Single-dose gadolinium with magnetization transfer versus triple-dose gadolinium in the MR detection of multiple sclerosis lesions.

PURPOSETo compare the efficacy of single-dose gadolinium with magnetization transfer contrast (MTC) with that of triple-dose gadolinium in detecting enhancing multiple sclerosis lesions.METHODSTwenty-one patients with multiple sclerosis were examined with MR imaging first with 0.1 mmol/kg gadolinium (single dose) and then, after 24 to 72 hours, with 0.3 mmol/kg gadolinium (triple dose). T2-weighted fast spin-echo and T1-weighted spin-echo MR images with and without MTC were obtained before contrast administration followed by either T1-weighted spin-echo images with MTC (single dose) or conventional T1-weighted spin-echo images (triple dose), starting 5, 17, and 29 minutes after contrast administration. All images were evaluated in a blinded fashion and scored in random order by two readers. Outcome parameters included number of enhancing lesions, number of active MR examinations (those containing at least one enhancing lesion), contrast ratio (signal intensity of enhancing lesion divided by signal intensity of normal-appearing white matter), and size of enhancing lesions.RESULTSEighty-one percent more enhancing lesions and 49% more active MR examinations were detected when a triple dose of gadolinium was used as compared with a single dose. The level of agreement between readers as to the number of enhancing lesions was significantly higher for triple-dose than for single-dose gadolinium. With triple-dose gadolinium, contrast ratios and areas of enhancement increased by 10% and 33%, respectively. Delayed imaging increased the size of the lesion by 11% on single-dose MTC images and by 18% on triple-dose images.CONCLUSIONTriple-dose gadolinium is more effective (higher sensitivity and interobserver agreement) than single-dose gadolinium in combination with MTC in detecting enhancing multiple sclerosis lesions.     

The usefulness of MR in establishing the diagnosis of parotid pleomorphic adenoma.

PURPOSETo assess the usefulness of MR findings in establishing a specific diagnosis of parotid pleomorphic adenoma.METHODST1-weighted and T2-weighted MR images with and without contrast enhancement were obtained in 82 patients with parotid tumors. Imaging findings in the 38 patients in whom surgery subsequently revealed pleomorphic adenomas were compared with findings in the 44 patients who had other types of tumor. Specifically, the homogeneity, signal intensity, contrast enhancement, capsule thickness, lobulation, adenopathy, and infiltration of adjacent fat were compared among the different types of tumor. The sensitivity, specificity, positive predictive value, and negative predictive value were calculated.RESULTSA low-signal capsule on T2-weighted images and a lobulated contour characterized most pleomorphic adenomas. The sensitivity of the first finding for pleomorphic adenoma was 82%; specificity, 85%; positive predictive value, 82%; and negative predictive value, 84%. For the second finding, the sensitivity was 53%; specificity, 84%; positive predictive value, 74%; and negative predictive value, 67%.CONCLUSIONNone of the signs evaluated had perfect sensitivity and specificity. The MR findings of a complete capsule, lobulated contour, or high T2 signal intensity have a high predictive value for the diagnosis of pleomorphic adenoma.     

MR in temporal lobe epilepsy: analysis with pathologic confirmation.

PURPOSEWe evaluated the MR findings in patients with temporal lobe epilepsy to determine the predictive value of MR imaging in assessing patient outcome.METHODSMR studies from 186 of 274 consecutive patients who underwent temporal lobectomy for intractable epilepsy were reviewed retrospectively. Images were interpreted by an experienced neuroradiologist, who was blinded to the side of seizure activity and to pathologic findings.RESULTSMR imaging exhibited 93% sensitivity and 83% specificity in detecting hippocampal/amygdalar abnormalities (n = 121), and 97% sensitivity and 97% specificity in detecting abnormalities in the rest of the temporal lobe (n = 60). Abnormal high signal of the hippocampus on T2-weighted images had a sensitivity of 93% and specificity of 74% in predicting mesial temporal sclerosis (n = 115). The presence of hippocampal atrophy on MR correlated with the duration of seizures. Sensitivity and specificity of MR imaging in detecting temporal lobe tumors (n = 42) were 83% and 97%, respectively, based on abnormal signal and mass effect. After surgery, 63% of patients were seizure free and 28% had a significant reduction of seizure frequency at an average of 24 months (range, 12 to 78 months) after surgery. Patients with a single lesion in the anterior temporal lobe or hippocampus/amygdala had a better outcome than patients with multiple lesions (n = 22). Interrater agreement varied from 0.4 to 0.93, with best agreement for tumors or abnormal hippocampal signal on T2-weighted images.CONCLUSIONMR imaging is highly sensitive in detecting and locating abnormalities in the temporal lobe and the hippocampus/amygdala in patients with temporal lobe epilepsy. Hippocampal atrophy appears to correspond to the duration of seizure disorder.     

Rathke cleft cysts: correlation of enhanced MR and surgical findings.

PURPOSETo describe the gadolinium-enhanced MR findings of Rathke cleft cyst correlate them with the surgical findings, and define those preoperative findings that differentiate this lesion from other sellar and juxtasellar tumors.METHODSWe studied 18 patients who were diagnosed as having Rathke cleft cyst pathologically. These patients were imaged with T1- and T2-weighted coronal and sagittal spin-echo sequences. Fifteen of these patients received gadopentetate dimeglumine.RESULTSIn eight patients, the cyst showed low intensity on T1-weighted images and high intensity on T2-weighted images. At surgery, the cyst fluid was cerebrospinal fluid-like or light brown in five patients, motor oil-like in one patient, and milky in two patients. In 10 patients, cysts showed isointensity to high intensity on T1-weighted images and had various intensity on T2-weighted images. All 10 contained milky fluid. In three patients the intensity of fluid was heterogeneous. A waxy nodule was found in two patients. The position of the normal pituitary gland confirmed by surgery in all cases coincided with enhancement on MR imaging. The variable position of the normal pituitary gland was clearly identified in the sagittal images. The cyst walls showed no enhancement by gadopentetate dimeglumine.CONCLUSIONSBecause Rathke cleft cysts show variable intensities on MR, the diagnosis is often difficult when based on MR signal intensity values alone. MR imaging with gadopentetate dimeglumine does assist in the diagnosis of Rathke cleft cysts. Diagnostic clues include the lack of cyst wall enhancement and displacement of the normal pituitary gland.     

Detection of acoustic schwannoma: use of constructive interference in the steady state three-dimensional MR.

PURPOSETo compare constructive interference in the steady state (CISS) three-dimensional Fourier transform (3DFT) MR imaging with contrast-enhanced T1-weighted spin-echo MR imaging for accuracy in detecting acoustic schwannoma.METHODSOne hundred twenty-five consecutive patients with possible acoustic schwannoma were examined. The accuracy of CISS-3DFT MR imaging in detecting abnormalities of the cerebellopontine angle, the internal auditory canal, and the inner ear was compared with T1-weighted contrast-enhanced spin-echo MR imaging by independent assessment of both image sets by two observers.RESULTSThe postcontrast T1-weighted MR images revealed 18 cases of unilateral disease of the cerebellopontine angle and/or the internal auditory canal and no case of an abnormal bilateral cerebellopontine angle and/or internal auditory canal. Twelve cases were pathologically proved acoustic schwannomas. One meningioma of the cerebellopontine angle and one metastatic ependymoma to the cerebellopontine angle and the internal auditory canal was encountered. The four remaining cases had a provisional diagnosis of acoustic schwannoma and were scheduled for follow-up imaging and clinical review. Analysis of whether contrast material would have been administered to the appropriate patients (ie, those with disease of the cerebellopontine angle and/or internal auditory canal) according to CISS MR imaging findings revealed a sensitivity of 100% and a specificity of 98% for observer 1 and a sensitivity of 94% and a specificity of 94% for observer 2.CONCLUSIONCISS-3DFT MR imaging, in this patient population, provided high sensitivity and specificity in detecting lesions of the cerebellopontine angle and internal auditory canal; however, further experience is required before a definitive statement regarding the suitability of this technique as a screening procedure can be made. When contrast material cannot be administered, CISS MR imaging may be considered an adequate examination for the evaluation of possible acoustic schwannoma.     

The role of multi-parametric MR imaging in the detection of early inflammatory sacroiliitis according to ASAS criteria

Purpose

To retrospectively evaluate the accuracy of multi-parametric magnetic resonance (MR) imaging including fat saturated (FS) T2-weighted, short-tau inversion recovery (STIR), diffusion-weighted (DW-MR), and dynamic-contrast-enhanced MR (DCE-MR) imaging techniques in the diagnosis of early inflammatory sacroiliitis and determine the additional value of DW-MR and DCE-MR images according to recently defined ‘Assessment in SpondyloArthritis international Society’ criteria.

Materials and methods

The study included 45 patients with back pain. Two radiologists estimated the likelihood of osteitis in 4 independent viewing sessions including FS T2-weighted, STIR, DW-MR and DCE-MR images. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the receiver operating characteristic (ROC) curve (AUC) were calculated.

Results

Of the 45 patients, 31 had inflammatory back pain. Of 31, 28 (90.3%) patients had inflammatory sacroiliitis diagnosed by clinical and laboratory analysis. FS T2-weighted MR images had the highest sensitivity (42.8% for both radiologists) for detecting osteitis in patients with inflammaory sacroiliitis when compared to other imaging sequences. For specificity, PPV, NPV, accuracy, and AUC levels there were no statistically significant difference between image viewing settings. However, adding STIR, DW-MR and DCE-MR images to the FS T2-weighted MR images did not improve the above stated indices.

Conclusion

FS T2-weighted MR imaging had the highest sensitivity when compared to other imaging sequences. The addition of DW-MR and DCE-MR images did not significantly improve the diagnostic value of MR imaging in the diagnosis of osteitis for both experienced and less experienced radiologists.     

Clinical,neurodiagnostic, and MR findings in children with spinal and brain stem multiple sclerosis.

PURPOSETo describe the clinical, neurodiagnostic, and MR findings in seven children with brain stem and spinal multiple sclerosis.METHODSSpinal or brain stem multiple sclerosis was diagnosed in seven children between 1986 and 1992. All patients had neurologic and MR examinations as well as neurodiagnostic testing, including spinal fluid analysis and brain stem and auditory evoked potentials.RESULTSThree children had clinical findings and masslike lesions in the brain stem (two) or spinal cord (one) suggestive of neoplasm, which prompted biopsy (two) or radiation therapy (one). Five of six patients with spinal involvement had cord swelling with increased signal on T2-weighted images over at least three cord segments, and two children had essentially holocord involvement. Three children had normal cranial MR at presentation.CONCLUSIONSMultiple sclerosis involvement of the brain stem and spinal cord may be associated with extensive swelling and MR signal changes suggestive of neoplasm without typical cerebral white matter abnormalities. Serial clinical and neuroimaging examinations may be necessary to make a definitive diagnosis of multiple sclerosis in children.     

MR imaging evaluation of the activity of Crohn's disease.

OBJECTIVE: The purpose of this study was to evaluate the sensitivity and specificity of MR imaging in assessing the activity of Crohn's disease. SUBJECTS AND METHODS: Thirty symptomatic patients with Crohn's disease but uncertain disease activity were prospectively examined using MR imaging. Twenty-nine patients were scored using the Crohn's disease activity index. Six hundred milliliters of water orally and 1 mg of glucagon intramuscularly were given before imaging. Breath-hold images were obtained using T2-weighted turbo spin-echo, T1-weighted fast low-angle shot, and fat-suppressed gadolinium-enhanced T1-weighted fast low-angle shot sequences. Images were assessed by two radiologists who were unaware of the patient's symptoms, clinical scoring, and other imaging tests, and who reached a consensus about the imaging findings (bowel wall thickening, bowel wall enhancement, and perienteric changes) and determined the absence or presence of active disease in each patient. MR imaging findings were correlated with endoscopy and surgery. RESULTS: Twenty-three patients had active disease and seven patients had inactive disease. One hundred twenty-four of a total of 168 bowel segments were examined with both MR imaging and endoscopy or surgery. On a per patient basis, MR imaging had an overall sensitivity of 91% and a specificity of 71% for active disease. The Crohn's disease activity index had a sensitivity of 92% and a specificity of 28%. On a per segment basis, MR imaging had a sensitivity of 59% and a specificity of 93%. Bowel wall thickening of greater than 4 mm, bowel wall enhancement (ratio of signal intensity of abnormal to normal bowel > 1.3:1), and increased mesenteric vascularity were useful in identifying active disease. A layered enhancement pattern after the IV administration of gadolinium was highly specific for active inflammation. CONCLUSION: MR imaging is useful in assessing the activity of Crohn's disease and may be helpful when clinical scoring is equivocal.     

Differentiation of multiple sclerosis from other inflammatory disorders and cerebrovascular disease: value of spinal MR imaging

PURPOSE: To determine the value of magnetic resonance (MR) imaging in the spinal cord to differentiate multiple sclerosis (MS) from other inflammatory disorders and cerebrovascular diseases (together, other neurologic disease [OND]). MATERIALS AND METHODS: The study population included 66 patients with OND and 25 patients with MS, who were matched for age, sex, and symptom duration or severity. Brain MR imaging included gadolinium-enhanced T1-weighted and dual-echo T2-weighted spin-echo sequences to assess the number, size, and appearance of lesions, contrast enhancement, and compatibility with diagnostic criteria for MS. Spinal cord MR imaging included cardiac-triggered gadolinium-enhanced sagittal T1-weighted spin-echo and dual-echo T2-weighted sequences to assess the general appearance (normal, focal lesion, diffuse abnormality) and number or size of focal lesions. Images obtained in MS and OND patients were compared. Specificity, sensitivity, accuracy, and positive and negative predictive values with MR images were calculated. RESULTS: Brain images were abnormal in all MS patients and in 65% of OND patients. Abnormal cord images were found in 92% of MS and 6% of OND patients. The combination of brain and spinal cord images increased accuracy of diagnosis compared with use of brain images alone. CONCLUSION: In contrast to MS, cord lesions are very uncommon in OND. This finding can help differentiate these disorders.     

Detection of breast malignancy: diagnostic MR protocol for improved specificity

PURPOSE: To prospectively determine if a combined magnetic resonance (MR) protocol that includes T1-weighted dynamic contrast agent-enhanced (DCE) MR imaging, hydrogen 1 (1H) MR spectroscopy, and T2*-weighted perfusion MR imaging improves specificity in the diagnosis of breast cancer. MATERIALS AND METHODS: The combined MR imaging-MR spectroscopy protocol was performed in 50 patients after positive findings at mammography but prior to biopsy. Single-voxel proton MR spectroscopy and perfusion MR imaging were conducted only if DCE MR images showed rapid contrast enhancement in the lesion. Biopsy results were used as the reference for comparison with MR results and for calculation of sensitivity and specificity in the detection of breast malignancy. RESULTS: DCE MR imaging alone showed 100% sensitivity and 62.5% specificity. The specificity improved to 87.5% with the addition of 1H MR spectroscopy and to 100% with the further addition of perfusion MR imaging. Twenty-eight patients underwent both MR spectroscopy and perfusion MR imaging. Two patients underwent MR spectroscopy but declined to undergo perfusion MR imaging. The remaining 20 patients had negative results at DCE MR imaging and therefore did not undergo the additional examinations. CONCLUSION: The combined MR protocol of DCE MR imaging, 1H MR spectroscopy, and perfusion MR imaging has high sensitivity and specificity in the diagnosis of breast cancer.     

Magnetization transfer effects in MR-detected multiple sclerosis lesions: comparison with gadolinium-enhanced spin-echo images and nonenhanced T1-weighted images.

PURPOSETo define the relationship between magnetization transfer and blood-brain-barrier breakdown in multiple sclerosis lesions using gadolinium enhancement as an index of the latter.METHODSTwo hundred twenty lesions (high-signal abnormalities on T2-weighted images) in 35 multiple sclerosis patients were studied with gadolinium-enhanced spin-echo imaging and magnetization transfer. Lesions were divided into groups having nodular or uniform enhancement, ring enhancement, or no enhancement after gadolinium administration. For 133 lesions, T1-weighted images without contrast enhancement were also analyzed. These lesions were categorized as isointense or hypointense based on their appearance on the unenhanced T1-weighted images.RESULTSThere was no difference between the magnetization transfer ratio (MTR) of lesions as a function of enhancement. MTR of hypointense lesions on unenhanced T1-weighted images was, however, lower than the MTR of isointense lesions.CONCLUSIONWe speculate that diminished MTR may reflect diminished myelin content and that hypointensity on T1-weighted images corresponds to demyelination. Central regions of ring-enhancing lesions had a lower MTR than the periphery, suggesting that demyelination in multiple sclerosis lesions occurs centrifugally. In addition, the short-repetition-time pulse sequence seems useful in the evaluation of myelin loss in patients with multiple sclerosis.     

Rheumatoid arthritis of the knee: value of gadopentetate dimeglumine-enhanced MR imaging

In an attempt to differentiate among joint effusion, synovitis, pannus, and subchondral sclerosis in patients with clinically proved chronic rheumatoid arthritis, we used gadopentetate dimeglumine-enhanced MR imaging to examine 23 patients with acute knee symptoms. All patients had had rheumatoid arthritis for more than 6 months and satisfied four or more of the criteria of the American Rheumatism Association for rheumatoid arthritis. MR imaging was performed on a 1.5-T machine by using unenhanced T1-weighted spin-echo imaging, unenhanced T2*-weighted gradient-echo imaging, and unenhanced and enhanced T1-weighted gradient-echo imaging. Signal intensities of the synovium and bone marrow were measured with the region-of-interest technique on unenhanced and enhanced T1-weighted gradient-echo scans. Conventional radiographs were available for each patient. Joint effusion, synovitis, intraarticular pannus, subchondral sclerosis, and subchondral pannus had the same signal intensities on unenhanced T1-weighted spin-echo, unenhanced T1-weighted gradient-echo, and unenhanced T2*-weighted gradient-echo MR images, and could not be differentiated from one another. On enhanced T1-weighted gradient-echo sequences, pannus and synovitis showed marked enhancement in 15 patients, whereas joint effusion and sclerosis did not. Synovitis was diagnosed if the synovial membrane showed high enhancement; pannus was diagnosed if enhancing masses were seen within the joint space or in the subchondral area. In eight of the 23 joints, there was no enhancement of the synovium or intraarticular or subchondral tissue. We conclude that gadopentetate dimeglumine-enhanced MR imaging allows differentiation between synovitis and joint effusion and between subchondral pannus and subchondral sclerosis. Enhancement of the synovium and pannus indicates acute inflammation of the joint.     

Low-cost high-resolution fast spin-echo MR of acoustic schwannoma: an alternative to enhanced conventional spin-echo MR?

PURPOSETo determine whether unenhanced high-resolution T2-weighted fast spin-echo MR imaging provides an acceptable and less expensive alternative to contrast-enhanced conventional T1-weighted spin-echo MR techniques in the diagnosis of acoustic schwannoma.METHODSWe reviewed in a blinded fashion the records of 25 patients with pathologically documented acoustic schwannoma and of 25 control subjects, all of whom had undergone both enhanced conventional spin-echo MR imaging and unenhanced fast spin-echo MR imaging of the cerebellopontine angle/internal auditory canal region. The patients were imaged with the use of a quadrature head receiver coil for the conventional spin-echo sequences and dual 3-inch phased-array receiver coils for the fast spin-echo sequences.RESULTSThe size of the acoustic schwannomas ranged from 2 to 40 mm in maximum dimension. The mean maximum diameter was 12 mm, and 12 neoplasms were less than 10 mm in diameter. Acoustic schwannoma was correctly diagnosed on 98% of the fast spin-echo images and on 100% of the enhanced conventional spin-echo images. Statistical analysis of the data using the kappa coefficient demonstrated agreement beyond chance between these two imaging techniques for the diagnosis of acoustic schwannoma.CONCLUSIONSThere is no statistically significant difference in the sensitivity and specificity of unenhanced high-resolution fast spin-echo imaging and enhance T1-weighted conventional spin-echo imaging in the detection of acoustic schwannoma. We believe that the unenhanced high-resolution fast spin-echo technique provides a cost-effective method for the diagnosis of acoustic schwannoma.     

Spinal cord lesions in patients with multiple sclerosis: comparison of MR pulse sequences.

PURPOSETo compare T2-weighted conventional spin-echo (CSE), fast spin-echo (FSE), shorttau inversion recovery (STIR) FSE, and fluid-attenuated inversion recovery (FLAIR) FSE sequences in the assessment of cervical multiple sclerosis plaques.METHODSTwenty patients with clinically confirmed multiple sclerosis and signs of cervical cord involvement were examined on a 1.5-T MR system. Sagittal images of T2-weighted and proton density-weighted CSE sequences, T2-weighted FSE sequences with two different sets of sequence parameters, STIR-FSE sequences, and FLAIR-FSE sequences were compared by two independent observers. In addition, contrast-to-noise measurements were obtained.RESULTSSpinal multiple sclerosis plaques were seen best on STIR-FSE images, which yielded the highest lesion contrast. Among the T2-weighted sequences, the FSE technique provided better image quality than did the CSE technique, but lesion visibility was improved only with a repetition time/echo time of 2500/90; parameters of 3000/150 provided poor lesion contrast but the best myelographic effect and overall image quality. CSE images were degraded by prominent image noise; FLAIR-FSE images showed poor lesion contrast and strong cerebrospinal fluid pulsation artifacts.CONCLUSIONSThe STIR-FSE sequence is the best choice for assessment of spinal multiple sclerosis plaques. For T2-weighted FSE sequences, shorter echo times are advantageous for spinal cord imaging, long echo times are superior for extramedullary and extradural disease. FLAIR-FSE sequences do not contribute much to spinal imaging for multiple sclerosis detection.     

Evaluation of sclerosis in Modic changes of the spine using susceptibility-weighted magnetic resonance imaging

PurposeTo evaluate the diagnostic performance of susceptibility-weighted magnetic resonance imaging (SWMR) for the differentiation of sclerotic and non-sclerotic Modic changes (MC) of the spine compared to computed tomography (CT) and radiographs.Materials and methodsThe Institutional Ethics-Review-Board approved this prospective study in advance. Written consent was obtained from all subjects. SWMR and standard T1/T2 MR of the cervical (n = 21) and/or lumbar spine (n = 34) were performed in 54 patients. 21 patients served as control. 18 patients were evaluated with CT; in all other patients radiographs were available. 67 Modic changes were identified on T1/T2 MR. On SWMR changes were classified as sclerotic and non-sclerotic based on signal intensity measurements. The sensitivity and specificity of SWMR and T1/T2 MR for differentiating between sclerotic and non-sclerotic Modic changes were determined with CT and radiographs as reference standard.ResultsOn SWMR, signal measurements between sclerotic and non-sclerotic Modic changes differed significantly (p < 0.01). On T1- and T2-weighted MR no significant difference (p > 0.05) was measured. On SWMR, a reliable differentiation between sclerotic and non-sclerotic Modic changes could be achieved, with a sensitivity of 100% and specificity of 95%. In contrast, the combination of T1-/T2-weighted MR yielded a significantly lower sensitivity to detect sclerosis (20%).ConclusionSWMR allows a reliable detection of sclerosis in Modic changes with a higher accuracy compared to standard spine MR sequences, using radiographs and CT as reference standard.     

Contrast-enhanced magnetization transfer MR of the brain: importance of precontrast images.

PURPOSETo determine the importance of obtaining precontrast T1-weighted magnetization transfer (MT) MR images for better interpretation contrast-enhanced T1-weighted MT images.METHODSOne hundred fifty-five patients referred for MR imaging of the brain were examined prospectively with noncontrast T1-weighted imaging, noncontrast T1-weighted imaging with MT, contrast-enhanced T1-weighted imaging, and contrast-enhanced T1-weighted imaging with MT. In the patients who had abnormally increased signal intensity on postcontrast images (with or without MT), the four imaging sequences were evaluated with regard to number of lesions and lesional signal intensity. For each of the sequences, two experienced neuroradiologists subjectively graded the lesions on a scale of 1 to 4 (4 being the most conspicuous) with regard to abnormally increased signal intensity.RESULTSTwenty-two of the 155 patients had increased signal intensity on one or more of the postcontrast sequences. Eight of these 22 patients had increased signal intensity of one or more lesions on images without MT. All these lesions were seen better on images obtained with MT. An additional six of the 22 patients had increased signal intensity of one or more lesions on images obtained with MT that was not detected on images obtained without MT. Eight of the 22 patients had no high signal intensity on noncontrast images with or without MT. One of the eight had increased number and conspicuity of lesions on postcontrast MT images.CONCLUSIONSA significant number of patients had increased signal intensity on noncontrast T1-weighted images with MT that was not seen on noncontrast T1-weighted images without MT. This high signal intensity was also visible on postcontrast MT images, and would have been mistaken for pathologic enhancement if noncontrast MT images had not been available for comparison.     

Clinical utility of susceptibility-weighted MR sequence for the evaluation of uterine sarcomas

PurposeHigh intensity intra-tumoral hemorrhagic necrosis on T1-weighted images is a suggestive finding for uterine sarcomas, however, the reported prevalence varies. The purpose of this study is to evaluate the capability of susceptibility-weighted MR sequences (SWS) for the diagnosis of uterine sarcomas.Materials and methodsMR imaging of surgically proven 10 uterine sarcomas and 24 benign leiomyomas were retrospectively evaluated for the presence of high intensity areas on T1-weighted images and signal voids on SWS (T2 star-weighted angiography: SWAN).ResultsHigh intensity areas on T1-weighted images and signal voids on SWS were observed in 40% and 100% of sarcomas, whereas 0% and 4% of leiomyomas, respectively. The accuracy, sensitivity, and specificity for T1-weighted images were 82%, 40%, and 100%, and for SWS were 97%, 100%, and 96%, respectively.ConclusionThe demonstration of intra-tumoral hemorrhage in patients suspected with uterine sarcomas by SWS may provide valuable diagnostic findings.     

MR evaluation of frontal sinus osteoplastic flaps with autogenous fat grafts.

PURPOSETo investigate the MR findings in patients who have had osteoplastic frontal sinus flaps placed for inflammatory sinonasal disease.METHODSThe MR images of 13 patients who had improvement of symptoms after osteoplastic frontal sinus flap placement with fat autograft were prospectively evaluated for the presence of high intensity on T2-weighted scans, contrast enhancement, and replacement of frontal sinus fat by lower-signal soft tissue. All studies were performed on a 1.5-T unit using a 5-in round surface coil placed over the nasion. Sagittal T1-weighted, axial and coronal fast spin-echo T2-weighted, and precontrast and postcontrast axial and coronal T1-weighted images were obtained through the operative bed. The T2-weighted and postgadolinium sequences were done with a fat-suppression technique.RESULTSHyperintensity within the frontal sinuses on T2-weighted images and enhancement (peripherally and/or centrally where fat was replaced with soft tissue) were found to some degree in all patients. The degree of replacement of frontal sinus fat with soft tissue ranged from 4% to 85% (mean, 43%). Five patients with persistent symptoms had no distinguishing MR features when compared with asymptomatic patients.CONCLUSIONSAlthough increased T2-weighted intensity, fat replacement, and enhancement are findings compatible with inflammation, these changes may be seen in patients who are asymptomatic after placement of osteoplastic frontal sinus flaps; they may represent the normal granulation process. MR findings after flap placement are nonspecific and have limited utility in distinguishing symptomatic patients with recurrent inflammatory disease from asymptomatic patients whose imaging findings are related to postoperative scar tissue.     

Multimodality MR imaging assessment of myocardial viability: combination of first-pass and late contrast enhancement to wall motion dynamics and comparison with FDG PET-initial experience

PURPOSE: To combine three magnetic resonance (MR) imaging modalities-dobutamine stress cine, first pass, and late contrast material-enhanced T1-weighted imaging-and to compare the results with 2-[fluorine 18]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) in the assessment of unviable myocardium in coronary artery disease. MATERIALS AND METHODS: Ten patients with multivessel coronary artery disease underwent MR imaging before and 6 months after bypass surgery. Left ventricular cine MR imaging was performed at rest and during dobutamine infusion. Inversion-recovery gradient-echo images were obtained to study myocardial contrast enhancement at first pass and 5 minutes later. FDG PET was performed with orally administered acipimox before surgery. RESULTS: With dobutamine cine MR imaging, unviable myocardium was detected with a sensitivity of 79% and a specificity of 93%; postoperative wall thickening was the standard. First-pass analysis increased these values to 97% and 96%; analysis of late enhancement with T1-weighted imaging, to 62% and 98%. FDG PET had a sensitivity of 81% and a specificity of 86%. CONCLUSION: The combination of first-pass enhancement analysis and wall motion assessment with stress significantly increases the specificity of MR imaging in the detection of unviable sectors.     

Deep Learning Based on MR Imaging for Predicting Outcome of Uterine Fibroid Embolization

PurposeTo develop and validate a deep learning model based on routine magnetic resonance (MR) imaging obtained before uterine fibroid embolization to predict procedure outcome.Materials and MethodsClinical data were collected on patients treated with uterine fibroid embolization at the Hospital of the University of Pennsylvania from 2007 to 2018. Fibroids for each patient were manually segmented by an abdominal radiologist on a T1-weighted contrast-enhanced (T1C) sequence and a T2-weighted sequence of MR imaging obtained before and after embolization. A residual convolutional neural network (ResNet) model to predict clinical outcome was trained using MR imaging obtained before the procedure.ResultsInclusion criteria were met by 727 fibroids in 409 patients. At clinical follow-up, 85.6% (n = 350) of 409 patients (590 of 727 fibroids; 81.1%) experienced symptom resolution or improvement, and 14.4% (n = 59) of 409 patients (137 of 727 fibroids; 18.9%) had no improvement or worsening symptoms. The T1C trained model achieved a test accuracy of 0.847 (95% confidence interval [CI], 0.745–0.914), sensitivity of 0.932 (95% CI, 0.833–0.978), and specificity of 0.462 (95% CI, 0.232–0.709). In comparison, the average of 4 radiologists achieved a test accuracy of 0.722 (95% CI, 0.609–0.813), sensitivity of 0.852 (95% CI, 0.737–0.923), and specificity of 0.135 (95% CI, 0.021–0.415).ConclusionsThis study demonstrates that deep learning based on a ResNet model achieves good accuracy in predicting outcome of uterine fibroid embolization. If further validated, the model may help clinicians better identify patients who can most benefit from this therapy and aid clinical decision making.