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This Month in Radiology

Radiology: Volume 270: Number 1—January 2014 radiology.rsna.org 3A

Radiofrequency Ablation Yields Comparable Survival Rates to Radical Nephrectomy in Patients with Renal Cell Carcinoma

In patients with renal cell carcinoma (RCC) for whom radical nephrectomy poses substantial risk, radiofrequency (RF) ablation is a safe alternative. Takaki et al found in a study of 60 pa-tients with RCC that survival rates were similar in those who underwent RF ablation compared to those who underwent radical nephrectomy (RCC-related survival: 94% vs 100% at 10 years; disease-free survival: 88% vs 84% at 10 years), with a significantly smaller percentage decrease in the estimated glomerular filtration rate in the RF ablation group. The RCC-related and dis-ease-free survival with RF ablation are comparable to those with radical nephrectomy, with little loss of renal function, in the treatment of stage T1b RCC, the researchers concluded. ❚  Page 292

ASIR Significantly Reduces CT Radiation Dose in a Pediatric Cancer Population

A comprehensive method for adaptive statistical iterative reconstruction (ASIR) can reduce pediatric CT radiation dose by an average of 39% for chest CT and 33% for abdominopelvic CT. In a study of 183 patient examinations, Brady et al found that 40% ASIR in conjunction with tube voltage reduction and beam current modulation maximized radiation dose reduction in a pediatric cancer population without changing noise magnitude or image contrast. ASIR for chest and abdominopelvic CT maximizes radiation dose reduction in a pediatric population without changing pre-ASIR image quality standards, the researchers concluded. ❚  Page 223

MR Imaging, Messenger RNA, and DNA Copy Number Variation Map Can Help Identify Biomarkers in Patients with Glioblastoma Multiforme

An integrated DNA and messenger RNA (mRNA) radiogenomic association map shows prom-ise for noninvasive assessment of genomic signatures in patients with glioblastoma multiforme (GBM) by using MR imaging. In a study of 23 patients, Jamshidi et al found that six MR imaging features showed correlation with concordant variations in gene dose and mRNA expression of 34 genes and loci, the majority of which are located to chromosome 1p. Many of these genes have been implicated in other malignancies but have not been implicated in GBM; therefore, they represent targets to further evaluate as biomarkers, the researchers concluded. ❚  Page 212Podcast: Listen to authors discuss this work.

Cortical Microinfarcts on 7-T MR Images Correlate with Alzheimer Disease

Patients with Alzheimer disease (AD) demonstrate more cortical microinfarcts than do con-trol subjects. In a study of 14 patients and 18 control subjects, van Rooden et al found that AD patients had more microinfarcts (mean, 7.2) compared with non-AD subjects (mean, 1.8) on MR images and the number of infarcts correlated with global cognitive performance. The presence of microinfarcts was found to be mainly related to AD rather than the coex-isting presence of cerebral amyloid angiopathy, the researchers noted. These findings open the possibility of obtaining a better understanding of the contribution of microinfarcts to the pathophysiology of diseases, such as AD and vascular dementia, they concluded. ❚  Page 205

Deep Gray Matter Iron Content on R2* MR Images May Be a Biomarker for Disability in Patients with Multiple Sclerosis

Transverse relaxation (R2*) mapping demonstrates deep gray matter changes that have a high correlation to physical disability in patients with multiple sclerosis (MS). In a study of 17 patients with MS and 17 control subjects, who were examined twice, 2 years apart, by using phase im-aging and R2* mapping, Walsh et al found significant changes in deep gray matter iron content in patients with MS, and these changes correlated highly with disease severity. R2* mapping and phase imaging measurements during 2 years are more effective predictor of disease se-verity than single-time measurements. Quantitative iron evaluation of deep gray matter, based on R2* MR imaging measurements, could be useful as a surrogate marker to follow disease disability during short intervals in individuals with MS, the researchers concluded. ❚  Page 186

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THIS MONTH IN Radiology ■ Continued

4A radiology.rsna.org Radiology: Volume 270: Number 1—January 2014

Triple-Phase Four-Dimensional CT Can Help Distinguish Parathyroid Adenoma from Local Mimics

A three-covariate multinomial logistic model derived from a triple-phase four-dimensional (4D) CT scan can help distinguish parathyroid adenoma from thyroid nodules or lymph nodes. In a study of 102 patients with hyperparathyroidism, Hunter et al found that a triple-phase 4D scan of the neck provided improved discriminatory ability compared with a dual-phase CT scan and, based on tissue density and enhancement characteristics, increased confidence in local-izing single- and multigland parathyroid lesions. Accurate localization of abnormal parathyroid tissue allows the choice of minimally invasive surgery over bilateral neck exploration, result-ing in reduced cost and improved patient experience, the researchers concluded. ❚  Page 168

Increased Bowel-Wall Attenuation Is a CT Sign of Ischemia Complicating Small-Bowel Obstruction

For detecting ischemia complicating small-bowel obstruction (SBO), 64-section mul-tidetector CT demonstrates excellent diagnostic accuracy. In a study of 44 patients sus-pected of having SBO, Geffroy et al found that increased bowel-wall attenuation on un-enhanced CT images was a specific sign for ischemia complicating SBO; this sign had 100% specificity and 56% sensitivity. Multidetector CT had a sensitivity of 84% and specificity of 96% for diagnosing ischemia in SBO. Increased unenhanced bowel-wall at-tenuation is a particularly useful sign of bowel-wall ischemia in patients with con-traindications to iodinated contrast agents, the researchers concluded. ❚  Page 159

More than Half of Splenic Vascular Trauma Injuries on CT Scans Are Visualized during Arterial Phase

Addition of arterial phase imaging markedly improves the sensitivity and accuracy of CT in the detection of contained vascular injuries in splenic trauma. In a study of 32 pa-tients with active hemorrhage and 22 with several contained vascular injuries, Uyeda et al found that in 13 of the 22 patients with contained injuries, the vascular lesion was vi-sualized only at the arterial phase of CT. The researchers concluded that the use of arte-rial phase imaging as part of multiphasic whole-body trauma CT markedly increases the sensitivity of CT in the detection of contained vascular injuries in splenic trauma and should be considered to optimize the detection of traumatic splenic injuries. ❚  Page 99

Cardiac MR Imaging during the Cold Pressor Test Demonstrates Myocardial Blood Flow Changes in Healthy Smokers and Nonsmokers

Myocardial perfusion cardiac MR imaging during a cold pressor test (CPT) can allow as-sessment of changes in myocardial blood flow (MBF) globally and in the separate myocar-dial layers in otherwise healthy smokers and nonsmokers. In a study of 10 healthy smok-ers and 19 nonsmokers, Fairbairn et al found that MBF at rest was similar between the nonsmoking and smoking groups (0.97 mL/g/min ± 0.4 vs 0.96 mL/g/min ± 0.3). Non-smokers responded to CPT with a 47% increase in MBF compared with a 27% increase in smokers. The researchers concluded that CPT can be combined with an adenosine stress test in a 60-minute MR examination and this protocol may serve as a noninvasive assess-ment of endothelium-dependent and endothelium-independent perfusion reserve. ❚  Page 82Podcast: Listen to authors discuss this work.

Addition of Tomosynthesis to Conventional Digital Mammography Results in Increased Screening Interpretation Time

Addition of tomosynthesis to conventional digital mammography results in increased time to interpret images from screening examination compared with time to interpret im-ages from digital mammography alone. In a study of 10 radiologists interpreting im-ages from 1502 combined tomosynthesis-mammography examinations and 2163 digi-tal mammography alone, Dang et al found that interpretation time was an average of 0.9 minute longer for the combined examinations and a mean of 10.2 fewer studies were in-terpreted per hour. Estimation of the differential interpretation time should prove use-ful in preparing for the effects on radiologists’ workload and in planning for staffing re-quirements as breast tomosynthesis is implemented, the researchers concluded. ❚  Page 49