Identification of early predictors of clinical outcomes of COVID-19 outbreak in an Italian single center using a machine-learning approach.

OBJECTIVE: SARS-CoV-2 disease (COVID-19) has become a pandemic disease, determining a public health emergency. The use of artificial intelligence in identifying easily available biomarkers capable of predicting the risk for severe disease may be helpful in guiding clinical decisions. The aim of the study was to investigate the ability of interleukin (IL)-6, troponin I, and D-dimer to identify patients with COVID-19 at risk for intensive care unit (ICU)-admission and death by using a machine-learning predictive model. PATIENTS AND METHODS: Data on demographic characteristics, underlying comorbidities, symptoms, physical and radiological findings, and laboratory tests have been retrospectively collected from electronic medical records of patients admitted to Policlinico A. Gemelli Foundation from March 1, 2020, to September 15, 2020, by using artificial intelligence techniques. RESULTS: From an initial cohort of 425 patients, 146 met the inclusion criteria and were enrolled in the study. The in-hospital mortality rate was 15%, and the ICU admission rate was 41%. Patients who died had higher troponin I (p-value<0.01) and IL-6 values (p-value=0.04), compared to those who survived. Patients admitted to ICU had higher levels of troponin I (p-value<0.01) and IL-6 (p-value<0.01), compared to those not admitted to ICU. Threshold values to predict in-hospital mortality and ICU admission have been identified. IL-6 levels higher than 15.133 ng/L have been associated with a 22.91% risk of in-hospital mortality, and IL-6 levels higher than 25.65 ng/L have been associated with a 56.16% risk of ICU admission. Troponin I levels higher than 12 ng/L have been associated with a 26.76% risk of in-hospital mortality and troponin I levels higher than 12 ng/L have been associated with a 52.11% risk of ICU admission. CONCLUSIONS: Levels of IL-6 and troponin I are associated with poor COVID-19 outcomes. Cut-off values capable of predicting in-hospital mortality and ICU admission have been identified. Building a predictive model using a machine-learning approach may be helpful in supporting clinical decisions in a more precise and personalized way.

Transient ischemic attack and minor stroke as "surgeons affairs": a narrative review.

OBJECTIVE: The scope of this paper is to review the subtypes of transient ischemic attack (TIA) and minor stroke (mS) in which a surgical treatment is needed, discussing the importance and the timing of a multidisciplinary approach, in order to achieve an optimized management and prevent major strokes or other critical complications. MATERIALS AND METHODS: The keywords "transient ischemic attack," "minor stroke," "surgical treatment," "vascular surgery," "heart surgery," "neurosurgery," and "multidisciplinary" were searched using MEDLINE, EMBASE, and Scopus. Relevant search results were discussed by the authors for references inclusion. RESULTS: Notwithstanding that best medical therapy is usually the first choice for the most part of cases, there are specific but recurrent etiologies that must be properly recognized because of a potential surgical approach, even in urgency. In fact, symptomatic carotid stenosis, or particular cases of hemodynamic cerebrovascular events, should be promptly referred to vascular surgeon, since increasing evidences highlighted a benefit from an early artery revascularization. In addition, beyond arrhythmic causes, cardioembolic events due to bacterial endocarditis and atrial myxoma should be quickly diagnosed, possibly in emergency department, because they are a presumptive urgency for heart surgery. In addition to the above-mentioned conditions, in patients suffering from vertebrobasilar TIA or mS, clinicians should keep in mind the Bow Hunter disease, because surgical artery decompression can represent the only suitable treatment in selected cases. CONCLUSIONS: TIA and mS require a multidisciplinary in order to discuss therapeutic options, comparing risks and benefits and determining the best timing for an optimized management.

MRI-derived radiomics to guide post-operative management of glioblastoma: Implication for personalized radiation treatment volume delineation.

Background: The glioblastoma's bad prognosis is primarily due to intra-tumor heterogeneity, demonstrated from several studies that collected molecular biology, cytogenetic data and more recently radiomic features for a better prognostic stratification. The GLIFA project (GLIoblastoma Feature Analysis) is a multicentric project planned to investigate the role of radiomic analysis in GB management, to verify if radiomic features in the tissue around the resection cavity may guide the radiation target volume delineation. Materials and methods: We retrospectively analyze from three centers radiomic features extracted from 90 patients with total or near total resection, who completed the standard adjuvant treatment and for whom we had post-operative images available for features extraction. The Manual segmentation was performed on post gadolinium T1w MRI sequence by 2 radiation oncologists and reviewed by a neuroradiologist, both with at least 10 years of experience. The Regions of interest (ROI) considered for the analysis were: the surgical cavity ± post-surgical residual mass (CTV_cavity); the CTV a margin of 1.5 cm added to CTV_cavity and the volume resulting from subtracting the CTV_cavity from the CTV was defined as CTV_Ring. Radiomic analysis and modeling were conducted in RStudio. Z-score normalization was applied to each radiomic feature. A radiomic model was generated using features extracted from the Ring to perform a binary classification and predict the PFS at 6 months. A 3-fold cross-validation repeated five times was implemented for internal validation of the model. Results: Two-hundred and seventy ROIs were contoured. The proposed radiomic model was given by the best fitting logistic regression model, and included the following 3 features: F_cm_merged.contrast, F_cm_merged.info.corr.2, F_rlm_merged.rlnu. A good agreement between model predicted probabilities and observed outcome probabilities was obtained (p-value of 0.49 by Hosmer and Lemeshow statistical test). The ROC curve of the model reported an AUC of 0.78 (95% CI: 0.68-0.88). Conclusion: This is the first hypothesis-generating study which applies a radiomic analysis focusing on healthy tissue ring around the surgical cavity on post-operative MRI. This study provides a preliminary model for a decision support tool for a customization of the radiation target volume in GB patients in order to achieve a margin reduction strategy.

Safety and Diagnostic Efficacy of Gadobenate Dimeglumine in MRI of the Brain and Spine of Neonates and Infants.

BACKGROUND AND PURPOSE: Contrast-enhanced MR imaging provides essential information for pediatric imaging applications. We evaluated gadobenate dimeglumine for contrast-enhanced MR imaging of infants younger than 2 years of age. MATERIALS AND METHODS: Ninety children younger than 2 years of age (including 55 children younger than 1 year) who underwent enhanced MR imaging of the CNS with gadobenate dimeglumine at 0.1 mmol/kg body weight ± 25% by volume were retrospectively enrolled at 2 imaging centers. Safety data were assessed for adverse events and, when available, vital signs and electrocardiogram and clinical laboratory values obtained from 48 hours before until 48 hours after the MR imaging examination. The efficacy of gadobenate dimeglumine-enhanced MR imaging was evaluated prospectively by 3 blinded, unaffiliated readers in terms of the accuracy of combined pre- and postcontrast images relative to precontrast images alone for differentiation of tumor from non-neoplastic disease and the correct diagnosis of specific disease. Differences were tested using the McNemar test. A possible effect of dose on diagnostic accuracy was assessed using the Fisher exact test. RESULTS: Nine nonserious adverse events were reported for 8 (8.8%) patients. Five adverse events occurred in patients 12 months of age or older. All events occurred at least 24 hours after gadobenate dimeglumine administration, and in each case, the investigating radiologist considered that there was no reasonable possibility of a relationship to gadobenate dimeglumine. No clinically meaningful changes in vital signs, electrocardiogram results, or laboratory parameters were reported. Accurate differentiation of tumor from non-neoplastic disease and exact matching of each specific MR imaging-determined diagnosis with the on-site final diagnosis were achieved in significantly more patients by each reader following evaluation of combined pre- and postcontrast images relative to precontrast images alone (91.0%-94.4% versus 75.3%-87.6%, P < .04, and 66.3%-73.0% versus 52.8%-58.4%, P < .02, respectively). No significant differences (P > .133) in diagnostic accuracy were noted between patients receiving ≤0.08 mmol/kg of gadobenate dimeglumine and patients receiving >0.08 mmol/kg of gadobenate dimeglumine. CONCLUSIONS: Gadobenate dimeglumine is safe and effective for pediatric MR imaging.

Immuno-oncology and interventional oncology: a winning combination. The latest scientific evidence.

OBJECTIVE: Interventional oncology (IO) is an emergent field in interventional radiology that can be considered the fourth pillar of oncology. Interventional oncology has the unique capability to treat malignancy in a loco-regional fashion enabling curative (percutaneous ablation), disease stabilization (intra-arterial chemo/radioembolization), and palliative treatment (such as biliary drainage or nephrostomy). The whole arsenal of IO acts by inducing necrosis and apoptosis, with interactions with the tumour's microenvironment potentially crucial for oncological outcomes. Considering that tumour's microenvironment is a pivotal target for both immuno-oncology and interventional-oncology, the interactions between these two anti-tumour weapons must be investigated to understand their synergy. Interestingly, substantial efforts have been directed to understand which technique combinations are best for specific tumours. This review article summarizes the latest scientific evidence highlighting the future prospective of this winning combination, integrating evidence-reported literature and experience-based perceptions.

Magnetic resonance arthrography accuracy in the detection of labral tears in young patients with chronic unstable shoulder: correlation with arthroscopy.

The aim of this study is to determine the diagnostic performance of Magnetic Resonance Arthrography (MRA) in evaluating lesions of the glenoid labrum, in young active patients with chronic unstable shoulder, compared to shoulder arthroscopy. We retrospectively considered 65 MRA examinations, performed between December 2011 and January 2018. Among them, thirty-five patients (31 men, 4 women; mean age, 27.3 years; range, 16-53 years; 4 patients with a previous arthroscopy of the same shoulder) underwent shoulder arthroscopy after MRA. Arthroscopic reports were collected and analyzed for the correlation with MRA results.

Brain DSC MR Perfusion in Children: A Clinical Feasibility Study Using Different Technical Standards of Contrast Administration.

BACKGROUND AND PURPOSE: Dynamic susceptibility contrast MR perfusion imaging has limited results in children due to difficulties in reproducing technical standards derived from adults. This prospective, multicenter study aimed to determine DSC feasibility and quality in children using custom administration of a standard dose of gadolinium. MATERIALS AND METHODS: Eighty-three consecutive children with brain tumors underwent DSC perfusion with a standard dose of gadobutrol administered by an automated power injector. The location and size of intravenous catheters and gadobutrol volume and flow rates were reported, and local and/or systemic adverse effects were recorded. DSC was qualitatively evaluated by CBV maps and signal intensity-time curves and quantitatively by the percentage of signal drop and full width at half-maximum, and the data were compared with the standards reported for adults. Quantitative data were grouped by flow rate, and differences among groups were assessed by analysis of covariance and tested for statistical significance with a t test. RESULTS: No local or systemic adverse events were recorded independent of catheter location (63 arm, 14 hand, 6 foot), size (24-18 ga), and flow rates (1-5 mL/s). High-quality CBV maps and signal intensity-time curves were achieved in all patients, and quantitative evaluations were equal or superior to those reported for adults. No significant differences (P ≥ .05) were identified among the higher-flow-rate groups in the quantitative data. CONCLUSIONS: A custom administration of a standard dose of gadobutrol allows safe and high-quality DSC MR perfusion imaging in children.

The ten commandments of liver ablation: expert discussion and report from Mediterranean Interventional Oncology (MIOLive) congress 2017.

Percutaneous liver ablation has become a cornerstone of the recently developed subspecialty of radiology - that is, interventional oncology. Thermal ablation technology has evolved rapidly during the past decades, with substantial technical and procedural improvements that can help obtain better clinical outcomes and safety profiles. Due to the widespread use of percutaneous ablation, a comprehensive review of the methodologic and technical considerations seems to be mandatory. This article summarizes the expert discussion and report from Mediterranean Interventional Oncology Live Congress (MIOLive 2017) that was held in Rome, Italy, integrating evidence-reported literature and experience-based perceptions, to assist not only residents and fellows who are training in interventional radiology but also practicing colleagues who are approaching to this locoregional treatment.

Diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC) values for detection of malignant vertebral bone marrow lesions.

Malignant spinal bone marrow disorders are one of the major causes of significant morbidity and reduction in quality of life in oncological patients. Thus, the characterization of these conditions is of crucial importance in the management of these patients. Magnetic resonance (MR) imaging plays a vital role in differentiation between benign and malignant spinal bone marrow disorders. However, morphological imaging features, based on T1 and T2 relaxation properties, might fail in differentiating between these conditions because signal characteristics may overlap. Quantitative MR imaging based on diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC) values has been proved to help in defining the nature of the lesion. The aims of this paper were: to review basic principles of DWI technique and ADC maps, to describe DWI and ADC maps appearances of normal vertebral bone marrow briefly, to discuss the DWI and ADC maps characteristics in vertebral malignant lesions, to provide indications for differential diagnosis between malignant and benign lesions.

Primary neoplasms of the small bowel at CT: a pictorial essay for the clinician.

OBJECTIVE: Primary small intestinal neoplasms are uncommon tumors that are often small and difficult to identify. The aim of this paper is to describe CT technique and features in detecting and characterizing the tumors of the small bowel. MATERIALS AND METHODS: This paper focuses on radiological characteristics of benign and malignant primary neoplasms of the small bowel at CT, with special reference to multidetector-CT techniques, type and modality of administration of contrast agents (by oral route or CT-enterography and by nasojejunal tube or CT-enteroclysis). This paper will also provide pictures and description of CT findings of benign and malignant primary neoplasms using examples of CT-enterography and CT-enteroclysis. RESULTS: Among CT modalities, CT-enterography has the advantage of defining the real extension of wall lesions, possible transmural extension, the degree of mesenteric involvement and remote metastasis. Other useful modalities for the diagnosis of such lesions like capsule endoscopy and enteroscopy, provide important information but limited to mucosal changes with lower accuracy on extension and bowel wall involvement or submucosal lesions. CONCLUSIONS: Multidetector-CT, performed after distension of the small bowel with oral contrast material and intravenous injection of iodinated contrast material, is a useful method for the diagnosis and staging of small bowel neoplasms.

The ten commandments of chemoembolization: expert discussion and report from Mediterranean Interventional Oncology (MIOLive) congress 2017.

Transarterial therapies in the setting of primary and secondary liver malignancies are becoming an essential part of the oncology landscape. The mechanism of action of c-TACE is the induction of tumor necrosis due to the high concentration of the chemotherapeutic that is delivered only locally and to the embolic effect that causes ischemia and increased dwell time of the chemotherapeutic in the tumor. Recently, DEB-TACE has emerged as a variation of c-TACE with the potential for the selective delivery of large amounts of drugs to the tumor for a prolonged period, thereby decreasing plasma levels of the chemotherapeutic agent and related systemic effects. There is an increasing consensus that compared with conventional lipiodol-based regimen, DEB-TACE offers standardized methodology, is more reproducible and is associated with improved response and significantly better safety profile. Using an easy to access point by point format, this manuscript summarizes the expert discussion from the Mediterranean Interventional Oncology Live Congress (MIOLive 2017) about the role of TACE in the treatment of liver tumors.

Role of perfusion CT in the evaluation of metastatic nodal tumor response after radiochemotherapy in head and neck cancer: preliminary findings.

OBJECTIVE: To assess changes of CT perfusion parameters (ΔPCTp) of cervical lymph node metastases from head and neck cancer (HNC) before and after radiochemotherapy (RT-CT) and their association with nodal tumor persistence. PATIENTS AND METHODS: Eligibility criteria included HNC (Stage III-IV) candidates for RT-CT. Patients underwent perfusion CT (PCT) at baseline 3 weeks and 3 months after RT-CT. Blood volume (BV), blood flow (BF), mean transit time (MTT) and permeability surface (PS) were calculated. PET/CT examination was also performed at baseline and 3 months after treatment for metabolic assessment. RESULTS: Between July 2012 and May 2016, 27 patients were evaluated. Overall, only 3 patients (11%) experienced tumor persistence in the largest metastatic lymph node. A significant reduction of all PCTp values (p<0.0001), except MTT (from 6.3 to 5.7 s; p=0.089), was observed at 3 weeks post-RT-CT compared to baseline. All PCTp values including MTT were significantly lower at 3-month follow-up compared to baseline (p<0.05). Moreover, a statistically significant association was observed between nodal tumor persistence and high BF values (p=0.045) at 3 months after treatment that did not occur for the other parameters. CONCLUSIONS: Our preliminary findings show that all PCTp except MTT are significantly reduced after RT-CT. High BF values at 3 months post-RT-CT are predictive of nodal tumor persistence.

The ten commandments of hepatic radioembolization: expert discussion and report from Mediterranean Interventional Oncology (MIOLive) congress 2017.

Microsphere and particle technology represent the next-generation agents that have formed the basis of interventional oncology, an evolving subspecialty of interventional radiology. One of these platforms, yttrium-90 microspheres, is increasingly being used as a treatment modality for primary and secondary liver tumors. Due to the widespread use of radioembolization, a comprehensive review of the methodologic and technical considerations seems to be mandatory. This article summarizes the expert discussion and report from Mediterranean Interventional Oncology Live Congress (MIOLive 2017) that was held in Rome, Italy, integrating evidence-reported literature and experience-based perceptions, to assist not only residents and fellows who are training in interventional radiologists but also practicing colleagues who are approaching to this intra-arterial treatment.

A new score predicting intraprocedural risk in patients undergoing CT-guided percutaneous needle pulmonary biopsy (CATH-score).

OBJECTIVE: To develop a new score (CATH-score) for predicting intra-procedural risk in patients undergoing CT-guided percutaneous needle pulmonary biopsy. PATIENTS AND METHODS: 100 CT-guided lung biopsies performed with a 18 Gauge (G) needle (Pilot Group) were reviewed to analyse patient-, lesion- and procedure-related variables to identify risk factors for procedural complications (pneumothorax and parenchymal bleeding) and diagnosis failure. A scoring system for predicting complications and choosing the right needle (16 G, 18 G, 21 G) was developed using risk factors weighting and prospectively applied to 153 consecutive biopsies (CATH-score Group); complications and diagnostic rates obtained were compared with a group of patients (Control Group) that underwent lung biopsy; in this group of patients the choice of the calliper of the needle was based on the operator experience. RESULTS: lesion diameter (p=0.03), central location of lesion (p=0.02), centrilobular emphysema (p=0.04) and trans-pulmonary needle route (p=0.002) were associated with a higher complications rate in Pilot Group and were selected as risk factors to include in the CATH-score definition. Risk factors "cut-off" values were identified (Receiver Operating Characteristics curves) and risk-stratification groups were classified as follows: low (16 G, score 1), intermediate (18 G, score 2), and high procedural risk score (21 G, score 3). CATH-score usage limited complications rate despite a higher number of 16 G needle employed, with a diagnostic performance rising respect to Control Group. CONCLUSIONS: CATH-score seems to be a valuable tool for predicting the risk of complications and choosing the right needle, in order to increase diagnostic performance in patients undergoing TTNA.

Idiopathic SIADH in young patients: don't forget the nose.

Olfactory neuroblastoma (ONB) is an uncommon neuroendocrine sinonasal cancer associated by many authors to ectopic production of several biologically active substances. We report a case of a 31-year-old male patient who presented with idiopathic syndrome of inappropriate secretion of antidiuretic hormone (SIADH). During diagnostic work-up, a CT scan of the head was performed and an ethmoidal ONB was detected. Endoscopical surgery followed by radiotherapy was carried out. Immediately after surgery natraemia levels normalised. Five years later the patient is disease-free. To our knowledge, 17 cases of SIADH associated to ONB have been published. In nine reports, idiopathic SIADH promptly led to the diagnosis of the sinonasal mass as in our clinical case, however, in many reports, correct diagnosis was accomplished months to years later. In young patients with idiopathic inappropriate antidiuretic hormone secretion, a neuroendocrine malignancy of the sinonasal area must be excluded.

Role of DWI assessing nodal involvement and response to neoadjuvant chemotherapy in advanced breast cancer.

OBJECTIVE: To explore the role of diffusion-weighted imaging (DWI) in the staging of axillary lymph nodes and the restaging after neoadjuvant chemotherapy (NAD) in advanced breast cancer. PATIENTS AND METHODS: MRI examinations of forty-two patients diagnosed with advanced breast cancer addressed to NAD and axillary lymph node dissection (ALND) were reviewed. Apparent diffusion coefficients (ADC) of each visible node in DWI in the pathologic axilla (PA) and healthy axilla (HA) were measured at the time of diagnosis (t0) and after chemotherapy (t1); mean values of the ADC were calculated. Patients were classified as responders (R), non-responders (NR), macrometastasis (MA), micrometastasis (Mi). RESULTS: Mean ADC was 0.92 ± 0.07 x 10-3 mm2/sec at t0 and 0.97 ± 0.06 x 10-3 mm2/sec at t1 (p = 0.284) in PA, 0.89 ± 0.06 x 10-3 mm2/sec at t0 and 0.92 ± 0.06 x 10-3 mm2/sec at t1 (p = 0.403) in HA, 0.95 ± 0.111 x 10-3 mm2/sec at t0 and 0.95 ± 0.14 x 10-3 mm2/sec at t1 (p = 0.954) in R group, 0.90 ± 0.09 x 10-3 mm2/sec at t0 and 0.97 ± 0.07 x 10-3 mm2/sec at t1 (p = 0.085) in NR group, 0.86 ± 0.10 x 10-3 mm2/sec at t0 and 0.99 ± 0.09 x 10-3 mm2/sec at t1 (p = 0.055) in MA, and 0.99 ± 0.23 x 10-3 mm2/sec at t0 and 0.95 ± 0.15 x 10-3 mm2/sec at t1 in Mi (p = 0.667). CONCLUSIONS: Mean ADC between PA and HA, R and NR, MA and Mi did not significantly differ at t0 and t1 (p > 0.05). Variation in mean ADC between t0 and t1 was not significant in all groups (p > 0.05), except for a trend toward significance (p = 0.055) in MA. DWI has a potential role in restaging of macrometastatic axillary nodes after NAD.

Modelling tumour volume variations in head and neck cancer: contribution of magnetic resonance imaging for patients undergoing induction chemotherapy.

Primary tumour volume evaluation has predictive value for estimating survival outcomes. Using volumetric data acquired by MRI in patients undergoing induction chemotherapy (IC) these outcomes were estimated before the radiotherapy course in head and neck cancer (HNC) patients. MRI performed before and after IC in 36 locally advanced HNC patients were analysed to measure primary tumour volume. The two volumes were correlated using the linear-log ratio (LLR) between the volume in the first MRI and the volume in the second. Cox's proportional hazards models (CPHM) were defined for loco-regional control (LRC), disease-free survival (DFS) and overall survival (OS). Strict evaluation of the influence of volume delineation uncertainties on prediction of final outcomes has been defined. LLR showed good predictive value for all survival outcomes in CPHM. Predictive models for LRC and DFS at 24 months showed optimal discrimination and prediction capability. Evaluation of primary tumour volume variations in HNC after IC provides an example of modelling that can be easily used even for other adaptive treatment approaches. A complete assessment of uncertainties in covariates required for running models is a prerequisite to create reliable clinically models.

Preoperative embolization of meningiomas with polyvinyl alcohol particles: The benefits are not outweighed by risks.

PURPOSE: The purpose of this study was to define the feasibility, the efficacy and the safety of preoperative embolization (POE) of meningiomas using polyvinyl alcohol (PVA) particles. MATERIALS AND METHODS: Between January 2006 and June 2014, 191 consecutive patients were referred to our institution for the treatment of meningiomas; of these 57 patients were excluded from the study. A total of 64 patients (22 men and 42 women) with a mean age of 58.4±10.8 [SD] years (range: 14-82years) who underwent POE with PVA particles, achieving extensive (>90%) devascularization were ultimately included and compared to 70 patients who had surgery without POE. Surgical time and intraoperative blood loss were compared between the two groups. The duration of procedures and complications related to POE were analyzed. RESULTS: No differences were found between the two groups with respect to intraoperative blood loss. A significant reduction in surgical time was observed for the group who had POE (207.4±79.5 [SD] min vs. 226.9±117.6 [SD] min; P=0.028). In a subgroup analysis, the size and location of meningiomas did not influence these results. The duration of procedures was 41.4±10.5 [SD] min. Minor complications related to POE occurred in 3 out of 64 patients (4.7%). CONCLUSION: POE of meningiomas using PVA particles is effective in reducing surgical time, when extensive tumor devascularization is achieved. However, radiation exposure, the duration of procedures and complications related to POE with PVA particles do not justify this technique in most patients.

Postoperative MR Imaging of Spontaneous Transdural Spinal Cord Herniation: Expected Findings and Complications.

BACKGROUND AND PURPOSE: Spontaneous transdural spinal cord herniation is no longer a rare cause of myelopathy. The high frequency of diagnoses has led to an increase in the number of surgical procedures. The purpose of this study was to describe the spectrum of postoperative MR imaging findings concerning spontaneous transdural spinal cord herniation and to provide a practical imaging approach for differentiating expected changes and complications after an operation. MATERIALS AND METHODS: We retrospectively reviewed MR images from 12 patients surgically treated for spontaneous transdural spinal cord herniation. Surgery comprised either dural defect enlargement or duraplasty procedures. Postoperative follow-ups included at least 3 (early, intermediate, late) MR imaging studies. MR images were analyzed with respect to 3 spinal compartments: intradural intramedullary, intradural extramedullary, and extradural. The meaning and reliability of changes detected on MR images were related to their radiologic and clinical evolution with time. RESULTS: Spinal cord realignment has been stable since the early study, whereas spinal cord signal and thickness evolved during the following scans. Most extramedullary and extradural changes gradually reduced in later MR images. Three patients treated with dural defect enlargements experienced the onset of new neurologic symptoms. In those patients, late MR images showed extradural fluid collection and the development of pial siderosis. CONCLUSIONS: Our findings demonstrate the spectrum of postoperative imaging findings in spontaneous transdural spinal cord herniation. Spinal cord thickness and signal intensity continued to evolve with time; most extramedullary postsurgical changes became stable. Changes observed in later images may be suggestive of complications.