Lacrimal gland lesions: Can addition of diffusion-weighted MR imaging improve diagnostic accuracy in characterization?

The aim of the work

To evaluate the diagnostic value of apparent diffusion coefficient (ADC) maps in the characterization of lacrimal gland lesions.

Material and methods

A retrospective study was conducted on 40 patients (26 female and 14 male subjects aged 13–74 years) with lacrimal gland mass. They underwent echo-planar diffusion-weighted magnetic resonance imaging (MRI) of the orbit with a b-factor of 0500 and 1000 s/mm² at 3-Tesla magnetic resonance (MR) unit. ADC maps were reconstructed and the ADC of each mass lesion was calculated. Lesion diagnosis was confirmed by the clinical follow-up or the results of histopathology analysis depending on the specific disease to identify the specificity, sensitivity and accuracy of diffusion-weighted imaging (DWI) in the differentiation between benign and malignant lacrimal lesions.

Results

Forty-two lesions were detected in the examined 40 patients included in this study. Thirty-one were benign and 11 were malignant. The mean ADC value of the malignant lacrimal tumors (0.76 ± 0.14 × 10⁻³ mm²/s) was significantly (P = 0.001) lower than that of the benign lacrimal lesions (1.17 ± 0.22 × 10⁻³ mm²/s). A statistically significant (P = 0.001) difference is identified between the subjects with lacrimal adenitis and those with idiopathic orbital inflammatory syndrome (orbital pseudotumor). Lacrimal lymphoma has the lowest ADCs among a wide range of lacrimal masses. The selection of an ADC value of 0.90 × 10⁻³ mm²/s as a threshold value for differentiating malignant tumors from benign lacrimal lesions has an accuracy of 90%, a sensitivity of 90%, and specificity of 89%.

Conclusion

ADC offers a useful reliable safe non-invasive imaging parameter that can be used for the differentiation of malignant tumors from benign lacrimal lesions with high sensitivity and specificity. The absence of contrast media in DWI reduces the cost of the examination and leads to an increase in the overall accuracy of MRI, hence reducing the number of false positive results and consequently reducing the number of unnecessary biopsies.     

Does combined imaging of the pre- and postsynaptic dopaminergic system increase the diagnostic accuracy in the differential diagnosis of parkinsonism?

Purpose We hypothesized that combining pre- and postsynaptic quantitative information about the dopaminergic system would provide a higher diagnostic accuracy in the differential diagnosis of parkinsonism than specific striatal D₂ receptor binding alone. Therefore, the aim of the study was to introduce new semi-quantitative parameters and evaluate their ability to discriminate between Parkinson’s disease (IPS) and non-idiopathic parkinsonian syndromes (non-IPS). Methods In 100 patients (69 IPS, 31 non-IPS), postsynaptic [¹²³I]IBZM and presynaptic [¹²³I]FP-CIT SPECT scans were evaluated by observer-independent techniques. The diagnostic performances of striatal dopamine transporter (DAT) and D₂ receptor binding, their respective asymmetries, and a combination of pre- and postsynaptic asymmetry were evaluated with ROC analyses. A logistic regression model was generated combining factors to calculate the probability for each patient of belonging to either diagnostic group. Results D₂ receptor binding provided a sensitivity of 87.1% and a specificity of 72.5% with an area under the curve (AUC) of 0.866. The AUCs of other single parameters were lower than that of D₂ binding. A gain of diagnostic power (p = 0.026) was reached with a model combining pre- and postsynaptic asymmetries and D₂ binding (sensitivity 90.3%, specificity 73.9%, AUC 0.893). Conclusion The combination of quantitative parameters of presynaptic DAT and postsynaptic D₂ receptor binding demonstrates superior diagnostic power in the differentiation of patients with IPS and non-IPS than the established approach based on D₂ binding alone. Striatal D₂ receptor binding and the combination of DAT and IBZM binding asymmetries are the factors contributing most in separating these diagnostic groups.     

Liver diffusion-weighted MR imaging: the tower of Babel?

There is a growing amount of literature regarding diffusion-weighted imaging (DWI) of the liver. The apparent diffusion coefficient (ADC) was introduced in 1986 and is used extensively in studies. However, methods for calculating ADC vary considerably and the value of the ADC strongly depends on the b values chosen for its calculation. Indeed, the ADC incorporates the effects of both diffusion and perfusion, which can vary independently. Since signal attenuation as a function of b follows a bi-exponential pattern, other diffusion/perfusion coefficients can be calculated using DWI, and these may provide more meaningful measurements than the ADC. The absence of standardization for both the terminology and the methodology in DWI of the liver makes it difficult for readers to understand the technique used and strongly limits comparisons between studies. Here, we review the main principles of DWI of the liver, the limits of the ADC, and the exciting capabilities of multi-parametric DWI. We also insisted on the need for a common language for DWI of the liver.     

Traumatic injuries of the pelvis and thoracic and lumbar spine: does thin-slice multidetector-row CT increase diagnostic accuracy?

The objective is to evaluate different multidetector-row CT (MDCT) strategies for adequate classification of spinal and pelvic injuries. Seventy intubated patients after multiple trauma underwent conventional radiography (CR) and MDCT. Examinations included the pelvis (P), the lumbar spine (LS) and the thoracic spine (TS). Conventional radiographs, 3-mm (CT5) and 5-mm scans (CT3) and 3-mm and 5-mm scans combined with MPR (CT3R/CT5R) were compared to surgery, autopsy and clinical course. MDCT led to significantly better results than CR (P<0.01). Correlation coefficients were r=1.0 (CT3R), r=0.96 [TS] to r=1.0 [P/LS] (CT5R), r=0.8 [P] to r=1.0 [TS] (CT3), r=0.80 [P] to r=0.86 [TS] (CT5) and r=0.3 [TS] to r=0.69 [P] (CR). Fractures were identified by CT3R in 100% of cases, by CT5R in 95%, by CT3 in 90% [P]–100% [TS], by CT5 in 83.3% [LS]–90% [P] and by CR in 57.1% [TS]–87.2% [P]. Unstable fractures were identified in 100% by CT3R, CT5R and CT3, 85.7% [TS]–100% [P/LS] by CT5 and 57.1% [TS]–80% [P] by CR. Only overlapping thin-slice multiplanar reformation allows for an adequate classification of spinal and pelvic injuries and thus is highly emphasized in patients after severe blunt trauma.     

Contrast-enhanced three-dimensional MR angiography of neck vessels: does dephasing effect alter diagnostic accuracy?

The aim of this study was to evaluate diagnostic accuracy of contrast-enhanced MRA (CEMRA) compared with digital subtraction angiography (DSA) in studying neck vessels of 48 patients. In three groups of patients, we used three MRA protocols differing for voxel size to assess if intravoxel dephasing effects could modify accuracy of CEMRA. Accuracy and correlation with DSA results were calculated in all patients and separately in the three groups. A qualitative analysis of the likeness between morphology of the stenosis in CEMRA and DSA images was also assessed. In all patients accuracy and agreement with DSA were 96% and k=0.85 in subclavian arteries, 96% and k=0.84 in vertebral artery, 97% and k=0.88 in common carotid arteries, and 94% and k=0.86 in internal carotid arteries. In the three groups accuracy and agreement with DSA did not show any significant difference. Qualitative analysis of CEMRA and DSA images revealed a better agreement in depicting the morphology of stenosis using a smaller voxel size. The CEMRA represents a powerful tool for the non-invasive evaluation of neck vessels. Overestimation trend of CEMRA is confirmed and the reduction of voxel size, decreasing the dephasing intravoxel effect, allows to have a better overlapping of stenosis morphology on CEMRA compared with DSA, but it does not yield diagnostic gain in the stenosis grading. Electronic Publication     

Interpretations of diffusion-weighted MR imaging by radiology residents in the emergency department: is diagnostic performance influenced by the level of residency training?

Background

To evaluate the diagnostic performance of radiology residents’ interpretations for diffusion-weighted MR imaging (DWI) in the emergency department at different levels of residency training.

Method and materials

A total of 160 patients who underwent DWI with acute neurologic symptoms were included in this retrospective study with an institutional review board approval. Four radiology residents with different training years and one attending neuroradiologist independently assessed the DWI results. Discordances between the results of residents and attending neuroradiologist were classified as follows: false positive (FP) and false negative (FN). We also evaluated the diagnostic performance of four residents according to the reference standard.

Results

Overall, the concordance rate was 84.8 %, with a 15.2 % overall discordance rate. There were 83 FN results. The most common misses were small vessel disease (n = 55), acute focal infarction (n = 10), diffuse axonal injury (n = 6), solitary mass (n = 5), extraaxial hemorrhages (n = 3), posterior reversible encephalopathy syndrome (n = 2), and postictal change (n = 2). Fourteen FP results were interpreted as hemorrhage and acute infarction. The 4th year resident exhibited the highest diagnostic performance, and the level of training had a significant influence on the rates of concordance (P < 0.05). Interobserver reliability was good between the interpretations of the residents and the final interpretations of the attending neuroradiologists.

Conclusion

The level of resident training had a significant effect on their diagnostic performance, and good interobserver reliability was noted between the results of the residents and attending neuroradiologist.

     

Does renal transplantation increase the risk of breast diseases?

PURPOSE: To evaluate the risk of breast pathology occurrence in a group of kidney transplanted patients. MATERIAL: and methods. In the last five years, 30 kidney-transplanted women underwent systematic breast evaluation in our institution and were included in this retrospective study (exposed-group). To compare with this exposed-group, 90 non transplanted women undergoing breast evaluation in the same period at our institution (non-exposed group), were retrospectively randomized. In both groups, results of breast evaluation were classified in two categories (normal and abnormal) and distribution of benign and malignant breast pathologies were evaluated. The mean exposition-time was determined in months in the exposed-group. Comparative analysis of both groups included a comparison of mean patients age and evaluation of the relative risk (RR) of breast pathology occurrence. RESULTS: Mean exposition time was 72.7+/-66.6 months. The percentages of benign breast pathology were 93.7% in the exposed-group and 83.3% in the non-exposed group. Percentages of cancer were respectively 6.3 and 16.7%. Mean patient age was quite similar in the exposed-group (50.7+/-10 years) and in the non-exposed group (50.6+/-10.5 years). The relative risk of breast pathology occurrence was 1.70 (0.99相似文献   

Does inadequate exercise lower the accuracy of myocardial perfusion scintigraphy?

The predictive accuracy of exercise myocardial perfusion scintigraphy (EMPS) in detecting coronary artery disease (CAD) in patients who fail to achieve an adequate level of exercise is not clear. This investigation was carried out in order to compare the sensitivity, specificity and accuracy of EMPS in adequate exercise patients with those in inadequate exercise patients. We have retrospectively compared the results of EMPS with coronary angiography (CAG). One hundred and forty-eight patients with both tests within 6 weeks were included. Adequate exercise was defined as > or = 85% maximally predicted heart rate for age. The overall sensitivity and specificity of EMPS to detect CAD were 92.5% (74/80) and 75%, (51/68), respectively. The sensitivity and specificity in adequate exercise patients were 94.1% (32/34) and 67.6% (23/34), whereas those in inadequate exercise patients were 91.3% (42/46) and 82.4% (28/34). The accuracy was 80.9% (55/68) and 87.5% (70/80), respectively. Patients with inadequate exercise had lower sensitivity but higher specificity of EMPS for detecting CAD, and achieved a higher accuracy than those with adequate exercise.     

Pancreas: does hyoscyamine butylbromide increase the diagnostic value of helical CT?

Among 50 patients referred for helical computed tomography (CT) of the pancreas, 24 randomly selected patients received 40 mg of hyoscyamine butylbromide to evaluate whether its administration improved image quality and diagnostic findings. Differences between the groups were not statistically significant. It was therefore concluded that hyoscyamine butylbromide does not contribute a diagnostic advantage at helical CT of the pancreas.     

Does PACS improve diagnostic accuracy in chest radiograph interpretations in clinical practice?

Objectives

To assess the impact of a Picture Archiving and Communication System (PACS) on the diagnostic accuracy of the interpretation of chest radiology examinations in a “real life” radiology setting.

Materials and methods

During a period before PACS was introduced to radiologists, when images were still interpreted on film and reported on paper, images and reports were also digitally stored in an image database. The same database was used after the PACS introduction. This provided a unique opportunity to conduct a blinded retrospective study, comparing sensitivity (the main outcome parameter) in the pre and post-PACS periods.We selected 56 digitally stored chest radiograph examinations that were originally read and reported on film, and 66 examinations that were read and reported on screen 2 years after the PACS introduction. Each examination was assigned a random number, and both reports and images were scored independently for pathological findings. The blinded retrospective score for the original reports were then compared with the score for the images (the gold standard).

Results

Sensitivity was improved after the PACS introduction. When both certain and uncertain findings were included, this improvement was statistically significant. There were no other statistically significant changes.

Conclusion

The result is consistent with prospective studies concluding that diagnostic accuracy is at least not reduced after PACS introduction. The sensitivity may even be improved.     

Does muscle inhibition after knee injury increase the risk of osteoarthritis?

Knee pathologies are commonly associated with muscle inhibition, an inability to fully activate the knee extensors during voluntary contractions. This inhibition results in knee extensor weakness, and is thought to limit the functional recovery of the knee joint structures. The possible contribution of persistent knee extensor inhibition to osteoarthritis is discussed.     

Does the application of blood flow restriction during walking exercise influence the accuracy of indirect calorimetry?

ObjectivesIdentify whether the application of blood flow restriction (BFR) during walking influences fraction of expired oxygen (F_eO₂) and carbon dioxide (F_eCO₂) measures, key variables in the calculation of oxygen consumption (V?O₂) via indirect calorimetry.DesignRandomised cross-over.MethodsOn separate visits, sixteen participants completed four experimental sessions (order randomised), each comprising 10 min of treadmill exercise; i.e., with or without BFR (60% arterial occlusion pressure) combined with two different intensity levels (100% or 120% comfortable walking speed). For data analysis, walking speeds within the same condition (with or without BFR) were pooled, and the speed variance was controlled within the statistical model. The F_eO₂, F_eCO₂, V?O₂, volume of carbon dioxide production, minute ventilation (V?E) and respiratory exchange ratio were extracted from the metabolic cart from the fifth min of the exercise period to the 3 min post-exercise. Measures were averaged across 2 min increments during exercise and 1 min increments post-exercise.ResultsCondition × time interactions were observed for F_eO₂ (p < 0.01) and F_eCO₂ (p < 0.01). Post hoc analysis identified within the BFR condition an increase in F_eO₂ (p < 0.01) during the exercise period and for 2 min post-exercise, while F_eCO₂ was decreased (p < 0.01) during the exercise period and 1 min post-exercise. A main effect of BFR and time was observed for V?E (p ≤ 0.044) and V?O₂ (p ≤ 0.01).ConclusionsThe increase of F_eO₂ and decrease of FeCO₂ during BFR walking likely reduces the validity of V?O₂ values calculated via indirect calorimetry.     

Body diffusion-weighted MR imaging of uterine endometrial cancer: Is it helpful in the detection of cancer in nonenhanced MR imaging?

Objective

In this study, the authors discussed the feasibility and value of diffusion-weighted (DW) MR imaging in the detection of uterine endometrial cancer in addition to conventional nonenhanced MR images.

Methods and materials

DW images of endometrial cancer in 23 patients were examined by using a 1.5-T MR scanner. This study investigated whether or not DW images offer additional incremental value to conventional nonenhanced MR imaging in comparison with histopathological results. Moreover, the apparent diffusion coefficient (ADC) values were measured in the regions of interest within the endometrial cancer and compared with those of normal endometrium and myometrium in 31 volunteers, leiomyoma in 14 patients and adenomyosis in 10 patients. The Wilcoxon rank sum test was used, with a p < 0.05 considered statistically significant.

Results

In 19 of 23 patients, endometrial cancers were detected only on T2-weighted images. In the remaining 4 patients, of whom two had coexisting leiomyoma, no cancer was detected on T2-weighted images. This corresponds to an 83% detection sensitivity for the carcinomas. When DW images and fused DW images/T2-weighted images were used in addition to the T2-weighted images, cancers were identified in 3 of the remaining 4 patients in addition to the 19 patients (overall detection sensitivity of 96%). The mean ADC value of endometrial cancer (n = 22) was (0.97 ± 0.19) × 10⁻³ mm²/s, which was significantly lower than those of the normal endometrium, myometrium, leiomyoma and adenomyosis (p < 0.05).

Conclusion

DW imaging can be helpful in the detection of uterine endometrial cancer in nonenhanced MR imaging.     

Does football cause an increase in degenerative disease of the lumbar spine?

Degenerative disease of the lumbar spine is exceedingly common. Whether any specific activity increases the likelihood of developing degenerative disc disease (DDD) or facet degeneration (FD) has enormous implications. Within the field of occupational medicine there are specific activities, occupations, and morphologic characteristics that have been related to low back pain. Several specific risk factors have been conclusively linked to low back pain, and in particular DDD and FD. Within the sport of American football, there has long been the feeling that many athletes have or will develop low back pain, DDD, and FD. Proving that certain risk factors present in football will predictably lead to an increase in LBP, DDD, and FD is more difficult. At this time, it can be said that football players, in general, increase their risk of developing low back pain, DDD, and FD as their years of involvement with their sport increase. Because specific spine injuries like fracture, disc herniation, and spondylolysis are more frequent in football players, the resulting DDD and FD are greater than that of the general population. The weightlifting and violent hyperextension that are part of American football are independent risk factors for degenerative spine disease.     

MR first pass perfusion of benign and malignant cardiac tumours—significant differences and diagnostic accuracy

Objectives  

To determine the diagnostic value of magnetic resonance (MR) first pass perfusion in the differentiation of benign and malignant cardiac tumours.