Intra-scan inter-tissue variability can help harmonize radiomics features in CT.

OBJECTIVE: We studied the repeatability and the relative intra-scan variability across acquisition protocols in CT using phantom and unenhanced abdominal series. METHODS: We used 17 CT scans from the Credence Cartridge Radiomics Phantom database and 20 unenhanced multi-site non-pathologic abdominal patient series for which we measured spleen and liver tissues. We performed multiple measurements in extracting 9 radiomics features. We defined a "tandem" as the measurement of a given tissue (or material) by a given radiomics. For each tandem, we assessed the proportion of the variability attributable to repetitions, acquisition protocols, material, or patient. We analyzed the distribution of the intra-scan correlation between pairs of tandems and checked the impact of correlation coefficient greater than 0.90 in comparing paired and unpaired differences. RESULTS: The repeatability of radiomics features depends on the measured material; 56% of tandems were highly repeatable. Histogram-derived radiomics were generally less repeatable. Nearly 60% of relative radiomics measurements had a correlation coefficient higher than 0.90 allowing paired measurements to improve reliability in detecting the difference between two materials. The analysis of liver and spleen tissues showed that measurement variability was negligible with respect to other variabilities. As for phantom data, we found that gray level zone length matrix (GLZLM)-derived radiomics and gray level co-occurrence matrix (GLCM)-derived radiomics were the most correlating features. For these features, relative intra-scan measurements improved the detection of different materials or tissues. CONCLUSIONS: We identified radiomics features for which the intra-scan measurements between tissues are linearly correlated. This property represents an opportunity to improve tissue characterization and inter-site harmonization. KEY POINTS: • The repeatability of radiomics features on CT depends on the measured material or tissue. • Some tandems of radiomics features/tissues are linearly affected by the variability of acquisition protocols on CT. • Relative intra-scan measurements are an opportunity for improving quantitative imaging on CT.

Letter to the editor: "Not all biases are bad: equitable and inequitable biases in machine learning and radiology".

Artificial intelligence algorithms are booming in medicine, and the question of biases induced or perpetuated by these tools is a very important topic. There is a greater risk of these biases in radiology, which is now the primary diagnostic tool in modern treatment. Some authors have recently proposed an analysis framework for social inequalities and the biases at risk of being introduced into future algorithms. In our paper, we comment on the different strategies for resolving these biases. We warn that there is an even greater risk in mixing the notion of equity, the definition of which is socio-political, into the design stages of these algorithms. We believe that rather than being beneficial, this could in fact harm the main purpose of these artificial intelligence tools, which is the care of the patient.

RECIST 1.1 and lesion selection: How to deal with ambiguity at baseline?

Response Evaluation Criteria In Solid Tumors (RECIST) is still the predominant criteria base for assessing tumor burden in oncology clinical trials. Despite several improvements that followed its first publication, RECIST continues to allow readers a lot of freedom in their evaluations. Notably in the selection of tumors at baseline. This subjectivity is the source of many suboptimal evaluations. When starting a baseline analysis, radiologists cannot always identify tumor malignancy with any certainty. Also, with RECIST, some findings can be deemed equivocal by radiologists with no confirmatory ground truth to rely on. In the specific case of Blinded Independent Central Review clinical trials with double reads using RECIST, the selection of equivocal tumors can have two major consequences: inter-reader variability and modified sensitivity of the therapeutic response. Apart from the main causes leading to the selection of an equivocal lesion, due to the uncertainty of the radiological characteristics or due to the censoring of on-site evaluations, several other situations can be described more precisely. These latter involve cases where an equivocal is selected as target or non-target lesions, the management of equivocal lymph nodes and the case of few target lesions. In all cases, awareness of the impact of selecting a non-malignant lesion will lead radiologists to make selections in the most rational way. Also, in clinical trials where the primary endpoint differs between phase 2 (response-related) and phase 3 (progression-related) trials, our impact analysis will help them to devise strategies for the management of equivocal lesions.

Harmonization of radiomic feature distributions: impact on classification of hepatic tissue in CT imaging.

OBJECTIVES: Following the craze for radiomic features (RF), their lack of reliability raised the question of the generalizability of classification models. Inter-site harmonization of images therefore becomes a central issue. We compared RF harmonization processing designed to detect liver diseases in CT images. METHODS: We retrospectively analyzed 76 multi-center portal CT series of non-diseased (NDL) and diseased liver (DL) patients. In each series, we positioned volumes of interest in spleen and liver, then extracted 9 RF (histogram and texture). We evaluated two RF harmonization approaches. First, in each series, we computed the Z-score of liver measurements based on those computed in the spleen. Second, we evaluated the ComBat method according to each imaging center; parameters were computed in the spleen and applied to the liver. We compared RF distributions and classification performances before/after harmonization. We classified NDL versus spleen and versus DL tissues. RESULTS: The RF distributions were all different between liver and spleen (p < 0.05). The Z-score harmonization outperformed for the detection of liver versus spleen: AUC = 93.1% (p < 0.001). For the detection of DL versus NDL, in a case/control setting, we found no differences between the harmonizations: mean AUC = 73.6% (p = 0.49). Using the whole datasets, the performances were improved using ComBat (p = 0.05) AUC = 82.4% and degraded with Z-score AUC = 67.4% (p = 0.008). CONCLUSIONS: Data harmonization requires to first focus on data structuring to not degrade the performances of subsequent classifications. Liver tissue classification after harmonization of spleen-based RF is a promising strategy for improving the detection of DL tissue. KEY POINTS: • Variability of acquisition parameter makes radiomics of CT features non-reproducible. • Data harmonization can help circumvent the inter-site variability of acquisition protocols. • Inter-site harmonization must be carefully implemented and requires designing consistent data sets.

Myoma Hot Spot: Tumor-to-Tumor Metastasis of Thyroid Origin into Uterine Leiomyoma.

INTRODUCTION: Distant metastases of papillary thyroid cancers are rare. Most common metastatic sites include bone and lung, whereas metastases to brain, eye, breast, liver, kidney, muscle, and skin are infrequent and almost always appear in advanced-stage tumor disease. Metastases to ovary and/or uterus are even scarcer. We report herein a very exceptional case of asymptomatic malignant-to-benign tumor-to-tumor metastasis of thyroid origin into a uterine leiomyoma. CASE PRESENTATION: We present the case of a 53-year-old female patient who had a previous history of pT1b N0 M0 R0 papillary carcinoma of the lower left thyroid lobe, treated by total thyroidectomy and central lymph node dissection and two successive administrations of radioactive treatment with iodine-131. Six years later, follow-up imaging disclosed an asymptomatic slow-growing 40-mm-long pedicled subserous heterogeneous uterine myoma including a 12-mm hypervascular nodule, which was suspicious for thyroid malignancy on MRI. DISCUSSION: Histopathology of a hysterectomy specimen disclosed a hypervascular well-limited poorly differentiated trabecular carcinomatous infiltration within the uterine leiomyoma. The immunohistochemical profile of the suspicious nodule was compatible with a thyroid origin. CONCLUSION: A hypervascular "hot spot" intramyoma nodule was the diagnostic clue in a clinical context of hematogenous tumor spread of thyroid origin (increased thyroglobulin level).

Mental health status of cancer research center's care givers: should we worry?

The status of mental health of physicians practicing in cancer research centers is evaluated. To date little information is given in research to date concerning the burnout syndrome. Recommendations are made for a better psychological development of caregivers.

Radiology workflow for RECIST assessment in clinical trials: Can we reconcile time-efficiency and quality?

PURPOSE: In oncology clinical trials, nonconformity issues are frequently reported. Radiological workload is increasing, thus reducing radiologists' availability and affecting diagnostic quality. We compared performances of a standard radiological workflow (SW) and a novel "hybrid workflow" (HW). METHOD: We prospectively studied imaging data of 40 patients included in RECIST 1.1 clinical trials. Ninety-six time-points were reviewed by 7 radiologists and one trained technologist. Nonconformities using the SW were retrieved from hospital archives. For the HW, radiologists performed all baseline evaluations; the technologist made subsequent measurements. Finally, the radiologists checked the technologist's findings before confirming the evaluations. The HW enabled implementation of an electronic reporting system. An independent body compared SW and HW reading times and nonconformity occurrences. RESULTS: Using SW, 19 types of nonconformity were found: blank report (13%); unsigned report (11%); undocumented change of tumor burden (10%); undocumented new lesions (9%); missing/wrong patients' appointment dates (7%); undocumented tumor location (5%); error in tumor burden change (5%). SW and HW nonconformities affected 55% (179/323) and 5% (2/40) of reports, respectively (p < 0.001). HW nonconformities were: one inaccurate login name was used on the platform, and one erroneous time-point number. On average, SW required 11'30″ [10'06″; 13'20″] per time-point. HW required 1'35″ [40″; 5'08″] for radiologists, and 12'18″ [11'12″; 14'18″] for the technologist. CONCLUSIONS: HW significantly reduced the number of trial nonconformities and saved 87% of radiologists' time while enabling them to apply their expertise to final decisions. HW could offer an effective opportunity for cost reduction associated with improved imaging trial quality.

CT-Guided Percutaneous Gastrostomy without Preliminary Placement of a Nasogastric Tube.

Percutaneous radiologic gastrostomy (PRG) requires preliminary gastric inflation through a nasogastric tube (NGT) to safely perform gastric puncture. However, in case of pharyngeal or esophageal obstruction, NGT placement may be impossible even with a hydrophilic angiography catheter and wire. This brief report describes percutaneous computed tomography (CT)-guided gastrostomy with a 2-stick approach without nasogastric insufflation in 13 patients. Technical success rate was 100% with a mean of 1.8 punctures ± 1.0 to access the gastric lumen. Traversal of the colon and liver with a 22-gauge needle was necessary in 4 and 1 patients, respectively. There were no major complications. Minor complications occurred in 6 patients (46%). CT-guided percutaneous gastrostomy is technically feasible with minimal morbidity.

Diffusion-weighted MRI is not superior to FDG-PET/CT for the detection of neck recurrence in well-differentiated thyroid carcinoma.

BACKGROUND: Management of patients with well-differentiated thyroid carcinoma (WDTC) and positive thyroglobulin (Tg)/negative iodine-131 whole body scintigraphy (WBS) remains challenging. Here, we investigate the specific role of diffusion-weighted magnetic resonance imaging of the neck (DW-MRI) as compared to rhTSH stimulated FDG-PET/CT in such patients. METHODS: Patients with WDTC, positive Tg/negative WBS were prospectively enrolled in the study. FDG-PET/CT and neck DW-MRI were performed on the same day after rhTSH stimulation. Neck-US was performed 24 hours after FDG-PET/CT and MRI to guide fine-needle aspiration (FNA). Patients with positive FNA underwent surgery. Patient with negative workup underwent new explorations at 6 and 18 months. RESULTS: A total of 86 FDG-PET/CT and 83 DW-MRI tests were performed in 40 patients (23 females; 17 males; 52±16 years). For detection of neck recurrences, sensitivity was equivalent for FDG-PET/CT and to DW-MRI at baseline (46% vs. 43%), at 6 months (30% vs. 20%) and at 18 months (11 vs. 10%). The comparison with a non-weighted Kappa test shows significant concordance between FDG-PET/CT and DW-MRI (K=0.741±0.062; P<0.0001). A relationship was observed between Tg and results of FDG-PET/CT, but not for DW-MRI. FDG-PET/CT permitted to detect iodine-refractory distant metastasis in 4 patients. CONCLUSIONS: In Tg-positive/WBS-negative DTC patients, low tumour burden, neck DW-MRI does not provide additional information compared to rhTSH-stimulated FDG-PET/CT. FDG-PET/CT has the best sensitivity, is acceptable for patients, allows whole body exploration and distant metastasis detections, and is correlated with Tg levels.

Focused ultrasound for the treatment of bone metastases: effectiveness and feasibility.

BACKGROUND: To evaluate the effectiveness and feasibility of high-intensity focused ultrasound (HIFU) for the treatment of bone metastases. METHODS: A single-center prospective study was made involving 17 consecutive patients with symptomatic bone metastases. Patients were treated by Focused Ultrasound (FUs) performed with magnetic resonance (MR) guidance. Surgical treatment or radiotherapy treatment was not indicated for patients who underwent FUs. Lesions were located in the appendicular and axial skeleton and consisted of secondary symptomatic lesions. The clinical course of pain was evaluated using the Visual Analog Scale (VAS) before treatment, at 1 week, and at 1 month after treatment and the Oral Morphine Equivalent Daily Dose (OMEDD) was also recorded. We used Wilcoxon signed rank test to assess change in patient pain (R CRAN software V 3.1.1). RESULTS: We observed a significant decrease in the pain felt by patients between pre- procedure and 1 week post-procedure (p = 2.9.10-4), and pre-procedure and 1 month post-procedure (p = 3.10-4). The proportion of responders according to the International Bone Metastases Consensus Working Party was: Partial Response 50% (8/16) and Complete Response 37.5% (6/16). CONCLUSIONS: HIFU under MR-guidance seems to be an effective and safe procedure in the treatment of symptomatic bone lesions for patients suffering from metastatic disease. A significant decrease of patient pain was observed. TRIAL REGISTRATION: NCT01091883. Registered 24 March 2010. Level of evidence: Level 3.

Effects of relaxing therapies on patient's pain during percutaneous interventional radiology procedures.

BACKGROUND: Interventional radiology procedures in cancer patients cause stress and anxiety. Our objective was to relate our experience in the use of sophrology techniques during interventional radiology procedures and evaluate the effects on patient's pain and anxiety. METHODS: We present a prospective observational study on 60 consecutive patients who underwent interventional radiology procedures in a context of oncologic management from September 2017 to March 2018. Forty-two patients were asked if they wished to benefit from the sophrology and hypnosis techniques during their procedure. A control group was also made including 18 patients. Anxiety level and pain were evaluated using the visual analog scale (VAS) before and during procedures. RESULTS: We observed a significant decrease in anxiety experienced by patients during interventional radiology procedures compared to before procedures in the sophrology group (P=3.318E-08), and a level of anxiety and pain during gestures inferior to that of the control group (P=2.035E-06 and 7.03E-05 respectively). CONCLUSIONS: Relaxing therapies, such as sophrology and hypnosis, seems to be an interesting additional tool for the management of patients in interventional oncology, inducing a decrease of stress, pain, and anxiety in patients.

A review of existing and potential computer user interfaces for modern radiology.

The digitalization of modern imaging has led radiologists to become very familiar with computers and their user interfaces (UI). New options for display and command offer expanded possibilities, but the mouse and keyboard remain the most commonly utilized, for usability reasons. In this work, we review and discuss different UI and their possible application in radiology. We consider two-dimensional and three-dimensional imaging displays in the context of interventional radiology, and discuss interest in touchscreens, kinetic sensors, eye detection, and augmented or virtual reality. We show that UI design specifically for radiologists is key for future use and adoption of such new interfaces. Next-generation UI must fulfil professional needs, while considering contextual constraints. TEACHING POINTS: • The mouse and keyboard remain the most utilized user interfaces for radiologists. • Touchscreen, holographic, kinetic sensors and eye tracking offer new possibilities for interaction. • 3D and 2D imaging require specific user interfaces. • Holographic display and augmented reality provide a third dimension to volume imaging. • Good usability is essential for adoption of new user interfaces by radiologists.

Percutaneous Facet Screw Fixation in the Treatment of Symptomatic Recurrent Lumbar Facet Joint Cyst: A New Technique.

We present a case of percutaneous treatment of symptomatic recurrent lumbar facet joint cyst resistant to all medical treatments including facet joint steroid injection. Percutaneous transfacet fixation was then performed at L4-L5 level with a cannulated screw using CT and fluoroscopy guidance. The procedure time was 30 min. Using the visual analog scale (VAS), pain decreased from 9.5, preoperatively, to 0 after the procedure. At 6-month follow-up, an asymptomatic cystic recurrence was observed, which further reduced at the 1-year follow-up. Pain remained stable (VAS at 0) during all follow-ups. CT- and fluoroscopy-guided percutaneous cyst rupture associated with facet screw fixation could be an alternative to surgery in patients suffering from a symptomatic recurrent lumbar facet joint cyst.

Percutaneous consolidation of loosened spine arthrodesis under CT and fluoroscopy guidance by radiologists: a new useful technique.

OBJECTIVE: The objective was to evaluate percutaneous computed tomography (CT) and fluoroscopy-guided injection of bone cement for consolidation of loosened posterior arthrodesis performed by radiologists. METHODS: A single-centre prospective study involving four consecutive patients (three women, one man) suffering from screw loosening (three at the vertebral level, one at the iliac wing level) after Posterior Lumbar Interbody Fusion (PLIF) treatment was done. The average age was 80 years. Surgical treatment was not indicated or not wished for by the patients. Institutional review board approval and informed consent were obtained. Percutaneous consolidation was performed by an interventional radiologist under CT and fluoroscopy guidance. The path of the trocars was made outside loosened screws bilaterally. Follow-up was assessed using the Visual Analog Scale (VAS). RESULTS: In all cases, bone cement was successfully placed around the loosened screw. The mean volume of cement that was injected was 3 ml. No cement leakage was observed. No neurological complication occurred. Using VAS, pain decreased from more than 9/10 preoperatively to less than 2/10 the day after the procedure for all patients (p < 0.05). CONCLUSION: This study suggests that loosening of spine arthrodesis could be successfully treated by percutaneous injection of bone cement under CT and fluoroscopy guidance. KEY POINTS: • PLIF is one of the surgical techniques for spinal arthrodesis. • Treatment indications are degenerative disease or instability following trauma, tumour, or infection. • Screw loosening is a frequent complication that can occur after surgery. • Percutaneous facet consolidation under dual guidance seems to be a feasible technique. • The procedure is performed under local anaesthesia using a minimally invasive approach.

CT scan-guided percutaneous osteosynthesis of a complex, multifocal fracture of the pelvic girdle in a 14-year-old adolescent.

We report on a 14-year-old girl with minimally displaced pelvic girdle and acetabular roof fracture following motor vehicle trauma, treated percutaneously under CT and C-arm fluoroscopic guidance by an interventional radiologist. After informed consent from the patient's parents, under surgical aseptic conditions and under general anesthesia, three screws were positioned adequately under dual guidance by a radiologist and without immediate or long-term complication. The patient was mobilized 48 h after the procedure and resumed normal activities after 1 month. Even though the technique has been described before on adults, to our knowledge this is the first time it has been described on a pediatric patient.