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This Month in Radiology

Radiology: Volume 257: Number 1—October 2010 radiology.rsna.org 3A

Digital Tomosynthesis Outperforms Radiography in Detecting Myobacterial Lung Infection

A low-radiation-dose digital tomosynthesis technique performs better than radiogra-phy in the detection of lung lesions, especially cavitary lesions, in patients with pul-monary myobacterial disease. Kim and colleagues found, in a study of 100 partici-pants, that digital tomosynthesis yielded higher sensitivity and better interobserver agreement with a modest increase in radiation dose. Cavity detection may help pre-dict prognosis, noted the researchers, and early detection may afford the opportuni-ty for early treatment before bacteriology results can confirm diagnosis. ❚  Page 269

Epidural Hematoma Subtype Likely to Follow Benign Clinical Course after Blunt Head Trauma

A unique subtype of blunt head trauma-associated anterior temporal epidural he-matoma (EDH) may remain indolent with little to no intervention. Among 200 pa-tients with biconvex, high-attenuation, extraaxial collections typical for acute EDH, Gean and colleagues retrospectively identified a subgroup of 21 patients whose EDH was located at the anterior aspect of the middle cranial fossa and exhibited be-nign natural history, even without treatment. Patients in good neurologic condition with these isolated hematomas may be followed up clinically with limited follow-up CT imaging and relatively early discharge, the researchers concluded. ❚  Page 212

Dual-Energy CT Helps Differentiate Contrast Material Staining from Intracerebral Hemorrhage

Dual-energy CT is highly sensitive and specific for distinguishing areas of hyperattenuation secondary to contrast material staining from intracerebral hemorrhage in patients who have received intraarterial or intravenous iodinated contrast material. Using a three-ma-terial decomposition algorithm to obtain virtual unenhanced and iodine overlay images in 16 patients with acute stroke and two patients with head trauma, Gupta and colleagues found that dual-energy CT yielded 100% sensitivity, 91% specificity, and 93% accuracy. The researchers concluded that distinction with dual-energy CT could be particularly helpful in patients who have recently undergone intraarterial stroke therapy. ❚  Page 205

General Population Screening May Be Ineffective Against Ovarian Cancer

Diagnostic workup for incidental adnexal masses—relatively common in asymptomat-ic women undergoing CT colonography screening—rarely reveals early stage ovarian cancer, and a normal finding at CT is not protective against short-term ovarian can-cer development. In a cohort of 2869 women, 118 of whom had incidental adnexal masses, Pickhardt and colleagues found that no cancers were prospectively identified, although four cases of ovarian cancer developed after negative CT results. This supports the notion that the time window for presymptomatic ovarian cancer detection may be too narrow for screening in the general population, the researchers noted. They con-cluded that more refined risk assessment may be warranted, with better identification of women at higher risk and less aggressive management of low-risk cases. ❚  Page 144

Contrast-enhanced CT and PET/CT Useful in Ovarian Cancer Prognosis

Contrast-enhanced CT and PET/CT have similar potential for aiding prognosis in women with recurrent ovarian cancer. In a retrospective study of 35 women who underwent con-trast-enhanced CT and PET/CT before exploratory surgery, Sala and colleagues found that the size, number, and maximum standardized uptake value of peritoneal lesions and distant lymph node metastases were predictors of disease progression. These factors could serve as potential biomarkers for ovarian cancer survival, the researchers concluded. ❚  Page 125

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THIS MONTH IN RADIOLOGY ■ CONTINUED

4A radiology.rsna.org Radiology: Volume 257: Number 1—October 2010

Isoattenuating Pancreatic Adenoarcinoma May Have Better Outcomes than Other Pancreatic Cancers

Pancreatic adenocarcinoma with visually isoattenuating features at dynamic contrast-en-hanced CT represents a small but meaningful subset of pancreatic cancers, with different pathologic features and a better survival rate. In 644 patients, Kim and colleagues identified 35 isoattenuating cancers that demonstrated lower tumor cellularity, more frequent intra-tumoral acinar tissue and islet cells, and less prominent tumor necrosis and that had better patient survival after curative-intent surgery. MR and PET/CT were moderately sensitive for detecting these adenocarcinomas and could be suitable as subsequent examinations when the patients are suspected of having adenocarcinomas at CT, the researchers noted. ❚  Page 87

Calcium Score May Predict Subclinical Coronary Artery Disease

Patients with subclinical atherosclerosis as demonstrated by higher coronary artery calcium may be more likely to have future regional wall motion abnormalities and re-duced systolic and diastolic function. In a cohort of 386 patients—part of the larger South Bay Heart Watch clinical study—who underwent functional analysis with MR im-aging and calcium scoring with CT, Colletti and colleagues found that higher coronary artery calcium score was associated with a slightly lower left ventricular ejection frac-tion and increased likelihood of regional wall motion abnormalities. The researchers con-cluded that calcium score may be a marker of previous and possible subclinical coro-nary artery disease that is not predicted by specific recorded coronary events. ❚  Page 64

Apparent Diffusion Coefficient May Be Used to Predict Chemotherapy Response in Patients with Invasive Breast Cancer

Patients with breast cancer who have a low pretreatment apparent diffusion coef-ficient (ADC) at diffusion-weighted MR imaging tended to respond better to che-motherapy. In a study of 53 women with 53 invasive breast cancers, Park and col-leagues found that pretreatment ADCs were significantly lower in responders than in nonresponders. The researchers concluded that diffusion-weighted MR imaging may help to individualize treatment and prevent ineffective chemotherapy. ❚  Page 56

Computer-aided Detection Associated with Considerable Increase in Mammography Interpretation Time

Computer-aided detection (CAD) may increase the time radiologists spend on interpret-ing screening mammograms, while having less determinable effects on radiologists’ ef-ficiency. In a study of radiologists who interpreted 267 mammograms without and then with CAD, Tchou and colleagues found that radiologists spent 19% more time inter-preting screening mammograms with CAD than without. Recall rate increased by 11%, while radiologists reported increased confidence in 14% of cases and decreased confi-dence in 8% of cases. The reported increase in interpretation time is an important con-sideration when evaluating the efficiency of CAD, the researchers concluded. ❚  Page 40

Radiation Risk from Breast-specific Gamma Imaging and Positron Emission Mammography Comparable to 40 Years of Mammography Screening

A single breast-specific gamma imaging (BSGI) or positron emission mammogra-phy (PEM) examination is associated with a fatal radiation-induced cancer risk higher than or comparable to that of annual screening mammography in women aged 40–80 years. Hendrick compared lifetime attributable risks of the imaging modalities us-ing data from recent peer-reviewed literature and age-dependent risks in the Na-tional Academy of Sciences’ BEIR VII report. When referring patients for new im-aging techniques such as BSGI or PEM, physicians should consider the risks and benefits and communicate them fully to patients, Hendrick concluded. ❚  Page 246