Peripheral Computer Tomography Research Articles

Establishment of a predictive model of CT value in the diagnosis and differential diagnosis of pulmonary cryptococcosis

ObjectiveTo investigate the application value of computed tomography (CT) value (HU) in the diagnosis and differential diagnosis of pulmonary cryptococcosis (PC) and to construct a prediction model. MethodsRetrospective analysis of the clinical data of 73 patients who presented with nodular/mass-type occupations on lung CT and confirmed by histopathology in our hospital from January 2019 to May 2022 were divided into PC group (23 patients) and non-PC group (50 patients) according to the pathological findings, and the CT values of each patient's lung lesions were measured. The differences in age, gender, symptoms, lesion involvement in one/both lungs, lung lobe distribution, number of lesions, maximum lesion diameter (cm), lesion margin condition, and CT value results were compared between the two groups. Independent risk factors for PC were analyzed for indicators with statistically significant differences, clinical prediction models were constructed and column line plots were drawn, C (correction) indices were calculated, subject characteristics (ROC) curves were drawn, calibration curves and clinical decision curve analysis (DCA) were performed to further evaluate the predictive efficacy of the models. ResultsComparative analysis of patient data between the two groups showed statistically significant differences in central, peripheral and global CT values (P < 0.05), and multiple regression analysis indicated that central CT value, peripheral CT value and global CT value could be used as independent risk factors for the diagnosis and differential diagnosis of PC. The area under the ROC curve of the model predicting PC was 0.814 (95 % CI: 0.7011–0.9267), and the corrected C-index (Bootstrap = 1000) was 0.781; the actual curve overlapped well with the calibration curve; the DCA results indicated that the column line graph model has high clinical application value. ConclusionsCT value measurements of lesions can be used as an independent risk factor for PC, and clinical prediction models based on the above factors are predictive for the diagnosis and differential diagnosis of PC.

Effective Spatial Resolution of Photon Counting CT for Imaging of Trabecular Structures is Superior to Conventional Clinical CT and Similar to High Resolution Peripheral CT.

Photon counting computed tomography (PCCT) might offer an effective spatial resolution that is significantly improved compared with conventional state-of-the-art computed tomography (CT) and even provide a microstructural level of detail similar to high-resolution peripheral CT (HR-pQCT). The aim of this study was to evaluate the volumetric effective spatial resolution of clinically approved PCCT as an alternative to HR-pQCT for ex vivo or preclinical high-resolution imaging of bone microstructure. The experiment contained 5 human vertebrae embedded in epoxy resin, which were scanned 3 times each, and on 3 different clinical CT scanners: a PCCT (Naeotom Alpha), a dual-energy CT (Somatom Force [SF]), and a single-energy CT (Somatom Sensation 40 [S40]), all manufactured by Siemens Healthineers (Erlangen, Germany). Scans were performed with a tube voltage of 120 kVp and, to provide maximum scan performance and minimum noise deterioration, with exposures of 1500 mAs (SF), 2400 mAs (S40), and 4500 mAs (PCCT) and low slice increments of 0.1 (PCCT) and 0.3 mm (SF, S40). Images were reconstructed with sharp and very sharp bone kernels, Br68 and Br76 (PCCT), Br64 (SF), and B65s and B75h (S40). Ground truth information was obtained from an XtremeCT scanner (Scanco, Brüttisellen, Switzerland). Voxel-wise comparison was performed after registration, calibration, and resampling of the volumes to isotropic voxel size of 0.164 mm. Three-dimensional point spread- and modulation-transfer functions were calculated with Wiener's deconvolution in the anatomical trabecular structure, allowing optimum estimation of device- and kernel-specific smoothing properties as well as specimen-related diffraction effects on the measurement. At high contrast (modulation transfer function [MTF] of 10%), radial effective resolutions of PCCT were 10.5 lp/cm (minimum resolvable object size 476 μm) for kernel Br68 and 16.9 lp/cm (295 μm) for kernel Br76. At low contrast (MTF 5%), radial effective spatial resolutions were 10.8 lp/cm (464 μm) for kernel Br68 and 30.5 lp/cm (164 μm) for kernel Br76. Axial effective resolutions of PCCT for both kernels were between 27.0 (185 μm) and 29.9 lp/cm (167 μm). Spatial resolutions with kernel Br76 might possibly be still higher but were technically limited by the isotropic voxel size of 164 μm. The effective volumetric resolutions of PCCT with kernel Br76 ranged between 61.9 (MTF 10%) and 222.4 (MTF 5%) elements per cubic mm. Photon counting CT improved the effective volumetric resolution by factor 5.5 (MTF 10%) and 18 (MTF 5%) compared with SF and by a factor of 8.7 (MTF 10%) and 20 (MTF 5%) compared with S40. Photon counting CT allowed obtaining similar structural information as HR-pQCT. The effective spatial resolution of PCCT in trabecular bone imaging was comparable with that of HR-pQCT and more than 5 times higher compared with conventional CT. For ex vivo samples and when patient radiation dose can be neglected, PCCT allows imaging bone microstructure at a preclinical level of detail.

Multiphase vascular lower limb computed tomography: Assessment of patients doses and radiogenic risk

The purposes of this study are to estimate patient's radiation doses and radiogenic risk in vascular lower limb computed tomography (CT). In total, 188 (109 (68%) males and 79 (42%) females) patients undergone vascular CT for the lower limbs at three radiology departments. Three CT scanners, 160, 128, and 64 slices CT, were used in this study. CT-Expo and ImPACT CT dose estimation software were used to extrapolate the effective dose. The overall average and range of volume CT dose index (CTDIvol (mGy) and dose length product (DLP) (mGy.cm) 7.3 (2.3–22.9), and 3000 (279.1–8374.4) the same order. The overall effective dose average value was 18 mSv per procedure. The proposed diagnostic reference level (DRL) values are 9 mGy (CTDIvol) and 2500 mGy cm (DLP) per vascular lower limb CT procedure. The risk of cancer from the peripheral CT angiography procedures ranges from 1 in 1000 to 1 in 3000 procedures. The cancer risk per procedure should be considered during the justification and image acquisition stages.

Comparison of Magnetic Resonance Imaging and Computed Tomography in the Evaluation of the Olfactory Cleft and Ethmoidal Cells.

No study has examined whether magnetic resonance imaging (MRI) alone can be used for evaluating olfactory cleft and ethmoidal sinus in patients with olfactory disorders. Therefore, we analyzed the discrepancies between computed tomography (CT) and MRI in the imaging of the olfactory cleft and ethmoidal sinus. Patients who underwent CT and MRI within 30 days were evaluated. Age, sex, diagnosis, presence of bronchial asthma (BA), peripheral blood eosinophil percentage, and CT and MRI findings were retrospectively reviewed, and the sinuses were assessed on a scale of 0 to 3. Overall, 146 patients with 292 sinuses were enrolled. The ethmoid sinus score and the olfactory cleft score had 77.1% and 72.6% image similarity in CT and MRI. Sex and BA status were not associated with olfactory cleft score discrepancies (sex: P = 0.52, BA: P = 0.41). Magnetic resonance imaging scores tended to be rated higher than the CT scores as age increased, although this difference was not statistically significant (P = 0.09). The higher the peripheral blood eosinophil percentage, the more the magnitude by which the CT score tended to exceed the MRI score; however, this finding was also not statistically significant (P = 0.11). Magnetic resonance imaging scans should be limited to the evaluation of intracranial regions. Scans of olfactory cleft and ethmoid cells are not accurate for the assessment of olfactory dysfunction.

Recent Advances in Imaging for Diagnosis, Monitoring, and Prognosis of Psoriatic Arthritis.

Psoriatic arthritis (PsA) is an inflammatory condition characterized by a strong heterogeneity and multifaceted behavior. PsA manifests in two types—axial and peripheral—which may be present at the same time. Peripheral manifestations can be further divided into the articular (arthritis) and extra-articular (i.e., enthesitis and dactylitis) subgroups. In such a complex disease, imaging is often required to characterize the type of involvement and to evaluate the radiological damage and progression of PsA. In addition, imaging plays a pivotal role in clinical practice; that is, for axial involvement. Conventional radiology has been the main standard of reference for many years. However, in recent years, there has been growing interest in different imaging modalities, such as ultrasonography (US) and magnetic resonance imaging (MRI). All these techniques play a role in the diagnosis and follow-up of patients with PsA and cover all the types of the disease. US and MRI have good sensitivities and specificities for detecting synovitis, and this may be helpful for differential diagnosis with other musculoskeletal diseases and useful in the early or preclinical phases of the disease. However, US is not useful in the diagnosis of axial PsA. In addition, other modalities have been investigated in the field of PsA imaging. Computed tomography (CT), in particular, dual energy-CT and high-resolution peripheral CT (HRpQ-CT) might play an important role in the assessment of bone damage, erosions, and new bone formation. Regarding advanced functional imaging, FDG PET/CT is another interesting technique for exploring disease activity.

SARS-CoV-2 Detection on Bronchoalveolar Lavage: An Italian Multicenter experience

Background: Bronchoscopy with bronchoalveolar lavage (BAL) during the SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) pandemic should be reserved to a limited number of clinical indications. The yield of BAL for the diagnosis of suspected or confirmed pulmonary SARS-CoV-2 infection is still unknown. Objectives: We aimed to evaluate the diagnostic ratio of BAL in detecting SARS-CoV-2 pulmonary infection in patients undergoing bronchoscopy for different indications as well as describe the clinical, radiological, and endoscopic characteristics of patients with SARS-CoV-2 on BAL. Method: We conducted a multicenter retrospective study including all patients who underwent bronchoscopy for the detection of SARS-CoV-2 on BAL. Clinical, computed tomography (CT), endoscopic, and microbiologic data were gathered from March 16th to May 27th, 2020. Results: 131 patients were included. Bronchoscopy was performed for suspected SARS-CoV-2 infection (65.5%), alternative diagnosis (12.9%), suspected superinfections (19.8%), and lung atelectasis (1.5%). SARS-CoV-2 was isolated on BAL 43 times (32.8%) and the highest isolation rate was in patients with suspected SARS-CoV-2 infection (74.4%); 76% of positive patients had a double-negative nasopharyngeal swab. Peripheral, posterior and multilobar CT opacities were more frequent in SARS-CoV-2 patients, and the number of CT findings was higher in positive patients, particularly those with suspected SARS-CoV-2 infection. We recorded a progressive reduction of SARS-CoV-2 isolation during the observation period. Conclusions: In our centers, the rate of detection of SARS-CoV-2 on BAL in patients with suspected infection was 37.2%. The agreement of BAL with nasopharyngeal swabs was high; CT alterations could predict the pretest probability of SARS-CoV-2 infection, but suspicion of viral infection should be always considered.

Optimal control of asthma improved eosinophilic otitis media.

BackgroundEosinophilic otitis media (EOM) is often associated with comorbid asthma. The middle ear cavity is part of the upper airway. Therefore, EOM and asthma can be considered to be a crucial part of the “one airway, one disease” phenomenon. Based on the concept of one airway, one disease in the context of allergic rhinitis and asthma, optimal level of inhalation therapy for better asthma control leads to improvement in allergic rhinitis.ObjectiveWe conducted a pilot study to determine whether appropriate strengthening of inhalation therapy for asthma is effective for EOM.MethodsFifteen patients with EOM and comorbid asthma were enrolled in this study. Eight patients were randomly selected and administered appropriately strengthened inhalation therapy for asthma (strengthened group). The effect of the therapy on EOM was assessed by comparing a questionnaire for ear symptoms, clinical characteristic score, pure tone audiometry, blood tests and temporal bone computed tomography (CT) examination before and after the therapy. Seven other EOM + asthma patients without the above mentioned therapy were included as controls.ResultsIn the strengthened group, the score of ear symptoms, clinical characteristics score, peripheral blood eosinophil count, CT score, and air conduction hearing level improved significantly after strengthening the inhalation therapy, but not in the control group. The lung function tests (forced vital capacity [%predicted], forced expiratory volume in 1 second [FEV1] [L], and FEV1 [%predicted]) significantly increased in the strengthened group after the therapy, but not in the control group.ConclusionIn this study we demonstrated that EOM improved along with improved lung function when appropriately optimal inhalation therapy was implemented in patients with EOM and asthma. Administration of optimizing therapy for asthma might be effective for concomitant EOM.

Quantitative Computed Tomography—Current Status and New Developments

This review focuses on new developments and current controversies in the field of quantitative computed tomography. Recent positions of the International Society for Clinical Densitometry acknowledged the clinical value of quantitative computed tomography of the spine and the hip using clinical whole-body computed tomography (CT) scanners. Opportunistic screening summarizes a number of new approaches describing the dual use of clinical CT scans. For example, CT scans may have been taken for tumor diagnosis but may also be used for the prediction of high or low fracture risks as an additional benefit for the patient. The assessment of the cortical parameters is another topic of current research. In CT images of the spine and the hip, a number of techniques have been developed to determine the thickness, mass, and bone density of the cortex. In higher-spatial resolution peripheral CT images of the radius and tibia obtained from special purpose scanners, 1 focus is the measurement of cortical porosity. Two different approaches, one based on the direct segmentation of the pores and one based on cortical density, will be reviewed.

Effect of Automated Attenuation-based Tube Voltage Selection on Radiation Dose at CT: An Observational Study on a Global Scale.

To evaluate the effect of automated tube voltage selection (ATVS) on radiation dose at computed tomography (CT) worldwide encompassing all body regions and types of CT examinations. No patient information was accessed; therefore, institutional review board approval was not sought. Data from 86 centers across the world were analyzed. All CT interactions were automatically collected and transmitted to the CT vendor during two 6-week periods immediately before and 2 weeks after implementation of ATVS. A total of 164 323 unique CT studies were analyzed. Studies were categorized by body region and type of examination. Tube voltage and volume CT dose index (CTDIvol) were compared between examinations performed with ATVS and those performed before ATVS implementation. Descriptive statistical methods and multilevel linear regression models were used for analysis. Across all types of CT examinations and body regions, CTDIvol was 14.7% lower in examinations performed with ATVS (n = 30 313) than in those performed before ATVS implementation (n = 79 275). Relative reductions in mean CTDIvol were most notable for temporal bone CT (-56.1%), peripheral runoff CT angiography (-48.6%), CT of the paranasal sinus (-39.6%), cerebral or carotid CT angiography (-36.4%), coronary CT angiography (-25.1%), and head CT (-23.9%). An increase in mean CTDIvol was observed for renal stone protocols (26.2%) and thoracic or lumbar spine examinations (6.6%). In the multilevel model with fixed effects ATVS and examination type, and the interaction of these variables and the random effect country, a significant influence on CTDIvol for all fixed efects was revealed (ATVS, P = .0031; examination type, P < .0001; interaction term, P < .0001). ATVS significantly reduces radiation dose across most, but not all, body regions and types of CT examinations.

Dual-energy CT angiography of pelvic and lower extremity arteries: dual-energy bone subtraction versus manual bone subtraction

To analyse the effect of dual-energy bone subtraction (DEBS) on the image quality of peripheral computed tomography (CT) angiograms. Twenty patients underwent dual-energy CT angiography of the pelvic and lower extremity arteries using commercially available equipment. Two different methods of image processing were employed for each CT angiographic dataset: (1) DEBS, and (2) manual bone subtraction (MBS). Effects on vessel visibility and artificial vessel alterations were compared. Bone removal, and the resultant visibility of vessel segments, were significantly better with DEBS than with MBS (p=0.011). The overall frequency of vessel-related alterations was lower in MBS compared with DEBS (p=0.001). Specifically, in the 249 vessel segments with calcified plaques, MBS generated fewer vessel alterations than DEBS (p<0.001). In the 309 vessel segments without calcified plaques, there was no difference in vessel alteration between the two techniques (p=0.22). DEBS facilitates bone removal in peripheral CT angiography, but generates more vessel alterations, particularly in the presence of calcified plaque.

Racial differences in bone density and fracture risk in the United States

AbstractMany studies indicate racial differences in areal bone mineral density (aBMD). African‐Americans tend to have the greatest aBMD, followed by Caucasian, Hispanic and Native Americans. Asian Americans, on average, have the lowest aBMD. Differences in aBMD are attenuated when adjustments are made for bone size, weight and lifestyle factors. While many studies have focused on racial differences in bone density, it is important to consider fracture risk since it is the clinically meaningful outcome and is determined by many factors other than bone density. African‐ and Asian‐Americans have a relatively low risk of fracture compared to other groups, despite drastically different bone density, as measured by dual X‐ray absorptiometry (DXA). Factors that cannot be completely evaluated by DXA, such as bone size, volumetric density, bone microarchitecture and turnover may be important in explaining disparate fracture rates. Newer technologies such as central quantitative computed tomography (CT) and high‐resolution peripheral CT promise to contribute important knowledge in this regard. Despite recent advances, more fracture risk data is needed for non‐Caucasian groups to assist in the development of relevant screening and treatment guidelines.

Optimization of Region of Interest Luminances May Enhance Radiologists’ Light Adaptation

Radiologic image details are best discriminated at luminance levels to which the eye is adapted. Recommendations that ambient light conditions are matched to overall monitor luminance to encourage appropriate adaptation are based on an assumption that clinically significant regions within the image match average monitor luminance. The current work examines this assumption. Three image types were considered: posteroanterior (PA) chest; PA wrist; and computed tomography (CT) head. Luminance at clinically significant regions was measured at hilar region and peripheral lung (chest), distal radius (wrist), and supraventricular white matter (head). Average monitor luminances were calculated from measurements at 16 regions of the display face plate. Three ambient light levels-30, 100 and 400 lux-were employed. Thirty samples of each image type were used. Statistically significant differences were noted between average monitor luminances and clinically important regions of interest of up to a factor of 3.8, 2, and 6.3 for chest, wrist, and CT head images respectively (P < .0001). Values for the hilum of the chest and distal radius were higher than average monitor levels, whereas the reverse was observed for the peripheral lung and CT brain. Increasing ambient light had no impact on results. Clinically important radiologic information for common radiologic examinations is not being presented to observers in a way that facilitates optimized adaptation. This may have a significant impact on the ability of the observer to identify details with low contrast discriminability. The importance of image-processing algorithms focussing on clinically significant abnormalities rather than anatomic regions is highlighted.

Total IgE Levels and Peripheral Eosinophilia

To evaluate the relationship among peripheral eosinophilia, total IgE, and paranasal sinus mucosal disease based on computed tomography (CT) of the sinus. Retrospective review of a large medical information database from a tertiary referral medical center. Tertiary referral medical center specializing in respiratory disorders. Consecutive patients having total IgE and peripheral eosinophil levels and sinus CT imaging available for review. Patients 18 years or older were included; subjective or objective evidence of chronic rhinosinusitis was not used as selection criteria. A total of 303 patients were found to have peripheral eosinophil levels and CT imaging for review; 288 patients had total IgE levels and CT imaging. Linear regression analysis was used to evaluate (1) the correlation between peripheral eosinophil level and CT stage of sinus disease and (2) the correlation between total IgE level and CT stage of sinus disease. The CT scans were graded using the Lund-MacKay scoring system. There was a significant positive correlation between sinus CT stage and peripheral eosinophil levels (r=0.60, P<.05). Eighty-nine percent of the abnormal eosinophil counts (>550 cells/microL) were associated with CT scores higher than 12. Total IgE did not correlate with CT stage of disease (r=0.05, P>.05). The presence of peripheral eosinophilia indicates a high likelihood of mucosal sinus disease based on CT imaging. No correlation was noted between total IgE levels and CT stage of mucosal disease. These data support a link between eosinophilia and the presence of paranasal sinus mucosal inflammation.