Radiology News
Detection of Aortic Regurgitation with 64-slice Multidetector Computed Tomography (MDCT)
An article in this months Academic Radiology sought to determine the diagnostic accuracy of 64-row multidetector cardiac computed tomography (MDCT) in detecting aortic regurgitation (AR) on prospectively acquired images with trans-thoracic echocardiography (TTE) as a reference standard. The sensitivity, specificity, positive predictive value, and negative predictive value of MDCT were 100%, 85.7%, 93.5%, and 100%, respectively, showing that MDCT data acquired for the coronary artery evaluation can be used for the detection of aortic regurgitation with high diagnostic accuracy without additional scanning or radiation and can support appropriate referral for TTE.
Routine Ultrasound and Limited Computed Tomography for the Diagnosis of Acute Appendicitis
Acute appendicitis continues to be a challenging diagnosis. Preoperative radiological imaging using ultrasound (US) or computed tomography (CT) has gained popularity as it may offer a more accurate diagnosis than classic clinical evaluation. The optimal implementation of these diagnostic modalities has yet to be established. The aim of the present study was to investigate a diagnostic pathway that uses routine US, limited CT, and clinical re-evaluation for patients with acute appendicitis. Positive and negative predictive values for the clinical diagnosis of appendicitis were 63 and 98%, respectively; for US 94 and 97%, respectively; and for CT 100 and 100%, respectively. The negative appendicitis rate was 3.3%, the perforation rate was 23.5%, and the missed perforated appendicitis rate was 3.4%. This study showed a diagnostic pathway using routine US, limited CT, and clinical re-evaluation for patients with acute abdominal pain can provide excellent results for the diagnosis and treatment of appendicitis.
Computed tomographic colonography in the diagnosis of colorectal cancer
This study aimed to determine the sensitivity of computed tomographic colonography (CTC) in diagnosing colorectal cancer and to explore the reasons why these cancers are missed on CTC. Patients who underwent CTC in the 56-month period from 1 January 2004 to 1 September 2008, and all cases of colorectal cancer recorded in the National Cancer Registry database from 1 January 2004 to 1 December 2008, were identified. Overall the sensitivity of 95 per cent for CTC in the diagnosis of colorectal cancer compares favourably with that of double-contrast barium enema (92 per cent) and colonoscopy (94 per cent).
CT evaluation of the low severity cervical spine trauma: When is the scout view enough?
The aim of the current study was to compare the diagnostic information obtained from a helical CT examination in low severity cervical spine trauma with that from a lateral CT scout view. Overall sensitivity and specificity of scout view was 70% and 100%, respectively. There were three false negative and one false positive cases. The effective dose value was estimated to be 0.02 mSv which is at least two orders of magnitude lower than that from a CT scan. When clinical examination is not suggestive of a C1–C2 fracture, adequate depiction of an intact cervical spine at the scout view, without proceeding to a full CT scan, is a sufficient dose and time-effective imaging approach.
Diagnosis of Necrotizing Soft Tissue Infections by Computed Tomography
In contrast to previous beliefs, an article in this weeks Archives of Surgery hypothesized that computed tomography (CT) scanning is sensitive and specific for the diagnosis of necrotizing soft tissue infections (NSTIs). Patients who were clinically suspected of having NSTIs from January 1, 2003, through April 30, 2009, and who underwent imaging with a 16- or 64-section helical CT scanner were studied. Of 67 patients with study inclusion criteria, 58 underwent surgical exploration, and NSTI was confirmed in 25 (43%). The remaining 42 patients had either nonnecrotizing infections during surgical exploration (n = 33) or were treated nonoperatively with successful resolution of the symptoms (n = 9). The sensitivity of CT to identify NSTI was 100%, specificity was 81%, positive predictive value was 76%, and negative predictive value was 100% concluding that a negative CT result reliably excludes the diagnosis of NSTI while a positive CT result correctly identifies the disease with a high likelihood.
High-resolution ultrasound in the evaluation and prognosis of Bell's palsy
Bell's palsy is a commonly encountered paralysis of the facial nerve occurring worldwide. Prognosis for Bell's palsy is good, but the proportion of patients with poor outcomes may reach 30%. Ultrasound (US) may provide a novel approach for evaluating and prognosticating Bell's palsy, in comparison with known electrophysiological techniques. A study out of the European Journal of Neurology measured the diameter of the distal facial (VII) nerve using US in patients with Bell's palsy treated with prednisolone, in comparison with healthy controls. Overall it was found that the diameter of the distal VII nerve is a good predictor of favorable (positive predictive value: 100%) and bad outcomes (negative predictive value: 77%) in Bell's palsy at 3 months after clinical presentation. US was also found to be superior to VII nerve conduction and blink reflex studies in outcome prediction.
Radiation Risks Nearly Double for Younger CT Scan Patients
Radiation risks associated with abdominal and pelvic CT scans are twice as high for younger patients as older patients, a new study finds. The study found that the estimated radiation risk for a 31-year-old (0.91 per 1,000) was about double that for a 74-year-old (0.47 per 1,000). The median radiation risk to 25 males was 0.61 per 1,000 and for 26 females was 0.74 per 1,000. The study was to be presented Monday at the American College of Radiology/American Roentgen Ray Society annual meeting in San Diego.
CT Angiography Cuts Costs in Screening for CAD
Noninvasive computed tomography angiography (CTA) can be a cheaper alternative to invasive cardiac catheterization in diagnosing coronary artery disease, researchers performing a decision-tree analysis said.
Using coronary CTA to screen for coronary artery disease reduced the diagnostic cost per patient by an average of $759 for patients who test positive on a stress test, but who otherwise have no symptoms and are at a less than 50% chance of significant coronary artery disease, according to an online report in the American Journal of Roentgenology.
What is the complementary role of ultrasound evaluation in the diagnosis of acute appendicitis after CT?
A study in this months European Journal of Radiology estimated the complementary role of ultrasound evaluation in the diagnosis of acute appendicitis after abdominoplevic CT. A total of 104 patients initially underwent abdominopelvic CT before appendix US due to acute abdominal pain. Appendix US images and their radiologic reports were also evaluated retrospectively.In the 41 patients of normal looking appendix on CT, US showed acute appendicitis in five patients (12.2%, 5 of 41). US reevaluation enables us to avoid misdiagnosis of appendicitis on CT and improve diagnostic accuracy of acute appendicitis.
Detection of elevated right atrial pressure using a simple bedside ultrasound measure
Accurate assessment of right atrial pressure (RAP) often requires invasive measurement. With normal RAP, Valsalva increases right internal jugular vein (RIJV) cross sectional area (CSA) 20% to 30%. With high RAP, when venous compliance is low, an article this months American Heart Journal hypothesized that the increase in CSA would be blunted and could be detected non-invasively with bedside ultrasound. Overal it showed that an increase in RIJV CSA >17% during Valsalva effectively rules out elevated RAP. This simple bedside technique may be useful to assess central venous pressure and reduce the need for invasive pressure measurement.
The Status of the Fourth Ventricle and Ambient Cisterns Predict Outcome in Moderate and Severe Traumatic Brain Injury
Computed tomography (CT) of the head has become the diagnostic tool of choice, particularly for moderate and severe traumatic brain injury (TBI). Various CT characteristics are associated with outcome, and may therefore be used as outcome predictors. One of the most prominent predictors appears to be the status of the basal cisterns. This study describes the prognostic value of the appearance of individual cisterns and ventricles in relation to that of the basal cisterns. Its results showed that the absence (complete obliteration), but also compression of the ambient cisterns and/or the fourth ventricle were strongly related to unfavorable outcome and death and emerged as the only significant outcome predictors after multivariate analysis.
Contrast-enhanced ultrasound is helpful in the differentiation of malignant and benign breast lesions
A study out of the European Journal of Radiology evaluate the significance of contrast-enhanced ultrasound (CEUS) examination in differential diagnosis of malignant and benign breast lesions. Following SonoVue administration different perfusion phases could be identified. In the early phase, CEUS identified 91.1% of malignant tumors characterized by a claw-shaped enhancement, while 83.9% of benign tumors had a homogeneous enhancement, with a statistically significant difference between the two enhancement patterns. Moreover, contrast medium persistence in the late phase was helpful in the identification of benign and malignant tumors contrast medium was present in 88.9% of malignant tumors, while in only 9.7% of the benign tumors. The study showed that various parametric imaging color maps for peak intensity and time to peak were mostly suggestive of malignancy, while quite uniform peak intensity and time to peak of color maps were the characteristic of benign tumors. The study also found that malignant lesions presented with a higher maximum intensity signal than benign ones on the time–intensity curves.
NIH policy urges CT makers to track radiation dose
The National Institutes of Health plans to require that all makers of CT and other radiation-producing scanners used at NIH clinics have software that tracks a patient's radiation dose and logs it into an electronic medical record.The new policy arises from patient concerns about studies suggesting that repeated exposure to radiation from diagnostic tests may raise their risk of cancer, said Dr. David Bluemke, director of radiology and imaging sciences at the NIH Clinical Center. The policy was announced on Monday in the Journal of the American College of Radiology.
Radiation Dose Associated With Common Computed Tomography Examinations Varies Greatly By Institution
Archives of Internal Medicine Abstract
Use of computed tomography (CT) for diagnostic evaluation has increased dramatically over the past 2 decades. Even though CT is associated with substantially higher radiation exposure than conventional radiography, typical doses are not known. Radiation doses varied significantly between the different types of CT studies. The overall median effective doses ranged from 2 millisieverts (mSv) for a routine head CT scan to 31 mSv for a multiphase abdomen and pelvis CT scan. Within each type of CT study, effective dose varied significantly within and across institutions, with a mean 13-fold variation between the highest and lowest dose for each study type.
CT, Ultrasound Equivalent in Pediatric Pneumonia
In pediatric patients with complicated pneumonia, chest ultrasound works as well as CT scanning to detect complications such as loculated pleural effusion, lung necrosis, or lung abscess, researchers said. In a retrospective cohort of children with complicated pneumonia and parapneumonic effusion, the two imaging methods were similar in their ability to detect loculated effusion and lung necrosis or abscess, according to Terry Levin, MD, of Albert Einstein College of Medicine in New York, and colleagues.
Scans Shed New Light on Concussions
Researchers say they've discovered a new way to detect evidence of brain damage after concussions, potentially paving the way toward more effective treatments for head injuries. By detecting damage from concussions early with the help of the latest brain scanning technology, doctors could begin cognitive rehabilitation treatment and prevent complications, study author Dr. Michael Lipton, an associate director of the Gruss Magnetic Resonance Research Center at Albert Einstein College of Medicine of Yeshiva University, explained in a university news release.
Younger Americans overexposed to radiation risk
Younger Americans are being exposed to worrisome amounts of radiation from medical scans that increase their risk of cancer, U.S. researchers said on Wednesday. They said the cumulative risk of repeated exposure to radiation from medical scans is a public health threat that needs to be addressed.
Collateral Vessels on CT Angiography Predict Outcome in Acute Ischemic Stroke
Stroke
Despite the abundance of emerging multimodal imaging techniques in the field of stroke, there is a paucity of data demonstrating a strong correlation between imaging findings and clinical outcome. Prehospital symptoms were unrelated to occlusion or collateral status. In cases, 37.5% imaged within 1 hour were found to have diminished collaterals versus 12.1% imaged at 12 to 24 hours (P=0.047). No difference in worsening was seen between cases and control subjects with adequate collaterals, but cases with diminished sylvian and leptomeningeal collaterals experienced greater risk of worsening compared with control subjects measured either by admission to discharge.
MRI touted as endoscopic alternative for Crohn’s disease
Positive study findings have led Spanish researchers to propose that magnetic resonance (MR) could be used as an alternative to endoscopy to assess the activity and severity of ileocolonic Crohn’s disease (CD). Quantitative MR changes such as wall thickening, contrast signal intensity, and relative contrast enhancement closely paralleled the severity of endoscopic lesions, say J Panes (Hospital Clinic of Barcelona) and colleagues.
The Role of the Meniscus in Knee Osteoarthritis: a Cause or Consequence?
The Radiologic Clinics of North America
A meniscal tear can lead to knee osteoarthritis (OA), but knee OA can also lead to a spontaneous meniscal tear through breakdown and weakening of meniscal structure. A degenerative meniscal lesion in the middle-aged or older patient could suggest early stage knee OA and should be treated accordingly. Surgical resection of nonobstructive degenerate lesions may only remove evidence of the disorder while the OA and associated symptoms proceeds.
