MRI T2 mapping assessment of T2 relaxation time in desmoid tumors as a quantitative imaging biomarker of tumor response: preliminary results

Objectives

Because size-based imaging criteria poorly capture biologic response in desmoid-type fibromatosis (DF), changes in MRI T2 signal intensity are frequently used as a response surrogate, but remain qualitative. We hypothesized that absolute quantification of DF T2 relaxation time derived from parametric T2 maps would be a feasible and effective imaging biomarker of disease activity.

Methods

This IRB-approved retrospective study included 11 patients with DF, managed by observation or systemic therapy, assessed by 3T MRI. Tumor maximum diameter, volume, and T2-weighted signal intensity were derived from manual tumor segmentations. Tumor:muscle T2 signal ratios were recorded. Two readers measured tumor T2 relaxation times using a commercial T2 scanning sequence, manual ROI delineation and commercial calculation software enabling estimation of reader reliability. Objective response rates based on RECIST1.1 and best responses were compared between size-based and signal-based parameters.

Results

Median patient age was 52.6 years; 8 subjects were female (73%). Nine patients with longitudinal assessments were followed for an average of 314 days. Median baseline tumor diameter was 7.2 cm (range 4.4 - 18.2 cm). Median baseline T2 was 65.1 ms (range 40.4 - 94.8 ms, n=11); median at last follow-up was 44.3 ms (-32% from baseline; range 29.3 - 94.7 ms, n=9). T2 relaxation times correlated with tumor:muscle T2 signal ratios, Spearman p=0.78 (p<0.001). T2 mapping showed high inter-reader reliability, ICC=0.84. The best response as a percentage change in T2 values was statistically significant (mean -17.9%, p=0.05, paired t-test) while change in diameter was not (mean -8.9%, p=0.12).

Conclusions

Analysis of T2 relaxation time maps of DF may offer a feasible quantitative biomarker for assessing the extent of response to treatment. This approach may have high inter-reader reliability.

Hand and finger, ultrasound-guided, percutaneous core needle biopsies: A safe procedure with high diagnostic accuracy

Introduction/Purpose

To determine the diagnostic accuracy and complication rates of ultrasound-guided, percutaneous core needle biopsies of soft tissue masses in the hand and fingers.

Methods

Reports from all ultrasound-guided procedures between 21 May 2014 and 17 March 2022 were queried for keywords including "hand", OR "finger", AND "biopsy". Patient demographics, lesion size and location, biopsy needle gauge and the number of cores obtained were recorded. The final pathology of the mass excision was then compared with the core needle biopsy (CNB) for each patient.

Results

Sixty-six records were reviewed, and 37 patients met inclusion criteria. Maximum lesion diameter averaged 1.45 cm with a range between 0.4 and 4.3 cm. The frequency of needle gauges used was 14G (14%), 16G (24%), 18G (38%), 20G (11%) and 'not reported' (14%). The mean number of tissue cores obtained was 2.9 (SD 1.2; range 1 to 6), excluding nine cases that reported 'multiple'. The frequency of CNB diagnoses included tenosynovial giant cell tumour (TGCT) at 30%, ganglion cyst at 11% and epidermal inclusion cyst at 5%. CNB was 100% sensitive in detecting the three (8%) malignancies. Of the 37 tumours biopsied, 16 were surgically excised. One angiomyoma was originally diagnosed as a haemangioma on CNB, but all other histologic results were concordant for a diagnostic accuracy of 97%.

Discussion

Small soft tissue masses in the hands and fingers, even those less than 1 cm, are often amenable to ultrasound-guided CNB. Performance under image guidance facilitates retrieval of core specimens adquate for histologic diagnosis with relatively few passes using higher gauge needles.

Conclusion

Overall, ultrasound-guided CNB of the hand and fingers is safe and highly accurate in diagnosing soft tissue tumours. The accuracy is unrelated to the needle's gauge, the number of passes and the size of the lesions.

PET-CT in the Evaluation of Neoadjuvant/Adjuvant Treatment Response of Soft-tissue Sarcomas: A Comprehensive Review of the Literature

➢

In soft-tissue sarcomas (STSs), the use of positron emission tomography-computed tomography (PET-CT) through a standardized uptake value reduction rate correlates well with histopathological response to neoadjuvant treatment and survival.

➢

PET-CT has shown a better sensitivity to diagnose systemic involvement compared with magnetic resonance imaging and CT; therefore, it has an important role in detecting recurrent systemic disease. However, delaying the use of PET-CT scan, to differentiate tumor recurrence from benign fluorodeoxyglucose uptake changes after surgical treatment and radiotherapy, is essential.

➢

PET-CT limitations such as difficult differentiation between benign inflammatory and malignant processes, inefficient discrimination between benign soft-tissue tumors and STSs, and low sensitivity when evaluating small pulmonary metastases must be of special consideration.

Systemic Chemotherapies Retain Antitumor Activity in Desmoid Tumors Independent of Specific Mutations in CTNNB1 or APC: A Multi-institutional Retrospective Study

PURPOSE

Determine whether specific CTNNB1 or APC mutations in patients with desmoid tumor were associated with differences in clinical responses to systemic treatments.

EXPERIMENTAL DESIGN

We established a multi-institutional dataset of previously treated patients with desmoid tumor across four U.S. sarcoma centers, including demographic and clinicopathologic characteristics, treatment regimens, and clinical and radiographic responses. CTNNB1 or APC mutation status was determined from prior pathology records, or archival tissue was requested and analyzed by Sanger sequencing and/or next-generation sequencing. Evaluable patients with mutation results were analyzed to determine clinical progression-free survival (cPFS), RECIST 1.1 PFS (rPFS), time to next treatment (TTNT), and overall survival (OS). Kaplan-Meier analysis and Cox proportional hazards regression were performed to identify differences in cPFS, rPFS, TTNT, and OS by mutation subtype, desmoid tumor location, and treatment regimen.

RESULTS

A total of 259 evaluable patients were analyzed for at least one of the survival outcomes, with 177 patients having mutation data. First- and second-line cPFS, rPFS, and TTNT were not significantly affected by mutation subtype; however, APC-mutant desmoid tumors demonstrated nonstatistically significant inferior outcomes. Extremity/trunk desmoid tumor location and treatment with doxorubicin-based, methotrexate/vinca alkaloids and sorafenib regimens were associated with better clinical outcomes compared with surgery or "other" therapies, including estrogen-receptor blockade and imatinib. OS was significantly worse with APC or CTNNB1 negative/other mutations.

CONCLUSIONS

Mutation subtype did not affect responses to specific systemic therapies. APC mutations and nonextremity desmoid tumor locations remain prognostic for worse outcomes, and earlier initiation of systemic therapy for these higher-risk desmoid tumors should be prospectively evaluated. See related commentary by Greene and Van Tine, p. 3911.

Radiographic Evaluation of Elbow Fractures

Fractures and dislocations of the elbow are a common cause of emergency department visits each year. Radiography remains the bedrock of an initial injury assessment, and recognition of distinctive injury patterns based on fracture location, morphology, and severity, guides optimal clinical decision-making. This article reviews basic elbow anatomy, frequently seen fractures and injury patterns, and highlights how these findings influence surgical planning and patient management.

Differential diagnosis of T2 hypointense masses in musculoskeletal MRI

Many soft tissue masses have an indeterminate appearance on MRI, often displaying varying degrees and extent of T2 hyperintensity. However, a subset of neoplasms and tumor-like lesions may exhibit prominent areas of T2 hypointensity relative to skeletal muscle. The hypointensity observed on T2-weighted MRI can be caused by a variety of substances, including evolving blood products, calcifications or other inorganic crystals, or fibrous tissue. Carefully evaluating the presence and pattern of T2 hypointensity in soft tissue masses and considering potential causes in their associated clinical contexts can help to narrow the differential diagnosis among neoplastic and non-neoplastic possibilities. These include endometriosis, aneurysmal bone cysts, tenosynovial giant cell tumor, arteriovenous malformation and pseudoaneurysm, calcium pyrophosphate and hydroxyapatite deposition diseases, tumoral calcinosis, gout, amyloidosis, hemangiomas with phleboliths, low-grade fibromyxoid sarcoma, ossifying fibromyxoid tumor, collagenous fibroma, desmoid-type fibromatosis, myxofibrosarcoma, peripheral nerve sheath tumors, dedifferentiated liposarcoma, and treated sarcoma.

Septic Arthritis of the Shoulder After SARS-CoV-2 Pfizer Vaccination: A Case Report

CASE

We report a case of a 68-year-old woman who developed left shoulder glenohumeral joint septic arthritis within 1 week of receiving the COVID-19 Pfizer-BioNTech vaccine.

CONCLUSION

Common vaccine complications include injection site pain, fever, chills, arthralgia, and hypersensitivity reactions. A less common and more serious complication of septic arthritis has been reported and requires invasive treatment of surgical irrigation and debridement, and culture-specific parenteral antibiotic therapy. The current report highlights the clinical presentation and significant potential for serious complication with the improper technique. We urge vaccine administrators to practice caution and aseptic technique when vaccinating patients to reduce the risk of complication and morbidity.

MRI Volumetrics and Image Texture Analysis in Assessing Systemic Treatment Response in Extra-Abdominal Desmoid Fibromatosis

Purpose To determine whether MRI volumetric and image texture analysis correlates with treatment-induced biologic changes in desmoid fibromatosis (DF) earlier than conventional response criteria. Materials and Methods This retrospective study included 27 patients with histologically proven extra-abdominal DF who were managed with active surveillance or systemic therapy (from 2004 to 2016). MRI volumetric and image texture parameters were derived from manual tumor segmentations, and tumor signal intensity was normalized to muscle. Results were compared with objective response rates based on Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1, World Health Organization (WHO) lesion response, volumetrics, and MRI-modified Choi criteria. Correlation coefficients (r) between image texture features and maximum tumor diameters were obtained by using a meta-analysis approach. Results The 27 included patients (mean age, 39 years; 74% women) were followed for an average of 4 years, comprising 207 distinct time-point assessments. The mean baseline tumor maximum diameter was 7.9 cm (range, 3.4-15.2 cm). Partial response (PR) rates as best response were 37%, 44%, 70%, and 81% by RECIST, WHO, volumetrics, and MRI-modified Choi criteria, respectively. Among the 10 tumors showing RECIST PR, a preceding MRI-modified Choi PR was observed in 70% (seven of 10), on average 1.3 years earlier. Multiple image texture parameters showed associations with objective measurements of tumor diameter including mean tumor-to-muscle signal ratio (r = 0.51; P = .004), median tumor-to-muscle signal ratio (r = 0.52; P = .003), energy (r = 0.48; P < .001), run entropy (r = 0.32, P = .04), and gray-level nonuniformity (r = 0.54; P ≤ .001). Conclusion Volumetric signal and image texture assessment allows more comprehensive analysis of DF biologic change and may permit early prediction of DF behavior and therapeutic response. Keywords: MR Imaging, Soft Tissues/Skin, Neoplasms-Primary © RSNA, 2021.

Superficial fibromatosis: MRI radiomics and T2 mapping correlate with treatment response

BACKGROUND

Superficial fibromatosis exhibits variable MR signal intensity due to collagenous and fibroproliferative components. Quantifying this signal heterogeneity using image texture analysis and T2-mapping could have prognostic and therapeutic implications.

METHODS

This IRB-approved retrospective study included 13 patients with superficial fibromatosis, managed by observation, electron beam radiotherapy (EBT), or pentoxifylline/vitamin E. Two-dimensional regions of interest (ROIs) were drawn on proton-density or T2-weighted MRI for radiomics feature analysis, and corresponding T2-maps. Comparisons were made between baseline and follow-up T2 relaxation times and radiomics features: Shannon's entropy, kurtosis, skewness, mean of positive pixels (MPP), and uniformity of distribution of positive gray-level pixel values (UPP).

RESULTS

There were 19 nodules in 13 subjects. Mean patient age was 60 years; 62% (8/13) were female; mean follow-up was 9.7 months. Nodule diameter at baseline averaged 18.2 mm (std dev 16.2 mm) and decreased almost 10% to 16.6 mm (p = 0.1, paired t-test). Normalized T2 signal intensity decreased 23% from 0.71 to 0.55 (p = 0.03, paired t-test). T2 relaxation time decreased 16% from 46.5 to 39.1 ms (p < 0.001, paired t-test). Among radiomics features, skewness increased to 0.71 from 0.41 (p = 0.03, paired t-test), and entropy decreased from 8.37 to 8.03 (p = 0.05, paired t-test); differences in other radiomics features were not significant.

CONCLUSIONS

Radiomics analysis and T2-mapping of superficial fibromatosis is feasible; robust decreases in absolute T2 relaxation time, and changes in image textural features (increased skewness and decreased entropy) offer novel imaging biomarkers of nodule collagenization and maturation.

Measuring and Teaching Confidence Calibration Among Radiologists: A Multi-Institution Study

OBJECTIVE

Our purpose was to assess the calibration of resident, fellow, and attending radiologists on a simple image classification task (presence or absence of an anterior cruciate ligament [ACL] tear based on interpretation of sagittal proton density, fat-saturated MR images) and to assess whether teaching residents could improve their calibration.

METHODS

We created a test containing 30 randomized, sagittal, proton density, fat-saturated MR images of the ACL (15 normal, 15 torn). This test was administered in person to 20 trainees and 3 attendings at one medical center in one state. An online version of the test was given to 23 trainees and 14 attendings from 11 other medical centers in nine other states. Subjects were asked to give their confidence level (0%-100%) that each ACL was torn.

RESULTS

Cross-sectional data were collected from 60 radiologists (mean time after medical school = 9.3 years, minimum = 1 year, maximum = 36 years). This demonstrated a statistically significant improvement in calibration as a function of increasing experience (P = .020). Longitudinal data were collected from 12 trainees at the start and end of their musculoskeletal radiology rotation, with an intervening review of the primary and secondary signs of ACL tear on MR. A statistically significant improvement in calibration was noted during the rotation (P = .028).

CONCLUSIONS

Confidence calibration is a promising tool for quality improvement and radiologist self-assessment. Our study showed that calibration loss improves with experience in radiologists tested on a common and clinically important image classification task. We also demonstrated that calibration can be successfully taught to residents over a relatively short period (2-4 weeks).

Small soft tissue masses indeterminate at imaging: histological diagnoses at a tertiary orthopedic oncology clinic

OBJECTIVE

To review histologic diagnoses of soft-tissue masses (STMs) ≤ 2 cm with indeterminate imaging features encountered in musculoskeletal oncology clinic at a tertiary referral center.

MATERIALS AND METHODS

This was an IRB-approved retrospective review of patients with STMs ≤ 2 cm, referred to our tertiary care orthopedic oncology clinic over 4.75 consecutive years. Maximum diameter was based on imaging measurement by a fellowship-trained musculoskeletal radiologist. Simple lipomas, synovial cysts, metastases, and cases without histologic confirmation were excluded. Patient demographics, tumor imaging features (location, depth, size, and tumor:muscle enhancement and T2 signal ratios), and histology were recorded and compared.

RESULTS

Mean maximum diameter for 42 trunk/extremity STMs was 1.5 cm (range, 0.7 to 2 cm). Mean age was 48 years (range, 18-83 years). Nine (21%) of the masses were malignant, while 33 (79%) were non-malignant. Thirty-nine (93%) of masses were superficial; 7/39 (18%) of these superficial tumors were malignant. Malignancy was not associated with underlying vessels, tendon, or fascia (p = 0.19). The non-malignant vs. malignant tumor:muscle enhancement ratio was 2.15 vs. 2.32 (p = 0.58) and enhancement coefficient of variation was 0.14 vs. 0.10 (p = 0.29). Most common malignant histologic subtypes were synovial sarcoma (n = 3), fibroblastic/myofibroblastic sarcoma (n = 2), leiomyosarcoma (n = 2), myxofibrosarcoma (n = 1), and angiomatoid fibrous histiocytoma (n = 1). The majority (67%) of non-malignant lesions were: leiomyoma (n = 6), angiomyoma (n = 5), schwannoma (n = 4), benign fibrous histiocytoma (n = 4), and hemangioma (n = 3).

CONCLUSIONS

At a tertiary musculoskeletal oncology referral clinic, primary STMs ≤ 2 cm with indeterminate imaging features should be managed cautiously despite their small size and/or superficial location.

Axitinib plus pembrolizumab in patients with advanced sarcomas including alveolar soft-part sarcoma: a single-centre, single-arm, phase 2 trial

BACKGROUND

VEGF promotes an immunosuppressive microenvironment and contributes to immune checkpoint inhibitor resistance in cancer. We aimed to assess the activity of the VEGF receptor tyrosine-kinase inhibitor axitinib plus the anti-PD-1 immune checkpoint inhibitor pembrolizumab in patients with sarcoma.

METHODS

This single-centre, single-arm, phase 2 trial was undertaken at a tertiary care academic medical centre in Miami, FL, USA, and participants were recruited from all over the USA and internationally. Patients were eligible if they were aged 16 years or older, and had histologically confirmed advanced or metastatic sarcomas, including alveolar soft-part sarcoma (ASPS); measurable disease with one site amenable to repeated biopsies; an ECOG performance status of 0-1; and progressive disease after previous treatment with at least one line of systemic therapy (unless no standard treatment existed or the patient declined therapy). The first five patients were enrolled in a lead-in cohort and were given axitinib 5 mg orally twice daily and pembrolizumab 200 mg intravenously for 30 min on day 8 and every 3 weeks for cycles of 6 weeks for up to 2 years. Thereafter, patients received escalating doses of axitinib (2-10 mg) plus flat dose pembrolizumab according to the schedule above. The primary endpoint was 3-month progression-free survival. All patients were evaluable for survival and safety analyses. This study is registered with ClinicalTrials.gov, number NCT02636725, and is closed to accrual.

FINDINGS

Between April 19, 2016, and Feb 7, 2018, of 36 patients assessed for eligibility, 33 (92%) were enrolled and given study treatment (intention-to-treat population and safety population), 12 (36%) of whom had ASPS. With a median follow-up of 14·7 months (IQR 10·1-19·1), 3-month progression-free survival for all evaluable patients was 65·6% (95% CI 46·6-79·3). For patients with ASPS, 3-month progression-free survival was 72·7% (95% CI 37·1-90·3). The most common grade 3 or 4 treatment-related adverse events included hypertension (five [15%] of 33 patients), autoimmune toxicities (five [15%]), nausea or vomiting (two [6%]), and seizures (two [6%]). Serious treatment-related adverse events occurred in seven (21%) patients, including autoimmune colitis, transaminitis, pneumothorax, haemoptysis, seizures, and hypertriglyceridemia. There were no treatment-related deaths.

INTERPRETATION

Axitinib plus pembrolizumab has manageable toxicity and preliminary activity in patients with advanced sarcomas, particularly patients with ASPS, warranting further investigation in randomised controlled trials.

FUNDING

Merck, Pfizer, American Cancer Society, and Sylvester Comprehensive Cancer Center.

Performance of an Interactive Upper Extremity Peripheral Nerve Training Module Among Medical Students, Radiology Residents, and Fellows: A Multi-institutional Study

BACKGROUND AND PURPOSE

Chronic pain is a common problem and imaging is becoming increasingly utilized in the characterization of peripheral neuropathy, although this topic is not emphasized during medical training. We hypothesized that an electronic module and nerve atlas would be effective in improving comprehension among trainees.

MATERIALS AND METHODS

In this IRB-approved study, a training module was created that included a side-by-side comparison of normal upper extremity nerves on magnetic resonance imaging and ultrasound (US), with embedded questions and cases, followed by a brief hands-on US scanning session. Thirty volunteers with variable training were enrolled in 1 institution, while 14 volunteers were enrolled in another. Pre- and post-test scores were collected and compared.

RESULTS

There was a response rate of 100% at both institutions. At the first institution, subjects were divided into 2 groups: group 1 (16 medical students) and group 2 (14 residents/fellows). There was a baseline deficit of knowledge among both groups, with a mean pretest score of 37.5% and 47.5% for group 1 and group 2, respectively (P = 0.017). After module completion, both groups improved with a mean post-test score of 67.2% for group 1 and 76.1% for group 2. At the second institution, there was similar improvement even if the scanning session was not done.

CONCLUSIONS

Use of an electronic module helps trainees to become more familiar with peripheral nerve imaging, regardless of level of training. Use of the module, even in the absence of hands-on US scanning, results in an improved understanding of this topic.

Local recurrence of soft-tissue sarcoma: issues in imaging surveillance strategy

Soft-tissue sarcomas pose diagnostic and therapeutic challenges to physicians, owing to the large number of subtypes, aggressive tumor biology, lack of consensus on management, and controversy surrounding interval and duration of surveillance scans. Advances in multidisciplinary management have improved the care of sarcoma patients, but controversy remains regarding strategies for surveillance following definitive local control. This review provides an updated, comprehensive overview of the current understanding of the risk of local recurrence of soft-tissue sarcoma, by examining the literature based on features such as histological type and grade, tumor size, and resection margin status, with the aim of helping clinicians, surgeons, and radiologists to develop a tailored approach to local imaging surveillance.

MRI findings associated with microscopic residual tumor following unplanned excision of soft tissue sarcomas in the extremities

INTRODUCTION

MRI is often used to determine the presence of residual disease following unplanned excisions (UPE) of soft tissue sarcomas (STS). We sought to identify MRI features associated with histologic evidence of residual disease after TBE.

MATERIALS AND METHODS

This was an IRB-approved retrospective review of 27 patients with R1-type UPE of STS over a 32-month period, with subsequent MRI and TBE. MRI studies were retrospectively evaluated to determine depth of tissue involvement, presence of nodular enhancement, and maximum length of soft tissue edema normalized to extremity size. MRI findings were correlated with histology from unplanned excision and TBE.

RESULTS

Among the 21 subjects, there were 13 males and 8 females, mean age 58. Eighteen of 21 STS were grade 2 or 3. Deep compartments were involved in 5/21 cases. Original margins were positive in 17/21 UPE, with inadequate margin assessment in the remaining 4 cases. Residual tumor was present at TBE in 11/21 cases; it was found in 4/6 cases with nodular enhancement and 7/15 cases without nodular enhancement (sensitivity = 0.36; specificity = 0.80; PPV = 0.67; NPV = 0.53). Increased extent of soft tissue edema increased the likelihood of residual tumor at TBE (OR = 35.0; 95% CI = 1.6 to 752.7; p = 0.023).

CONCLUSION

Nodular enhancement is neither sensitive nor specific in predicting residual microscopic tumor in TBE following UPE. Extensive soft tissue edema on MRI after UPE increases the likelihood of finding a residual microscopic tumor, justifying ample margins at TBE and consideration of adjuvant therapy.

T2 signal intensity as an imaging biomarker for patients with superficial Fibromatoses of the hands (Dupuytren's disease) and feet (Ledderhose disease) undergoing definitive electron beam irradiation

OBJECTIVE

Electron beam therapy is a definitive radiation treatment option for superficial fibromatoses of the hands and feet. Because objective criteria for treatment response remain poorly defined, we sought to describe changes in electron beam treated lesions on MRI.

MATERIALS AND METHODS

The study included 1 male and 9 female patients with a total of 37 superficial fibromatoses; average age was 60.7 years. Standard 6 MeV electron beam treatment included 3 Gy per fraction for 10 or 12 treatments using split-course with 3-month halfway break. Pre- and post-treatment MRIs were evaluated to determine lesion size (cm3), T2 signal intensity and contrast enhancement (5-point ordinal scales) by a fellowship trained musculoskeletal radiologist. MRI findings were correlated with clinical response using a composite 1-5 ordinal scale, Karnofsky Performance Scale and patient-reported 10-point visual analog scale for pain.

RESULTS

Mean volume decreased from 1.5 to 1.2 cm³ (p = 0.01, paired t-test). Mean T2 hyperintensity score decreased from 3.0 to 2.1 (p < 0.0001, Wilcoxon signed-rank). Mean enhancement score available for 22 lesions decreased from 3.8 to 3.0 (p < 0.0001, Wilcoxon signed-rank). Performance scores improved from 78.9 ± 13.7 to 84.6 ± 6.9 (p = 0.007, paired t-test). Pain scores decreased from 3.0 ± 3.3 to 1.1 ± 2.0 (p = 0.0001, paired t-test). Post-treatment T2 signal correlated weakly with performance and pain (Spearman's ρ = -0.37 and 0.16, respectively).

CONCLUSIONS

MRI is valuable for evaluating patients undergoing electron beam therapy for superficial fibromatoses: higher pretreatment T2 intensity may predict benefit from radiotherapy. T2 hypointensity may be a better marker than size for therapeutic effect.

Does Vasopressin Exacerbate Cerebral Edema in Patients with Severe Traumatic Brain Injury?

Arginine vasopressin (AVP) is often used as an alternative pressor to catecholamines (CATs). However, unlike CATs, AVP is a powerful antidiuretic that could promote edema. We tested the hypothesis that AVP promoted cerebral edema and/or increased requirements for osmotherapy, relative to those who received CATs, for cerebral perfusion pressure (CPP) management after traumatic brain injury (TBI). This is a retrospective review of 286 consecutive TBI patients with intracranial pressure monitoring at a single institution from September 2008 to January 2015. Cerebral edema was quantitated using CT attenuation in prespecified areas of gray and white matter. Results: To maintain CPP >60 mm Hg, 205 patients required no vasopressors, 41 received a single CAT, 12 received AVP, and 28 required both. Those who required no pressors were generally less injured; required less hyperosmolar therapy and less total fluid; and had lower plasma Na, lower intracranial pressure, less edema, and lower mortality (all P < 0.05). Edema; daily mean, minimum, and maximum Na levels; and mortality were similar with AVP versus CATs, but the daily requirement of mannitol and 3 per cent NaCl were reduced by 45 and 35 per cent (both P < 0.05). In patients with TBI who required CPP therapy, AVP reduced the requirements for hyperosmolar therapy and did not delay resolution or increase cerebral edema compared with CATs.

Pitfalls in soft tissue sarcoma imaging: chronic expanding hematomas

Solid or nodular enhancement is typical of soft tissue sarcomas although high grade soft tissue sarcomas and those with internal hemorrhage often appear heterogeneous with areas of nonenhancement and solid or nodular enhancement. These MRI findings often prompt an orthopedic oncology referral, a biopsy or surgery. However, not all masses with these imaging findings are malignant. We report the multimodality imaging findings of two surgically proven chronic expanding hematomas (CEH) with imaging features that mimicked sarcomas. A third case of nonenhancing CEH of the lower extremity is also presented as a comparison. It is important that in the correct clinical scenario with typical imaging findings, the differential diagnosis of a chronic expanding hematoma be included in the workup of these patients. An image-guided biopsy of nodular tissue within such masses that proves to be negative for malignancy should not necessarily be considered discordant. A correct diagnosis may prevent a morbid unnecessary surgery and may indicate the need for a conservative noninvasive follow-up with imaging.

Does Vasopressin Exacerbate Cerebral Edema in Patients with Severe Traumatic Brain Injury?

Arginine vasopressin (AVP) is often used as an alternative pressor to catecholamines (CATs). However, unlike CATs, AVP is a powerful antidiuretic that could promote edema. We tested the hypothesis that AVP promoted cerebral edema and/or increased requirements for osmotherapy, relative to those who received CATs, for cerebral perfusion pressure (CPP) management after traumatic brain injury (TBI). This is a retrospective review of 286 consecutive TBI patients with intracranial pressure monitoring at a single institution from September 2008 to January 2015. Cerebral edema was quantitated using CT attenuation in prespecified areas of gray and white matter.

RESULTS

To maintain CPP >60 mm Hg, 205 patients required no vasopressors, 41 received a single CAT, 12 received AVP, and 28 required both. Those who required no pressors were generally less injured; required less hyperosmolar therapy and less total fluid; and had lower plasma Na, lower intracranial pressure, less edema, and lower mortality (all P < 0.05). Edema; daily mean, minimum, and maximum Na levels; and mortality were similar with AVP versus CATs, but the daily requirement of mannitol and 3 per cent NaCl were reduced by 45 and 35 per cent (both P < 0.05). In patients with TBI who required CPP therapy, AVP reduced the requirements for hyperosmolar therapy and did not delay resolution or increase cerebral edema compared with CATs.

F-18 FDG PET differentiation of benign from malignant chondroid neoplasms: a systematic review of the literature

INTRODUCTION

Discriminating among benign chondroid tumors, low-grade chondrosarcomas, and grade 2/3 chondrosarcomas is frequently difficult with standard imaging modalities. We systematically reviewed the literature to determine the performance of PET-CT in making this distinction.

METHODS

A systematic review was performed identifying 811 PubMed- and Embase-indexed articles containing combinations of "chondrosarcoma," "enchondroma," "chondroid," "cartilage" and "PET/CT," "PET," "positron." Eight articles including 166 lesions were included. Age, gender, tumor size, histologic grade, and SUVmax values were extracted for individual lesions when possible and otherwise recorded as aggregated data. Comparisons in SUVmax among benign, low-grade, and intermediate-/high-grade chondroid neoplasms were made.

RESULTS

Individual SUVs were available for 101 lesions; 65 additional lesions were reported as aggregated data. There were 101 malignant and 65 benign tumors. Benign tumors were seen more frequently in females (p = 0.04, Fischer's exact test), but malignancy was not associated with age or lesion size. SUVmax was lower for benign (1.6 ± 0.7) than malignant tumors (4.4 ± 2.5) (p < 0.0001, t-test). SUVmax was lower for grade 0/1 (2.0 ± 0.7) than grade 2/3 (6.0 ± 3.2) (p < 0.0001, t-test). Increasing SUVmax correlated with higher grade chondroid tumors (Spearman's rank, ρ = 0.78). SUVmax ≥4.4 was 99% specific for grade 2/3 chondrosarcoma.

CONCLUSIONS

SUVmax correlates with histologic grade in intraosseous chondroid neoplasms; very low SUVmax supports a diagnosis of benign tumor, while elevated SUVmax is suggestive of higher grade chondrosarcoma.

Anatomic Relationship and Imaging Relevance of the Perforating Branches of the Peroneal Vessels to the Anterior Talofibular Ligament

BACKGROUND

Patients frequently present to the emergency department after ankle injuries, and the anterior talofibular ligament (ATFL) is commonly damaged. Musculoskeletal ultrasound (US) can help to make a rapid diagnosis. There is a paucity of literature describing techniques to image the ATFL with US, and the complex ankle anatomy and potential pitfalls make imaging challenging.

OBJECTIVE

Our aim was to estimate prevalence of perforating branches (PBs) of the peroneal vessels and determine their most frequent position relative to the ATFL. If these vessels are located in a predictable position at the level of the ATFL, they may serve as a sonographic landmark for the correct imaging plane.

METHODS

Magnetic resonance imaging (MRI) scans of 105 ankles were reviewed to determine the PB prevalence and location at the ATFL. Inter-observer agreement was determined. Additionally, 16 ankles from 8 asymptomatic subjects were scanned using a high-frequency linear transducer and PB prevalence and location were noted.

RESULTS

By MRI, PBs were detected in 85% of the ankles and 93% of ankles after consensus. In 73% of cases with agreed PB visualization, vessels assumed a medial position with respect to the ATFL. By US, PBs could be seen in 100% of cases, with the arterial PB seen in 81% of cases and assuming a medial position in 88%.

CONCLUSIONS

PBs are often present, have a predictable course, and may be useful to help optimize US probe positioning when assessing the ATFL.

Baseline Cartilage Thickness and Meniscus Extrusion Predict Longitudinal Cartilage Loss by Quantitative Magnetic Resonance Imaging: Data From the Osteoarthritis Initiative

OBJECTIVE

This study aimed to assess how meniscus damage and baseline cartilage thickness influence the rate of cartilage loss and knee pain.

METHODS

Of 4796 participants in the Osteoarthritis Initiative, 86 had baseline and 48-month follow-up quantitative magnetic resonance imaging data for medial compartment cartilage thickness. Baseline meniscus pathology was scored by a musculoskeletal radiologist using Whole-Organ Magnetic Resonance Imaging Score. Findings were correlated with 72-month Knee injury and Osteoarthritis Outcome Score.

RESULTS

Univariate analysis showed cartilage change was not influenced by demographic variables. Multivariable regression revealed that initial cartilage thickness (-1.07 mm at 48 months for every 1 mm decrease at baseline, P < 0.001) and meniscus extrusion (-0.33 mm if present at baseline, P < 0.001) were the strongest predictors of medial compartment cartilage thickness at 48 months. Knee injury and Osteoarthritis Outcome Score pain scores did not correlate with cartilage loss.

CONCLUSIONS

Baseline cartilage thickness and meniscus extrusion are important and independent predictors for accelerated cartilage loss. However, the degree of cartilage loss did not correlate with midterm change in clinical outcome scores.

Rare Dual Lesion: Extraskeletal Osteosarcoma Developing Within a Simple Lipoma

Extraosseous osteosarcoma is a rare malignancy, but simple lipomas are common. This article is the first report of a case of radiation-induced extraosseous osteosarcoma that developed within a simple lipoma in a 72-year-old woman. We correlate the magnetic resonance imaging, computed tomography, positron emission tomography, and plain radiographic findings. The patient, treated with systemic therapy and wide surgical resection of the neoplasm, remained clinically free of disease during the first 22 months of follow-up.

Desmoid fibromatosis: MRI features of response to systemic therapy

OBJECTIVE

Imaging criteria for measuring the response of desmoid fibromatosis to systemic therapy are not well established. We evaluated a series of patients with desmoids who underwent systemic therapy to document magnetic resonance imaging (MRI) features associated with a positive clinical response.

MATERIALS AND METHODS

This Institutional Review Board-approved retrospective study included 23 patients (mean age 40.5) with 29 extra-abdominal tumors. Therapeutic regimens included cytotoxic chemotherapy (n = 19), targeted therapy (n = 3), and nonsteroid anti-inflammatory drugs (NSAIDS; n = 1). Clinical effects were categorized as progressive disease, stable, or partial response. Maximum tumor dimension (Dmax), approximate tumor volume (VTumor), and quantitative tumor T2 hyperintensity and contrast enhancement (relative to muscle) for pre- and post-treatment MRIs were compared.

RESULTS

Three lesions progressed, 5 lesions were stable, whereas 21 showed a clinical response. Dmax decreased more in responders (mean -11.0 %) than in stable/progressive lesions (mean -3.6 and 0 % respectively, p = 0.28, ANOVA); by Response Evaluation Criteria in Solid Tumors (RECIST 1.1) 27 out of 29 lesions were "stable," including the 3 progressive lesions. In responders, VTumor change averaged -29.4 %, but -19.2 % and +32.5 % in stable and progressive lesions respectively (p = 0.002, ANOVA); by 3D criteria 14 out of 29 lesions showed a partial response. T2 hyperintensity decreased by 50-54 % in partial response/stable disease, but only by 10 % in progressive lesions (p = 0.049, t test). Changes in contrast enhancement ranged from -23 % to 0 %, but were not statistically significant among response groups (p = 0.37). Change in T2 hyperintensity showed a positive correlation with volumetric change (r = 0.40).

CONCLUSION

Decreases in volume and T2 hyperintensity reflect the positive response of desmoid fibromatosis to systemic therapy; RECIST 1.1 criteria are not sensitive to clinically determined tumor response.

The histological variants of liposarcoma: predictive MRI findings with prognostic implications, management, follow-up, and differential diagnosis

Liposarcoma is the single most common soft tissue sarcoma accounting for up to 35 % of sarcomas. It represents a histologically diverse group of soft tissue tumors that demonstrate a wide range of imaging appearances with varied behavior patterns. Correspondingly, more aggressive histological subtypes often require management that includes a combination of surgery, chemotherapy, and radiation therapy. Distinguishing among liposarcoma subtypes has important therapeutic and prognostic implications. In this manuscript, we review the liposarcoma subtypes and their histologic and MRI findings, prognostic implications, and differential diagnostic considerations.

Incidence of tendon entrapment and dislocation with calcaneus and pilon fractures on CT examination

OBJECTIVE

To examine the association between tibial pilon and calcaneal fracture classification and tendon entrapment or dislocation.

MATERIALS AND METHODS

After institutional review board approval, we retrospectively reviewed consecutive CT scans with calcaneal or pilon fractures from 5 years at a level 1 trauma center. We categorized calcaneal fractures according to the Sanders classification, and pilon fractures according to the Ruedi and Allgower and the Arbeitsgemeinschaft für Osteosynthesefragen-Orthopaedic Trauma Association (AO-OTA) classifications. Ankle tendons were assessed for dislocation or entrapment. Fisher's exact test was used for statistical analysis with significance at p < 0.05.

RESULTS

A total of 312 fractures (91 pilon only, 193 calcaneal only, and 14 ankles with ipsilateral pilon and calcaneal fractures) were identified in 273 patients. Twenty-two pilon, 42 calcaneal, and nine combination fractures were associated with 99 occurrences of tendon entrapment or superior peroneal retinacular injury. Such findings were associated with multiple fractures (p = 0.002). Multifragmentary pilon fractures were associated with posterior tibial and flexor digitorum longus tendon entrapment (p < 0.0001 and p = 0.0003 for Ruedi/Allgower and AO-OTA, respectively), and multifragmentary Sanders type 3 or 4 calcaneal fractures were associated with superior peroneal retinacular injury (p = 0.0473) compared to simple fracture patterns. Thirty-nine percent of tendon entrapments or retinacular injuries were prospectively identified, 85 % by musculoskeletal radiologists (p < 0.0001).

CONCLUSIONS

Approximately 25 % of calcaneal and pilon fractures were retrospectively identified to contain posteromedial tendon entrapment or superior peroneal retinacular injury. Radiologists should meticulously search for such injuries, particularly when analyzing multifragmentary and multiple fractures.

Apparent diffusion coefficient map of a case of extramedullary plasmacytoma

Plasmacytomas are rare tumors, which arise from the monoclonal proliferation of malignant plasma cells. They may affect either the bony skeleton or rarely the soft tissues, the latter being referred to as extramedullary or extraosseous. We report a case of an extramedullary plasmacytoma that presented as a soft tissue mass involving the muscles of the left leg, in a patient who was previously treated for multiple myeloma. We describe the MR Imaging characteristics of the tumor and highlight the usefulness of diffusion-weighted imaging with apparent diffusion coefficient mapping.

Volumetric segmentation of ADC maps and utility of standard deviation as measure of tumor heterogeneity in soft tissue tumors

PURPOSE

Determine interobserver concordance of semiautomated three-dimensional volumetric and two-dimensional manual measurements of apparent diffusion coefficient (ADC) values in soft tissue masses (STMs) and explore standard deviation (SD) as a measure of tumor ADC heterogeneity.

RESULTS

Concordance correlation coefficients for mean ADC increased with more extensive sampling. Agreement on the SD of tumor ADC values was better for large regions of interest and multislice methods. Correlation between mean and SD ADC was low, suggesting that these parameters are relatively independent.

CONCLUSION

Mean ADC of STMs can be determined by volumetric quantification with high interobserver agreement. STM heterogeneity merits further investigation as a potential imaging biomarker that complements other functional magnetic resonance imaging parameters.

Diffusion-weighted MR imaging for characterizing musculoskeletal lesions

Diffusion-weighted (DW) imaging is a functional magnetic resonance (MR) imaging technique that can readily be incorporated into a routine non-contrast material-enhanced MR imaging protocol with little additional scanning time. DW imaging is based on changes in the Brownian motion of water molecules caused by tissue microstructure. The apparent diffusion coefficient (ADC) is a quantitative measure of Brownian movement: Low ADC values typically reflect highly cellular microenvironments in which diffusion is restricted by the presence of cell membranes, whereas acellular regions allow free diffusion and result in elevated ADC values. Thus, with ADC mapping, one may derive useful quantitative information regarding the cellularity of a musculoskeletal lesion using a nonenhanced technique. The role of localized DW imaging in differentiating malignant from benign osseous and soft-tissue lesions is still evolving; when carefully applied, however, this modality has proved helpful in a subset of tumor types, such as nonmyxoid soft-tissue tumors. Studies of the use of DW imaging in assessing the treatment response of both osseous and soft-tissue tumors have shown that higher ADC values correlate with better response to cytotoxic therapy. Successful application of DW imaging in the evaluation of musculoskeletal lesions requires familiarity with potential diagnostic pitfalls that stem from technical artifacts and confounding factors unrelated to lesion cellularity. Further investigation is needed to evaluate the impact of DW imaging-ADC mapping on management and outcome in patients with musculoskeletal lesions.

The utility of ultrasound in the assessment of traumatic peripheral nerve lesions: report of 4 cases

Ultrasound technology continues to improve with better image resolution and availability. Its use in evaluating peripheral nerve lesions is increasing. The current review focuses on the utility of ultrasound in traumatic injuries. In this report, the authors present 4 illustrative cases in which high-resolution ultrasound dramatically enhanced the anatomical understanding and surgical planning of traumatic peripheral nerve lesions. Cases include a lacerating injury of the sciatic nerve at the popliteal fossa, a femoral nerve injury from a pseudoaneurysm, an ulnar nerve neuroma after attempted repair with a conduit, and, finally, a spinal accessory nerve injury after biopsy of a supraclavicular fossa lesion. Preoperative ultrasound images and intraoperative pictures are presented with a focus on how ultrasound aided with surgical decision making. These cases are set into context with a review of the literature on peripheral nerve ultrasound and a comparison between ultrasound and MRI modalities.

Interobserver variability of selective region-of-interest measurement protocols for quantitative diffusion weighted imaging in soft tissue masses: Comparison with whole tumor volume measurements

BACKGROUND

To assess the interobserver reliability of three selective region-of-interest (ROI) measurement protocols for apparent diffusion coefficient (ADC) quantifications in soft tissue masses (STMs) compared with whole tumor volume (WTV) ADC measurements.

METHODS

Institutional review board approval was obtained and informed consent was waived. Three observers independently measured minimum and mean ADCs of 73 benign and malignant musculoskeletal STMs using three selective methods (single-slice [SS], predefined three slices [PD], observer-based [OB]) and WTV measurements at 3.0 Tesla. Minimum and mean ADC values derived from each method were compared with WTV measurements, and inter-reader variation was assessed using the intraclass correlation coefficient (ICC). The time required for each method of ADC measurement was recorded.

RESULTS

For the SS, PD, OB, and WTV methods, minimum ADC values ((×10(-3) mm2 /s)) were 0.97, 0.78, 0.73, and 0.67, respectively, and mean ADC values ((×10(-3) mm2 /s)) were 1.49, 1.49, 1.51, and 1.49, respectively. Interobserver agreement was good to excellent for the minimum and mean ADC values for the three readers using the SS, PD, OB, and WTV (ICC range 0.78-0.90). The SS, PD and OB methods required the least amount of measurement time (14 ± 5, 40 ± 17, and 38 ± 15 s, respectively) while the reference WTV method required the longest measurement time (111 ± 54 s) (P < 0.01).

CONCLUSION

While all selective and WTV measurements offer good to excellent interobserver agreement, the selective OB method of ADC measurement results in the closest values to WTV measurements and requires significantly less measurement time than that required for the WTV method.

Imaging of tarsal navicular disorders: a pictorial review

The tarsal navicular is a bone within the midfoot that plays a critical role in maintaining the arch of the foot. This bone is clinically relevant because it may be affected by a wide array of pathologies. Our approach includes a detailed description of the imaging characteristics and disorders affecting the tarsal navicular. Organization includes (a) normal imaging, (b) accessory ossicles, (c) coalition, (d) fractures, (e) Kohler's disease, (f) osteonecrosis, (g) osteochondral lesions, (h) arthropathies, and (i) tumors. The purpose of this article is to discuss normal variants and pathological processes that can affect the tarsal navicular, with emphasis on the often-overlooked imaging findings.

Characterization of peripheral nerve sheath tumors with 3T proton MR spectroscopy

BACKGROUND AND PURPOSE

The characterization of peripheral nerve sheath tumors is challenging. The purpose here was to investigate the diagnostic value of quantitative proton MR spectroscopy at 3T for the characterization of peripheral nerve sheath tumors as benign or malignant, compared with PET.

MATERIALS AND METHODS

Twenty participants with 24 peripheral nerve sheath tumors underwent MR spectroscopy by use of a point-resolved sequence (TE, 135 ms). Six voxels were placed in 4 histologically proven malignant peripheral nerve sheath tumors and 22 voxels in 20 benign peripheral nerve sheath tumors (9 histologically proven, 11 with documented stability). The presence or absence of a trimethylamine signal was evaluated, the trimethylamine concentration estimated by use of phantom replacement methodology, and the trimethylamine fraction relative to Cr measured. MR spectroscopy results for benign and malignant peripheral nerve sheath tumors were compared by use of a Mann-Whitney test, and concordance or discordance with PET findings was recorded.

RESULTS

In all malignant tumors and in 9 of 18 benign peripheral nerve sheath tumors, a trimethylamine peak was detected, offering the presence of trimethylamine as a sensitive (100%), but not specific (50%), marker of malignant disease. Trimethylamine concentrations (2.2 ± 2.8 vs 6.6 ± 5.8 institutional units; P < .049) and the trimethylamine fraction (27 ± 42 vs 88 ± 22%; P < .012) were lower in benign than malignant peripheral nerve sheath tumors. A trimethylamine fraction threshold of 50% resulted in 100% sensitivity (95% CI, 58.0%-100%) and 72.2% (95% CI, 59.5%-75%) specificity for distinguishing benign from malignant disease. MR spectroscopy and PET results were concordant in 12 of 16 cases, (2 false-positive results for MR spectroscopy and PET each).

CONCLUSIONS

Quantitative measurement of trimethylamine concentration by use of MR spectroscopy is feasible in peripheral nerve sheath tumors and shows promise as a method for the differentiation of benign and malignant lesions. Trimethylamine presence within a peripheral nerve sheath tumor is a sensitive marker of malignant disease, but quantitative measurement of trimethylamine content is required to improve specificity.

Characterization of soft tissue masses: can quantitative diffusion weighted imaging reliably distinguish cysts from solid masses?

OBJECTIVE

To investigate the accuracy of quantitative diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) mapping for characterizing soft tissue masses (STMs) as cysts or solid masses.

MATERIALS AND METHODS

This IRB-approved retrospective study included 36 subjects with 37 STMs imaged by conventional MRI (T1-weighted, T2-weighted, contrast-enhanced T1-weighted sequences) and DWI (b-values 50, 400, 800 s/mm(2)) with ADC mapping. STMs were defined as non-solid cysts by histology or clinical follow-up, and as solid by histology. For each STM, ADC values (range, mean) were recorded by two observers. Differences between ADC values in cysts and solid STMs were compared using Wilcoxon rank-sum and receiver-operating characteristic (ROC) analysis.

RESULTS

There were higher minimum (1.65 vs 0.68, p = 0.003) and mean (2.31 vs 1.45, p = 0.005) ADC values in cysts than solid STMs respectively. Areas under the ROC for minimum and mean ADC values were 0.82 and 0.81 respectively. Using threshold ADC values of 1.8 (minimum) or 2.5 (mean) yielded a sensitivity of 60 % and 80 % respectively, and a specificity of 100 % for classifying a STM as a cyst; for tumors with high fluid-signal intensity, the performance of these threshold values was maintained.

CONCLUSION

Diffusion-weighted imaging with ADC mapping provides a non-contrast MRI alternative for the characterization of STMs as cysts or solid masses. Threshold ADC values exist that provide 100 % specificity for differentiating cysts and solid STMs, even for tumors of high fluid-signal intensity on T2-weighted images.

"Cystic"-appearing soft tissue masses: what is the role of anatomic, functional, and metabolic MR imaging techniques in their characterization?

Although conventional MR imaging with contrast-enhanced T1-weighted sequences is of paramount importance for evaluating soft tissue masses, noncontrast MR sequences have emerged that facilitate their characterization. In this article, the utility and pitfalls of conventional MR imaging with T1-weighted, fluid-sensitive, and contrast-enhanced sequences will be discussed, along with that of functional (diffusion weighted imaging) and metabolic (proton MR spectroscopy) non-contrast-enhanced techniques for the purpose of soft tissue mass characterization. In particular, we discuss the application of these techniques to differentiating neoplastic or inflammatory masses that have high fluid content from benign cysts, as this distinction is a common pitfall of conventional sequences.

Lymphoproliferative disorders of the kidney on fine-needle aspiration: cytomorphology and radiographic correlates in 33 cases

BACKGROUND

Unless renal lesions present in the setting of widespread lymphoma, biopsy can be indicated to differentiate from metastases, hypovascular renal cell carcinoma, urothelial carcinoma or infection. We review our experience with lymphoproliferative disorders in the kidney diagnosed by fine-needle aspiration (FNA), and focus on clinicopathologic and radiographic features.

DESIGN

All cases of non-Hodgkin lymphoma diagnosed on renal FNA at 2 academic institutions between 1989 and 2011 were reviewed. Clinical history, radiographic and cytomorphologic features, and follow-up were assessed.

RESULTS

33 cases were identified, with 15 primary tumors and 18 recurrences/secondary tumors including 1 acute lymphoblastic lymphoma. The majority were aggressive/high-grade lesions (25/33). 25 cases were substantiated by positive flow cytometry results. Most were detected at follow-up/incidentally. 22 cases showed multiple renal and/or retroperitoneal masses or a significant component of adenopathy; others showed a solitary renal mass. Salient radiologic features included hypodense, infiltrative and ill-defined masses. Cytomorphology showed a monotonous population of large atypical lymphoid cells, often with lymphoglandular bodies.

CONCLUSION

Cytologic diagnosis of renal lymphoma requires analysis of morphological, clinical and immunophenotypic information. Helpful features for diagnosis include: multiple masses on computed tomography, a monotonous population of abnormal cells in a background of lymphoglandular bodies and immunophenotyping demonstrating light chain restriction.

Magnetic resonance neurography of median neuropathies proximal to the carpal tunnel

This review provides magnetic resonance neurography (MRN) imaging appearances of median neuropathy proximal to the carpal tunnel. Carpal tunnel syndrome (CTS) and its imaging have been extensively described in the literature; however, there is a relative paucity of information on the MR imaging appearances of different pathologies of the median nerve proximal to the carpal tunnel.

Peripheral nerve surgery: the role of high-resolution MR neurography

High-resolution MRN is becoming increasingly available due to recent technical advancements, including higher magnetic field strengths (eg, 3T), 3D image acquisition, evolution of novel fat-suppression methods, and improved coil design. This review describes the MRN techniques for obtaining high-quality images of the peripheral nerves and their small branches and imaging findings in normal as well as injured nerves with relevant intraoperative correlations. Various microsurgical techniques in peripheral nerves, such as neurolysis, nerve repairs by using nerve grafts, and conduits are discussed, and MRN findings of surgically treated nerves are demonstrated.

Hairy cell leukemia presenting as a peripancreatic mass: cytomorphology and radiographic correlates

Hairy cell leukemia (HCL) usually presents with peripheral cytopenias, diffuse marrow infiltration, and splenomegaly. This chronic lymphoproliferative disorder is not typically associated with lymphadenopathy or mass lesions. We report a case of HCL first treated by splenectomy, followed by several years of interferon therapy. Twenty-five years later, the patient presented with weight loss, fatigue, and a large PET-avid mass surrounding the head of the pancreas. Fine-needle aspiration was pursued to investigate the unusual and infiltrative appearance of the lesion, which was suggestive of another primary malignancy. Cytology smears showed discohesive lymphoid cells with round nuclei and delicate cytoplasmic projections. Flow cytometry confirmed the presence of a clonal B-cell population with bright expression of CD20 as well as CD25 and CD103, diagnostic of HCL. This is the first report of HCL presenting as a peripancreatic mass. The importance of correlation with radiology and clinical history is emphasized when evaluating such lesions.

Large cell transformation of mycosis fungoides on fine needle aspiration: an unusual case mimicking classical Hodgkin lymphoma

Mycosis fungoides (MF), the most common type of primary cutaneous T-cell lymphoma, undergoes large cell transformation in only a minority of cases that present in patch stage. We describe a 52-year-old patient with a history of unilesional patch stage MF treated with localized radiotherapy. He had disease recurrence 5 years later and began psoralen plus ultraviolet A treatment with good response. After inguinal lymphadenopathy was detected on physical examination, a follow-up PET scan showed a fluorodeoxyglucose-avid inguinal node, which was evaluated by fine needle aspiration. Cytomorphology showed numerous Reed-Sternberg-like cells, highly suspicious for Hodgkin lymphoma. Histologic sections revealed isolated sinusoidal involvement by pleomorphic CD30-positive tumor cells, diagnostic of large cell transformation of MF in light of clinical history. The cells were also positive for CD15 and CD4. This case emphasizes morphologic features of an entity with limited description in the cytology literature and adds to the growing number of reported CD15-positive T-cell lymphomas.

High resolution imaging of tunnels by magnetic resonance neurography

Peripheral nerves often traverse confined fibro-osseous and fibro-muscular tunnels in the extremities, where they are particularly vulnerable to entrapment and compressive neuropathy. This gives rise to various tunnel syndromes, characterized by distinct patterns of muscular weakness and sensory deficits. This article focuses on several upper and lower extremity tunnels, in which direct visualization of the normal and abnormal nerve in question is possible with high resolution 3T MR neurography (MRN). MRN can also serve as a useful adjunct to clinical and electrophysiologic exams by discriminating adhesive lesions (perineural scar) from compressive lesions (such as tumor, ganglion, hypertrophic callous, or anomalous muscles) responsible for symptoms, thereby guiding appropriate treatment.

A quantitative method to assess focal acetabular overcoverage resulting from pincer deformity using CT data

BACKGROUND

Current assessment techniques for focal acetabular overcoverage are neither consistent nor quantitatively accurate.

QUESTIONS/PURPOSES

We propose: (1) a method to precisely quantify the amount of focal acetabular overcoverage in a patient's pincer deformity based on CT data; (2) to evaluate the consistency of this method; and (3) to compare the method with conventional radiographic assessments.

METHODS

We developed a method to assess focal acetabular overcoverage using points selected from CT scans along the acetabular rim after realigning the pelvis into a neutral position. Using four resampled and segmented pelvic CT scans of cadaveric specimens with virtually induced impingement, two observers independently tested the algorithm's consistency. Our algorithm assessed the amount of focal acetabular overcoverage using CT data and projected data from reconstructed radiographs.

RESULTS

(1) We successfully showed the feasibility of the software to produce consistent, quantitative measurements. (2) Testing showed the average difference between observers in aligning the pelvis was 0.42°, indicative of a consistent approach. (3) Differences between measurements on three-dimensional (3-D) CT and simulated radiographs were significant.

CONCLUSIONS

The proposed method represents a new avenue in consistently quantifying focal acetabular overcoverage using CT models while correcting for pelvic tilt and rotation. Our analysis confirms AP hip radiograph simulations overestimate the amount of overhanging acetabular rim in a pincer deformity.

CLINICAL RELEVANCE

This technique has potential to improve preoperative diagnostic accuracy and enhance surgical planning for correction of a pincer deformity resulting from focal acetabular overcoverage.

3T MR neurography using three-dimensional diffusion-weighted PSIF: technical issues and advantages

Three-dimensional (3D) diffusion-weighted reversed fast imaging with steady state precession (3D DW-PSIF) MR sequence has the potential to create nerve-specific images. The authors describe the technical issues and their initial experience with this imaging technique employed for peripheral MR neurography.

MR imaging of deltoid ligament pathologic findings and associated impingement syndromes

Injuries of the deltoid ligament of the ankle are increasingly recognized with the widespread use of magnetic resonance (MR) imaging. The use of higher magnetic field strengths requires familiarity with the anatomic substructure of the deltoid ligament to better localize and characterize pathologic findings. Specifically, improved image resolution allows components of the superficial (tibiocalcaneal, tibionavicular, posterior superficial tibiotalar, and tibiospring ligaments) and deep (anterior tibiotalar and posterior deep tibiotalar ligaments) portions of the ligament to be evaluated separately. Awareness of the deltoid ligament substructure and associated injury patterns can guide the radiologist in defining underlying mechanical derangement, such as that seen in various impingement disorders. In this review article, the MR imaging technique for the deltoid ligament is summarized, and the normal and abnormal MR imaging appearances of various components of the deltoid ligament and associated impingement syndromes are presented.