Dynamic helical CT of T1 and T2 glottic carcinomas: predictive value for local control with radiation therapy

BACKGROUND AND PURPOSE: Tumor volume and cartilage invasion have been suggested as prognostic factors of glottic carcinomas following definitive radiation therapy. Radiologic examinations provide additional information regarding the deep extension of tumor. We determined whether dynamic helical CT can predict local control of early (T1 and T2 stage) glottic carcinomas treated with definitive radiation therapy. METHODS: Sixty-eight patients with early glottic carcinoma evaluated on pretreatment dynamic helical CT were treated with definitive radiation therapy. Tumor detectability, maximum dimension, tumor volume, and involvement of anatomic subsites (anterior commissure, ventricle, subglottic region, and thyroid and arytenoid cartilages) were determined by consensus by three radiologists without previous knowledge of the clinical information. The CT findings were correlated with local control. RESULTS: The two-year local control rate was 76%; 91% for T1 and 60% for T2 lesions. Univariate analysis revealed clinical T stage, tumor detectability, maximum dimension, tumor volume, anterior commissure involvement, ventricle involvement, and thyroid cartilage involvement as significant prognostic factors. Thyroid cartilage involvement was an independent predictor by multivariate analysis. The lesions separate from the thyroid cartilage had a 95% probability of local control, whereas the lesions adjacent to the cartilage had only a 42% control rate. CONCLUSION: Dynamic helical CT provides prognostic information for the results of definitive radiation therapy. Patients with a tumor adjacent to the thyroid cartilage had an increased risk of local failure.     

The role of diffusion-weighted imaging and the apparent diffusion coefficient (ADC) values for breast tumors.

OBJECTIVE: We wanted to evaluate the role of diffusion-weighted imaging (DWI) and the apparent diffusion coefficient (ADC) for detecting breast tumors, as compared with the T1- and T2-weighted images. MATERIALS AND METHODS: Forty-one female patients underwent breast MRI, and this included the T1-, T2-, DWI and dynamic contrast-enhanced images. Sixty-five enhancing lesions were detected on the dynamic contrast-enhanced images and we used this as a reference image for detecting tumor. Fifty-six breast lesions were detected on DWI and the histological diagnoses were as follows: 43 invasive ductal carcinomas, one mucinous carcinoma, one mixed infiltrative and mucinous carcinoma, seven ductal carcinomas in situ (DCIS), and four benign tumors. First, we compared the detectability of breast lesions on DWI with that of the T1- and T2-weighted images. We then compared the ADCs of the malignant and benign breast lesions to the ADCs of the normal fibroglandular tissue. RESULTS: Fifty-six lesions were detected via DWI (detectability of 86.2%). The detectabilities of breast lesions on the T1- and T2-weighted imaging were 61.5% (40/65) and 75.4% (49/65), respectively. The mean ADCs of the invasive ductal carcinoma (0.89+/-0.18 x 10(-3)mm(2)/second) and DCIS (1.17+/-0.18 x 10(-3)mm(2)/ second) are significantly lower than those of the benign lesions (1.41+/-0.56 x 10(-3)mm(2)/second) and the normal fibroglandular tissue (1.51+/-0.29 x 10(-3)mm(2)/ second). CONCLUSION: DWI has a high sensitivity for detecting breast tumors, and especially for detecting malignant breast tumors. DWI was an effective imaging technique for detecting breast lesions, as compared to using the T1- and T2-weighted images.     

Dynamic gadolinium-enhanced MR imaging of the spleen: normal enhancement patterns and evaluation of splenic lesions

The authors studied the ability to improve detection of splenic lesions during suspended respiration with dynamic gadolinium-enhanced T1-weighted spin-echo magnetic resonance (MR) imaging. In the first phase of the study, normal splenic contrast material enhancement patterns were assessed in 10 control patients without splenic lesions. A heterogeneous signal intensity pattern was observed in 11 patients with splenic lesions during bolus injection of gadopentetate dimeglumine, with conversion to homogeneous enhancement 1 minute later. Mean splenic enhancement was 321% during bolus injection, with a rapid return toward baseline signal intensity thereafter. In the second phase, evaluation of 18 splenic lesions detected with contrast-enhanced computed tomography in 11 patients revealed that dynamic gadolinium-enhanced MR pulse sequences significantly improved lesion conspicuity and detectability compared with conventional T1-and T2-weighted pulse sequences. Contrast-to-artifact ratio measurements were 0.5, 3.7, and 9.3 for conventional T1-weighted, T2-weighted, and dynamic gadolinium-enhanced MR images, respectively.     

Dynamic T1-weighted spin-echo MR imaging: the role of digital subtraction in the demonstration of enhancing brain lesions

We compared subtracted and non-subtracted images obtained from a contrast-enhanced dynamic T1-weighted spin echo (SE) magnetic resonance (MR) technique for the demonstration of enhancing brain lesions with and without associated hemorrhage. Thirty-four patients with enhancing brain lesions or subacute parenchymal hematomas were imaged using a contrast-enhanced dynamic T1-weighted SE MR technique modified by a keyhole scheme. On-line digital subtraction was performed. Non-subtracted and subtracted dynamic scans were compared for conspicuity and contrast-to-noise ratios (CNRs) of enhancing brain lesions. The presence and pattern of enhancement in the subacute parenchymal hematomas were evaluated on the subtracted images. In all, 47 enhancing brain lesions were detected on both the non-subtracted and the subtracted images. The enhancing brain lesions were more conspicuous on the subtracted images (P < 0.05). There was an increase in CNRs of the enhancing lesions on the subtracted images compared with the non-subtracted ones (P < 0.001). Seventeen subacute parenchymal hematomas were detected on the non-subtracted images. The subtracted images demonstrated enhancement in 15 hematomas (8 rim enhancement only/7 both nodular and rim enhancement). Digital subtraction in contrast-enhanced dynamic T1-weighted SE MR imaging is helpful in demonstrating enhancing brain lesions with and without associated hemorrhage.     

Endometrial carcinoma: multisection dynamic MR imaging using a three-dimensional FLASH technique during breath holding.

PURPOSE: Our aim was to investigate the usefulness of multisection dynamic MR imaging using a 3D FLASH technique during breath holding in assessing myometrial invasion by endometrial carcinoma. MATERIALS AND METHODS: Twenty-eight endometrial carcinomas were evaluated with pathologic correlation. Dynamic MR imaging was performed using the 3D FLASH technique during breath holding. We compared accuracy in the assessment of myometrial invasion by endometrial carcinoma between T2-weighted images, contrast-enhanced T1-weighted images, and dynamic MR images. RESULTS: The accuracy rates in estimating myometrial invasion with T2-weighted images, contrast-enhanced T1-weighted images, and dynamic MR images were 64.3%, 67.8%, and 85.7%, respectively. Statistically significant differences were seen between dynamic MR images and both T2-weighted images and contrast-enhanced T1-weighted images. CONCLUSION: Multisection dynamic MR imaging using the 3D FLASH technique during breath holding is useful for the evaluation of myometrial invasion by endometrial carcinoma with polypoid growth or an unclear junctional zone on T2-weighted images.     

MR重T2W首次通过灌注成像鉴别乳腺良恶性肿瘤的价值初探

目的　评价在同 1次检查中T1W动态增强成像之后进行重T2 W (T 2 W )首次通过灌注成像的可行性 ,以及后者在鉴别乳腺良恶性肿瘤方面的诊断价值。方法　 2 9例乳腺病患者在T1W动态增强后进一步行病灶局部的T 2 W首次通过灌注成像 ,分别根据病灶T1W动态增强的早期强化程度和T 2 W首次通过灌注成像的早期信号丢失程度判定病灶的良恶性 ,计算其敏感度、特异度 ,以进行两方法间的比较。结果　应用T1W动态增强成像序列 ,良、恶性病变的信号强度增加率之间差异有显著性意义 (t=2 5 6 3,P =0 0 16 ) ,但两者的早期增强程度范围有很大的重叠 ;早期增强率诊断的敏感度为 94 % ,特异度仅为 2 5 %。应用T 2 W首次通过灌注成像序列 ,良、恶性病变之间的T2 信号强度丢失程度差异有非常显著性意义 (t=4 777,P <0 0 0 1) ,良、恶性病变的早期信号丢失率之间重叠很少 ;早期信号丢失率诊断的敏感度为 88% ,特异度为 75 %。结论　T 2 W首次通过灌注成像在鉴别良恶性乳腺肿瘤方面具有较高特异度 ;在同一患者中 ,T 2 W首次通过灌注成像结合T1W动态增强成像检查是可行的 ,可以提高乳腺MR成像的诊断准确性。     

MR imaging of pelvic masses in women: contrast-enhanced vs unenhanced images.

OBJECTIVE. We compared the value of contrast-enhanced MR images with that of T2-weighted MR images in the diagnosis and staging of pelvic masses in women. MATERIALS AND METHODS. The findings on preoperative MR studies of 97 patients with a total of 124 surgically proved lesions were retrospectively analyzed. Unenhanced T1- and T2-weighted spin-echo images were compared with contrast-enhanced T1-weighted images. The final diagnosis included benign (36 patients), borderline (six patients), and malignant (15 patients) ovarian masses, fallopian tube masses (15 patients), endometrial tumors (seven patients), cervical carcinomas (32 patients), subserous leiomyomas (11 patients), and two masses of extragenital origin. RESULTS. In the depiction of pelvic lesions, the sensitivity of contrast-enhanced MR imaging (96%) was equal to that of unenhanced T2-weighted imaging (97%). Contrast-enhanced images were useful in the definition of intratumoral architecture and tumor borders of 72 adnexal masses, resulting in better determination of malignancy (accuracy, 95%) than on T2-weighted images (85%). Size of viable tumor, differentiation of tumor from retained fluid, and depth of myometrial invasion of six endometrial carcinomas were most reliably shown on contrast-enhanced images. In the evaluation of cervical carcinoma, overall staging accuracy of contrast-enhanced imaging (80%) was slightly inferior to that of T2-weighted imaging (83%). However, contrast-enhanced images improved assessment of parametrial and organ invasion in seven cases in which findings on T2-weighted MR images were equivocal. Administration of contrast material was not helpful in the evaluation of subserous leiomyomas or masses of extragenital origin. CONCLUSIONS. The findings suggest that when results of unenhanced T1- and T2-weighted MR imaging of pelvic masses are equivocal, contrast-enhanced MR images should be used as supportive and complementary pulse sequences to (1) improve definition of intratumoral architecture and prediction of malignancy in adnexal tumors, (2) stage endometrial carcinoma, and (3) determine tumor extension in cervical carcinoma.     

Intracranial leptomeningeal metastases: comparison of depiction at FLAIR and contrast-enhanced MR imaging

PURPOSE: To compare contrast material-enhanced T1-weighted and fluid-attenuated inversion-recovery (FLAIR) magnetic resonance (MR) images in depicting leptomeningeal metastases. MATERIALS AND METHODS: Malignant lesions detected at cytologic examination of cerebrospinal fluid in 70 patients were reviewed. There were 58 studies in which both FLAIR and contrast-enhanced T1-weighted spin-echo MR images were available. A senior neuroradiologist reviewed the images from each sequence individually and separately for signs of leptomeningeal metastases and assigned a diagnostic rating of positive, indeterminate, or negative. RESULTS: Leptomeningeal metastases were depicted in 38 cases on contrast-enhanced T1-weighted spin-echo images and in 20 cases on FLAIR images. In three cases, leptomeningeal metastases were detected by using only FLAIR images. In 20 cases, leptomeningeal metastases were detected by using only contrast-enhanced T1-weighted spin-echo images. FLAIR imaging has a sensitivity of 34% for cytologically proved leptomeningeal metastases. Gadolinium-enhanced MR imaging has a sensitivity of 66%. CONCLUSION: Used alone, contrast-enhanced T1-weighted images are better than FLAIR images for detecting leptomeningeal metastases. This is particularly true for cases in which leptomeningeal metastases manifest primarily or solely as cranial nerve involvement.     

Irradiated carcinoma of the tongue: correlation of MR imaging findings with pathology

OBJECTIVE: MR imaging was prospectively correlated with pathologic findings to study whether MR imaging can differentiate viable from nonviable tumor tissue in the irradiated carcinoma of the tongue. SUBJECTS AND METHODS: MR examinations were performed after radiation therapy in 21 patients with carcinoma of the tongue. All patients underwent either a total glossectomy or hemiglossectomy after radiation therapy. Specimens were examined microscopically. Radiation changes were histologically graded into four groups (I, minimal cellular changes; II, presence of cellular changes and partial destruction of the tumor; III, only nonviable tumor cells; IV, no tumor cells). MR examinations included T2-weighted imaging, unenhanced T1-weighted imaging, dynamic contrast-enhanced imaging, and contrast-enhanced T1-weighted imaging. RESULTS: On unenhanced T1-weighted images, the lesion was hypointense, except for two patients with histologic grade III. On T2-weighted images, the lesion appeared hyperintense in 12 of 14 patients with viable tumor cells (grades I and II); however, the lesion was hypointense in four, and isointense in two of seven patients with nonviable tumor cells (grades III or IV). Contrast-enhanced T1-weighted images showed that the degree of contrast enhancement of the lesion was equal to or lower than that of a normal salivary gland in 18 of 21 patients. For the time of maximal enhancement of the lesion on dynamic imaging, there was no substantial difference between viable (grades I and II) and nonviable (grades III and IV) tumor tissue. CONCLUSION: The present study shows that T2-weighted imaging is feasible for differentiating viable from nonviable tumor tissue in irradiated carcinoma of the tongue.     

CT and MR imaging features of oral and maxillofacial hemangioma and vascular malformation

PURPOSE: To present CT and MR images and compare CT and MRI features of oral and maxillofacial hemangioma and vascular malformation. MATERIAL AND METHODS: The clinical materials consisted of nine vascular tumors from nine patients examined by both CT and MR scanners between November 1996 and March 2002. Both CT and MR images were retrospectively evaluated. The following features were evaluated: detectability of the lesion, border of the lesion, tumor margin, inner nature of the lesion, contrast between the lesion and surrounding tissues, degree of CT value or signal intensity of the lesion, enhancement of contrast medium, inner nature of the lesion after contrast medium injection, detectability of phleboliths and detectability of bone resorption. RESULTS: In two patients, we could not detect lesions in any of the CT images because of artifacts from the teeth and/or dental restorations. In contrast, we could detect all lesions on T2-weighted MR images and contrast enhanced T1-weighted MR images. On T2-weighted images with the fat suppression technique, tumors tended to show higher contrast compared to surrounding tissues. CONCLUSION: T2-weighted images with the fat suppression technique and contrast enhanced T1-weighted images with the fat suppression technique were very useful for the detection of vascular lesions. Observation from optional directions (axial, coronal and sagittal images) seemed appropriate for delineating the extension of the tumor. Phleboliths detectability on CT images was superior to that on MR images.     

Breast lesions: evaluation with dynamic contrast-enhanced T1-weighted MR imaging and with T2*-weighted first-pass perfusion MR imaging

PURPOSE: To evaluate the diagnostic value of an imaging protocol that combines dynamic contrast-enhanced T1-weighted magnetic resonance (MR) imaging and T2*-weighted first-pass perfusion imaging in patients with breast tumors and to determine if T2*-weighted imaging can provide additional diagnostic information to that obtained with T1-weighted imaging. MATERIALS AND METHODS: One hundred thirty patients with breast tumors underwent MR imaging with dynamic contrast-enhanced T1-weighted imaging of the entire breast, which was followed immediately with single-section, T2*-weighted imaging of the tumor. RESULTS: With T2*-weighted perfusion imaging, 57 of 72 carcinomas but only four of 58 benign lesions had a signal intensity loss of 20% or more during the first pass, for a sensitivity of 79% and a specificity of 93%. With dynamic contrast-enhanced T1-weighted imaging, 64 carcinomas and 19 benign lesions showed a signal intensity increase of 90% or more in the first image obtained after the administration of contrast material, for a sensitivity of 89% and a specificity of 67%. CONCLUSION: T2*-weighted first-pass perfusion imaging can help differentiate between benign and malignant breast lesions with a high level of specificity. The combination of T1-weighted and T2*-weighted imaging is feasible in a single patient examination and may improve breast MR imaging.     

Endometrial carcinoma in adenomyosis: assessment of myometrial invasion on T2-weighted spin-echo and gadolinium-enhanced T1-weighted images

OBJECTIVE: The aim of our study was to compare T2-weighted and contrast-enhanced dynamic T1-weighted images with histologic findings in assessing the depth of myometrial invasion by endometrial carcinoma in adenomyosis. MATERIALS AND METHODS: We retrospectively reviewed the MRIs of 11 patients who had a total of 12 lesions of endometrial carcinoma within adenomyosis. T2-weighted and contrast-enhanced dynamic T1-weighted images were compared with the histologic findings separately. We assessed the extent of myometrial invasion by endometrial carcinomas. The depth of myometrial invasion seen on MRI was classified as stage S (superficial invasion), stage D (deep invasion), or undetectable. The staging accuracies of each sequence were assessed. The tumor-myometrium contrast-to-noise ratios were calculated for each sequence. RESULTS: The histologic specimens revealed that myometrial invasion was deep in seven of 12 lesions and superficial in five. On T2-weighted images the depth of invasion was underestimated in two lesions and impossible to determine in five lesions. On dynamic T1-weighted images the depth of invasion was overestimated in one lesion and underestimated in one lesion. The staging accuracy on dynamic T1-weighted images (83%) was significantly higher than that on T2-weighted images (42%). The contrast-to-noise ratio was significantly higher on dynamic T1-weighted studies during the early phase (mean +/- SD, 2.68 +/- 0.94) than it was on T2-weighted studies (1.74 +/- 1.05) and during the delayed phase (2.01 +/- 0.86). CONCLUSION: When adenomyosis coexists with endometrial cancer at the same site on T2-weighted images, contrast-enhanced dynamic T1-weighted imaging improves the accuracy of staging.     

Analysis of patellar cartilage. Comparison of conventional MR imaging and MR and CT arthrography in cadavers

Objective: To compare the sensitivity of conventional MR sequences, MR arthrography, and CT arthrography for the detection of cartilage lesions of the patella in cadavers.Material and Methods: Cartilage lesions in 10 cadaveric specimens were evaluated by MR imaging, including T1-weighted, proton density-weighted and T2-weighted sequences, and fat-suppressed spoiled gradient recalled acquisition in the steady state (SPGR), MR arthrography including T1-weighted and SPGR sequences, and double-contrast CT arthrography including conventional and subtracted images. The sensitivities with regard to detection of lesions were compared to results from morphologic and histologic investigations of sectioned specimens.Results: Twenty-one lesions were detected morphologically. For the detection of these lesions, sensitivities were as follows: T1-weighted images 33.3%; proton density-weighted images 85.7%; T2-weighted images 85.7%; SPGR images 80.9%; MR arthrography with T1-SE sequences 57.1%; MR arthrography with SPGR sequence 90.5%; and CT arthrography, both regular and subtracted images 85.7%.Conclusion: For noninvasive techniques, T2-weighted images revealed the highest sensitivity for the detection of patellar cartilage lesions, which was surpassed only by MR arthrography using the SPGR sequence. CT arthrography delineated surface irregularities but failed to demonstrate intrachondral lesions.     

Magnetic resonance imaging in suspected rectal cancer: determining tumor localization, stage, and sphincter-saving resectability at 3-Tesla-sustained high resolution

Purpose: To assess image quality and overall accuracy of 3-Tesla (3T)-sustained high-resolution magnetic resonance (MR) imaging for diagnostic preoperative workup in suspected rectal carcinoma.

Material and Methods: Twenty-three patients with suspected rectal cancer underwent unenhanced and contrast-enhanced fat-suppressed pelvic high-resolution MR imaging using a four-channel phased-array pelvic coil at 3T. Image quality, tumor stage, distance from the anorectal margin, and sphincter-saving resectability were prospectively assessed by two blinded readers. The results were correlated with clinical, surgical, and histopathologic findings.

Results: In all 23 patients, MR images were of diagnostic quality, and malignancy was correctly identified in 21 patients. The accuracy for determining sphincter-saving resectability was 100% (19/19). T stage and N stage were correctly diagnosed in 95% and 91%, respectively. MRI allowed correct identification of tumor extension and its relation to surgically relevant pelvic structures including the anorectal margin and mesorectal fascia. Transverse T2-weighted fast spin-echo images compared superiorly to all other sequences for the diagnosis of mesorectal infiltration and lymph node involvement. Moreover, transverse fat-suppressed contrast-enhanced T1-weighted images were valuable for identifying tumor infiltration, while sagittal sections were useful for the detection of longitudinal tumor extension.

Conclusion: MR imaging with phased-array receiver coils at 3T facilitated both visualization of different pathologic conditions of the rectum and accurate determination of tumor stage in rectal carcinomas. Thus, this noninvasive diagnostic approach appeared highly suitable for the assessment of patients with suspected rectal carcinoma.     

Contrast-enhanced T1-weighted fluid-attenuated inversion-recovery BLADE magnetic resonance imaging of the brain: an alternative to spin-echo technique for detection of brain lesions in the unsedated pediatric patient?

RATIONALE AND OBJECTIVES: We compared contrast-enhanced T1-weighted magnetic resonance (MR) imaging of the brain using different types of data acquisition techniques: periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER, BLADE) imaging versus standard k-space sampling (conventional spin-echo pulse sequence) in the unsedated pediatric patient with focus on artifact reduction, overall image quality, and lesion detectability. MATERIALS AND METHODS: Forty-eight pediatric patients (aged 3 months to 18 years) were scanned with a clinical 1.5-T whole body MR scanner. Cross-sectional contrast-enhanced T1-weighted spin-echo sequence was compared to a T1-weighted dark-fluid fluid-attenuated inversion-recovery (FLAIR) BLADE sequence for qualitative and quantitative criteria (image artifacts, image quality, lesion detectability) by two experienced radiologists. Imaging protocols were matched for imaging parameters. Reader agreement was assessed using the exact Bowker test. RESULTS: BLADE images showed significantly less pulsation and motion artifacts than the standard T1-weighted spin-echo sequence scan. BLADE images showed statistically significant lower signal-to-noise ratio but higher contrast-to-noise ratios with superior gray-white matter contrast. All lesions were demonstrated on FLAIR BLADE imaging, and one false-positive lesion was visible in spin-echo sequence images. CONCLUSION: BLADE MR imaging at 1.5 T is applicable for central nervous system imaging of the unsedated pediatric patient, reduces motion and pulsation artifacts, and minimizes the need for sedation or general anesthesia without loss of relevant diagnostic information.     

Supraglottic carcinoma treated with curative radiation therapy: identification of prognostic groups with MR imaging

PURPOSE: To retrospectively assess the prognostic meaning of tumor characteristics depicted on pretreatment magnetic resonance (MR) images for local outcome in supraglottic squamous cell carcinoma treated with definitive radiation therapy. MATERIALS AND METHODS: Pretreatment MR images acquired in 84 patients with supraglottic carcinoma treated with curative radiation therapy were reviewed for tumor involvement of laryngeal sites including glottis, subglottis, pre-epiglottic space, laryngeal cartilages, and hypopharynx, and for extralaryngeal extension. The volume of each tumor was estimated, and mean tumor volume was calculated for the group of tumors in each T staging category. RESULTS: Results of univariate analysis showed MR imaging-determined primary tumor volume (P =.03), involvement of pre-epiglottic space (P =.008), abnormal signal intensity in thyroid cartilage (P =.04), and extralaryngeal extension beyond thyroid and/or cricoid cartilage (P =.02) to be significant predictors of local control rate. Results of multivariate analysis with the Cox regression model confirmed statistical significance for invasion of pre-epiglottic space (P =.004) and for abnormal signal intensities in thyroid cartilage adjacent to the anterior commissure (P =.04) and in cricoid cartilage (P =.01). Five-year local control rates were calculated from the regression coefficients of three independent MR imaging prognostic factors, and three prognostic groups were identified on the basis of these control rates. The 5-year local control rate in the high-risk group was 35%, significantly lower than the rates in the intermediate- and low-risk groups (60% and 89%, respectively; P =.002). CONCLUSION: MR imaging-determined pre-epiglottic space involvement and abnormal signal intensities in the thyroid cartilage adjacent to the anterior commissure and/or the cricoid cartilage are strong predictors of local outcome in supraglottic carcinoma treated with definitive radiation therapy.     

Serial isotropic three-dimensional fast FLAIR imaging: using image registration and subtraction to reveal active multiple sclerosis lesions

OBJECTIVE: Image registration and subtraction to detect the change of disease burden in multiple sclerosis on serial MR images should benefit from the use of high-resolution isotropic voxels. We compared 1.2-mm isotropic three-dimensional (3D) fast fluid-attenuated inversion recovery (FLAIR) images with standard 3-mm two-dimensional spin-echo images for the detection of new or enlarging lesions in longitudinal studies. SUBJECTS AND METHODS: Serial MR images were obtained at baseline, month 6 (n = 20), and month 7 (n = 16). For the half-yearly intervals, subtracted 3D FLAIR images and T2-weighted spin-echo images were compared. For the monthly intervals, subtracted 3D FLAIR images were compared with triple-dose contrast-enhanced T1-weighted spin-echo images. New, enlarging, and enhancing lesions were marked in consensus by two radiologists. RESULTS: At the half-yearly intervals, 3D FLAIR imaging detected more new or enlarging lesions than T2-weighted spin-echo imaging, both at the initial interpretation (80 vs 52; p < 0.001) and after a side-by-side comparison of the lesions (88 vs 65; p < 0.001). Post hoc analyses showed the largest benefit for new (rather than enlarging), for small, and for temporal lesions. At the monthly intervals, 32 enhancing lesions were detected on contrast-enhanced T1-weighted spin-echo images versus 20 new or enlarging lesions detected on 3D FLAIR images (p < 0.05). After a side-by-side comparison of the lesions, seven additional lesions were identified on 3D FLAIR images, making the difference with contrast-enhanced T1-weighted spin-echo images insignificant (27 vs 32; p > 0.05). CONCLUSION: Isotropic 3D FLAIR imaging holds great promise for the detection of new or enlarging lesions in multiple sclerosis using registration and subtraction techniques certainly at longer intervals.     

Dynamic contrast-enhanced T2*-weighted MR imaging of tumefactive demyelinating lesions.

PURPOSE: Dynamic contrast-enhanced T2*-weighted MR imaging has been helpful in characterizing intracranial mass lesions by providing information on vascularity. Tumefactive demyelinating lesions (TDLs) can mimic intracranial neoplasms on conventional MR images, can be difficult to diagnose, and often result in surgical biopsy for suspected tumor. The purpose of this study was to determine whether dynamic contrast-enhanced T2*-weighted MR imaging can be used to distinguish between TDLs and intracranial neoplasms that share common features on conventional MR images. METHODS: We retrospectively reviewed the conventional and dynamic contrast-enhanced T2*-weighted MR images and medical records of 10 patients with tumefactive demyelinating disease that was diagnosed by either biopsy or strong clinical suspicion supported by laboratory evaluation that included CSF analysis and evoked potential tests. Twelve TDLs in 10 patients and 11 brain tumors that appeared similar on conventional MR images were studied. Relative cerebral blood volume (rCBV) was calculated from dynamic MR data and was expressed as a ratio to contralateral normal white matter. rCBV values from 11 patients with intracranial neoplasms with very similar conventional MR imaging features were used for comparison. RESULTS: The rCBV values of TDLs ranged from 0.22 to 1.79 (n = 12), with a mean of 0.88 +/- 0.46 (SD). The rCBV values of intracranial neoplasms ranged from 1.55 to 19.20 (n = 11), with a mean of 6.47 +/- 6.52. The difference in rCBV values between the two groups was statistically significant (P =.009). The difference in rCBV values between TDLs and primary cerebral lymphomas (n = 4) was less pronounced but was statistically significant (P =.005). CONCLUSION: Dynamic contrast-enhanced T2*-weighted MR imaging is a useful diagnostic tool in differentiating TDLs from intracranial neoplasms and may therefore obviate unnecessary surgical biopsy.     

MRI with Gd-DTPA in tumours of larynx and hypopharynx

Twenty-eight patients with tumours of the larynx, divided into supraglottic, glottic, and subglottic lesions, and of the hypopharynx were examined by different MRI techniques using the paramagnetic contrast medium Gd-DTPA. The results of preoperative MRI were compared with clinical laryngoscopy and the pathological tumour classification. The examinations were carried out using plain T1-wand T2-weighted and Gd-DTPA enhanced T1-weighted sequences. Most studies included three slice orientations for optimal assessment of different tumour locations. The most accurate diagnostic information was given by Gd-DTPA-enhanced sequences. The combination of plain images, contrast-enhanced images and subtraction enabled precise assessment of deep infiltration. T2-weighted and proton density sequences conveyed more information about cartilage invasion and liquid-filled structures, but gave more artefacts than T1-weighted images. Laryngoscopy had advantages in T1-classified tumors, as the extent of the tumor could be seen, and offered histological information via biopsy. Diagnostic findings of MRI correlated in 85.7% with the pathologist's report, and laryngoscopy provided exact classification in only 64.3% of patients. Gd-DTPA-enhanced MRI is an important adjunct to non-contrast MR studies, and forms an ideal diagnostic supplement to laryngoscopy. Offprint requests to: T. Vogl     

Comparative study of fluorodeoxyglucose positron emission tomography and magnetic resonance imaging for the detection of spinal bone marrow infiltration in untreated patients with multiple myeloma

Background: The presence and extent of osteolytic bone lesions in untreated patients with multiple myeloma are important factors in the staging of the disease, and the extent of bone lesions in multiple myeloma cases significantly influences decisions regarding therapy. Recently, fluorodeoxyglucose positron emission tomography (FDG-PET) and magnetic resonance imaging (MRI) have been used to detect bone marrow involvement in patients with multiple myeloma.

Purpose: To compare the efficacy of FDG-PET and MRI for the detection of bone marrow infiltration into the spine in untreated patients with multiple myeloma.

Material and Methods: Twenty-two patients with multiple myeloma underwent both FDG-PET and spine MRI. The examined spinal regions by MRI included 21 thoracic and lumbar spines, one lumbar spine, and 12 cervical spines. The following imaging sequences were performed: T1-weighted spin-echo MRI with and without fat suppression, and T2-weighted spin-echo MRI in the sagittal plane. In the patients with bone marrow abnormalities, an additional contrast-enhanced T1-weighted spin-echo MR image and a fat-suppressed T1-weighted spin-echo MR image were obtained. Patients were divided into three groups on the basis of the criteria defined by Durie and Salmon: stage I (n=9), stage II (n=3), and stage III (n=10). The number and location of lesions detected in both FGD-PET and MRI were recorded, and the lesions were compared using the McNemar test. Bone marrow biopsy results, the patient's clinical examinations, and other imaging findings (MRI, FDG-PET, etc.) were used as references.

Results: In stages I and II (37 lesions in 12 patients), FDG-PET and MRI detected lesions in 78% (29 of 37 lesions) and 86% (32 of 37 lesions), respectively. However, the difference between the abilities of FDG-PET and MRI to detect lesions was not statistically significant (P=0.317). In stage III (101 lesions in 10 patients), FDG-PET and MRI detected lesions in 80% (81 of 101 lesions) and 92% (93 of 101 lesions), respectively. The difference between the abilities of FDG-PET and MRI to detect lesions was statistically significant (P=0.038).

Conclusion: MRI is superior to FDG-PET in detecting bone marrow involvement in the spine of patients with advanced multiple myeloma.