High-pitch versus standard mode CT pulmonary angiography: a comparison of indeterminate studies.

PURPOSE: To compare the causes of indeterminate CT pulmonary angiograms using standard mode and high-pitch mode, and determine at what level of the pulmonary arterial tree studies were non-diagnostic. METHODS: IRB approval was obtained. A retrospective review of patients at our institution who underwent a CT pulmonary angiogram, between November 1, 2015 and February 10, 2016 was performed. CT pulmonary angiograms using both high-pitch mode and standard mode were evaluated with positive and indeterminate rates calculated. Causes of indeterminate studies and the level of the pulmonary arterial tree at which the study became non-diagnostic were determined by a board certified radiologist by looking at the images of each indeterminate study. The indeterminate rates were compared between high-pitch and standard modes using a generalized estimating equation. RESULTS: Five hundred fifty-nine CT pulmonary angiograms using high-pitch mode were evaluated, while 661 standard mode scans were evaluated. 69/559 (12.3%) scans with high-pitch mode were positive and 84/661 (12.7%) scans with standard mode were positive (not statistically significant, p > 0.05). There was a higher rate of indeterminate scans with standard mode compared to the high-pitch mode (80 [12.1%] standard vs. 25 [4.5%] high-pitch, p value < 0.0001). Findings were indeterminate at the lobar level in 4 (16%), at the segmental level in 11 (44%), and at the subsegmental level in 10 (40%) using high-pitch mode. The most common causes of an indeterminate scan using high-pitch mode were motion in 11 (44%), transient interruption of contrast in 6 (24%), and contrast timing in 5 (20%). Findings were indeterminate at the main pulmonary artery level in 1 (1.3%), at the lobar level in 13 (16.3%), at the segmental level in 28 (35.0%), and at the subsegmental level in 38 (47.5%) using the standard mode. The most common causes of an indeterminate scan using the standard mode were motion in 53 (66.3%), transient interruption of contrast in 19 (23.8%), and contrast timing in 15 (18.8%). CONCLUSIONS: High-pitch mode results in statistically significant fewer indeterminate studies compared with standard mode. Furthermore, there were statistically significant fewer indeterminate studies due to motion artifact with high-pitch mode compared with standard mode.

Safety and Outcomes of Percutaneous Biopsy of 61 Hepatic Adenomas.

OBJECTIVE: Given the recent classification of hepatic adenoma (HA) into subtypes and recognition of imperfect specificity of MRI to differentiate HA from focal nodular hyperplasia (FNH), there is a resurgent interest in the role of biopsy to diagnose HA. The purpose of this study was to determine the safety and outcomes of biopsy of HAs. MATERIALS AND METHODS: A retrospective review of the electronic medical records of all patients who underwent hepatic mass biopsy revealing HA from 2000 through 2013 was performed. The biopsy procedure parameters were evaluated. Complications were graded using the Common Terminology Criteria for Adverse Events. Pathology-specific outcomes related to the diagnosis of HA were assessed. RESULTS: Sixty patients (52 women and eight men) were identified with a mean age of 42 ± 13 (SD) years and a mean follow-up of 2.3 ± 3.0 years after biopsy. One patient had two HAs biopsied during the same procedure, resulting in a total of 61 biopsy-proven HAs. Of the 60 patients, one patient (2%) had a single major complication, which involved bleeding that resulted in a blood transfusion, and six patients (10%) had a minor complication. A total of six (10%) discordant biopsy results were found: Four biopsy-proven HAs (7%) revealed FNH on surgical resection or repeat biopsy, one HA (2%) showed well-differentiated hepatocellular carcinoma (HCC) at subsequent biopsy, and one HA (2%) showed findings suggestive of HCC on follow-up imaging. CONCLUSION: Complications after biopsy of HAs are uncommon. Although uncommon, discordant pathology results between biopsy and surgical resection may occur.

CNS imaging findings associated with Parry-Romberg syndrome and en coup de sabre: correlation to dermatologic and neurologic abnormalities.

INTRODUCTION: Parry-Romberg syndrome (PRS) and en coup de sabre (ECS) are variants of morphea. Although numerous findings on central nervous system (CNS) imaging of PRS and ECS have been reported, the spectrum and frequency of CNS imaging findings and relation to cutaneous and neurologic abnormalities have not been fully characterized. METHODS: We retrospectively reviewed patients younger than 50 years at our institution over a 16-year interval who had clinical diagnosis of PRS and ECS by a skin or facial subspecialist. Two neuroradiologists evaluated available imaging and characterized CNS imaging findings. RESULTS: Eighty-eight patients with PRS or ECS were identified (62 women [70.4 %]; mean age 28.8 years). Of the 43 patients with CNS imaging, 19 (44 %) had abnormal findings. The only finding in 1 of these 19 patients was lateral ventricle asymmetry; of the other 18, findings were bilateral in 11 (61 %), ipsilateral to the side of facial involvement in 6 (33 %), and contralateral in 1 (6 %). Sixteen patients had serial imaging examinations over an average of 632 days; 13 (81 %) had stable imaging findings, and 3 (19 %) had change over time. Of six patients with progressive cutaneous findings, five (83 %) had stable imaging findings over time. Among the 23 patients with clinical neurologic abnormality and imaging, 12 (52 %) had abnormal imaging findings. All seven patients with seizures (100 %) had abnormal imaging studies. CONCLUSIONS: In PRS and ECS, imaging findings often are bilateral and often do not progress, regardless of cutaneous disease activity. Findings are inconsistently associated with clinical abnormalities.

How common is fatty infiltration of the teres minor in patients with shoulder pain? A review of 7,367 consecutive MRI scans.

PURPOSE: The teres minor is particularly important for activities that require external rotation in abduction in the settings of both rotator cuff tears and reverse shoulder arthroplasty. This study sought to assess the incidence of teres minor fatty infiltration in a large cohort of consecutive patients evaluated with shoulder MRI for shoulder pain and to identify all associated pathologies in an effort to determine the various potential etiologies of teres minor involvement. METHODS: A retrospective review of 7,376 non-contrast shoulder MRI studies performed between 2010 and 2015 were specifically evaluated for teres minor fatty infiltration. Studies were reviewed by two fellowship trained musculoskeletal radiologists. Muscle atrophy was graded on a 3-point scale according to Fuchs and Gerber. The remaining rotator cuff tendons and muscles, biceps tendon, labrum, and joint surfaces were assessed on MRI as well. RESULTS: In this series, 209 (2.8%) shoulders were noted to have fatty infiltration of the teres minor. The rate of isolated fatty infiltration of the teres minor was 0.4%. Concomitant deltoid muscle atrophy was common, and occurred in 68% of the shoulders with fatty infiltration of the teres minor. Tearing of the teres minor tendon was extremely rare. CONCLUSION: Fatty infiltration of the teres minor can occur in isolation, be associated with deltoid muscle atrophy only, or occur in the setting of rotator cuff full tears. Thus, fatty infiltration of the teres minor may be related to a neurologic process or disuse. Further long term longitudinal studies are necessary to be elucidate the etiologies. LEVEL OF EVIDENCE: Level IV.

CT-derived sarcopenia should not preclude surgical stabilization of traumatic rib fractures.

BACKGROUND: Rib fractures are associated with considerable morbidity and mortality. Surgical stabilization of rib fractures (SSRF) can be performed to mitigate complications. Sarcopenia is in general known to be associated with poor clinical outcomes. We investigated if sarcopenia impacted number of days of mechanical ventilation, intensive care unit (ICU) stay, and total hospital stay in patients who underwent SSRF. METHODS: A retrospective single institutional review was performed including patients who underwent SSRF (2009-2017). Skeletal muscle index (SMI) was semiautomatically calculated at the L3 spinal level on computed tomography (CT) images and normalized by patient height. Sarcopenia was defined as SMI < 55 cm2/m2 in males and < 39 cm2/m2 in females. Demographics, operative details, and postoperative outcomes were reviewed. Univariate and multivariate analyses were performed. RESULTS: Of 238 patients, 88 (36.9%) had sarcopenia. There was no significant difference in number of days of mechanical ventilation (2.8 ± 4.9 versus 3.1 ± 4.3, p = 0.304), ICU stay (5.9 ± 6.5 versus 4.9 ± 5.7 days, p = 0.146), or total hospital stay (13.3 ± 7.2 versus 12.9 ± 8.2 days, p = 0.183) between sarcopenic and nonsarcopenic patients. Sarcopenic patients demonstrated increased modified frailty index scores (1.5 ± 1.1 versus 0.9 ± 0.9, p < 0.001) compared to nonsarcopenic patients. CONCLUSIONS: For patients who underwent SSRF for rib fractures, sarcopenia did not increase the number of days of mechanical ventilation, ICU stay, or total hospital stay. Sarcopenia should not preclude the utilization of SSRF in these patients.

Structured Head and Neck CT Angiography Reporting Reduces Resident Revision Rates.

PURPOSE: This resident-driven quality improvement project was undertaken to assess the effectiveness of structured reporting to reduce revision rates for afterhours reports dictated by residents. METHODS: The first part of the study assessed baseline revision rates for head and neck CT angiography (CTA) examinations dictated by residents during afterhours call. A structured report was subsequently created based on templates on the RSNA informatics reporting website and critical findings that should be assessed for on all CTA examinations. The template was made available to residents through the speech recognition software for all head and neck CTA examinations for a duration of 2 months. Report revision rates were then compared with and without use of the structured template. RESULTS: The structured template was found to reduce revision rates by approximately 50% with 10/41 unstructured reports revised and 2/17 structured reports revised. CONCLUSIONS: We believe that structured reporting can help reduce reporting errors, particularly in term of typographical errors, train residents to evaluate complex examinations in a systematic fashion, and assist them in recalling critical findings on these examinations.

Spinal cord infarction: Clinical and imaging insights from the periprocedural setting.

OBJECTIVE: Describe the range of procedures associated with spinal cord infarction (SCI) as a complication of a medical/surgical procedure and define clinical and imaging characteristics that could be applied to help diagnose spontaneous SCI, where the diagnosis is often less secure. METHODS: We used an institution-based search tool to identify patients evaluated at Mayo Clinic, Rochester, MN from 1997 to 2016 with a periprocedural SCI. We performed a descriptive analysis of clinical features, MRI and other laboratory findings, and outcome. RESULTS: Seventy-five patients were identified with SCI related to an invasive or non-invasive surgery including: aortic aneurysm repair (49%); other aortic surgery (15%); and a variety of other procedures (e.g., cardiac surgery, spinal decompression, epidural injection, angiography, nerve block, embolization, other vascular surgery, thoracic surgery) (36%). Deficits were severe (66% para/quadriplegia) and maximal at first post-procedural evaluation in 61 patients (81%). Impaired dorsal column function was common on initial examination. Imaging features included classic findings of owl eyes or anterior pencil sign on MRI (70%), but several other T2-hyperintensity patterns were also seen. Gadolinium enhancement of the SCI and/or cauda equina was also common when assessed. Six patients (10%) had an initial normal MRI despite a severe deficit. CONCLUSIONS: Procedures associated with SCI are many, and this complication does not exclusively occur following aortic surgery. The clinical and radiologic findings that we describe with periprocedural SCI may be used in future studies to help distinguish spontaneous SCI from alternate causes of acute myelopathy.

Quadrilateral space syndrome: the Mayo Clinic experience with a new classification system and case series.

Quadrilateral space syndrome (QSS) arises from compression or mechanical injury to the axillary nerve or the posterior circumflex humeral artery (PCHA) as they pass through the quadrilateral space (QS). Quadrilateral space syndrome is an uncommon cause of paresthesia and an underdiagnosed cause of digital ischemia in overhead athletes. Quadrilateral space syndrome can present with neurogenic symptoms (pain and weakness) secondary to axillary nerve compression. In addition, repeated abduction and external rotation of the arm is felt to lead to injury of the PCHA within the QSS. This often results in PCHA thrombosis and aneurysm formation, with distal emboli. Because of relative infrequency, QSS is rarely diagnosed on evaluation of athletes with such symptoms. We report on 9 patients who presented at Mayo Clinic with QSS. Differential diagnosis, a new classification system, and the management of QSS are discussed, with a comprehensive literature review. The following search terms were used on PubMed: axillary nerve, posterior circumflex humeral artery, quadrilateral space, and quadrangular space. Articles were selected if they described patients with symptoms from axillary nerve entrapment or PCHA thrombosis, or if related screening or imaging methods were assessed. References available within the obtained articles were also pursued. There was no date or language restriction for article inclusion; 5 studies in languages besides English were reported in German, French, Spanish, Turkish, and Chinese.