•Artificial intelligence is used for assessing response to therapy in rectal cancer.•Textural features extraction from high resolution 3 T MR images.•Artificial intelligence model helps personalize ...therapeutic strategy.•Decisions curves analysis confirm clinical utility.
To develop and validate an Artificial Intelligence (AI) model based on texture analysis of high-resolution T2 weighted MR images able 1) to predict pathologic Complete Response (CR) and 2) to identify non-responders (NR) among patients with locally-advanced rectal cancer (LARC) after receiving neoadjuvant chemoradiotherapy (CRT).
Fifty-five consecutive patients with LARC were retrospectively enrolled in this study. Patients underwent 3 T Magnetic Resonance Imaging (MRI) acquiring T2-weighted images before, during and after CRT. All patients underwent complete surgical resection and histopathology was the gold standard. Textural features were automatically extracted using an open-source software. A sub-set of statistically significant textural features was selected and two AI models were built by training a Random Forest (RF) classifier on 28 patients (training cohort). Model performances were estimated on 27 patients (validation cohort) using a ROC curve and a decision curve analysis.
Sixteen of 55 patients achieved CR. The AI model for CR classification showed good discrimination power with mean area under the receiver operating curve (AUC) of 0.86 (95% CI: 0.70, 0.94) in the validation cohort. The discriminatory power for the NR classification showed a mean AUC of 0.83 (95% CI: 0.71,0.92). Decision curve analysis confirmed higher net patient benefit when using AI models compared to standard-of-care.
AI models based on textural features of MR images of patients with LARC may help to identify patients who will show CR at the end of treatment and those who will not respond to therapy (NR) at an early stage of the treatment.
The present study describes the technique and results of proximal row carpectomy with resection of the head of the capitate and replacement with a pyrocarbon capitate resurfacing implant. The major ...indication for surgical treatment was arthritic changes on the head of the capitate. Patients were assessed by range of motion, grip strength, pain and functional scoring, and radiographic studies. In most patients, wrist function was improved and pain relief was obtained. This surgical procedure may represent a good alternative to total and partial wrist arthrodesis.
The background induced by the high penetration power of the radiation is the main limiting factor of the current radio-guided surgery (RGS). To partially mitigate it, a RGS with β(+)-emitting ...radio-tracers has been suggested in literature. Here we propose the use of β(-)-emitting radio-tracers and β(-) probes and discuss the advantage of this method with respect to the previously explored ones: the electron low penetration power allows for simple and versatile probes and could extend RGS to tumours for which background originating from nearby healthy tissue makes probes less effective. We developed a β(-) probe prototype and studied its performances on phantoms. By means of a detailed simulation we have also extrapolated the results to estimate the performances in a realistic case of meningioma, pathology which is going to be our first in-vivo test case. A good sensitivity to residuals down to 0.1 ml can be reached within 1 s with an administered activity smaller than those for PET-scans thus making the radiation exposure to medical personnel negligible.
Kienböck disease is an aseptic osteonecrosis of the lunate, which gradually leads to total carpal collapse. Lichtman's classification relates radiographic evidence of wrist damage to four different ...stages and supports surgical decision-making. This study pertains to six patients (2 males and 4 females) affected by stage IV Kienböck's disease who underwent proximal row carpectomy and received an RCPI implant. The clinical outcomes consisted of wrist range of motion (ROM), pain on a VAS scale (0–10), the DASH score and the patient's level of satisfaction. The mean follow-up was 27.6 months (16–36). Pain relief and improvements in wrist flexion – extension ROM, radial – ulnar deviation and strength were achieved in every patient. There were no cases of implant failure or dislocation. Considering the good results obtained, we believe that proximal row carpectomy associated with the use of a pyrocarbon RCPI implant is a valid surgical technique for the treatment of stage IV Kienböck's disease. It is a good alternative to carpal fusion, which leads to wrist immobility, and to total wrist joint replacement, which has a high incidence of dislocation and fracture.
La maladie de Kienböck est caractérisée par une nécrose du lunatum qui comporte un collapsus progressif du carpe. La classification de Lichtman range les différentes altérations radiologiques du lunatum en 4 stades évolutifs sur la base desquels différents traitement sont proposés. Les auteurs rapportent leur expérience relative à 6 patients (2 hommes et 4 femmes), affectés par la maladie de Kienböck au IV stade de la classification de Lichtman, traités par résection de la rangée proximale du carpe et l’utilisation de l’implant RCPI. Pour l’évaluation des résultats cliniques, ont été étudiés la mobilité du poignet, la force de prise mesurée avec le dynamomètre Jamar, la douleur évaluée sur une échelle visuelle analogique (VAS 0-10), le score DASH et le degré de satisfaction du malade. Tous les patients ont été contrôlés avec un recul moyen de 27,6 mois (de 16 à 36 mois). Les résultats cliniques étaient bons chez tous les patients, avec une réduction notable de la symptomatologie douloureuse et une amélioration de la mobilité et de la force du poignet. Les résultats radiologiques étaient également bons sans rupture ni luxation de l’implant prothétique. En raison des bons résultats obtenus, nous pensons que la résection de la rangée proximale du carpe associée à l’utilisation de la prothèse en pyrocarbone RCPI représente une technique chirurgicale valable et représente une bonne alternative à l’arthrodèse du carpe, qui bloque tous les mouvements du poignet, et à la mise en place d’une prothèse totale de poignet, qui présente un risque élevé de luxation ou de rupture.
Organic scintillators are often chosen as radiation detectors for their fast decay time and their low Z, while inorganic ones are used when high light yields are required. In this paper we show that ...a para-terphenyl based detector has a blend of properties of the two categories that can be optimal for energy and position measurements of low-energy charged particles. Using 0.1% diphenylbutadiene doped para-terphenyl samples we measured a light attenuation length λ = 4.73 ±0.06 mm, a quenching factor for α particles Q α = (10.7 ±0.6), and a rejection power ranging between 3 - 11% for 660 keV photons, with respect to electrons of the same energy, depending on the signal threshold. A simulation based on FLUKA properly reproduces the experimental data distributions.
We report the outcomes of an arthroscopic-assisted minimally invasive technique to reconstruct the scapho-lunate ligament using a bone–ligament–bone graft in 11 patients (11 wrists). The mean ...follow-up time was 29 months (range 20 to 38). The preoperative mean wrist flexion, extension, grip strength and patient-rated wrist evaluation score values were 61°, 54°, 115 N and 54, respectively. The postoperative mean values were 64°, 58°, 142 N and 15, respectively. There were no statistical differences between the pre- and postoperative wrist flexion and extension, whereas changes in grip strength and patient-rated wrist evaluation score were significant. Scapho-lunate angles decreased significantly from 69° to 60°. Based on our clinical outcomes, this method provides a reliable alterative for the reconstruction of the scapho-lunate ligament in patients with persistent Geissler type 3 and 4 lesions in the short-term.
Level of evidence: IV
In hand disorders surgical procedures are more and more widely used and often it's necessary to approach the wrist by the dorsal way. Beneath anatomy of this region is well known, there is still room ...enough to develop new surgical exposure techniques mostly related to physiology and biomechanics. Our goals are to present an innovative surgical dorsal exposure of the wrist, to show its use for different problems solving, and to evaluate its mini-invasive and functional outcome. Our inedited surgical technique is presented. Since November 1999 to February 2008, this technique has been used by the same surgeon in 60 cases for different pathologies and procedures: 14 SNAC-SLAC wrists III-IV treated by proximal row resection and Resurface-Capitate Pyrocarbon Implant (RCPI), 2 Fenton syndromes by bone graft and RCPI, 6 SNACSLAC II by proximal row resection +/- radial styloidectomy, 2 SLAC III by scaphoidectomy and capito-lunate arthrodesis, 12 scapho-lunate recent dissociations by ligamentoplasty (double approach), 4 scapho-lunate inveterate dissociations by Cuenod Saffar-Romano modified technique and 4 by synthetic ligaments, 1 fracture of the scaphoid proximal pole by synthesis-revascularization-S.L.ligament reconstruction, 15 Kienbock's diseases revascularized by II m.c. artery +/- radial osteotomy. Patients have been evaluated at follow up through the DASH disability questionnaire, the Mayo score for the force, ROM, pain, satisfaction grade. Results are good and encouraging for these applications. In conclusion this new technique with its limited exposure permits an early mobilization with a lower risk of stiffness and can be considered mini-invasive.
•Test on radiomarked ex-vivo meningioma specimens confirmed feasibility of β-RGS.•Personalized minimal activity to be injected can be evaluated from PET images.•Effective dose is at a level of ...whole-body PET/CT and personnel exposure negligible.
Radio-guided surgery with β- decays is a novel technique under investigation. One of the main advantages is its capability to detect small (⩽0.1 ml) samples after injecting the patient with low activity of radiopharmaceutical. This paper presents an experimental method to quantify this feature based on ex-vivo tests on specimens from meningioma patients.
Patients were enrolled on the basis of the standard uptake value (SUV) and the tumour-to-non-tumour activity ratio (TNR) resulted from 68Ga-DOTATOC PET exams. After injecting the patients with 93–167 MBq of 90Y-DOTATOC, 26 samples excised during surgery were analyzed with a β- probe. The radioactivity expected on the neoplastic specimens was estimated according to the SUV found in the PET scan and the correlation with the measured counts was studied. The doses to surgeon and medical personnel were also evaluated.
Even injecting as low as 1.4 MBq/kg of radiotracer, tumour residuals of 0.1 ml can be detected. A negligible dose to the medical personnel was confirmed.
Radio-guided surgery with β- decays is a feasible technique with a low radiation dose for both personnel and patient, in particular if the patient is injected with the minimum required activity. A correlation greater than 80% was observed between the measured counts and the expected activity for the lesion samples based on the individual SUV and the TNR. This makes identifiable the minimum injectable radiotracer activity for cases where 90Y is the utilized radionuclide.
Highlights • A novel radio-guided-surgery technique using beta- radiation is under development. • Simulations and lab tests demonstrated its potential compared to state-of-the-art. • A ...proof-of-principle test on patient confirmed tracer uptake and probe sensitivity. • It also confirmed that the dose delivered to the medical staff is negligible. • This is a proof-of-principle, not a case report, nor a clinical trial.
PDF
