Spontaneous Transient Lateral Thoracic Lung Herniation Resulting in Systemic Inflammatory Response Syndrome (SIRS) and Subsequent Contralateral Lung Injury.

Lung herniation is a relatively rare clinical entity that is most commonly either congenital or acquired traumatically. We describe a case of spontaneous lung herniation secondary to acute cough in an obese male smoker complicated by contralateral acute lung injury and systemic inflammatory response syndrome (SIRS). Mechanisms of lung herniation, classification, diagnosis, and management will be discussed.

Characterizing and predicting pathologic spine fractures in myeloma patients with FDG PET/CT and MR imaging.

OBJECTIVES: To determine if FDG PET/CT scans can be used to discriminate between old and new pathologic spine fractures in myeloma patients and also to determine if there is any combination of PET/CT and MR imaging findings that may indicate an impending spine fracture. MATERIALS AND METHODS: Retrospective review, after IRB approval, by two musculoskeletal radiologists and one nuclear medicine physician was done. PET/CT database was searched to identify studies performed in myeloma patients, using the search terms myeloma, plasmacytoma, or plasma cell. Records, for this group of 176 patients, were searched for concurrent spine MR imaging and report of fracture. The SUV(max) was recorded for each vertebral level from C2 through L5. All other imaging studies carried out in each patient (spine radiographs, spine CTs, and spine MRIs) and clinical records also were reviewed. Spine fractures were identified using the Genant system. MR imaging findings noted included signal intensity, pattern of involvement, as well as the size and location, within the vertebral body, of individual focal lesions. RESULTS: 31 of the 176 patients had concurrent spine MR imaging and report of fracture. Five of these 31 patients were excluded because they had no documentation of the age of fracture prior to PET/CT imaging. The 26 remaining patients (598 vertebral levels) included 17 men and 9 women. There were a total of 59 PET/CTs, 104 spine X-ray studies, 25 spine CT exams, and 71 spine MRI exams. There were a total of 134 vertebral body fractures: 27 were determined to be acute/subacute and pathologic due to active myeloma, 1 was determined to be new but owing to simple osteoporosis, and 106 were determined to be old. The mean SUV(max) in the acute/subacute pathologic fractures was 2.9 with a range from 1.1 to 4.3 (standard deviation 0.98). The old fractures had a mean SUV(max) of 1.6 with a range from 0.6 to 3.1 (standard deviation 0.55). This was a statistically significant difference with p value <.0001. The 464 vertebral bodies without fracture had a mean SUV(max) of 1.8. SUV(max) ≥2.5 was seen at 49 vertebral levels, including 27 with a fracture and 22 without a fracture. SUV(max) ≥3.5 was found at 9 vertebral levels, including 6 with a fracture and 3 without a fracture. The combination of diffuse or multifocal MR patterns and SUV > 3.5 was seen at 7 levels, all but one with new pathologic fractures. CONCLUSION: PET/CT SUV > 3.2 alone can be used in myeloma patients to discriminate between old and new pathologic fractures, just as it has been reported in other types of cancer patients. The combination of PET/CT SUV > 3.5 and MR findings of diffuse or multifocal vertebral body involvement seems to indicate an impending fracture.

Can diffusion-weighted imaging be used to differentiate benign from pathologic fractures? A meta-analysis.

OBJECTIVE: Conventional MR sequences are sometimes nonspecific in differentiating benign from pathologic fractures. To address this difficulty, diffusion-weighted images were conjectured to aid in this discrimination with variable results. As each of these studies contained somewhat small numbers of patients, we performed a meta-analysis to determine if this sequence may be used for this important diagnostic problem. MATERIALS AND METHODS: We reviewed and statistically analyzed the results of eight studies, performed between 1998 and 2003, comparing diffusion-weighted magnetic resonance signal intensity characteristics of benign and pathologic vertebral body fractures. Diffusion-weighted imaging (DWI) signal characteristics and apparent diffusion coefficient (ADC) values of 104 benign fractures and 161 combined malignant vertebral body lesions and pathologic fractures were statistically evaluated in terms of mean ADC, as well as percentage classified as either hypointense or isointense. The meta-analysis to compare benign fractures with the combined pathologic fractures and metastatic lesions in terms of mean ADC used Hedge's g statistic with a small sample bias adjustment; the comparison of the percentage hypo- or isointense used the Mantel-Haenszel method to calculate a weighted summary odds ratio. All summary effect sizes were computed under a random effects model to account for study heterogeneity. RESULTS: The mean ADC was significantly higher (p < 0.01) among benign fractures, with a standardized mean difference (SMD) of 2.8 and a 95% confidence interval (CI) for the SMD of 2.1 to 3.5. Lesions classified as hypointense were significantly more likely to be benign (p < 0.01), based on a summary odds ratio (OR) of 24.5 and 95% confidence that the OR exceeds 1.7. Lesions classified as isointense were not significantly more likely to be benign or malignant (p > 0.1), based on a summary OR of 3.6 and a 95% CI for the OR of 0.35 to 36.6. CONCLUSION: Even though the literature has been inconsistent, ADC maps appear to be a reliable method to differentiate benign from malignant fractures.

Reactive endplate marrow changes: a systematic morphologic and epidemiologic evaluation.

PURPOSE: To evaluate the morphology and location of vertebral endplate changes, and to analyze their association with age, gender, and body mass index (BMI). DESIGN AND PATIENTS: At 1.5 T (T1-weighted, T2-weighted/STIR) 100 lumbar spines were evaluated separately by three observers. The readers classified the endplate bone marrow abnormalities on sagittal MR images according to the definitions of Modic et al. Findings were localized by disc segment; whether in the upper and/or lower endplate; and within each endplate divided into 15 segments. Disc space narrowing, as well as disc desiccation, was also noted at each vertebral level. In addition, endplate changes were correlated with age, gender, and BMI (weight(kg)/height(m)2). RESULTS: A total of 15,000 data points were studied and 422 total changes recorded. A total of 99 vertebral levels were affected in 58 patients. Of these, 171 were of type I, 242 were of type II, and 9 were of type III. L4-L5 and L5-S1 vertebral levels were most commonly involved, having (142, 4.73%) and (116, 3.87%) changes respectively (P<0.0001). The upper and lower aspects of the endplate were affected similarly. Changes most frequently occurred at the anterior aspect of the endplate (P<0.0001). Endplate marrow changes were associated with increasing age (P<0.0001) and, surprisingly, male gender (P<0.0001). Endplate changes were not associated with BMI. CONCLUSION: The fatty pattern was most common, with the sclerotic pattern being rare. Endplate marrow changes most often occurred at the anterior aspect of the endplate, particularly at L4--L5 and L5--S1 levels. Modic changes occur more frequently with aging, evidence of their degenerative etiology. They were, however, not related to body habitus, but to weight and male gender.

Accuracy of plain films, and the effect of experience, in the assessment of ankle effusions.

OBJECTIVE: To investigate the accuracy of plain radiographs, and the effect of observer experience, in the assessment of ankle effusions compared with an MRI gold standard. DESIGN AND PATIENTS: Anteroposterior (AP) and lateral radiographs of the ankle of 39 patients were evaluated by four observers, ranging from first-year radiology resident to an attending musculoskeletal radiologist. Observers independently graded the lateral films from 0 to 5 at one sitting, and the AP films at a second sitting. All patients had an MRI scan performed within 48 h of the ankle radiographs, on which distention of the anterior recess was used as the gold standard for an effusion. RESULTS: Lateral radiographs had variable sensitivity (range 17-63%), but specificity (81-94%) was usually high. AP radiographs similarly had variable sensitivity (15-55%), but their specificity (63-75%) was surprisingly good. Overall, sensitivity and specificity were inversely proportional and more related to individual variability than experience (observer 1, 53% and 81%; observer 2, 17% and 94%; observer 3, 63% and 88%; observer 4, 21% and 94%); however, individual sensitivity and specificity were consistent between AP and lateral radiographs (observer 1, 53% and 81%, 50% and 65%; observer 2, 17% and 94%, 15% and 75%), observer 3, 63% and 88%, 55% and 63%; observer 4, 21% and 94%, 25% and 70%). Positive predictive value was reasonably good for lateral radiographs (range 75-86%); however, it was fairly low for AP radiographs (38-61%). Negative predictive value was low for both lateral (50-67%) and AP (47-58%) radiographs. Accuracy was low for both AP (45-59%) and lateral (53-74%) radiographs. As expected, individual accuracy was consistently higher for lateral radiographs than for AP radiographs (observer 1, 65% and 58%; observer 2, 53% and 45%; observer 3, 74% and 59%; observer 4, 54% and 48%). CONCLUSIONS: For the diagnosis of ankle effusions the overall accuracy of radiographs was surprisingly low. Quite surprisingly, the diagnosis of effusions on AP radiographs was not much poorer than on lateral films. Results, however, varied little with experience and training.

MRI findings of septic arthritis and associated osteomyelitis in adults.

OBJECTIVE: The purpose of this study was to describe the soft-tissue, synovial, and osseous MRI findings of septic arthritis. MATERIALS AND METHODS: At 1.5 T (T1-weighted, T2-weighted or STIR, and contrast-enhanced images), 50 consecutive cases of septic arthritis were evaluated by two observers for synovial enhancement, perisynovial edema, joint effusion, fluid outpouching, fluid enhancement, and synovial thickening. The marrow was assessed for abnormal signal on T1- and T2-weighted images or after contrast enhancement. We noted whether the marrow signal was diffuse or abnormal in bare areas. MRI findings were compared with microbiologic, clinical, and surgical data and diagnoses. RESULTS: The frequency of MRI findings in septic joints was as follows: synovial enhancement (98%), perisynovial edema (84%), joint effusions (70%), fluid outpouching (53%), fluid enhancement (30%), and synovial thickening (22%). The marrow showed bare area changes (86%), abnormal T2 signal (84%), abnormal gadolinium enhancement (81%), and abnormal T1 signal (66%). Associated osteomyelitis more often showed T1 signal abnormalities and was diffuse. CONCLUSION: Synovial enhancement, perisynovial edema, and joint effusion had the highest correlation with the clinical diagnosis of a septic joint. However, almost a third of patients with septic arthritis lacked an effusion. Abnormal marrow signal-particularly if it was diffuse and seen on T1-weighted images-had the highest association with concomitant osteomyelitis.