Should I have a whole body CT scan?

This paper describes an approach to accomplish the fast and automatic localization of the different inner organ regions on 3D CT scans. The proposed approach combines object detections and the majority voting technique to achieve the robust and quick organ localization. The basic idea of proposed method is to detect a number of 2D partial appearances of a 3D target region on CT images from multiple body directions, on multiple image scales, by using multiple feature spaces, and vote all the 2D detecting results back to the 3D image space to statistically decide one 3D bounding rectangle of the target organ. Ensemble learning was used to train the multiple 2D detectors based on template matching on local binary patterns and Haar-like feature spaces. A collaborative voting was used to decide the corner coordinates of the 3D bounding rectangle of the target organ region based on the coordinate histograms from detection results in three body directions. Since the architecture of the proposed method (multiple independent detections connected to a majority voting) naturally fits the parallel computing paradigm and multi-core CPU hardware, the proposed algorithm was easy to achieve a high computational efficiently for the organ localizations on a whole body CT scan by using general-purpose computers. We applied this approach to localization of 12 kinds of major organ regions independently on 1,300 torso CT scans. In our experiments, we randomly selected 300 CT scans (with human indicated organ and tissue locations) for training, and then, applied the proposed approach with the training results to localize each of the target regions on the other 1,000 CT scans for the performance testing. The experimental results showed the possibility of the proposed approach to automatically locate different kinds of organs on the whole body CT scans.

To design multidisease classifiers for body CT scans for three different organ systems using automatically extracted labels from radiology text reports. This retrospective study included a total of 12 092 patients (mean age, 57 years ± 18 [standard deviation]; 6172 women) for model development and testing. Rule-based algorithms were used to extract 19 225 disease labels from 13 667 body CT scans performed between 2012 and 2017. Using a three-dimensional DenseVNet, three organ systems were segmented: lungs and pleura, liver and gallbladder, and kidneys and ureters. For each organ system, a three-dimensional convolutional neural network classified each as no apparent disease or for the presence of four common diseases, for a total of 15 different labels across all three models. Testing was performed on a subset of 2158 CT volumes relative to 2875 manually derived reference labels from 2133 patients (mean age, 58 years ± 18; 1079 women). Performance was reported as area under the receiver operating characteristic curve (AUC), with 95% CIs calculated using the DeLong method. Manual validation of the extracted labels confirmed 91%-99% accuracy across the 15 different labels. AUCs for lungs and pleura labels were as follows: atelectasis, 0.77 (95% CI: 0.74, 0.81); nodule, 0.65 (95% CI: 0.61, 0.69); emphysema, 0.89 (95% CI: 0.86, 0.92); effusion, 0.97 (95% CI: 0.96, 0.98); and no apparent disease, 0.89 (95% CI: 0.87, 0.91). AUCs for liver and gallbladder were as follows: hepatobiliary calcification, 0.62 (95% CI: 0.56, 0.67); lesion, 0.73 (95% CI: 0.69, 0.77); dilation, 0.87 (95% CI: 0.84, 0.90); fatty, 0.89 (95% CI: 0.86, 0.92); and no apparent disease, 0.82 (95% CI: 0.78, 0.85). AUCs for kidneys and ureters were as follows: stone, 0.83 (95% CI: 0.79, 0.87); atrophy, 0.92 (95% CI: 0.89, 0.94); lesion, 0.68 (95% CI: 0.64, 0.72); cyst, 0.70 (95% CI: 0.66, 0.73); and no apparent disease, 0.79 (95% CI: 0.75, 0.83). Weakly supervised deep learning models were able to classify diverse diseases in multiple organ systems from CT scans.Keywords: CT, Diagnosis/Classification/Application Domain, Semisupervised Learning, Whole-Body Imaging© RSNA, 2022.

Six hundred patients were prospectively randomized and given either diatrizoate meglumine 60 or iohexol 300 during dynamic contrast-enhanced body CT in order to compare image quality, contrast reactions, and the number of aborted studies or studies in which images had to be repeated. Three hundred two patients received iohexol 300, and 298 patients received diatrizoate meglumine 60. Thirty-nine percent (119/302) of the patients given iohexol 300 and 63% (188/298) of the patients given diatrizoate meglumine 60 had at least one adverse reaction thought to be related to contrast material during, or within 24 hr of, the body CT scan. When reactions of discomfort (heat or warmth, flushing, bad taste) were excluded, 16% (48/302) of the patients who received iohexol and 33% (99/298) of the patients who were given diatrizoate meglumine 60 had at least one adverse reaction. The differences in both types of reactions between the two agents were significant (p less than .001). Among scans evaluated for study quality, 71% (214/302) of the iohexol 300 group and 62% (184/298) of the diatrizoate meglumine 60 group had optimal enhancement (p = .02). However, when the optimal and adequate categories were combined, 301 of 302 patients given iohexol 300 and 292 of 298 patients given diatrizoate meglumine 60 had diagnostic-quality studies (no statistical difference). Studies were not terminated nor were images repeated in 97% (292/302) of the patients given iohexol 300 and in 94% (280/298) of those given diatrizoate meglumine 60. The CT study was repeated because of movement during the contrast injection or aborted because of contrast-related reactions in 0.7% of the patients given iohexol 300 and in 3.0% of the patients given diatrizoate meglumine 60. This difference was statistically significant (p = .04). Our results suggest that the difference in image quality, number of adverse reactions, and number of aborted/repeated CT scans performed with iohexol 300 or diatrizoate meglumine 60 are not sufficiently different to warrant conversion to nonionic agents for body CT scans.

To investigate a method for selecting a protocol for body CT scan to acquire monochromatic images (MIs) by gemstone spectral imaging (GSI) with or without adaptive statistical iterative reconstruction (ASiR). We subjected a phantom to conventional scanning at 120 kVp and 50-700 mAs and GSI at 165-600 mAs; reconstructed MIs at 65 keV with ASiR 0-100 % for GSI; placed 5 regions of interest on each of 3 consecutive reconstructed slices to obtain the averaged standard deviation (SD) as image noise for conventional scan and GSI. Linear regression analysis yielded the mAs by conventional scan that could be used to achieve similar image noise by GSI. To achieve similar noise, we found excellent linear correlation of mAs between GSI with ASiR 0-100 % and conventional scan (r = 1.00, P < 0.0001), and obtained a table of equivalent mAs between MIs at 65 keV and conventional CT at 120 kVp. We can select a protocol for body CT scan for MIs at 65 keV with or without ASiR with results comparable to those of conventional CT at 120 kVp.

TECHNIQUES FOR COMPUTED TOMOGRAPHY IN INFANTS AND CHILDREN

BackgroundParaneoplastic neurological syndromes constitute rare neurological complications of malignant disease, manifesting in <1% of patients with cancer. Opsoclonus-myoclonus syndrome (OMS) presents with chaotic ocular saccades (opsoclonus), spontaneous muscular jerking (myoclonus) that may be accompanied by ataxia, strabismus, aphasia, or mutism. Its paraneoplastic variant in the adult is most commonly associated with small-cell lung cancer, followed by breast cancer. Importantly, neurological symptoms usually precede the diagnosis of breast cancer and tend to recure after its treatment.Case presentationA 43-year-old premenopausal Caucasian woman with a medical history of hypertension was admitted following an episode of focal seizure. This progressed to generalised tonic-clonic seizures and she was subsequently loaded with phenytoin, valproate, and levetiracetam. Initial workup included whole body CT scan, viral and autoimmune serology. The CT scan revealed an enhancing right axillary lymph node, which in combination with Anti-Ri antibody positivity raised the spectre of paraneoplastic OMS. MRI of the head revealed subtle nonspecific white matter signal change within the centrum semiovale without any mass lesions, while MRI of the spine was unremarkable. An uncomplicated right mastectomy and axillary lymph node clearance was performed: histopathology revealed a 9-mm, grade 2, oestrogen receptor-positive, progesterone receptor-negative (ER8, PR0), Her2-negative invasive ductal carcinoma, and 4/6 positive lymph nodes (T1b N2 M0). Two months later, she was readmitted with vertigo, diplopia, facial weakness, and ataxia, setting the diagnosis anti-Ri syndrome recurrence. MDT recommended mammogram and ultrasound of the left breast, which were normal. Subsequently, four months after initial discharge, she suffered another neurological recurrence; due to concomitant abdominal pain, PET-CT was performed demonstrating a hypermetabolic right ovarian focus. Bilateral salpingo-oophorectomy was performed as per gynaecology MDT and final histology showed normal tubes and ovaries. She has remained on remission since then, with a negative annual mammogram follow-up.ConclusionsIn conclusion, we report a case of OMS associated with breast cancer anti-Ri onconeural antibody. Its manifestations preceded the diagnosis of malignancy and it persisted after cancer treatment, underlining the importance for high clinical suspicion in cases of classical paraneoplastic neurological syndromes as well as the need for long-term clinical follow-up.

Brown tumors are a rare non-neoplastic, osteolytic lesion caused by an increase in osteoclastic bone resorption. The increase in bone breakdown often leads to patients developing hypercalcemia and osteopenia as a result. Hypercalcemia associated with brown tumors arise due to primary, secondary, or tertiary hyperparathyroidism and in rare cases, occur from the development of a parathyroid gland carcinoma. Most cases of brown tumors are asymptomatic, however, on occasion it can present with pain or compressive symptoms. Common sites for these tumors include clavicle, ribs, pelvis, long bones, maxilla, and mandible. Additionally, it should be noted that brown tumors affect trabecular bone more frequently than cancellous bone. We will be looking at a 35-year-old male patient who presented with chest pain. He was investigated thoroughly with blood tests, echocardiogram, coronary angiogram, bone marrow trephine biopsy, whole body CT scan, CT- PET scan and finally with excision rib biopsy. Only upon the excision, rib biopsy was the diagnosis of brown tumor confirmed. The development of this tumor was determined to be secondary to primary hyperparathyroidism. Following surgical treatment for hyperparathyroidism, the brown tumor resolved spontaneously.

Deep learning using electrocardiographs

Primary squamous cell carcinoma of the colon is an extremely rare malignancy. A 48-year-old male visited our hospital for screening colonoscopy. Colonoscopic examination showed a 1 cm sized sessile polyp in the ascending colon. The patient underwent endoscopic mucosal resection (EMR) without any complication. The pathologic findings were compatible with squamous differentiation of tumor cells in inflammatory colonic mucosa. The tumor was confined to the mucosa and the margins of the excised tissue were found to be free of the tumor. There were no other primary sites and no distant metastases in the extensive evaluation using a whole body CT scan and PET-CT. Additional surgical resection was not done. Follow-up colonoscopy performed eight month later showed a whitish scar without evidence of local recurrence and follow-up PET-CT demonstrated no evidence of recurrence. Herein, we report a case of primary squamous cell carcinoma of the ascending colon presenting as a sessile polyp which was removed by EMR.

We report a 68-year-old woman presenting with pain and swelling in her left elbow. An elbow magnetic resonance with gadolinium evidenced bone marrow infiltration and a bone infarct. Given these findings, a body CT scan was performed which showed multiple mesenteric adenopathies and a large retroperitoneal mass. A lymph node biopsy confirmed a B cell lymphoma. Monoarthritis with no systemic manifestations represents a highly uncommon form of presentation of lymphoma. Moreover it usually affects inferior limbs, particularly in the presence of bone infarction.

For gaining a better understanding of bone quality, a great deal of attention has been paid to vertebral geometry in anatomy. The aim of this study was to design a decision support scheme for vertebral geometries. The proposed scheme consists of four parts: (1) automated extraction of bone, (2) generation of median plane image of spine, (3) detection of vertebrae, (4) quantification of vertebral body width, depth, cross-sectional area (CSA), and trabecular bone mineral density (BMD). The proposed scheme was applied to 10 CT cases and compared with manual tracking performed by an anatomy expert. Mean differences in the width, depth, CSA, and trabecular BMD were 3.1 mm, 1.4 mm, 88.7 mm², and 7.3 mg/cm³, respectively. We found moderate or high correlations in vertebral geometry between our scheme and manual tracking (<i>r</i> &gt; 0.72). In contrast, measurements obtained by using our scheme were slightly smaller than those acquired from manual tracking. However, the outputs of the proposed scheme in most CT cases were regarded to be appropriate on the basis of the subjective assessment of an anatomy expert. Therefore, if the appropriate outputs from the proposed scheme are selected in advance by an anatomy expert, the results can potentially be used for an analysis of vertebral body geometries.

Biomechanical influence of numerical variants of lumbosacral transitional vertebra with Castellvi type I on adjacent discs and facet joints based on 3D finite element analysis.

A 61-year-old man noted flu-like symptoms. Not long afterwards, he felt constipation, nausea, and blackout when standing or sitting. His blood pressure was 110/70 mmHg in the supine position. On sitting blood pressure dropped to 73/34 mmHg. Heart rate increased from 65 to 78 beats per minutes. He did not have fever, edema, or skin rash. The remainder of the general medical examination was normal. A neurological examination revealed normal higher mental, and sensori-motor functions. The blood test revealed leukocytosis 7,320/μl, LD 1,426 IU/l, IL-2R 921 U/ml, and CRP 11.5 mg/dl. A whole body CT scan and cranial MR imaging showed no significant change. Thoracic spine MR imaging revealed multiple T1 low signal small foci in part of the vertebral body suggesting bone metastasis of the tumor. The heart/mediastinum ratio of (123)I-meta-iodobenzylguanidine scintigraphy early imaging was 2.42. The nerve conduction study and electrocardiogram coefficient of variation of R-R intervals showed no abnormalities. Two months after the onset of symptoms, he was found to have glove-and-stocking-form muscle weakness and sensory impairment. The nerve conduction study performed four months after the onset revealed a decreased conduction velocity and conduction block suggesting demyelinated nerve. His neurological manifestations progressed subacutely, despite high-dose intravenous immunoglobulin therapy. Five months after the onset, a histopathological diagnosis of T-cell malignant lymphoma was made on a skin biopsy specimen from the facial rash. To summarise, the present case was a rare example of paraneoplastic autonomic neuropathy as the initial clinical feature in association with T-cell malignant lymphoma.

Anatomically-based skeletal coordinate systems for use with impact biomechanics data intended for anthropomorphic test device development

The objective was to retrospectively evaluate the contribution of fluorodeoxyglucose [18F] positron emission tomography/computed tomography (18FDG-PET/CT) to the re-staging of adrenocortical carcinoma (ACC). A total of 16 patients (10 males and 6 females), who underwent adrenalectomy due to adrenocortical carcinoma and 18FDG-PET/CT scan to re-stage the tumor between July 2007 and April 2013, were included in the present study. The mean age was 53.37 ± 13.91 years (min: 30, max: 74) The patients were required to fast for six hours prior to scanning, and whole-body PET scanning from the skull base to the upper thighs was performed approximately 1 h after the intravenous injection of 555 MBq of F-18 FDG. Whole body CT scanning was performed in the cranio-caudal direction. FDG-PET images were reconstructed using CT data for attenuation correction. Suspicious recurrent or metastatic lesions were confirmed by histopathology or clinical follow-up. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 18FDG-PET/CT were 100%, 83.3%, 90.9%, 83.3%, and 93.7%, respectively. 18FDG-PET/CT detects local recurrence and/or distant metastases with high accuracy in the re-staging of operated adrenocortical carcinoma. It is considered that the procedure could play an important role in treatment decision after the operation and post-operative follow-up and could influence the entire decision-making process.