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Journal of Computer Assisted Tomography - Current Issue

Journal of Computer Assisted Tomography - Current Issue
  1. Diffusion-Weighted Imaging for Differentiating Uterine Leiomyosarcoma From Degenerated Leiomyoma
    imagePurpose: The study aimed to investigate magnetic resonance diffusion-weighted imaging (DWI) in the differentiation of uterine leiomyosarcoma (ULMS) from degenerated leiomyoma (DLM). Methods: Sixteen patients with ULMSs and 26 patients with DLMs confirmed by surgery and pathology underwent conventional magnetic resonance imaging and DWI. The mean apparent diffusion coefficient (ADC) values of the 2 groups’ tumors were measured and compared using an independent-sample t test (b = 0.1000 s/mm2 [ADC1]; b = 0.800 s/mm2 [ADC2], respectively). A receiver operating characteristic curve was used to evaluate the diagnostic performance of DWI in the differentiation of ULMS from DLM. Intraobserver and interobserver agreements were evaluated using an intraclass correlation coefficient and Bland-Altman analysis. Results: The mean ADC value in ULMSs (0.81 ± 0.14 × 10−3mm2/s [ADC1], 0.90 ± 0.11 × 10−3mm2/s [ADC2]) was significantly lower than that in DLMs (1.22 ± 0.22 × 10−3mm2/s [ADC1], 1.50 ± 0.22 × 10−3mm2/s [ADC2]) (P < 0.001, <0.001, respectively). The sensitivity, specificity, accuracy, and positive and negative predictive values for characterizing ULMS were 100%, 90%, 93%, and 83% and 100% [ADC1] and 100%, 93%, 96%, and 90% and 100% [ADC2]; respectively. Intraobserver and interobserver reproducibilities were excellent (intraclass correlation coefficient = 0.967–0.988; small variability and 95% limits of agreement). Conclusions: Diffusion-weighted imaging is helpful in differentiating ULMS from DLM.



  2. Fatal Congenital Retroperitoneal Neuroblastoma Diagnosed by Fetal Magnetic Resonance Imaging
    imageAbstract: Congenital extra-adrenal neuroblastoma is a rare condition, which typically has a favorable prognosis. We present a unique case of extra-adrenal retroperitoneal neuroblastoma diagnosed by fetal magnetic resonance imaging, which ultimately leads to fetal hydrops and neonatal death.



  3. Automated Infarct Core Volumetry Within the Hypoperfused Tissue: Technical Implementation and Evaluation
    imageObjective: The aim of this study was to develop a rapid and fully automatic infarct core and tissue at risk volumetry approach in acute ischemic stroke. Methods: We evaluated an algorithm in which segmentation was restricted to 1 hemisphere and the potential lesion characterized on the basis of the perfusion parameter Tmax with a region-wise comparison of local histograms to its mirrored counterpart. Results: We applied the “Tmax inside” method to 30 cases of a public data set with ground-truth segmentations for diffusion-weighted and perfusion magnetic resonance imaging. Lesions were robustly identified with significantly higher dice coefficients (apparent diffusion coefficient, 0.83 ± 0.22; Tmax, 0.80 ± 0.05, compared with 0.53 ± 0.27 and 0.56 ± 0.18) than for a global thresholding approach. Conclusions: The proposed “Tmax inside” method is superior to the commonly used global thresholding approach. Furthermore, the method allows evaluating changes in cerebral blood volume and blood flow by taking the counterpart in the healthy hemisphere as a patient-individual reference.



  4. Computed Tomography in the Management of Adrenal Tumors: Does Size Still Matter?
    imageObjective: We sought to evaluate computed tomography (CT) imaging as a predictor of adrenal tumor pathology. Methods: A retrospective review was conducted of patients who underwent unilateral adrenalectomy for an adrenal mass between January 2005 and July 2015. Tumors were classified as benign, indeterminate, or malignant based on preoperative CT findings. Results: Of 697 patients who underwent unilateral adrenalectomy, 216 met the inclusion criteria. Pathology was benign in 88.4%, indeterminate in 2.3%, and malignant in 9.3%, with a median tumor diameter of 2.7 cm (interquartile range, 1.7–4.1 cm) and 9.5 cm (interquartile range, 7.1–12 cm) in the benign and malignant groups, respectively (P < 0.001). Of the tumors with benign features on CT, 100% (143/143) had benign final pathology. Conclusions: Imaging characteristics of adrenal tumors on CT scan predict benign pathology 100% of the time. Regardless of size, when interpreted as benign on CT scan, laparoscopic adrenalectomy, if technically feasible, should be the technique used when surgery is offered, or close surveillance may be a safe alternative.



  5. Computed Tomography in the Diagnosis of Classical Trigeminal Neuralgia
    imageObjective: This study aims to characterize the pathogenesis of neurovascular conflict in trigeminal neuralgia (TN) with the goal of producing a reliable diagnostic method. Methods: Data were obtained during microvascular decompression surgery. The normal relationship between the superior cerebellar artery (SCA) and the trigeminal nerve root also was characterized in postmortem cases. Furthermore, SCA was imaged with high-resolution computed tomography angiography. Results: Our results indicate that contact between SCA and the trigeminal nerve root is present in both TN and non-TN cases, but in patients with TN, the apex of SCA loop was always at the bottom of the upper edge of the trigeminal root forming the state of neurovascular conflict. High-resolution angiography supported the intraoperative results. Conclusions: These findings indicate a clear difference between neurovascular contact and conflict and point to the use of high-resolution computed tomography visualization of the position of SCA loop apex relative to the trigeminal nerve root as a primary diagnostic method.


  6. Hematocrit and Serum Hemoglobin Do Not Influence Values in Computed Tomography Perfusion of Patients With Acute Ischemic Stroke
    imageObjective: There is a correlation between both serum hemoglobin (HGB) and hematocrit (HCT) and attenuation values of vessels in noncontrast-enhanced computed tomography (NECT), which could influence calculated perfusion maps in CT perfusion. Methods: We retrospectively included 45 patients, who presented with acute new neurological symptoms and underwent NECT and CT perfusion (128-row multi detector scanner, coverage: 6.9 cm craniocaudally; 80 kV; 200 mAs; temporal resolution: 2 seconds using 40 mL Ultravist 370 at a flow rate of 5 mL/s) on admission and a follow-up MRI within 1 week of admission. Results: Hematocrit, HGB, and attenuation values did not differ between patients with stroke and controls. A statistically significant correlation was found between HCT and HGB and attenuation values in the internal carotid artery or middle cerebral artery on NECT (P < 0.05). No statistically significant correlation was observed between HCT and HGB and perfusion maps. Conclusions: Hematocrit and HGB do not influence calculated perfusion maps. There is no need for HCT/HGB-adjusted cerebral blood volume thresholds in stroke patients.



  7. Median Lingual Lymph Nodes: Prevalence on Imaging and Potential Implications for Oral Cavity Cancer Staging
    imageObjective: This study sought to estimate the prevalence of median lingual lymph node (MLLN) metastases from oral cavity squamous cell carcinoma (OCSCC) and determine the frequency with which MLLNs can be identified with magnetic resonance imaging (MRI) in control subjects. Methods: Pathology reports were used to identify patients with surgically treated OCSCC who underwent preoperative positron emission tomography–computed tomography to define the prevalence of MLLN metastases. As a control group, 500 consecutive face-neck MRIs from noncancer patients were reviewed for structures consistent with MLLNs. Results: In the study group, 1 (0.95%) of 105 OCSCC cases demonstrated a single MLLN metastasis from a lateral tongue tumor (T4aN2c). The MLLN exceeded 1 cm in all planes and was abnormal in morphology. The frequency of suspected MLLNs in controls was 1.0%, with a maximum measurement of 0.9 cm. Conclusions: Median lingual lymph nodes are infrequently identified with MRI in controls, concordant with the low prevalence of metastases from OCSCC to this inconstant nodal group.



  8. Digital Subtraction of Magnetic Resonance Images Improves Detection and Characterization of Pancreatic Neuroendocrine Neoplasms
    imageObjective: The aim of this study was to evaluate the usefulness of digital image subtraction of contrast-enhanced magnetic resonance (MR) images for detection and characterization of pancreatic neuroendocrine neoplasms (PanNENs). Methods: Magnetic resonance examinations of 50 histologically verified PanNENs were retrospectively evaluated by 2 radiologists; 50 ductal adenocarcinomas were included as a control group. Late arterial phase images and correspondent subtracted images were analyzed. Tumor detectability on a subjective 3-point scale and contrast-to-noise ratios were compared across sequences using paired Student t tests. Tumor signal intensity was compared between sequences using χ2 or Fisher exact tests. Results: Subjective conspicuity and contrast-to-noise ratios of PanNENs were significantly higher on subtracted images compared with correspondent late arterial phase images (P < 0.001 and P = 0.002). The rate of clearly hyperenhancing PanNENs was higher on subtracted images compared with arterial phase images (76% vs 36%). Conclusions: Digital image subtraction improves tumor conspicuity and allows better characterization of PanNENs compared with late arterial phase images.



  9. Bifid Mandibular Canals Incidence and Anatomical Variations in the Population of Shanghai Area by Cone Beam Computed Tomography
    imageObjective: The aim of this study was to analyze the rate, location, and characteristics of bifid mandibular canals (BMCs) in the population of the Shanghai area using cone beam computed tomography to avoid complications during surgical procedures. Methods: Two hundred eighty patients were recruited for this study, and the presence and morphology of BMCs were evaluated. Results: The occurrence rate of BMCs in the Shanghai area was relatively high compared with that in other populations, reaching 31.1%. In addition, the study also found some far less-common trifid mandibular canals, as well as a peculiarly shaped special type, which we called v-type canal that has yet to be described. Conclusions: Our study underlined the different characteristics and occurrence rates of BMCs in the population of the Shanghai area and the importance of using cone beam computed tomography for a reliable detection, providing useful information to help prevent presurgery and postsurgery complications.



  10. Comparison of the Timing of Hepatic Arterial Phase and Image Quality Using Test-Bolus and Bolus-Tracking Techniques in Gadolinium–Ethoxybenzyl–Diethylenetriamine Pentaacetic Acid–Enhanced Hepatic Dynamic Magnetic Resonance Imaging
    imageObjectives: The aim of this study was to compare the image quality, the degree of artifacts and the percentage of timing of the optimal hepatic arterial phase (HAP) between test-bolus and bolus-tracking methods on gadolinium–ethoxybenzyl–diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)–enhanced magnetic resonance imaging (MRI). Methods: In this prospective study, 60 patients who underwent 3-dimensional dynamic Gd-EOB-DTPA–enhanced hepatic 3-T MRI were enrolled in this study. We randomly assigned the 30 patients to the bolus-tracking method, and another 30 patients to the test-bolus method. Signal-to-noise ratios of the liver and spleen in HAP were compared in the 2 groups. Two radiologists independently assessed the ratio of optimal timing of HAP and the degree of ringing and motion artifacts of the 2 protocols. Results: The signal-to-noise ratios of the liver (24.0 [SD, 6.4] vs 20.4 [SD, 4.0]) and spleen (30.0 [SD, 13.3] vs 23.6 [SD, 9.9]) were significantly higher in the test-bolus protocol than in the bolus-tracking protocol. The ratio of optimal timing was also significantly higher with the test-bolus protocol than with the bolus-tracking protocol (76.7% vs 40.0%). The degree of ringing and motion artifacts of test-bolus protocol was significantly lower than that of the bolus-tracking protocol (P < 0.01). Conclusions: The test-bolus protocol in dynamic 3-T MRI can yield better qualitative image quality and more optimal timing of HAP images, while reducing the degree of artifacts compared with the bolus-tracking protocol.


  11. Magnetic Resonance Imaging of Parotid Gland Tumors: Dynamic Contrast-Enhanced Sequence Evaluation
    imageObjective: The aim of the study was to evaluate dynamic contrast-enhanced magnetic resonance (MR) imaging in the characterization of parotid gland tumors. Methods: Fifty-five parotid lesions in 55 patients were retrospectively included. Two observers interpreted 2 reading protocols derived from all MR imaging in 2 distinct sessions, independently and blinded. Benign versus malignant distinction was carried out for protocol 1 (without contrast administration) and protocol 2 (with dynamic contrast-enhanced sequence). Histopathological results after surgical resection were used as the criterion standard. Diagnostic accuracy was compared between protocols using McNemar test. A P values of less than 0.05 indicated significant difference. Results: There was no intraobserver statistical discordance between protocols for both observers (P = 0.27 and P = 1). Interobserver reliability showed moderate agreement for protocol 1 (κ = 0.591; 95% confidence interval [CI], 0.376–0.806) and 2 (κ = 0.463, 95% CI, 0.226–0.701). Intraobserver reliability showed moderate agreement for observer 1 (κ = 0.507; 95% CI, 0.279–0.736) and 2 (κ = 0.477; 95% CI, 0.241–0.712). Conclusions: Magnetic resonance imaging protocol including dynamic sequence for the characterization of parotid gland lesion yielded nonsignificant increases in sensitivity, specificity, or positive predictive values, and negative predictive values over noninjected protocol.



  12. Improved Discrimination of Myocardial Perfusion Defects at Low Energy Levels Using Virtual Monochromatic Imaging
    imageObjectives: The aim of this study was to explore the diagnostic performance of dual-energy computed tomography perfusion (DE-CTP) at different energy levels. Methods: Patients with known or suspected coronary artery disease underwent stress and rest DE-CTP and single-photon emission computed tomography. Images were evaluated using monochromatic data, and perfusion defects were initially identified in a qualitative manner and subsequently confirmed using attenuation levels. Results: Thirty-six patients were included. Sensitivity, specificity, positive predictive value, and negative predictive value of DE-CTP for the identification of perfusion defects were 84.1%, 94.2%, 77.3%, and 96.2%, respectively. Perfusion defects showed significantly lower attenuation than normal segments, with the largest differences among low energy levels (sensitivity of 96% and specificity of 98% using a cutoff value ≤ 153 Hounsfield units at 40 keV), progressively declining at the higher levels (P < 0.001). Conclusions: Dual-energy CTP at the lowest energy levels allowed improved discrimination of perfusion defects compared with higher energy levels.



  13. Added Value of Parotid R2* Values for Evaluation of Sjögren Syndrome: A Preliminary Study
    imageObjective: To explore the application of parotid R2* values for evaluating Sjögren syndrome (SS). Methods: Twenty-four consecutive SS patients and 24 sex-matched and age-matched healthy volunteers underwent bilateral parotid 3.0 T magnetic resonance (MR) imaging, including blood oxygenation level dependent sequence. Parotid R2* values of SS patients and volunteers were compared. A receiver operating characteristic analysis was used to evaluate the diagnostic performance of parotid R2* value alone and in combination with MR nodular grade. Results: The left parotid R2* value was significantly lower than the right (P = 0.006) in SS patients. Parotid R2* value in SS patients was significantly lower than that in healthy volunteers (P < 0.001). With a cutoff value of 64.14/s, the sensitivity of the parotid R2* value was 62.5% in the diagnosis of SS. By combining R2* value with MR nodular grade, the sensitivity reached 87.5%. Conclusions: Parotid R2* value contributed to the diagnosis of Sjögren syndrome combined with MR nodular grade.



  14. Intravoxel Incoherent Motion Diffusion-Weighted Magnetic Resonance Imaging of Cervical Cancer With Different b-Values
    imageObjective: The aims of this study were to evaluate the dependence of diffusion parameters on the b values adopted for intravoxel incoherent motion diffusion-weighted magnetic resonance imaging and to investigate the application value of multiple diffusion parameters obtained from monoexponential and biexponential models in subjects with a normal cervix and in cervical cancer patients. Methods: A total of 120 female patients with cervical cancer and 21 female control subjects with a normal cervix underwent diffusion-weighted magnetic resonance imaging with 13 b values (0–2000 s/mm2) at 3 T. The standard apparent diffusion coefficient (Dst), diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (f) were calculated by fitting with monoexponential and biexponential models at 2 different ranges of b values: 0 to 1000 and 0 to 2000 s/mm2. A univariate analysis was performed to identify factors that could distinguish cervical carcinoma from normal cervical tissue. Parameters that correlated with the pathological grade and stage of cervical cancer were also evaluated. Receiver operating characteristic curves were used to evaluate the diagnostic efficiency of every parameter. Results: All the tested parameters, except the D* of the 2 different ranges of b value groups, significantly differed between the patients with cervical carcinoma and control subjects (P < 0.01). D2000, Dst2000, and D1000 showed comparable diagnostic value, with an area under the curve of 0.923, 0.909, and 0.907, respectively. Dst2000, D2000, Dst1000, and D1000 differed significantly among the 3 degrees of cervical stromal infiltration depth (P < 0.05). Conclusions: D2000 and Dst2000 tended to outperform D1000 in terms of diagnostic efficiency, but there was no significant difference in their ability to differentiate cervical carcinoma from normal cervix. Cervical cancers with lower Dst and D values tended to have greater infiltration depth.



  15. Detection of Bone Marrow Edema Pattern With Dual-Energy Computed Tomography of the Pig Mandible Treated With Radiotherapy and Surgery Compared With Magnetic Resonance Imaging
    imageObjective: The aim of the study was to investigate the accuracy of dual-energy computed tomography (DECT) compared with magnetic resonance (MR) imaging for the detection of edema of the mandible. Materials and methods: Fifteen adult Göttingen mini pigs received irradiation to the mandible with an equivalent dose of 0, 25, 50, or 70 Gy. Six months after irradiation, all animals underwent DECT and MR imaging of the mandible. Magnetic resonance short tau inversion recovery (STIR) was used for the grading of the bone marrow edema (0–3). Dual-energy CT (80 and 140 kVp) was performed, and virtual noncalcium (VNCa) images were calculated. Results: Increased signal intensity at STIR was found in the higher radiation groups. An increase of signal intensity in MR imaging was accompanied by a significant increase in the Hounsfield unit value of the VNCa images of the bone marrow (STIR: 0, 1, 2, 3; mean Hounsfield unit: −103, −90, −76, −34, respectively; P < 0.05; R2 = 0.388). Conclusions: The VNCa images derived from DECT are able to demonstrate bone marrow edema in radiation-induced bone changes in the mandible.


  16. Radiofrequency Ablation of Hepatic Tumor: Subjective Assessment of the Perilesional Vascular Network on Contrast-Enhanced Computed Tomography Before and After Ablation Can Reliably Predict the Risk of Local Recurrence
    imageObjective: To determine whether simple, subjective analysis of the perilesional vascular network can predict the risk of local recurrence after radiofrequency ablation (RFA) of liver malignancies on contrast-enhanced computed tomography (CECT). Methods: Contrast-enhanced computed tomography's 103 patients (59 men and 44 women; mean age, 63 years (range, 31–84 years) with 134 lesions who underwent RFA between 2000 and 2010 were retrospectively analyzed. The primary tumors include colorectal carcinoma (58 patients), hepatocellular carcinoma (n = 13), breast carcinoma (n = 8), neuroendocrine tumor (n = 5), and others (n = 19). Three blinded radiologists independently reviewed the CECT (a triple phase liver protocol for hypervascular tumors and a single phase for the hypovascular tumors) before and 6 weeks after RFA and subjectively estimated the width of the ablative margin on a 3-point scale (optimal, 1; suboptimal, 2; and residual tumor, 3). Local recurrence was determined on follow-up CECT. Results: The consensus score was 1 in 94, 2 in 28, and 3 in 12 lesions. κ among readers was 0.75. Local recurrence occurred in 3 lesions with a score of 1 and 12 lesions with a score of 2. The consensus score was a significant univariate predictor of local recurrence. Conclusions: Subjective estimation of the width of ablative margin can reliably predict the risk of local recurrence.



  17. Reassessing the Anatomic Origin of the Juvenile Nasopharyngeal Angiofibroma
    imageObjective: A modern imaging review is necessary to further define the anatomic origin of the juvenile nasopharyngeal angiofibroma. Methods: After institutional review board approval, a search from January 1998 to January 2013 yielded 33 male patients (aged 10–23 years) with pathologically proven juvenile nasopharyngeal angiofibroma lesions, as well as pretreatment computed tomography/magnetic resonance imaging. Juvenile nasopharyngeal angiofibroma involvement was assessed in the following regions: sphenopalatine foramen, pterygopalatine fossa, vidian canal, nasopharynx, nasal cavity, sphenoid sinus, choana, pterygomaxillary fissure/masticator space, orbit, and sphenoid bone. Results: The choana and nasopharynx were involved in all 33 patients. In contrast, only 22 lesions involved the pterygopalatine fossa, 24 lesions involved the sphenopalatine foramen, and 28 lesions involved the vidian canal. Conclusions: Our results suggest that the juvenile nasopharyngeal angiofibroma origin is in the region of the choana and nasopharynx rather than the sphenopalatine foramen or pterygopalatine fossa.



  18. The Performance of Noncontrast Magnetic Resonance Angiography in Detecting Renal Artery Stenosis as Compared With Contrast Enhanced Magnetic Resonance Angiography Using Conventional Angiography as a Reference
    imageObjective: The aims of this study were to evaluate the performance of noncontrast magnetic resonance angiography (NC MRA) for detecting renal artery stenosis (RAS) as compared with contrast-enhanced magnetic resonance angiography (CE MRA) and to evaluate the clinical feasibility, technical success rate, and performance of NC MRA for detecting RAS as compared with CE MRA. Methods: Thirty-six subjects who underwent NC MRA and/or CE MRA were enrolled. Feasibility, technical success rate, and image quality scores were compared. Diagnostic ability was calculated using conventional angiography as a reference. Results: Noncontrast MRA had higher feasibility and technical success rates than CE MRA did (100% and 97.2% vs 83.3% and 90%, respectively). Noncontrast MRA yielded significantly better image quality in motion artifact (P = 0.016). The diagnostic ability for detecting RAS is without significant difference between NC MRA and CE MRA. Conclusion: Although NC MRA and CE MRA demonstrated comparable ability in diagnosing RAS, NC MRA achieved better technical success rates, feasibility, and image quality in motion artifacts than CE MRA did.



  19. Low-Energy Virtual Monochromatic Dual-Energy Computed Tomography Images for the Evaluation of Head and Neck Squamous Cell Carcinoma: A Study of Tumor Visibility Compared With Single-Energy Computed Tomography and User Acceptance
    imageObjective: Dual-energy computed tomography (CT) 40-keV virtual monochromatic images (VMIs) have been reported to improve visualization of head and neck squamous cell carcinoma, but a direct comparison to single-energy CT (SECT) is lacking, and there is debate regarding subjective user preference. We compared 40-keV VMIs with SECT and performed a subjective evaluation of their utility and acceptability for clinical use. Methods: A total of 60 dual-energy CT and 60 SECT scans from 2 different institutions were evaluated. Tumor conspicuity was evaluated objectively using absolute and relative attenuation and subjectively by 3 head and neck specialists and 3 general radiologists. Results: Tumors had significantly higher absolute and relative attenuation on 40-keV VMIs (P < 0.0001). Subjectively, the 40-keV VMIs improved visualization, with substantial (κ, 0.61–0.80) to almost perfect (κ, 0.81–1) interrater agreements. Conclusions: The 40-keV VMIs improve tumor visibility objectively and subjectively both by head and neck specialists and general radiologists.



  20. Torsed and Nontorsed Inguinal Undescended Testis: Comparison of Computed Tomography Findings
    imageObjective: The aim of this study was to compare the computed tomography imaging features of a torsed inguinal testis with nontorsed inguinal testes. Methods: Computed tomography scans of patients with undescended testes were retrospectively collected (2011–2016). Imaging features of nontorsed undescended testis were compared with a case of an inguinal torsed testis. Observations included location of the undescended testis, size (length × width) and texture of each testis, peritesticular findings, position of testicular vessels, and enhancement patterns. Results: Twelve nontorsed inguinal undescended testes were compared with 1 torsed undescended testicle. Torsed testis was larger than nontorsed (44 × 27 mm vs 32.9 ± 6.1 × 22.9 ± 4.9 mm), surrounded by fat stranding and fluid, with heterogeneous texture, enhancement of its outer layers, and an upward kink of its vessels. Conclusions: Because torsed undescended testis can mimic a groin abscess and because torsion is a medical emergency, radiologists should be aware of this entity and its distinguishing imaging features. Color Doppler examination can ascertain absence/reduction of blood flow.


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