CT Attenuation Values Research Articles

Diagnostic accuracy of plain computed tomography in detecting acute cerebral venous sinus thrombosis keeping magnetic resonance venography as gold standard.

To determine the diagnostic accuracy of plain computed tomography using the ratio between hounsfield unit and haematocrit of cerebral venous sinuses in cases of acute cerebral venous sinus thrombosis taking magnetic resonance venography as the gold standard. The cross-sectional validation study was conducted at the Department of Diagnostic Radiology, Combined Military Hospital, Rawalpindi, Pakistan, from March 9 to September 8, 2021, and comprised patients regardless of age and gender presenting with acute neurological and visual signs and symptoms of cerebral venous sinus thrombosis for <5 days. The patients were brain-imaged on 128-slice computed tomography scanner, and the image was assessed and the attenuation values in terms of Hounsfield unit of dural venous sinuses were calculated by taking appropriate region of interest. Haemoglobin and haematocrit values were noted from blood reports, and then the ratio between Hounsfield unit and haematocrit ratio was calculated. Magnetic resonance venography of the patients were performed and the patients were assessed for dural venous thrombosis. Data was analysed using SPSS 23. Of the 201 patients, 98(48.8%) were males and 103(51.2%) were female. The overall mean age was 35.32±19.707 years (range: 1 month-70 years). According to the Hounsfield unit-haematocrit ratio, acute cerebral venous sinus thrombosis was detected in 173(86.01%) patients, while magnetic resonance venography detected 178(88.6%). The Hounsfield unit-haematocrit ratio had sensitivity 91.01%, specificity 52.17% and diagnostic accuracy 86.57%. Computed tomography attenuation value and Hounsfield unit-haematocrit ratio on unenhanced computed tomography could be used as a reliable method to detect acute cerebral venous sinus thrombosis in emergency settings.

Quantitative parameters in novel spectral computed tomography: Assessment of Ki-67 expression in patients with gastric adenocarcinoma.

The level of Ki-67 expression has served as a prognostic factor in gastric cancer. The quantitative parameters based on the novel dual-layer spectral detector computed tomography (DLSDCT) in discriminating the Ki-67 expression status are unclear. To investigate the diagnostic ability of DLSDCT-derived parameters for Ki-67 expression status in gastric carcinoma (GC). Dual-phase enhanced abdominal DLSDCT was performed preoperatively in 108 patients with gastric adenocarcinoma. Primary tumor monoenergetic CT attenuation value at 40-100 kilo electron volt (kev), the slope of the spectral curve (λHU), iodine concentration (IC), normalized IC (nIC), effective atomic number (Zeff) and normalized Zeff (nZeff) in the arterial phase (AP) and venous phase (VP) were retrospectively compared between patients with low and high Ki-67 expression in gastric adenocarcinoma. Spearman's correlation coefficient was used to analyze the association between the above parameters and Ki-67 expression status. Receiver operating characteristic (ROC) curve analysis was performed to compare the diagnostic efficacy of the statistically significant parameters between two groups. Thirty-seven and 71 patients were classified as having low and high Ki-67 expression, respectively. CT40 kev-VP, CT70 kev-VP, CT100 kev-VP, and Zeff-related parameters were significantly higher, but IC-related parameters were lower in the group with low Ki-67 expression status than the group with high Ki-67 expression status, and other analyzed parameters showed no statistical difference between the two groups. Spearman's correlation analysis showed that CT40 kev-VP, CT70 kev-VP, CT100 kev-VP, Zeff, and nZeff exhibited a negative correlation with Ki-67 status, whereas IC and nIC had positive correlation with Ki-67 status. The ROC analysis demonstrated that the multi-variable model of spectral parameters performed well in identifying the Ki-67 status [area under the curve (AUC) = 0.967; sensitivity 95.77%; specificity 91.89%)]. Nevertheless, the differentiating capabilities of single-variable model were moderate (AUC value 0.630 - 0.835). In addition, the nZeff VP and nICVP (AUC 0.835 and 0.805) showed better performance than CT40 kev-VP, CT70 kev-VP and CT100 kev-VP (AUC 0.630, 0.631 and 0.662) in discriminating the Ki-67 status. Quantitative spectral parameters are feasible to distinguish low and high Ki-67 expression in gastric adenocarcinoma. Zeff and IC may be useful parameters for evaluating the Ki-67 expression.

Computed tomography values of pericardial effusion may predict chylopericardium: a case report

BackgroundIdiopathic chylopericardium is a rare disease characterized by filling of the pericardial cavity with chylous fluid and has no evident cause. Secondary chylopericardium usually results from injury or damage to the thoracic duct. The most common causes of secondary chylopericardium are trauma, thoracic or cardiac surgery, and congenital lymphangiomatosis. Conservative or surgical treatment can be pursued; however, surgical treatment is required if conservative treatment is unsuccessful. Pericardiocentesis plays a crucial role in the definitive diagnosis of chylopericardium. However, although a serious complication, its occurrence is infrequent. Non-invasive methods, such as computed tomography (CT), could be useful in predicting the color or characteristics of pericardial effusion.Case presentationA 37-year-old Japanese woman presented to our hospital with a cough that persisted for 1 week. Echocardiography revealed pericardial effusion, which was diagnosed as acute pericarditis and treated with loxoprofen. However, pericardial effusion increased, and the patient presented to the emergency room with cardiac tamponade 1 month later. Pericardiocentesis was performed, which confirmed that the pericardial effusion was chylopericardium. Lymphatic scintigraphy did not show any connection between the thoracic duct and pericardial cavity, and the patient was diagnosed with idiopathic chylopericardium. The patient underwent continuous drainage for 11 days. After completion of cardiac drainage, the patient was discharged from the hospital without any exacerbation. The CT attenuation value of the pericardial fluid was 11.00 Hounsfield units (HU). Compared with the other causes of pericardial effusions encountered at our hospital, the HU on CT scan of pericardial effusion was low in our study and similar to the values on CT scan of chylous ascites reported in previous studies.ConclusionsAlthough idiopathic chylopericardium is rare, it should be considered an important cause of pericardial effusion. Pericardiocentesis is necessary for definitive diagnosis; however, the CT findings of pericardial effusion may help predict the presence of chylous fluid.

Exploration of 68Ga-labelled prostate-specific membrane antigen-11 PET/CT parameters for identifying PBRM1 status in primary clear cell renal cell carcinoma

To investigate the predictive value of 68Ga-labelled prostate-specific membrane antigen-11 (68Ga-PSMA-11) integrated positron-emission tomography (PET)/computed tomography (CT) in PBRM1-deficient clear cell renal cell carcinoma (ccRCC). A total of 41 patients with ccRCC, were enrolled retrospectively and underwent 68Ga-PSMA-11 PET/CT preoperatively. Radiological parameters, including CT attenuation value and maximum standard uptake value (SUVmax), were derived. Immunohistochemical and multiple immunofluorescences staining were performed to evaluate the PBRM1 status and immune response. The predictive value of imaging factors was analysed using a receiver operator characteristic curve analysis. Univariate and multivariate logistic regression analyses were used to investigate the relationship between clinical and radiological variables and PBRM1 status. A total of 41 patients were included in this study, with 14 patients having PBRM1-deficient status. The tumour diameter on imaging and SUVmax differed significantly in patients with different PBRM1 expression statuses and no difference in CT attenuation was identified. Univariate and multivariate logistic regression analyses showed SUVmax was an obvious predictor for identification of PBRM1-deficient tumours. In addition, PBRM1-deficient tumours tended to be accompanied by greater cytotoxic T-cell infiltration, although most of them were in an exhausted state. 68Ga-PSMA-11 PET/CT could be used to discriminate invasive PBRM1-deficient ccRCC.

Transarterial ethiodised oil marking before CT-guided renal cryoablation: evaluation of tumour visibility in various renal cell carcinoma subtypes

To evaluate ethiodised oil retention of transarterial embolisation using ethiodised oil (ethiodised oil marking) before computed tomography (CT)-guided percutaneous cryoablation (PCA) according to renal cell carcinoma (RCC) subtype. Ethiodised oil marking was performed 1-3 days before PCA in 99 patients with 99 RCCs from 2016 to 2020. Ethiodised oil retention on CT images was evaluated retrospectively and CT attenuation values in the tumour were measured. Regions of interest (ROI) were placed on the tumours to calculate: average (ROI-average), maximal (ROI-max), minimum (ROI-min), and standard deviation (ROI-SD). Qualitative scores comprising a five-point scale (5, excellent; 1, poor) were evaluated for the retention scores (RS) of ethiodised oil in the tumour (ethiodised oil-RS) and the visualisation scores (VS) of the boundary between the tumour and renal parenchyma (boundary-VS). The histological subtypes comprised clear cell (ccRCC; n=85), papillary (pRCC; n=6), and chromophobe/oncocytoma renal cell carcinoma (chrRCC; n=8). The mean ROI-average, ROI-max, and ROI-SD were significantly higher in ccRCCs than in chrRCCs and pRCCs (p<0.05). The mean ethiodised oil-RS was significantly lower in pRCCs than in ccRCCs (p=0.039), and the mean boundary-VS was >4 in all subtypes. Even with poor intratumour ethiodised oil retention (n=6), sufficient boundary-VS was obtained due to "inverted marking." All PCA procedures were completed without additional intravenous contrast material injection at the time of PCA. Regardless of the tumour subtypes, ethiodised oil marking aids in visualising the boundary between the tumour and parenchyma on non-contrast CT in PCA.

Lobar hepatic steatosis: Association with portal flow hemodynamics evaluated by multiphasic dynamic contrast-enhanced CT

PurposeThis study aimed to evaluate the association of portal flow hemodynamics with lobar hepatic steatosis by means of dynamic contrast-enhanced (DCE) CT. MethodsThe study population consisted of 235 patients, 77 with lobar hepatic steatosis (right, n = 67; left, n = 10), 158 with diffuse hepatic steatosis with (n = 76) and without (n = 82) a focal fatty spared area. CT attenuation values (Hounsfield units: HU) of the liver with and without hepatic steatosis were measured in unenhanced and arterial-phase CT. The contrast enhancement (CE) values were calculated as the difference in HU values between unenhanced and arterial-phase CT. ResultsIn 67 patients with lobar steatosis of the right lobe, the median CE values of the areas of right lobar steatosis were significantly lower than those of the non-fatty left lobe (13 [IQR 7–19] vs 23 [13–33] HU, P < 0.01), suggesting dominant SMV flow to the right lobe with lobar hepatic steatosis. Conversely, in 10 patients with lobar steatosis of the left lobe, the median CE values of the areas of left lobar steatosis were lower than those of the non-fatty right lobe (15.5 [11.75–21.5] vs 16 [14.5–22] HU); however, this difference was not statistically significant (P = 0.20). In 76 patients with a focal fatty spared area, there were significant differences in the median CE values between hepatic steatosis areas and focal fatty spared areas in the gallbladder fossa group (P = 0.01) and in the segment IV group (P < 0.01). ConclusionLobar hepatic steatosis may be associated with regional changes of the portal flow hemodynamics (i.e., predominant perfusion from the SMV flow to the lobes with steatosis).

PS-BPR01-5: DOPAMINE-SECRETING PHEOCHROMOCYTOMA: AN OVERLOOKED CAUSE OF INCIDENTALLY DISCOVERED ADRENAL TUMOR AND NORMAL BLOOD PRESSURE

A 64-year-old woman with a history of chronic thyroiditis and no family history of endocrine disease was incidentally determined to have a left retroperitoneal mass on abdominal ultrasonography. A subsequent abdominal computed tomography (CT) scan revealed a 5.6 × 5.1 × 10.6 cm left adrenal tumor (10–50 Hounsfield Units of CT attenuation value), which showed marginal irregularity and an internal cystic structure [Figure 1A]. She was admitted to our hospital for further investigation of a suspected adrenocortical carcinoma. On admission, she was normotensive and had no symptoms of catecholamine excess. The 24-hour urine catecholamine level showed normal norepinephrine (122.9 ug/day), epinephrine (24.3 ug/day), whereas markedly elevated dopamine (148,212.4 ug/day). 123I-MIBG scintigraphy revealed tumor uptake. After alpha-blockade as preoperative management, she successfully underwent laparoscopic left adrenalectomy and was finally diagnosed with an exclusively dopamine-secreting pheochromocytoma. The tumor was histologically comprised of small polygonal cells with high cellularity and was immunohistochemically positive for all three catecholamine synthesizing enzymes: tyrosine hydroxylase (very weak), dopamine beta-hydroxylase (heterogeneous), and phenylethanolamine N-methyltransferase (very weak). Electron microscopy revealed very few catecholamine-containing small vesicles with a few organelles, which reflected immature cells. No biochemical or imaging evidence of recurrence or metastasis was evident 1 year after the surgery. To our knowledge, this is the first case of an exclusively dopamine-secreting pheochromocytoma in which immunostaining of catecholamine synthetic enzymes and electron microscopy of tumor tissues were performed together to identify the mechanism underlying a dopamine-secreting PPGL. The purpose of this report was to identify the mechanism underlying a dopamine-secreting pheochromocytoma from the histopathological findings. We also discuss the reasons for the lack of catecholamine excess symptoms, whether preoperative management of alpha-blockade is needed, and the association between the prognosis and genetic mutation with an extensive literature review. JOURNAL/jhype/04.03/00004872-202301001-00862/figure1/v/2023-10-24T163949Z/r/image-jpeg

Computed tomographic characteristics of normal salivary glands in dogs.

Various salivary gland diseases diagnosed on computed tomography (CT) in dogs have been reported. However, no study described the size and CT attenuation value of normal salivary glands in dogs. This retrospective analytical study aimed to evaluate the size and attenuation value of the mandibular and zygomatic salivary glands on CT in dogs without cervical or head lesions. The maximum cross-sectional area (MCSA) was measured in 96 dogs and attenuation value on non-contrast and postcontrast images were measured in 90 dogs. Dogs were divided into three groups based on body weight: group 1, ≤ 5.0 kg; group 2, 5.1-10.0 kg; and group 3, 10.1-15.0 kg. There were significant differences in MCSA for both glands among the three groups. There was no difference in MCSA between the left and right sides in both salivary glands. The MCSA for both salivary glands positively correlated with body weight (p < 0.001). There was a significant difference in the MCSA of the zygomatic gland between males and females (p = 0.02), but there was no significant difference in the mandibular gland. There was a significant difference in the attenuation value between the mandibular and zygomatic glands in non-contrast studies (p < 0.001), but there was no significant difference in postcontrast studies. This study established the reference for the size and attenuation value of the mandibular and zygomatic glands in dogs and provided background data for future CT evaluation of dogs with salivary gland diseases.

Correlation of four-phase CT findings of rectal neuroendocrine neoplasms with different World Health Organization grades.

To investigate the four-phase computed tomography (CT) features of rectal neuroendocrine neoplasms (R-NENs) as they relate to different World Health Organization pathological grades. A total of 42 patients who underwent pre-operative four-phase CT for evaluation of neoplasms confirmed as different pathological grades of R-NENs by surgery were included. The CT features were retrospectively analyzed by two radiologists in consensus including the tumor location, shape, long diameter, necrosis, boundary, transmural invasion, CT attenuation values of noncontrast and different enhancement phases, intra mesenteric metastasis, lateral lymph node metastasis, and distant metastasis. The differences among R-NENs of different pathological grades were analyzed using T-test, analysis of variance, and non-parametric rank sum test. Among 42 cases (23 males, 19 females, aged 57 ± 10.48years) of R-NENs, neuroendocrine tumors G1, G2, and G3 (NET G1, NET G2, NET G3) and neuroendocrine carcinoma (NEC) were 13, 13, 3 and 13 cases, respectively. There were statistically significant differences in tumor long diameter, shape, necrosis, boundary, transmural invasion, CT values in delayed phase, intra mesenteric metastasis, lateral lymph node metastasis, and liver metastasis of different pathological grades (P < 0.001, P = 0.014, P = 0.004, P < 0.001, P < 0.001, P = 0.038, P = 0.006, P = 0.022, and P = 0.020, respectively). Features on four-phase CT can correlate with WHO pathological grades of R-NENs; this may be helpful for preoperative diagnosis and prognosis evaluation.

Utility of dual energy CT in differentiating clot in acute ischemic stroke.

Red blood cells (RBC)-poor thrombi in acute ischemic stroke (AIS) are associated with longer recanalization time for mechanical thrombectomy than RBC-rich thrombi. The purpose of the study was to differentiate between RBC-rich and RBC-poor thrombi using dual energy computed tomography (DECT). This retrospective study was conducted on patients with acute arterial occlusion of anterior circulation who underwent DECT cerebral angiography, followed by mechanical thrombectomy with the pathological diagnosis of thrombi, dividing into RBC-rich and RBC-poor thrombi. The CT attenuation values and thrombus enhancement were measured in non-contrast scans and CTA phases at different energy levels and compared between RBC-rich and RBC-poor groups. Fourteen acute stroke patients were included in the study. There were 7 patients in RBC-rich group and 7 patients in RBC-poor group. The CT attenuation values of RBC-rich thrombi were significantly higher than those of RBC-poor thrombi at energy levels of 40, 50, 60, 70, and 80KeV, with the most significant difference at 80KeV (p = 0.032). A cutoff value of 44.1 Hounsfield units (HU) on 80keV monoenergetic reconstructions was used to distinguish between RBC-rich and RBC-poor thrombi. It achieved an area under the curve (AUC) of 0.878, sensitivity of 85.7%, specificity of 100%, and accuracy of 92.9%. The degree of enhancement was higher in RBC-poor thrombi than in RBC-rich thrombi, without statistically significant difference. DECT could help differentiate between RBC-rich and RBC-poor thrombi by using CT attenuation values in non-contrast phase at lower energy levels (40-80KeV).

Use of specific contrast-enhanced CT regions of interest to differentiate renal oncocytomas from small clear cell and chromophobe renal cell carcinomas.

PURPOSE We aimed to examine the usefulness of utilizing a specific contrast-enhanced computed tomog raphy (CT) region of interest (ROI) to differentiate renal oncocytoma (RO) from small clear cell renal cell carcinoma (ccRCC) and chromophobe renal cell carcinoma (chRCC). METHODS A retrospective analysis of pre-contrast phase (PCP), corticomedullary phase (CMP), and nephro graphic phase (NP) contrast-enhanced CT images of the histopathologically confirmed initial cohort (27 ROs, 74 ccRCCs, and 36 chRCCs) was conducted. Small, medium, large, and whole ROIs (S-ROI, M-ROI, L-ROI, and W-ROI, respectively) were utilized for CT attenuation value of tumor (AVT), lesion-to-cortex attenuation (L/C), and heterogeneous degree of tumor (HDT) calcula tions. Differences in these parameters were then compared between RO and ccRCC/chRCC, with receiver operating characteristic (ROC) curves being utilized to gauge the diagnostic utility of the statistically significant parameters. Logistic regression analyses were employed to identify key factors capable of differentiating RO and ccRCC/chRCC, with predictive models further being established. A validation cohort (6 ROs, 30 ccRCCs, and 12 chRCCs) was then employed to vali date the performance of the predictive models. RESULTS Of the parameters evaluated using different ROIs, L/C-CMP (S-ROI) (0.88 ± 0.15 vs. 1.13 ± 0.25, P < .001) and HDT-CMP (W-ROI) (23.02 (12.00-51.21) vs. 37.81 (16.09-89.45), P < .001) were best suited to differentiating RO and ccRCC, yielding respective area under the curve (AUC) values of 0.803 and 0.834. AVT-NP (S-ROI) (122.85 ± 18.87 vs. 86.50 ± 18.65, P < .001) and AVT-NP (M-ROI) (119 (86-167) vs. 81.5 (53-142), P < .001) were better able to differentiate RO and chRCC, yielding respective AUC values of 0.918 and 0.906. Logistic regression analyses revealed that L/C-CMP (S-ROI) and HDT-PCP, as well as AVT-NP (S-ROI) and HDT-CMP, were the primary factors capable of differentiating RO from ccRCC and chRCC, respectively. The predictive model developed to dif ferentiate between RO and ccRCC exhibited a sensitivity of 66.67% and 55.14% in the initial and validation cohorts, respectively, with corresponding specificity of 94.59% and 93.55%, accuracy of 87.13% and 86.84%, and AUC of 0.908 and 0.876. The predictive model developed to differ entiate between RO and chRCC exhibited a sensitivity of 85.19% and 100.00% in the initial and validation cohorts, respectively, with corresponding specificity of 94.59% and 92.86%, accuracy of 87.30% and 95.24%, and AUC of 0.944 and 0.959. CONCLUSION These data demonstrate that a combination of quantitative parameters measured with particu lar ROIs can enable the efficient and reliable differentiation of RO from ccRCC and chRCC for use in routine patient differential diagnosis.

Cervicocerebral Computed Tomography Angiography for Older Patients Based on Time to Peak and Number of Time Points to Peak in the Test Bolus Technique.

This study sought to optimize image quality and reduce the contrast dose by adjusting contrast agent and normal saline doses used in cervicocerebral computed tomography angiography (CTA) of older patients. Older patients who underwent cervicocerebral CTA were divided into group A (n = 110) and group B (n = 124). In the angiography scan, patients in group A were injected with 1.0 mL/kg contrast agent, followed by 40 mL saline chaser. In group B, contrast agent and normal saline doses were adjusted based on time to peak and number of time points to peak in the test bolus technique. The CT attenuation values, noise, signal-to-noise ratio, and contrast-to-noise ratio of target arteries and the right transverse sinus were objectively compared. Compared with group A, the contrast retention and artifacts in the right subclavian vein, right brachiocephalic veins, and superior vena cava were significantly decreased in group B. Furthermore, in group B, the noise at the bifurcation of the right common carotid artery increased by 1.7%, and the signal-to-noise ratio of the left middle cerebral artery M1 segment decreased by 6.6%. The contrast dose in group B decreased significantly (18.2%) as compared with group A. Based on time to peak and number of time points to peak with the test bolus, adjusting contrast and normal saline doses in cervicocerebral CTA for older people reduces contrast retention and artifacts in the veins of the injection side. Further, it also decreases the contrast dose needed to obtain image quality that satisfies diagnostic requirements.

Enhancement of Anemia Detection by Correlating Computed Tomography Findings of Abdominal Aorta and Inferior Vena Cava With Laboratory Investigations.

Anemia affects approximately a quarter of the global population, and improved detection may reduce the associated morbidity and mortality. This study investigated correlations between the results of laboratory hematological determinations of hemoglobin levels and attenuation values measured in the lumina of the abdominal aorta and inferior vena cava (IVC) via unenhanced computed tomography (CT) with the aim of expanding diagnostic options for anemia. The data of 423 patients who underwent abdominal unenhanced CT examinations and laboratory examinations at a tertiary hospital were retrospectively evaluated. CT data were collected using a standard abdominal protocol without contrast. The 151 patients who met the inclusion criteria were categorized by hemoglobin values as follows: <8 (severe anemia), 8-10.9 (moderate anemia), 10.9-12 (mild anemia in females), 10.9-13 (mild anemia in males), and >13 g/dL (non-anemic). The mean CT attenuation values in the aorta and IVC were 37.7 and 36.1 Hounsfield units (HU), respectively. A regression analysis performed to evaluate the correlation and predictability of hemoglobin-based aortic and IVC density yielded a coefficient of determination, R2: 0.42 (F ratio: 149.23, p < 0.0001). The highest contribution in the dependent variable (hemoglobin) was reported to IVC density, showing a significant positive correlation between hemoglobin and IVC density. Our study results demonstrate significant correlations between the densities of the aorta, IVC, and hemoglobin value. Accordingly, radiologists and clinicians can use these readily available values to facilitate diagnosis and patient care.

Pneumonic-type invasive mucinous adenocarcinoma and infectious pneumonia: clinical and CT imaging analysis from multiple centers

BackgroundPneumonic-type invasive mucinous adenocarcinoma (IMA) was often misdiagnosed as pneumonia in clinic. However, the treatment of these two diseases is different.MethodsA total of 341 patients with pneumonic-type IMA (n = 134) and infectious pneumonia (n = 207) were retrospectively enrolled from January 2017 to January 2022 at six centers. Detailed clinical and CT imaging characteristics of two groups were analyzed and the characteristics between the two groups were compared by χ2 test and Student’s t test. The multivariate logistic regression analysis was performed to identify independent predictors. Receiver operating characteristic curve analysis was used to determine the diagnostic performance of different variables.ResultsA significant difference was found in age, fever, no symptoms, elevation of white blood cell count and C-reactive protein level, family history of cancer, air bronchogram, interlobular fissure bulging, satellite lesions, and CT attenuation value (all p < 0.05). Age (odds ratio [OR], 1.034; 95% confidence interval [CI] 1.008–1.061, p = 0.010), elevation of C-reactive protein level (OR, 0.439; 95% CI 0.217–0.890, p = 0.022), fever (OR, 0.104; 95% CI 0.048–0.229, p < 0.001), family history of cancer (OR, 5.123; 95% CI 1.981–13.245, p = 0.001), air space (OR, 6.587; 95% CI 3.319–13.073, p < 0.001), and CT attenuation value (OR, 0.840; 95% CI 0.796–0.886, p < 0.001) were the independent predictors of pneumonic-type IMA, with an area under the curve of 0.893 (95% CI 0.856–0.924, p < 0.001).ConclusionDetailed evaluation of clinical and CT imaging characteristics is useful for differentiating pneumonic-type IMA and infectious pneumonia.

Assessment of epicardial adipose tissue on virtual non-contrast images derived from photon-counting detector coronary CTA datasets

ObjectivesTo assess epicardial adipose tissue (EAT) volume and attenuation of different virtual non-contrast (VNC) reconstructions derived from coronary CTA (CCTA) datasets of a photon-counting detector (PCD) CT-system to replace true non-contrast (TNC) series.MethodsConsecutive patients (n = 42) with clinically indicated CCTA and coronary TNC were included. Two VNC series were reconstructed, using a conventional (VNCConv) and a novel calcium-preserving (VNCPC) algorithm. EAT was segmented on TNC, VNCConv, VNCPC, and CCTA (CTA-30) series using thresholds of −190 to −30 HU and an additional segmentation on the CCTA series with an upper threshold of 0 HU (CTA0). EAT volumes and their histograms were assessed for each series. Linear regression was used to correlate EAT volumes and the Euclidian distance for histograms. The paired t-test and the Wilcoxon signed-rank test were used to assess differences for parametric and non-parametric data.ResultsEAT volumes from VNC and CCTA series showed significant differences compared to TNC (all p < .05), but excellent correlation (all R2 > 0.9). Measurements on the novel VNCPC series showed the best correlation (R2 = 0.99) and only minor absolute differences compared to TNC values. Mean volume differences were −12%, −3%, −13%, and +10% for VNCConv, VNCPC, CTA-30, and CTA0 compared to TNC. Distribution of CT values on VNCPC showed less difference to TNC than on VNCConv (mean attenuation difference +7% vs. +2%; Euclidean distance of histograms 0.029 vs. 0.016).ConclusionsVNCPC-reconstructions of PCD-CCTA datasets can be used to reliably assess EAT volume with a high accuracy and only minor differences in CT values compared to TNC. Substitution of TNC would significantly decrease patient’s radiation dose.Key points• Measurement of epicardial adipose tissue (EAT) volume and attenuation are feasible on virtual non-contrast (VNC) series with excellent correlation to true non-contrast series (all R2>0.9).• Differences in VNC algorithms have a significant impact on EAT volume and CT attenuation values.• A novel VNC algorithm (VNCPC) enables reliable assessment of EAT volume and attenuation with superior accuracy compared to measurements on conventional VNC- and CCTA-series.

Association between extramural vascular invasion and iodine quantification using dual-energy computed tomography of rectal cancer: a preliminary study

ObjectiveThis study aimed to investigate whether histopathological confirmed extramural vascular invasion (EMVI) is associated with quantitative parameters derived from dual-energy computed tomography (DECT) of rectal cancer. MethodsThis retrospective study included patients with rectal cancer who underwent rectal cancer surgery and DECT (including arterial-, venous-, and delay-phase scanning) between November 2019 and November 2020. The EMVI of rectal cancer was confirmed via postoperative pathological results. Iodine concentration (IC), IC normalized to the aorta (NIC), and CT attenuation values of the three phases were measured and compared between patients with and without EMVI. Receiver operating characteristic (ROC) curves were generated to determine the diagnostic performance of these DECT quantitative parameters. ResultsHerein, 36 patients (22 men and 14 women) with a mean age of 62 [range, 43–77] years) with (n = 13) and without (n = 23) EMVI were included. Patients with EMVI exhibited significantly higher IC in the venous and delay phases (venous-phase: 2.92 ± 0.6 vs 2.34 ± 0.48; delay-phase: 2.46 ± 0.47 vs 1.88 ± 0.35) and NIC in all the three phases (arterial-phase: 0.31 ± 0.12 vs 0.24 ± 0.06; venous-phase: 0.58 ± 0.11 vs 0.41 ± 0.07; delay-phase: 0.68 ± 0.10 vs 0.46 ± 0.08) than patients without EMVI. Among them, the highest area under the ROC curve (AUC) was obtained in the delay-phase NIC (AUC = 0.983). IC in the arterial-phase and CT attenuation in all the three phases did not significantly differ between patients with and without EMVI (p = 0.205–0.869). ConclusionIodine quantification using dual-energy CT, especially the NIC of the tumor, differs between the EMVI-positive and EMVI-negative groups and seems to help predict the EMVI of rectal cancer in this preliminary study; however, a larger sample size study is warranted in the future.

Evaluation of Radiation Dose in Computed Tomography Angiography before Transcatheter Aortic Valve Implantation

Objective: To investigate the effective radiation dose and image quality of computed tomography angiography (CTA) before transcatheter aortic valve implantation (TAVI). Material and Methods: This study involved 65 participants, diagnosed with aortic valve stenosis and examined with CTA before TAVI. The total mAs, kVp, volume CT dose index (CTDIvol), and dose–length product (DLP) in each scanning phase were recorded. The effective dose was calculated by multiplying the DLP by the conversion coefficient (k=0.015 mSv/[mGy.cm]). For quantitative image analysis, circular regions of interest were placed on six levels of the aorta in the axial images. The CT attenuation value, image noise, signal-to-noise ratio, and contrast-to-noise ratio were measured. For qualitative analysis, two radiologists rated the image quality of the aortic root and aortoiliac pathway. Results: The mean CTDIvol and DLP were 23.59±5.19 mGy and 881.01±193.41 mGy.cm., respectively. The mean effective dose was 13.22±2.90 mSv; the whole-aorta CTA phase received the highest dose, followed by the coronary CTA and coronary artery calcium scoring phases (9.62±2.60, 2.44±1.13, and 1.16±0.55 mSv, respectively). Image quality ranged from good to excellent in all segments of the aorta. Conclusion: The mean effective radiation dose of the pre-TAVI CT examination using 256-multidetector CT was 22.91± 5.03 mSv. The image quality in the aorta was good to excellent. The main factors that affected the radiation dose were: body mass index, total mAs, and kVp.

A novel use of CT attenuation value: increased bone marrow density in patients with acute myeloid leukemia.

Acute myeloid leukemia (AML) is the most common type of acute leukemia in adults. Bone marrow computed tomography (CT) attenuation may increase in patients with myeloproliferative disorders; however, the actual threshold CT attenuation value predictive of myeloproliferative has not been reported. To determine whether the unenhanced CT attenuation value of the bone marrow may be useful for predicting AML. We retrospectively analyzed patients with AML (n = 56) who underwent unenhanced CT before treatment, and age- and sex-matched controls without any hematologic disease. For each patient, the CT attenuation value (HU) of the iliac bone was measured and compared between the two groups. Receiver operating characteristic (ROC) curve analysis was used to define the cutoff value for predicting AML on all patients, and only on late elderly patients (aged ≥75 years). Patients with AML showed higher bone marrow CT attenuation value (131.4 ± 58.3 vs. 53.9 ± 67.2 HU; P < 0.001), compared to the controls. The sensitivity and specificity for the diagnosis of AML in all patients were 78.6% and 80.4%, respectively, at a threshold value of 90 HU, whereas they were 83.3% and 91.7%, respectively, at 40 HU in late elderly patients. The iliac bone CT attenuation value was elevated in patients with AML and may be useful for predicting AML.

Changes in CT Attenuation Values of Pericardium Months after Radiotherapy as Surrogates for Later Major Cardiotoxicity

<h3>Purpose/Objective(s)</h3> Radiation-induced pericardial disease (RIPD) can manifest as pericardial swelling, thickening, effusion, fluid or calcification. While mostly asymptomatic or underdetected due to self-limiting nature, RIPD could be a surrogate marker for radiation-induced cardiotoxicity. Pericardial screening is not part of standard of care (SOC) for thoracic cancer patients' radiotherapy (RT). Here, we analyze SOC images in patients treated with thoracic RT for radiographically identifiable pericardial changes. We hypothesize that these changes have potential signatures for predicting late major cardiac events. <h3>Materials/Methods</h3> In this retrospective study, pericardium was manually contoured following standard contouring atlases in 30 locally advanced non-small cell lung cancer patients (15 females, 15 males) treated with chemoradiation. A 4mm inner wall was generated as the region of interest. Using pre-RT and (average 10-month) post-RT CT scans, we investigated whether changes in pericardium Hounsfield unit (HU) could predict major late cardiac events reported in patients' clinical records. Taking the effect of contrast-enhancement in some scans into account, HU value ranges representing effusion/fluid, normal tissue and calcification were considered as [-10,30], [31,132] and [133,500], respectively. Support vector machine analysis was performed using data from 24 patients with ≤12 months follow-up for training, and data from the remaining 6 patients for testing. Other parameters of interest for late cardiotoxicity were pericardial doses (mean and max), patient age at the time of RT, sex, history of cardiovascular diagnoses, smoking status, diabetes and hypertension. The CT scans were also revisited by a radiologist for verification of the existence of effusion, fluid, calcification or implants. <h3>Results</h3> In the training group, 11 patients, and in the testing group, 1 patient had a reported major cardiotoxicity several years post-RT. In the cohort of 30 patients, median changes, from pre-RT to post-RT, in the volumes of low, mid, and high HU regions were 17, 24 and 27cc, respectively. In the training set, the volumes of [31,132] HU region showed significant reduction (Mann-Whitney non-parametric test) from pre-RT to post-RT in CT scans of the patients with late cardiotoxicity (p=0.049) compared to those without. Also, patient age at the time of RT was a significant predictor of late cardiotoxicity (p=0.008), while mean dose to pericardium showed borderline significance (p = 0.09). Due to the confounding effect of both contrast-enhancement and implants on the higher HU value analysis, the accuracy of the classification model was limited in training group to 92% and in the test group to 67% (total 4 errors in patients with pre-existing calcifications). <h3>Conclusion</h3> Our preliminary study suggests that radiation-induced cardiotoxicity may be modelled based on patient demographic, dosimetric parameters, and detectable changes in pericardium sac HU volumes.

Relationship between sarcopenia classification and thigh muscle mass, fat area, muscle CT value and osteoporosis in middle-aged and older Japanese adults.

Sarcopenia is one of the most important health issues in today's ageing society. As an evaluation method, computed tomography (CT) is an effective means of assessing not only the quantity but also the quality of skeletal muscle. We aimed to examine the relationship between sarcopenia severity and muscle/fat area, and osteoporosis. 321 patients (116 men and 205 women, mean age 77.2±7.1years, age range 53-96years) who visited the Integrated Healthy Aging Clinic from 2016 to 2017 were included in this study. Based on the Asia Working Group for Sarcopenia2019 criteria, patients were divided into four groups: normal group, low-functional group (with normal skeletal muscle mass, but reduced muscle strength or physical function), sarcopenia group, and severe sarcopenia group. We measured the skeletal muscle (SM), intermuscular adipose tissue (IMAT), and subcutaneous adipose tissue (SAT) areas and the CT attenuation values (CTV) using cross sections of the mid-thigh CT. We also measured bone mineral density. Then, we compared each result among the four groups. We found a significant decrease in SM area in both men and women with sarcopenia (p<0.001 for both sexes). In women, a decrease in SAT area was observed in the sarcopenia group (p<0.001), and an increase in IMAT was observed in the low functional group (p<0.001). The CTV decreased in men with sarcopenia and severe sarcopenia; similarly, women in the low functional and severe sarcopenia groups had decreased CTV (p<0.001 for both sexes). An association between sarcopenia and osteoporosis in men was detected (p=0.004). By using not only muscle mass but also fat mass and CTV, we were able to better examine the pathogenesis of sarcopenia and differences between men and women in Japanese middle-aged and older adults.