Computed Tomography Diagnosis of Patent Ductus Arteriosus Endarteritis and Septic Pulmonary Embolism

No abstract available.

Temporary Semi-Jailing Technique for Coil Embolization of Wide-Neck Aneurysm with Small Caliber Parent Artery Following Incomplete Clipping

The authors describe the use of a self-expandable stent in a temporary deployment for treatment of a very wide-neck A1 segment of anterior cerebral artery (ACA) aneurysm following incomplete clipping. A 39-year-old hypertensive man presenting with seizure-like movement underwent computed tomography, which showed acute subarachnoid hemorrhage and an A1 segment of ACA aneurysm with superior and inferior projection. He underwent surgical clipping of the aneurysm, but superior and posterior portion of wide-neck aneurysm remained. We decided to treat the remnant aneurysm using an endovascular modality. After selection of the aneurysm, coil packing was performed assisted by the temporary semi-jailing technique. The Enterprise stent (Cordis Neurovascular, Miami, FL, USA) was deployed and recaptured repeatedly for angiography to ensure safety of the small caliber parent artery. Successful semi-deployment and recapture of the stent allowed subtotal coil occlusion of the aneurysm with good anatomic and clinical results. No complications were encountered. The stent could be recaptured up to the point where the proximal end of the stent marker was aligned with distal marker band of the microcatheter, approximately 70% of the stent length. The temporary semi-jailing technique is feasible for wide-neck aneurysm with small caliber parent artery.

The Ratio of Descending Aortic Enhancement to Main Pulmonary Artery Enhancement Measured on Pulmonary CT Angiography as a Finding to Predict Poor Outcome in Patients with Massive or Submassive Pulmonary Embolism / 결핵및호흡기질환

BACKGROUND: The purpose of this study was to evaluate whether measuring the ratio of descending aortic enhancement (DAE) to main pulmonary artery enhancement (MPAE) on pulmonary computed tomography angiography (PCTA) can predict poor outcome in patients with acute massive or submassive pulmonary embolism (PE). METHODS: We retrospectively, reviewed computed tomgraphy findings and charts of 37 patients with acute PE and right ventricular dysfunction. We divided the enrolled patients into 3 groups; group Ia (n=8), comprised of patients with major adverse event (MAE); group Ib (n=5), consisted of those with PE-related MAE; and group II (n=29), those without MAE. We analyzed the right ventricular diameter (RVD)/left ventricular diameter (LVD) and DAE/MPAE on PCTA. RESULTS: For observer 1, RVD/LVD in group Ia (1.9+/-0.36 vs. 1.44+/-0.38, p=0.009) and group Ib (1.87+/-0.37 vs. 1.44+/-0.38, p=0.044) were significantly higher than that of group II. For observer 2, RVD/LVD in group Ia (1.71+/-0.18 vs. 1.41+/-0.47, p=0.027) was significantly greater than that of group II, but RVD/LVD of group Ib was not (1.68+/-0.2 vs. 1.41+/-0.47, p=0.093). For both observers, there was a significant difference of DAE/MPAE between group Ib and group II (0.32+/-0.15 vs. 0.64+/-0.24, p=0.005; 0.34+/-0.16 vs. 0.64+/-0.22, p=0.004), but no significant difference of DAE/MPAE between group Ia and group II (0.51+/-0.3 vs. 0.64+/-0.24, p=0.268; 0.53+/-0.29 vs. 0.64+/-0.22, p=0.302). Intra-class correlation coefficient (ICC) for the measurement of DAE/MPAE (ICC=0.97) was higher than that of RVD/LVD (ICC=0.74). CONCLUSION: DAE/MPAE measured on PCTA may predict PE-related poor outcomes in patients with massive or submassive PE with an excellent inter-observer agreement.

Correlation Between Vertebral Marrow Fat Fraction Measured Using Dixon Quantitative Chemical Shift MRI and BMD Value on Dual-energy X-ray Absorptiometry

PURPOSE: The purpose of this study was to determine whether there is a significant correlation between vertebral marrow fat fraction measured using Dixon quantitative chemical shift MRI (QCSI) and BMD on dual-energy X-ray absorptiometry (DXA). MATERIALS AND METHODS: This retrospective study included 68 healthy individuals [mean age, 50.7 years; range, 25-76; male/female (M/F) = 36/32] who underwent DXA of the L-spine and whole body MRI including QCSI of the L-spine and chemical shift MRI of the liver. The enrolled individuals were divided into subgroups according to sex and T-score [i.e., normal bone density (M/F=27/23) and osteopenia (M/F=9/9)]. Vertebral marrow (Dixon QCSI, TR/TE 10.2/4.8 ms) and hepatic fat fractions (chemical shift technique, TR/TE 110/4.9 and 2.2 ms) were calculated on MRI. We evaluated whether there were significant differences in age, body mass index (BMI), vertebral marrow fat fraction, or hepatic fat fraction among the subgroups. Whether or not the participant had reached menopause was also evaluated in females. The correlations among variables (i.e., age, BMI, vertebral marrow and hepatic fat fractions, BMD) were evaluated using Spearman's correlation method. RESULTS: There were no significant differences in age, BMI, or vertebral marrow and hepatic fat fractions between the two male subgroups (normal bone density vs. osteopenia). In female subjects, mean age in the osteopenic subgroup was greater than that in the normal subgroup (p=0.01). Presence of menopause was more common in the osteopenic subgroup [77.8% (7/9)] than the normal subgroup [26.1% (6/23), p<0.05]. The other variables showed no significant difference between female subgroups. The only significant correlation with marrow fat fraction after partial correlation analysis was that with age in the female subjects (r=0.43, p<0.05). CONCLUSION: The vertebral marrow fat fraction calculated using the Dixon QCSI does not precisely reflect the mild decrease in BMD for either sex.

Current Concepts in Cardiac CT Angiography for Patients With Acute Chest Pain

This article presents specific examples of delayed diagnosis of acute coronary syndrome, acute aortic dissection, and pulmonary embolism resulting from evaluating patients with nonspecific acute chest pain who did not undergo immediate dedicated coronary CT angiography (CTA) or triple rule-out protocol (TRO). These concrete examples of delayed diagnosis may advance the concept of using cardiac CTA (i.e., dedicated coronary CTA versus TRO) to triage patients with nonspecific acute chest pain. This article also provides an overall understanding of how to choose the most appropriate examination based on the specific clinical situation in the emergency department (i.e., dedicated coronary CTA versus TRO versus dedicated pulmonary or aortic CTA), how to interpret the CTA results, and the pros and cons of biphasic versus triphasic administration of intravenous contrast material during TRO examination. A precise understanding of various cardiac CTA protocols will improve the diagnostic performance of radiologists while minimizing hazards related to radiation exposure and contrast use.

Solitary Necrotic Nodule of the Liver Mimicking Metastasis in Patient with Early Gastric Cancer: 3T MRI and PET/CT Findings

Solitary necrotic nodule (SNN) of the liver is a very uncommon benign lesion, and it is detected incidentally as a rule. It is important to differentiate SNN radiologically from various single hepatic nodules because SNN mimics hepatic metastasis, especially in staging work up of known primary malignancy. The reported imaging findings of SNN are well-defined nodule without enhancement or with subtle peripheral enhancement. There has been no report about the target-like SNN of the liver and about the imaging finding of 3T magnetic resonance imaging and positron emission tomography. We report a case of targetlike SNN of the liver, mimicking hepatic metastasis, with findings of various imaging modalities and try to find a cause of this nodule according to the pathologic and literature review.

US Findings of Biceps Tendinitis: Cross Sectional Area Measurements of Long Head of Biceps Brachii

PURPOSE: The purpose of this study was to describe typical sonographic findings in patients with biceps tendinitis. MATERIALS AND METHODS: Seventy five patients who had been clinically diagnosed with biceps tendinitis were included. Of the 75, 37 were male, 38 were female, and their mean age was 56 +/- 9.74. The patients complained of shoulder pain and ultrasonography was performed for bilateral shoulders in all patients. The cross sectional area of the biceps tendon was measured. The status of fluid collection around the biceps tendon and accompanying rotator cuff disease were also investigated. RESULTS: The cross sectional areas of the diseased biceps tendon were 0.18 +/- 0.09 cm2 (range: 0.07-0.42), and the areas of the normal side was 0.11 +/- 0.05 cm2 (0.03-0.24). The cross sectional area of the diseased biceps tendon was 0.075 +/- 0.062 cm2 greater, on average, than the uninvolved site (p < 0.01). Thirty six patients (48%) had fluid collection around the inflamed biceps tendon, and 30 patients had accompanied rotator cuff disease. CONCLUSIONS: During US examination of the shoulder in patients complaining of shoulder pain, if the cross sectional area of the biceps tendon in the painful shoulder is asymmetrically and larger than the contralateral tendon, biceps tendonitis is suggested.

Clinical Variables Indicating Cervical Abscess in Adult Patients Diagnosed with Deep Neck Infection

PURPOSE: We evaluated a method to distinguish group A (abscess) from group B (cellulitis, pharyngitis, tonsillitis, epiglottis) through clinical variables in patients with a deep neck infection. METHODS: This was a retrospective chart review study consisting of the evaluation of CT scans or surgical diagnoses on adult patients (18 or more years of age). CT scans were reviewed by a radiologist. We evaluated several clinical variables in order to distinguish group A from group B. We also evaluated the ability of these clinical variables to distinguish group A from group B by a receiver operating characteristic curve. RESULTS: Sixty-three patients were enrolled in this study. Several clinical variables (swelling, odynophagia, tenderness, trismus, age>50years) differed between group A and group B. A AUC which was obtained by adding the number of variables (swelling, odynophagia, tenderness, trismus, age>50years) was 0.87 (p50, swelling, odynophagia, tenderness, trismus) were able to distinguish group A from group B.

A Case of Transient Radiographic Progression during Treatment of Pulmonary Tuberculosis: Early CT Findings / 결핵및호흡기질환

Early CT findings of transient radiographic progression (TRP) during treatment of active pulmonary tuberculosis including subpleural, interlobular or intralobular septal thickening and micronodules are shown in the present case. Late CT findings of TRP are subpleural, enhancing nodular infiltration with internal low attenuation. These CT features accompanied by a lack of clinical worsening in young patients taking antituberculous medication due to pulmonary tuberculosis can help to differentiate TRP from other disease entities.

Contrast Extravasation into an Acute Spontaneous Intracerebral Hematoma: Multidetector CT Angiographic Findings and Clinical Implications

PURPOSE: The purpose of this study was to evaluate multidetector row CT (MDCT) angiographic findings and their clinical significance for contrast extravasation into a spontaneous intracerebral hematoma (ICH). MATERIALS AND METHODS: MDCT angiographic studies and clinical records of 115 patients with spontaneous ICH were retrospectively reviewed. Cases were divided into two groups according to the presence or absence of contrast extravasation. The cases in the two groups were compared to determine the differences in radiological and clinical findings. The contrast extravasation group was divided into two subgroups according to radiological findings as follows: single or multiple dot-like contrast extravasation (Type A) and beaded-tubular (with or without dot-like extravasation) contrast extravasation (Type B). RESULTS: Contrast extravasation was seen in 38 patients (33%). It was associated with a larger hematoma volume, more frequent intraventricular hemorrhage (IVH) and subarachnoid hemorrhage (SAH), a shorter time interval from onset to the time of the CT scan, lower Glasgow coma scale (GCS), and a higher mortality rate. Type A and B contrast extravasation were observed in 16 (42%) and 22 (58%) patients, respectively. The rate of IVH and the clinical outcome of patients with Type B showed a significant correlation. CONCLUSION: Two types of contrast extravasation into an ICH show a significant difference in the rate of IVH and in clinical outcome. Detecting the presence of contrast extravasation and classifying them according to the morphologic patterns are important in predicting a prognosis.

CT Findings Related to Negative Results of Sputum Smear in Patients with Active Pulmonary Tuberculosis having Multiple Cavities / 결핵및호흡기질환

BACKGROUND: This study evaluated which CT findings could be used to predict the negative results of a sputum smear in patients with active pulmonary tuberculosis and multiple cavities. METHODS: Thirty-eight patients with active pulmonary tuberculosis and multiple cavities on CT were classified into 2 groups: smear-positive (n = 30) and -negative (n = 8). The CT findings were reviewed retrospectively. The maximum internal diameter of the largest cavity, the number of the cavities and lobes with cavities, and the characteristics of the associated findings such as consolidation, ground glass opacity, micronodules and nodule were accessed. The number of cavities above 20 mm in the maximum internal diameter and a necrotizing pneumonia-like pattern were also evaluated. RESULT: The maximum internal diameter and number of cavities was 32.23 +/- 17.66 mm and 15.50 +/- 11.12 mm (p = 0.0042), and 5.53 +/- 3.17 and 2.43 +/- 1.13 (p = 0.0002) in the smear-positive and -negative group, respectively. Three or more cavities were observed at 76.7% and 12.5% in the smear-positive and -negative group, respectively (p 20 mm in the maximum internal diameter were 100%, 62.5%, 90.9%, and 100%, respectively. CONCLUSION: Two cavities 20 mm or less in the maximum internal diameter without consolidation on CT might be associated with a negative result of the sputum smear in patients with active pulmonary tuberculosis and multiple cavities.

Differences in CT Findings According to Sputum Smear Results in Patients with Active Pulmonary Tuberculosis Having a Single Cavity / 결핵및호흡기질환

Background: The purpose of this study was to evaluate the differences in CT findings according to sputum smear- positive or -negative results in patients with active pulmonary tuberculosis having a single cavity. Methods: A total of 32 patients with active pulmonary tuberculosis having a single cavity on CT were classified into two groups: smear-positive (n=19) and smear-negative (n=13). The CT findings were reviewed retrospectively. The presence of consolidation, the number of lobes showing consolidation, ground-glass opacity, micronodules and nodule, the maximum diameter of the cavity, and the shape and maximum thickness of the cavity wall were assessed. Result: The maximum diameter of the cavity was 33.84 +/- 13.65 mm and 27.08 +/- 9.04 mm in the smear-positive and -negative groups, respectively (p>0.05). The amount of consolidation and the number of lobes with consolidation were found to be 89.5% and 30.8% (p=0.01) and 1.37 +/- 0.90 and 0.31 +/- 0.48 (p=0.0002) in the smear-positive and -negative groups, respectively. Consolidations in two or more lobes were only noted in 31.6% of in the sputum smear- positive group (p< 0.05). There were no other significant differences between the two groups. The sensitivity, specificity, positive and negative predictive values for the presence of consolidation were 89.5%, 69.2%, 73.9%, and 81.8%, respectively. Conclusion: While the absence of consolidation on CT may be associated with sputum smear-negative results in patients with active pulmonary tuberculosis having a single cavity, the presence of consolidation in two or more lobes on CT may be associated with spear-positive results in these patients.

Relationship between Pleural Adenosine Deaminase Level and Patterns of Pleural Enhancement in Patients with a Tuberculous Pleural Effusion on CT Scan / 결핵및호흡기질환

Background: This study examined the relationship between the pleural adenosine deaminase (ADA) level and the patterns of pleural enhancement in patients with a tuberculous pleural effusion (TPE) shown on a CT scan. Methods: The charts and CT findings of 44 patients with TPE from February 2002 to October 2006 were reviesed retrospectively. A diagnosis of TPE was made by the pleural ADA level with a follow-up (24/44), sputum smear or culture of sputum (16/44), pleural fluid culture (3/44) or pleural biopsy (1/44). The patients were divided into two groups according to the ADA level(Group I [n=12]: 40-70, Group II [n=32]: >70 U/L). The presence or absence, maximal thickness and patterns of pleural enhancement were analyzed. The pattern of pleural enhancement was classified into diffuse or focal, smooth or irregular and interrupted or continuous. The difference in CT findings between groups I and group II were analyzed using an unpaired T test, Chi-square test and Z test. Results: All 44 patients showed diffuse pleural enhancement on the CT scans. The maximal pleural thickness of groups I and II was 1.83 +/- 1.03 mm (1-4 mm) and 3.63 +/- 1.78 mm (1-8 mm), respectively (p =0.0002). Pleural thickening > or = 5 mm was only demonstrated in 31.3% of patients in group II (10/32). Diffuse interrupted pleural thickening was noted in 91.7% (11/12) of patients in group I and 62.5% (20/32) in group II, respectively. Diffuse continuous pleural thickening was observed in 8.3% (1/12) of patients in group I and 37.5% (12/32) in group II, respectively (p=0.0748). Conclusion: Pleural thickening > or = 5 mm on the contrast enhanced CT is rare in patients with lymphocyte-dominant TPE in whom the pleural ADA level is between 40-70 U/L.

Intradural Extramedullary Capillary Hemangioma with Long Segment of Transient Cord Edema: A Case Report

We present a case of intradural extramedullary capillary hemangioma of the thoracic spine with a long segment of transient cord edema. Spinal capillary hemangiomas are extremely rare vascular tumors and only a few cases have been reported. On the MR images, the mass showed hypointensity on the T1-weighted images, hyperintensity on the T2-weighted images relative to the spinal cord, and strong homogeneous enhancement on the contrast-enhanced T1-weighted images. The T2-weighted images showed a long segment of ill-defined hyperintense area in the spinal cord which was completely resolved after surgery.

Diffusion-Weighted MR Imaging in Acute Wernicke's Encephalopathy Associated with Pseudomembranous Colitis: A Case Report and Review of the Literature

Wernicke's encephalopathy is a common complication of thiamine deficiency among chronic alcoholics. However, there have been few reports about MR imaging findings, including the diffusion-weighted changes of this neurologic disorder, in nonalcoholic patients. We present here a rare case of acute Wernicke's encephalopathy that developed in a patient who received prolonged total parenteral nutrition for his pseudomembranous colitis. The MR imaging, including the diffusion-weighted imaging, was performed at the onset of disease and during follow-up. The diagnosis was made by the characteristic MR imaging findings and it was supported by the clinical features. The initial and follow-up MR imaging findings with diffusion-weighted imaging changes are described and correlated with the clinical status.

Comparison of the CT and Pathologic Findings of Pulmonary Fat Embolism Induced by Triolein and Oleic Acid in Rabbits

PURPOSE: The aim of this study was to evaluate the CT findings of pulmonary fat embolism syndrome that was induced by triolein and oleic acid, along with its pathologic correlation. MATERIALS AND METHODS: 16 rabbits were included in this study. The rabbits in group I (n=8) were embolized with 0.2 mL triolein and the rabbits of group II (n=8) were embolized with 0.2 mL oleic acid through ear veins. HRCT scans were done prior to embolization and at 0.5, 4, 24, 48 and 72 hours post-embolization. The pathologic correlations were determined at 0.5, 24, 48 and 72 hours. RESULTS: At 24 hours, one group I rabbit showed abnormal CT findings that were composed of several 2-3 mm nodules and multiple ill-defined peripheral ground glass opacities. The pathologic finding of this rabbit at 48 hours was mainly intraarveolar edema. All the group II rabbits (n=8/8) showed ill-defined bilateral and peripheral ground glass opacities with (n=6/8) or without consolidations (n=2/8) on the 0.5 hour CT. All the rabbits (n=7/7) showed that the new ground glass opacities and ground glass opacities noted on the 0.5 hour CT were changed into consolidation. The margins of the ground glass opacities and consolidations were more sharpened on the 24 hours CT. All 6 rabbits (n=6/6) showed consolidations without ground glass opacities and the margins of the consolidations were more sharpened on the 48 hours CT. There was no significant interval change on the 72 hours CT. The pathologic findings of ground glass opacities were interstitial edema or mild intraalveolar edema. The pathologic findings of consolidation were intraalveolar edema, hemorrhage and coagulation necrosis. CONCLUSION: The CT findings after fat embolization using triolein and oleic acid were ill-defined peripheral ground glass opacities with/without consolidations. These findings occurred in only one triolein group with the time lag, but these findings were immediately and extensively seen in all group II rabbits. These CT findings may be important for making a diagnosis of pulmonary fat embolism syndrome.

Effect of High Dose Steroids on Oleic Acid-induced Lung Injury in Rabbits: CT Findings

PURPOSE: The purpose of this study is to evaluate the therapeutic efficacy, on the basis of CT findings, of high dose methyl prednisolone for treating acute lung injury that was induced by oleic acid injection. MATERIALS AND METHODS: A total of 30 healthy rabbits (1.8-2.2 kg) were included in this study. Group I included 10 rabbits in which 0.2 mL oleic acid was injected through their ear veins. Group IIa included 10 rabbits in which 30 mg/kg methyl prednisolone and 0.2 mL oleic acid were intravenously injected at the same time. Group IIb included 5 rabbits in which 30 mg/kg methyl prednisolone was injected 6 hours prior to the 0.2 mL oleic acid intravenous injection. The other 5 rabbits (Group III) were injected intravenously with 30 mg/kg methyl prednisolone without the oleic acid. After that, 30 mg/kg methyl prednisolone per every 12 hours was injected in the non-sacrificed rabbits of Group II and Group III. Nonenhanced Chest CT scans were performed prior to and 30 minutes, 4 hours, 24 hours, 48 hours, and 72 hours after the intravenous injection of oleic acid or methyl prednisolone. We randomly sacrificed one rabbit of groups I, II and III 30 minutes, 4 hours, 24 hours, 48 hours and 72 hours after CT scanning. The distribution, extent, and pattern of the lesions on the CT scan were analyzed. The analyzed pattern of the lesions was ground glass attenuation, consolidation and interstitial thickening. Pathologic correlation was then done. RESULTS: The main CT findings of Group I were peripheral, wedge shaped, ill-defined ground glass attenuations and/or consolidations. The pathologic findings of Group I were interstitial or intraalveolar edema, intraalveolar hemorrhage and coagulation necrosis. Diffuse ground glass opacities with interstitial thickening were noted in 20% (n=2/10) of Group I and in 60% (n=9/15) of Group II at the 30 minute CT; however, there was no statistical difference between the two groups (p=0.09). Consolidations with air bronchogram were noted in 22.2% (2/9) of Group I and in 38.5% (5/13) of Group II at the 4 hour CT. The main pathologic findings of consolidations were intraalveolar hemorrhage and coagulation necrosis. There was no statistical difference in the extent of the lesions between Group I and Group II (p=0.20, 0.14, 0.59 and 0.46 at 4, 24, 48 and 72 hours, respectively). The CT findings of Group IIa and Group IIb were not significantly difference. The CT findings of Group III were normal in all 5 rabbits. CONCLUSION: Because there was no significant difference for the extent of lung injury induced by oleic acid between the group treated with high dose methyl prednisolone and non-treated group on CT scans, high dose steroid therapy for acute respiratory distress syndrome and pulmonary fat embolism may not be effective in the acute stage.

Clinical implication of Dendritic Cell Infiltration in Cervical Tuberculous Lymphadenitis / 결핵및호흡기질환

BACKGROUND: Cervical tuberculous lymphadenopathy is a very common disease with a similar incidence to pulmonary tuberculosis. Dendritic cells play a role of initial antigen presentation of this illness. Nevertheless, the precise role of these antigen-presenting cells according to the clinical features in unclear. The aim of this study was to determine the clinical implication of dendritic cell infiltration in the cervical lymph nodes. METHODS: A review of the clinical characteristics was carried out retrospectively based on the clinical records and radiography. Immunohistochemical staining was performed on the available histology specimens of 72 cases using the S-100b polyclonal antibody for dendritic cells. The number of dendritic cells with tuberculous granuloma were determined. A x2 test, unpaired T test and multiple logistic regression analysis were performed. RESULTS: Thirty percent of subjects had previous or concurrent pulmonary TB. Twenty one percent of cases showed a positive reaction on the AFB stain. Within a granuloma, the number of infiltrated dendritic cells was 113.0+/-7.0. The incidence of fever and cough decreased with increasing infiltration of dendritic cells Multivariate regression analysis showed that the infiltration of dendritic cells could significantly contribute to fever. CONCLUSION: Overall, dendritic cells can control a Mycobacterium tuberculosis infection and modulate the immune response, as well as resolve the clinical manifestations of TB lymphadenopathy.

An Aggressive, Rapidly Increasing Angiomyxoma of the Scrotum / 대한비뇨기과학회지

Aggressive Angiomyxoma (AAM) is a recently discovered locally infiltrative tumor that occurs almost exclusively in the pelvic and perineal regions of relatively young females. However, reports of AAM in males are rare. We report here on a rare case of a huge AAM (16x15x11cm, 3,150gm) that developed in the scrotum of a Korean man. Despite the histological benign nature of this tumor, performing wide excision and strict postoperative control are recommended because of the risk of tumor recurrence.

A Case of Nonsecretory Multiple Myeloma with Atypical Imaging Features

Multiple myeloma usually shows homogeneous enhancement on contrast-enhanced Magnetic Resonance imaging (MRI), and is accompanied by a monoclonal gammopathy in serum or urine. We report a case of nonsecretory myeloma, the diagnosis was difficult due to the absence of a monoclonal gammopathy and the presence of atypical imaging features.