A Modified Targetoid Feature Emphasizing Thin-Rim APHE to Improve the Diagnostic Performance of LI-RADS for Malignant Hepatic Tumors.

Objective: To identify imaging features that help distinguish between HCCs and non-HCC malignancies assigned to LI-RADS M (LR-M) and evaluate the diagnostic performance of a LI-RADS with targetoid criteria using thin-rim arterial phase hyperenhancement (APHE). Materials and Methods: This retrospective study included 381 patients (387 observations) at high-risk for HCC who underwent enhanced-MRI before surgery. Three radiologists reviewed images for LI-RADS categorization of hepatic observations. Univariate and multivariate analysis was conducted to determine reliable features to differentiate between HCC and non-HCC malignancies among the LR-M lesions. The thin-rim (<30%) APHE was defined based on the thickest thickness of rim APHE compared with the tumor radius, and a modified LI-RADS emphasizing thin-rim APHE as a specific feature of LR-M was established. We compared the diagnostic performance of modified LR-M and LI-RADS 5 (LR-5) with the conventional one. Results: Thin-rim APHE and targetoid diffusion-weighted imaging (DWI) were found as independent predictive factors of non-HCC malignancies, while enhancing capsule, thick-rim APHE and peripheral washout were noted as independent variables significantly associated with HCC of LR-M (P<0.05). The noticeable diagnostic performance of thin-rim APHE in distinguishing non-HCC malignancies from HCCs using the ROC curve. Emphasizing thin-rim APHE on targetoid features, the modified LR-M revealed significantly superior specificity and accuracy (89.4% vs 81.1%, P=0.004; and 87.9% vs 82.2%, P=0.027, respectively) while maintaining high sensitivity (82.2% vs 86.0%; P=0.529) compared with the LR-M. Meanwhile, the modified LR-5 achieved greater sensitivity and accuracy (88.6% vs 79.7%, P=0.004; and 85.8% vs 80.1%, P=0.036, respectively) for diagnosing HCC, without compromising specificity (78.3% vs.81.1%; P=0.608) compared with the LR-5. Conclusion: Thin-rim APHE may be the specific imaging feature for differentiating non-HCC malignancies from HCCs within LR-M. The modified targetoid criteria emphasizing thin-rim APHE can improve the diagnostic performance of LI-RADS for hepatic malignancies.

AI-assisted compressed sensing and parallel imaging sequences for MRI of patients with nasopharyngeal carcinoma: comparison of their capabilities in terms of examination time and image quality.

OBJECTIVE: To compare examination time and image quality between artificial intelligence (AI)-assisted compressed sensing (ACS) technique and parallel imaging (PI) technique in MRI of patients with nasopharyngeal carcinoma (NPC). METHODS: Sixty-six patients with pathologically confirmed NPC underwent nasopharynx and neck examination using a 3.0-T MRI system. Transverse T2-weighted fast spin-echo (FSE) sequence, transverse T1-weighted FSE sequence, post-contrast transverse T1-weighted FSE sequence, and post-contrast coronal T1-weighted FSE were obtained by both ACS and PI techniques, respectively. The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and duration of scanning of both sets of images analyzed by ACS and PI techniques were compared. The images from the ACS and PI techniques were scored for lesion detection, margin sharpness of lesions, artifacts, and overall image quality using the 5-point Likert scale. RESULTS: The examination time with ACS technique was significantly shorter than that with PI technique (p < 0.0001). The comparison of SNR and CNR showed that ACS technique was significantly superior with PI technique (p < 0.005). Qualitative image analysis showed that the scores of lesion detection, margin sharpness of lesions, artifacts, and overall image quality were higher in the ACS sequences than those in the PI sequences (p < 0.0001). Inter-observer agreement was evaluated for all qualitative indicators for each method, in which the results showed satisfactory-to-excellent agreement (p < 0.0001). CONCLUSION: Compared with the PI technique, the ACS technique for MR examination of NPC can not only shorten scanning time but also improve image quality. CLINICAL RELEVANCE STATEMENT: The artificial intelligence (AI)-assisted compressed sensing (ACS) technique shortens examination time for patients with nasopharyngeal carcinoma, while improving the image quality and examination success rate, which will benefit more patients. KEY POINTS: • Compared with the parallel imaging (PI) technique, the artificial intelligence (AI)-assisted compressed sensing (ACS) technique not only reduced examination time, but also improved image quality. • Artificial intelligence (AI)-assisted compressed sensing (ACS) pulls the state-of-the-art deep learning technique into the reconstruction procedure and helps find an optimal balance of imaging speed and image quality.

The risk factors of hemorrhage in stereotactic needle biopsy for brain lesions in a large cohort: 10 years of experience in a single center.

BACKGROUND: This study aimed to identify the risk factors for hemorrhage from a large cohort who underwent stereotactic needle biopsy for brain lesions at a single center over a 10-year period. METHODS: We performed a retrospective chart review of consecutive patients who underwent stereotactic biopsy at our institute between January 2010 and December 2019. Demographic characteristics and clinical variables were collected and analyzed to identify risk factors for postbiopsy hemorrhage using the chi-square test and univariable and multivariable logistic regression analyses. RESULTS: A total of 3196 patients were included in this study; of these, a histological diagnosis was eventually made for 2938 (91.93%) patients. Hemorrhage occurred in 149 (4.66%) patients, and symptomatic hemorrhage occurred in 46 (1.44%) patients. In multivariable logistic regression analyses, the presence of deep-seated lesions (OR 1.272, p = 0.035), concomitant edema and enhancement on MR imaging scans (OR 1.827, p = 0.002), intraoperative hypertension without a past history (OR 1.012, p = 0.024), and the presence of high-grade glioma (OR 0.306, p = 0.003) were identified as independent predictors of hemorrhage after biopsy. CONCLUSION: Stereotactic needle biopsy is a safe and effective way to obtain tissue from brain lesions for histological diagnosis. The presence of deep-seated lesions, concomitant edema, and enhancement on MR imaging scans and the presence of high-grade glioma are independent predictors of hemorrhage after stereotactic biopsy.

Imaging algorithm and multimodality evaluation of spinal osteoblastoma.

BACKGROUND: To analyze the features of CT, MRI and PET/CT and their diagnostic value for spinal osteoblastomas (OBs). METHODS: The radiological and clinical data of 21 patients with histopathologically-confirmed spinal OBs were analyzed retrospectively. RESULTS: Sixteen of the 21 cases were benign and 5 were aggressive OBs. Tumors were located in the lumbar (n = 11), cervical (n = 4), thoracic (n = 5), and sacral (n = 1) spinal regions. Nineteen cases were centered in the posterior elements of the spine, 13 of which extended into the vertebral body. Punctate or nodular calcifications were found in all cases on CT with a complete sclerotic rim (n = 12) or incomplete sclerotic rim (n = 8). The flare phenomenon (indicative of surrounding tissue inflammation) was found in 17/21 cases on CT, thin in 11 cases and thick in 6 cases, and in 19/19 cases on MRI, thin in 1 case and thick in 18 cases. On 18F-FDG PET/CT, all cases (8/8) were metabolically active with the SUVmax of 12.3-16.0; the flare sign was observed in 8 cases, including 7 cases of hypometabolism and 1 case of coexistence of hypermetabolism and hypometabolism. Based on CT, 3, 12, and 6 cases were classified as Enneking stage 1, 2 and 3, respectively. Of 19 cases with MRI, 1 and 18 cases were classified as Enneking stage 2 and 3, respectively. CONCLUSIONS: Spinal OB has multiple unique characteristic radiological features. Although a larger sample size is needed, combining CT, MRI and PET may be beneficial to optimize preoperative diagnosis and care of patients with OBs.