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Background: Recurrence is one of the most common complications following hallux valgus surgery. Moreover, hallux varus occurs in cases of overcorrection. We aimed to quantitatively measure, using radiographic examination, the dynamics of the soft tissues that act on deformities (recurrence of valgus and occurrence of varus) after the surgery. Methods: This retrospective single-institution study included 60 patients (98 feet) who underwent hallux valgus surgery between 2009 and 2018. According to radiographic findings of the foot under weightbearing conditions at postoperative month 1, we examined the tendons’ pathway and calculated the forces on the first metatarsophalangeal joint, which we termed the deformity force angle (DFA). We compared whether there was a significant difference in DFAs between the groups in which deformities occurred and those in which deformities did not occur after correction. In addition, the DFA was compared to known radiographic measurements of hallux valgus recurrence (hallux valgus angle, distal metatarsal articular angle, intermetatarsal angle, and sesamoid position) to assess association with recurrence. Results: We observed a significant difference in the DFA between patients with and without hallux valgus recurrence ( P < .001) and between those with and without hallux varus ( P < .001) based on standing radiographs taken at a minimum of 6 months postoperation. For predicting the deformities, the areas under the curve were 0.863 (hallux valgus recurrence) and 0.831 (hallux varus occurrence), respectively, which was greater than other factors evaluated. The DFA values greater than 9.5 degrees and less than 5.5 degrees were associated with the recurrence of valgus and occurrence of varus, respectively. Conclusion: In our study, DFA was associated with hallux valgus recurrence when it exceeded 9.5 degrees and hallux varus when it was less than 5.5 degrees. Moreover, in the hallux valgus surgery we performed, a DFA from 5.5 to 9.5 degrees appeared to be a “safe zone” for preventing early deformity after surgery. Level of Evidence: Level III, prognostic.

Purpose: Thisstudy aimed to identify predictors of the occurrence and severity of neurological symptoms in patients with metastatic spinal tumor who still had noneurological symptoms. Methods: We retrospectively examined patients with metastatic spinal tumor (regardless of tumor type) who visited the Department of Rehabilitation Medicine between 2017 and 2021. Using the patients’ magnetic resonance imaging and clinical data, weinvestigated whether epidural spinal cord compression (ESCC) scale, spinal instability neoplastic score (SINS), and pain character were related to the occurrence and severity of neurological symptoms within 1 year. Results: Of the 70 included patients, 40 showedneurological symptoms, and 30 did not. Multivariable analysis showed that ESCC (2 or 3) (P = 0.002), SINS (P = 0.007), and radiating pain (P = 0.015) were associated with neurological complications. None of the factors was associated with neurological symptom severity. Notably, neurological symptoms progressed rapidly in patients with high ESCC (P = 0.003). Conclusion: ESCC, SINS, and radiating pain were related to the occurrence of neurological symptoms, but not to severity. Only ESCC was associated with the rapid progression of neurological symptoms. This retrospective study provides useful insights in predicting a patient's functional prognosis and determining management using radiology and clinical data.

Background The latest International Myeloma Working Group (IMWG) guideline recommends low-dose whole-body (WB) computed tomography (CT) as the first-line imaging technique for the initial diagnosis of plasma cell disorders. Purpose To evaluate diagnostic performances of CT and diffusion-weighted imaging (DWI) as the first-line imaging modalities and assess misclassification rates obtained following the guideline. Material and Methods Two independent radiologists analyzed CT (acquired as PET/CT) and DWI (3-T; b-values = 50 and 900 s/mm2) of patients newly diagnosed with plasma cell disorder, categorizing the number of bone lesions. Diagnostic performance of CT and DWI was compared using the McNemar test, and misclassification rates were calculated with a consensus WB-MRI reading as the reference standard. Differences in lesion number categories were assessed using marginal homogeneity and kappa statistics. Results Of 56 patients (36 men; mean age = 63.5 years), 39 had myeloma lesions. DWI showed slightly higher sensitivity for detecting myeloma lesions (97.4%) than CT (84.6%–92.3%; P > 0.05). CT showed significantly higher specificity (88.2%) than DWI (52.9%–58.8%; PConclusion CT interpreted according to the IMWG guideline is a diagnostically effective first-line modality with relatively high sensitivity and specificity. DWI alone may not be an acceptable first-line imaging modality because of low specificity.

BACKGROUND In this meta-analysis, we compared the risk of obtaining nondiagnostic results and the diagnostic accuracy for detection of salivary gland malignancy between core needle biopsy (CNB) and fine-needle aspiration (FNA). METHODS All published English-language studies comparing CNB and FNA diagnostic accuracy for salivary gland masses through December 2019 were searched. Pooled risk ratios (RRs) of nondiagnostic results, sensitivities, and specificities of CNB and FNA for salivary gland malignancy diagnosis were determined. Complication rates were compared. RESULTS Six studies (1924 procedures) were quantitatively analyzed. CNB yielded significantly fewer nondiagnostic results (P

Background Plain radiography serves a pivotal role in diagnosing axial spondyloarthritis. However, a broad range of diagnostic performance of plain radiography has been reported. Purpose To perform a systematic review and meta-analysis to measure the diagnostic performance of plain radiography for sacroiliitis in patients suspected of having axial spondyloarthritis using magnetic resonance imaging (MRI) findings as the reference standard. Material and Methods Studies comparing radiography and MRI in the diagnosis of sacroiliitis in patients suspected of having axial spondyloarthritis were searched in PubMed and EMBASE. Additionally, studies analyzed SPondyloaArthritis Caught Early (SPACE), DEvenir des Spondylarthropathies Indifferenciées Récentes (DESIR), GErman Spondyloarthritis Inception Cohort (GESPIC), and South Swedish Arthritis Treatment Group (SSATG) cohorts were manually searched. Pooled sensitivity and specificity of radiography were calculated by using a bivariate random-effects model. Meta-regression analyses were performed to identify the sources of heterogeneity. Results Eight eligible studies with 1579 patients were included. The pooled sensitivity and specificity of radiography were 0.55 (95% confidence interval [CI] = 0.40–0.69) and 0.87 (95% CI = 0.72–0.95). The meta-regression analyses showed prospective study design and criteria for MRI positivity considering only active bone marrow edema were associated with lower sensitivity. Conclusion The plain radiography showed low sensitivity and reasonable specificity in diagnosis of sacroiliitis in patients suspected of having axial spondyloarthritis.

OBJECTIVE. The purpose of this study is to evaluate the diagnostic outcome of ultrasound (US)–guided core needle biopsy (CNB) of soft-tissue tumors and to assess the factors associated with signifi...

To develop and validate prediction models to differentiate acute and chronic vertebral compression fractures based on radiologic and radiomic features on CT.This study included acute and chronic compression fractures in patients who underwent both spine CT and MRI examinations. For each fractured vertebra, three CT findings ([1] cortical disruption, [2] hypoattenuating cleft or sclerotic line, and [3] relative bone marrow attenuation) were assessed by two radiologists. A radiomic score was built from 280 radiomic features extracted from non-contrast-enhanced CT images. Weighted multivariable logistic regression analysis was performed to build a radiologic model based on CT findings and an integrated model combining the radiomic score and CT findings. Model performance was evaluated and compared. Models were externally validated using an independent test cohort.A total to 238 fractures (159 acute and 79 chronic) in 122 patients and 58 fractures (39 acute and 19 chronic) in 32 patients were included in the training and test cohorts, respectively. The AUC of the radiomic score was 0.95 in the training and 0.93 in the test cohorts. The AUC of the radiologic model was 0.89 in the training and 0.83 in the test cohorts. The discriminatory performance of the integrated model was significantly higher than the radiologic model in both the training (AUC, 0.97; p0.01) and the test (AUC, 0.95; p=0.01) cohorts.Combining radiomics with radiologic findings significantly improved the performance of CT in determining the acuity of vertebral compression fractures.

Objectives: To determine the diagnostic accuracy and complication rate of percutaneous transthoracic needle biopsy (PTNB) for subsolid pulmonary nodules and sources of heterogeneity among reported results. Methods: We searched PubMed, EMBASE, and Cochrane libraries (until November 7, 2020) for studies measuring the diagnostic accuracy of PTNB for subsolid pulmonary nodules. Pooled sensitivity and specificity of PTNB were calculated using a bivariate random-effects model. Bivariate meta-regression analyses were performed to identify sources of heterogeneity. Pooled overall and major complication rates were calculated. Results: We included 744 biopsies from 685 patients (12 studies). The pooled sensitivity and specificity of PTNB for subsolid nodules were 90% (95% confidence interval [CI]: 85–94%) and 99% (95% CI: 92–100%), respectively. Mean age above 65 years was the only covariate significantly associated with higher sensitivity (93% vs 85%, p = 0.04). Core needle biopsy showed marginally higher sensitivity than fine-needle aspiration (93% vs 83%, p = 0.07). Pooled overall and major complication rate of PTNB were 43% (95% CI: 25–62%) and 0.1% (95% CI: 0–0.4%), respectively. Major complication rate was not different between fine-needle aspiration and core needle biopsy groups (p = 0.25). Conclusion: PTNB had acceptable performance and a low major complication rate in diagnosing subsolid pulmonary nodules. The only significant source of heterogeneity in reported sensitivities was a mean age above 65 years. Advances in knowledge: This is the first meta-analysis attempting to systemically determine the cause of heterogeneity in the diagnostic accuracy and complication rate of PTNB for subsolid pulmonary nodules.

We compared appendiceal visualization on 2-mSv CT vs. conventional-dose CT (median 7 mSv) in adolescents and young adults and analyzed the undesirable clinical and diagnostic outcomes that followed appendiceal nonvisualization.A total of 3074 patients aged 15-44 years (mean ± standard deviation, 28 ± 9 years; 1672 female) from 20 hospitals were randomized to the 2-mSv CT or conventional-dose CT group (1535 vs. 1539) from December 2013 through August 2016. A total of 161 radiologists from 20 institutions prospectively rated appendiceal visualization (grade 0, not identified; grade 1, unsure or partly visualized; and grade 2, clearly and entirely visualized) and the presence of appendicitis in these patients. The final diagnosis was based on CT imaging and surgical, pathologic, and clinical findings. We analyzed undesirable clinical or diagnostic outcomes, such as negative appendectomy, perforated appendicitis, more extensive than simple appendectomy, delay in patient management, or incorrect CT diagnosis, which followed appendiceal nonvisualization (defined as grade 0 or 1) and compared the outcomes between the two groups.In the 2-mSv CT and conventional-dose CT groups, appendiceal visualization was rated as grade 0 in 41 (2.7%) and 18 (1.2%) patients, respectively; grade 1 in 181 (11.8%) and 81 (5.3%) patients, respectively; and grade 2 in 1304 (85.0%) and 1421 (92.3%) patients, respectively (The use of 2-mSv CT instead of conventional-dose CT impairs appendiceal visualization in more patients. However, appendiceal nonvisualization on 2-mSv CT rarely leads to undesirable clinical or diagnostic outcomes.

Oxalosis is a metabolic disorder characterized by the accumulation of calcium oxalate deposits in various organ systems. Bone oxalosis is a systemic manifestation of oxalosis, in which calcium oxalate deposits accumulate in the skeletal system. This report describes a 69-year-old female patient who presented with right hip pain and was later found to have an osseous mass-like lesion in the right proximal femur, with radiographic findings resembling those of a benign bone tumor. CT-guided biopsy and surgical biopsy showed that the mass had pathologic findings typical of bone oxalosis. Because the patient had no predisposing factors for systemic oxalosis and had no hyperoxalemia or hyperoxaluria, she could be diagnosed with localized bone oxalate deposition disease or bone oxaloma rather than bone oxalosis. This is the first report of this clinical entity to present as a benign-appearing bone mass and without any predisposing systemic causes.

OBJECTIVE. The objective of our study was to compare the sensitivity of a deep learning (DL) algorithm with the assessments by radiologists in diagnosing osteonecrosis of the femoral head (ONFH) using digital radiography. MATERIALS AND METHODS. We performed a two-center, retrospective, noninferiority study of consecutive patients (≥ 16 years old) with a diagnosis of ONFH based on MR images. We investigated the following four datasets of unilaterally cropped hip anteroposterior radiographs: training (n = 1346), internal validation (n = 148), temporal external test (n = 148), and geographic external test (n = 250). Diagnostic performance was measured for a DL algorithm, a less experienced radiologist, and an experienced radiologist. Noninferiority analyses for sensitivity were performed for the DL algorithm and both radiologists. Subgroup analysis for precollapse and postcollapse ONFH was done. RESULTS. Overall, 1892 hips (1037 diseased and 855 normal) were included. Sensitivity and specificity for the temporal external test set were 84.8% and 91.3% for the DL algorithm, 77.6% and 100.0% for the less experienced radiologist, and 82.4% and 100.0% for the experienced radiologist. Sensitivity and specificity for the geographic external test set were 75.2% and 97.2% for the DL algorithm, 77.6% and 75.0% for the less experienced radiologist, and 78.0% and 86.1% for the experienced radiologist. The sensitivity of the DL algorithm was noninferior to that of the assessments by both radiologists. The DL algorithm was more sensitive for precollapse ONFH than the assessment by the less experienced radiologist in the temporal external test set (75.9% vs 57.4%; 95% CI of the difference, 4.5-32.8%). CONCLUSION. The sensitivity of the DL algorithm for diagnosing ONFH using digital radiography was noninferior to that of both less experienced and experienced radiologist assessments.

To develop and validate a scoring system integrating MRI and laboratory findings to differentiate necrotizing fasciitis (NF) from non-necrotizing fasciitis (non-NF). This retrospective study included 144 subjects who underwent surgery in one of three tertiary referral centers for NF or cellulitis with non-NF. The development cohort consisted of 96 subjects (NF = 47; non-NF = 49) from one center, and the validation cohort consisted of 48 subjects (NF = 23; cellulitis with non-NF = 25) from two different centers. The Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) scoring system and five MRI findings (thickening of the intermuscular deep fascia ≥ 3 mm, extensive involvement of the deep fascia, multi-compartmental involvement in one extremity, presence of gas, and contrast-enhancement pattern) were included in univariate and multivariate logistic regression analysis to identify independent predictors of NF. An additive scoring system was developed using the coefficients of the final regression model. Model performance was assessed for discrimination and calibration. The scoring system was externally validated. The final scoring system consisted of three variables: thickening of the deep fascia ≥ 3 mm, multi-compartmental involvement, and LRINEC score. The new predictive model showed improved performance (area under the receiver operating characteristic curve [AUC], 0.862; positive and negative predictive values, 82% and 79%, respectively), compared with the LRINEC score alone (0.814, 77% and 67%, respectively). The model also showed good discrimination with the external validation dataset (AUC, 0.933). Differentiation of NF from severe cellulitis with non-NF can be achieved with the new predictive scoring system. • The new predictive scoring system integrating two MRI findings with the LRINEC score can help in the differentiation of necrotizing fasciitis from severe cellulitis with non-necrotizing fasciitis. • Thickening of the deep fascia ≥ 3 mm and multi-compartmental involvement were the most important MRI findings for the differentiation.

Purpose To evaluate the osseous anatomy of the proximal femur extracted from a 3D-MRI volumetric interpolated breath-hold (VIBE) sequence using either a Dixon or water excitation (WE) fat suppression method, and to measure the overall difference using CT as a reference standard. Material and methods This retrospective study reviewed imaging of adult patients with hip pain who underwent 3D hip MRI and CT. A semi-automatically segmented CT model served as the reference standard, and MRI segmentation was performed manually for each unilateral hip joint. The differences between Dixon-VIBE-3D-MRI vs. CT, and WE-VIBE-3D-MRI vs. CT, were measured. Equivalence tests between Dixon-VIBE and WE-VIBE models were performed with a threshold of 0.1 mm. Bland–Altman plots and Lin’s concordance-correlation coefficient were used to analyze the agreement between WE and Dixon sequences. Subgroup analyses were performed for the femoral head/neck, intertrochanteric, and femoral shaft areas. Results The mean and maximum differences between Dixon-VIBE-3D-MRI vs. CT were 0.2917 and 3.4908 mm, respectively, whereas for WE-VIBE-3D-MRI vs. CT they were 0.3162 and 3.1599 mm. The mean differences of the WE and Dixon methods were equivalent (P = 0.0292). However, the maximum difference was not equivalent between the two methods and it was higher in WE method. Lin’s concordance-correlation coefficient showed poor agreement between Dixon and WE methods. The mean differences between the CT and 3D-MRI models were significantly higher in the femoral shaft area (P = 0.0004 for WE and P = 0.0015 for Dixon) than in the other areas. The maximum difference was greatest in the intertrochanteric area for both techniques. Conclusion The difference between 3D-MR and CT models were acceptable with a maximal difference below 3.5mm. WE and Dixon fat suppression methods were equivalent. The mean difference was highest at the femoral shaft area, which was off-center from the magnetization field.

To develop and validate a combined radiomics-clinical model to predict malignancy of vertebral compression fractures on CT. One hundred sixty-five patients with vertebral compression fractures were allocated to training (n = 110 [62 acute benign and 48 malignant fractures]) and validation (n = 55 [30 acute benign and 25 malignant fractures]) cohorts. Radiomics features (n = 144) were extracted from non-contrast-enhanced CT images. Radiomics score was constructed by applying least absolute shrinkage and selection operator regression to reproducible features. A combined radiomics-clinical model was constructed by integrating significant clinical parameters with radiomics score using multivariate logistic regression analysis. Model performance was quantified in terms of discrimination and calibration. The model was internally validated on the independent data set. The combined radiomics-clinical model, composed of two significant clinical predictors (age and history of malignancy) and the radiomics score, showed good calibration (Hosmer-Lemeshow test, p > 0.05) and discrimination in both training (AUC, 0.970) and validation (AUC, 0.948) cohorts. Discrimination performance of the combined model was higher than that of either the radiomics score (AUC, 0.941 in training cohort and 0.852 in validation cohort) or the clinical predictor model (AUC, 0.924 in training cohort and 0.849 in validation cohort). The model stratified patients into groups with low and high risk of malignant fracture with an accuracy of 98.2% in the training cohort and 90.9% in the validation cohort. The combined radiomics-clinical model integrating clinical parameters with radiomics score could predict malignancy in vertebral compression fractures on CT with high discriminatory ability. • A combined radiomics-clinical model was constructed to predict malignancy of vertebral compression fractures on CT by combining clinical parameters and radiomics features. • The model showed good calibration and discrimination in both training and validation cohorts. • The model showed high accuracy in the stratification of patients into groups with low and high risk of malignant vertebral compression fractures.

Purpose To build and validate a decision tree model using classification and regression tree (CART) analysis to distinguish lipoma and lipoma variants from well-differentiated liposarcoma of the extremities and superficial trunk. Methods This retrospective study included patients who underwent surgical resection and preoperative contrast-enhanced MR imaging for lipoma, lipoma variants, and well-differentiated liposarcoma in two tertiary referral centers. Six MRI findings (tumor size, anatomical location, tumor depth, shape, enhancement pattern, and presence of intermingled muscle fibers) and two demographic factors (patient age and sex) were assessed to build a classification tree using CART analysis with minimal error cross-validation pruning based on a complexity parameter. Results The model building cohort consisted of 231 patients (186 lipoma and lipoma variants and 45 well-differentiated liposarcoma) from one center, while the validation cohort consisted of 157 patients (136 lipoma and lipoma variants and 21 well-differentiated liposarcoma) from another center. In the CART analysis, the contrast enhancement pattern (no enhancement or thin septal enhancement versus thick septal, nodular, confluent hazy, or solid enhancement) was the first partitioning predictor, followed by a maximal tumor size of 12.75 cm. The tree model allowed distinction of lipoma and lipoma variants from well-differentiated liposarcoma in both the model building cohort (C-statistics, 0.955; sensitivity 80 %, specificity 94.62 %, accuracy 91.77 %) and the external validation cohort (C-statistics, 0.917; sensitivity 66.67 %, specificity 95.59 %, accuracy 91.72 %). Conclusion The distinction of lipoma and lipoma variants from well-differentiated liposarcoma can be achieved with the simple classification tree model.

Spontaneous intracranial hypotension (SIH), caused by CSF leaks, can trigger headaches, and is treated using epidural blood patch (EBP) procedures. We aimed to determine the effectiveness of a newly devised two-site blind EBP procedure as the initial treatment for SIH and compare its effectiveness with that of conventional targeted EBP. We retrospectively reviewed data for 116 patients who underwent EBP for SIH between November 2013 and April 2017. Patients were divided into two groups: those who initially received two-site blind EBP (n = 28) at the cervicothoracic (C7/T1) and thoracolumbar junctions (T12/L1) for sealing CSF leaks at all levels, and those who received targeted EBP after CT myelography (n = 88). The initial recovery status and the need for additional blood patches were evaluated. In total, 71.4% and 69.3% patients in the two-site blind EBP and targeted EBP groups, respectively, experienced complete relief after the first patch (p > .05); collectively, 89.3% and 96.6% patients, respectively, experienced complete or partial relief after the first patch (p > .05). A second EBP was required by 35.7% and 29.5% patients in the two-site blind EBP and targeted EBP groups, respectively, with no significant between-group difference (p > .05). All patients ultimately experienced relief; a few required up to four patches. We observed similar outcomes after initial two-site blind EBP and targeted EBP. Therefore, two-site blind EBP is an effective alternative to conventional targeted EBP and a potential initial patch of choice for SIH treatment.

This study was conducted to evaluate the added value of diffusion-weighted imaging (DWI) to conventional magnetic resonance imaging (MRI) for predicting fascial involvement of soft tissue sarcomas located in close proximity to fascial boundaries. This retrospective study included 29 patients with surgically resected soft tissue sarcomas located in proximity to deep fascia and with a curvilinear tail-like hyperintensity in the adjacent fascia on T2-weighted images. All patients underwent conventional MRI and DWI at 3.0 T and had detailed histologic reports on involvement of fascia. Two musculoskeletal radiologists with 21 and 1 year of experience independently reviewed conventional MRI and conventional imaging with added DWI. Readers scored their confidence for tumor involvement of fascia using a three-point scale. Diagnostic performance (area under the curve [Az]) of the two MRI sets was assessed with receiver-operating characteristic curve analysis. Fascial involvement was present in 22/29 patients (75.9%). Both readers showed improvement in diagnostic performance with the addition of DWI (Az, from 0.545 to 0.792 and from 0.646 to 0.792 for reader 1 and reader 2, respectively). Adding DWI did not improve sensitivity or specificity for either reader (p > 0.05). Interobserver agreement for the confidence scores improved from fair to moderate with the addition of DWI (κ, from 0.390 to 0.560). Adding DWI to conventional MRI improved diagnostic performance on prediction of fascial involvement of soft tissue sarcomas located in proximity to fascia, without significant improvement in sensitivity or specificity. • Adding DWI to conventional MRI improved readers’ confidence level for the prediction of fascial involvement of soft tissue sarcomas that are close to the deep fascia. • Addition of DWI also improved interobserver agreement. • Conversely, compared with conventional MRI, adding DWI did not significantly improve the sensitivity or specificity for the detection of fascial involvement.

We aimed to analyze the pattern of teres minor atrophy with regard to its two-bundle anatomy and to assess its association with clinical factors. Shoulder MRIs performed between January and December 2016 were retrospectively reviewed. Images were evaluated for the presence and pattern of isolated teres minor atrophy. Isolated teres minor atrophy was categorized into complete or partial pattern, and partial pattern was further classified according to the portion of the muscle that was predominantly affected. The medical records were reviewed to identify clinical factors associated with teres minor atrophy. Seventy-eight shoulders out of 1,264 (6.2%) showed isolated teres minor atrophy; complete pattern in 41.0%, and partial pattern in 59.0%. Most cases of partial pattern had predominant involvement of the medial–dorsal component (82.6%). There was no significant association between teres minor atrophy and previous trauma, shoulder instability, osteoarthritis, and previous operation. The history of shoulder instability was more frequently found in patients with isolated teres minor atrophy (6.4%), compared with the control group (2.6%), although the difference was not statistically significant. Isolated teres minor atrophy may be either complete or partial, and the partial pattern may involve either the medial–dorsal or the lateral–ventral component of the muscle. The imaging findings of partial pattern teres minor atrophy indicate that the two muscle components may have separate innervation.

Objective To evaluate the rates of technical success, clinical success, and complications of fluoroscopy-guided lumbar cerebrospinal fluid drainage. Materials and methods This retrospective study was approved by the Institutional Review Board of our hospital, and informed consent was waived. Ninety-six procedures on 60 consecutive patients performed July 2008 to December 2013 were evaluated. The patients were referred for the fluoroscopy-guided procedure due to failed attempts at a bedside approach, a history of lumbar surgery, difficulty cooperating, or obesity. Fluoroscopy-guided lumbar drainage procedures were performed in the lateral decubitus position with a midline puncture of L3/4 in the interspinous space. The catheter tip was positioned at the T12/L1 level, and the catheter was visualized on contrast agent-aided fluoroscopy. A standard angiography system with a rotatable C-arm was used. The definitions of technical success, clinical success, and complications were defined prior to the study. Results The technical and clinical success rates were 99.0% (95/96) and 89.6% (86/96), respectively. The mean hospital stay for an external lumbar drain was 4.84 days. Nine cases of minor complications and eight major complications were observed, including seven cases of meningitis, and one retained catheter requiring surgical removal. Conclusion Fluoroscopy-guided external lumbar drainage is a technically reliable procedure in difficult patients with failed attempts at a bedside procedure, history of lumbar surgery, difficulties in cooperation, or obesity.

Purpose To evaluate the association of computed tomography (CT) texture features of locally advanced rectal cancer with neoadjuvant chemoradiotherapy (CRT) response and disease-free survival (DFS). Methods and findings The institutional review board approved this retrospective study. 95 patients who received neoadjuvant CRT, followed by surgery, for locally advanced rectal cancer were included. Texture features (entropy, uniformity, kurtosis, skewness, and standard deviation) were assessed in pretreatment CT images and obtained without filtration and with Laplacian of Gaussian spatial filter of various filter values (1.0, 1.5, 2.0, and 2.5). Dworak pathologic grading was used for treatment response assessment. Independent t-test was used to compare each texture feature between the treatment responder and non-responder groups. DFS was assessed with Kaplan-Meier method, and differences were compared with log-rank test. Cox proportional hazards models were constructed to predict prognosis based on stage, age, and each texture feature. Treatment responders (n = 32) showed significantly lower entropy, higher uniformity, and lower standard deviation in no filtration, fine (1.0), and medium (1.5) filter values. Entropy, uniformity, and standard deviation without filtration showed significant difference in DFS in Kaplan-Meier analysis (P = 0.015, 0.025, and 0.038). Homogeneous texture features (≤ 6.7 for entropy, > 0.0118 for uniformity, and ≤ 28.06 for standard deviation) were associated with higher DFS. Entropy, uniformity, and standard deviation were independent texture features in predicting DFS (P = 0.017, 0.03, and 0.036). Conclusions Homogeneous texture features are associated with better neoadjuvant CRT response and higher DFS in patients with locally advanced rectal cancer.