Interpretation Of Computed Tomography Images Research Articles

Accurate preoperative staging and HER2 status prediction of gastric cancer by the deep learning system based on enhanced computed tomography.

To construct the deep learning system (DLS) based on enhanced computed tomography (CT) images for preoperative prediction of staging and human epidermal growth factor receptor 2 (HER2) status in gastric cancer patients. The raw enhanced CT image dataset consisted of CT images of 389 patients in the retrospective cohort, The Cancer Imaging Archive (TCIA) cohort, and the prospective cohort. DLS was developed by transfer learning for tumor detection, staging, and HER2 status prediction. The pre-trained Yolov5, EfficientNet, EfficientNetV2, Vision Transformer (VIT), and Swin Transformer (SWT) were studied. The tumor detection and staging dataset consisted of 4860 enhanced CT images and annotated tumor bounding boxes. The HER2 state prediction dataset consisted of 38900 enhanced CT images. The DetectionNet based on Yolov5 realized tumor detection and staging and achieved a mean Average Precision (IoU=0.5) (mAP_0.5) of 0.909 in the external validation cohort. The VIT-based PredictionNet performed optimally in HER2 status prediction with the area under the receiver operating characteristics curve (AUC) of 0.9721 and 0.9995 in the TCIA cohort and prospective cohort, respectively. DLS included DetectionNet and PredictionNet had shown excellent performance in CT image interpretation. This study developed the enhanced CT-based DLS to preoperatively predict the stage and HER2 status of gastric cancer patients, which will help in choosing the appropriate treatment to improve the survival of gastric cancer patients.

Use of Chinese Visible Human Images to Enhance the Interpretation of CT or MRI Images: Application to Nasopharyngeal Structures Segmentation in the Treatment Planning System

Background: With leading morbidity among malignant tumors in otorhinolaryngology, Nasopharyngeal carcinoma (NPC) is one of the most frequent malignant tumors in China. Objectives: This study aimed to help radiotherapy doctors recognize and segment nasopharyngeal organs at risk of NPC and make a radiotherapy plan. Methods: The authors used B-spline and mutual information to transform, register, and fuse Chinese Visible Human images with the volunteer’s personalized computed tomography (CT) images, and integrated them into the Treatment Planning System (TPS). Consequently, Three-Dimensional Visualization Treatment Planning System (3DV+TPS) was created. To verify it, 3DV+TPS was deployed to identify and segment the nasopharyngeal organs at risk of NPC, and a questionnaire was filled out by radiotherapy doctors. Results: Results showed that 3DV+TPS can finish the registration and fusion of four sets of sectional anatomical images and individual CT images of volunteers in approximately 3 min and 50 sec. Conclusion: The registered and fused images can accurately reflect the position, outline, and adjacent space of the nasopharyngeal structure which is not clear in CT images. Therefore, it is helpful for recognizing and segmenting neural, muscular, and glandular structures. Through automatically registering and fusing color and CT gray images, 3DV+TPS improves the accuracy and efficiency of recognizing nasopharyngeal structures in making radiotherapy plans. It is also useful to improve the teaching quality of tumor radiotherapy for medical students and interns as well.

Evaluation of Intracranial Hypertension in Patients With Hypertensive Intracerebral Hemorrhage Using Texture Analysis.

PurposeTexture analysis based on clinical images had been widely used in neurological diseases. This study aimed to achieve depth information of computed tomography (CT) images by texture analysis and to establish a model for noninvasive evaluation of intracranial pressure (ICP) in patients with hypertensive intracerebral hemorrhage (HICH).MethodsForty-seven patients with HICH were selected. Related CT images and ICP value were collected. The morphological features of hematoma volume, midline shift, and ventriculocranial ratio were measured. Forty textural features were extracted from regions of interest. Four models were established to predict intracranial hypertension with morphological features, textural features of anterior horn, textural features of temporal lobe, and textural features of posterior horn.ResultsModel of posterior horn had the highest ability to predict intracranial hypertension (AUC = 0.90, F1 score = 0.72), followed by model of anterior horn (AUC = 0.70, F1 score = 0.53) and model of temporal lobe (AUC = 0.70, F1 score = 0.58), and model of morphological features displayed the worst performance (AUC = 0.42, F1 score = 0.38).ConclusionTexture analysis can realize interpretation of CT images in depth, which has great potential in noninvasive evaluation of intracranial hypertension.

Diagnostic Performance of MRI Versus CT in the Evaluation of Intra-articular Osteochondral Fracture in Pediatric Patients With Acute Traumatic Lateral Patellar Dislocation.

Background:Evaluation of intra-articular osteochondral fractures in children with acute traumatic lateral patellar dislocation (LPD) is important for determining treatment options.Purpose:To (1) compare the diagnostic accuracy of computed tomography (CT) and magnetic resonance imaging (MRI) for evaluating intra-articular osteochondral fractures; (2) compare the interpretation of CT and MRI images between radiologists and pediatric orthopaedic surgeons (POS); and (3) investigate any clinical factors influencing the accuracy of CT and MRI evaluations.Study Design:Cohort study (diagnosis); Level of evidence, 2.Methods:We reviewed 35 knees in 35 patients (mean age, 12.2 ± 1.2 years; 12 boys and 23 girls) who were treated arthroscopically for acute traumatic LPD; 71% of the patients had patellar fractures, 54% had femoral fractures, and 60% had free osteochondral fracture fragments. All presurgical MRI and CT images were reviewed by POS who were blinded to both the reports of the radiologists and surgical records. We compared the accuracy of CT and MRI in diagnosing intra-articular osteochondral fractures against the arthroscopic findings and compared the interpretation of the images by the POS (MRI-O, CT-O) with those of the radiologists (MRI-R, CT-R).Results:There was no significant difference in diagnostic accuracy between CT and MRI for overall intra-articular osteochondral fractures by the POS or the radiologists; however, the CT-O images had a higher diagnostic specificity (84.2% vs 69.6%; P < .001) and sensitivity (88.1% vs 70.1%; P < .001) versus the MRI-R images. Regarding free fracture fragments, the CT-R images had a higher diagnostic accuracy than the MRI-R images (73.5% vs 47.1%; P = .026). When backed by clinical data, the MRI-O images had greater diagnostic accuracy (78.7% vs 60.3%; P = .001) and sensitivity (88.1% vs 30.7%; P = .021) but lower specificity compared with the MRI-R images, and the CT-O images had similar diagnostic accuracy but greater sensitivity than the CT-R images (70.1% vs 52.2%; P < .001). The diagnostic accuracy of MRI-O images was lower for children under 12 years versus children 12 years and over (67.5% vs 83.3%; P = .040).Conclusion:Compared with MRI, CT scans had better diagnostic performance in the evaluation of intra-articular osteochondral fractures in pediatric patients with acute traumatic LPD. Clinical data enhanced the diagnostic sensitivity of MRI and CT but decreased the specificity of MRI. MRI evaluations remain challenging for both POS and radiologists.

Importance of Radiologists in Optimizing Outcomes for Older Americans with Acute Abdomen

BackgroundPatients presenting with acute abdominal pain often undergo a computed tomography (CT) scan as part of their diagnostic workup. We investigated the relationship between availability, timeliness, and interpretation of CT imaging and outcomes for life-threatening intra-abdominal diseases or “acute abdomen,” in older Americans. MethodsData from a 2015 national survey of 2811 hospitals regarding emergency general surgery structures and processes (60.1% overall response, n = 1690) were linked to 2015 Medicare inpatient claims data. We identified beneficiaries aged ≥65 admitted emergently with a confirmatory acute abdomen diagnosis code and operative intervention on the same calendar date. Multivariable regression models adjusted for significant covariates determined odds of complications and mortality based on CT resources. ResultsWe identified 9125 patients with acute abdomen treated at 1253 hospitals, of which 78% had ≥64-slice CT scanners and 85% had 24/7 CT technicians. Overnight CT reads were provided by in-house radiologists at 14% of hospitals and by teleradiologists at 66%. Patients were predominantly 65-74 y old (43%), white (88%), females (60%), and with ≥3 comorbidities (67%) and 8.6% died. STAT radiology reads by a board-certified radiologist rarely/never available in 2 h was associated with increased odds of systemic complication and mortality (adjusted odds ratio 2.6 [1.3-5.4] and 2.3 [1.1-4.8], respectively). ConclusionsDelays obtaining results are associated with adverse outcomes in older patients with acute abdomen. This may be due to delays in surgical consultation and time to source control while waiting for imaging results. Processes to ensure timely interpretation of CT scans in patients with abdominal pain may improve outcomes in high-risk patients.

Sectional Anatomy Quiz - VI.

This quiz is part of a series which aims to aid nuclear physicians in interpreting the computed tomography (CT) component of the single photon emission computed tomography (SPECT) and positron emission tomography (PET) studies. The current quiz includes normal and pathological axial CT images at the level of the superior mesenteric artery (SMA) and superior mesenteric vein (SMV). The SMV is normally located to the right of the SMA and is of a larger caliber. Various pathologies such as malignancy, infection or vascular disease can alter the position and/or appearance of the SMA, SMV and the surrounding anatomical structures present at this level. Understanding how normal anatomy is altered by pathology at this level will facilitate improved interpretation of abdominal CT images.

X-Ray Dark-Field Chest Imaging Can Detect and Quantify Emphysema in COPD Patients

Background: Diseases of the respiratory system are leading global causes of chronic morbidity and mortality. While advanced medical imaging technologies of today deliver detailed diagnostic information, a low-dose, fast, and inexpensive option for early detection and/or follow-ups is still lacking. Here, we report on the first human application of a novel modality, namely X-ray dark-field chest imaging, which might fill this gap. Enabling the assessment of microstructural changes in lung parenchyma, this technique presents a more sensitive alternative to conventional chest X-rays, and yet requires only a fraction of the dose applied in computed tomography (CT). Methods: For this first clinical evaluation, we have built a novel dark-field chest X-ray system, which is also capable of simultaneously acquiring a conventional thorax radiograph (7 seconds, 0·035 mSv effective dose). Representing a major medical condition, we selected chronic obstructive pulmonary disease as study subject to obtain a first impression of potential diagnostic benefits relevant to humans. For a collective of 77 patients with different disease stages, X-ray dark-field- and CT-images were acquired and visually assessed by 5 readers. In addition, pulmonary function tests were performed for every patient. The individual data sets were evaluated in a statistical work-up using correlation testing, rank-based analysis of variance, and pair-wise post-hoc comparison. Findings: Compared to CT-based parameters (quantitative emphysema: ρ=–0·27, p=0·0893 and visual emphysema: ρ=–0·45, p=0·0028), the dark-field signal (ρ=0·62, p<0·0001) yields a stronger correlation with diffusion capacity in the evaluated collective. Emphysema assessment based on dark-field chest X-ray features yields consistent conclusions with findings from visual CT image interpretation and shows improved diagnostic performance in comparison to conventional clinical tests characterizing emphysema. Interpretation: X-ray dark-field chest imaging allows the diagnosis of pulmonary emphysema as it provides relevant information representing the structural condition of lung parenchyma. Significant diagnostic benefits are also expected for other lung disorders. Funding Statement: We acknowledge financial support through the European Research Council, Royal Philips, Karlsruhe Nano Micro Facility. Declaration of Interests: T.K., A.Y., and T.P. are employees of Royal Philips. The remaining authors declare no competing interests. Ethics Approval Statement: The study was approved by the institutional ethics review board and the German Federal Office for Radiation Protection (Bundesamt fur Strahlenschutz, BfS) and the permission from authorities to operate the demonstrator system for first human applications was obtained. All participants gave written informed consent.

A Shallow Convolutional Neural Network Predicts Prognosis of Lung Cancer Patients in Multi-Institutional CT-Image Data.

Lung cancer is the most common fatal malignancy in adults worldwide, and non-small cell lung cancer (NSCLC) accounts for 85% of lung cancer diagnoses. Computed tomography (CT) is routinely used in clinical practice to determine lung cancer treatment and assess prognosis. Here, we developed LungNet, a shallow convolutional neural network for predicting outcomes of NSCLC patients. We trained and evaluated LungNet on four independent cohorts of NSCLC patients from four medical centers: Stanford Hospital (n = 129), H. Lee Moffitt Cancer Center and Research Institute (n = 185), MAASTRO Clinic (n = 311) and Charité – Universitätsmedizin (n=84). We show that outcomes from LungNet are predictive of overall survival in all four independent survival cohorts as measured by concordance indices of 0.62, 0.62, 0.62 and 0.58 on cohorts 1, 2, 3, and 4, respectively. Further, the survival model can be used, via transfer learning, for classifying benign vs malignant nodules on the Lung Image Database Consortium (n = 1010), with improved performance (AUC=0.85) versus training from scratch (AUC=0.82). LungNet can be used as a noninvasive predictor for prognosis in NSCLC patients and can facilitate interpretation of CT images for lung cancer stratification and prognostication.

PET/MRI-guided GTV delineation during radiotherapy planning in patients with squamous cell carcinoma of the tongue

PurposeThe aim of the study was to evaluate the usefulness and accuracy of 18-fluorine-labeled fluorodeoxyglucose (PET) and magnetic resonance imaging (MRI) hybrid in gross tumor volume (GTV) delineation during radiotherapy planning in patients with carcinoma of the tongue.MethodsTen patients with squamous cell carcinoma (SCC) of the tongue underwent computed tomography (CT) and PET/MRI examination. The GTV for primary tumor and lymph nodes (nGTV) were defined on CT (GTV-CT) and compared to GTVs obtained from PET (GTV-PET) and MRI (GTV-MRI) images. Two methods of GTV determination were used: visual interpretation of CT, PET (GTV-PETvis) and MRI images and quantitative automatic method (Syngovia, Siemens) based on a chosen threshold value (20%, 30%, 40%, 50%) of standardized uptake values (SUVmax) from PET examination (GTV-PET20%, GTV-PET30%, etc.). Statistical analysis of differences in GTV values obtained from CT, PET and MRI studies was performed. GTV-CT was used as a reference.ResultsIn all, 80% of GTV-MRI and 40% of GTV-PETvis were larger than GTV-CT. Respectively, 20% of GTV-MRI and 60% of GTV-PETvis were smaller than GTV-CT. Taking into account all threshold measurements, 70% of volumes were smaller than GTV-CT. GTV-PET30% were the most closely related volumes to GTV-CT from all threshold methods in 50% of patients. GTV-PETvis generated the most similar volumes in relation to GTV-CT from all PET measurements. Statistical analysis confirmed those results. Compared to nGTV-CT, 70% of nGTV-MRI and 20% of nGTV-PETvis were larger. The remaining nGTV-MRI and nGTV-PETvis measurements were smaller than nGTV-CT. Measurements of all thresholds nGTVs were smaller than nGTV-CTV in 52.5% of cases. nGTV-PET20% were the most closely related volumes to nGTV-CT in 40% of the cases. Statistical analysis showed that nGTV-PET20% (p = 0.0468), nGTV-PETvis (p = 0.0166), and nGTV-PET50% (p = 0.0166) diverge significantly from nGTV-CT results. nGTV-MRI (p = 0.1141), nGTV-PET30% (p = 0.2845), and nGTV-PET40% (p = 0.5076) were significantly related with nGTV-CT.ConclusionCombination of PET/MRI provides more information during target tumor mass delineation in radiotherapy planning of patients with SCC of the tongue than other standard imaging methods. The most frequently matching threshold value was 30% of SUVmax for primary tumor delineation and 30–40% of SUVmax for nGTV determination.

CT findings after pelvic exenteration: review of normal appearances and most common complications.

The aim of this review is to illustrate normal computed tomography (CT) findings and the most common complications in patients who underwent pelvic exenteration (PE) for advanced, persistent or recurrent gynecological cancers. We review the various surgical techniques used in PE, discuss optimal CT protocols for postsurgical evaluation and describe cross-sectional imaging appearances of normal postoperative anatomic changes as well as early and late complications. The interpretation of abdominopelvic CT imaging after PE is very challenging due to remarkable modifications of normal anatomy. After this radical pelvic surgery, the familiarity with expected CT appearances is crucial for diagnosis and appropriate management of potentially life-threatening complications in patients who underwent PE.

Variation of canine vertebral bone architecture in computed tomography.

Focal vertebral bone density changes were assessed in vertebral computed tomography (CT) images obtained from clinically healthy dogs without diseases that affect bone density. The number, location, and density of lesions were determined. A total of 429 vertebral CT images from 20 dogs were reviewed, and 99 focal vertebral changes were identified in 14 dogs. Focal vertebral bone density changes were mainly found in thoracic vertebrae (29.6%) as hyperattenuating (86.9%) lesions. All focal vertebral changes were observed at the vertebral body, except for a single hyperattenuating change in one thoracic transverse process. Among the hyperattenuating changes, multifocal changes (53.5%) were more common than single changes (46.5%). Most of the hypoattenuating changes were single (92.3%). Eight dogs, 40% of the 20 dogs in the study and 61.6% of the 13 dogs showing focal vertebral changes in the thoracic vertebra, had hyperattenuating changes at the 7th or 8th thoracic vertebra. Our results indicate that focal changes in vertebral bone density are commonly identified on vertebral CT images in healthy dogs, and these changes should be taken into consideration on interpretation of CT images.

Cranioplasty Using Titanium Mesh After Skull Tumor Resection in Five Dogs.

To describe the clinical details, surgery, postoperative imaging, and short to mid-term outcome after cranioplasty with titanium mesh in dogs with large skull tumors. Case series. Client-owned dogs with skull tumors (n=5). All tumors were removed via craniectomy and a sheet of titanium mesh was contoured to reconstruct the calvarial defect and sutured to surrounding musculature. Four dogs had multilobular tumors of bone and 1 dog had a soft tissue sarcoma invading the cranial vault. Neurologic examination was unchanged or improved postoperative, a good cosmetic appearance was achieved, and no complications were noted at 2 weeks postoperative. Late postoperative computed tomography (CT) in 2 dogs and magnetic resonance (MR) imaging in 1 dog confirmed the presence of the titanium mesh without migration. There was no interference of the mesh with image interpretation and definitive radiation therapy was pursued in 1 dog without complication. Late follow-up reported 2 dogs euthanatized; at 44 weeks postoperative due to tumor re-growth; at 12 weeks postoperative for hemoabdomen, respectively. One dog drowned at 40 weeks postoperative, 1 dog was lost to follow-up, and 1 dog is alive at 83 weeks postoperative free of clinical signs. Titanium mesh is suitable for cranioplasty based on its strength, biocompatibility, and excellent handling characteristics. It does not interfere with acquisition or interpretation of CT or MR images, thereby allowing postoperative imaging for ongoing assessment.

Automatic classification of lung tumour heterogeneity according to a visual-based score system in dynamic contrast enhanced CT sequences

Computed tomography (CT) technologies have been considered for a long time as one of the most effective medical imaging tools for morphological analysis of body parts. Contrast Enhanced CT (CE-CT) also allows emphasising details of tissue structures whose heterogeneity, inspected through visual analysis, conveys crucial information regarding diagnosis and prognosis in several clinical pathologies. Recently, Dynamic CE-CT (DCE-CT) has emerged as a promising technique to perform also functional hemodynamic studies, with wide applications in the oncologic field. DCE-CT is based on repeated scans over time performed after intravenous administration of contrast agent, in order to study the temporal evolution of the tracer in 3D tumour tissue. DCE-CT pushes towards an intensive use of computers to provide automatically quantitative information to be used directly in clinical practice. This requires that visual analysis, representing the gold-standard for CT image interpretation, gains objectivity. This work presents the first automatic approach to quantify and classify the lung tumour heterogeneities based on DCE-CT image sequences, so as it is performed through visual analysis by experts. The approach developed relies on the spatio-temporal indices we devised, which also allow exploiting temporal data that enrich the knowledge of the tissue heterogeneity by providing information regarding the lesion status.

Early nontumorous CT findings after irreversible electroporation of locally advanced pancreatic cancer.

The use of irreversible electroporation (IRE) has been a relatively recent development in the palliative treatment of locally advanced pancreatic cancer. With CT as a key modality in patient follow-up, recognition of nontumorous imaging findings is paramount after IRE. A retrospective review of patients having undergone IRE for locally advanced pancreatic adenocarcinoma was performed. A total of 36 patients met inclusion criteria and their imaging studies were reviewed by two radiologists. Nontumorous abnormalities identified in the peri-electroporation bed on Computed Tomography (CT) during the early postoperative period (within 30 days) were characterized and classified into categories. Our results indicate that the most common nontumorous findings in the peri-electroporation bed were vascular, followed by changes involving the gastrointestinal tract, peritoneal cavity, and, infrequently, the biliary tree. Interpretation of CT imaging of the postoperative peri-electroporation bed is challenging. This review of CT findings allows the radiologist to recognize and anticipate significant nontumorous findings in the peri-electroporation bed during early follow-up after IRE.

Quantitative Biomedical Imaging: Techniques and Clinical Applications.

Quantitative Biomedical Imaging: Techniques and Clinical Applications.

MORPHOLOGICAL VARIATIONS OF CAUDATE LOBE OF THE LIVER AND THEIR CLINICAL IMPLICATIONS

Address for Correspondence: Dr. Sarala HS, Department of Anatomy, Bangalore medical college and research institute, Bangalore-560002. Karnataka, India. Mobile No.: +919886060508 E-Mail: drsaralahs@yahoo.co.in *1 Tutor, M D Anatomy, Department of Anatomy, Bangalore medical college and research institute, Bangalore. 2 Associate professor, Department of Anatomy, Kempegowda institute of medical sciences, Bangalore. 3 Professor & HOD, Department of Anatomy, Kempegowda institute of medical sciences, Bangalore. Background: Knowledge of normal and variant anatomy of the caudate lobe of the liver is a prerequisite for better surgical outcome. Morphology of the caudate lobe has significance in diagnostic imaging and also minimally invasive surgical approaches. So we have taken up this study to know the detailed morphology of the caudate lobe. Materials and methods: The morphology of caudate lobe was studied in 100 formalin fixed adult livers obtained from the department of anatomy, Kempegowda institute of medical sciences and Bangalore medical college, Bangalore. The livers were studied for the morphological variations of the caudate lobe. Results: Various shapes of the caudate lobe were noticed. Vertical fissure extending upwards from lower border was seen in 30%. Prominent papillary process was seen in 21%. Prominent caudate process was seen in 9%. Discussion: Various shapes of the caudate lobe were encountered in the present study. Sahni et al and Joshi SD et al also reported a variety of shapes of the caudate lobe. Vertical fissure extending upwards from the inferior border was seen in 30% of the livers. Kogure et al noticed the notch in approximately half of the patients undergoing hepatectomy. Kogure et al also noted that the external notch may be a vestige of the portal segmentation of the caudate lobe. Prominent papillary process was observed in 21% of the livers. Joshi SD et al have also found prominent papillary process in 33% of the livers in their study. Auh et al observed that on CT (Computed Tomography), a normal or small papillary process may be mistaken for enlarged porta hepatis lymph nodes. When enlarged papillary process extends on to left side it can mimic pancreatic body mass. Conclusion: The incidence of morphological variations of caudate lobe is very high in this study. The papillary process of caudate lobe is a potential source of pitfalls in interpretation of CT images at and just below the porta hepatis. Knowledge of these variations is important for radiologists to achieve correct diagnosis and for surgeons to plan for surgery and to achieve good surgical outcome.

Postharvest noninvasive assessment of fresh chestnut (Castanea spp.) internal decay using computer tomography images

X-ray computed tomography (CT) is an effective noninvasive tool to visualize fresh agricultural commodities’ internal components and quality attributes, including those of chestnuts (Castanea spp). There is no procedure to automatically, effectively and efficiently classify fresh commodities from a continuous inline flow through a CT system. If the information obtained by CT scanning of fresh agricultural commodities is to be used in an industrial application (e.g. inline sorting), automated interpretation of CT images is essential. For this purpose, an image analysis method (algorithm) for the automatic classification of CT images obtained from 2848 fresh chestnuts (cv. ‘Colossal’ and ‘Chinese seedlings’), during the harvesting years from 2009 to 2012, was developed and tested. Classification accuracy was evaluated by comparing the classes obtained from six CT images per chestnut to their internal quality assessment. An experienced human rater performed internal quality assessment by visually and invasively rating fresh chestnut internal decay severity (quality) into 5-, 3- and 2-classes.After CT image preprocessing, cropping and segmentation, 1194 grayscale intensity and textural features were extracted from six resultant CT images per sample. Relevant features were selected using a sequential forward selection algorithm with the Fisher discriminant objective function. 86, 155 and 126 features were effective in designing a quadratic discriminant classifier with a 4-fold cross-validation with a performance accuracy of 85.9%, 91.2% and 96.1% for 5, 3 and 2 classes, respectively. This method is accurate and objective in determining fresh chestnut internal quality, and the methodology is applicable to automatic noninvasive inline CT sorting system development.

Measurement of knot width in CT images of Norway spruce (Picea abies [L.] Karst.)—Evaluating the accuracy of an image analysis method

X-ray computed tomography (CT) is an effective scanning technology for imaging inner roundwood features. It is assumed that using this technology for log inspection prior to the first conversion could further optimise raw material utilisation. If the information obtained by CT scanning of a log shall be exploited in an industrial application, automated interpretation of CT images is a necessity. An image analysis method for knot extraction and measurement was tested on CT images of Norway spruce (Picea abies [L.] Karst.) produced by a prototype of a dedicated roundwood CT scanner. Measurement accuracy was evaluated through a comparison of the computer measurements obtained on single CT slices to reference measurements obtained manually on physical log cross-sections that corresponded to the images treated. In a linear regression established from 119 measurement pairs 68% of the variation of the manually measured knot width could be explained by the variation of the computer measurements. Bias and root mean squared error (RMSE) were 1.7mm and 4mm, respectively. Hence the measurements were generally in accordance, but an overestimation of knot width by the computer vision method was observed. An algorithm for removing bright sapwood areas from the CT images—necessary as a preparation for knot segmentation—has been found to fail at images of logs with partly dried sapwood; this problem was identified as the primary reason for the loss of 28% of the measurements originally to be acquired and for the occurrence of erroneous measurements. It should be investigated whether a modification of this algorithm could enhance the performance and accuracy of the method.

An image of sudden death: utility of routine post-mortem computed tomography scanning in medico-legal autopsy practice

Post-mortem computed tomography (CT) is an established technique at Victorian Institute of Forensic Medicine (VIFM) used to assist pathologists in determining cause and manner of death. It also plays an important role in identification of deceased individuals as exemplified by the 2009 “Black Saturday” Victorian bushfires in which the remains of 164 individuals were subjected to disaster victim identification procedures. CT scanning is now explicitly incorporated into the Victorian Coronial legislation (Coroners Act 2008), and is an important component of the preliminary examination process whereby a pathologist reviews the circumstances of a death, any pre-existing medical history, whole body CT images, the external appearances of the body and expedited (overnight) toxicological screen results, so that a recommendation to the Coroner may be formulated regarding the likely cause of death and necessity for autopsy. This process has seen a reduction in autopsies from a mean of 62% over the last 5 years to 47% of admissions in less than 12 months. VIFM pathologists perform the primary interpretation of CT images in consultation with a radiologist. A process of quality audit has been instituted in order to detect systematic errors in this interpretation, in addition to a structured education programme directed to correct those errors. New imaging techniques, notably whole body CT angiography and dual energy CT have the prospect of even more substantial forensic application.

Improving the false-negative rate of CT in acute appendicitis—Reassessment of CT images by body imaging radiologists: A blinded prospective study

Purpose To compare the accuracy of computed tomography (CT) analyzed by individual radiology staff members and body imaging radiologists in a non-academic teaching hospital for the diagnosis of acute appendicitis. Patients and methods In a prospective study 199 patients with suspected acute appendicitis were examined with unenhanced CT. CT images were pre-operatively analyzed by one of the 12 members of the radiology staff. In a later stage two body imaging radiologist reassessed all CT images without knowledge of the surgical findings and without knowledge of the primary CT diagnosis. The results, independently reported, were correlated with surgical and histopathologic findings. Results In 132 patients (66%) acute appendicitis was found at surgery, in 67 patients (34%) a normal appendix was found. The sensitivity of the primary CT analysis and of the reassessment was 76% and 88%, respectively; the specificity was 84% and 87%; the positive predictive value was 90% and 93%; the negative predictive value was 64% and 78%; and the accuracy was 78% and 87%. Conclusion Reassessment of CT images for acute appendicitis by body imaging radiologists results in a significant improvement of sensitivity, negative predictive value and accuracy. To prevent false-negative interpretation of CT images in acute appendicitis the expertise of the attending radiologist should be considered.