Intradural cervical herniated nucleus pulposus presentation and management: a case report.

Background: Intradural disc herniations (IDH) are uncommon and can be found in the cervical spine. It is commonly associated with Brown-Sequard syndrome (BSS). The case report describes cervical spine magnetic resonance imaging (MRI) findings that assists in identifying IDH pre-operatively and discusses surgical management. Case Description: This is a case report regarding a 42-year-old obese male who developed atraumatic spontaneous bilateral upper extremity numbness, right upper extremity weakness and right lower extremity weakness. MRI showed a C6-7 herniated nucleus pulposus that focally protruded through the posterior longitudinal ligament with a beak-like projection similar to what has been described in previous reports. Clinical exam revealed an incomplete spinal cord injury (SCI) most consistent with BSS. He underwent anterior cervical discectomy and fusion at the level of C6-7. Intra-operatively, a disc fragment was found to be embedded in the dura. Three months post-operatively, the patient had persistent weakness in his right lower extremity but no longer had any bilateral upper extremity weakness. Conclusions: An anterior cervical decompression and fusion was performed shortly after the patient presented, with adequate neurological recovery after 3 months. Advanced imaging with an MRI could lead to the diagnosis of an IDH and surgical intervention via the anterior approach could facilitate removal of the disc and adequate dura repair.

A report of an intracortical chondroblastoma of the diaphysis in a skeletally mature patient.

Chondroblastomas characteristically occur in skeletally immature patients, and arise within the medullary canal of the epiphysis. We report a rare case of an intracortical chondroblastoma arising in the diaphysis, and occurring in an adult in his 3rd decade of life. Immunohistochemistry results were critical to confirmation of this rare diagnosis, with immunohistochemistry showing S100, DOG1, and H3K36me3 positivity in the neoplastic cells.

Destructive Arthropathy of the Femoral Head.

OBJECTIVES: Destructive arthropathy of the hip refers to noninfectious arthropathy causing extensive femoral head bone destruction. It has been described in the surgical literature using a variety of diagnostic criteria, but it remains a poorly defined entity. METHODS: Cases of destructive arthropathy diagnosed at our institution between July 1, 2015, and December 31, 2019, were identified by a free text search of the radiology database. The medical record of each case was reviewed for possible causes of femoral head destruction, clinical presentation, laboratory values, imaging studies, and pathologic diagnoses. Imaging studies and pathology specimens were retrospectively reviewed. RESULTS: Twenty femoral heads were identified in which there was 25% or greater destruction of the femoral head in the absence of infections, congenital disease, or inflammatory arthritis. Destructive arthropathy was characterized pathologically by fibromyxoid change of the marrow, aggregates of necrotic bone fragments, increased numbers of osteoclasts, increased trabecular destruction, and granuloma-like aggregates. CONCLUSIONS: The histologic findings were distinctive. We postulate that a variety of preexisting conditions set in motion a cascade of tissue factors that led to bone destruction.

A preliminary assessment of intervertebral disc health and pathoanatomy changes observed two years following anterior vertebral body tethering.

PURPOSE: Vertebral body tethering (VBT) has been reported as a safe and effective non-fusion surgical technique for the treatment of adolescent idiopathic scoliosis, but the postoperative health of the bone and soft tissues of the spine following instrumentation remains unknown. We aimed to evaluate pathoanatomy and degenerative changes of the spine in adolescent idiopathic scoliosis patients both prior to and two years following VBT. METHODS: We prospectively enrolled nine patients who underwent VBT for the treatment of progressive adolescent idiopathic scoliosis. All patients received preoperative and two-year postoperative magnetic resonance imaging of their spine; images were assessed for pathoanatomy (e.g. nucleus pulposus positioning and muscle atrophy) and degenerative changes (e.g. Schmorl nodes, endplate oedema, disc degeneration, and osteoarthritis) at each vertebral level between T1 and S1. RESULTS: Four patients (44%) exhibited a shift of the nucleus pulposus from an eccentric position at baseline towards midline at three or more levels, most of which were in the tethered region. Tethering did not affect preexisting fatty atrophy of multifidus. No patients exhibited postoperative Schmorl nodes, endplate oedema, or disc degeneration in either the tethered or untethered regions. Four patients (44%) presented with mild facet osteoarthritis in the lower lumbar spine, which did not change postoperatively. One patient developed moderate facet osteoarthritis at L5-S1. CONCLUSIONS: These preliminary data indicate that VBT may not result in significant degenerative changes in either the intervertebral discs or the posterior facets two years following instrumentation.

Left atrial tumor thrombus with emboli to the brain and distal extremities: A case report.

Cardiac metastases are an uncommon phenomenon associated with neoplasms from a variety of primary sites. Pulmonary involvement often accompanies metastases involving the left atrium or ventricle and clinical presentation may be associated with stroke or emboli involving distal sites. We report a patient who presented acutely to the Emergency Department with symptoms of a cerebrovascular accident and bilateral cold pulseless lower extremities. Computerized Tomographic (CT) angiogram of the chest, abdomen, pelvis and lower extremities disclosed pulmonary veins with large filling defects in the right superior and inferior vessels as well as the left atrium and atrial appendage. Mediastinal and hilar adenopathy was detected. The patient had a history of tonsillar squamous cell carcinoma eighteen months prior. The patient underwent operative intervention with removal of a large left intra-atrial mass, histologic evaluation of which demonstrated groups of malignant squamous cells meshed in fibrin clot. The patient died three days post operatively due to multiple brain infarctions.

Pathology Assessment of Femoral Head Resection Specimens: An Important Quality Assurance Procedure.

CONTEXT.­: Decisions to perform hip arthroplasty rely on both radiographic and clinical findings. Radiologists estimate degree of osteoarthritis (OA) and document other findings. Arthroplasty specimens are sometimes evaluated by pathology. OBJECTIVE.­: To determine the frequency of pathologic changes not recognized clinically. DESIGN.­: Nine hundred fifty-three consecutive femoral head resections performed between January 2015 and June 2018, with recent radiologic and histologic study, were reviewed. We compared severity of OA reported by radiology and pathology. Findings unrecognized radiographically but recorded pathologically, and discrepancies between clinical diagnosis and pathology diagnosis, were tabulated. RESULTS.­: Twenty-one cases of osteomyelitis were diagnosed radiographically or pathologically. Eight discrepancies were present. Fourteen osteomyelitis cases were recognized clinically. Pathology recognized 2 neoplasms missed radiographically. Avascular necrosis was diagnosed on pathology but not radiology in 25 cases, and 35 cases of avascular necrosis were seen radiographically but not pathologically. Osteoarthritis was graded both radiographically and pathologically from 0 to 3. Five hundred ninety-one of 953 cases (62%) were grade 3. Pathologists and radiologists had perfect agreement in 696 of 953 cases (73%). When grade of OA seen at pathology was correlated with surgeon, 2 groups of surgeons were detected: one with a low threshold for performance of hip arthroplasty (23%-28% low-severity OA) and the second with a high threshold (2%-5% low-severity OA). CONCLUSIONS.­: Correlation between radiology and pathology diagnoses is high. Degree of OA present varies significantly between surgeons. Pathology discloses findings not recognized clinically.

Safety and Complications Associated With MRI-Conditional External Fixators in Patients With Tibial Plateau Fractures: A Case Series.

OBJECTIVES: To address the safety of obtaining magnetic resonance imaging (MRI) in patients with temporary knee-spanning external fixators placed for tibial plateau fractures. DESIGN: Institutional Review Board-approved retrospective review. SETTING: Level 1 trauma center. PATIENTS/PARTICIPANTS: Records were reviewed on patients with knee-spanning external fixators applied during staged management of tibial plateau fractures from 2009 to 2015 and who also had an MRI performed. MAIN OUTCOME MEASUREMENTS: Complications associated with the MRI; secondary outcomes were pain scores, narcotic requirements, and fracture healing. RESULTS: A total of 56 patients with 57 fractures were included, and 55 scans (96.5%) were completed without complication. Two scans (3.5%) were stopped prematurely for patient-reported pain and subjective warmth of the external fixator. For all 57 studies, pain scores and narcotic usage were unchanged, and all fractures healed without complication. CONCLUSIONS: Knee-spanning external fixator placement does not preclude MRI for patients with tibial plateau fractures. MRIs can be safely performed on patients with external fixators if patients are educated before imaging. Even in the small percentage of patients who experienced discomfort, there were no long-term complications. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The Use of Fluoroscopy During Direct Anterior Hip Arthroplasty: Powerful or Misleading?

BACKGROUND: Direct anterior approach total hip arthroplasty (THA) with fluoroscopic assistance is growing in popularity. Variables such as pelvic tilt, c-arm technique, and patient positioning can affect the perceived fluoroscopic view. This study evaluates the effect of these variables on the position of the acetabular component. METHODS: Forty-one hips in 40 patients undergoing direct anterior arthroplasty THA with fluoroscopic assistance underwent routine postoperative radiographs and postoperative pelvic computed tomography scan. The acetabular component position as defined by a 3-dimensional reconstruction was compared to the surgeon's intraoperative perception of the component's position and compared to routine postoperative plain radiograph measurements. RESULTS: Although fluoroscopy was used to create an anteroposterior pelvic radiograph utilizing the coccyx to pubis symphysis distance, a 3D reconstruction created in the same pelvic orientation as the fluoroscopic images confirmed that 39/41 hips were placed with unrecognized excess of anteversion and inclination secondary to imaging the pelvis in extension. CONCLUSION: Intraoperative imaging during supine direct anterior arthroplasty THA confirms appropriate component placement. Pelvic tilt can greatly affect the perceived position of the acetabular component and cannot be accurately compensated for by assessing the relationship between the coccyx and pubic symphysis due to morphologic variation and orientation. We recommend positioning the c-arm so that the size and shape of the obturator foramen matches the standing preoperative anteroposterior pelvis image. This technique allows for the native standing pelvic tilt to be accounted for intraoperatively and will result in the least variation in intraoperative and postoperative standing acetabular component orientation.

Radiologic and Histologic Evaluation of Proximal Bicep Pathology in Patients With Chronic Biceps Tendinopathy Undergoing Open Subpectoral Biceps Tenodesis.

PURPOSE: To correlate preoperative magnetic resonance imaging (MRI) and intraoperative anatomic findings within the proximal long head biceps tendon to histologic evaluation of 3 separate zones of the tendon in patients with chronic biceps tendinopathy. METHODS: Sixteen patients with chronic biceps tendinopathy were treated with open subpectoral biceps tenodesis. Preoperative MRI tendon grading was as follows: normal tendon, increased signal, tendon splitting, incomplete/complete tear. The removed portion of the biceps tendon was split into 3 segments: zone 1, 0-3.5 cm from the labral insertion; zone 2, 3.5-6.5 cm; and zone 3, 6.5-9 cm, and was histologically evaluated using the Bonar score. Tenosynovium adjacent to the tendon was assessed histologically using the Osteoarthritis Research Society International score. CD31, CD3, and CD79a immunohistochemistries were conducted to determine vascularization, T-cell infiltrates, and B-cell infiltrates, respectively. Analysis of variance and Pearson correlations were performed for statistical analysis. RESULTS: Preoperative MRI showed no significant differences in tendon appearance between zones 1-3. Intraoperative findings included nonspecific degenerative SLAP tears or mild/moderate biceps tenosynovitis in all cases. Significantly (P < .001) higher Bonar scores were noted for tendon in zones 1 (7.9 ± 1.8) and 2 (7.3 ± 1.5) compared with zone 3 (5.0 ± 1.1). Cell morphology scores in zone 1 (1.9 ± 0.4) and zone 2 (1.5 ± 0.6) were significantly higher than that in zone 3 (0.8 ± 0.3) (P < .05). Inflammatory tenosynovium showed weak correlation with tendon changes in zone 1 (r = 0.08), zone 2 (r = 0.03), or zone 3 (r = 0.1). CONCLUSIONS: In patients with chronic long head biceps tendinopathy who underwent open subpectoral tenodesis, MRI and intraoperative assessment did not show significant structural abnormalities within the tendon despite significant histopathologic changes. Severity of tendon histopathology was more pronounced in the proximal and mid-portions of the tendon. CLINICAL RELEVANCE: Proximal versus distal biceps tenodesis is a subject of frequent debate. This study contributes to the ongoing evaluation of the characteristics of the proximal biceps in this type of pathologic condition.

Findings Associated With Knee Pathology on MRI in Patients Without Osteoarthritis.

INTRODUCTION: We conducted a retrospective study in patients with minimal or no radiographically evident knee osteoarthritis to determine whether presenting signs and symptoms were predictive of knee pathology that was evident on MRI and could be treated with nonarthroplasty knee surgery or could alter nonsurgical treatment. METHODS: We reviewed records of patients for whom sports medicine orthopaedic surgeons had ordered an MRI of the knee. Univariate analysis identified factors that were associated with positive MRI findings (eg, surgically treatable lesion, meniscal tear) or a finding that could alter treatment. We used multivariate logistic regression to determine independent predictors of evidence of pathology on MRI. RESULTS: Of the 434 patients in the study, 281 (64.7%) had evidence of knee pathology on MRI. Acute injury, effusion, and ligamentous instability were among the independent predictors of positive MRI results. Patients with evidence of knee pathology on MRI were more likely to have undergone surgery. DISCUSSION: Specific aspects of patient history and physical examination are associated with evidence of knee pathology on MRI. CONCLUSIONS: In patients without osteoarthritis, positive findings on knee MRI could be associated with a number of presenting signs and symptoms, and this information could aid physicians in deciding which patients should undergo knee MRIs. Additional prospective research is needed to validate the relationships discovered in our study. LEVEL OF EVIDENCE: Level III retrospective study.

Osteochondroma mimicking meningioma: case report and literature update.

We report a case of an osteochondroma in a 47-year-old woman presenting with a 2-month history of thoracic back pain that radiated down her left arm. Based on imaging features, the osteochondroma was initially thought to represent a calcified meningioma. The unusual features of the case include the location of the tumor, patient age, the erosion of the vertebra, and the confusing neuroradiological features. We review reported cases in which a solitary costal osteochondroma impinges on the neural foramina or central spinal canal and we discuss reasons for the misdiagnosis in our case.

Local anesthetic injection deep to the fascia iliaca at the level of the inguinal ligament: the pattern of distribution and effects on the obturator nerve.

STUDY OBJECTIVE: The femoral, lateral femoral cutaneous, and obturator nerves (ONs) can reportedly be blocked using a single-injection deep to the fascia iliaca (FI) at the level of the inguinal ligament. Two commonly used methods (the FI compartment and 3-in-1 blocks) have produced inconsistent results with respect to local anesthetic distribution and effect on the ON. To date, no study of either method has been performed using advanced imaging techniques to document both needle placement and local anesthetic distribution. We report the outcome of a series of 3-in-1 and FI blocks performed using ultrasound to guide needle position and magnetic resonance imaging (MRI) to define local anesthetic distribution. DESIGN: Patients were prospectively studied, and images were interpreted using a randomized and blinded protocol. SETTING: The study was performed in the perioperative area of an academic orthopedic specialty hospital. PATIENTS: Ten patients (ASA 1-2) having anterior cruciate ligament reconstruction received either 3-in-1 or FI compartment blocks for postoperative analgesia using the surface landmarks described for these techniques. INTERVENTIONS: Ultrasound was used to position the injecting needle immediately deep to the FI. Local anesthetic distribution was studied using MRI. MEASUREMENTS: Patients were examined for motor and/or sensory function of the femoral, obturator, and lateral femoral cutaneous nerves. Magnetic resonance imaging was used to document the limits of injectate distribution. MAIN RESULTS: Magnetic resonance imaging showed distribution of injectate over the surface of the iliacus and psoas muscles to the level of the retroperitoneum. No patient showed medial extension of injectate to the ON. At the level of the inguinal ligament, injectate extended laterally toward the anterior superior iliac spine and medially to the femoral vein. All patients had significant weakness with extension of the knee and sensory loss over the anterior, lateral, and medial thigh. No patient demonstrated decreased hip adductor strength. CONCLUSIONS: Ultrasound and MRI show consistent superior extension of local anesthetic to the level of the retroperitoneum for both techniques. There was reliable clinical effect on the femoral and lateral femoral cutaneous nerves. However, none of the injections produced evidence of ON block either at the level of the retroperitoneum or the inguinal ligament.

Physician provider type influences utilization and diagnostic utility of magnetic resonance imaging of the knee.

BACKGROUND: Magnetic resonance imaging of the knee is expensive and is neither needed nor useful for all patients presenting with knee pain. Our objective was to determine the completeness of evaluation prior to ordering magnetic resonance imaging of the knee correlated to the ordering providers' postgraduate medical training and the rate of positive findings on the subsequent magnetic resonance imaging. METHODS: Six hundred consecutive knee magnetic resonance images were reviewed, including 200 consecutive knee magnetic resonance imaging examinations from each of three provider types: orthopaedic surgeons, non-surgical physicians with sports medicine training, and primary care providers. Positive findings on magnetic resonance imaging were recorded as well as a history of present illness, a physical examination, and radiographs made prior to ordering magnetic resonance imaging of the knee. Patient and injury factors were recorded. Differences in patient factors, evaluation before magnetic resonance imaging, and positive findings were examined. A modified Poisson regression approach was used to determine predictors of a proper evaluation before magnetic resonance imaging and positive findings on knee magnetic resonance imaging. RESULTS: Orthopaedists and non-surgical sports physicians were significantly more likely to document a physical examination, to evaluate radiographs made prior to ordering a magnetic resonance image, and to identify positive findings on the magnetic resonance image (all p < 0.001). In multivariate models, orthopaedists were more likely to document a history of present illness (relative risk, 1.05; p = 0.043). Compared with primary care physicians, a physical examination was more likely to be documented by both non-surgical sports medicine physicians (relative risk, 1.61; p < 0.001) and orthopaedists (relative risk, 1.60; p < 0.001) and positive magnetic resonance imaging findings were more likely to be found by non-surgical sports medicine physicians (relative risk, 1.41; p = 0.012) and by orthopaedists (relative risk, 1.44, p = 0.009). Other independent predictors of a magnetic resonance imaging study with positive findings were the presence of an acute injury by history (relative risk, 2.04; p < 0.001) and younger age (relative risk, 0.99; p = 0.021). CONCLUSIONS: Orthopaedists and non-surgical sports physicians are more likely to perform and to document a complete evaluation prior to ordering a knee magnetic resonance image with a positive finding. More musculoskeletal training may be useful to enable primary care physicians to use magnetic resonance imaging of the knee in a more efficient manner.

Diagnostic accuracy and clinical utility of biopsy in musculoskeletal lesions: a comparison of fine-needle aspiration, core, and open biopsy techniques.

Selection of biopsy technique for musculoskeletal lesions is complex. Fine-needle aspiration (FNA) is uncommonly used due to concerns regarding accuracy. We compared diagnostic accuracy of FNA, core, and open biopsy in a series of musculoskeletal lesions. Records of the University of Utah were searched for biopsy and resection specimens of musculoskeletal lesions. Results of corresponding imaging studies were obtained. Biopsy and FNA diagnoses were correlated with resection diagnoses. For each technique, diagnostic accuracy, utility, and frequency of subsequent biopsy were calculated. Open biopsy had the highest diagnostic accuracy (89%) followed by FNA (82%) and core biopsy (78%). Clinically significant errors occurred with all methods. The likelihood of an open biopsy being performed was affected by prior performance of an FNA or core biopsy and by diagnostic imaging and FNA results.

Characterization of synovial sarcoma calcification.

OBJECTIVE: The objective of our study was to characterize patterns of calcifications in synovial sarcoma. CONCLUSION: The presence of fine, stippled calcifications in a soft-tissue mass should raise suspicion for synovial sarcoma. These calcifications can coalesce to a deposit that mimics hydroxyapatite deposition disease or soft-tissue osteosarcoma. Spicules of calcification were a less common finding in our series; the appearance of spicules in synovial sarcomas overlaps with that of other soft-tissue sarcomas such as soft-tissue osteosarcoma and liposarcoma.

Fine-needle aspiration diagnosis of an intraosseous amyloidoma.

Fine-needle aspiration (FNA) is frequently used as the initial diagnostic procedure for the investigation of bone and soft tissue masses. The majority of the lesions detected will represent metastatic carcinoma. Amyloid is a rare cause of a bone mass, with less than 15 published reports describing amyloid deposition within bone. The majority of reported cases involve the vertebral column. We report the finding of a massive amyloidoma of the iliac wing in a 46-year-old man. FNA smears and cell block preparations demonstrated fragments of waxy acellular material misinterpreted as necrotic debris. Subsequent open biopsy established the diagnosis of amyloid with congo red staining demonstrating apple green birefringence. Subsequent workup disclosed the patient to have anemia, hypogammaglobulinemia and trace monoclonal light chain gammopathy. Bone marrow examination revealed CD138a positive lambda restricted plasma cells consistent with plasma cell dyscrasia. Careful attention to the staining characteristics of amyloid in FNA derived material should allow the diagnosis of amyloidoma.

Deltoid ligament abnormalities in chronic lateral ankle instability.

BACKGROUND: Treatment of patients with repeated ankle sprains and chronic lateral ankle instability tends to focus on the lateral collateral ligaments. We reviewed records to ascertain the prevalence of abnormalities of the deltoid ligament in this population. METHODS: Retrospective review of MR images and surgical reports was performed for all patients during a 3-year period that underwent surgical treatment of chronic ankle instability at a single institution. Forty-seven ankles (46 patients) met inclusion criteria. None had medial ankle pain. RESULTS: On MRI, all patients had anterior talofibular ligament tear, plus injury to one or more additional ligaments. Ninety-one percent had injury of calcaneofibular ligament. Injury to the posterior talofibular ligament was less common (49%). Deltoid ligament injuries were seen in 72% of cases (23% superficial deltoid only, 6% deep deltoid only, 43% both superficial and deep components). Of patients with injury to the superficial deltoid, 32% had an intact deep deltoid ligament. MRI correlated well to surgical findings. CONCLUSION: Deltoid ligament injuries were common in patients with lateral ankle instability who underwent reconstruction.

Proximal radial drift following radial head resection.

BACKGROUND: Proximal radial migration is a well-documented phenomenon after radial head resection, but there have been no studies evaluating other planes of proximal radial stump drift after resection. The purpose of this study is to evaluate the anatomic position of the radial stump in relation to the capitellum after radial head resection, and determine the factors affecting this position and long-term functional outcomes. METHODS: Thirteen patients who had undergone radial head resection for a variety of injury patterns were identified and evaluated at a mean of 72 months postoperative. Each patient underwent a physical exam and outcome questionnaire evaluation (Disabilities of the Arm, Shoulder, and Hand [DASH] questionnaire, Mayo Elbow Performance Score [MEPS], and pain Visual Analog Scales [VAS] questionnaire). Anterior-posterior (AP) and lateral radiographs of the elbow were also performed. RESULTS: The proximal radius resection length was an average of 18 mm (range, 11.1-31.9) compared to the nonoperative side. The proximal radial stump was determined to have significant migration both medially (P = .01) and posteriorly (P = .002) as compared to the opposite side as determined on the AP and lateral radiographs, respectively. Greater than 2 cm of proximal radial resection was associated with greater posterior drift (P = .03). Poorer MEPS were only correlated with an initial dislocation injury pattern (P = .02). CONCLUSION: Radial head resection for fracture often leads to posterior and medial drift of the proximal radial stump, resulting in nonanatomic alignment with the capitellum. Increased resection greater than 2 cm resulted in larger amounts of drifting. Only a dislocation injury pattern was associated with worse functional outcomes.

Current concepts in the evaluation of multiple myeloma with MR imaging and FDG PET/CT.

Multiple myeloma is a heterogeneous group of plasma cell neoplasms that primarily involve bone marrow but also may occur in the soft tissue. Although the disease varies in its manifestations and its course, it is eventually fatal in all cases. Over the past 2 decades, significant advances have been made in our understanding of the genetics and pathogenesis of multiple myeloma and in its treatment. The use of magnetic resonance (MR) imaging and fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) with computed tomography (CT) has improved sensitivity for the detection of this disease. PET aids in the identification of active multiple myeloma on the basis of FDG uptake, and MR imaging helps identify multiple myeloma from its infiltration of normal fat within the bone marrow, which occurs in characteristic patterns that correlate with the disease stage. The increased sensitivity of these advanced cross-sectional imaging techniques has led to further refinement of the classic Durie and Salmon staging system. In addition, these imaging techniques allow a more reliable assessment of the disease response to treatment with current regimens, which may include autologous stem cell transplantation as well as various medications. In lesions that respond to chemotherapeutic agents, the replacement of previously infiltrated marrow by fat is seen at MR imaging and decreased FDG uptake is seen at FDG PET; however, a lengthy and intensive regimen may be necessary before the MR imaging appearance of marrow normalizes. Lytic lesions seen at CT almost always persist even after successful treatment. To provide an accurate assessment, radiologists must be familiar not only with the appearances of multiple myeloma and its mimics but also with common treatment-related findings.