Journal of Computer Assisted Tomography最新文献

Objective: The aim of the study is to assess the validity of a recently published consensus magnetic resonance imaging (MRI) diagnostic algorithm for differentiating degenerating leiomyomas from uterine sarcomas and other atypical appearing uterine malignancies.

Methods: Atypical uterine masses on pelvic MRI were identified using a radiology report search engine and teaching files with the keywords "atypical leiomyoma," "atypical fibroid," and "sarcoma." All cases were pathology-proven. Two radiologists blinded to clinical, surgical, and pathologic reports retrospectively and independently reviewed 40 pelvic MRI examinations dated 1/2007-9/2022 to determine whether the masses appeared benign or malignant, using the 2022 consensus atypical uterine mass flow chart. Imaging features assessed included intermediate/high signal intensity (SI) at T2-weighted imaging, high diffusion weighted imaging SI (equal or higher SI than endometrium or lymph nodes on high b value imaging), apparent diffusion coefficient (ADC) value ≤0.905 × 10-3 mm2/s, peritoneal metastases, and abnormal lymph nodes.

Results: Among the 40 atypical uterine mass cases reviewed, 24 masses were benign (22 leiomyomas, 1 adenomyoma, and 1 borderline ovarian tumor) and 16 masses were malignant (6 leiomyosarcomas, 6 carcinosarcomas, 2 endometrial stromal sarcomas, 1 high-grade adenosarcoma, and 1 low-grade uterine sarcoma). Sensitivity, specificity, positive predictive value, and negative predictive value of whether a mass was benign or malignant were 75%, 95.8%, 92.3%, and 85% for reader 1, and 81.2%, 91.7%, 86.7%, and 88% for reader 2, respectively. Interrater agreement was strong, with a kappa statistic of 0.89. When excluding nonleiomyosarcoma uterine malignancies, sensitivity and negative predictive value improved to 100%.

Conclusions: The new consensus pelvic MRI algorithm for evaluating atypical uterine masses has good specificity, sensitivity, positive predictive value, and negative predictive value for determining malignancy, particularly for uterine sarcomas that are leiomyosarcomas. However, if ADC value is near but not below 0.905 × 10-3 mm2/s, the mass may still be malignant, especially if a b value lower than 1000 is used. If the atypical uterine mass is predominantly endometrial, morphological features on T2 and postgadolinium sequences should guide suspicion, as some atypical appearing nonleiomyosarcoma uterine malignancies may have an ADC value greater than 0.905 × 10-3 mm2/s.

Objectives: To compare the image quality and radiation dose in coronary computed tomography angiography (CCTA) based on different acquisition time windows corresponding to the heart rate of breath-holding after free breathing.

Methods: Two hundred patients who underwent CCTA with a basal heart rate between 70 and 85 beats/min were divided into groups A and B, with 100 patients in each group. Patients in groups A and B were scanned with the acquisition time window corresponding to the heart rate determined during a breath hold obtained after free breathing and the basal heart rate during free breathing, respectively. Computed tomography (CT) attenuation values of the coronary artery, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were calculated. The subjective image scores of the groups were assessed blindly by 2 experienced physicians using a 4-point system, and score consistency was compared using the κ test. The volume CT dose index and dose-length product were recorded for each patient, and the effective dose (ED) was calculated. The Kruskal-Wallis H test was performed to evaluate differences in age, heart rate, and body mass index. A χ2 test was used to evaluate sex differences. An independent-sample t test was employed to compare objective and subjective data such as dose-length product, volume CT dose index, ED, SNR, CNR, and averaged subjective assessment scores. Statistical significance was set at P < 0.05.

Results: No statistically significant differences occurred in sex, age, or body mass index between patients in group A and group B (all P > 0.05). No significant differences occurred in the mean CT values, mean SNR values, mean CNR values, or mean subjective scores of CCTA images between the patients in groups A and B (P > 0.05). The ED values of the patients in group A were 52.93% lower than those in group B (P < 0.001).

Conclusion: The radiation dose in CCTA examinations can be significantly reduced while maintaining image quality by narrowing the acquisition time window for breath-holding after free breathing.

Objectives: We investigated volumetric changes in buccal fat pad (BFP) in age groups and sexes by cranial or neck computed tomography (CT) or cranial CT angiography.

Methods: One hundred twenty patients underwent cranial or neck CT examinations or cranial CT angiography were retrospectively screened: 18-29 years old (group 1), 30-49 years old (group 2), and 50 years and older (group 3). Left buccal fat tissue measurements were performed in age groups, sexes, and body mass index (BMI) groups.

Results: Left buccal fat volume in the 30-49 age group and the ≥50 age group was significantly higher than that in the 18-29 age group (P < 0.05). Across all groups and specifically within the 18-29 age group, females exhibited significantly lower buccal fat volume than males (P < 0.05). The left buccal fat volume of individuals classified as overweight and obese was significantly higher than that of the underweight and normal weight groups. There was a negative relationship between buccal fat volume and fat density. Moreover, as age increased, within age groups 1 to 3, there was a notable increase in body weight, body length, BMI, and BMI groups (underweight and normal weight to obesity), accompanied by a significant rise in buccal fat volume. Conversely, fat density exhibited a significant decrease with advancing age.

Conclusions: Buccal fat volume, localized in the middle third of the face, increased with aging and increasing BMI values. Young females had lower buccal fat volume. Buccal fat tissue volume is important in facial rejuvenation procedures such as facial filler applications.

Objective: To investigate the incremental value of pericoronary fat attenuation index (FAI) in routine coronary artery computed tomography angiography (CCTA) to identify culprit lesions in acute coronary syndrome (ACS).

Methods: We reviewed the CCTA data from 80 ACS patients and 40 individuals with stable coronary atherosclerosis. ACS patient plaques were categorized into culprit and nonculprit groups. The plaque-specific pericoronary FAI was assessed using the Perivascular Fat Analysis Tool. We applied a default prespecified window of -190 to -30 Hounsfield units (HU) and a broader prespecified window of -190 to 20 HU. FAI values within these prespecified windows and the types and severity of plaque stenosis were compared across the 3 groups. Additionally, we investigated high-risk characteristics of plaques in the ACS group and their correlation with FAI. The effectiveness and worthiness of FAI in identifying culprit lesions were analyzed based on the receiver operating characteristic curve.

Results: The FAI values under the 2 prespecified windows were higher in the culprit group than in the nonculprit and control groups (all P < 0.001). The culprit group showed the most mixed plaques and the most severe stenosis (all P < 0.001). In the ACS group, the FAI value was significantly lower around calcified lesions (-85.00 ± 9.97 HU) than around noncalcified (-78.00 ± 11.52 HU) and mixed plaques (-78.00 ± 9.24 HU) (both P < 0.001). The culprit group had more high-risk plaques, and high-risk plaques had higher FAI values than those without high-risk characteristics (-70.00 ± 7.67 HU vs -82.00 ± 10.16 HU, P < 0.001). The efficacy of FAI under the default prespecified window in identifying culprit lesions was higher compared than that under the broader prespecified window (area under the curve = 0.799 vs 0.761, P = 0.042), and the diagnostic cutoff values were -77 versus -58 HU. The FAI under the default prespecified window exhibited an incremental value for identifying culprit lesions, as compared with stenosis severity (area under the curve = 0.970 vs 0.939, P < 0.001).

Conclusion: The culprit lesions have higher FAI than the nonculprit lesions and the controls. FAI is a worthy parameter for identifying culprit lesions in routine CCTA according to stenosis severity, and the default prespecified window is a better option.

Background: Quantitative susceptibility mapping (QSM) is an emerging MRI technique with multiple clinical applications. As tissue susceptibility cannot be directly measured using MRI, QSM imaging techniques must indirectly compute susceptibility values, requiring regularization methods. CSF is a popular choice for regularization due to its near water susceptibility in healthy controls. However, the impact of pus, elevated protein, or blood dissolved in CSF on QSM regularization is not well defined.

Objective: This study aimed to investigate the effects of intracranial hemorrhage (ICH) on selecting CSF as reference for QSM imaging.

Materials and methods: A total of 87 subjects, 53 with ICH (5 intraventricular, 19 subarachnoid, 27 both, and 2 intraparenchymal only) and 37 without hemorrhage (27 with MS, 10 without MS), were included in this study. Imaging was performed using 3D multiecho gradient echo, FLAIR, and multiecho complex total field inversion (mcTFI) at 3 T. McTFI with and without CSF zero-referencing regularization was generated from the 3DMEGRE data and reviewed with FLAIR images. Regions of hemorrhagic (H+) and nonhemorrhagic (H-) CSF were manually selected in reference to head CT and FLAIR images by a PGY III diagnostic radiology resident and Certificate of Added Qualification-certified neuroradiologist with 10 years' experience. Paired Student t test and one-way ANOVA were used with post hoc multicomparisons. A P value <0.05 was considered statistically significant.

Results: Areas of H- CSF were noted to have higher regularized QSM values in subjects with ICH relative to subjects without. Unregularized H- QSM values were also noted to have a systematically higher value in ICH subjects relative to subjects without blood. Subjects with MS and without ICH did not show significant difference in H- CSF regularized or unregularized QSM values.

Conclusions: QSM values of areas suggested to not have hemorrhage on other imaging showed significantly higher QSM values in ICH subjects relative to subjects without ICH. Additionally, areas of hemorrhage did not show significant QSM value difference between regularized and unregularized QSM images. These findings suggest that, in subjects with any area of ICH, QSM values for no-hemorrhagic areas may be significantly altered using CSF regularization relative to subjects without ICH, with implications for intra- and intersubject QSM value analysis.

Objective: The aim of the study is to evaluate whether a pre-coronary artery bypass grafting (CABG) coronary computed tomography-based fractional flow reserve (FFR-CT) result at the site of a future anastomosis would predict the graft failure in patients undergoing CABG.

Methods: In 43 patients who had coronary computed tomography angiography (CCTA) prior to the CABG, follow-up CCTA were acquired >12 months post-CABG procedure. The FFR-CT values were simulated on the basis of the pre-CABG CCTA. Based on follow-up CCTA, the anastomosis sites and the graft patency were determined. The graft failure was defined as either its stenosis >50% or occlusion.

Results: Ninety eight (44 saphenous, 54 left or right internal mammary artery) grafts were assessed. Eighteen grafts from 16 patients were dysfunctional on follow-up CCTA. The FFR-CT values at the location of future anastomosis were higher in dysfunctional than in normal grafts (0.77 [0.71-0.81] vs 0.60 [0.56-0.66], respectively, P = 0.0007). Pre-CABG FFR-CT (hazard ratio = 1.1; 95% CI: 1.012-1.1, P = 0.0230), and bypass graft to right coronary artery (hazard ratio = 3.7; 95% CI: 1.4-9.3 vs left anterior descending artery) were independent predictors of graft dysfunction during follow-up. The optimal threshold of FFR-CT to predict graft failure was >0.68 (sensitivity 88.9% (95% CI: 65.3-98.6), specificity 63.7% (95% CI: 52.2-74.2), positive predictive value 35.6% (95% CI: 28.3%-43.5%), negative predictive value 96.2% (95% CI: 87.2%-99.0%)).

Conclusions: Pre-CABG functional FFR-CT predicts future coronary bypass graft failure. This shows utility of FFR-CT for guiding coronary revascularization and also suggests significance of physiological assessment prior to CABG.

Abstract: Mucinous rectal cancer (MRC) is defined by the World Health Organization as an adenocarcinoma with greater than 50% mucin content. Classic teaching suggests that it carries a poorer prognosis than conventional rectal adenocarcinoma. This poorer prognosis is thought to be related to mucin dissecting through tissue planes at a higher rate, thus increasing the stage of disease at presentation. Developments in immunotherapy have bridged much of this prognostic gap in recent years. Magnetic resonance imaging is the leading modality in assessing the locoregional spread of rectal cancer. Mucinous rectal cancer carries unique imaging challenges when using this modality. Much of the difficulty lies in the inherent increased T2-weighted signal of mucin on magnetic resonance imaging. This creates difficulty in differentiating mucin from the adjacent background fat, making the detection of both the primary disease process as well as the locoregional spread challenging. Computed tomography scan can act as a valuable companion modality as mucin tends to be more apparent in the background fat. After therapy, diagnostic challenges remain. Mucin is frequently present, and distinguishing cellular from acellular mucin can be difficult. In this article, we will discuss each of these challenges and present examples of such situations and strategies that can be used to overcome them.

Objective: The aim of this study was to assess the utility of the combined use of 3D wheel sampling and deep learning-based reconstruction (DLR) for intracranial high-resolution (HR)-time-of-flight (TOF)-magnetic resonance angiography (MRA) at 3 T.

Methods: This prospective study enrolled 20 patients who underwent head MRI at 3 T, including TOF-MRA. We used 3D wheel sampling called "fast 3D" and DLR for HR-TOF-MRA (spatial resolution, 0.39 × 0.59 × 0.5 mm 3 ) in addition to conventional MRA (spatial resolution, 0.39 × 0.89 × 1 mm 3 ). We compared contrast and contrast-to-noise ratio between the blood vessels (basilar artery and anterior cerebral artery) and brain parenchyma, full width at half maximum in the P3 segment of the posterior cerebral artery among 3 protocols. Two board-certified radiologists evaluated noise, contrast, sharpness, artifact, and overall image quality of 3 protocols.

Results: The contrast and contrast-to-noise ratio of fast 3D-HR-MRA with DLR are comparable or higher than those of conventional MRA and fast 3D-HR-MRA without DLR. The full width at half maximum was significantly lower in fast 3D-MRA with and without DLR than in conventional MRA ( P = 0.006, P < 0.001). In qualitative evaluation, fast 3D-MRA with DLR had significantly higher sharpness and overall image quality than conventional MRA and fast 3D-MRA without DLR (sharpness: P = 0.021, P = 0.001; overall image quality: P = 0.029, P < 0.001).

Conclusions: The combination of 3D wheel sampling and DLR can improve visualization of arteries in intracranial TOF-MRA.

Objectives: To evaluate current policies and practices regarding preparative fasting before contrast-enhanced computed tomography (CECT) and the knowledge and attitudes of radiology head nurses.

Methods: Radiology head nurses in 499 Chinese hospitals participated in an online survey on preparative fasting for CECT, which mainly included current departmental policies and practices and their knowledge and attitudes.

Results: Response rate was 89.8% (448/499). All surveyed hospitals established preparative fasting protocols, mainly based on guidelines for iodinated contrast media (ICM) usage (68.8%). For the nongastrointestinal CECT scan, the most frequent fasting duration for solid food, semiliquid diet, liquid diet, and clear liquids was 4 to 6 hours (215/422 [50.9%]), less than 6 hours (332/396 [83.8%]), less than 6 hours (275/320, 85.9%), and less than 6 hours (151/189 [79.9%]), respectively. Forty-six percent of the respondents confirmed that unnecessary excessive fasting existed in practice, and the related patient discomfort occurred in 60.3% of the hospitals, mainly manifested as hypoglycemia (86.7%). Expert consensus and guidelines for iodinated contrast media usage (75%) were the leading approach to gain knowledge about preparative fasting; 90.6% of the respondents believed that the clinical scenarios requiring preparative fasting were the upper abdominal examinations. A majority of respondents (72.1%) believed that the current preparative fasting policies needed improvement.

Conclusion: Preparative fasting policies varied among hospitals in terms of the fasting content and duration. Respondents' opinions differed on fasting requirements based on various CECT examination sites and patients. The latest guideline regarding no fasting before CECT has not been fully adopted. Further research is required to promote the transformation of guideline evidence.