Early Contrast-enhanced Computed Tomography Research Articles

Is early CT in cases of elevated postoperative CRP the best option for the diagnosis of colorectal anastomotic leakage?

After colorectal surgery (CRS), the early detection and treatment of anastomotic leakage (AL) is critical. We aimed to evaluate the efficacy of early contrast-enhanced computed tomography (CT) (postoperative day [POD] 2-3) after elective colorectal surgery for the diagnosis of AL for patients with elevated CRP levels at POD 2-3. From 2017 to 2022, all patients who underwent elective CRS with an anastomosis and CRP > 150mg/ml on POD 2-3 underwent enhanced CT during the 24h following the CRP evaluation and were included in this retrospective, single-center study. The primary endpoint was the diagnostic value of the early CT scan for the detection of AL. The secondary endpoints were the diagnostic value of the early CT scan for the detection of grade C AL according to the type of resection and anastomosis and the quality of the opacification. A total of 661 patients underwent elective CRS with anastomosis with an overall AL rate of 7.4%. Among the 661 patients, 141 were finally included in the study. The accuracy of early CT for the diagnosis of AL was 83.7%. For grade C AL, the accuracy was 81.6%. Among patients who had an ileocolic anastomosis, the accuracy was 88.2%, among those who had colorectal or ileorectal anastomosis, the accuracy was 83.0%, and among those who had a coloanal, the accuracy was 66.7%. In cases of good opacification by CT, the accuracy was 84.0%. Early CT does not show perfect accuracy for an early diagnosis of AL.

Adrenal metastases: early biphasic contrast-enhanced CT findings with emphasis on differentiation from lipid-poor adrenal adenomas

To evaluate the accuracy of unenhanced attenuation and early biphasic contrast-enhanced computed tomography (CT) in differentiating adrenal metastases (AMs) from lipid-poor adrenal adenomas (AAs). This retrospective study included 37 patients with 50 AMs and 86 patients with 89 lipid-poor AAs. Quantitative data including the longest diameter (LD), the shortest diameter (SD), LD/SD ratio, CT attenuation values (CTu, CTa, CTv), degree of enhancement (DEAP, DEPP, DEpeak, APW, RPW), and peak enhanced/unenhanced (PE/U) CT attenuation ratio were obtained. Qualitative data including enhancement pattern, location, shape, the presence of calcification or haemorrhage, and intra-lesion necrosis were analysed. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were also calculated. The PE/U ratio (≤1.25), CTu (≥32.2 HU), DEpeak (≤43.15 HU), DEPP (≤37.65 HU), presence of intralesional necrosis, location (bilateral adrenal glands), and irregular shape were significant variables for differentiating AMs from lipid-poor AAs (p<0.05). Among them, PE/U ratio (≤1.25) was of greater value in differentiating the two adrenal diseases, with sensitivity, specificity, area under the receiver operating curve (ROC) curve (AUC) of 92%, 84%, 0.933, respectively. When at least any three of above criteria were combined, the sensitivity, specificity, PPV, and NPV for diagnosing AMs were 88%, 93%, 88%, and 88%, respectively. These seven CT criteria are conducive to differentiate AMs from lipid-poor AAs. Early biphasic contrast-enhanced CT is a high-efficient and practical imaging tool in differentiating them.

Hurdles in radiation planning for glioblastoma: Can delayed-contrast enhanced computed tomography be a potential solution?

Conformal radiation is the standard of care in treatment of glioblastoma. Although co-registration of magnetic resonance imaging (MRI) with early contrast enhanced computed tomography (CECT) is recommended for target delineation by consensus guidelines, ground realities in developing countries often result in availability of less-than-ideal MR sequences for treatment planning. Purpose of this study is to analyze the impact of incorporation of delayed-CECT sequences for radiation planning in glioblastomas, as an adjunct or alternative to MRI. Case records of all patients of glioblastoma treated at our center between 2011 and 2014 were retrospectively evaluated. Gross treatment volumes were delineated on T1 contrast MRI (m-GTV), early CECT (e-GTV) and delayed CECT (d-GTV); volumetric comparisons were made using repeated measures analysis of variance and pair-wise analysis. Although 96% of registered patients underwent postoperative MRI, only 38% of them had desirable sequences suitable for co-registration. Median duration between acquisition of postoperative MRI and surgery was 45 days (range, 33-60), whereas that between MRI and treatment-planning CT was 5 days (range, 1-10). Statistically significant differences (P<0.0001) were obtained between mean volumes of e-GTV (41.20cc), d-GTV (58.09cc) and m-GTV (60.52cc). Although the mean GTV increased by 46% between early CECT and MRI, the difference was only 4% between delayed CECT and MRI. Delayed CECT is superior to early CECT for co-registration with MRI for target delineation, especially when available MR sequences are less-than-ideal for treatment planning, and can be considered as the most appropriate adjunct as well as an alternative to MRI, compared to early CECT.

Effects of early contrast-enhanced computed tomography onclinical course and complications in patients with acute pancreatitis.

To investigate the effect of an early contrast-enhanced computed tomography (CECT) on clinical course and complications of acute pancreatitis (AP). 58 patients with AP who had at least one CECT examination were analyzed retrospectively. Laboratory as well as clinical data, and results from the assessment of disease severity (CT severity index (CTSI) and its modified (MCTSI) version) were analyzed. The primary endpoint was the development of severe complications, defined as death, respiratory failure, acute renal failure, and the need for invasive interventions. Patients were divided into two groups: an early group (CECT within the first 48 h after the onset of symptoms, n = 32) and a late group (CECT > 48 h after the onset of symptoms, n = 26). Multivariate regression analysis was performed to identify risk factors for severe complications. There were no statistically significant differences between both groups concerning baseline characteristics, CTSI, and MCTSI. Complications occurred more often in the early CECT group (p = 0.008). Multivariate logistic regression analysis identified an early CECT and a severe MCTSI as independent risk factors for the occurrence of severe complications (p = 0.02 and p = 0.002, respectively). CECT performed within the first 48 h after the onset of symptoms is associated with an unfavorable outcome in AP.

Clinical outcomes and prognostic significance of early vs. late computed tomography in acute pancreatitis.

Background: Guidelines recommend that contrast-enhanced computed tomography (CT) should be carried out 72 hours after onset of an attack of acute pancreatitis (AP). However, the exact time beyond 72 hours at which CT will produce the best diagnostic yield for local complications, or whether doing a CT early in acute pancreatitis has any adverse effect on the course of disease, is not clear.Methods: The medical records of 214 consecutive patients with AP were analysed retrospectively and these patients were divided into two groups: the early CT group (CT done at 4–5 days after the onset of pain) and the late CT group (CT done in days 6–14 following onset of pain). The two groups were compared for differences in clinical outcomes and prognostic information obtained from CT, such as detection of pancreatic necrosis and local complications, and CT severity index.Results: Of 214 patients [143 (66.8%) males; mean age 39.87 ± 13.52 years], 21 patients were excluded as they did not undergo CT or CT was done more than 14 days after onset of an attack of AP. The early CT group included 114 patients, whilst the late CT group had 79. The mean CT severity index was higher in the late CT group (6.65 ± 2.27 vs. 5.52 ± 2.7; P = 0.005). The incidence of persistent organ failure in the early group was no different from that of the late group (38.6% vs. 49.4%; P = 0.143). Local complications were detected more often in the late CT group (84.8% vs. 68.4%; P = 0.011). There was no difference between the two groups in the need for percutaneous drainage, surgery, or mortality (all P > 0.05).Conclusions: Although performing early CT does not adversely affect the outcome in AP, CT carried out more than 5 days after the onset of symptoms may detect more local complications.

Predictive Value of Pattern Classification 24 Hours after Radiofrequency Ablation of Liver Metastases on CT and Positron Emission Tomography/CT

PurposeTo assess a classification scheme for predicting local tumor progression (LTP) after radiofrequency (RF) ablation of liver metastases, using predefined patterns on contrast-enhanced computed tomography (CT) and positron emission tomography (PET) combined with CT (PET/CT) acquired 24 hours after RF ablation. Materials and MethodsThere were 45 metastases in 20 patients treated. After 24 hours, imaging of the ablation zones was performed with contrast-enhanced PET/CT. Three independent radiologists prospectively assessed contrast-enhanced CT and combined PET/CT images to identify three patterns: pattern I, no tissue enhancement or fluorodeoxyglucose uptake between the ablation zone and the liver parenchyma; pattern II, a rimlike pattern; and pattern III, a peripheral nodule. PET/CT images obtained after 8–10 weeks were evaluated for LTP. The patterns were analyzed for their sensitivity, specificity, positive predictive value, and negative predictive value for predicting LTP. ResultsPattern I was most frequently observed (81% for contrast-enhanced CT and 61% for PET/CT) as well as for ablation zones that showed LTP (52% and 37%, respectively). Conversely, pattern II was observed for tumors that were completely ablated (6% and 29%, respectively). Patterns II and III together had the highest sensitivity for predicting LTP (48% and 63%, respectively); pattern III had the highest specificity (94% and 95%, respectively). For nodular patterns, test characteristics were better for PET/CT compared with contrast-enhanced CT, but the difference was not significant. Nodular patterns > 1 cm achieved high positive predictive value (both 100%). ConclusionsInflammation and hyperemia can hinder interpretation on imaging 24 hours after RF ablation, especially on PET/CT. Nodular patterns around the ablation zone on early contrast-enhanced CT and PET/CT have a high predictive value for LTP and should be taken into account for disease management.

Analysis of the power of common diagnostic tools in the management of acute pancreatitis.

Acute pancreatitis (AP) is a serious medical condition usually associated with severe upper abdominal pain. The purpose of our study is to assess the therapeutic consequences of contrast-enhanced computed tomography (CE-CT) and the predictive value of CRP for severe pancreatitis. We included patients with a threefold increase of plasma lipase who had received a CE-CT or had a CRP of =150 mg/dl. A total of 74 out of 283 patients got a contrast-enhanced CT scan; in 11 cases the CT was followed by endoscopic or surgical interventions as therapeutic consequences compared with 19 out of 50 control cases. 69 out of 283 patients (24,3%) had CRP >150 mg/dl within 48 hours after admission. 32 of them had SAP. The CRP cutoff of 150 mg/L had a sensitivity of 80% and a specificity of 65%. The positive predictive value for SAP in patients beyond the cutoff is 46.4%. The negative predictive value for SAP in patients below the cutoff was 89.5%. Our results support the opinion that an early CE-CT is usually not indicated. CRP helps to assess the course of AP; levels below 150 mg/dl between the first 48 h indicate a mild course in most of the cases.

Adenoma Characterization: Adrenal Protocol with Dual-Energy CT

To determine the diagnostic performance of dual-energy computed tomography (CT) by using virtual unenhanced CT to characterize adrenal masses. This study is retrospective, HIPAA-compliant, and approved by the institutional review board. Between December 2009 and June 2010, 49 patients with 49 adrenal masses underwent 120-kVp unenhanced CT and 80-kVp and 140-kVp early and delayed contrast agent-enhanced dual-energy CT. Early virtual unenhanced (EVU) and delayed virtual unenhanced (DVU) CT images were composed of data sets of early and delayed contrast-enhanced CT, respectively. Adenomas were divided into lipid-rich adenoma and lipid-poor adenoma on the basis of lesion attenuation values measured according to unenhanced CT and percentage loss of enhancement. Absolute percentage loss of enhancement was calculated with the following equation: (CT(EE) - CT(DE)) × 100/(CT(EE) - CT(UE)), where CT(UE), CT(EE), and CT(DE) are adrenal mass attenuation values at unenhanced CT, early contrast-enhanced CT, and delayed contrast-enhanced CT, respectively. The sensitivity of adrenal protocol adenoma with delayed contrast-enhanced CT was obtained with a reference standard of unenhanced CT, pathologic examination, or size stability on follow-up examination findings. Lesion attenuation values measured on unenhanced CT, EVU CT, and DVU CT images were compared by using repeated measures analysis of variance with post hoc test. Of 49 masses, 33 were adenomas and 16 were nonadenomas. Adenoma group was 18 lipid-rich adenomas and 15 lipid-poor adenomas. Mean attenuation values of the lipid-rich adenomas on EVU CT images (11.7 HU ± 9.5) were significantly greater than those on unenhanced CT images (0.7 HU ± 7.2) (P = .001) and DVU CT images (6.6 HU ± 8.4) (P = .01). The sensitivities of EVU CT and DVU CT for lipid-rich adenoma were 39% (seven of 18) and 61% (11 of 18), respectively. The sensitivity for adenoma with percentage loss of enhancement values calculated from virtual unenhanced CT and early and delayed contrast-enhanced CT was 100% (33 of 33). Although adrenal protocol with dual-energy CT by using virtual unenhanced CT and washout rate can help diagnose all lipid-poor adenomas, it may miss lipid-rich adenomas that can be diagnosed on unenhanced CT images.

Early localization of necrosis by contrast-enhanced computed tomography can predict outcome in severe acute pancreatitis.

A total of 161 primary contrast-enhanced computed tomography (CT) scans of patients with acute necrotizing pancreatitis taken between 1982 and 1994 were analysed retrospectively. The aim was to assess the prognostic significance of the extent and anatomical site of pancreatic tissue necrosis in the first contrast-enhanced CT scan. The scans were obtained a mean of 2.9 days after the onset of symptoms. The pancreatic head was affected in 107 patients, the body in 119 and the tail in 138. Pancreatic tissue necrosis, when divided into four groups according to anatomical site, correlated with overall clinical outcome. The anatomical site of necrosis was clearly better than its crude extent in predicting the risk of complications. For patients with necrosis in the head of the pancreas, the outcome was as severe as when the entire pancreas was affected. In contrast, for patients with necrosis only in the distal part of the pancreas, the outcome was favourable with few complications. The exact site of pancreatic tissue necrosis should be known when early contrast-enhanced CT is used in prognostic scoring.

Intravenous contrast medium accentuates the severity of acute necrotizing pancreatitis in the rat

Contrast-enhanced computed tomography (CECT) is used to show areas of decreased pancreatic perfusion in severe acute pancreatitis (AP). To evaluate possible adverse effects of the contrast medium (CM) on the course of AP, the impact of intravenous CM in AP of graded severity in the rat was studied. Pancreatitis of three levels of severity was induced in Sprague-Dawley rats with intravenous cerulein hyperstimulation plus time- and pressure-controlled intraductal infusion of saline or glycodeoxycholic acid. At 7 hours, control and pancreatitis animals received intravenous ionic CM, nonionic CM, or saline. The principal outcome measures were 24-hour survival, trypsinogen activation peptides (TAP) in ascites, and histological acinar necrosis score. There was no measurable effect of CM on the index features in control animals or animals with mild or moderate AP. In severe AP, CM caused a significant increase in mortality, ascites TAP, and necrosis score. Intravenous CM increases pancreatic injury when administered early in the course of severe experimental AP. Because CM may convert borderline ischemia to irreversible necrosis, CECT performed early in pancreatitis to show poor perfusion and predict areas of necrosis may depict a self-fulfilling prophecy. Early CECT should be reconsidered and perhaps avoided.

Early diagnosis and classification in acute pancreatitis. A comparison of clinical outcome with findings at computed tomography and Ranson's prognostic signs.

The clinical outcome in 52 consecutive episodes of suspected acute pancreatitis was compared with Ranson's prognostic signs and findings on noncontrast and contrast-enhanced computed tomography (CT) scans performed within 24 h of patient admission. The predictive value of CT scan for diagnosis was 95% for positive results and 53% for negative results. In providing an accurate prognosis of a single attack, scoring of extrapancreatic signs was as good as that of Ranson's prognostic signs. CT with contrast medium revealed pancreatic ischaemia in 3 cases of 4 with clinically severe disease. The risk of developing severe pancreatitis was 23% in first attacks and 6% in relapses. Early CT scan is recommended in most patients with suspected pancreatitis to confirm diagnosis and to predict the severity of an attack.