Diagnostic Ultrasound Examination Research Articles

Predicting poor outcome from simple ankle injuries: a prospective cohort study.

Sprained ankles are common and when there are no signs or evidence of a fracture, conventional management is conservative. At present, there are no clinical markers to identify those that may develop persisting instability and disability that would require rehabilitation or surgery. To investigate the nature and extent of soft tissue ankle injuries, and to consider whether the anatomical severity of injury can predict functional outcome. Patients attending a local Accident and Emergency Department in Oxford with an acute ankle injury with no clinical requirement for radiographs, or where radiographs were normal, were invited into the study. Within 5 days, patients underwent a diagnostic ultrasound examination, a cone beam CT study and a disability assessment. Ultrasound and physiotherapy assessments were repeated at 3 and 6 months. 100 patients were recruited and grouped based upon injuries. 58 had simple ankle injuries, 21 complex, 19 had significant fractures and 2 were excluded from further follow up analysis. There were no clinically significant differences in pain, disability or functional outcomes between the groups at all points of the study. Medium to long term clinical outcomes were not solely determined by the severity of injury. Some patients with simple injuries were seen to have ongoing problems, whereas some with complex injuries recovered completely in a shorter period. Advances in knowledge: The severity of an ankle injury determined by radiological imaging does not necessarily dictate the severity of a patient's symptoms and the trajectory of their recovery.

Agreement Between an Automated Volume Breast Scanner and Handheld Ultrasound for Diagnostic Breast Examinations.

To compare the agreement and interobserver variability of diagnostic handheld ultrasound (US) and a single volume on an automated breast volume scanner (ABVS) and to determine whether there was a significant difference if the ABVS was used by a sonographer or mammographic technologist. Ninety patients scheduled for diagnostic US examinations were randomized to either handheld US or the ABVS first. The AVBS was randomized between a sonographer and a mammographic technologist performing the study. The studies were blinded, randomized, and read by 2 radiologists. The lesion with the highest Breast Imaging Reporting and Data System (BI-RADS) score was used in the analysis. Final diagnoses were made by core biopsy or follow-up for 2 years. Lesions included 9 malignant and 81 benign. The 90 patients had a mean age ± SD of 53.1 ± 16.3 years. The κ value for agreement between the ABVS and handheld US was 0.831 (95% confidence interval, 0.744-0.925), whereas the global agreement for a 7-point BI-RADS score was 0.488 (0.372-0.560). The agreement between the ABVS and handheld US was nearly the same when the ABVS was used by a mammographic technologist (κ = 0.858 [0.723-0.963]) or sonographer (κ = 0.803 [0.596-1.000]; P = .47). The areas under the receiver operating characteristic curves for characterization by the ABVS were 0.91 (0.84-0.96) for reader 1 and 0.91 (0.83-0.96) for reader 2; those for handheld US were 0.91 (0.84-0.96) for reader 1 and 0.83 (0.74-0.90) for reader 2, with no statistical difference. The agreement based on pathologic images was κ = 0.831 (0.718-0.944); for handheld US, κ = 0.795 (0.623-0.967); and for the AVBS, κ = 0.869 (0.725-1.000). Performing a single-view diagnostic ABVS examination has good agreement with a handheld diagnostic US workup. There is no difference if the ABVS is used by a sonographer or mammographic technologist.

Prediction of Amnionicity Using the Number of Yolk Sacs in Monochorionic Multifetal Pregnancy.

The purpose of this article was to evaluate the accuracy of predicting amnionicity using the number of yolk sacs by diagnostic ultrasound examination in monochorionic (MC) multifetal pregnancies between 7 + 0 and 9 + 6 gestational weeks. A total of 97 patients with MC multifetal pregnancies underwent early ultrasound examination from 2004 to 2014 at Cheil General Hospital and Women's Healthcare Center. All patients for whom the number of yolk sacs was reported were included in this study. We compared the number of yolk sacs with amnionicity confirmed by an intertwine membrane. Overall, there was a 9.3% (9 cases) discrepancy in number of yolk sacs and amnionicity (4.3% for monochorionic diamniotic, 36.4% for monochorionic monoamniotic, and 33% for monochorionic triamniotic). Among the 9 cases with discrepancies, 4 cases with 2 yolk sacs were confirmed as monoamniotic pregnancies and 4 MC twin pregnancies showing a single yolk sac were diagnosed as diamniotic twin pregnancies. One case with 2 yolk sacs was identified as a triamniotic triplet pregnancy. In 9.3% of MC gestations, the number of yolk sacs was not correlated with the number of amnions in our study. To determine amnionicity in MC multifetal pregnancies, we recommend careful evaluation not of the number of yolk sacs but the presence or absence of intertwine dividing membrane after 8 gestational weeks.

Pilot study of parathyroid glands in adult and pediatric subjects exposed to ionizing radiation after the ChNPP accident, methodology of parathyroid diagnostic ultrasound

Estimation of the parathyroid hyperplasia prevalence after the ChNPP accident in adults exposed to ion izing radiation and their descendants using the diagnostic ultrasound and its methodology elaboration. The pilot prospective study of the prevalence of parathyroid hyperplasia among the Chornobyl Nuclear Power Plant (ChNPP) accident adult survivors (n=686) and their descendants (54 children) was performed using diagnostic ultrasound examination of thyroid and parathyroids. Among the study subjects there were 339 ChNPP accident clean up workers (ACUW), 32 persons were evacuated from the 30 km exclusion zone and 224 ones were included to the control group. Diagnostic ultrasound of thyroid and parathyroids was performed according to the standard method. Additionally, in children with parathyroid hyperplasia an additional assay of 25 hydroxyvitamin D levels in serum was performed. In calculating the statistical significance, its level p < 0.05 was considered statistically significant. Parathyroids are a few small but critically important endocrine glands that synthesize parathyroid hormone, regulating mainly phosphoric calcium metabolism. Insufficient (hypoparathyroidism) or excessive (hyperparathy roidism) function of parathyroids is harmful to the patients affecting the state of nervous and cardiovascular sys tem. Parathyroidss can accumulate isotopes of cesium, strontium and radioactive iodine. The available data testify to an increased incidence of clinically significant hyperplasia of parthyroids (more than 9 mm in adults and more than 5 mm in children) among persons exposed toionizng radiation as a result of the accident at the ChNPP (28.64%) and their descendants (23.8-70.6%). First of all are concerned those adults who live in contaminated areas in comparison with the control group (24.15% in not irradiated). Evacuees from the 30 km exclusion zone being the category of people who were exposed to the absorbed iodine isotopes in the first days of the Chernobyl accident are the another risk group. These data demonstrate sensitivity of parathyroidss to the impact of incorpo rated isotopes (iodine, cesium and strontium), which in the long term exposure create conditions for structural and functional changes in regulation of phosphorous calcium metabolism being the basis for a significant prevalence of osteopenia and osteoporosis in irradiated individuals and their descendants. A number of further studies are required to clarify the findings and to disclose the hormonal mechanisms of radiation effects on parathyroids. Parathyroid glands are radiosensitive and susceptible to effects of strontium, cesium and iodine iso topes, which cause parathyroid irradiation and subsequent structural and functional changes, being a prerequisite for development of osteopenia and osteoporosis in the ChNPP accident survivors and their descendants. High inci dence of parathyroid hypertrophy is found in the inhabitants of the radiation contaminated territories (long term irradiation by cesium isotopes), as well as in evacuated from the 30 km exclusion zone (irradiation by iodine iso topes in the early days of the accident).

Maternal Hydration with Genetic Ultrasound Increases Scan Quality, Decreases Exam Duration, and Lowers Repeat Exams

Amniotic fluid volume (AFV) has a major impact on the prenatal diagnostic ultrasound examination. Fetal crowding due to low AFV gives rise to poor quality scans, limited anatomical views and longer exam duration. Literature review by Gizzo, Noventa et al., from 1991 thru 2014, suggests “Maternal Hydration may be a safe and useful strategy to improve AFV.” In this study, we examined how oral hydration could increase the AFV for the genetic ultrasound, and whether patient hydration rather than full bladder achieves better imaging outcomes. The focus of this study is to further previous research performed by Jacobson. The preliminary study examined 68 patients in 2 different groups (control vs. hydration) to compare the effects of maternal hydration on Amniotic Fluid Index (AFI), as outlined by Phlen, during the 20 week genetic scan. That study found a 35% increase in AFI within the hydration group. Based on those findings, the current study was conducted to examine the relationship of AFI to maternal and gestational age, parity, adipose tissue and quality diagnostic scan time. Data was collected from 136 patients during genetic ultrasound. Patients with higher AFI showed better image quality, fewer repeat exams and shortened scan times. Maternal hydration as preparation for genetic ultrasound is effective to increase quality in diagnostic data, decrease scan time, lower repeat exams, and eliminates the painful full bladder technique.

AIUM Practice Guideline for the Performance of Diagnostic and Screening Ultrasound Examinations of the Abdominal Aorta in Adults.

AIUM Practice Guideline for the Performance of Diagnostic and Screening Ultrasound Examinations of the Abdominal Aorta in Adults.

Point of care ultrasonography in haemophilia care: recommendations for training and competency evaluation.

Point of care ultrasonography in haemophilia care: recommendations for training and competency evaluation.

Ultrasound for fetal assessment in early pregnancy

Diagnostic ultrasound is a sophisticated electronic technology, which utilises pulses of high-frequency sound to produce an image. Diagnostic ultrasound examination may be employed in a variety of specific circumstances during pregnancy such as after clinical complications, or where there are concerns about fetal growth. Because adverse outcomes may also occur in pregnancies without clear risk factors, assumptions have been made that routine ultrasound in all pregnancies will prove beneficial by enabling earlier detection and improved management of pregnancy complications. Routine screening may be planned for early pregnancy, late gestation, or both. The focus of this review is routine early pregnancy ultrasound. To assess whether routine early pregnancy ultrasound for fetal assessment (i.e. its use as a screening technique) influences the diagnosis of fetal malformations, multiple pregnancies, the rate of clinical interventions, and the incidence of adverse fetal outcome when compared with the selective use of early pregnancy ultrasound (for specific indications). We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 March 2015) and reference lists of retrieved studies. Published, unpublished, and ongoing randomised controlled trials that compared outcomes in women who experienced routine versus selective early pregnancy ultrasound (i.e. less than 24 weeks' gestation). We have included quasi-randomised trials. Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. We used the Review Manager software to enter and analyse data. Routine/revealed ultrasound versus selective ultrasound/concealed: 11 trials including 37,505 women. Ultrasound for fetal assessment in early pregnancy reduces the failure to detect multiple pregnancy by 24 weeks' gestation (risk ratio (RR) 0.07, 95% confidence interval (CI) 0.03 to 0.17; participants = 295; studies = 7), moderate quality of evidence). Routine scans improve the detection of major fetal abnormality before 24 weeks' gestation (RR 3.46, 95% CI 1.67 to 7.14; participants = 387; studies = 2,moderate quality of evidence). Routine scan is associated with a reduction in inductions of labour for 'post term' pregnancy (RR 0.59, 95% CI 0.42 to 0.83; participants = 25,516; studies = 8), but the evidence related to this outcome is of low quality, because most of the pooled effect was provided by studies with design limitation with presence of heterogeneity (I² = 68%). Ultrasound for fetal assessment in early pregnancy does not impact on perinatal death (defined as stillbirth after trial entry, or death of a liveborn infant up to 28 days of age) (RR 0.89, 95% CI 0.70 to 1.12; participants = 35,735; studies = 10, low quality evidence). Routine scans do not seem to be associated with reductions in adverse outcomes for babies or in health service use by mothers and babies. Long-term follow-up of children exposed to scan in utero does not indicate that scans have a detrimental effect on children's physical or cognitive development.The review includes several large, well-designed trials but lack of blinding was a problem common to all studies and this may have an effect on some outcomes. The quality of evidence was assessed for all review primary outcomes and was judged as moderate or low. Downgrading of evidence was based on including studies with design limitations, imprecision of results and presence of heterogeneity. Early ultrasound improves the early detection of multiple pregnancies and improved gestational dating may result in fewer inductions for post maturity. Caution needs to be exercised in interpreting the results of aspects of this review in view of the fact that there is considerable variability in both the timing and the number of scans women received.

Conditionally Increased Acoustic Pressures in Nonfetal Diagnostic Ultrasound Examinations Without Contrast Agents: A Preliminary Assessment.

The mechanical index (MI) has been used by the US Food and Drug Administration (FDA) since 1992 for regulatory decisions regarding the acoustic output of diagnostic ultrasound equipment. Its formula is based on predictions of acoustic cavitation under specific conditions. Since its implementation over 2 decades ago, new imaging modes have been developed that employ unique beam sequences exploiting higher-order acoustic phenomena, and, concurrently, studies of the bioeffects of ultrasound under a range of imaging scenarios have been conducted. In 2012, the American Institute of Ultrasound in Medicine Technical Standards Committee convened a working group of its Output Standards Subcommittee to examine and report on the potential risks and benefits of the use of conditionally increased acoustic pressures (CIP) under specific diagnostic imaging scenarios. The term "conditionally" is included to indicate that CIP would be considered on a per-patient basis for the duration required to obtain the necessary diagnostic information. This document is a result of that effort. In summary, a fundamental assumption in the MI calculation is the presence of a preexisting gas body. For tissues not known to contain preexisting gas bodies, based on theoretical predications and experimentally reported cavitation thresholds, we find this assumption to be invalid. We thus conclude that exceeding the recommended maximum MI level given in the FDA guidance could be warranted without concern for increased risk of cavitation in these tissues. However, there is limited literature assessing the potential clinical benefit of exceeding the MI guidelines in these tissues. The report proposes a 3-tiered approach for CIP that follows the model for employing elevated output in magnetic resonance imaging and concludes with summary recommendations to facilitate Institutional Review Board (IRB)-monitored clinical studies investigating CIP in specific tissues.

Data analysis and review of radiology services at Glasgow 2014 Commonwealth Games.

Medical services at the Glasgow 2014 Commonwealth Games (CWG) were provided though a purpose-built medical polyclinic, which had a fully equipped radiology department along with other services, set up within the main Games Village. Data analysis of radiology services offered at CWG has not been published before. Imaging services within the polyclinic, Athletes Village, Glasgow 2014 CWG. The aim of the paper is to analyse data on radiological investigations and assess the demand and distribution of workload on imaging services at CWG 2014. Data on radiology investigations at the CWG 2014 was retrieved from the Carestream picture archiving and communication system (PACS) and Pharmasys (CWG official centralised electronic database system) and analysed. Six hundred ninety-seven diagnostic and interventional procedures were performed. Of these 37.9% were magnetic resonance imaging (MRI) scans, 22% were diagnostic ultrasound (US) examinations, 33.1% were radiographs, 4.3% were computed tomography (CT) scans and 2.7% were imaging-guided interventional procedures. 88% of imaging was performed on athletes and the remainder were performed on team officials and workforce. Demand on radiology services gradually picked up through the pre-competition period and peaked half way through the CWG. Radiology played a vital role in the successful provision of medical services at the Glasgow 2014 CWG. High demand on imaging services can be expected at major international sporting events and therefore pre-event planning is vital. Having back-up facilities in case of technical failure should be given due importance when planning radiology services at future CWG events.

Frequency of recommendations for additional imaging in diagnostic ultrasound examinations: Evaluation of radiologist, technologist, and other examination-related factors.

Our aim in this study was to evaluate the effect of the radiologist, technologist, and other examination-related factors on the frequency of recommendations for additional imaging (RAI) during sonographic (US) interpretation. We retrospectively reviewed 719 US reports from a single academic medical center for the presence of RAI. All studies had been interpreted by one of three abdominal radiologists. Examinations were performed at an outpatient radiology facility with no onsite radiologist (n = 299) or at an inpatient emergency department or hospital-based outpatient setting that had an onsite radiologist (n = 420). Possible associations between the frequency of RAI and the presence of an onsite radiologist, location of the examination, body part or region imaged, patient age, technologist performing the exam, and radiologist reading the exam were evaluated. There were significant differences between each pair of radiologists in terms of overall frequency of RAI (p < 0.001) (radiologist 1: 12.0% [22/184]; radiologist 2: 21.6% [78/361]; and radiologist 3: 45.5% [79/174]). In addition, there were statistically significant differences in the frequency of RAI among studies scanned by the 10 different US technologists (13.6%-40.0%, p = 0.03). However, other factors such as patient age, patient sex, US unit, patient location, and radiologist location were not associated with the frequency of RAI (p = 0.15-0.93). The individual radiologist and technologist influenced the frequency of RAI for US examinations, whereas other examination-related factors did not. The observed substantial variability in RAI between radiologists and technologists warrants further study, with consideration of strategies to optimize RAI within US reports.

Qualitative mammographic findings and outcomes of surveillance mammography after partial breast reconstruction with an autologous flap

This study describes the qualitative mammographic features after partial breast reconstruction with an autologous flap, and evaluates the diagnostic accuracy and recall rates of surveillance mammography after volume replacement in breast conserving surgery. Patients who had autologous partial breast reconstruction (N = 102) after breast-conserving surgery using either the myocutaneous latissimus dorsi mini-flap (N = 39) or fasciocutaneous chest wall perforator flap (N = 63) were reviewed. Mammograms done at one-year post surgery were analysed for characteristic qualitative features. All surveillance mammograms, diagnostic imaging and medical records were retrospectively reviewed. Mammograms of partially reconstructed breasts had distinctive features that correlated well with the surgical procedures. Median follow-up was 3 years, range 0-11 years. Of 295 surveillance mammograms, six (2%) resulted in a recall for further imaging and 3 (1%) proceeded to needle biopsy. Diagnostic imaging was performed for 13 (13/102, 12.7%) patients with symptoms, and only one (1/102, 1%) required a diagnostic biopsy. A conserved breast with an autologous flap within has characteristic mammographic features that differ from those after standard breast conserving surgery. Surveillance mammography after partial breast reconstruction is accurate, and recall/biopsy rates are low. Diagnostic breast ultrasound examination is effective evaluation for the symptomatic patient.

Primary avalvular varicose anomalies are a naturally occurring phenomenon that might be misdiagnosed as neovascular tissue in recurrent varicose veins.

The objective of this study was to report a phenomenon in patients with primary varicose veins that resembles neovascular tissue in postsurgical recurrences-primary avalvular varicose anomalies (PAVA). Between March 2012 and July 2013, 756 patients (122 men, 634 women) with primary varicose veins (mean age, 53years; range, 18-89years) underwent duplex ultrasonography with retrospective analysis of their reflux patterns. We diagnose PAVA as small, refluxing vessels in legs with primary varicose veins and no history of surgery, trauma, or infection in the area that show one or more of three patterns of distribution: lymph node pattern-PAVA arising directly from groin lymph nodes; peritruncal pattern-PAVA wrapping around the great, small, or anterior accessory saphenous veins; and atypical pattern. PAVA are predominantly found within the saphenous fascia, but components have been found to emerge into the superficial and deep venous compartments. We analyzed results from 1398 legs (756 patients). Sixty-four legs (4.6%) in 58 patients exhibited PAVA, bilateral in six patients and unilateral in 52 patients. Lymph node involvement and peritruncal PAVA were seen in 23.4% and 70.3% of legs, respectively. The small saphenous vein was the most common truncal vein to be involved (48.9% of peritruncal cases). More than one pattern of PAVA could be observed in seven legs. Of the 48 women with PAVA, 42% had concurrent pelvic vein reflux. Neovascularization has been identified as a major cause of clinically recurrent varicose veins. Neovascular tissue has been described after endovenous thermoablation. We suggest that this might represent PAVA undetected preoperatively in some cases. PAVA are thin-walled, serpiginous, incompetent vessels that resemble neovascular tissue. We conclude that neovascularization should be diagnosed as a source of recurrence after endovenous surgery only if PAVA had been actively looked for, and excluded, in the preoperative diagnostic duplex ultrasound examination.

Achilles tendon diagnostic ultrasound examination: A locally designed protocol and audit

AbstractBackgroundDiagnostic ultrasound is regarded as the gold standard for imaging tendinopathies for diagnosis, focusing rehabilitation, and guided intervention. However, there are no published diagnostic ultrasound protocols for the Achilles tendon which represent best practice. In the Felixstowe Community Hospital Physiotherapy Department a protocol for diagnostic ultrasound examination of the Achilles tendon was implemented in January 2013 and acts as a local guideline.ObjectivesTo determine whether a local Achilles tendon image protocol is being adhered to in diagnostic ultrasound examinations of mid-portion Achilles tendinopathy. A pre-determined 75% adherence to the protocol was set as the standard representing best practice in diagnostic ultrasound examination of the Achilles tendon. A target of 100% of diagnostic ultrasound examinations should meet this standard.MethodsData collection of acquired and archived diagnostic ultrasound examinations with a subsequent diagnosis of mid-portion Achilles...

Imaging at London 2012 summer Olympic Games: analysis of demand and distribution of workload

BackgroundVery little data on the provision of imaging services at the summer Olympic Games have been published before. With 7.9 million Euros (£6.6 million, US$11 million) invested into setting up...

Anatomical evaluation of the organs in the red swamp crayfish, Procambarus clarkii, by diagnostic ultrasound examination

We describe the ultrasound examination of the cephalothorax and pleon in red swamp crayfish. Real-time B-mode, Color and Power Doppler examinations were performed on 10 crayfish, Procambarus clarkii (Girard, 1852). We envisage that use of this technique will provide baseline information for further imaging studies to investigate the cardiovascular and digestive physiology and can be applied to identify disorders in crayfish, to say nothing of use in other crustaceans.

Theoretical Modelling of Alveolar Resonance Mechanism of Ultrasound-Induced Lung Haemorrhage

The possibility of the ultrasound-induced lung haemorrhage occurring in adult human during diagnostic ultrasound examination is studied here. This study is based on the hypothetical alveolar resonance mechanism of the ultrasound-induced lung haemorrhage. The alveolar wall is initially modelled here as a square membrane with fixed-boundary, and then theoretically subjected to vibration analysis. The equation of threshold pressure for the occurrence of ultrasound-induced lung haemorrhage is derived. A comparison test against past experimental data validates the use of the square membrane model of the alveolar wall in studying the ultrasound induced lung haemorrhage. This study predicts that the ultrasound-induced lung haemorrhage in adult human can be prevented if the ultrasound frequency is kept above 1.69 MHz while the Mechanical Index does not exceed 1.9.

Time to Return to Play After High Ankle Sprains in Collegiate Football Players

Background:Determining the severity of high ankle sprains in athletes and predicting the time that an athlete can return to unrestricted sport activities following this injury remain significant challenges.Purpose:The objectives of this study were (1) to determine if objective measurements of injury severity after high ankle sprains could predict the time to return to play in Division I football players and (2) to determine whether physical examination or diagnostic musculoskeletal ultrasound was more predictive of return to play. The hypothesis was that objective measures of injury severity of a high ankle sprain can be predictive of time to return to athletic participation in collegiate football players.Study Design:Prospective case series.Methods:Twenty consecutive Division I collegiate football players with a diagnosis of a grade I high ankle sprain (syndesmosis sprain without diastasis) were studied. Two clinical measurements of injury severity were determined: the height of the zone of injury on physical examination and the height of the zone of injury as defined by diagnostic musculoskeletal ultrasound examination. All athletes followed a standardized treatment program and return-to-play criteria. A regression model and Cox proportional hazards model were developed to determine time to return to unrestricted play as a function of injury severity and player position.Results:Physical examination but not ultrasound was significantly correlated with time to return to play. Regression and Cox analyses revealed that injury severity on physical examination and player position were significant predictors of time to return to unrestricted play following high ankle sprain.Conclusions:Injury severity on physical examination and player position are associated with the time to return to unrestricted athletic activity after injury. A model based on the data can be applied to help predict the time to return to unrestricted play in Division I collegiate football players following high ankle sprain.

The Information Imperative: Is It Time for an Informed Consent Process Explaining the Risks of Medical Radiation?

We believe that the radiology community should take the initiative to adopt guidelines and require that all imaging facilities use some form of active information process describing the risks of medical radiation.

Subcentimeter Thyroid Nodules: Utility of Sonographic Characterization and Ultrasound-Guided Needle Biopsy

The purpose of this study is to examine subcentimeter thyroid nodules to determine their rate of malignancy, the accuracy of various ultrasound features in prediction of malignancy, and the utility of ultrasound-guided biopsy of these nodules. Included in this retrospective study were 104 patients in whom 108 thyroid nodules smaller than 1 cm had been biopsied. Diagnostic ultrasound examinations were reviewed, and nodules were evaluated for the following ultrasound features: internal echogenicity, margins, height-to-width ratio, presence of calcifications, posterior acoustic features, solid-to-cystic ratio, presence of a halo, and color Doppler characteristics. In addition, a subjective assessment of level of suspicion was assigned to each nodule. Each feature was correlated with the pathologic results to determine the accuracy of the feature for predicting malignancy. Adequate cytologic specimens were obtained in 97 of the 108 subcentimeter biopsies (90%) performed. The average size of malignant nodules was significantly smaller than the average size of benign nodules (6.4 ± 2.1 vs 7.7 ± 1.4 mm, p = 0.041). The rate of carcinoma among nodules with a final diagnosis was 19% (16/85). The most accurate features significantly associated with malignancy were posterior acoustic shadowing (87%), many diffuse calcifications (82%), rim calcifications (81%), and taller than wide shape (79%). The subjective level of suspicion correlated well with the presence of malignancy (76%). Subcentimeter nodules are significantly associated with the risk of malignancy and can be accurately and safely biopsied with a very high diagnostic rate. Certain ultrasound features can be used to accurately stratify risk of malignancy, although no single feature replaces the clinician's overall impression.