Imaging findings in phyllodes tumors of the breast

Purpose

To study the radiological appearance and pathological features of breast phyllodes tumors (PTs), and to enhance the recognition of the tumor.

Materials and methods

Clinical and imaging findings were retrospectively reviewed in 24 women with PTs confirmed by surgical pathology. All of the 24 patients had preoperative MRI and sonography, and 10 had preoperative mammography.

Results

The histologic findings were benign, borderline and malignant PTs in 16.7% (4/24), 45.8% (11/24) and 37.5% (9/24) of cases, respectively. The tumor size (p = 0.001), irregular shape on sonographic imaging (p = 0.039), internal non-enhanced septations (p = 0.009), silt-like changes in enhanced images (p = 0.006) and signal changes from T2-weighted to enhanced images on MRI (p = 0.001) correlated significantly with the histologic grade; the BI-RADS category of the MRI could reflect the PT's histologic grade with a correlation coefficient of 0.440 (p = 0.031). If the category BI-RADS ≥4a was considered to be a suspicious malignant lesion, the diagnostic accuracy of mammography, US and MRI would be 70% (7/10), 62.5% (15/24) and 95.8% (23/24), respectively.

Conclusion

The tumor size and several US and MRI findings can be used to help preoperatively determine the histologic grade of breast PTs. When a patient presents with a progressively enlarging, painless breast mass, MRI should be recommended first.     

Sandwich sign of Borrmann type 4 gastric cancer on diffusion-weighted magnetic resonance imaging

Objective

To assess the appearance of Borrmann type 4 (BT-4) gastric cancer on diffusion-weighted magnetic resonance imaging (DWI) and to investigate the potential of qualitative and quantitative DW images analysis to differentiate BT-4 gastric cancer from poorly distended normal stomach wall.

Materials and methods

DWI was performed on 23 patients with BT-4 gastric cancer and 23 healthy volunteers. The signal characteristics and correlated histopathological basis of the cancers on DWI were investigated. The contrast-to-noise ratios (CNR) of cancer were compared between DWI and T1WI/T2WI_. The thickness and apparent diffusion coefficient (ADC) of cancer and normal stomach wall were compared.

Results

All of the gastric cancers displayed hyperintensity compared to the nearby normal gastric wall on DWI. A three-layer sandwich sign that demonstrated high signal intensity in the inner and outer layer, and low signal intensity in the intermediate layer was observed in 69.6% of cancers on DWI. The low signal intensity represents the muscularis propria through the comparison with pathology, and it is postulated that scattering distribution of the cancer cells in this layer causes less damage and subsequently less restriction of water movement, which causes the low signal intensity on DWI. The CNR obtained with DWI was higher than that with T1WI and T2WI (P < 0.001). The mean ADC value of BT-4 gastric cancer was significantly lower than the poorly distended normal stomach wall (1.12 ± 0.23 × 10⁻³ mm²/s vs. 1.93 ± 0.22 × 10⁻³ mm²/s, P < 0.01).

Conclusion

DWI can highlight the signals of BT-4 gastric cancer which may present a characteristic three-layer sandwich sign, and ADC values are helpful in the discrimination of gastric cancer from poorly distended stomach wall.     

Performance of unenhanced respiratory-gated 3D SSFP MRA to depict hepatic and visceral artery anatomy and variants

Objectives

To prospectively evaluate the performance of unenhanced respiratory-gated magnetization-prepared 3D-SSFP inversion recovery MRA (unenhanced-MRA) to depict hepatic and visceral artery anatomy and variants in comparison to contrast-enhanced dynamic gradient-echo MRI (CE-MRI) and to digital subtraction angiography (DSA).

Methods

Eighty-four patients (55.6 ± 12.4 years) were imaged with CE-MRI (TR/TE 3.5/1.7 ms, TI 1.7 ms, flip-angle 15°) and unenhanced-MRA (TR/TE 4.4/2.2 ms, TI 200 ms, flip-angle 90°). Two independent readers assessed image quality of hepatic and visceral arteries on a 4-point-scale. Vessel contrast was measured by a third reader. In 28 patients arterial anatomy was compared to DSA.

Results

Interobserver agreement regarding image quality was good for CE-MRI (κ = 0.77) and excellent for unenhanced-MRA (κ = 0.83). Unenhanced-MRA yielded diagnostic image quality in 71.6% of all vessels, whereas CE-MRI provided diagnostic image quality in 90.6% (p < 0.001). Vessel-based image quality was significantly superior for all vessels at CE-MRI compared to unenhanced-MRA (p < 0.01). Vessel contrast was similar among both sequences (p = 0.15). Compared to DSA, CE-MRI and unenhanced-MRA yielded equal accuracy of 92.9–96.4% for depiction of hepatic and visceral artery variants (p = 0.93).

Conclusions

Unenhanced-MRA provides diagnostic image quality in 72% of hepatic and visceral arteries with no significant difference in vessel contrast and similar accuracy to CE-MRI for depiction of hepatic and visceral anatomy.     

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

Objective

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

Materials and methods

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

Results

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

Conclusion

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

Neurochemical-structural changes evaluation of brain in patients with obstructive sleep apnea syndrome

Purpose

To evaluate neurochemical and structural changes in the patients with newly diagnosed obstructive sleep apnea syndrome (OSAS) by MR spectroscopy (MRS), T2 relaxometry, and diffusion weighted imaging (DWI).

Material and methods

Following the acquisition of routine cranial MR, MRS, T2 relaxometry, and DWI images; spectroscopic metabolite ratios and DWI–T2 relaxometry findings of the thalami, hippocampi, frontal white matter (FWM) and frontal cortex of 24 OSAS patients and 9 controls were statistically compared. The relationship between two groups was evaluated with Mann–Whitney test.

Results

Spectroscopic measurements in the frontal cortex and frontal white matter of the OSAS patients revealed significantly lower NAA/Cr ratios than those of the control group (P = 0.004 and P = 0.006, respectively). The measurements in the frontal white matter of the OSAS patients exhibited significantly lower NAA/Cho ratios compared with those of the control group (P = 0.005). Thalamic Cho/Cr ratios of the patient group were significantly higher than those of the control group (P = 0.002). In terms of the ADC–T2 relaxometry values, there was no significant relationship between the patient and the control groups (P > 0.05).

Conclusion

MRS is a useful and non-invasive modality in showing neurochemical changes in various regions of the brain but our data does not show any change on diffusion weighting or T2 quantification in the OSAS group. DWI and T2 relaxometry appear to be not effective techniques to evaluate the brain structural changes of the patients with newly diagnosed OSAS.     

An experimental study on acute brain radiation injury: Dynamic changes in proton magnetic resonance spectroscopy and the correlation with histopathology

Purpose

To investigate the correlation between the alterations of single-voxel ¹H MRS and the histopathological characteristics of radiation brain injury following radiation.

Materials and methods

Twenty-seven rabbits were randomized into nine groups to receive radiation with a single dose of 25 Gy. The observation time points included a pre-radiation and 1, 2, 3, 4, 5, 6, 7, and 8 wk following radiation. Each treatment group underwent conventional MRI and single-voxel ¹H MRS, N-acetyl aspartate (NAA), choline (Cho), and creatine (Cr) were observed over the region of interest, and the presence or absence of lactate (Lac) and lipid (Lip) was detected. Histological specimens of each group were obtained after image acquisition.

Results

The values of Cho were significantly increased in the first 3 wk, and decreased over the following 5 wk after radiation. Levels of NAA showed a trend toward a decrease 5 wk after radiation. The levels of Cr were not changed between before and after radiation. The Cho/NAA metabolic ratio was significantly increased in weeks 6, 7, and 8 following irradiation, compared to pre-radiation values. Vascular and glial injury appeared on 2 wk after RT in the histology samples, until 4 wk after RT, necrosis of the oligodendrocytes, neuronal degeneration and demyelination could be observed.

Conclusions

MRS is sensitive to detect metabolic changes following radiation, and can be used in the early diagnosis of radiation brain injury.     

Utility of chemical shift and diffusion-weighted imaging in characterization of hyperattenuating adrenal lesions at 3.0T

Objective

The purpose of our study was to evaluate the value of chemical shift imaging (CSI) and diffusion weighted imaging (DWI) at 3.0 T MRI in adrenal hyperattenuating lesions.

Methods

Fifty-one hyperattenuating adrenal lesions in 40 patients were evaluated. Signal intensity index (SII), adrenal to spleen ratio (ASR) and apparent diffusion coefficient (ADC) were used as quantitative analysis parameters.

Results

The mean SII, ASR and ADC values were: benign pheochromocytomas (n = 22), 7.04%; 0.96, 1.15 × 10⁻³ mm²/s; lipid-poor adenomas (n = 18), 33.77%, 0.71, 1.07 × 10⁻³ mm²/s; malignant tumors (n = 7), 11.24%; 1.00; 0.92 × 10⁻³mm²/s. There were significant differences between the lipid-poor adenomas and nonadenomas for SII and ASR, and there were significant differences between the benign and the malignant tumor ADC values. The optimal diagnostic threshold point of SII and ASR for lipid-poor adenomas was 11.96%, 0.83, the sensitivity and specificity were 88.9%, 97.5% and 97%, 83.3%. The optimal diagnostic threshold point of ADC value for benign lesions and malignant tumors was 1.04 × 10⁻³ mm²/s, the sensitivity and specificity were 61.4% and 85.7%.

Conclusion

Quantitative analysis of chemical shift MRI and DWI can help to characterize the hyperattenuating adrenal lesions, especially in differentiatiation between the lipid-poor adenomas, the benign pheochromocytomas, and the malignant tumors.     

Intravenous, contrast-enhanced MR colonography using air as endoluminal contrast agent: impact on colorectal polyp detection

Purpose

To compare diagnostic accuracy and patient tolerance of MR colonography with intravenous contrast and luminal air (MRC) to conventional colonoscopy (CC).

Materials and methods

IRB approval and written informed consent were obtained. Forty-six patients, both screening and symptomatic, underwent MRC followed by CC. The MRC technique employed 3D T1W spoiled gradient echo sequences performed after the administration of gadopenetate dimeglumine, with parallel imaging. The diagnostic accuracy and tolerance of patients for MRC was compared to CC.

Results

Twenty-four polyps were detected in eighteen patients with CC (5 polyps ≥10 mm, 4 polyps 6–9 mm, 15 polyps ≤5 mm). MRC was 66.7% (12/18) sensitive and 96.4% (27/28) specific for polyp detection on a per-patient basis. When analyzed by polyp size, sensitivity and specificity of MRC was 100% (5/5) and 100% (19/19), respectively, for lesions greater than 10 mm, 100% (4/4) and 100% (20/20) for lesions 6–9 mm, and sensitivity of 20% (3/15) lesions less than 5 mm. The sensitivity and specificity of MRC for detecting significant lesions (>6 mm) was 100% (9/9) and 100% (15/15), respectively. Regarding tolerance of the exams, there were no significant differences between MRC and CC. Thirty-five percent (n = 16) of patients preferred MRC as a future screening test compared to 33% (n = 15) for CC.

Conclusion

MRC using air as an intraluminal contrast agent is a feasible and well-tolerated technique for detecting colonic polyps ≥6 mm in size. Further studies are warranted.     

The role of ultrasound and magnetic resonance cholangiopancreatography for the diagnosis of biliary stricture after liver transplantation

Purpose

To identify the diagnostic value of ultrasound (US) and magnetic resonance cholangiopancreatography (MRCP) in diagnosing biliary strictures after liver transplantation.

Materials and methods

Sixty patients with clinically suspected biliary strictures after liver transplantation were retrospectively evaluated. All patients underwent US and MRCP before the standard of reference (SOR) procedure: endoscopic retrograde cholangiopancreatography or percutaneous transhepatic cholangiography. Radiological images were analyzed for biliary dilatation and strictures.

Results

By SOR, biliary dilatation was present in 55 patients, stricture in 53 (44 anastomotic, 4 intrahepatic, 5 both), and dilatation and/or stricture in 58. Dilatation was diagnosed by US and MRCP in 39 and 45, respectively (sensitivity 71% vs. 82%, p = 0.18). Stricture was diagnosed by US and MRCP in 0 and 42, respectively (sensitivity 0% vs. 79%, p < 0.0001). False positive stricture was diagnosed by MRCP in 2. Dilatation and/or stricture was diagnosed by US in 39 and MRCP in 50 (sensitivity 67% vs. 86%, p = 0.01); however, using both techniques, sensitivity increased to 95%.

Conclusions

MRCP is superior to US for diagnosing biliary strictures after liver transplantation primarily because MRCP can detect stricture. The combination of US and MRCP seems superior to either method alone. Our data suggest that in patients with normal US and MRCP, direct cholangiography could be avoided.     

"Hot cross bun" sign in multiple system atrophy with predominant cerebellar ataxia: a comparison between proton density-weighted imaging and T2-weighted imaging

Objective

To investigate whether proton density-weighted imaging can detect the “hot cross bun” sign in the pons in multiple system atrophy with predominant cerebellar ataxia significantly better than T2-weighted imaging at 3 T.

Methods

Sixteen consecutive patients with multiple system atrophy with predominant cerebellar ataxia according to the Consensus Criteria were reviewed. Axial unenhanced proton density-weighted imaging and T2-weighted imaging were obtained using a dual-echo fast spin-echo sequence at 3 T. Two neuroradiologists independently evaluated visualisation of the abnormal pontine signal using a 4-point visual grade from Grade 0 (no “hot cross bun” sign) to Grade 3 (prominent “hot cross bun” sign on two or more sequential slices). Differences in grade between proton density-weighted imaging and T2-weighted imaging were statistically analysed using the Wilcoxon signed-rank test.

Results

In 11 patients (69%), a higher grade was given for proton density-weighted imaging than T2-weighted imaging. In 1 patient (6%), grades were the same (Grade 3) on both images. In the remaining 4 patients (25%), signal abnormalities were not detected on either image (Grade 0). The “hot cross bun” sign was thus observed significantly better on proton density-weighted imaging than on T2-weighted imaging (P = 0.001).

Conclusions

The “hot cross bun” sign considered diagnostic for multiple system atrophy with predominant cerebellar ataxia is significantly better visualised on proton density-weighted imaging than on T2-weighted imaging at 3 T.     

Diffusion-weighted MRI versus transient elastography in quantification of liver fibrosis in patients with chronic cholestatic liver diseases

Purpose

To evaluate the diagnostic value of diffusion-weighted magnetic resonance imaging (DWMRI) and transient elastography (TE) in quantification of liver fibrosis in patients with chronic cholestatic liver diseases.

Materials and methods

Forty-five patients underwent DWMRI, TE, and liver biopsy for staging of liver fibrosis. Apparent diffusion coefficient (ADC) was calculated for six locations in the liver for combination of five diffusion sensitivity values b = 0, 50, 200, 400 and 800 s/mm². A receiver operating characteristic (ROC) analysis was performed to determine the diagnostic performance of DWMRI and TE. Segmental ADC variations were evaluated by means of coefficient of variation.

Results

The mean ADCs (×10⁻³ mm²/s; b = 0–800 s/mm²) were significantly different at stage F1 versus F ≥ 2 (p < 0.05) and F2 versus F4. However, no significant difference was found between F2 and F3. For prediction of F ≥ 2 and F ≥ 3 areas under the ROC curves were 0.868 and 0.906 for DWMRI, and 0.966 and 0.960 for TE, respectively. The sensitivity and specificity were 90.9% and 89.3% for F ≥ 2 (ADC ≤ 1.65), and 92.3% and 92.1% for F ≥ 3 (ADC ≤ 1.63). Segmental ADC variation was lowest for F4 (CV = 9.54 ± 6.3%).

Conclusion

DWMRI and TE could be used for assessment of liver fibrosis with TE having higher diagnostic accuracy and DWMRI providing insight into liver fibrosis distribution.     

Accurate fat fraction quantification by multiecho gradient-recalled-echo magnetic resonance at 1.5T in rats with nonalcoholic fatty liver disease

Aim

To assess the diagnostic accuracy of a new reconstruction technique for gradient-recalled-echo magnetic resonance (MR) sequences that provides a full decomposition of the water and fat content inside a voxel for nonalcoholic fatty liver disease (NAFLD) in rats.

Material and methods

Rats were randomized into two groups. A control group (n = 10) was given free access to regular dry rat chow for 4 weeks. The steatosis (n = 40) group was given free access to feed and water 4 days per week, and fasted for the remaining 3 days for 4 weeks. All rats were killed at 4 weeks and assessed for fatty infiltration and biochemical method.

Results

The average fat content using the gold standard method was 2.65 g (2.20–3.05) of fat/100 g liver for the control group and 4.14 g (1.95–8.60) of fat/100 g of liver for the overfed group (p < 0.05). The average fat-fraction obtained from the MR was 0.016 (0.01–0.02) for the control group and 0.057 (0.00–0.18) for the overfed group. The Pearson correlation coefficient between the samples was r² = 0.87.

Conclusion

Multi-echo MR is a good technique to quantify liver fat in rats.     

Non-perforating small bowel Crohn's disease assessed by MRI enterography: derivation and histopathological validation of an MR-based activity index

Objectives

To develop and validate a qualitative scoring system for enteric Crohn's disease activity using MR enterography (MRE).

Methods

MRE was performed in 16 patients (mean age 33, 8 male) undergoing small bowel resection. Mural thickness, T2 signal, contrast enhancement, and perimural oedema were scored qualitatively (0–3) at 44 locations. Transmural histopathological scoring of acute inflammation (AIS) was performed at all locations (score 0–13). MRI parameters best predicting AIS were derived using multivariate analysis. The MRI activity index was applied to 26 Crohn's patients (mean age 32, range 13–69 years, 15 male) and correlated to terminal ileal biopsy scores of acute inflammation (“eAIS” score 1–6). Receiver operator characteristic curves were calculated.

Results

Mural thickness (coefficient 1.34 (95% CI 0.36, 2.32)], p = 0.007) and T2 signal (coefficient 0.90 (95% CI −0.24, 2.04) p = 0.06) best predicted AIS (AIS = 1.79 + 1.34*mural thickness + 0.94*mural T2 score [R-squared 0.52]). There was a significant correlation between the MRI index and eAIS (Kendall's tau = 0.40, 95% CI 0.11–0.64, p = 0.02). The model achieved a sensitivity of 0.81 (95% CI 0.54–0.96), specificity of 0.70 (0.35–0.93) and AUC 0.77 for predicting acute inflammation (eAIS ≥2).

Conclusions

A simple qualitative MRI Crohn's disease activity score appears predictive against a histopathological standard of reference.     

Decreased hyperintense vessels on FLAIR images after endovascular recanalization of symptomatic internal carotid artery occlusion

Background and purpose

Hyperintense vessels (HV) on fluid-attenuated inversion recovery (FLAIR) images were assumed to be explained by slow antegrade or retrograde leptomeningeal collateral flow related to extracranial or intracranial artery steno-occlusion. The aim of this study was to investigate the effect of recanalization after endovascular therapy of symptomatic internal carotid artery (ICA) occlusion on the presence of HV.

Methods

Eleven patients with symptomatic ICA occlusion were retrospectively enrolled. Changes in the HV on FLAIR images were examined in affected hemisphere of each patient after successful treatment with endovascular recanalization (angioplasty, n = 3; stent-assisted angioplasty, n = 8). The relationship between postoperative changes in the HV and Thrombolysis In Cerebral Ischemia (TICI) scale (I-III) was assessed.

Results

After operation, HV of the 11 affected hemispheres were showed to be decreased (n = 3) or disappeared (n = 8) in treated side. The median interval between pre- and postoperative MRI examinations was 97.0 h (range, from 69. to 48.7 h). Of the 8 patients with disappeared HV, 7 achieved high TICI grade flow (III) and 1 had relatively low TICI grade flow (IIc) in treated side. However, all the 3 patients with decreased HV were found to be relatively low TICI grade flow (IIc).

Conclusion

Our data indicate that endovascular recanalization of ICA occlusion was effective for decreasing HV. Postoperative decrease in HV can be considered as a marker for hemodynamic improvement.     

Magnetic resonance myocardial perfusion imaging-First experience at 3.0T

Objective

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

Materials and methods

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

Results

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

Conclusion

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

Improvement of multislice oxygen-enhanced MRI of the lung by fully automatic non-rigid image registration

Purpose

In oxygen-enhanced magnetic resonance imaging of the lung (O2-MRI), motion artifacts related to breathing hamper the quality of the parametric O2-maps. In this study, fully automatic non-rigid image registration was assessed as a post-processing method to improve the quality of O2-MRI.

Materials and methods

Twenty healthy volunteers were investigated on a 1.5 T MR system. O2-MRI was obtained in four coronal sections using an IR-HASTE sequence with TE/TI of 12/1200 ms. Each section was repeatedly imaged during oxygen and room-air ventilation. Spatial differences among the images were corrected by fully automatic non-rigid registration. Signal variability, relative enhancement ratio between oxygen and room air images, and spatial heterogeneity of lung enhancement were assessed before and after image registration.

Results

Motion artifacts were corrected in 5–10 s. Non-rigid registration reduced signal variability of the source images and heterogeneity of the O2-maps by 1.1 ± 0.2% and 11.2 ± 2.9%, respectively (p < 0.0001). Registration did not influence O2 relative enhancement ratio (p = 0.06).

Conclusion

Fully automatic non-rigid image registration improves the quality of multislice oxygen-enhanced MRI of the lung.     

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.     

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

Objective

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

Methods and materials

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

Results

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

Conclusion

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

Thirty-nine cases of intracranial hemangiopericytoma and anaplastic hemangiopericytoma: A retrospective review of MRI features and pathological findings

Objective

To retrospectively review the imaging features of surgically and pathologically confirmed intracranial hemangiopericytoma and anaplastic hemangiopericytoma.

Methods

Thirty-nine cases of surgically and pathologically confirmed hemangiopericytoma and anaplastic hemangiopericytoma were analyzed retrospectively. The MRI features were compared with pathological findings in all cases.

Results

Of the 39 cases, 21 were anaplastic hemangiopericytoma (WHO grade III) and the remaining cases were hemangiopericytoma (WHO grade II); all lesions were solitary. MRI of anaplastic hemangiopericytoma showed that 20 cases were lobulated, and nine grew cross-leaf. The lesions showed mixed iso-high-low signal (n = 20) or iso-signal (n = 1) on plain T1WI, and mixed high-low signal (n = 20) or iso-signal (n = 1) on plain T2WI. After contrast injection, marked heterogeneous enhancement was seen in 19 cases. Significant necrosis and cystic changes were seen in 16 cases, and the “dural tail sign” was found in two cases. Ten cases had bony destruction, and 16 showed significant peritumoral edema. In 18 cases of hemangiopericytoma, nine were oval-shaped and three grew cross-leaf. The lesions showed mixed iso-low signal (n = 10) or iso-signal (n = 8) on plain T1WI, and mixed iso-high signal (n = 10) or iso-signal (n = 8) on plain T2WI. After contrast injection, significant uniform enhancement was seen in 10 cases. Significant necrosis and cystic changes were seen in seven cases, and “dural tail sign” was seen in six cases. Two cases had bony destruction. No case showed significant peritumoral edema. Pathological immunohistochemical Ki67 staining showed a concentration of ∼18.4% positive cells in anaplastic hemangiopericytoma, whereas in hemangiopericytoma it was 7.12%.

Conclusion

Imaging findings of intracranial anaplastic hemangiopericytoma had more pronounced lobulation, cross-leaf growth tendency, more and easier bleeding, more necrosis, more cystic changes giving rise to heterogeneous signals, rarer frequency of the “dural tail sign”, more damage near the skull, and more significant peritumoral edema than hemangiopericytoma. These features may help differentiate these two types of malignancy.     

Tolerability and diagnostic value of gadoteric acid in the general population and in patients with risk factors: results in more than 84,000 patients

Purpose

To review the tolerability and diagnostic effectiveness of gadoteric acid under daily practice conditions in the general population and at-risk patients.

Materials and methods

A total of 84,621 patients (45.4% men, 54.6% women, mean age 52.0 ± 16.9 years) were studied in 129 German centers. Patients underwent contrast-enhanced magnetic resonance imaging (MRI) using gadoteric acid (Gd-DOTA, Dotarem^®, Guerbet, Roissy CdG, France) as IV contrast medium (mean volume, 16.4 ml). 22.9% of the patients had at least one risk factor (e.g., allergies, previous allergic reaction to a contrast medium, and renal impairment). 554 patients received pretreatment before contrast medium administration (0.7%). Adverse events were documented and image quality was assessed.

Results

A diagnosis was possible in 99.7% of all cases. Image quality was rated good or excellent in 97.1%. Adverse events (e.g., nausea, vomiting, and urticaria) were observed in 0.34% of the examinations and were mostly rated as minor. There were 8 patients with serious adverse events. The adverse event rate was significantly higher in patients with a history of allergies (0.62%; p < 0.001) and in patients with a previous allergic reaction to contrast medium (1.23%; p < 0.001). There was no elevated incidence of adverse events in patients with renal impairment.

Conclusion

Gadoteric acid is a well-tolerated MRI contrast medium in patients with and without risk factors that is associated with a low rate of adverse events and good or excellent image quality in most patients.