A qualitative approach to combined magnetic resonance imaging and spectroscopy in the diagnosis of prostate cancer

Purpose

To investigate the feasibility and diagnostic value of a whole prostate qualitative approach to combined magnetic resonance imaging and spectroscopy (MRI + MRS) in the detection of prostate cancer in patients with elevated PSA.

Materials and methods

Three hundred and fifty six subjects (mean serum PSA 11.47 ng/ml, range 0.40-133 ng/ml) were examined with fast-T2-weighted images (MRI) and 3D-magnetic resonance spectroscopy (MRS). Both modalities were qualitatively analyzed on a whole prostate basis by a single radiologist using a 4-point diagnostic scale. Prostate cancer was histopathologically proven in 220 patients and non-evidence of cancer was determined after at least 12 months clinical follow-up in 136 subjects.

Results

Receiver operating curve analysis revealed a significantly better diagnostic performance of MRI + MRS (A_z = 0.857) than MRI alone (A_z = 0.801) and MRS alone (A_z = 0.810). The sensitivity, specificity and accuracy of MRI + MRS for detection of prostate cancer were 72.3%, 92.6%, and 80.1%, respectively.

Conclusions

Spectral evaluation with a whole prostate qualitative approach is feasible in routine clinical practice. The combination of MRI and MRS yields superior diagnostic results than either modality alone.     

Use of foetal MRI in diagnosing hepatic hemangioendotheliomas: A report of four cases

Objective

To examine the appearance of foetal hepatic hemangioendotheliomas using prenatal magnetic resonance imaging (MRI) and to conclude whether MRI provides additional information to that obtained with ultrasonography (US).

Materials and methods

Four foetuses with hepatic hemangioendotheliomas were evaluated by US and MRI between 2005 and 2008. MRI was performed on four foetuses at 33 + 4, 37 + 4, 24 and 21 + 6 weeks gestation following US evaluations that demonstrated foetal abdominal tumours. The prenatal US and MRI findings were compared with the postnatal physical examination, enhancement computed tomography (CT) and serial ultrasound examinations, or with the pathology exams, retrospectively.

Results

All four foetuses showed very similar prenatal MRI findings. In each case, the foetal MRI detected an isolated vascular hepatic tumour with low T1 and inhomogeneous high T2 signal intensity. In one case, multiple scalp hemangiomas were detected in the postnatal physical examination, but not with the prenatal US and MRI exams. In the other three cases, the prenatal US and MRI findings were in complete agreement with the postnatal diagnoses.

Conclusion

Prenatal MRI is effective in the assessment of foetal hepatic hemangioendotheliomas. Prenatal MRI may provide a useful adjunct to US in assessing foetal hepatic tumours.     

1H-MRSI of prostate cancer: The relationship between metabolite ratio and tumor proliferation

Purpose

To investigate whether 1H-MRSI can be used to predict the proliferative activity of prostate cancer.

Materials and methods

Thirty-eight patients with prostate cancer (PCa) and thirty-three patients with benign prostate hyperplasia (BPH) were included in this study. Patients were examined in supine position using a 1.5 T superconducting magnetic scanner equipped with a pelvic phased-array multi-coil and CSI-3D-PROSTATE sequence. Commercial software was used to acquire and process MR spectroscopic imaging data. Mean (Cho + Cr)/Cit ratios of PCa, BPH, and peripheral zone (PZ) were calculated. Cellularity of PCa was recorded based on hematoxylin and eosin staining. PCNA was detected using immunohistochemical techniques.

Results

The mean (Cho + Cr)/Cit ratio of the peripheral zone (0.38 ± 0.09) was lower than that of BPH (0.51 ± 0.19) (P < 0.05). The average value of (Cho + Cr)/Cit ratio of prostate cancer was 3.98 ± 0.12. The (Cho + Cr)/Cit ratio of prostate cancer was higher than that of the peripheral zone and BPH (P < 0.05). The cellularity and PCNA LI of prostate cancer were 12.90 ± 4.07% and 72.1 ± 19.01%, respectively. The (Cho + Cr)/Cit ratio of prostate cancer positively correlated with tumor cellularity (r = 0.582, P = 0.027) and PCNA LI (r = 0.495, P = 0.022).

Conclusion

The (Cho + Cr)/Cit ratio of PCa can reveal the differences in proliferative activity between PCa and BPH. MRSIs are therefore able to predict the proliferative rate of variously differentiated prostate cancers.     

CT and MR imaging characteristics of infantile hepatic hemangioendothelioma

Aim

This study aims to analyze computed tomography (CT) and magnetic resonance (MR) imaging features of infantile hepatic hemangioendotheliomas before and after treatment.

Materials and methods

CT and MR examinations of seven infants with biopsy proven hepatic hemangioendotheliomas were retrospectively analyzed. The distribution, number, size, imaging appearance, enhancement pattern and post-treatment changes of the tumors were evaluated.

Results

A total of 153 hepatic hemangioendotheliomas were detected on CT (111) and MR (42) imaging. In six infants, 109/111 (98.2%) tumors were hypodense and 2/111 (1.8%) lesions contained calcification on unenhanced CT. On MR imaging, all 42 lesions in one infant were heterogeneously T1-hypointense and T2-hyperintense compared to the normal liver parenchyma. Contrast-enhanced CT and MRI showed peripheral rim (51.6%), uniform (48.4%), fibrillary (33.3%), and nodular (28.8%) contrast enhancement in the hepatic arterial phase. Homogeneous (100%), rim (98.2%) and mixed enhancement patterns were noted in tumors <1.0 cm, >2.0 cm and 1.0-2.0 cm in diameter respectively in the hepatic arterial phase. In three patients who underwent steroid therapy, follow-up CT examination demonstrated tumor size reduction and increased intra-tumoral calcification in two patients.

Conclusion

Infantile hepatic hemangioendotheliomas show some typical imaging features and size-dependent pattern of contrast enhancement on CT and MR imaging, which allow accurate imaging diagnosis and post-treatment evaluation.     

Hepatic caudate vein in Budd-Chiari syndrome: Depiction by using magnetic resonance imaging

Objective

To study the visibility of the caudate vein and its diameter on MR imaging in healthy people and in patients with Budd-Chiari syndrome.

Materials and methods

In this study there were 14 patients with Budd-Chiari syndrome and 54 healthy subjects without hepatic lesion or liver disease, all of whom had upper abdominal enhanced MRI. The visibility of the caudate vein and its diameter on MR images was compared between Budd-Chiari patients and healthy subjects, and among Budd-Chiari patients, the correlation between the visibility of caudate vein and extrahepatic collaterals were compared.

Results

Caudate vein was noted in 64% of patients with Budd-Chiari syndrome and in 7% of healthy subjects (P = 0.000). The diameter of the caudate vein visualized on MR imaging in Budd-Chiari syndrome was significantly larger than that in healthy group (7.3 ± 3.9 mm vs 2.6 ± 0.6 mm, P = 0.037). Among Budd-Chiari patients, both caudate vein and extrahepatic collateral veins were noted in 9 patients, only extrahepatic collateral veins were noted in 4 patients and neither caudate vein nor extrahepatic collateral veins were noted in 1 patient. No correlation was found between the visibility of caudate vein and that of extrahepatic collateral vein in patients with Budd-Chiari (P = 0.375).

Conclusion

Gadolinium enhanced dynamic MR imaging can visualize hepatic caudate vein frequently. The visibility and dilation of hepatic caudate veins on MR imaging in Budd-Chiari syndrome were more frequent than in control subjects. MR depiction of a caudate vein may help differentiate Budd-Chiari from cirrhosis.     

Proton MR spectroscopy in patients with pyogenic brain abscess: MR spectroscopic imaging versus single-voxel spectroscopy

Purpose

Single-voxel spectroscopy (SVS) has been the gold standard technique to diagnose the pyogenic abssess. Two-dimensional magnetic resonance spectroscopic imaging (MRSI) is able to provide spatial distribution of metabolic concentration, and is potentially more suitable for differential diagnosis between abscess and necrotic tumors. Therefore, the purpose of this study was to evaluate the equivalence of MRSI and SVS in the detection of the metabolites in pyogenic brain abscesses.

Materials and methods

Forty-two patients with pyogenic abscesses were studied by using both SVS and MRSI methods. Two neuroradiologists reviewed the MRS data independently. A κ value was calculated to express inter-reader agreement of the abscesses metabolites, and a correlation coefficient was calculated to show the similarity of two spectra. After consensus judgment of two readers, the binary value of metabolites of pyogenic abscesses (presence or absence) was compared between SVS and MRSI.

Results

The consistency of spectral interpretation of the two readers was very good (κ ranged from 0.95 to 1), and the similarity of two spectra was also very high (cc = 0.9 ± 0.05). After consensus judgment of two readers, the sensitivities of MRSI ranged from 91% (acetate) to 100% (amino acids, succinate, lactate, lipid), and the specificities of MRSI were 100% for detecting all metabolites with SVS as reference.

Conclusion

SVS and MRSI provide similar metabolites in the cavity of pyogenic brain abscess. With additional metabolic information of cavity wall and contralateral normal-appearing brain tissue, MRSI would be a more suitable technique to differentiate abscesses from necrotic tumors.     

MR-perfusion (MRP) and diffusion-weighted imaging (DWI) in prostate cancer: Quantitative and model-based gadobenate dimeglumine MRP parameters in detection of prostate cancer

Background

Various MR methods, including MR-spectroscopy (MRS), dynamic, contrast-enhanced MRI (DCE-MRI), and diffusion-weighted imaging (DWI) have been applied to improve test quality of standard MRI of the prostate.

Purpose

To determine if quantitative, model-based MR-perfusion (MRP) with gadobenate dimeglumine (Gd-BOPTA) discriminates between prostate cancer, benign tissue, and transitional zone (TZ) tissue.

Material and methods

27 patients (age, 65 ± 4 years; PSA 11.0 ± 6.1 ng/ml) with clinical suspicion of prostate cancer underwent standard MRI, 3D MR-spectroscopy (MRS), and MRP with Gd-BOPTA. Based on results of combined MRI/MRS and subsequent guided prostate biopsy alone (17/27), biopsy and radical prostatectomy (9/27), or sufficient negative follow-up (7/27), maps of model-free, deconvolution-based mean transit time (dMTT) were generated for 29 benign regions (bROIs), 14 cancer regions (cROIs), and 18 regions of transitional zone (tzROIs). Applying a 2-compartment exchange model, quantitative perfusion analysis was performed including as parameters: plasma flow (PF), plasma volume (PV), plasma mean transit time (PMTT), extraction flow (EFL), extraction fraction (EFR), interstitial volume (IV) and interstitial mean transit time (IMTT). Two-sided T-tests (significance level p < 0.05) discriminated bROIs vs. cROIs and cROIs vs. tzROIs, respectively.

Results

PMTT discriminated best between bROIs (11.8 ± 3.0 s) and cROIs (24.3 ± 9.6 s) (p < 0.0001), while PF, PV, PS, EFR, IV, IMTT also differed significantly (p 0.00002-0.0136). Discrimination between cROIs and tzROIs was insignificant for all parameters except PV (14.3 ± 2.5 ml vs. 17.6 ± 2.6 ml, p < 0.05).

Conclusions

Besides MRI, MRS and DWI quantitative, 2-compartment MRP with Gd-BOPTA discriminates between prostate cancer and benign tissue with several parameters. However, distinction of prostate cancer and TZ does not appear to be reliable.     

CT features of adenomyosis

Objectives

To determine the computed tomography (CT) features of adenomyosis in patients with known adenomyosis as established with magnetic resonance (MR) imaging.

Methods

A computerized search identified 16 women with pelvic MR diagnosis of adenomyosis who also had enhanced pelvic CT. Original CT reports were reviewed for potential prospective diagnosis of adenomyosis. CT images were reviewed for enhancement phase, inner and outer myometrium attenuation, uterine enlargement (width>6 cm), inner myometrial thickening (≥12 mm), and myometrial cysts.

Results

Adenomyosis was detectable on CT in 8 of 16 patients. For these 8 patients, inner and outer myometrium distinction was excellent in 7 (88%) and limited in 1 (12%), and mean inner myometrial thickness was 25 mm (range 14-47 mm). CT enhancement phase was parenchymal in 7 (88%), uterus was enlarged in 8 (100%), and 7 (88%) had myometrial cysts. Adenomyosis was focal in 5 (63%), diffuse in 2 (25%), and both in 1 (12%). None of the original CT reports included adenomyosis as a diagnosis.

Conclusions

CT can suggest a diagnosis of adenomyosis based on uterine enlargement, thickened inner myometrium, and/or myometrial cysts.     

MR image analysis: Longitudinal cardiac motion influences left ventricular measurements

Background

Software for the analysis of left ventricular (LV) volumes and mass using border detection in short-axis images only, is hampered by through-plane cardiac motion. Therefore we aimed to evaluate software that involves longitudinal cardiac motion.

Methods

Twenty-three consecutive patients underwent 1.5-Tesla cine magnetic resonance (MR) imaging of the entire heart in the long-axis and short-axis orientation with breath-hold steady-state free precession imaging. Offline analysis was performed using software that uses short-axis images (Medis MASS) and software that includes two-chamber and four-chamber images to involve longitudinal LV expansion and shortening (CAAS-MRV). Intraobserver and interobserver reproducibility was assessed by using Bland-Altman analysis.

Results

Compared with MASS software, CAAS-MRV resulted in significantly smaller end-diastolic (156 ± 48 ml versus 167 ± 52 ml, p = 0.001) and end-systolic LV volumes (79 ± 48 ml versus 94 ± 52 ml, p < 0.001). In addition, CAAS-MRV resulted in higher LV ejection fraction (52 ± 14% versus 46 ± 13%, p < 0.001) and calculated LV mass (154 ± 52 g versus 142 ± 52 g, p = 0.004). Intraobserver and interobserver limits of agreement were similar for both methods.

Conclusion

MR analysis of LV volumes and mass involving long-axis LV motion is a highly reproducible method, resulting in smaller LV volumes, higher ejection fraction and calculated LV mass.     

Oculomotor paralysis: 3D-CISS MR imaging with MPR in the evaluation of neuralgic manifestation and the adjacent structures

Purpose

To evaluate the value of three-dimensional (3D) constructive interference in steady-state (CISS) magnetic resonance (MR) imaging with multi-planar reconstruction (MPR) in displaying the relationship between the oculomotor nerve and its adjacent structures for patients with oculomotor paralysis.

Materials and methods

17 consecutive patients with oculomotor paralysis were examined with 3D-CISS and conventional spin-echo (SE) sequences on a 1.5-Tesla MR system. Original transverse and MPR images were used for image interpretation. The features of the oculomotor nerve and its adjacent structures were identified. The diagnosis was surgically confirmed in all patients.

Results

Through 3D-CISS with MPR images, obvious relationship of the oculomotor nerve and its adjacent structures was demonstrated on 17 patients. Of those oculomotor nerves, 15 were compressed by the arteries (n = 15), one by the craniopharyngioma (n = 1), and another one by the neurofibroma (n = 1).

Conclusion

3D-CISS MR imaging with MPR provides an excellent way to characterize the relationship between the nerve and its adjacent structures in the cisternal segment of the oculomotor nerve in the patients with oculomotor paralysis. Moreover, this method shows anatomical details for imaging diagnosis and surgical procedure.     

High resolution T2 weighted liver MR imaging using functional residual capacity breath-hold with a 1.0-Tesla scanner

Purpose

During acquisition of rapid high resolution (HR) T2 weighted (T2W) liver magnetic resonance (MR) images using a 1.0-Tesla (T) scanner, the liver is segmented into odd and even sections that are acquired at two different times using the multi-breath-hold (MBH) strategy. Misalignment between the two breath-hold (B-H) images may result in the occurrence of a blind area and a decrease in diagnostic accuracy. Here, a functional residual capacity (FRC) B-H method was developed to overcome this problem.

Material and methods

Twenty-five volunteers were enrolled. The sagittal images were reconstructed from whole liver transverse images. When the B-H phases are different, misalignment may occur in the craniocaudal and anterior-posterior (AP) directions. In this study, misalignments of the abdominal wall were measured in the AP direction. The misalignment was compared between four B-H phases, maximum inspiration (MI), maximum expiration (ME), voluntary expiration (VE) and FRC using one-way repeated measures ANOVA. Differences between groups were compared using the t-test for multi-group comparisons. In addition, qualitative analysis of misalignment was performed between VE and FRC in 52 clinical patients and the χ² test was performed.

Results

The misalignment widths of FRC, ME, MI and VE B-Hs were 2.7 ± 3.8, 6.4 ± 7.4, 9.1 ± 8.4 and 6.0 ± 6.7 mm, respectively. Misalignment of the liver position using FRC was significantly smaller than for the other B-H methods (p < 0.05). Significant differences between the VE B-H and FRC B-H were also observed in the qualitative analysis (p < 0.05).

Conclusion

The liver positions obtained when using FRC B-H were significantly more reproducible than when using the other B-H methods. The FRC B-H method resulted in a reduction in the blind area and an extension of the diagnostic area to the whole liver.     

A semi-automated method for non-invasive internal organ weight estimation by post-mortem magnetic resonance imaging in fetuses, newborns and children

Magnetic resonance (MR) imaging allows minimally invasive autopsy, especially when consent is declined for traditional autopsy. Estimation of individual visceral organ weights is an important component of traditional autopsy.

Objective

To examine whether a semi-automated can be used for non-invasive internal organ weight measurement using post-mortem MR imaging in fetuses, newborns and children.

Methods

Phase 1: In vitro scanning of 36 animal organs (heart, liver, kidneys) was performed to check the accuracy of volume reconstruction methodology. Real volumes were measured by water displacement method. Phase 2: Sixty-five whole body post-mortem MR scans were performed in fetuses (n = 30), newborns (n = 5) and children (n = 30) at 1.5 T using a 3D TSE T2-weighted sequence. These data were analysed offline using the image processing software Mimics 11.0.

Results

Phase 1: Mean difference (S.D.) between estimated and actual volumes were −0.3 (1.5) ml for kidney, −0.7 (1.3) ml for heart, −1.7 (3.6) ml for liver in animal experiments. Phase 2: In fetuses, newborns and children mean differences between estimated and actual weights (S.D.) were −0.6 (4.9) g for liver, −5.1 (1.2) g for spleen, −0.3 (0.6) g for adrenals, 0.4 (1.6) g for thymus, 0.9 (2.5) g for heart, −0.7 (2.4) g for kidneys and 2.7 (14) g for lungs. Excellent co-correlation was noted for estimated and actual weights (r² = 0.99, p < 0.001). Accuracy was lower when fetuses were less than 20 weeks or less than 300 g.

Conclusion

Rapid, accurate and reproducible estimation of solid internal organ weights is feasible using the semi-automated 3D volume reconstruction method.     

State-of-the-art radiological techniques improve the assessment of postoperative lung function in patients with non-small cell lung cancer

Purpose

The purpose of this study was to compare predictive capabilities for postoperative lung function in non-small cell lung cancer (NSCLC) patients of the state-of-the-art radiological methods including perfusion MRI, quantitative CT and SPECT/CT with that of anatomical method (i.e. qualitative CT) and traditional nuclear medicine methods such as planar imaging and SPECT.

Materials and methods

Perfusion MRI, CT, nuclear medicine study and measurements of %FEV₁ before and after lung resection were performed for 229 NSCLC patients (125 men and 104 women). For perfusion MRI, postoperative %FEV₁ (po%FEV₁) was predicted from semi-quantitatively assessed blood volumes within total and resected lungs, for quantitative CT, it was predicted from the functional lung volumes within total and resected lungs, for qualitative CT, from the number of segments of total and resected lungs, and for nuclear medicine studies, from uptakes within total and resected lungs. All SPECTs were automatically co-registered with CTs for preparation of SPECT/CTs. Predicted po%FEV₁s were then correlated with actual po%FEV₁s, which were measured %FEV₁s after operation. The limits of agreement were also evaluated.

Results

All predicted po%FEV₁s showed good correlation with actual po%FEV₁s (0.83 ≤ r ≤ 0.88, p < 0.0001). Perfusion MRI, quantitative CT and SPECT/CT demonstrated better correlation than other methods. The limits of agreement of perfusion MRI (4.4 ± 14.2%), quantitative CT (4.7 ± 14.2%) and SPECT/CT (5.1 ± 14.7%) were less than those of qualitative CT (6.0 ± 17.4%), planar imaging (5.8 ± 18.2%), and SPECT (5.5 ± 16.8%).

Conclusions

State-of-the-art radiological methods can predict postoperative lung function in NSCLC patients more accurately than traditional methods.     

Ileal Crohn's disease: MRI with endoscopic correlation

Purpose

To evaluate activity staging of Crohn's disease (CD) measured with MR-enterography using ileoscopy as reference standard.

Materials and methods

A prospective study was made of 61 patients with CD. All patients underwent MR-enterography and ileoscopy. MRI activity was measured by means of an ad hoc developed score, as well as by analysis of the imaging findings, and was compared with the SES-CD score obtained via ileoscopy. Examinations were performed using a 1.0 T scanner.

Results

MRI score discriminates between active and inactive disease with an area under the ROC curve of 0.941. Overall correlation with the standard reference SES-CD score was moderate to strong (Spearman's r = 0.62 p < 0.001).Agreement between both methods in staging patients with ileal CD as inactive, mild or moderate to severe was good (Cohen's κ = 0.60). Differences in means of the MRI activity scores of the three groups showed statistical significance (p < 0.01).

Conclusions

The MRI score is a reliable predictor of activity in ileal CD and can stage patients in a way comparable to endoscopy. 1.0 T scans are valid for performing radiological evaluation of ileal Crohn's disease.     

Magnetic resonance imaging in fetal anomalies: What does it add to 3D and 4D US?

Objective

The objective of our study is to evaluate the contribution of adding MRI findings to sonographic data when assessing fetal anomalies and to determine how this addition may affect the management of pregnancy.

Study design

We prospectively examined 26 fetuses who had sonographically suspected congenital anomalies over a period of 1 year. 2D/3D and 4D ultrasound, Doppler and magnetic resonant imaging was done for all patients. MRI was done within 1 week following US examination. The maternal age range was 18-39 years. The gestational age range was 15-38 weeks (mean age = 29 weeks). Ultrasound and magnetic resonance findings were compared together.

Results

We reported different types of congenital anomalies including eight cases of isolated central nervous system anomalies, four abdominal, five musculoskeletal anomalies, seven cases of renal anomalies and two cases of Meckel Gruber syndrome. MRI and sonography showed concordant findings in 18 cases. MRI changed the diagnosis in five cases and provided additional information in three cases. Ultrasound was superior to magnetic resonance imaging in three cases.

Conclusion

Our results showed that fetal MR imaging can be used as a complementary modality to US in diagnosing fetal abnormality in which US findings are inconclusive or equivocal.     

Persistent bone marrow edema after osteochondral autograft transplantation in the knee joint

Background and objective

The assessment of bone marrow edema-like signal intensity in magnetic resonance imaging (MRI) in patients after osteochondral autograft transplantation (OCT) in the knee joint is a parameter of yet indefinite value. This study determines the prevalence of persistent edema-like signal intensity in OCT patients and evaluates the correlation between edema and morphological imaging findings of the graft and clinical pain symptoms.

Materials and methods

In this longitudinal observational study, 10 patients after OCT were followed by MRI prospectively 1 month, 3 months, 6 months, 12 months, and 24 months post-operatively. All MR examinations were performed on a 1.0 T MR unit with the same protocol using a modified scoring system (magnetic resonance observation of cartilage repair tissue—MOCART) for evaluation. Edema-like signal intensity in and beneath the osteochondral graft was assessed in its prevalence and graded using a coronal short tau inversion recovery fast spin echo (STIR-FSE) sequence: grade 1, normal; grade 2, moderate (diameter <2 cm); grade 3, severe (diameter >2 cm). The finding of edema-like signal intensity was correlated with graded parameters describing the morphology of the repair tissue assessed in a sagittal dual FSE sequence including: (a) surface of repair tissue: grade 1, intact; grade 2, damaged. (b) Cartilage interface: grade 1, complete; grade 2, incomplete. (c) Bone interface: grade 1, complete; grade 2, delamination. The finding of edema-like signal intensity was also correlated with the KOOS pain score assessing knee pain after 12 months.

Results

Initially, after 1 month the prevalence of edema-like signal intensity was 70% (7/10 patients) and finally after 24 months 60% (6/10 patients). We found no significant relationship between the prevalence and degree of edema-like signal intensity and parameters describing the morphology of the repair tissue. Also the clinical pain score did not show significant correlation with edema.

Conclusion

Persistent bone marrow edema-like signal intensity in MRI is frequently found in patients after OCT and may post-operatively continue for years without significant relation to delamination and loss of the graft and knee pain.     

Quantitative diffusion tensor deterministic and probabilistic fiber tractography in relapsing-remitting multiple sclerosis

Purpose

Our aim was to study the quantitative fiber tractography variations and patterns in patients with relapsing-remitting multiple sclerosis (RRMS) and to assess the correlation between quantitative fiber tractography and Expanded Disability Status Scale (EDSS).

Material and methods

Twenty-eight patients with RRMS and 28 age-matched healthy volunteers underwent a diffusion tensor MR imaging study. Quantitative deterministic and probabilistic fiber tractography were generated in all subjects. And mean numbers of tracked lines and fiber density were counted. Paired-samples t tests were used to compare tracked lines and fiber density in RRMS patients with those in controls. Bivariate linear regression model was used to determine the relationship between quantitative fiber tractography and EDSS in RRMS.

Results

Both deterministic and probabilistic tractography's tracked lines and fiber density in RRMS patients were less than those in controls (P < .001). Both deterministic and probabilistic tractography's tracked lines and fiber density were found negative correlations with EDSS in RRMS (P < .001). The fiber tract disruptions and reductions in RRMS were directly visualized on fiber tractography.

Conclusion

Changes of white matter tracts can be detected by quantitative diffusion tensor fiber tractography, and correlate with clinical impairment in RRMS.     

Evaluation of CT and MRI scanning among cancer patients in Ontario

Background

Computed tomography (CT) and magnetic resonance imaging (MRI) utilization in Ontario increased drastically since the early 1990s. The effect of an increased number of cancer diagnoses, and an increase in indications for scans has not been assessed. This study was conducted to determine trends in utilization of CT and MRI in cancer patients in Ontario over a period of 9 years.

Methods

Using Ontario Health Insurance Plan billing data linked to the Ontario Cancer Registry, rates of CT and MRI were analyzed by region, year, scan type and socioeconomic status.

Results

CT in cancer patients increased 2.3-fold and accounted for approximately 24% of these scans. MRI in cancer patients increased by 4.2-fold and accounted for approximately 10% of these scans. Imaging rates for cancer patients increased more gradually than that of the general population. Substantial variation in the rate of both scans by region of patient residence existed. Even greater variation by the location of the scanner was demonstrated, indicating that many cancer patients traveled outside their region for imaging. There was little evidence of variation in scanning rates by socioeconomic status.

Conclusion

A minority of CT and MRI performed in Ontario are for cancer care. Regional variation in imaging rates suggest that utilization guidelines be developed or knowledge transfer initiatives improve compliance to existing guidelines are needed. A significant number of cancer patients travel outside their region for diagnostic imaging; this should influence decisions about the location of new scanners.     

Whole-body MRI for primary evaluation of malignant disease in children

Objective

The aim of this study was to compare diagnostic accuracy of whole-body (WB) MRI to a combined reference standard of conventional cross-sectional imaging methods and FDG-PET in the detection of malignant disease spread in children.

Materials and methods

24 children (age between 5 and 18 years) with malignant diseases (mainly Hodgkin's lymphoma and different types of sarcoma) initially examined with conventional cross-sectional imaging methods (ultrasound, computed tomography, or magnetic resonance imaging) were examined prospectively with whole-body MRI (1.5 T) and FDG-PET. Studies were read by two nuclear medicine physicians (FDG-PET) and two radiologists (WB-MRI) independently in a blinded manner and each study type was evaluated in consensus. The reference standard was defined as pathological lesions detected in the same location both in FDG-PET and another conventional cross-sectional imaging method.

Results

Overall 190 lesions were detected by WB-MRI and 155 lesion were found by FDG-PET. 106 lesions fulfilled the criteria of the reference standard (42 osseous and 64 extraosseous lesions) from which 102 were detected by WB-MRI (sensitivity of 96%). All bone lesions were detected and extra-skeletal lesions were identified with a sensitivity of 93.8%. Overall 88 lesions detected by WB-MRI were not part of the reference standard from which 33 were lesions of the peripheral skeleton not imaged by conventional cross-sectional imaging studies. 4 lesions of the reference standard were not identified by WB-MRI which were all lymph nodes.

Conclusion

WB-MRI is a radiation free imaging technique with high sensitivity for the detection of malignant disease spread in particular beneficial for children. In patients with suspected bone lesions it should be considered for initial disease evaluation prior to specific and regional imaging methods to reduce the overall number of imaging examinations and radiation exposure.     

Planimetry of the aortic valve orifice area: Comparison of multislice spiral computed tomography and magnetic resonance imaging

Objective

We sought to determine the comparability of multislice computed tomography (MSCT) and magnetic resonance imaging (MRI) for measuring the aortic valve orifice area (AVA) and grading aortic valve stenosis.

Materials and methods

Twenty-seven individuals, among them 18 patients with valvular stenosis, underwent AVA planimetry by both MSCT and MRI. In the subset of patients with valvular stenosis, AVA was also calculated from transthoracic Doppler echocardiography (TTE) using the continuity equation.

Results

There was excellent correlation between MSCT and MRI (r = 0.99) and limits of agreement were in an acceptable range (±0.42 cm²) although MSCT yielded a slightly smaller mean AVA than MRI (1.57 ± 0.83 cm² vs. 1.67 ± 0.98 cm², p < 0.05). However, in the subset of patients with valvular stenosis, the mean AVA was not different between MSCT and MRI (1.05 ± 0.30 cm² vs. 1.04 ± 0.39 cm²; p > 0.05). The mean AVAs on both MSCT and MRI were systematically larger than on TTE (0.88 ± 0.28 cm², p < 0.001 each). Using an AVA of 1.0 cm² on TTE as reference, the best threshold for detecting severe-to-critical stenosis on MSCT and MRI was an AVA of 1.25 cm² and 1.30 cm², respectively, resulting in an accuracy of 96% each.

Conclusion

Our study specifies recent reports on the suitability of MSCT for quantifying AVA. The data presented here suggest that certain methodical discrepancies of AVA measurements exist between MSCT, MRI and TTE. However, MSCT and MRI have shown excellent correlation in AVA planimetry and similar accuracy in grading aortic valve stenosis.