Various Cranial and Orbital Imaging Findings in Pediatric Abusive and Non-abusive Head trauma, and Relation to Outcomes.

BACKGROUND AND PURPOSE: Differentiating Abusive Head Trauma (AHT) from Non-abusive Head trauma (NAHT) has profound clinical prognostic and legal implications, as certain imaging findings can individually be more suggestive of NAHT, while others are more suggestive of AHT. This study was set out to evaluate for an association between the various imaging findings in AHT with outcome. MATERIAL AND METHODS: Over 7-years, 55 children (age 0-4 years') with head trauma and magnetic resonance imaging (MRI) were included as either: abusive (n = 16), non-abusive (n = 35), or indeterminate (n = 4). Two pediatric neuroradiologists jointly reviewed the imaging. The frequency of imaging findings and their association with ≥6 months' outcome were calculated. RESULTS: Comparing abusive versus non-abusive head trauma, complex subdural hematoma was present in 81% (n = 13/16) and 29% (n = 10/35), hypoxic-ischemic injury in 44% (n = 7/16) and 6% (n = 2/35), and diffuse axonal injury in 12% (n = 2/16) and 26% (n = 9/35), respectively. Susceptibility-weighted imaging (SWI) retinal hemorrhages were absent in non-abusive trauma (0/35), but present in 44% (n = 7/16) of the abusive group. In abuse, simple subdural hematomas were absent. Significant associations were found between the presence of abusive trauma with both hypoxic ischemic insult (OR = 12.83, p = 0.0024) and complex subdural hematoma (OR = 10.83, p = 0.0007). The presence of hypoxic ischemic injury (HII) did correlate significantly with clinical outcome (p = 0.017), while retinal hemorrhages on SWI and complex subdural hematoma did not (p = 0.1696-p = 0.2496). CONCLUSION: Neuroimaging findings can be helpful in discriminating these two conditions on presentation, as well as in helping solidify the suspicion of AHT. Regarding eventual outcome in AHT, the most important predictor is clearly HII.

Threshold for Enhancement in Treated Hepatocellular Carcinoma on MDCT: Effect on Necrosis Quantification.

OBJECTIVE: The objective of our study was to determine whether the conventionally used enhancement threshold of 10 HU for assessing tumor viability in treated hepatocellular carcinoma (HCC) lesions is valid. MATERIALS AND METHODS: To distinguish pseudoenhancement from enhancement in a tumor, we used an in vivo model: The attenuation of 54 hepatic cysts during the unenhanced and portal venous phases of MDCT, similar to what may be observed in HCC with central necrosis, was used to determine the threshold for pseudoenhancement. To validate this model, we compared the attenuation value of liver parenchyma in this cohort with that of 22 HCCs during the late arterial phase of enhancement. We tested the effect of this pseudoenhancement on quantifying necrosis in HCC compared with the conventionally used threshold of 10 HU. RESULTS: Values of enhancing HCC tissue on arterial phase MDCT (mean, 121.3 HU) were comparable with normal liver parenchyma on venous phase MDCT (117.3 HU) (p = 0.27). The threshold of 17.1 HU was the best threshold for the detection of pseudoenhancement in cysts (99% accuracy, 100% sensitivity, and 98% specificity). When this threshold was used instead of the conventional threshold of 10 HU, the mean necrosis proportion of treated HCC increased from 34.0% to 42.6% and the mean viable tumor proportion decreased from 66.0% to 57.4%. The quantification of viable HCC tissue based on 10 HU and the quantification of viable HCC tissue based on 17.1 HU were found to be significantly different (p < 0.0001). CONCLUSION: The threshold of 17.1 HU may be the appropriate cutoff for nonenhancement in a necrotic HCC. Use of this threshold may potentially affect how response to therapy is quantified and categorized.

Optimization of reduced-dose MDCT of thoracic aorta using iterative reconstruction.

OBJECTIVE: To evaluate the contribution of iterative reconstruction on image quality of reduced-dose multidetector computed tomography of the thoracic aorta. METHODS: A torso phantom was scanned using two tube potentials (80 and 120 kVp) and five different tube currents (110, 75, 40, 20, and 10 mAs). All images were reconstructed with both filtered back projection (FBP) and iterative reconstruction. Aortic attenuation, image noise within the thoracic aorta, signal-to-noise ratio, and sharpness of the aortic wall were quantified in the phantom for the two reconstruction algorithms. Data were analyzed using paired t test. A value of P < 0.05 was considered significant. RESULTS: The aortic attenuation was similar for FBP and iterative reconstruction (P > 0.05). Image noise level was lower (P < 0.0001), and image sharpness was higher (P = 0.046) with iterative reconstruction. Signal-to-noise ratios were higher with iterative reconstruction compared with those with FBP (P < 0.0001). Signal-to-noise ratio at 80 kVp with iterative reconstruction (9.8 ± 4.4) was similar to the signal-to-noise ratio at 120 kVp with FBP (8.4 ± 3.3) (P = 0.196). CONCLUSIONS: Less image noise and higher image sharpness may be achieved with iterative reconstruction in reduced-dose multidetector computed tomography of the thoracic aorta.

Pancreatic mucinous cystic neoplasm size using CT volumetry, spherical and ellipsoid formulas: validation study.

CONTEXT: The accuracy for determining pancreatic cyst volume with commonly used spherical and ellipsoid methods is unknown. The role of CT volumetry in volumetric assessment of pancreatic cysts needs to be explored. OBJECTIVES: To compare volumes of the pancreatic cysts by CT volumetry, spherical and ellipsoid methods and determine their accuracy by correlating with actual volume as determined by EUS-guided aspiration. Setting This is a retrospective analysis performed at a tertiary care center. Patients Seventy-eight pathologically proven pancreatic cysts evaluated with CT and endoscopic ultrasound (EUS) were included. Design The volume of fourteen cysts that had been fully aspirated by EUS was compared to CT volumetry and the routinely used methods (ellipsoid and spherical volume). Two independent observers measured all cysts using commercially available software to evaluate inter-observer reproducibility for CT volumetry. MAIN OUTCOME MEASURES: The volume of pancreatic cysts as determined by various methods was compared using repeated measures analysis of variance. Bland-Altman plot and intraclass correlation coefficient were used to determine mean difference and correlation between observers and methods. The error was calculated as the percentage of the difference between the CT estimated volumes and the aspirated volume divided by the aspirated one. RESULTS: CT volumetry was comparable to aspirated volume (P=0.396) with very high intraclass correlation (r=0.891, P<0.001) and small mean difference (0.22 mL) and error (8.1%). Mean difference with aspirated volume and error were larger for ellipsoid (0.89 mL, 30.4%; P=0.024) and spherical (1.73 mL, 55.5%; P=0.004) volumes than CT volumetry. There was excellent inter-observer correlation in volumetry of the entire cohort (r=0.997, P<0.001). CONCLUSIONS: CT volumetry is accurate and reproducible. Ellipsoid and spherical volume overestimate the true volume of pancreatic cysts.

Impact of beta-blockade premedication on image quality of ECG-gated thoracic aorta CT angiography.

BACKGROUND: Thoracic aortic aneurysm is one of the most common aorta pathologies worldwide, which is commonly evaluated by computed tomography angiography (CTA). One of the routine methods to improve the image quality of CTA is heart rate reduction prior to study by beta-blockade administration. PURPOSE: To assess the effect of beta-blockade on image quality of the ascending aorta in electrocardiography (ECG)-gated dual-source CTA (DSCTA) images. MATERIAL AND METHODS: In this retrospective study, ECG-gated thoracic aorta CTA images of 40 patients without beta-blocker administration were compared with ECG-gated images of 40 patients with beta-blockade. Images of the aorta were analyzed objectively and subjectively at three levels: sinus of Valsalva (sinus), sinotubular junction (STJ), and mid ascending aorta (MAA). Quantitative sharpness index (SI) and signal-to-noise ratio (SNR) were calculated and two radiologists evaluated the image quality using a 3-point scale. RESULTS: Mean heart rate in beta-blocker and non-beta-blocker groups was 61.7 beats per minute (bpm) (range, 58.1-63.9 bpm) and 72.9 bpm (range, 69.3-84.1 bpm), respectively (P < 0.05). Aorta wall SI, SNR, and subjective grading were comparable between the two groups at all three levels (P > 0.05). CONCLUSION: Beta-blocker premedication may not be necessary for imaging of ascending aorta with ECG-gated DSCTA.

MDCT of chest, abdomen, and pelvis using attenuation-based automated tube voltage selection in combination with iterative reconstruction: an intrapatient study of radiation dose and image quality.

OBJECTIVE: The purpose of this study was intrapatient comparison of image quality and radiation dose between MDCT scans of the chest, abdomen, and pelvis obtained with attenuation-based automated kilovoltage selection and sinogram-affirmed iterative reconstruction and scans obtained with standard kilovoltage selection and a filtered backprojection image reconstruction algorithm. MATERIALS AND METHODS: One hundred one oncology patients who had undergone two chest, abdominal, and pelvis CT scans within 1 year were imaged with standard tube voltage selection of 120 kVp using a filtered backprojection reconstruction algorithm (protocol 1) and with attenuation-based automated tube voltage selection using an iterative reconstruction algorithm (protocol 2). Radiation dose parameters (volumetric CT dose index [CTDIvol], dose-length product, and effective dose) as well as image noise, signal-to-noise ratio, and contrast-to-noise ratio were compared. Two independent radiologists evaluated image quality and sharpness. Student t test, Fisher exact test, and Wilcoxon signed-rank test were used for analysis. A p value less than 0.05 was considered significant. RESULTS: Mean ± SD CTDIvol values were 19.9 ± 4.43 mGy and 12.53 ± 4.79 mGy for protocols 1 and 2, respectively (p < 0.0001). Effective dose was 38.2% lower on average using protocol 2 compared with protocol 1 (12.08 vs 19.55 mSv; p < 0.0001). Objective image quality parameters were significantly better in protocol 2 (p < 0.0001). Both radiologists found the overall image quality and sharpness to be similar for both protocols (p > 0.05). CONCLUSION: In patients undergoing CT examination of the chest, abdomen, and pelvis, the combination of attenuation-based automated tube voltage selection with iterative reconstruction significantly reduced radiation dose parameters and maintained objective image quality when compared with standard tube voltage selection associated with filtered backprojection reconstruction.

Effect of radiation dose and iterative reconstruction on lung lesion conspicuity at MDCT: does one size fit all?

OBJECTIVE: To evaluate the effect of different acquisition parameters and reconstruction algorithms in lung lesions conspicuity in chest MDCT. METHODS: An anthropomorphic chest phantom containing 6 models of lung disease (ground glass opacity, bronchial polyp, solid nodule, ground glass nodule, emphysema and tree-in-bud) was scanned using 80, 100 and 120 kVp, with fixed mAs ranging from 10 to 110. The scans were reconstructed using filtered back projection (FBP) and iterative reconstruction (IR) algorithms. Three blinded thoracic radiologists reviewed the images and scored lesions conspicuity and overall image quality. Image noise and radiation dose parameters were recorded. RESULTS: All acquisitions with 120 kVp received a score of 3 (acceptable) or higher for overall image quality. There was no significant difference between IR and FBP within each setting for overall image quality (p>0.05), even though image noise was significantly lower using IR (p<0.0001). When comparing specific lower radiation acquisition parameters 100 kVp/10 mAs [Effective Dose (ED): 0.238 mSv] vs 120 kVp/10 mAs (ED: 0.406 mSv) vs 80 kVp/40 mAs (ED: 0.434 mSv), we observed significant difference in lesions conspicuity (p<0.02), as well as significant difference in overall image quality, independent of the reconstruction algorithm (p<0.02), with higher scores on the 120 kV/10 mAs setting. Tree-in-bud pattern, ground glass nodule and ground glass opacity required lower radiation doses to get a diagnostic score using IR when compared to FBP. CONCLUSION: Designing protocols for specific lung pathologies using lower dose acquisition parameters is feasible, and by applying iterative reconstruction, radiologists may have better diagnostic confidence to evaluate some lesions in very low dose settings, preserving acceptable image quality.

Doppler ultrasonography findings of splenic arterial steal syndrome after liver transplant.

OBJECTIVES: Splenic arterial steal syndrome is an important cause of morbidity and mortality after orthotopic liver transplant. Splenic arterial steal syndrome is characterized by arterial hypoperfusion of the graft; and if left untreated, causes ischemic biliary tract injury. Selective arterial embolization is important when treating splenic arterial steal syndrome. Doppler ultrasound has been used to follow-up liver transplant patients. This study sought to analyze alterations in portal vein velocity, peak systolic velocity, and resistivity index of the hepatic artery before diagnosis and after treatment of splenic arterial steal syndrome. MATERIALS AND METHODS: We analyzed the Duplex Doppler ultrasonography results of 20 liver transplant recipients who developed angiographically proven splenic arterial steal syndrome between January 2005 and March 2009. Peak systolic velocity and resistivity index of the hepatic artery were noted during transplant surgery, before selective arterial embolization, and after embolization procedures. RESULTS: A statistically significant decrease was found in peak systolic velocity and resistivity index of the hepatic artery between the intraoperative and pre-embolization values. In contrast to the statistically significant increase in peak systolic velocity of the hepatic artery, there were no significant changes in resistivity index after the selective arterial embolization. Portal vein velocity did not show a statistically significant change between intraoperative and preprocedure values. Portal vein velocity did show a tendency to decrease after coil embolization, but this was not significant. CONCLUSIONS: Doppler ultrasound surveillance is a valuable tool in early detection of hepatic arterial complications. A decrease in peak systolic velocity and resistivity index compared to the corresponding intraoperative data should raise suspicion of splenic arterial steal syndrome. Also Doppler ultrasound can be effectively used to examine the hepatic arterial inflow after selective arterial embolization.

Colorectal liver metastasis after 90Y radioembolization therapy: pilot study of change in MDCT attenuation as a surrogate marker for future FDG PET response.

OBJECTIVE: The purpose of this study was to investigate whether changes in attenuation and size of liver metastatic lesions of colorectal cancer at MDCT 1 month after (90)Y radioembolization treatment are predictive of response at FDG PET 3 months after treatment. MATERIALS AND METHODS: Twenty patients with colorectal liver metastasis consecutively treated with (90)Y radioembolization underwent triphasic MDCT of the liver at baseline and 1 and 3 months after treatment and FDG PET at baseline and 3 months after treatment. Percentage change in tumor attenuation at MDCT (volumetric attenuation), tumor size at MDCT (according to Response Evaluation Criteria in Solid Tumors [RECIST] and World health Organization [WHO] criteria), and volume-weighted maximum standardized uptake value at FDG PET were evaluated. The correlation between FDG PET response 3 months after treatment and response according to RECIST, WHO criteria, and attenuation 1 month after treatment was evaluated. RESULTS: Only 13.3% of patients with FDG PET findings of response 3 months after treatment were identified according to RECIST and WHO criteria 1 month after treatment. According to attenuation criteria at 1 month, however, 53.3% of patients with an FDG PET response at 3 months were identified. A strong association was found between FDG PET response at 3 months and response based on attenuation criteria (odds ratio, 12.4; 95% CI, 0.58-265.3; p = 0.05). CONCLUSION: Early changes in the attenuation of liver metastatic lesions of colon cancer after (90)Y radioembolization treatment may be predictive of future response at FDG PET.

MDCT necrosis quantification in the assessment of hepatocellular carcinoma response to yttrium 90 radioembolization therapy: comparison of two-dimensional and volumetric techniques.

RATIONALE AND OBJECTIVES: The purpose of this study is to evaluate the reproducibility and agreement of tumor necrosis quantification performed by two-dimensional and volumetric methods in a cohort of patients with hepatocellular carcinoma (HCC) treated with yttrium-90 ((90)Y) radioembolization. MATERIALS AND METHODS: Twenty-nine consecutive patients (21 men, 8 women; mean age 66.6 years; age range, 44-90 years) with HCC treated with (90)Y radioembolization that underwent liver multidetector computed tomography (MDCT) were included. Two independent radiologists evaluated the necrosis proportion of the lesions with two-dimensional (2D) measurements according to the European Association for the Study of the Liver guidelines, and with a volumetric method using a voxel-by-voxel analysis. Interobserver reproducibility for each method was assessed by using within-subject coefficients of variation (WSCV), intraclass correlation coefficients (ICC), and Lin's concordance correlation coefficients (LCC). Agreement between both methods was assessed by using the Bland-Altman plot and the paired t-test. RESULTS: The volumetric method was more reproducible (WSCV = 27.8%; ICC = 0.914; LCC = 0.909) than the 2D (WSCV = 43.8%; ICC = 0.723; LCC = 0.841). There was a significant difference in the mean calculated necrosis proportions based on 2D and volumetric methods (P = .0129). CONCLUSION: Voxel-by-voxel quantification of HCC necrosis is a more reproducible method than 2D analysis.

Radiologic assessment of response to therapy: comparison of RECIST Versions 1.1 and 1.0.

Improvements in radiologic imaging technology and therapeutic options available for management of tumors have necessitated the revision of guidelines for the imaging-based assessment of tumor response to therapy. The purpose of this article is to familiarize radiologists with the modifications to the Response Evaluation Criteria in Solid Tumors (RECIST) that have been incorporated in the latest version of the guidelines, RECIST 1.1. The most important differences between this version and the previous one, RECIST 1.0, include reductions in the maximum number of lesions per patient and per organ that may be targeted for measurement, augmentation of the criteria defining progressive disease, additional guidelines for reporting findings of lesions that are too small to measure and for measuring lesions that appear to have fragmented or coalesced at follow-up imaging, new criteria for characterizing lymphadenopathy, new criteria for selecting bone lesions and cystic lesions as targets for measurement, and the inclusion of findings at positron emission tomography among the indicators of disease response.

Evaluation of hepatocellular carcinoma size using two-dimensional and volumetric analysis: effect on liver transplantation eligibility.

RATIONALE AND OBJECTIVES: Milan criteria recommends selection of candidates with hepatocellular carcinoma (HCC) for liver transplantation based on strict tumor size thresholds. The purpose of this study is to compare the effect of two-dimensional and three-dimensional tumor measurements on the selection of candidates for liver transplantation using Milan criteria. MATERIALS AND METHODS: This retrospective Health Insurance Portability and Accountability Act-compliant study was approved by our institutional review board. Patient-informed consent was waived. Forty-five HCCs in 19 patients, evaluated with triphasic multidetector row computed tomography scans, were included in the analysis. The largest diameters in each two-dimensional orthogonal plane (Max2D) and within three-dimensional tumor boundaries (Max3D) were calculated for each lesion. Diameters were compared and the eligibility based on lesion size for liver transplantation was assessed. RESULTS: The mean Max2D diameter of HCC was 3.2 ± 0.9 cm and the mean Max3D diameter was 3.5 ± 1.2 cm. There was a significant difference between the mean Max2D and Max3D diameters (P < .001). Among the 45 lesions, 22 of them (48.9%) were ineligible for transplantation according to Max2D diameter, whereas 29 of them (64.44%) were ineligible when Max3D diameter was applied (P < .001). CONCLUSION: HCC diameter based on 3D measurements is significantly different than the conventional 2D measurements and may affect eligibility for liver transplantation.

CT attenuation of unilocular pancreatic cystic lesions to differentiate pseudocysts from mucin-containing cysts.

CONTEXT: There is extensive overlap among the imaging characteristics of pseudocyst, mucinous cystic neoplasm (MCN) and side branch intraductal papillary mucinous neoplasm (IPMN) on CT images. OBJECTIVE: The purpose of this study was to evaluate the usefulness of attenuation measurement in differentiating pseudocysts from MCN and IPMN of pancreas on CT images. PATIENTS: Seventy-five pathologically proven unilocular pancreatic cysts including 31 pseudocysts, 29 MCN and 15 IPMN imaged with multidetector computed tomography (MDCT) before resection were evaluated. MAIN OUTCOME MEASURES: Attenuation values were measured by conventional region of interest (ROI) method. DESIGN: Attenuation values (in Hounsfield unit, HU) were compared between the cyst pathologies. Receiver operating characteristic (ROC) curve analysis was performed to obtain the best attenuation threshold between mucin-containing cysts and pseudocysts. Correlation between attenuation values and cyst size was assessed. RESULTS: Maximum transaxial diameters of pseudocysts (4.5 cm), MCNs (3.7 cm) and IPMNs (4.0 cm) were comparable (P=0.919). Mean attenuation was 18.9 HU, 13.0 HU and 11.4 HU for pseudocyst, MCNs and IPMNs, respectively. Attenuations were significantly higher in pseudocysts versus mucin-containing (MCN+IPMN) cysts (P=0.001) and comparable between MCNs and IPMNs (P=0.390). ROC curve showed 14.5 HU the best cut-off (accuracy: 73.5%) for differentiating pseudocysts from mucin-containing cysts (P<0.001). Pancreatic cyst attenuation measurement did not significantly correlate with cyst size (r=-0.03, P=0.772). CONCLUSION: Attenuation measurement may help in differentiating pseudocysts from unilocular mucin-containing simple cysts of the pancreas on CT images.

Extraperitoneal pelvic myolipoma.

Myolipoma is a very rare adipocytic tumor occurring most frequently in adults, and usually is located in the retroperitoneum or abdomen. It has been described in the retroperitoneum, spinal cord, orbita, breast, round ligament, subcutaneous tissue, pericardium, rectus sheath of the abdominal wall, and abdominal cavity with attachment to the abdominal wall. Most of these tumors are discovered incidentally and are large when discovered. Radiological findings are nonspecific due to the nonlipomatous component of the tumor. We present radiological findings of a large extraperitoneal pelvic myolipoma adjacent to the anterior abdominal wall, detected incidentally in an elderly woman with a presenting complaint of intractable hiccups.

MRI of central nervous system abnormalities in childhood leukemia.

PURPOSE: To document the imaging abnormalities seen in the central nervous system (CNS) in childhood leukemia or as complications of its treatment. MATERIALS AND METHODS: Magnetic resonance imaging (MRI) of 15 children with neurologic complications of leukemia or its treatment were reviewed retrospectively. The first group consisted of patients with CNS abnormalities detected prior to or during treatment, or within three months after completion of treatment. Patients with CNS complications detected by MRI three months following completion of treatment were included in the second group. RESULTS: Among the 15 children, six had two or more different CNS abnormalities. The imaging abnormalities seen in 12 patients prior to or during treatment, or within three months after completion of treatment included orbital, temporal, cerebellopontine angle, and spinal chloroma; bilateral subdural hematoma in the subacute stage; multifocal intraparenchymal hemorrhage; bilateral retinal hemorrhage and detachment; hematoma in the pons and mesencephalon; PRES (posterior reversible leukoencephalopathy syndrome); bilateral leukemic infiltration of the 3(rd), left 7(th), and 8(th) cranial nerves; and meningeal leukemia. Three months after completion of treatment, three patients had CNS complications including radiation necrosis and secondary brain tumor, osteomyelitis of the L3 vertebra, and meningeal leukemia. CONCLUSION: The wide spectrum of CNS abnormalities that occur during and after treatment for leukemia is related to leukemia and to the treatment method. Because many neurologic complications of leukemia are treatable, early diagnosis is essential.

Various origins of the duplicated middle cerebral artery.

We describe the features of a duplicated middle cerebral artery identified by computed tomographic angiography that originates from a previously undefined origin, ie, from the petrous portion of the internal carotid artery. Recognition of this anomaly is important in patients with a possible aneurysm, which was not present in our patient.

Abnormal diffusion-weighted imaging findings in an adult patient with acute cerebellitis presenting with a normal magnetic resonance imaging.

Acute cerebellitis is an unusual central nervous system complication of infectious disease often due to viral etiology. Diagnosis is aided by neuroimaging studies, actually by magnetic resonance imaging in the first place, which shows increased signal intensity on T2-weighted images. However, conventional magnetic resonance imaging may be unrevealing in some of the cases, and additional workup such as single photon emission computed tomography and diffusion-weighted imaging may be required. We present a case of acute cerebellitis in a 35-year-old woman diagnosed by diffusion-weighted imaging.