Paul M. Bunch

Dual-Energy CT of Incidental Findings in the Abdomen: Can We Reduce the Need for Follow-Up Imaging?

OBJECTIVE The purpose of this article is to review the added value of dual-energy CT for characterization of incidental lesions discovered during routine abdominal CT. CONCLUSION Dual-energy CT allows acquisition of virtual unenhanced images, iodine maps, and virtual monochromatic images, all of which can aid in characterizing incidental lesions at the time of detection. Virtual unenhanced images and iodine maps are used for assessment of enhancement of incidental lesions, which can help differentiate suspicious enhancing lesions from benign nonenhancing lesions. Virtual monochromatic images can be obtained at low energy to improve conspicuity and detection of subtle lesions. Routine use of dual-energy CT may eliminate the need for additional imaging in the workup of some of these incidental lesions.

A biomechanical approach to distal radius fractures for the emergency radiologist.

Distal radius fractures are the most common upper extremity fracture and account for approximately one sixth of all fractures treated in US emergency departments. These fractures are associated with significant morbidity and have a major economic impact. Radiographic evaluation of distal radius fractures is frequently performed in the emergency department setting, has a profound impact on initial management, and is essential to assessing the quality and relative success of the initial reduction. While the most appropriate definitive management of distal radius fractures remains controversial, overarching treatment principles reflect distal radius injury mechanisms and biomechanics. An intuitive understanding of the biomechanics of the distal radius and of common mechanisms of injury informs and improves the emergency radiologist’s ability to identify key imaging findings with important management implications and to communicate the critical information that emergency physicians and orthopedic surgeons need to best manage distal radius fractures.

Anatomic Eponyms in Neuroradiology: Brain, Cerebral Vasculature, and Calvarium

Medical eponyms are ubiquitous, numerous, and at times controversial. They are often useful for succinctly conveying complex concepts, and familiarity with eponyms is important for proper usage and appropriate communication. In this historical review, we identify 18 anatomic eponyms used to describe structures of the brain, cerebral vasculature, and calvarium. For each structure, we first offer a biographical sketch of the individual for whom the structure is named. This is followed by a description of the anatomic structure and a brief discussion of its clinical relevance.

Skeletal development of the hand and wrist: digital bone age companion—a suitable alternative to the Greulich and Pyle atlas for bone age assessment?

PurposeTo assess reader performance and subjective workflow experience when reporting bone age studies with a digital bone age reference as compared to the Greulich and Pyle atlas (G&P). We hypothesized that pediatric radiologists would achieve equivalent results with each method while digital workflow would improve speed, experience, and reporting quality.Materials and methodsIRB approval was obtained for this HIPAA-compliant study. Two pediatric radiologists performed research interpretations of bone age studies randomized to either the digital (Digital Bone Age Companion, Oxford University Press) or G&P method, generating reports to mimic clinical workflow. Bone age standard selection, interpretation-reporting time, and user preferences were recorded. Reports were reviewed for typographical or speech recognition errors. Comparisons of agreement were conducted by way of Fisher’s exact tests. Interpretation-reporting times were analyzed on the natural logarithmic scale via a linear mixed model and transformed to the geometric mean. Subjective workflow experience was compared with an exact binomial test. Report errors were compared via a paired random permutation test.ResultsThere was no difference in bone age determination between atlases (p = 0.495). The interpretation-reporting time (p < 0.001) was significantly faster with the digital method. The faculty indicated preference for the digital atlas (p < 0.001). Signed reports had fewer errors with the digital atlas (p < 0.001).ConclusionsBone age study interpretations performed with the digital method were similar to those performed with the Greulich and Pyle atlas. The digital atlas saved time, improved workflow experience, and reduced reporting errors relative to the Greulich and Pyle atlas when integrated into electronic workflow.

Trochlear Groove and Trochlear Cistern: Useful Anatomic Landmarks for Identifying the Tentorial Segment of Cranial Nerve IV on MRI

BACKGROUND AND PURPOSE: The trochlear groove and trochlear cistern are anatomic landmarks closely associated with the tentorial segment of cranial nerve IV. The purposes of this study were to describe the MR imaging appearances of the trochlear groove and trochlear cistern and to test our hypothesis that knowledge of these anatomic landmarks facilitates identification of cranial nerve IV in routine clinical practice. MATERIALS AND METHODS: For this retrospective study, consecutive MR imaging examinations of the sinuses performed in 25 patients (50 sides) at our institution were reviewed. Patient characteristics and study indications were recorded. Three readers performed independent assessments of trochlear groove, cistern, and nerve visibility on coronal images obtained by using a T2-weighted driven equilibrium radiofrequency reset pulse sequence. RESULTS: Interobserver agreement was 78% for visibility of the trochlear groove, 56% for the trochlear cistern, and 68% for cranial nerve IV. Following consensus review, the trochlear groove was present in 44/50 sides (88%), the trochlear cistern was present in 25/50 sides (50%), and cranial nerve IV was identified in 36/50 sides (72%). When the trochlear groove was present, cranial nerve IV was identified in 35/44 sides (80%), in contrast to 1/6 sides (17%) with no groove (P = .0013). When the trochlear cistern was present, cranial nerve IV was identified in 23/25 sides (92%), in contrast to 13/25 sides (52%) with no cistern (P = .0016). CONCLUSIONS: The trochlear groove and trochlear cistern are anatomic landmarks that facilitate identification of cranial nerve IV in routine clinical practice.

Anatomic Eponyms in Neuroradiology: Head and Neck

In medicine, an eponym is a word-typically referring to an anatomic structure, disease, or syndrome-that is derived from a persons name. Medical eponyms are ubiquitous and numerous. They are also at times controversial. Eponyms reflect medicines rich and colorful history and can be useful for concisely conveying complex concepts. Familiarity with eponyms facilitates correct usage and accurate communication. In this article, 22 eponyms used to describe anatomic structures of the head and neck are discussed. For each structure, the author first provides a biographical account of the individual for whom the structure is named. An anatomic description and brief discussion of the structures clinical relevance follow.

Intraprocedural Ablation Margin Assessment by Using Ammonia Perfusion PET during FDG PET/CT–guided Liver Tumor Ablation: A Pilot Study

Purpose To prospectively determine whether nitrogen 13 (13N) ammonia perfusion positron emission tomography (PET) during fluorine 18 fluorodeoxyglucose (FDG) PET/computed tomography (CT)-guided liver tumor ablation can be used to intraprocedurally assess ablation margins. Materials and Methods Eight patients (five women and three men; age range, 36-74 years; mean age, 57 years) were enrolled in this pilot study and underwent FDG PET/CT-guided microwave ablation of 11 FDG-avid liver metastases (mean diameter, 22 mm; range, 11-34 mm). All procedures were performed between March 2014 and December 2016. Complete ablation margin visibility and minimum ablation margin thickness were assessed by using intraprocedural 13N-ammonia perfusion PET compared with 24-hour postprocedural MR imaging by two independent blinded radiologists. Local tumor progression for each ablated tumor was assessed at follow-up imaging for 3-38 months (median, 17.6 months). Descriptive analysis was performed. Results Eleven of 11 (100%) ablation margins were fully assessable by using intraprocedural perfusion PET by both readers; six of eleven (55%) margins were fully assessable by both readers at postprocedural 24-hour MR imaging. By using perfusion PET, one tumor that had been judged by both readers to have a minimum margin of 0 mm progressed locally. No tumors judged to have a minimum margin greater than 0 mm at perfusion PET progressed locally. Conclusion 13N-ammonia perfusion PET during FDG PET/CT-guided liver tumor ablations can potentially be used to intraprocedurally assess the entire ablation margin, including the minimum margin.

Preoperative Imaging Techniques in Primary Hyperparathyroidism: A Review

Importance Successful minimally invasive parathyroidectomy requires confident and accurate preoperative localization. Several noninvasive imaging techniques are well established for preoperative localization, and others are emerging. Observations Ultrasonography and sestamibi imaging are established preoperative localization techniques with good sensitivity and positive predictive value. Multiphase 4-dimensional computed tomography is a newer technique with arguably superior performance, particularly in the setting of negative or discordant ultrasonography and sestamibi imaging, residual or recurrent primary hyperparathyroidism following a previous surgical operation, and multiglandular disease. Emerging techniques that may further facilitate confident and accurate preoperative localization include ultrasonography, elastography, positron emission tomography, and 4-D magnetic resonance imaging. Conclusions and Relevance The optimal imaging localization algorithm for hyperparathyroidism remains undetermined, but a combination of techniques tailored to the specific scenario will likely yield the best outcomes. An algorithm is proposed that considers test performance, surgeon confidence, patient-specific factors, cost, local radiologic expertise, and patient radiation exposure.