Precontrast Series Research Articles

Dual-energy Computed Tomography in Coronary Artery Calcium Scoring

Computed tomographic (CT) coronary artery angiography with calcium scoring is crucial in suspecting coronary artery disease (CAD). The routine protocol for CAD radiological investigation involves a precontrast series for calcium scoring and a postcontrast series for investigating structural changes in coronary arteries. This review intends to investigate the feasibility of virtual noncontrast images to replace the true noncontrast (TNC) images in coronary artery calcium scoring to decrease the radiation dose. The current review included articles found in the PubMed database. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for the further evaluation of the articles for inclusion criteria, 25 articles were finally shortlisted for the final review. It is found that the calcium score of coronary arteries estimated by virtual unenhanced images generated by dual-energy CT (DECT) is comparable with that of TNC images. The virtual unehncanced images has the potential to eliminate the need for the TNC series acquisition, thereby reducing the radiation dose. Especially, photon-counting detector-based DECT has excellent potential in the estimation of calcium scores and the reduction in radiation dose. In addition, contrast dose also can be significantly reduced, which is crucial in patients with renal insufficiency. In conclusion, using DECT for CAD investigations significantly reduces both radiation and contrast doses compared to conventional CT scans. This reduction is particularly crucial for patients who require repeated follow-up scans, as it enhances their safety and minimizes potential risks.

P-01 Case report of adrenal insufficiency due to bilateral adrenal hemorage

Abstract Introduction Arterial or venous thrombosis may be seen in the presence of antiphospholipid antibody (AFA). Rarely, it can cause adrenal hemorrhage. In this case, a 39-year-old case of adrenal insufficiency due to adrenal hemorrhage accompanied by AFA is presented. Clinical Case A 39-year-old male patient with no known disease was admitted to the emergency service with complaints of abdominal pain, general condition disorder, weakness, nausea and vomiting. Hypotension, Na:121meq/L (136-145 meq/L) and K:6.2 meq/L (3.5-5 meq/L), creatinine: 3.56 mg/dl (0.7-1.20), urea: 50.5 mg /dl (6-20), cortisol value measured by suspecting acute adrenal insufficiency was 1.42 µg/dL (5-25 µg/dL), ACTH value was 561 pg/mL (10-46 pg/mL). Abdominal CT for abdominal pain showed a collection area of 58 mm ap diameter on the right and 66 mm ap diameter on the left in both surrenal lobes, and numerous millimeter-sized hypointense areas in the subcapsular area of both kidneys and were evaluated as significant in terms of microinfarcts. Then, areas that were hyperdense in the precontrast series and did not show significant enhancement in the postcontrast series were evaluated for bleeding in adrenal CT (Figure 1).In the tests performed, aPTT 44.5 sec (24-40), C3 1.272 g/dL (0.9-1.8 g/dL), ANA:1/160 homogeneous positive granular, anti-dsDNA:28 IU/mL, lupus anticoagulation positive, in complete urinalysis proteinuria and hyaline cast were detected. The patient was diagnosed with AFAS and systemic lupus erythematosus (SLE), and hydroxychloroquine was started. Warfarin and acetylsalicylic acid were started due to renal vein thrombosis. Stress-dose steroid therapy (80 mg/day methylprednisolone) was started in the patient who was suspected of having adrenal insufficiency due to adrenal hemorrhage. The hemorrhage in our patient was attributed to the hemorrhage caused by the AFA-related infarction. The patient who completed the treatment was discharged with 200 mg hydroxychloroquine, 30 mg hydrocortisone, 0.5 mg fludrocortisone, 5 mg warfarin, 100 mg acetylsalicylic acid, 10 mg amlodipine. Conclusion Although the pathogenetic mechanism of adrenal insufficiency seen in AFA syndrome is not fully known; increased coagulation status in these patients is held responsible. Adrenal insufficiency is thought to be due to hemorrhage after venous thrombosis at the adrenal vein or microvascular level. AFA-related adrenal insufficiency is usually permanent and rarely resolves. Therefore, long-term follow-up of these patients is required. The presence of AFA should be investigated in patients presenting with bilateral adrenal hemorrhage.Figure 1.Sürrenal bt

Added value of delayed post-contrast FLAIR in diagnosis of metastatic brain lesions

BackgroundOne of the drawbacks in contrast-enhanced T1-weighted imaging (CE-T1WI) is the enhancing cortical vessels which can be confused with meningeal enhancement. Previous studies reported that post-contrast FLAIR could be better for diagnosing the superficial brain abnormalities. So the purpose of this study was to evaluate the role of delayed post-contrast FLAIR, in comparison with post-contrast T1, in the detection and evaluation of brain metastases.ResultsThe study was conducted on 40 patients with suspected/known brain metastases scanned in order to detect and evaluate brain metastases. All patients were subjected to the following: full history taking, review of clinical examination reports, and other imaging modalities whenever available, followed by brain MRI examination using 1.5 T closed magnet including pre-contrast series, axial and sagittal T1-weighted spin echo (SE), axial and coronal T2-weighted turbo spin echo (TSE) and axial FLAIR, while post-contrast series included axial, coronal and sagittal T1-weighted spin echo (SE) and lastly DPC-FLAIR sequence 10 min after contrast administration. This study included 18 males and 22 females, ranging in age from 26 to 75 years. Six out of a total of 40 patients had brain metastases of unknown origin, while 34 of them were presented with different types of known primary tumors. The detected lesions were subdivided into five groups according to their detectability by DPC-FLAIR and contrast-enhanced T1WI: Group (I): lesions detected only by DPC-FLAIR: 16 lesions; Group (II): lesions detected only by CE-T1WI: 1 lesion; Group (III): lesions detected by both DPC-FLAIR and CE-T1WI with equal conspicuity by both: 28 lesions; Group (IV): lesions detected by both, showing more obvious enhancement with DPC-FLAIR: 43 lesions; and Group (V): lesions detected by both, showing more obvious enhancement with CE-T1WI: 11 lesions. DPC-FLAIR had a sensitivity of 98.98% and a specificity of 100% for the detection of metastatic brain lesions and for CE-T1WI; sensitivity of 83.83%; and a specificity of 50%.ConclusionsDelayed post-contrast FLAIR is a reliable sequence for the detection of metastatic brain lesions as it can detect more metastatic brain lesions compared to contrast-enhanced T1WI.

Intrapancreatic accessory spleen: Findings on MR imaging and CT

BackgroundAlthough intrapancreatic accessory spleen (IPAS) are infrequently noticed radiologically, they have been reported up to 2, 8% in Autopsies. The aims of this study were to describe the imaging characteristics of IPAS using computed tomography (CT) and/or magnetic resonance imaging (MRI) to prevent an unnecessary surgery. Materials and methodsDuring last 7 years, 5 consecutive patients with incidental intrapancreatic accessory spleen (IPAS) on the tail of pancreas which radiologically mimicked a neuroendocrine pancreatic tumor, surgically treated in our university hospital. Preoperative CT studies (4 of 5 patients) and MRI (2 of 5 patients, one patient had both CT and MR images), operation reports and pathological diagnoses were analyzed retrospectively. For each lesion, images were analyzed based on the characteristic signal intensities on MRI or density of the lesion on CT images and presence of contrast enhancement. Pathologic correlation was available for the lesions. ResultsThe female-to-male ratio was 2:3, with a mean age of 56 years (age range, 42–72 years). Incidental lesion findings were due to imaging studies using magnetic resonance imaging and/or computed tomography. In all the patients there was just one lesion on the tail of pancreas. On all the MR images (2 of 5 patients), a focal pancreatic lesion that was in compared to the rest of pancreas hypointense on T1-weighted sequences were detected, these lesions were hyperintesne on T2-weighted sequences; and enhanced more than the pancreas tissue in contrast enhanced series; however, the lesions were with the same intensity in compared to spleen in all the sequences. The enhancement pattern of the lesion was evaluated as serpiginous on early postgadolinium sequences. On all CT studies (4 of all 5 patients), there were no detectable lesions on pre-contrast series; however, on all arterial and venous series lesions were hyperdens in contrast to the rest of pancreas. The lesions had the same density of spleen in all series. In both MRI and CT images there were No adenopathy in the abdomen. Tumor size was among min. 9 × 12 mm to max. 16 × 18 mm. Pathological findings were intrapancreatic accessory spleen (IPAS) in all the cases. One patient had a pathological finding of Leiomyoma of the stomach too. ConclusionRadiologists and Surgeons should be aware that an incidental finding of a subtle well-marginated, rounded solitary lesion on the tail of pancreas on the CT or MR images which matches the density/or intensity of the spleen on all phases/ or sequences could be an intrapancreatic accessory spleen (IPAS); Therefore, an IPAS has to be excluded in asymptomatic patients with a lesions in the pancreatic tail before unnecessary surgery.

Mimics of Complications in the Postsurgical Aorta at CT.

Various surgical techniques of the aorta result in expected imaging appearances on CT images that resemble complications such as pseudoaneurysm, perigraft abscess, and dissection. Awareness of these techniques, understanding the clinical situation in which they are performed, and familiarity with the typical appearances and locations of these mimics are essential for accurate interpretation. CT imaging techniques such as electrocardiographic gating and inclusion of a precontrast series can help distinguish an expected postsurgical finding from a complication. Information in the medical record, particularly the operative note, can clarify challenging cases with unusual imaging features. This review article provides examples of expected postsurgical findings at CT mimicking complications. © RSNA, 2019.

Liver Functional Evaluation Using Gadoxetic Acid Versus the Gold Standard Hepatobiliary Scintigraphy in Patients with Bile Duct Diseases

Objective. To compare liver function assessments using Gd-EOB-DTPA-enhanced MRI and the gold standard hepatobiliary scintigraphy (HBS) in patients with bile duct diseases.Material and methods. The investigation enrolled 18 patients (male/female = 11/7; age, 29–70 years, Klatskin tumor (n=16), bile duct epithelial dysplasia (n=1), intrahepatic cholangiolithiasis (n=1)) after biliary decompression, who underwent 21 paired MRIs and 99mTc-mebrofenin HBS at a study interval of no more than 3 days. In the same regions of interest with a size of 30–50 pixels located in liver segments II–III, IV, V–VIII, and VI–VII, a MRI signal was measured before MR contrast agent (MRCA) injection into the standard vascular phases and at 10, 20, 30 and 40 minutes, then the signal was expressed as a percentage of intensity compared to the precontrast series. After MR volumetry, the functional volumes of the left and right liver lobes were also defined as the area under the MRCA accumulation curve, which was multiplied by the lobe volume and expressed as a percentage of the similarly calculated function of the entire liver. Similar intensity parameters and functional volumes were estimated for a HBS study.Results. The lobe functional volumes measured by the two methods were highly correlated (R=0.8; p<0.001) and did not show a significant difference at all when comparing with the Mann–Whitney test (p>0.3). The excretion rate of 99mTc-mebrofenin was also highly correlated with MRI findings (R=0.5–0.9; p<0.05). Conclusion. Gd-EOB-DTPA-enhanced MRI revealed a high correlation with the gold standard; however, additional studies are needed to clarify the possibilities and limitations of replacing one method with another one.><0.05).Conclusion. Gd-EOB-DTPA-enhanced MRI revealed a high correlation with the gold standard; however, additional studies are needed to clarify the possibilities and limitations of replacing one method with another one.

CT attenuation values and mineral distribution can be used to differentiate dogs with and without gallbladder mucoceles.

Gallbladder mucoceles are potentially fatal in dogs. Multiphase CT angiography was performed to evaluate the canine gallbladder in three conditions: no sludge, sludge occupying ≥25% of the lumen, and mucoceles. Twenty dogs with normal hepatobiliary bloodwork and no-to-minimal gallbladder sludge, 13 dogs with normal bloodwork and ≥25% sludge in the gallbladder lumen, and 18 dogs with histologically confirmed gallbladder mucoceles were enrolled in a prospective, observational diagnostic accuracy study. Three regions of interest (ROI) were stratified in the dorsal-ventral orientation and a single ROI was measured within the hepatic parenchyma. Mean attenuation and presence of mineral were recorded. Average Hounsfield units (HU) were recorded for precontrast, arterial, portovenous, and late venous phases. The overall median HU value for mucoceles was significantly higher than gallbladders without sludge and with sludge; precontrast median overall attenuation was 49.3, 35.8, and 39.7 HU, respectively (P<.000004). Mineral was seen in four (20%) dogs with no sludge, seven (56%) dogs with sludge, and nine (50%) dogs with mucoceles. Mineral in the dogs with mucoceles was located within the central aspect of the gallbladder lumen in 67% of mucoceles; this mineral distribution was not seen in any dog without a mucocele. Computed tomography can differentiate a subset of gallbladder mucoceles from dogs with and without gallbladder sludge, especially in the precontrast series. An HU value of 48.6 is 52% sensitive and 96% specific for a gallbladder mucocele. A hyperattenuating gallbladder on precontrast CT images and centrally distributed mineral can be a gallbladder mucocele.

Multi-detector computed tomography (MDCT) findings of chemotherapy induced hepatic changes

PurposeTo evaluate the role of multi-detector computed tomography (MDCT) in detection and characterization of chemotherapy induced hepatic changes. Materials and methodsThis retrospective study included 400 patients with confirmed 14 malignancies and treated by standard chemotherapy regimens. The most common malignancy was non-Hodgkin lymphoma and mostly chemotherapy regimen was Cyclophosphamide, Hydroxydaunomycin, Oncovin and Prednisolone (CHOP). All patients underwent CT scan using 64 MDCT scanner (Brilliance 64, Philips) before chemotherapy and follow-up after 6months from last session of chemotherapy. Precontrast series and post-contrast triphasic study were done for all patients. All the patients underwent radiological evaluation for hepatic changes after chemotherapy treatment. All CT scans were evaluated for fatty liver, capsular retraction, venoocclusive disease and biliary sclerosis. Four patients with capsular retraction underwent liver biopsy. ResultsForty patients (32 females and 8 males) had hepatic changes due to effect of chemotherapy. The most common CT finding was fatty liver. Hepatic fatty changes were detected in 36/40 patients. These fatty changes were diffuse, focal fatty and diffuse with fatty spare area. Four patients had capsular retraction: 1 patient with HD and 3 patients with metastatic cancer breast. Veno-occlusive disease and biliary sclerosis were not detected.

Preoperative Tumor Studies Using MRI or CT in Patients with Clinically Suspected Insulinoma

Purpose: Insulinomas are rare tumors that originate from the islet cells of the pancreas. The aims of this study were to localize insulinomas preoperatively using CTand/or MRI in correlation with postoperative pathological results. Patients and Methods: Between December 2001 and June 2010, 27 consecutive patients with clinically suspected insulinoma were surgically treated in our university hospital. Preoperative CT (14 of 27 patients) and MRI studies (14 of 27 patients, one patient had both MRI and CT), operation reports, intraoperative ultrasonography reports, and pathological diagnoses were analyzed retrospectively. For each lesion, images were analyzed based on the presence of enhancement or the characteristics of signal intensities. Pathologic correlation was available for all the lesions. Results: The female: male ratio was 2.9, with a mean age of 47.5 years (range 12–82). Preoperative tumor localization was achieved by means of MRI and CT. A focal pancreatic lesion, which was hypointense on T1-weighted sequences, was detected on all the MR images (14 of 27 patients; 100%). These lesions were isointense (4 cases) to slightly hyperintense (10 of 14 cases) on T2-weighted sequences. In T1-weighted fat-suppressed contrast-enhanced sequences, there were two types of enhancement: homogeneously hyperintense lesions (in 10 of 14 cases) or peripherally hyper-, centrally isointense (in 4 of 14 cases). On all the CT images (14 of 27 patients), there was no detectable lesion on precontrast series; on arterial series in 13 of 14 patients (arterial series has not been done in one patient), lesions enhanced hypervascular in contrast to the rest of the pancreas with a mean enhancement of 147 HU (range 113–248) and 95 HU (range 65–141), respectively. On venous series in 13 of 14 patients (venous series has not been done in one patient), there was an enhanced lesion in contrast to the rest of the pancreas with a mean enhancement of 110 HU (range 91–151) and 86 HU (range 65–137), respectively. Intraoperative ultrasonography was performed in 11 of 27 patients to localize the tumor, which correlated with the results of the mentioned preoperative studies. Tumor size ranged from 9 × 11 to 31 × 37 mm. Enucleation was carried out in 14 patients, Whipple in 5, segmental resection in 3 and left distal pancreatectomy in 5 patients. The mortality rate was 0. Pathological findings were insulinoma or neuroendocrine tumors in 26 of 27 cases. One patient had a pathological finding of chronic pancreatic disease with intraepithelial neoplasia (grade 1A). Conclusion: We conclude that the preoperative localization of insulinoma in clinically suspected patients can be made on the basis of MRI and/or CT studies. A hallmark lesion is hypointense in T1-weighted sequences, homogeneously or peripherally hyperintense in T1-weighted fat-suppressed contrast-enhanced sequence using MRI (100% of cases) or/and a hypervascular enhanced lesion on arterial (100% of CT studies) and on venous series using CT (66.7% of CT studies).

Advanced Contrast-Enhanced MRI for Looking Beyond the Lumen to Predict Stroke

Carotid plaque MRI can identify components indicative of stroke risk, including the thin/ruptured fibrous cap and lipid core. Gadolinium contrast, typically administered for routine MR angiography acquisitions, can be used to improve plaque characterization, extending risk assessment beyond the plaque's hemodynamic impact on the lumen. Gadolinium preferentially enhances the cap, improves reliability of vessel wall measurements, and highlights neovessels, improving stroke risk stratification. Additionally, the precontrast series from the contrast-enhanced MR angiography can help identify intraplaque hemorrhage, another important risk marker. Prospective validation of these features is needed to develop a carotid plaque risk profile for clinical implementation.

A survey of routine head CT protocols in Australia.

The choice of scanning protocol in CT will affect the dose delivered to the patient. A nationwide survey of CT operators was carried out in Australia in 1994 to determine the variation in routine head CT protocols. Only 29% of respondents used the supraorbitomeatal (SOM) baseline and thus avoided scanning the eyes. At 74% of sites, the routine protocol included scans both before and after injection of contrast. However, the post-contrast protocol differed from that used in the pre-contrast series in a number of cases. Where 5 mm thick slices were used, the mAs was 16% higher than for 10 mm thick slices. Increased awareness of the influence of baseline, slice thickness/spacing and accompanying exposure factors on patient dose may lead to greater standardization of head CT scanning protocols.

Contrast-Enhanced Computed Tomography to Show Perivesical Extension in Bladder Carcinoma

Fifty-two patients (53 lesions) with muscle invasive carcinoma (T2/T3) of the urinary bladder were examined with computed tomography (CT) before planned total cystectomy. The object of CT was to demonstrate perivesical growth. All patients were examined before and after intravenous injection of contrast medium. The stages obtained from the precontrast and postcontrast scans were compared with the histopathologic stage from the cystectomy specimen. CT staged correctly 35 of the 53 lesions in the precontrast series and 46 of the 53 lesions in the postcontrast series. The improved accuracy from contrast enhancement resulted primarily from fewer cases being overstaged. The use of intravenous contrast medium improved accuracy of CT in evaluation of perivesical tumor growth.