Coronary Plaque Burden at Coronary CT Angiography in Asymptomatic Men and Women.

Purpose To assess the relationship between total, calcified, and noncalcified coronary plaque burdens throughout the entire coronary vasculature at coronary computed tomographic (CT) angiography in relationship to cardiovascular risk factors in asymptomatic individuals with low-to-moderate risk. Materials and Methods This HIPAA-compliant study had institutional review board approval, and written informed consent was obtained. Two hundred two subjects were recruited to an ongoing prospective study designed to evaluate the effect of HMG-CoA reductase inhibitors on atherosclerosis. Eligible subjects were asymptomatic individuals older than 55 years who were eligible for statin therapy. Coronary CT angiography was performed by using a 320-detector row scanner. Coronary wall thickness and plaque were evaluated in all epicardial coronary arteries greater than 2 mm in diameter. Images were analyzed by using dedicated software involving an adaptive lumen attenuation algorithm. Total plaque index (calcified plus noncalcified plaque) was defined as plaque volume divided by vessel length. Multivariable regression analysis was performed to determine the relationship between risk factors and plaque indexes. Results The mean age of the subjects was 65.5 years ± 6.9 (standard deviation) (36% women), and the median coronary artery calcium (CAC) score was 73 (interquartile range, 1-434). The total coronary plaque index was higher in men than in women (42.06 mm(2) ± 9.22 vs 34.33 mm(2) ± 8.35; P < .001). In multivariable analysis controlling for all risk factors, total plaque index remained higher in men than in women (by 5.01 mm(2); P = .03) and in those with higher simvastatin doses (by 0.44 mm(2)/10 mg simvastatin dose equivalent; P = .02). Noncalcified plaque index was positively correlated with systolic blood pressure (ß = 0.80 mm(2)/10 mm Hg; P = .03), diabetes (ß = 4.47 mm(2); P = .03), and low-density lipoprotein (LDL) cholesterol level (ß = 0.04 mm(2)/mg/dL; P = .02); the association with LDL cholesterol level remained significant (P = .02) after additional adjustment for the CAC score. Conclusion LDL cholesterol level, systolic blood pressure, and diabetes were associated with noncalcified plaque burden at coronary CT angiography in asymptomatic individuals with low-to-moderate risk. (©) RSNA, 2015 Online supplemental material is available for this article.

Imaging muscle-invasive and metastatic urothelial carcinoma.

PURPOSE OF REVIEW: Muscle-invasive bladder cancer (MIBC) comprises approximately one-third of bladder cancers and is associated with significant morbidity and mortality. Accurate staging of bladder cancer is essential because of significantly different treatment options and the consequences of inaccurate staging. The current recommended method for staging is transurethral resection of the bladder tumor followed by contrast-enhanced computed tomography (CT). In this review, we discuss cross-sectional imaging approaches used to assess local, nodal, and distant metastases in MIBC. RECENT FINDINGS: Determining the most accurate imaging method for staging MIBC is a contentious issue. CT with contrast is a practical approach; however, there is potential for understaging of small lymph nodes or foci of metastasis. Multiparametric MRI is emerging as the imaging modality of choice in tumor staging, with a reported accuracy of more than 90%. Locoregional lymph node metastasis can also be accurately evaluated using functional MRI and specific contrast agents with paramagnetic characteristics. PET/CT with conventional radiotracers is a common imaging modality for staging distant metastases. SUMMARY: Conventional imaging methods for evaluating MIBC are of limited use. However, recent advances in molecular imaging, targeted contrast agents, and functional MRI have shown promising results for the staging of bladder cancer.

Radiologic reporting of MRI-proven thoracolumbar epidural metastases on body CT: 12-Year single-institution experience.

RATIONALE AND OBJECTIVES: Metastatic epidural masses are an important radiological finding. The purpose of this study is to determine factors associated with non-reporting of thoracolumbar epidural metastases on body CT. MATERIALS AND METHODS: In a study population of 166 patients from a single institution over a 12-year period, 293 body CT examinations were identified which were performed within 30 days before or after a spine MRI diagnosis of epidural metastasis. Associations were sought between patient diagnosis, CT examination characteristics, reporting radiologist (n = 17), and lesion characteristics with respect to whether an epidural metastasis was reported on CT. RESULTS: In retrospective consensus review comprised of 3 radiologists, epidural metastases reported on spine MRI were clearly visible in 80.5% (236/293) of body CT examinations, however 65.3% (154/236) of the body CT reports omitted reporting their presence, even in cases where there was a preceding MRI diagnosis within 30 days (65.4%, 74/113). The identity of the reporting radiologist was statistically significantly associated with the accurate diagnostic reporting of epidural metastasis on body CT (p = 0.04). The only lesion features which were statistically significantly associated with CT reporting were lesion volume (p = 0.03) on noncontrast CT, and lesion volume (p = 0.006) and percentage of spinal canal stenosis (p = 0.001) on intravenous contrast-enhanced CT. The presence or absence of intravenous contrast was not significantly associated with CT reporting (p = 1.0). CONCLUSION: Using spine MRI as the reference standard for the presence of epidural tumor, the majority of body CT reports omit describing thoracolumbar epidural metastases which are clearly visible in retrospect.

Characteristics and Outcomes of Small Cell Lung Cancer Detected by CT Screening.

BACKGROUND: Previous studies with a limited number of patients have reported divergent findings on whether screening can detect small cell lung cancer (SCLC) at an earlier stage and whether there might be a survival benefit. METHODS: This study examined the characteristics of SCLC detected by using low-dose CT (LDCT) screening in the National Lung Screening Trial, a randomized study of individuals at high risk for developing lung cancer comparing LDCT imaging vs chest radiography. SCLC was denoted as screen detected if diagnosed ≤ 1 year of a positive screen or after a longer period but with no time gap between diagnostic procedures of > 1 year; interval detected if diagnosed ≤ 1 year of a negative screen; and nonscreen detected if the subject did not receive any screens or otherwise as postscreening. RESULTS: A total of 143 cases of SCLC were diagnosed, including 49 (34.2%) screen detected, 15 (10.5%) interval detected, and 79 (55.2%) nonscreened/postscreening. Of the screening phase-diagnosed cases (ie, screen or interval detected), a higher proportion of SCLC cases compared with NSCLC cases were interval detected (23% vs 5%; P < .0001). A higher proportion of all SCLC cases compared with NSCLC cases were advanced stage (III/IV: 86% vs 36%; P < .0001). The unfavorable SCLC stage distribution extended across screen-detected (80% stage III/IV), interval-detected (86%), and nonscreened/postscreening (90%) cancers. Among screen-detected SCLC, only 63.3% had ≥ 1 noncalcified nodule in the cancer lobe compared with 85.4% of NSCLC cases (P < .0001). Even with very small LDCT screen-detected nodules, a high proportion of SCLC cases were late stage. There was no significant difference in survival between screen- and interval-detected or postscreening SCLC. CONCLUSIONS: "Early detection" with the use of LDCT imaging had no impact on SCLC outcomes. A successful screening modality should ideally detect SCLC earlier than when it can be detected on LDCT scans.

Paraneoplastic Syndrome With Anti-NMDAR Encephalitis Associated With Ovarian Teratomas.

We report on a 33-year-old woman who had a paraneoplastic syndrome with anti-N-methyl-d-aspartate receptor encephalitis, associated with ovarian teratomas. She presented with acute onset seizures, grandiosity, elevated mood, disorganized thoughts, and paranoia. Cerebral spinal fluid analysis revealed anti-N-methyl-d-aspartate receptor antibodies. A PET/CT was requested, which identified a possible fat and calcification containing right adnexal lesion on the noncontrast CT portion, which was suspicious for a teratoma. Subsequent ultrasound revealed bilateral masses consistent with teratomas. She underwent laparoscopic removal of these masses, which were both confirmed to be mature cystic teratomas on pathology. After surgery, her symptoms progressively improved.

Comparative Evaluation of Three Software Packages for Liver and Spleen Segmentation and Volumetry.

RATIONALE AND OBJECTIVES: This study aims to compare the speed and accuracy of three different software packages in segmenting the liver and the spleen. MATERIALS AND METHODS: The three software packages are Advantage Workstation Solutions (AWS), Claron Technology (Claron) Liver Segmentor, and Vitrea Core Fx (Vitrea). The dataset consisted of abdominal computed tomography scans of 30 patients obtained from the portal venous phase. All but two of the patients had a cancer diagnosis. The livers of 14 patients and the spleens of 24 patients were reported as normal; the remaining livers and spleens contained one or more abnormalities. The initial segmentation times and volumes were recorded in Claron and Vitrea as these created automatic segmentations. The total segmentation times and volumes following corrections were recorded. The livers and spleens were segmented separately by two radiologists who used all three packages. Accuracy was assessed by comparing volumes measured using fully manual segmentation on the AWS. RESULTS: Claron could not segment the spleen in four subjects for the first reader and in two subjects for the second reader. The final mean segmentation times for the liver for both readers were 6.5 and 5.5 minutes for AWS, 4.4 and 3.6 minutes for Claron, and 5.1 and 4.2 minutes for Vitrea. The final mean segmentation times for the spleen were 2.7 and 2.1 minutes for AWS, 2.1 and 1.4 minutes for Claron, and 1.8 and 1.2 minutes for Vitrea. No statistically significant difference was found between the organ volumes measured by the two readers when using Vitrea. The mean differences between the initial and final segmentation volumes ranged from -1.2% to 0.4% for the liver and from -4.0% to 9.8% for the spleen. The mean differences between the automated liver segmentation volumes and the AWS volumes were 2.5%-2.9% for Claron and 4.9%-6.6% for Vitrea. The mean differences between the automated splenic segmentation volumes and the AWS volumes were 5.0%-6.2% for Claron and 10.6%-12.0% for Vitrea. CONCLUSIONS: Both automated packages (Claron and Vitrea) measured liver and spleen volumes that were accurate and quick before manual correction. Volumes for the liver were more accurate than those for the spleen, perhaps due to the much smaller splenic volumes compared to those of the liver. For both liver and spleen, manual corrections were time consuming and for most subjects did not significantly change the volume measurement.

Unilateral Submandibular Gland Atrophy and Sialolithiasis Diagnosed on 99mTc-MIBI SPECT/CT in a Patient With Primary Hyperparathyroidism.

A variety of sequelae of elevated calcium levels are encountered in patients with underlying primary hyperparathyroidism, including stone formation such as calculi in the urinary tract and sialoliths in the salivary glands and ducts. We present a case of a 54-year-old woman with fatigue, myalgia, and poor concentration who was found to have hypercalcemia (corrected calcium, 11.2 mg/dL) and elevated parathyroid hormone level (112 pg/mL), laboratory values consistent with primary hyperparathyroidism. She underwent evaluation with a Tc-MIBI parathyroid SPECT scan that included x-ray CT acquisitions for anatomical localization and attenuation correction.

Molecular Imaging and Precision Medicine: PET/Computed Tomography and Therapy Response Assessment in Oncology.

A variety of methods have been developed to assess tumor response to therapy. Standardized qualitative criteria based on 18F-fluoro-deoxyglucose PET/computed tomography have been proposed to evaluate the treatment effectiveness in specific cancers and these allow more accurate therapy response assessment and survival prognostication. Multiple studies have addressed the utility of the volumetric PET biomarkers as prognostic indicators but there is no consensus about the preferred segmentation methodology for these metrics. Heterogeneous intratumoral uptake was proposed as a novel PET metric for therapy response assessment. PET imaging techniques will be used to study the biological behavior of cancers during therapy.

Molecular Imaging and Precision Medicine in Head and Neck Cancer.

The concept of using tumor genomic profiling information has revolutionized personalized cancer treatment. Head and neck (HN) cancer management is being influenced by recent discoveries of activating mutations in epidermal growth factor receptor and related targeted therapies with tyrosine kinase inhibitors, targeted therapies for Kristen Rat Sarcoma, and MET proto-oncogenes. Molecular imaging using PET plays an important role in assessing the biologic behavior of HN cancer with the goal of delivering individualized cancer treatment. This review summarizes recent genomic discoveries in HN cancer and their implications for functional PET imaging in assessing response to targeted therapies, and drug resistance mechanisms.

Diagnostic Value of 18F-FDG PET/CT Versus MRI in the Setting of Antibody-Specific Autoimmune Encephalitis.

Diagnosis of autoimmune encephalitis presents some challenges in the clinical setting because of varied clinical presentations and delay in obtaining antibody panel results. We examined the role of neuroimaging in the setting of autoimmune encephalitides, comparing the utility of 18F-FDG PET/CT versus conventional brain imaging with MRI. Methods: A retrospective study was performed assessing the positivity rate of MRI versus 18F-FDG PET/CT during the initial workup of 23 patients proven to have antibody-positive autoimmune encephalitis. 18F-FDG PET/CT studies were analyzed both qualitatively and semiquantitatively. Areas of cortical lobar hypo (hyper)-metabolism in the cerebrum that were 2 SDx from the mean were recorded as abnormal. Results: On visual inspection, all patients were identified as having an abnormal pattern of 18F-FDG uptake. In semiquantitative analysis, at least 1 region of interest with metabolic change was identified in 22 of 23 (95.6%) patients using a discriminating z score of 2. Overall, 18F-FDG PET/CT was more often abnormal during the diagnostic period than MRI (10/23, 43% of patients). The predominant finding on brain 18F-FDG PET/CT imaging was lobar hypometabolism, being observed in 21 of 23 (91.3%) patients. Hypometabolism was most commonly observed in the parietal lobe followed by the occipital lobe. An entire subset of antibody-positive patients, anti-N-methyl-d-aspartate receptor (5 patients), had normal MRI results and abnormal 18F-FDG PET/CT findings whereas the other subsets demonstrated a greater heterogeneity. Conclusion: Brain 18F-FDG PET/CT may play a significant role in the initial evaluation of patients with clinically suspected antibody-mediated autoimmune encephalitis. Given that it is more often abnormal when compared with MRI in the acute setting, this molecular imaging technique may be better positioned as an early biomarker of disease so that treatment may be initiated earlier, resulting in improved patient outcomes.

Tissue characterization of the myocardium: state of the art characterization by magnetic resonance and computed tomography imaging.

Late gadolinium enhancement (LGE) is a simple, robust, well-validated method for assessing scar in acute and chronic myocardial infarction. LGE is useful for distinguishing between ischemic and nonischemic cardiomyopathy. Specific LGE patterns are seen in nonischemic cardiomyopathy. Patient studies using T1 mapping have varied in study, design, and acquisition sequences. Despite the differences in technique, a clear pattern that has been seen is that in cardiac disease postcontrast T1 times are shorter. Extracellular volume fraction measured with cardiac computed tomography represents a new approach to the clinical assessment of diffuse myocardial fibrosis by evaluating the distribution of iodinated contrast.

Cardiovascular imaging in 2013: New era of evidence-based medicine with noninvasive imaging.

In 2013, advances in noninvasive imaging methods pushed traditional boundaries in the detection, diagnosis, and functional assessment of coronary artery disease, atherosclerotic plaque, and myocardial function. We highlight five important studies that demonstrate how these developments are allowing medicine to become increasingly evidence-based and personalized.