The application of MR imaging in the detection of hip involvement in patients with ankylosing spondylitis

Objective

To investigate the changes in hip MR imaging, evaluate the frequency of hip involvement and compare the value of clinical symptoms, radiographs, and MR imaging in the detection of hip involvement in patients with ankylosing spondylitis (AS).

Methods

Anteroposterior radiographs of the pelvis, MR imaging of the hip and clinical evaluation were undertaken in 58 patients with definite AS. All patients were followed up 3 years. Annual radiographs and clinical evaluation were carried out. The imaging data were independently assessed by two experienced radiologists who were blinded to patient identity and clinical characteristics. Based on the Bath Ankylosing Spondylitis Radiology Hip Index (BASRI-hip) scoring system, BASRI-hip scores ≥2 were defined as radiological hip involvement. On MR imaging, both acute and chronic inflammatory changes were considered positive signs for hip involvement. Symptomatic hip involvement was defined as current or past pain or limitation of the hip movement. The statistical analysis was performed using the χ² test for comparison of sensitivity among clinical symptoms, radiographs, and MR imaging in the detection of hip involvement and the Student's t-test for comparison of disease duration between with and without hip involvement. A P value <0.05 was considered to be statistically significant. For interpreting MRI and radiographs, the percentage of agreement between the two assessors and the kappa coefficients were calculated.

Results

On MR imaging, positive changes were detected in 86 (74.1%) hips among 116 hips in all 58 patients. Joint effusion was observed in 73 (62.9%) hips; 23 out of 27 patients who underwent fat-saturated contrast-enhanced T₁-weighted sequences had abnormal synovial enhancement in bilateral hips. The other abnormal MR findings included subchondral bone marrow edema in 35 (30.2%) hips, enthesitis in 22 (19.0%) hips, fatty accumulation of the bone marrow in 28 (24.1%) hips, bone erosive destruction in 32 (27.6%) hips, and joint-space narrowing in 4 (3.4%) hips. Based on the BASRI-hip scoring system, 68, 24, 18, 6 and 0 hips had no, suspicious, mild, moderate or severe damage on conventional radiographs of the pelvis, respectively. Thirty-five hips in 20 patients had current or past pain or limitation. The proportion of hip involvement according to MR imaging, radiographs, and clinical symptoms was 74.1% (86/116), 20.7% (24/116), and 30.2% (35/116), respectively. MR imaging yielded higher values than radiographs and clinical symptoms in the detection of hip involvement in patients with AS (χ² = 66.45 and 44.93, P <0.05). Interreader reliability for interpretation of findings was acceptable for both MRI and radiographs. During follow-up, radiological hip involvement were found in 10 hips with BASRI-hip scores ≤1 at baseline and clinical symptoms appeared in 15 sides of the original asymptomatic hip. On baseline MR imaging, inflammatory changes were seen in all hips which appeared symptoms and/or radiological involvement both at baseline and during follow-up.

Conclusion

The proportion of hip involvement is much higher than that suggested by radiographic changes and clinical symptoms. MR imaging is superior to conventional radiographs and clinical symptoms in the detection of hip involvement. Joint effusion and synovial enhancement caused by synovitis are the commonest hip findings on MR imaging in patients with AS.     

The iliac wing sign: an indicator of the presence of bone and/or soft-tissue injury of the pelvis and hips

Purpose

To prospectively evaluate the feasibility of using the “iliac wing sign (IWS)” as an indicator of bone and/or soft-tissue injury of the pelvis and hips on magnetic resonance (MR) imaging. IWS means edema of the iliacus muscle attachment entering the iliac wing that is visualized as a linear high signal intensity on fat-suppressed T2-weighted MR images.

Methods

Consecutive 106 patients who complained of hip pain were enrolled in this study. We evaluated the correlation between IWS and bone and/or soft-tissue injury of the pelvis and hips using Fisher's exact test. Further, performance parameters of sensitivity, specificity, accuracy, the positive predictive value (PPV), and negative predictive value (NPV) of IWS were calculated.

Results

Thirty-eight of the 106 (36%) patients had bone and/or soft-tissue injury. Twenty-seven of these 38 (71%) patients with injury showed a positive IWS, while only 11 of 68 (16%) patients without injury showed a positive IWS (p < .0001). IWS, thus, yielded a sensitivity of 71%, specificity of 84%, accuracy of 79%, positive predictive value (PPV) of 71%, and negative predictive value (NPV) of 84%.

Conclusion

In cases with a positive IWS, the careful interpretation of MR images is needed because injury presence is highly likely, as suggested by the relatively high sensitivity and PPV. IWS absence may mean a low probability of injury because of the high specificity and NPV.     

Usefulness of perfusion weighted magnetic resonance imaging with signal-intensity curves analysis in the differential diagnosis of sellar and parasellar tumors: Preliminary report

Purpose

The most common pituitary tumors are adenomas, which however may be mimicked by other tumors that can show a very similar appearance in plain MRI. The aim of our study was to evaluate the usefulness of perfusion weighted MR imaging (PWI), including signal-intensity curves analysis in the differential diagnosis of sellar/parasellar tumors.

Methods

Forty-one patients with sellar/parasellar tumors (23 macroadenomas, 10 meningiomas, 5 craniopharyngiomas, 1 intrasellar hemangioblastoma, 1 intrasellar prostate cancer metastasis, 1 suprasellar glioma), underwent plain MRI followed by PWI using a 1.5T unit. In each tumor, the mean and maximum values of relative cerebral blood volume (rCBV), as well as the relative peak height (rPH) and the relative percentage of signal intensity recovery (rPSR) were calculated.

Results

The high perfusion tumors were: macroadenomas, meningiomas, squamous-papillary type of craniopharyngiomas, hemangioblastoma, glioma and metastasis. The low perfusion neoplasms included adamantinomatous type of craniopharyngiomas. By comparing adenomas and meningiomas, we found statistically significant differences in the mean and maximum rCBV values (p = 0.026 and p = 0.019, respectively), but not in rPH and rPSR. The maximum rCBV values >7.14 and the mean rCBV values >5.74 with the typical perfusion curve were very suggestive of the diagnosis of meningioma. There were differences between adenomas and other high perfusion tumors in rPH and rPSR values.

Conclusions

PWI can provide additional information helpful in differential diagnosis of sellar/parasellar tumors. In our opinion PWI, as an easy to perform and fast technique should be incorporated into the MR protocol of all intracranial neoplasms including sellar/parasellar tumors.     

Quantitative chemical-shift MR imaging cutoff value: Benign versus malignant vertebral compression – Initial experience

Purpose

To evaluate the diagnostic accuracy of in-phase/opposed-phase quantitative chemical shift magnetic resonance (MR) imaging of the spine and to determine the cutoff value that enables differentiation of malignant from benign compression fractures, in patients with known primary malignancy.

Patients and methods

Prospective assessment of thirty-two patients with known primary malignancy who presented with vertebral compression fractures, MR imaging of the spine at 1.5 Tesla with standard conventional MR sequences and additional chemical shift (in-phase/opposed-phase) imaging was done. Quantitative image analysis by drawing regions of interest (ROI) on the abnormal marrow of compressed (study group) and adjacent normal vertebra (control group) was also performed in each patient. The signal intensity ratio (SIR) of the marrow was determined by dividing the mean signal intensity on the opposed-phase to the mean signal intensity on the in-phase images and statistical analysis was performed.

Results

Mean SIR of benign vertebral compression [0.73 ± 0.07 (range 0.12–1.2)] was significantly lower than malignant SIR values [1.72 ± 0.14 (range 0.8–2.96)] (p < 0.0001; area under the ROC curve, 0.97). The optimal SIR cutoff value for separating benign and malignant vertebral compression was found to be 0.91 with a calculated sensitivity of 93%, specificity of 82% and accuracy of 88%.

Conclusion

Quantitative chemical shift MR imaging could be a valuable addition to standard MR imaging techniques and represent a rapid problem solving tool in differentiating benign from malignant vertebral compression, especially in patients with known primary malignancies.     

Can symptomatic acromioclavicular joints be differentiated from asymptomatic acromioclavicular joints on 3-T MR imaging?

Objective

To evaluate retrospectively whether symptomatic acromioclavicular joints can be differentiated from asymptomatic acromioclavicular joints on 3-T MR imaging.

Methods

This study included 146 patients who underwent physical examination of acromioclavicular joints and 3-T MR imaging of the shoulder. Among them, 67 patients showing positive results on physical examination were assigned to the symptomatic group, whereas 79 showing negative results were assigned to the asymptomatic group. The following MR findings were compared between the symptomatic and asymptomatic groups: presence of osteophytes, articular surface irregularity, subchondral cysts, acromioclavicular joint fluid, subacromial fluid, subacromial bony spurs, joint capsular distension, bone edema, intraarticular enhancement, periarticular enhancement, superior and inferior joint capsular distension degree, and joint capsular thickness. The patients were subsequently divided into groups based on age (younger, older) and the method of MR arthrography (direct MR arthrography, indirect MR arthrography), and all the MR findings in each subgroup were reanalyzed. The meaningful cutoff value of each significant continuous variable was calculated using receiver operating characteristic analysis.

Results

The degree of superior capsular distension was the only significant MR finding of symptomatic acromioclavicular joints and its meaningful cutoff value was 2.1 mm. After subgroup analyses, this variable was significant in the older age group and indirect MR arthrography group.

Conclusion

On 3-T MR imaging, the degree of superior joint capsular distension might be a predictable MR finding in the diagnosis of symptomatic acromioclavicular joints.     

Association of degree and type of edema in posterior reversible encephalopathy syndrome with serum lactate dehydrogenase level: initial experience

Purpose

Posterior reversible encephalopathy syndrome (PRES) is a clinicoradiologic entity characterized by headache, blurred vision and seizures with typical parieto-occipital predominantly vasogenic edema, occasionally with cytotoxic edema. The association between the degree and type of edema in PRES with biochemical parameter, especially serum lactate dehydrogenase, has not been determined.

Material and methods

Thirty-five patients with typical clinical symptoms and characteristic MR imaging findings of PRES were included in this study. The extent of brain edema was graded on the anatomical distribution by 2 observers blinded to patients’ clinical record, as well as the type of brain edema determined on DWI and ADC map. The levels of biochemical parameters were correlated with the degree of edema and compared between different types of edema.

Results

Serum LDH concentrations between patients with cytotoxic edema and with vasogenic components were not statistically different (NWU test, U = 93.0, Z = 1.818, P = 0.069). Only serum lactate dehydrogenase (LDH) concentration was significantly correlated with the score of brain edema distribution (Spearman's rho correlation, r = 0.721, P = 0.00). No relationship was found between other biochemical parameters and the degree and type of brain edema.

Conclusion

Increased serum LDH level, which plays an essential role in endothelial injury, may be a potential risk factor for the development of edema in PRES.     

Validation of Fourier decomposition MRI with dynamic contrast-enhanced MRI using visual and automated scoring of pulmonary perfusion in young cystic fibrosis patients

Purpose

To validate Fourier decomposition (FD) magnetic resonance (MR) imaging in cystic fibrosis (CF) patients with dynamic contrast-enhanced (DCE) MR imaging.

Materials and methods

Thirty-four CF patients (median age 4.08 years; range 0.16–30) were examined on a 1.5-T MR imager. For FD MR imaging, sets of lung images were acquired using an untriggered two-dimensional balanced steady-state free precession sequence. Perfusion-weighted images were obtained after correction of the breathing displacement and Fourier analysis of the cardiac frequency from the time-resolved data sets. DCE data sets were acquired with a three-dimensional gradient echo sequence. The FD and DCE images were visually assessed for perfusion defects by two readers independently (R1, R2) using a field based scoring system (0–12). Software was used for perfusion impairment evaluation (R3) of segmented lung images using an automated threshold. Both imaging and evaluation methods were compared for agreement and tested for concordance between FD and DCE imaging.

Results

Good or acceptable intra-reader agreement was found between FD and DCE for visual and automated scoring: R1 upper and lower limits of agreement (ULA, LLA): 2.72, −2.5; R2: ULA, LLA: ±2.5; R3: ULA: 1.5, LLA: −2. A high concordance was found between visual and automated scoring (FD: 70–80%, DCE: 73–84%).

Conclusions

FD MR imaging provides equivalent diagnostic information to DCE MR imaging in CF patients. Automated assessment of regional perfusion defects using FD and DCE MR imaging is comparable to visual scoring but allows for percentage-based analysis.     

CT and MR imaging findings of sinonasal angiomatous polyps

Objective

To characterize the CT and MR imaging findings of patients with sinonasal angiomatous polyps (SAPs) and evaluate their respective clinical value in the diagnosis of SAP.

Methods

CT and MR imaging findings of 15 patients with pathologically proven SAP were examined. Assessed image features included location, size, margin, attenuation, and change of the bony walls of the sinonasal cavity on CT, and signal intensity and enhancement pattern on MR.

Results

On CT, the SAP was mostly isoattenuated with patches of slight hyperattenuation. Most lesions caused changes in the adjacent bone, including expansile remodeling (n = 8), defect or destruction (n = 7), and hyperostosis (n = 6). All lesions examined by MR showed heterogeneous isointense signal intensity on T1-weighted images and mixed obvious hyperintense and hypointense signal intensity with linear hypointense septum internally (n = 10), and hypointense peripheral rim on T2-weighted images (n = 10). Postcontrast MR images demonstrated areas of heterogeneous and marked enhancement with an unenhanced hypointense rim and septa (n = 7).

Conclusions

CT and MR imaging have respective advantages in the diagnosis of SAP. Combined application of CT and MR examinations is necessary for patients with suspected SAP.     

Diagnostic value of apparent diffusion coefficient to differentiate benign from malignant vertebral bone marrow lesions

Background

Vertebral collapse is a common problem due to benign bone marrow lesions, trauma or malignant process. The diagnosis is often correctly predicted from characteristic imaging appearance. Some vertebral collapses have atypical imaging appearance that may cause diagnostic confusion.

Aim

To evaluate the value of the ADC obtained in DW-MR sequences for the differentiation between benign and malignant bone marrow lesions.

Patients

Sixty patients were included in this study, referred from Neurosurgery and Radiotherapy Departments and proved to have vertebral compression based on conventional MR imaging.

Results

The ADC value resulted in statistically significant characterization between (osteoporotic and post-traumatic collapse) and (malignant vertebral collapse) (P < 0.0001) while there was no statistically significant findings between infective spondylodiscitis and malignant vertebral collapse (P > 0.05). The sensitivity, specificity, PPV, NPD of DWI and ADC values in differentiating benign from malignant vertebral collapse were 100%, 83.3%, 60% and 100% respectively.

Conclusions

ADC values are a useful complementary MRI tool to characterize bone marrow lesions, in order to distinguish acute benign fractures from malignant or infectious bone marrow lesions. However, ADC values are not valuable in order to differentiate malignancy from infection with diagnostic overlap in the subacute traumatic vertebral collapse.     

MRI of the cuboid bone: analysis of changes in diabetic versus non-diabetic patients and their clinical significance

Objectives

(1) To investigate the association between diabetes and marrow changes in the cuboid; and (2) to evaluate the influence of age, gender, body mass index (BMI) and use of insulin in the occurrence of marrow changes in the cuboid.

Research design and methods

MR and X-ray foot examinations of 237 patients [94 males, 143 females; mean age, 47.1 years (range 16–93 years)], five of whom underwent bilateral examinations, were reviewed. MR and radiographic studies were analyzed for the presence of marrow edema and fractures in the cuboid. Findings were correlated with demographic data (age, gender) and clinical information (BMI and use of insulin).

Results

Two hundred and forty two feet – 69 diabetic and 173 non-diabetic – were retrospectively evaluated. There was a higher prevalence of marrow edema and fractures in the diabetic cuboid (n = 31, 45%) compared to non-diabetic cuboid (n = 25, 14%, p = 0.02). A fracture line was seen in fourteen (20%) diabetic cuboid bones compared to 4 (2%) in non-diabetic cuboid bones (p < 0.0001). Eleven (79%) cases of cuboid fractures in the diabetic population were radiographically occult. Multivariate data analysis revealed an adjusted odds ratio of 4.416 (95% CI; 2.307, 8.454) for the relationship between marrow changes (edema and fractures) in the cuboid and diabetes. For each year of age, the odds of changes in the cuboid increased by 2.2% (95% CI; 1.001, 1.044).

Conclusion

Despite not bearing weight, the cuboid bone is more vulnerable to marrow edema and fractures in diabetic patients compared to non-diabetic patients. Age seems to be an influential factor.     

Enchondroma vs. chondrosarcoma: A simple,easy-to-use,new magnetic resonance sign

Introduction

There is no clear radiologic or pathologic agreement on the differences between enchondroma and conventional chondrosarcoma, which has huge therapeutic consequences. Microscopically, an enchondroma is composed of “islands of intramedullary hyaline cartilage surrounded by marrow fat”, and a chondrosarcoma a “diffuse cartilaginous replacement (invasion) of the marrow which leads to complete ‘trapping’ of host lamellar bone trabeculae.” The marrow around islands of cartilage should be detectable on magnetic resonance imaging (MR). Enchondroma may be the precursor of chondrosarcoma; benign cartilaginous islands are often seen microscopically at the periphery of chondrosarcoma. We attempted to detect these islands at the periphery of chondrosarcomas on MR and correlate them microscopically.

Materials and methods

We examined our database for all patients with a chondrosarcoma of the long and flat bones between 1990 and 2007. Only those with a preoperative MR who underwent an en bloc resection were included, yielding 32 patients. We looked for low-signal islands surrounded by high (fat) signal on T1-weighted images, and high-signal islands surrounded by low signal on T2-weighted fat saturated images at the periphery of the main tumour mass. Microscopic correlation was performed in all cases.

Results

On microscopy, there were 23 conventional chondrosarcomas, nine dedifferentiated. Peripheral islands surrounded by fat were detected on MR in 19 cases, corresponding to benign cartilage in 18 cases and to the benign scar of a needle biopsy tract in one. There were no peripheral islands detected radiographically or microscopically in 13 cases.

Conclusion

Cartilaginous islands microscopically detected at the periphery of some chondrosarcomas are easily and reliably diagnosed on MR.     

Evaluation of spinal trauma by multi detector computed tomography and magnetic resonance imaging

Aim of work

The aim of this work is to assess the role of multi-detector computed tomography (MDCT) and magnetic resonance imaging (MRI) in evaluation of spinal trauma.

Patients and methods

Between January 2013 and April 2014, 98 patients (78 males and 20 females) with spinal injuries were investigated by MDCT and MRI. Assessment of the radiological findings of spinal injury was performed and the following were investigated: vertebral compression fractures, bursts and dislocations, posterior element fractures, C1 and C2 lesions, vertebral listhesis, bone marrow edema, spinal canal compression, disk herniation, extradural hematoma, spinal cord contusions, spinal cord swelling and posterior ligamentous complex injuries.

Result

A total of 271 lesions were diagnosed as follows: 217 lesions were diagnosed using MRI alone, 1 54 lesions were diagnosed using MDCT alone and 100 lesions were diagnosed using MRI and MDCT conjointly. By using MRI 117 more lesions were detected than using MDCT. MRI was significantly superior to MDCT in the diagnosis of bone marrow edema, posterior ligamentous complex injuries, disk herniations, spinal canal compressions, and spinal cord contusions and edema. In cervical spine injuries, MRI was useful for the evaluation of the supporting ligaments and the spinal cord after the patient has been stabilized. The average times required to perform CT and MRI were 1.38 ± 19.83 and 2.00 ± 19.58 days, respectively; this difference was significant (p?0.05) according to the Mann–Whitney test.

Conclusion

MRI was significantly superior to MDCT in the diagnosis of bone marrow edema, posterior ligamentous complex injuries, disk herniations, spinal canal compressions, and spinal cord contusions and edema. In cervical spine injuries, MRI was useful for the evaluation of the supporting ligaments and the spinal cord after the patient has been stabilized.MDCT and MRI are complementary to each other in evaluation of spine injuries.     

Musculoskeletal manifestations of sickle cell disease,diagnosis with whole body MRI

Purpose

The aim of work is to define the musculoskeletal abnormalities in patients with sickle-cell disease using whole body MRI.

Patients and methods

Twenty-seven patients with known sickle cell disease were included in this study complaining of acute painful vaso-occlusive crisis. All the patients complaining of bony pain in different body regions. Some patients complaining of bony swellings and joint pain. Whole body (W.B) MRI studies were performed for all the patients .Three coronal (T1, T2, and STIR) sequences were performed for whole-body MR imaging. In selected cases, dedicated examination of certain body parts was performed.

Results

Persistent red marrow, intramedullary bone hyperplasia and bone infarcts were seen in all patients. Vertebral bone infarcts were found in 23 patients. Bilateral proximal femoral head epiphysis avascular necrosis were found in 9 patients. Osteomylitis was diagnosed in 6 patients and septic arthritis in 2 patients.

Conclusion

Whole body MRI can help identifying muscloskeletal abnormalities in sickle cell disease in a single session. MRI is a useful imaging tool in distinguishing acute osteomylitis and bone infarct. Knowledge of the range of imaging findings is crucial in order to accurately depict the complication and initiate appropriate therapy.     

MR imaging of hepatic metastasis in patients with malignant melanoma: evaluation of suspected lesions screened at contrast-enhanced CT

Purpose

To evaluate the magnetic resonance (MR) imaging feature of suspected hepatic metastasis in patients with malignant melanoma which showed intermediate findings on screened contrast-enhanced computed tomography (CECT).

Materials and methods

MR imaging was performed in 38 patients (22 men, 16 women; mean age, 58 years) whose CECT findings were intermediate. Hepatic metastases had been diagnosed on MR imaging in 23 of the 38 patients. Verification of hepatic metastasis was made by histological examination: ultrasonographic-guided needle biopsy (n = 3), autopsy (n = 3), and surgical resection (n = 1), or by an obvious progression in number and/or size of the lesions on follow-up MR imaging (n = 24). Two diagnostic radiologists reviewed MR images by consensus. The median follow-up duration was 14.2 months.

Results

Abnormal findings were detected in 31 patients on MR images, and undetected in the remaining seven patients resulting in false-positive on CECT. The mean size of the lesion was 11.0 mm. False-positive results were obtained in two lesions which disappeared on follow-up MR imaging. In six patients, lesions were considered as hepatic cysts on MR images. As a result, a total of 35 hepatic metastases were detected on MR images. Of these, 18 patients demonstrated typical melanotic appearance on MR images which showed shortened T1 and T2 relaxation times, and five patients demonstrated atypical melanotic appearance. In 16 patients, extra-hepatic metastases were also developed.

Conclusion

MR imaging could rule out hepatic metastasis in patients with malignant melanoma which showed intermediate findings on screened CECT, and could detect additional extra-hepatic metastases.     

T2-weighted MR imaging of the liver: Qualitative and quantitative comparison of SPACE MR imaging with turbo spin-echo MR imaging

Objective

To qualitatively and quantitatively compare T2-weighted MR imaging of the liver using volumetric spin-echo with sampling perfection with application-optimized contrast using different flip angle evolutions (SPACE) with conventional turbo spin-echo (TSE) sequence for fat-suppressed T2-weighted MR imaging of the liver.

Materials and methods

Thirty-three patients with suspected focal liver lesions had SPACE MR imaging and conventional fat-suppressed TSE MR imaging. Images were analyzed quantitatively by measuring the lesion-to-liver contrast-to-noise ratio (CNR), and the signal-to-noise ratio (SNR) of main focal hepatic lesions, hepatic and splenic parenchyma and qualitatively by evaluating the presence of vascular, respiratory motion and cardiac artifacts. Wilcoxon signed rank test was used to search for differences between the two sequences.

Results

SPACE MR imaging showed significantly greater CNR for focal liver lesions (median = 22.82) than TSE MR imaging (median = 14.15) (P < .001). No differences were found for SNR of hepatic parenchyma (P = .097), main focal hepatic lesions (P = .35), and splenic parenchyma (P = .25). SPACE sequence showed less artifacts than TSE sequence (vascular, P < .001; respiratory motion, P < .001; cardiac, P < .001) but needed a longer acquisition time (228.4 vs. 162.1 s; P < .001).

Conclusion

SPACE MR imaging provides a significantly increased CNR for focal liver lesions and less artifacts by comparison with the conventional TSE sequence. These results should stimulate further clinical studies with a surgical standard of reference to compare the two techniques in terms of sensitivity for malignant lesions.     

Imaging study of ossifying fibroma with associated aneurysmal bone cyst in the paranasal sinus

Objective

To determine the CT and MR imaging features of ossifying fibroma with aneurysmal bone cyst of the paranasal sinus.

Materials and methods

We retrospectively reviewed 15 patients with histopathology-proven ossifying fibromas with aneurysmal bone cysts in the paranasal sinus. All 15 patients underwent CT and MR imaging. The following imaging features were reviewed: location, shape, margin, CT findings, and MR imaging appearances and time-intensity curve of dynamic contrast-enhanced MR imaging.

Results

Ossifying fibromas occurred in the maxillary sinus in one patient, sphenoid sinus in 2, frontal sinus in 3, frontoethmoid sinuses in 3, and ethmoid sinus in 6 patients. Ossifying fibromas showed an elliptic-shape and aneurysmal bone cysts revealed a multicystic appearance, with well-demarcated margins. On unenhanced CT, ossifying fibromas appeared isodense to gray matter with scattered calcifications in nine, ground-glass appearance in 6 patients and aneurysmal bone cysts showed mixed density. Ossifying fibromas appeared isointense to gray matter in 12 and slightly hypointense in three patients on T1-weighted images, and isointense in 4 and hypointense in eleven patients on T2-weighted images, with moderate or marked enhancement after administration of contrast material. The time-intensity curves of eight ossifying fibromas exhibited a rapidly enhancing and rapid washout pattern. The intracystic components of aneurysmal bone cysts showed heterogeneous signal intensity on MR images, with fluid–fluid levels identified clearly by T2-weighted images, without enhancement. The periphery and septa of aneurysmal bone cysts appeared isointense on MR images, with marked enhancement.

Conclusions

Fluid–fluid levels within an elliptic-shape mass with scattered calcifications or ground-glass appearance is highly suggestive of this complicated entity in the paranasal sinus.     

Utility of combined high-resolution bone SPECT and MRI for the identification of rheumatoid arthritis patients with high-risk for erosive progression

Objectives

To evaluate the utility of sequentially acquired, post hoc fused, magnetic resonance imaging (MRI) and multi-pinhole single photon emission computed tomography (MPH-SPECT) with technetium-99m-labeled disphosphonates (Tc99m-DPD) for the identification of finger joints with later erosive progression in early rheumatoid arthritis (ERA) patients.

Methods

Ten consecutive ERA patients prospectively underwent MPH-SPECT and MRI of metacarpophalangeal (MCP) joints prior to and after 6 months methotrexate therapy. Tc99m-DPD uptake was measured at proximal and distal MCP sites using regional analysis. The course of joint pathologies was scored according to the Rheumatoid Arthritis MRI Score (RAMRIS) criteria.

Results

The frequency of increased Tc99m-DPD uptake, synovitis and bone marrow edemadecreased under MTX therapy; but the number of bone erosions increased. Joints with progressive and new erosions on follow-up had a higher baseline Tc99m-DPD uptake (2.64 ± 1.23 vs. 1.43 ± 0.91) (p = 0.02).

Conclusions

Joints with erosive progression are characterized by an early increased Tc99m-DPD uptake, even in absence of MRI bone pathologies. Tc99m-DPD MPH-SPECT might thus be of additional value to morphological MRI for the identification of RA patients with a high risk for erosive progression.     

Magnetic resonance spectroscopy and perfusion weighted imaging as predictors for tumor response to gamma knife radiosurgery: A single center experience

Objective

To test the hypothesis that hemodynamic and metabolic characteristics of intracranial neoplasms detected with magnetic resonance spectroscopy and perfusion weighted imaging are efficient predictors of tumor response to radiosurgery.

Methods

Fifty-four patients with 59 intracranial neoplasms, who underwent evaluation with echoplanar PW and MRS imaging prior to gamma knife radiosurgery were selected for this retrospective analysis. The mean irradiation dose was 13.76 Gy. The mean follow up after GNR constituted 24 months. Predictive diagnostic accuracy was calculated with standard formulas. The association of tumor response to radiosurgery with pretherapeutic MRI parameters was estimated using the Mann–Whitney U test.

Results

Significant association was found between the perfusion and hemodynamic parameters of intracranial neoplasms and the outcome of GKR. Diagnostic accuracy of multimodel MRI was 89% among low grade and 65% among high grade neoplasms. The overall accuracy was 81%. Normalized rCBV, choline, NAA and lipid contents and Chol/cr and NAA/cr were statistically different between low and high grade neoplasms (p < 0.001).

Conclusion

MR perfusion and spectroscopic results provided information that were predictive of the outcome of radiosurgery in this patient pool, increased the diagnostic accuracy of conventional MRI in defining tumor type and grade and may play an important role in pre-therapeutic planning for radiosurgery.     

Role of perfusion-weighted imaging at 3T in the histopathological differentiation between astrocytic and oligodendroglial tumors

Objective

The differentiation of oligodendroglial tumors from astrocytic tumors is important clinically, because oligodendroglial tumors are more chemosensitive than astrocytic tumors. This study was designed to clarify the usefulness of 3 T MR perfusion imaging (PWI) in the histopathological differentiation between astrocytic and oligodendroglial tumors. This is because there is a growing interest in the diagnostic performance of 3 T MR imaging, which has the advantages of a higher signal-to-noise ratio (SNR) and greater spatial and temporal resolution.

Materials and methods

This study retrospectively included 24 consecutive patients with supratentorial, WHO grade II and III astrocytic and oligodendroglial tumors (7 astrocytic, 10 oligoastrocytic, and 7 oligodendroglial tumors) that were newly diagnosed and resected between November 2006 and December 2009 at Hiroshima University Hospital. These patients underwent dynamic susceptibility contrast-enhanced (DSC) PWI relative cerebral blood volume (rCBV) measurements before treatment. Astrocytic tumors were designated as the astrocytic group, and oligoastrocytic and oligodendroglial tumors as the oligodendroglial group. The regions of interest with the maximum rCBV values within the tumors were normalized relative to the contra-lateral white matter (rCBVmax).

Results

The average rCBVmax of astrocytic tumors (2.01 ± 0.68) was significantly lower than that of the oligoastrocytic (4.60 ± 1.05) and oligodendroglial tumors (6.17 ± 0.867) (P < 0.0001). A cut-off value of 3.0 allowed to differentiate the oligodendroglial group from the astrocytic group at 100% sensitivity and 87.5% specificity.

Conclusion

The rCBVmax values obtained from 3 T MR PWI may be useful as an adjunct to the postoperative histopathological diagnosis of glioma patients.     

Magnetic resonance myocardial perfusion imaging-First experience at 3.0T

Objective

MR myocardial perfusion imaging (MRMPI) is an established technique for the evaluation of the hemodynamical relevance of coronary artery disease. Perfusion imaging at 3.0 T provides certain advantages compared to 1.5 T. Aim of this study was to evaluate myocardial MR perfusion imaging at 3.0 T.

Materials and methods

Twelve patients with stable Angina pectoris and known or suspected coronary artery disease were examined at 3.0 T. Myocardial perfusion was assessed using a saturation recovery gradient echo 2D sequence (TR 1.9 ms, TE 1.0 ms, FA 12°) with 0.05 mmol Gd-DTPA per kg body weight at stress during injection of 140 μg adenosine/kg body weight/min and at rest in short axis orientation. Perfusion analysis was based on a least square fit of the signal/time curve (peak signal intensity, slope). Perfusion series were assessed by two independent observers. Reference for the presence of relevant coronary artery stenoses was invasive coronary angiography. Two experienced observers evaluated the coronary angiograms in biplane projections for the presence and grade of stenoses. Results were compared with the MR perfusion analysis.

Results

All MR examinations could be safely performed and yielded high image quality. In eight patients stress-induced hypoperfusion was detected (stenosis >70% in coronary angiography). In four patients myocardial hypoperfusion was ruled out (stenosis <70%). The myocardial perfusion reserve index was significantly reduced in hypoperfused myocardium with 1.9 ± 1.6 compared to 2.5 ± 1.6 in regularly perfused myocardium (p < 0.05). In coronary angiography, eight patients were found to suffer from coronary artery disease, whereas in four patients coronary artery disease was ruled out.

Conclusion

Our initial results show that MRMPI at 3.0 T provides reliably high-image quality and diagnostic accuracy.