Quantitative evaluation of calcaneofibular ligament injury on the oblique coronal view of magnetic resonance imaging in chronic lateral ankle instability.

BACKGROUND: In the treatment of chronic lateral ankle instability (CLAI), the repair of the calcaneofibular ligament (CFL) and anterior talofibular ligament (ATFL) is still being discussed, possibly due to the difficulty in assessing CFL injuries. In particular, it is challenging to evaluate the extent of CFL deficiency quantitively. We hypothesized that CFL tension change would alter morphology of the CFL on magnetic resonance imaging (MRI) and that measuring this morphological change allows assessing CFL injury quantitatively. Thus, this study aimed to analyze the feasibility of quantitatively assessing CFL injuries using MRI. METHODS: Sixty-four ankles with CLAI were included and divided into two groups: with (ATFL and CFL group, 31 ankles) or without CFL repair (ATFL group, 33 ankles) in addition to arthroscopic ATFL repair. The angle between the CFL and calcaneal axis (CFLCA) and the bending angles of the CFL was defined as the flexed CFL angle (FCA) were measured on the oblique CFL view of preoperative MRI. The diagnostic abilities of these angles for CFL injury and correlations between these angles and stress radiographs were analyzed. RESULTS: The sensitivity and specificity of CFLCA were 86.7 % and 88.7 %, and those of FCA were 63.3 % and 77.4 %, respectively. The combination of CFLCA and FCA improved the sensitivity to 93.3 %. The cutoff points of CFLCA and FCA were 3.8° and 121.2°, respectively. There were significant moderate and weak correlations between the talar tilting angle and CFLCA or FCA (rs = -0.533, and rs = -0.402, respectively). The CFLCA and FCA were significantly smaller in the ATFL and CFL group than those in the other groups. CONCLUSIONS: Measurement of CFLCA and FCA in oblique CFL view on MRI could be useful for the quantitative evaluation of CFL injury in patients with CLAI． LEVEL OF EVIDENCE: Level IV. case-control study.

Telepathology in intraoperative frozen section consultation of breast cancer sentinel node biopsy in Fukushima, Japan following the 2011 triple disaster: diagnostic accuracy and required time during the early implementation phase.

In breast cancer surgery, some medical facilities lack the necessary resources to conduct sentinel lymph node biopsy and its intraoperative frozen section consultation. In the coastal rural area of Fukushima, Japan, which has suffered from physician undersupply following the 2011 triple disaster of earthquake, tsunami and nuclear disaster, we explored the feasibility of telepathology by evaluating the diagnostic accuracy in remote intraoperative frozen section consultation of sentinel lymph node biopsy and its required time. Although examination time has room for improvement, telepathology can be one possible solution in resource-limited areas.

Differentiation of Kawasaki Disease From Other Causes of Fever and Cervical Lymphadenopathy: A Diagnostic Scoring System Using Contrast-Enhanced CT.

OBJECTIVE: The purpose of this study is to determine the characteristic findings of contrast-enhanced CT (CECT) of the neck in patients with Kawasaki disease (KD) and to develop a diagnostic scoring system to facilitate the diagnosis of KD versus other causes of fever and cervical lymphadenopathy. MATERIALS AND METHODS: Two blinded radiologists evaluated CECT images of 37 patients with KD and 92 patients without KD who had febrile cervical lymphadenopathy, first independently and then in consensus. Significant findings in CECT images were evaluated through cervical edema and lymph node scores. CT attenuation of the nodal low-attenuation area and its ratio to the CT attenuation of the trapezius muscle were measured. On the basis of these indexes, a diagnostic scoring system was developed to differentiate between patients with and without KD. Its diagnostic performance was determined using ROC curve analysis. RESULTS: Retropharyngeal edema, lateral cervical edema, nasopharyngeal wall edema, level IIA lymphadenopathy, and retropharyngeal lymphadenopathy were more common in patients with KD than in patients without KD (p < 0.001, < 0.001, < 0.001, 0.003, and 0.028, respectively). Level VB lymphadenopathy was more common in patients without KD (p = 0.013), and the presence of nodal low-attenuation areas with lower attenuation indexes (attenuation of nodal low-attenuation area ≤ 50 HU, or ratio of attenuation of nodal low-attenuation area to trapezius muscle attenuation ≤ 0.7) was specific to patients without KD. In cases of higher attenuation indexes and cervical edema and lymph node scores of 4 or higher, sensitivity, specificity, and accuracy of the diagnostic scoring system were 86% (32/37), 86% (79/92), and 86% (111/129), respectively, for diagnosing KD. CONCLUSION: The proposed diagnostic scoring system was useful in differentiating between patients with and without KD.

Subjective and objective image quality of low-dose CT images processed using a self-supervised denoising algorithm.

This study aimed to assess the subjective and objective image quality of low-dose computed tomography (CT) images processed using a self-supervised denoising algorithm with deep learning. We trained the self-supervised denoising model using low-dose CT images of 40 patients and applied this model to CT images of another 30 patients. Image quality, in terms of noise and edge sharpness, was rated on a 5-point scale by two radiologists. The coefficient of variation, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR) were calculated. The values for the self-supervised denoising model were compared with those for the original low-dose CT images and CT images processed using other conventional denoising algorithms (non-local means, block-matching and 3D filtering, and total variation minimization-based algorithms). The mean (standard deviation) scores of local and overall noise levels for the self-supervised denoising algorithm were 3.90 (0.40) and 3.93 (0.51), respectively, outperforming the original image and other algorithms. Similarly, the mean scores of local and overall edge sharpness for the self-supervised denoising algorithm were 3.90 (0.40) and 3.75 (0.47), respectively, surpassing the scores of the original image and other algorithms. The CNR and SNR for the self-supervised denoising algorithm were higher than those for the original images but slightly lower than those for the other algorithms. Our findings indicate the potential clinical applicability of the self-supervised denoising algorithm for low-dose CT images in clinical settings.

Assistive AI in Lung Cancer Screening: A Retrospective Multinational Study in the United States and Japan.

Purpose To evaluate the impact of an artificial intelligence (AI) assistant for lung cancer screening on multinational clinical workflows. Materials and Methods An AI assistant for lung cancer screening was evaluated on two retrospective randomized multireader multicase studies where 627 (141 cancer-positive cases) low-dose chest CT cases were each read twice (with and without AI assistance) by experienced thoracic radiologists (six U.S.-based or six Japan-based radiologists), resulting in a total of 7524 interpretations. Positive cases were defined as those within 2 years before a pathology-confirmed lung cancer diagnosis. Negative cases were defined as those without any subsequent cancer diagnosis for at least 2 years and were enriched for a spectrum of diverse nodules. The studies measured the readers' level of suspicion (on a 0-100 scale), country-specific screening system scoring categories, and management recommendations. Evaluation metrics included the area under the receiver operating characteristic curve (AUC) for level of suspicion and sensitivity and specificity of recall recommendations. Results With AI assistance, the radiologists' AUC increased by 0.023 (0.70 to 0.72; P = .02) for the U.S. study and by 0.023 (0.93 to 0.96; P = .18) for the Japan study. Scoring system specificity for actionable findings increased 5.5% (57% to 63%; P < .001) for the U.S. study and 6.7% (23% to 30%; P < .001) for the Japan study. There was no evidence of a difference in corresponding sensitivity between unassisted and AI-assisted reads for the U.S. (67.3% to 67.5%; P = .88) and Japan (98% to 100%; P > .99) studies. Corresponding stand-alone AI AUC system performance was 0.75 (95% CI: 0.70, 0.81) and 0.88 (95% CI: 0.78, 0.97) for the U.S.- and Japan-based datasets, respectively. Conclusion The concurrent AI interface improved lung cancer screening specificity in both U.S.- and Japan-based reader studies, meriting further study in additional international screening environments. Keywords: Assistive Artificial Intelligence, Lung Cancer Screening, CT Supplemental material is available for this article. Published under a CC BY 4.0 license.

Unique Anatomical Features of the Discoid Lateral Meniscus via Three-Dimensional MRI.

Background The discoid lateral meniscus (DLM) is a unique anatomical variant characterized by a larger, thicker lateral meniscus. For clinical diagnosis of DLM, coronal and sagittal slices in two-dimensional (2D) MRI and arthroscopic imaging are typically employed. However, evaluating the entire shape of the DLM is challenging due to the limited views and details provided by these methods. Three-dimensional (3D) visualization with MRI offers a more comprehensive view of the entire meniscus. The purpose of this study was to demonstrate the entire shape of a DLM using 3D images and unveil its unique characteristics. Methods The study population consisted of 31 knees diagnosed with DLM through arthroscopic examination at our hospital between 2017 and 2021. This group comprised 20 males (65%) and 11 females (35%), with ages ranging from 9 to 49 years (mean age, 24.2 years). Furthermore, a control group of 43 knees without DLM was included for comparative analysis. This control group consisted of 22 males (51%) and 21 females (49%), with ages ranging from 9 to 69 years (mean age, 28.5 years). 3D images of the medial meniscus (MM) and lateral meniscus (LM) were reconstructed from 1.5T-MRI images with semi-automatic segmentation using free software. From the coordinate information, the anterior-to-posterior lengths of the MM and LM were obtained, and the medial-to-lateral anterior-to-posterior length (L/M ratio) ratio was calculated and compared with the value of the non-DLM population. Results Our method allows for the detailed delineation of the DLM's unique morphology. The DLM group exhibited a significantly smaller L/M ratio compared to the non-DLM group (DLM: 0.66±0.06, non-DLM: 0.74±0.05, p<0.001). Conclusions Reconstructed 3D images could help to demonstrate the whole morphology of DLM and reveal its unique features, in which DLM shows a significantly smaller L/M ratio as compared to non-DLM.

New technique of percutaneous CT fluoroscopy-guided marking before video-assisted thoracoscopic surgery for small lung lesions: feasibility of using a 25-gauge needle without local anaesthesia.

OBJECTIVE: To retrospectively evaluate the feasibility of CT fluoroscopy-guided percutaneous marking using a 25-gauge needle and indigo carmine before video-assisted thoracoscopic surgery (VATS) for small lung lesions. METHODS: 21 patients, 14 males and 7 females, with a median age of 69 years (range, 40-79), underwent CT fluoroscopy-guided percutaneous VATS marking using a 25-gauge, 70-mm needle and 1.5-ml indigo carmine. The mean diameter of the lung lesions was 14 mm (range, 6-27). We evaluated the technical success rate, surgical success rate and complications related to this procedure by reviewing medical records and images. Technical success was defined as completion of this procedure. Surgical success was defined as resection of the target lesion with negative margins on pathological examination after VATS. Complications that required advanced levels of care were classified as major complications, and the remaining complications were considered minor. RESULTS: The technical success rate was 100%. In all cases, VATS was successfully performed as planned, and the target lesion was resected with negative margins on pathological examination after VATS. Thus, the surgical success rate was 100%. Mild pneumothorax was found in two cases, but further treatment was not required. The minor complication rate was 9.5% (2/21), and major complication rate was 0%. Only two patients (9.5%) complained of slight pain upon puncture, but local anaesthesia was not required. CONCLUSION: Percutaneous CT fluoroscopy-guided VATS marking using a 25-gauge needle without local anaesthesia appears feasible and safe. Advances in knowledge: This technique expands a possibility of the CT-guided marking.

Advantages of an on-the-screwhead crosslink connector for atlantoaxial fixation using the Goel/Harms technique.

The goal of fixation surgery for atlantoaxial instability is to achieve solid bony fusion. Achieving bony fusion as early as possible is beneficial for patients. Although placement of a transverse cross-link connector (XL) provides greater biomechanical strength, XLs have not been able to be placed when performing the Goel/Harms procedure. Recently, placing a XL on the screw head (on-the-head XL [OH-XL]) has become a viable option during the Goel/Harms procedure. However, there is little evidence demonstrating whether applying an OH-XL achieves early solid bony union. A matched-control study was conducted to investigate whether placing an OH-XLs in C1/2 fixation surgery provides earlier bone union or not. Eighteen patients who underwent atlantoaxial fusion with OH-XLs (X-group), and 17 age and sex-matched patients without OH-XLs (NX-group) were compared. Bony union was assessed using reconstructed sagittal and coronal computed tomography images. Six months after surgery, six patients in the X-group and one patient in the NX-group achieved bony union (p = .0338). One year after surgery, 14 patients in the X-group and 4 patients in the NX-group achieved bone union (p = .0010). Two years after surgery, 17 patients in the X-group and 9 patients in the NX-group achieved bony union (p = .0011). This is the first report of the clinical application of OH-XLs for the Goel/Harms procedure. OH-XLs yield earlier bony fusion; thus, placing OH-XLs is beneficial for atlantoaxial fixation surgery using lateral mass screws of the atlas.