1.5 T. Two neuroradiologists assessed 630 intracranial arterial segments for IQ (1, nondiagnostic; 3, satisfactory for diagnosis; and 5, excellent). Hemodynamically significant stenosis (>50%) was assessed against all combined techniques as reference. Results: The NoHASL MRA IQ was diagnostic (3.32 ± 0.86) but affected by signal to noise ratio and spatial resolution limitations and significantly inferior to TOF (3.48 ± 0.68) and CE MRA (3.44 ± 0.78) (P < 0.0001 in both comparisons). Fourteen (2.2%) of 630 segments had hemodynamically significant stenoses at the reference standard. Sensitivity/specificity was not significantly different between techniques: NoHASL MRA, 67.9%/90.0%; TOF MRA, 67.9%/97.7%; and CE MRA, 50.0%/98.7%. Conclusions: The NoHASL MRA is feasible, with diagnostic quality imaging of proximal intracranial vessels. Low disease prevalence limited the assessment of technique accuracy.


  6. Dual-Energy Computed Tomography in Stroke Imaging: Technical and Clinical Considerations of Virtual Noncontrast Images for Detection of the Hyperdense Artery Sign
    imageObjective: The technical feasibility of virtual noncontrast (VNC) images from dual-energy computed tomography (DECT) for the detection of the hyperdense artery sign (HAS) in ischemic stroke patients was investigated. Methods: True noncontrast (TNC) scans of 60 patients either with or without HAS (n = 30 each) were investigated. Clot presence and characteristics were assessed on VNC images from DECT angiography and compared with TNC images. Clot characterization included the level of confidence for diagnosing HAS, a qualitative clot burden score, and quantitative attenuation (Hounsfield unit [HU]) measurements. Results: Sensitivity, specificity, and accuracy of VNC for diagnosing HAS were 97%, 90%, and 93%, respectively. No significant differences were found regarding the diagnostic confidence (P = 0.18) and clot burden score (P = 0.071). No significant HU differences were found among vessels with HAS in VNC (56 ± 7HU) and TNC (57 ± 8HU) (P = 0.691) images. Conclusions: Virtual noncontrast images derived from DECT enable an accurate detection and characterization of HAS.



  7. Neuro–Magnetic Resonance Imaging in Hand, Foot, and Mouth Disease: Finding in 412 Patients and Prognostic Features
    imagePurpose: The aims of this study were to describe the neuroimaging findings in hand, foot, and mouth disease and determine those who may provide prognosis. Material and Methods: Magnetic resonance imaging scans in 412 severe hand, foot, and mouth disease between 2009 and 2014 were retrospectively evaluated. The patients who had the neurological signs were followed for 6 months to 1 year. According to the good or poor prognosis, 2 groups were categorized. The incidence of lesions in different sites between the 2 groups was compared, and multivariate analysis was used to look for risk factors. Results: The major sites of involvement for all patients with percentages were the medulla oblongata (16.1%), spinal anterior nerve roots (12.4%), thoracic segments (11.1%), brain or spinal meninges (8.3%), and so on. There were 347 patients (84.2%) with good prognosis and 65 (15.8%) with poor prognosis in the follow-up. There was a significantly higher rate of lesions involving the cerebral white substance, thalamus, medulla oblongata, pons, midbrain, and spinal cord in the group with poor prognosis. Multivariate analysis showed 2 independent risk factors associated with poor prognosis: lesions located in the medulla oblongata (P < 0.015) and spinal cord (P < 0.001) on magnetic resonance imaging; the latter was the most significant prognostic factor (odds ratio, 29.11; P < 0.001). Conclusions: We found that the distribution patterns for all patients mainly involved the medulla oblongata, spinal anterior nerve roots, thoracic segments, and brain or spinal meninges. Our findings suggested that patients with lesions located in the medulla oblongata and spinal cord may be closely monitored for early intervention and meticulous management. For children with the symptom of nervous system, they are strongly recommended for magnetic resonance examination.



  8. An Assembled Prototype Multimaterial Three-Dimensional–Printed Model of the Neck for Computed Tomography– and Ultrasound-Guided Interventional Procedures
    imageAbstract: A low-cost, semirealistic, multimaterial prototype phantom of the neck was developed for computed tomography– and ultrasound-guided interventions, using three-dimensional (3D) printing with a variety of materials as well as through molding techniques. This dual-modality phantom can be used by trainees for practicing procedures and can also serve as a prototype for developing more complex and realistic 3D-printed models, particularly with the continued development and advancement in multimaterial 3D printing technologies.



  9. Effects of B Value on Quantification of Rapid Diffusion Kurtosis Imaging in Normal and Acute Ischemic Brain Tissues
    imagePurpose: Diffusion kurtosis imaging (DKI) has been widely used to characterize brain tissue alterations. Diffusion-weighting factor or b value plays an important role in the measurement of rapid DKI and may have influential effects on them. The purpose of this study was to investigate the effects of b value on rapid DKI indices in normal and acute ischemic brain tissues. Materials and Methods: This study enrolled 10 healthy subjects and 4 acute ischemic stroke patients. Three repeated DKI data with 6 high b values (500, 750, 1000, 1500, 2000, 3000 s/mm2) were acquired from healthy subjects, whereas nonrepeated DKI data with 3 high b values (1000, 2000, 3000 s/mm2) were acquired from ischemic stroke patients. The DKI datasets were decomposed into several rapid DKI datasets consisting of 1 b0 and 2 high b values for comparisons. Results: The results showed that b value significantly impacted the reproducibility and accuracy of DKI indices. The comparisons demonstrated that DKI with b = (0, 1000, 3000) s/mm2 exhibited more reproducible and accurate DKI indices than other DKI datasets in normal brain tissues, and similar results were noticed in acute ischemic brain tissue. Conclusions: We concluded that b value significantly impacted the quantification of DKI indices in both normal and acute ischemic brain tissues.



  10. The Peculiar Case of a Large Right Lower Quadrant Solitary Fibrous Tumor With Vasculature Arising from the Splenic Artery and Vein
    imageAbstract: We present the interesting case of a patient with peritoneal solitary fibrous tumor (SFT). The patient initially presented with right lower quadrant pain. Computed tomography findings revealed the presence of a large mass near the cecum, with both arterial and venous blood supply arising directly from the splenic artery and vein. The patient ultimately underwent surgical excision of the mass, and pathological examination was consistent with benign SFT. Not only is the location of our patient's tumor exceedingly rare, but also, to our knowledge, it is the first reported case of SFT with such a unique vascular supply.


  11. T2*-Weighted and Diffusion Magnetic Resonance Imaging Differentiation of Cerebral Fat Embolism From Diffuse Axonal Injury
    imageObjective: This study differentiates cerebral fat embolism (CFE) and diffuse axonal injury (DAI) on diffusion-weighted magnetic resonance imaging (DWI) and T2*-weighted magnetic resonance imaging. Methods: Consecutive CFE and DAI cases were retrospectively selected. Hemorrhages were characterized by number, size/shape, and distribution, whereas DWI lesions by pattern. The number of hemorrhages was compared using the Mann-Whitney test with adjustment for multiple comparisons, whereas DWI abnormality was compared using Fisher exact test. Results: Seven CFE and 20 DAI patients were included. Cerebral fat embolism had significantly more hemorrhages than DAI (mean, 670 ± 407 vs 136 ± 87; P = 0.01), particularly in the frontal (P = 0.025), parietal (P = 0.002), and occipital lobes (P = 0.01), the corpus callosum (P = 0.01), and cerebellum (P = 0.01). Cerebral fat embolism microhemorrhages were punctate/round, whereas DAI hemorrhages were small/medium sized (P < 0.001) and linear (P = 0.001). On DWI, DAI typically had few scattered abnormalities, whereas CFE had confluent abnormalities (P < 0.05). Conclusions: Magnetic resonance imaging can differentiate CFE from DAI. Cerebral fat embolism demonstrates more hemorrhages. Larger or linear hemorrhages favor DAI. Diffuse confluent diffusion restriction favors CFE, whereas few scattered foci favor DAI.



  12. Investigation on Computed Tomography Features of Primary Thymic Atypical Carcinoid Tumors
    imageObjectives: The thymic atypical carcinoid tumors (aTCs) are rare. The computed tomography (CT) features of aTC were poorly studied, and researches under this topic with large samples are in a small quantity in the literature. Our aim was to investigate the CT features of aTC. Methods: Eleven cases of aTC (7 men and 4 women; mean age, 56 ± 16 years) proved by pathology were retrospectively analyzed. All the patients underwent contrast-enhanced CT scans with dual phase (25–30 and 60–70 seconds) after contrast agent injection. Two experienced radiologists analyzed the imaging findings. The observing indexes of CT features were based on standard CT reporting terms of mediastinal masses suspicious for thymic malignancy, particularly on the findings of marginal cystic/necrotic component (MCC) sign and hypervascular sign in tumors. Results: All the tumors were located in the anterior and/or middle mediastinum and heterogeneous parenchyma, with moderate to marked enhancement, and had multiple cystic/necrotic components. The maximum diameter of lesions ranged from 5 to 24 cm. Among the 11 patients involved in this study, 6 patients had distant metastases, all of which were identified as skeletal metastases; 9 cases showed MCC sign only at the margin (3 cases) or at both marginal and central margins (6 cases), and 5 cases showed hypervascular sign. Conclusions: Our results suggested that the MCC and hypervascular signs should be included as characterization in addition to the standard features for the diagnosis of aTC.



  13. Iterative Reconstruction Designed for Brain CT: A Correlative Study With Filtered Back Projection for the Diagnosis of Acute Ischemic Stroke
    imageObjectives: The objective of this study is to evaluate the usefulness of iterative model reconstruction designed for brain computed tomography (CT) (IMR-Neuro) for the diagnosis of acute ischemic stroke. Methods: This retrospective study included 20 patients with acute middle cerebral artery infarction who have undergone brain CT and 20 nonstroke patients (control). We reconstructed axial images with filtered back projection (FBP) and IMR-Neuro (slice thickness, 1 and 5 mm). We compared the CT number of the infarcted area, the image noise, contrast, and the contrast to noise ratio of the infarcted and the noninfarcted areas between the different reconstruction methods. We compared the performance of 10 radiologists in the detection of parenchymal hypoattenuation between 2 techniques using the receiver operating characteristic (ROC) techniques with the jackknife method. Results: The image noise was significantly lower with IMR-Neuro [5 mm: 2.5 Hounsfield units (HU) ± 0.5, 1 mm: 3.9 HU ± 0.5] than with FBP (5 mm: 4.9 HU ± 0.5, 1 mm: 10.1 HU ± 1.4) (P < 0.01). The contrast to noise ratio was significantly greater with IMR-Neuro (5 mm: 2.6 ± 2.1, 1 mm: 1.6 ± 1.3) than with FBP (5 mm: 1.2 ± 1.0; 1 mm: 0.6 ± 0.5) (P < 0.01). The value of the average area under the receiver operating curve was significantly higher with IMR-Neuro than FBP (5 mm: 0.79 vs 0.74, P = 0.04; 1 mm: 0.76 vs 0.69, P = 0.04). Conclusions: Compared with FBP, IMR-Neuro improves the image quality and the performance for the detection of parenchymal hypoattenuation with acute ischemic stroke.



  14. Interreader Reliability and Clinical Validity of a Magnetic Resonance Imaging Grading System for Cervical Foraminal Stenosis
    imageObjective: Park system is a magnetic resonance imaging (MRI) grading system for cervical neural foraminal stenosis (CNFS) and consists of 4 grades (0–3) based on the foraminal shape of 45-degree T2-weighted oblique sagittal images. The objective of this study was to evaluate the interreader reliability of the Park system among radiologists, residents, and clinicians. This study also assessed the correlations between radiologic and clinical findings. Material and Methods: A total of 289 patients (men:women = 155:134, mean age = 50 years) who underwent oblique sagittal MRI of the cervical spine at our hospital were included. According to the MR grading system suggested by Park et al (Br J Radiol 2013;86:20120515), 2 radiologists, 2 trainees, and 2 clinicians measured CNFS grade at the most narrow point. A neurosurgeon assessed the associated clinical manifestations. κ statistics were used to analyze the interreader agreement among the radiologists and clinicians. The clinical correlations between grade and positive clinical manifestations were assessed with R using nonparametric correlation analysis (Spearman correlation). Results: The overall interreader agreements between radiologists, between trainees, between clinicians, and between radiologists and clinicians were almost perfect (κ = 0.80–0.96). There were moderate correlations between grade and clinical manifestations in each group (R = 0.562–0.669). There were moderate to relatively high correlations between grade and neurologic manifestations based on cervical level (R = 0.570–0.715) (all P < 0.05). Conclusions: Regardless of reader experience, there was substantial to almost perfect interreader reliability with the Park system for CNFS based on oblique sagittal MRI.



  15. Venous Sinus Thrombosis in Blunt Trauma: Incidence and Risk Factors
    imagePurpose: The aim of our study was to determine the incidence and risk factors of dural venous sinus thrombosis and epidural hemorrhage in the setting of a blunt trauma causing a calvarial fracture crossing a dural venous sinus. Methods: A retrospective review of 472 blunt trauma patients with calvarial fracture crossing a dural venous sinus was performed. Two hundred ten patients who underwent computed tomography venography were identified and evaluated for the presence of dural venous sinus thrombosis and/or epidural hemorrhage. Site and displacement of fractures, as well as age, sex, Glasgow Coma Scale (GCS) score, and mechanism of injury, were considered for potential predictive value of thrombosis and/or epidural hemorrhage. Results: We found a 23% incidence of dural venous sinus thrombosis in patients with a fracture traversing a dural venous sinus. Significant predictors of thrombosis included temporal fracture (38% incidence) and skull base fracture (31% incidence). Occipital fracture not involving the skull base was associated with a significantly decreased risk of thrombosis, with an incidence of 9%. Decreased GCS score and fall from height greater than 10 feet additionally predicted dural venous sinus thrombosis. Significant predictors of epidural hemorrhage included parietal fractures and displaced fractures, although a large percentage of nondisplaced fractures in other bones demonstrated epidural hemorrhage as well. Conclusions: Dural venous sinus thrombosis in the setting of blunt trauma with a calvarial fracture crossing a dural venous sinus has an incidence of 23%. Increased suspicion for thrombosis is warranted in patients with temporal or skull base fractures, low GCS score, and recent fall from great height.


  16. Computed Tomography Features of Benign and Malignant Calcified Thyroid Nodules: A Single-Center Study
    imageObjective: No previous studies have investigated thyroid calcification on computed tomography (CT) quantitatively by using Hounsfield unit (HU) values. This study aimed to analyze quantitative HU values of thyroid calcification on preoperative neck CT and to assess the characteristics of benign and malignant calcified thyroid nodules (CTNs). Materials and Methods: Two hundred twenty patients who underwent neck CT before thyroid surgery from January 2015 to June 2016 were included. On soft-tissue window CT images, CTNs with calcified components of 3 mm or larger in minimum diameter were included in this study. The HU values and types of CTNs were determined and analyzed. Results: Of 61 CTNs in 49 patients, there were 42 malignant nodules and 19 benign nodules. The mean largest diameter of the calcified component was 5.3 (2.5) mm (range, 3.1–17.1 mm). A statistically significant difference was observed in the HU values of calcified portions between benign and malignant CTNs, whereas there was no significant difference in patient age or sex or in the size, location, or type of each CTN. Of the 8 CTNs with pure calcification, 3 exhibited a honeycomb pattern on bone window CT images, and these 3 CTNs were all diagnosed as papillary thyroid carcinoma on histopathological examination. Conclusions: Hounsfield unit values of CTNs may be helpful for differentiating malignancy from benignity.



  17. Quantitative Evaluation of Diffusion and Dynamic Contrast-Enhanced Magnetic Resonance Imaging for Differentiation Between Primary Central Nervous System Lymphoma and Glioblastoma
    imageObjective: This study aimed to evaluate the utility of diffusion and permeability parameters derived from diffusion-weighted imaging and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for differentiating primary central nervous system lymphoma (PCNSL) and glioblastoma multiforme (GBM) and to assess the correlation among these parameters. Materials and Methods: Forty-two patients with GBM and 18 patients with PCNSL underwent conventional 3.0-T MRI, diffusion-weighted imaging, and DCE-MRI before surgery. Normalized apparent diffusion coefficient ratio (rADC) and DCE-MRI–derived parameters (the volume transfer constant [Ktrans], the flux rate constant, the volume fraction of extravascular extracellular space [Ve], and the fractional plasma volume) were measured within the entire enhancing tumor and compared between the 2 groups. The diagnostic ability of each parameter and their optimal combination for differentiating between PCNSL and GBM, and the correlation among these parameters, were statistically analyzed. Results: The PCNSLs demonstrated significantly lower rADC (P = 0.000), higher Ktrans (P = 0.000), and higher Ve (P = 0.001) than GBMs. With the combination of rADC and Ktrans, the diagnostic ability for discriminating between PCNSL and GBM was significantly improved (area under the receiver operating characteristic curve [AUC] = 0.930) as compared with rADC (AUC = 0.858) and Ktrans (AUC = 0.852) alone (P < 0.001 for both). The rADC did not correlate with Ktrans or Ve derived from DCE-MRI. Conclusions: Apparent diffusion coefficient ratio, Ktrans, and Ve are useful parameters for differentiating between PCNSL and GBM. The combination of rADC and Ktrans helps to improve the diagnostic accuracy. The rADC may not show correlation with Ktrans or Ve.



  18. Reduced Field-of-View Diffusion-Weighted Magnetic Resonance Imaging of the Prostate at 3 Tesla: Comparison With Standard Echo-Planar Imaging Technique for Image Quality and Tumor Assessment
    imageObjective: The purpose of this study was to compare image quality and tumor assessment at prostate magnetic resonance imaging (MRI) between reduced field-of-view diffusion-weighted imaging (rFOV-DWI) and standard DWI (st-DWI). Methods: A total of 49 patients undergoing prostate MRI and MRI/ultrasound fusion–targeted biopsy were included. Examinations included st-DWI (field of view [FOV], 200 × 200 mm) and rFOV-DWI (FOV, 140 × 64 mm) using a 2-dimensional (2D) spatially-selective radiofrequency pulse and parallel transmission. Two readers performed qualitative assessments; a third reader performed quantitative evaluation. Results: Overall image quality, anatomic distortion, visualization of capsule, and visualization of peripheral/transition zone edge were better for rFOV-DWI for reader 1 (P ≤ 0.002), although not for reader 2 (P ≥ 0.567). For both readers, sensitivity, specificity, and accuracy for tumor with a Gleason Score (GS) of 3 + 4 or higher were not different (P ≥ 0.289). Lesion clarity was higher for st-DWI for reader 2 (P = 0.008), although similar for reader 1 (P = 0.409). Diagnostic confidence was not different for either reader (P ≥ 0.052). Tumor-to-benign apparent diffusion coefficient ratio was not different (P = 0.675). Conclusions: Potentially improved image quality of rFOV-DWI did not yield improved tumor assessment. Continued optimization is warranted.



  19. Differentiating Primary Central Nervous System Lymphomas From Glioblastomas and Inflammatory Demyelinating Pseudotumor Using Relative Minimum Apparent Diffusion Coefficients
    imageObjective: Our purpose was to evaluate the diagnostic performance of diffusion-weighted imaging, the relative minimum apparent diffusion coefficient (rADCmin) in differentiating primary central nervous system lymphomas (PCNSLs) from glioblastomas (GBMs) and inflammatory demyelinating pseudotumors (IDPs). Materials and Methods: Magnetic resonance images were reviewed retrospectively in 82 patients including 39 PCNSLs, 35 GBMs, and 8 IDPs. Regions of interest were drawn around the tumor on contrast-enhanced axial images; these images were transferred onto coregistered ADC maps to obtain the ADCmin, and the normalized ADCmin ratios (rADCmin) were calculated using the formula rADCmin = ADCmin of the lesion / ADCmin of the normal white matter. The rADCmin values were compared between PCNSLs, GBMs, and IDPs using the analysis of variance test. Receiver operating characteristic curves were constructed to evaluate the diagnostic performance of rADCmin values and to determine the optimum thresholds. Simple logistic regression was analyzed to evaluate the relationship between ADCs and tumor cellularity. Results: The rADCmin value was significantly lower in PCNSLs (0.675 ± 0.113) than GBMs (0.765 ± 0.059) and IDPs (0.834 ± 0.067) (PCNSL vs GBM, P < 0.001; PCNSL vs IDP, P < 0.001). Relative ADCmin was a significant assessor for differentiating PCNSLs from non-PCNCLs (P < 0.001). The optimal cutoff value was 0.722 (sensitivity, 74.5%; specificity, 74.1%; area under the curve, 0.803) on receiver operating characteristic analysis. A stronger negative correlation (r = −0.755, P = 0.000) was obtained between the cytoplasm and rADCmin. Conclusions: Relative ADCmin value is helpful in differentiating PCNSL from GBM and IDP. Thus, ADC values may provide a useful supplement to the information obtained from conventional contrast-enhanced magnetic resonance imaging and assist in future treatment planning.



  20. Magnetic Resonance Imaging of a Urethral Caruncle and the Pathologic Correlation: A Report of 3 Cases
    imageAbstract: A urethral caruncle is the most common disease of the urethra in postmenopausal women. A definitive diagnosis can usually be reached based on physical examination. Cross-sectional imaging is performed when malignant urethral tumor is suspected, such as a urethral carcinoma. No articles have discussed the detailed imaging of urethral caruncles. We present 3 patients with symptomatic urethral caruncles who underwent magnetic resonance imaging preoperatively.


: Terms of Use : : Privacy : : Safe Sender : : Contact Us : : Ask a question :