Whole-body MRI of multiple myeloma: comparison of different MRI sequences in assessment of different growth patterns

Purpose

To determine sensitivity, specificity and inter-observer variability of different whole-body MRI (WB-MRI) sequences in patients with multiple myeloma (MM).

Methods and materials

WB-MRI using a 1.5 T MRI scanner was performed in 23 consecutive patients (13 males, 10 females; mean age 63 ± 12 years) with histologically proven MM. All patients were clinically classified according to infiltration (low-grade, n = 7; intermediate-grade, n = 7; high-grade, n = 9) and to the staging system of Durie and Salmon PLUS (stage I, n = 12; stage II, n = 4; stage III, n = 7). The control group consisted of 36 individuals without malignancy (25 males, 11 females; mean age 57 ± 13 years). Two observers independently evaluated the following WB-MRI sequences: T1w-TSE (T1), T2w-TIRM (T2), and the combination of both sequences, including a contrast-enhanced T1w-TSE with fat-saturation (T1 ± CE/T2). They had to determine growth patterns (focal and/or diffuse) and the MRI sequence that provided the highest confidence level in depicting the MM lesions. Results were calculated on a per-patient basis.

Results

Visual detection of MM was as follows: T1, 65% (sensitivity)/85% (specificity); T2, 76%/81%; T1 ± CE/T2, 67%/88%. Inter-observer variability was as follows: T1, 0.3; T2, 0.55; T1 ± CE/T2, 0.55. Sensitivity improved depending on infiltration grade (T1: 1 = 60%; 2 = 36%; 3 = 83%; T2: 1 = 70%; 2 = 71%; 3 = 89%; T1 ± CE/T2: 1 = 50%; 2 = 50%; 3 = 89%) and clinical stage (T1: 1 = 58%; 2 = 63%; 3 = 79%; T2: 1 = 58%; 2 = 88%; 3 = 100%; T1 ± CE/T2: 1 = 50%; 2 = 63%; 3 = 100%). T2w-TIRM sequences achieved the best reliability in depicting the MM lesions (65% in the mean of both readers).

Conclusions

T2w-TIRM sequences achieved the highest level of sensitivity and best reliability, and thus might be valuable for initial assessment of MM. For an exact staging and grading the examination protocol should encompass unenhanced and enhanced T1w-MRI sequences, in addition to T2w-TIRM.     

Role of diffusion-weighted imaging as an adjunct to contrast-enhanced breast MRI in evaluating residual breast cancer following neoadjuvant chemotherapy

Objective

To investigate whether the addition of diffusion-weighted imaging (DWI) to dynamic contrast-enhanced MRI (DCE-MRI) improves diagnostic performance in predicting pathologic response and residual breast cancer size following neoadjuvant chemotherapy.

Materials and methods

A total of 78 consecutive patients who underwent preoperative breast MRI with DWI following neoadjuvant chemotherapy were enrolled. DWI was performed on a 1.5 T system with b values of 0 and 750 s/mm. or on a 3 T system with b values of 0 and 800 or 0 and 1000 s/mm. The images on DCE-MRI alone, DWI alone, and DCE-MRI plus DWI were retrospectively reviewed. We evaluated the diagnostic performances of the three MRI protocols for the detection of residual cancer. The tumor size as predicted by MRI was compared with histopathologic findings. Apparent diffusion coefficient (ADC) values were also compared between the groups with and without residual cancer.

Results

Of the 78 patients, 59 (75.6%) had residual cancer. For detection of residual cancer, DCE-MRI plus DWI had higher specificity (80.0%), accuracy (91.0%), and PPV (93.2%) than DCE-MRI or DWI alone (P = 0.004, P = 0.007, and P = 0.034, respectively). The ICC values for residual cancer size between MRI and histopathology were 0.891 for DCE-MRI plus DWI, 0.792 for DCE-MRI, and 0.773 for DWI. ADC values showed no significant differences between residual cancer and chemotherapeutic changes (P = 0.130).

Conclusions

The addition of DWI to DCE-MRI significantly improved diagnostic performance in predicting pathologic response and residual breast cancer size after neoadjuvant chemotherapy.     

Diagnostic performance of breast MRI with and without the addition of quantitative diffusion weighted imaging

Objective

The purpose of our study was to investigate whether adding diffusion weighted imaging to dynamic contrast-enhanced MRI could improve the diagnostic performance of breast MRI.

Materials and methods

This retrospective study included 86 women with 93 primary and postoperative breast lesions detected on DCE-MRI who underwent subsequent biopsy. The diagnostic performance was calculated for DCE-MRI alone, combined DCE-MRI and quantitative DWI, and for quantitative DWI alone.

Results

Of the 93 lesions, 42 were benign and 51 malignant (5 DCIS, 41 IDC, 2 ILC, 3 NOS). Both DCIS (mean ADC = 1.17 ± 0.12 × 10⁻³ mm²/s) and IDC (mean ADC, 0.98 ± 0.14) exhibited lower mean ADC values than benign lesions (ADC value = 1.72 ± 0.36). Applying an ADC cutoff value of 1.33 increased the specificity and PPV of DCE-breast MRI from 59.5% and 75% to 78.5% and 83.3%, respectively. The specificity and PPV for quantitative DW-MRI alone (73.5% and 83.3%) were close to those broken out from the combined use of DCE and quantitative DW-MRI. However, the sensitivity and NPV of DWI remains lower than that of DCE-MRI.

Conclusion

DWI shows potential for improving the diagnostic performance of breast MRI and may reduce the number of unnecessary biopsies.     

Diagnostic accuracy of diffusion weighted MRI in cervical lymphadenopathy cases correlated with pathology results

Introduction

Diffusion weighted magnetic resonance imaging (DW MRI) is an imaging technique showing molecular diffusion. Cell size, density and integrity influence the signal intensity seen on diffusion-weighted images. This technique is a helpful complementary tool to distinguish tumoral from non tumoral tissue.The aim of this prospective study is to define the diagnostic accuracy of DWI to differentiate benign from malignant cervical lymph nodes.

Patients and methods

Twenty six patients who presented with 32 nodes were included in this study, 9 males (35.6%) and 17 females (65.4%). Their age ranged from: 6 to 76 years, mean age 45 ± 18.8 years referred to the radiology department of NCI, complaining of neck swelling, ultrasound showed cervical nodes.

Results

According to histopathological analysis we divided the examined lymph nodes (n = 32) into 2 categories: malignant lymph nodes 75% (n = 24) benign lymph nodes 25% (n = 8). DWI and ADC (apparent diffusion coefficient) values revealed 27 malignant lesions (84%), 5 benign (16%). The accuracy of the DWMRI was 89%. A significant difference between benign and malignant cervical nodes on DWI and on ADC maps is reported.The results obtained were 24 true positive, 3 false positive, 5 true negative. No false negative cases were identified, yielding a sensitivity of 100%, specificity of 62.5%, NPV = 100% and PPV = 89%. The difference between the mean ADC values between benign and malignant lesions was statistically significant (P < 0.0001).

Conclusion

MR diffusion imaging could be an important supportive tool in differentiation between benign and malignant lymph nodes, can to a lesser extent differentiate between the types of malignant lymphadenopathy and can be used as an indicator for improvement and recurrence post chemo and radiotherapy.     

Triple-phase dynamic MRI: A new clue to predict malignant transformation of giant cell tumor of bone

Objective

Our purpose was, through the comparison of the characteristics of time–intensity curve on triple-phase dynamic contrast-enhanced MRI among groups of giant cell tumor of bone (GCTB), recurrent benign giant cell tumor of bone (RBGCTB), and secondary malignant giant cell tumor of bone (SMGCTB), to find clues to predict the malignant transformation of GCTB.

Subjects and methods

21 patients diagnosed as GCTB were included in this study. All cases took recurrence after intralesional curettage. 9 cases were confirmed as SMGCTB and 12 cases were confirmed as RBGCTB. Cases were divided into four groups: group A, GCTB (n = 9); group B, SMGCTB (n = 9); group C, GCTB (n = 12); group D, RBGCTB (n = 12). Enhancement index(EI) of lesions on DCEMRI was calculated using formula: EI(t) = [S(t) − S(0)]/S(0), where S(0) was signal intensity of lesion on non-contrast-enhanced T1-weighted images and S(t) was signal intensity of lesion on DCEMRI (t = 30, 60, 180 s). Enhancement index of each group in each phase was compared using One-Way ANOVA analysis. Slope values of time–intensity curve were compared by the same way.

Results

Time–intensity curve of SMGCTB was characterized by a steep upward slope followed by an early and rapid washout phase. Time–intensity curve of GCTB and RBGCTB was characterized by a steep slope followed by a relatively slow washout phase. No significant difference in enhancement index was found in the first phase (p > 0.05). There was significant difference in the second and the third phase (p < 0.05). Enhancement index of group B (SMGCTB) was smaller. There was no difference in rising slope value (p > 0.05).

Conclusions

Dynamic contrast-enhanced MRI appears a helpful method to find new clues to predict malignant transformation of GCTB.     

Let's go out of the breast: Prevalence of extra-mammary findings and their characterization on breast MRI

Purpose

The aim of this study is to assess the prevalence, the site and the nature of extra-mammary findings on breast magnetic resonance imaging (MRI) and to determine its accuracy in the characterization of the discovered lesions.

Materials and methods

A retrospective review of 308 female patients (mean age 50 ± 20) who underwent breast MRI with 1.5 T device was performed. 125 out of 308 (40.5%) had a positive personal history of breast cancer (pre-operative n = 80; follow-up n = 45), while the remaining 183 without history of breast cancer (high familiar risk for breast cancer n = 80; dense breast n = 103). All incidental findings were characterized by means of additional imaging (US; Bone scintigraphy-MRI; CT-PET-CT).

Results

59 incidental findings were found in 53/308 (17%) examined patients. 9/59 incidental findings (15%) were confirmed to be malignant while the remaining 50/59 (84%) benign. The most common site was the liver (33/59; 55.8%), followed by the lung (6/59; 10.1%), bone (6/59; 10.1%), diaphragm (6/59; 10.1%) spleen (3/59; 5%), kidney (2/59; 3.4%), gall bladder (1/5; 1.5%), ascending aorta (1/59; 1.5%), thyroid (1/59; 1.5%). The incidence of malignant incidental findings resulted to be higher in the group of patients with personal breast cancer (36%) than in the other one (8%). By comparing MRI findings with the additional definitive imaging tools, breast MRI allowed a correct diagnosis in 58/59 cases with a diagnostic accuracy value of 98%.

Conclusion

Incidental extramammary findings on breast MRI are common. Benign lesions represent the most frequent findings, however malignant ones need to be searched especially in patients with personal history of breast cancer because they could influence the clinical patient management. Breast MRI can characterize incidental findings with high accuracy value.     

Value of diffusion weighted MRI in differentiating benign from malignant bony tumors and tumor like lesions

Aim of the work

To assess the value of diffusion weighted MRI in the differentiation of benign and malignant bony tumors and tumor like lesions.

Patients and methods

This study included 100 patients (66 males and 34 females). Their ages ranged between 4 and 65 years and the mean age was 31.3 years. The patients were referred to MRI unit from orthopedic surgery and radiotherapy departments and oncology center in Mansoura University hospital. These patients were selected on clinical bases indicating or suggesting presence of bony tumors or tumor-like lesions as a primary diagnosis (e.g. swelling or signs of inflammation). The commonest clinical presentations were pain (n = 71) and swelling (n = 61). Other presentations included limitation of movement (n = 20), back pain (n = 21) and fever (n = 20). More than one symptom may be present in one patient. Patients included in our study were classified according to the pathological and radiological criteria into three groups: Benign bone tumors (14 patients); malignant bone tumors (51 patients); tumor-like lesions (35 patients).

Results

DWI with measurement of ADC values helped in the differentiation of benign and malignant bone tumors, as malignant bone tumors have mean ADC values less than (1.31 × 10⁻³) mm²/s; while benign bone tumors have mean ADC values 1.43 × 10⁻³ mm²/s. Also, mean ADC values helped in differentiating malignant from inflammatory bony lesions as well as cystic from solid bony lesions.

Conclusion

DWI has been proven to be highly useful in the differentiation of benign, malignant bone tumors and tumor like bony lesions. Measurement of ADC values improves the accuracy of the diagnosis of bone tumors and tumor like lesions. Moreover, measurement of ADC values can be used in the follow up of tumors and their response to therapy.     

Infiltration patterns in monoclonal plasma cell disorders: correlation of magnetic resonance imaging with matched bone marrow histology

Objectives

To investigate how plasma cell infiltration patterns detected by MRI match the plasma cell distribution in bone marrow biopsy.

Methods

We assessed 50 patients with monoclonal plasma cell disorders of all clinical stages. MRI infiltration pattern was compared with matched BM histology from the same anatomic region.

Results

MRI revealed a minimal (n = 11, 22%), focal (n = 5, 10%), diffuse (n = 14, 28%) and mixed (n = 20, 40%) infiltration pattern. Diffuse MRI pattern was predominant in smoldering myeloma patients whereas the MRI patterns with “focal component” (i.e. focal and mixed) were most common in symptomatic myeloma (p < 0.01). In histology an interstitial (n = 13, 26%), nodular (n = 23, 46%) and packed marrow (n = 14, 28%) was found respectively. All three histological types of infiltration were observed in patients with diffuse and mixed MRI patterns. Minimal MRI pattern was found in all MGUS patients and was associated with an interstitial BM infiltration. In two patients with minimal MRI pattern an extensive micro-nodular BM infiltration was found in histology.

Conclusions

Infiltration patterns in MRI represent different histological growth patterns of plasma cells, but the MRI resolution is not sufficient to visualize micro-nodular aggregates of plasma cells.     

Dynamic contrast-enhanced MRI in patients with luminal Crohn's disease

Objectives

To prospectively assess dynamic contrast-enhanced (DCE-)MRI as compared to conventional sequences in patients with luminal Crohn's disease.

Methods

Patients with Crohn's disease undergoing MRI and ileocolonoscopy within 1 month had DCE-MRI (3T) during intravenous contrast injection of gadobutrol, single shot fast spin echo sequence and 3D T1-weighted spoiled gradient echo sequence, a dynamic coronal 3D T1-weighted fast spoiled gradient were performed before and after gadobutrol. Maximum enhancement (ME) and initial slope of increase (ISI) were calculated for four colon segments (ascending colon + coecum, transverse colon, descending colon + sigmoid, rectum) and (neo)terminal ileum. C-reactive protein (CRP), Crohn's disease activity index (CDAI), per patient and per segment Crohn's disease endoscopic index of severity (CDEIS) and disease duration were determined. Mean values of the (DCE-)MRI parameters in each segment from each patient were compared between four disease activity groups (normal mucosa, non-ulcerative lesions, mild ulcerative and severe ulcerative disease) with Mann–Whitney test with Bonferroni adjustment. Spearman correlation coefficients were calculated for continuous variables.

Results

Thirty-three patients were included (mean age 37 years; 23 females, median CDEIS 4.4). ME and ISI correlated weakly with segmental CDEIS (r = 0.485 and r = 0.206) and ME per patient correlated moderately with CDEIS (r = 0.551). ME was significantly higher in segments with mild (0.378) or severe (0.388) ulcerative disease compared to normal mucosa (0.304) (p < 0.001). No ulcerations were identified at conventional sequences. ME correlated with disease duration in diseased segments (r = 0.492), not with CDAI and CRP.

Conclusions

DCE-MRI can be used as a method for detecting Crohn's disease ulcerative lesions.     

Gadoxetic acid-enhanced 3.0 T MRI for the evaluation of hepatic metastasis from colorectal cancer: Metastasis is not always seen as a “defect” on the hepatobiliary phase

Purpose

To determine specific imaging features of hepatic metastasis from colorectal cancer, focusing on the hepatobiliary phase (HBP) of gadoxetic acid-enhanced MRI.

Materials and methods

Over a 2-year period, 79 hepatic metastatic lesions were identified from 32 patients (22 men and 10 women) who proven colorectal cancer and underwent gadoxetic acid-enhanced 3.0 T MRI. Hepatic metastases were proven pathologically in 16 patients: by surgical liver resection (n = 14) and by US-guided biopsy (n = 2). The remaining 16 patients were considered to have hepatic metastasis based on imaging studies and clinical information. Two radiologists evaluated the imaging features of each MRI sequence, including high resolution T2WI, dynamic contrast enhancement study with hepatobiliary phase, and diffusion weighted image. We also compared SI of the lesions on T2WI and HBP.

Results

T2WI showed homogeneous high SI (n = 25; 31.7%), target appearance (n = 3; 3.8%), reversed target appearance (n = 2; 2.6%), and heterogeneously high SI (n = 49; 62%). On HBP, homogeneous defect were seen in 22 lesions (27.9%), target appearance in five lesions (6.4%), reversed target appearance in two lesions (2.5%), and heterogeneous defect in 50 lesions (63.3%); including reticular (70%), partially globular (26%), and diffuse GGO-like (4%) patterns. According to the imaging features on HBP, the homogeneous defect and heterogeneous defect groups had a mean ADC value of 0.99 × 10⁻³ and 1.07 × 10⁻³ mm²/s, respectively, without statistically significant difference.

Conclusion

Hepatic metastasis from colorectal cancer usually showed as a heterogeneous defect on HBP and a heterogeneous high SI on T2WI. The generally accepted “true defect” was not a common finding in hepatic metastasis from colorectal cancer.     

Imaging features of intrahepatic cholangiocarcinoma in Gd-EOB-DTPA-enhanced MRI

Objective

The aim of this study is to describe the imaging features of intrahepatic cholangiocarcinoma in Gd-EOB-DTPA-enhanced MRI and to determine whether it results in improved tumour conspicuity of cholangiocarcinoma.

Materials and methods

Fifty-four patients with histologically proven intrahepatic cholangiocarcinoma underwent MRI of the liver using a 1.5 T MR-scanner with Gadoxetic acid disodium (Gd-EOB-DTPA; Eovist/Primovist, Bayer Healthcare, Berlin, Germany). The standard imaging protocol included a T2w multi-shot TSE sequence with fat saturation (fs), a T2w single shot sequence without fs and a T1w 3D GRE sequences with fs (unenhanced and arterial, portovenous, late venous and hepatobiliary phase). Two board certified radiologists experienced in liver MRI (5 and 10 years experience) evaluated retrospectively all MRI scans qualitatively and quantitatively. Signal was measured with region-of-interests (ROI) and signal-to-noise (SNR) as well as contrast-to-noise (CNR) was calculated. Statistical significance was tested with an ANOVA and a pairwise Wilcoxon rank test.

Results

All intrahepatic cholangiocarcinomas presented as hypointense lesions in the late venous and hepatobiliary phase. Images in the hepatobiliary phase showed the highest lesion conspicuity, i.e. n = 9 blurred (16.6%), n = 31 moderate (57.4%) and n = 14 sharp (26%). This was significantly higher than the lesion conspicuity of all other sequences or phases. Furthermore, the CNR was the highest in this sequence with 76.8 ± 51.3, with significantly higher values than the CNR of the unenhanced T1w sequence (CNR: 35.6 ± 21.0; p < 0.0001) and the arterial phase images (CNR: 53.6 ± 36.8; p < 0.001). The hepatobiliary phase images showed a SNR of 97.3 ± 59.7 (p < 0.001) and thus was significantly different from the unenhanced T1w sequence (SNR: 60.4 ± 35.3; p < 0.001), whereas the increase in SNR from the late venous to hepatobiliary phase was neglectable, indicating that no liver-specific contrast uptake is present in cholangiocarcinoma.

Conclusion

Intrahepatic cholangiocarcinoma presents as a hypointense lesion in Gd-EOB-DTPA-enhanced MRI in late venous phase images. The lesion conspicuity as well as CNR was highest in the hepatobiliary phase. Consequently, hepatobiliary phase images in Gd-EOB-DTPA-enhanced MRI images might be helpful for therapy planning due to the exact depiction of the tumour borders.     

IgG4-related kidney disease: MRI findings with emphasis on the usefulness of diffusion-weighted imaging

Objectives

To investigate the imaging findings of immunoglobulin G4 (IgG4)-related kidney disease (IgG4-KD) on magnetic resonance imaging (MRI) including diffusion-weighted imaging (DWI) and to evaluate the usefulness of DWI in lesion detection.

Methods

This retrospective cohort study included 31 patients with IgG4-KD who underwent MRI covering both kidneys. Two radiologists reviewed in consensus the MR images to determine the distribution pattern (location, laterality, and multiplicity) and the visually assessed signal intensity (hypointense, isointense or hyperintense) of the renal lesions compared to the normal renal parenchyma on each sequence. Per-patient sensitivity for detecting IgG4-KD and the number of detectable lesions were compared in T2-weighted images, DWI, and dynamic contrast-enhanced images.

Results

IgG4-KD typically manifested as bilateral (83.9%), multiple (93.5%), and renal parenchymal (87.1%) nodules appearing isointense (93.5%) on T1-weighted images, hypointense (77.4%) on T2-weighted images, hyperintense (100%) on DWI (b = 1000), and hypointense (83.3%) in the arterial phase and with a progressive enhancement pattern on dynamic contrast-enhanced images. The sensitivity of DWI for detecting IgG4-KD was significantly higher than that of T2-weighted images (100% vs. 77.4%, P = 0.034). The median number of detectable lesions was significantly greater in DWI (n = 9) than in T2-weighted images (n = 2) and dynamic contrast-enhanced images (n = 5) (P ≤ 0.008).

Conclusions

The characteristic MRI findings of IgG4-KD were bilateral, multiple, renal parenchymal nodules with T2 hypointensity, diffusion restriction, and a progressive enhancement pattern. As DWI was useful in the detection of IgG4-KD, adding DWI to conventional MRI for patients suspected of having IgG4-KD may enhance the diagnosis.     

Apparent diffusion coefficient measurements in the differentiation between benign and malignant neck masses

Aim

Evaluate the role of ADC value measurements in the differentiation between benign and malignant neck masses.

Methods

From April 2011 to February 2013, prospective study was conducted on 30 patients (17 male and 13 female), with the mean age 43.3 ± 6 years. Collected from wards and clinics of General Surgery and Otolaryngology Departments complaining from neck masses. MRI, Diffusion-Weighted Imaging (b value 0, 100, 500 and 1000 s/mm) and ADC value calculation were performed and the results were correlated with histopathological results and/or follow up.

Results

The present study include 30 patients (Lymphadenopathy {(n = 15) (11 as single entity), (4 associated with other entities)}, Focal thyroid swelling (n = 5), Salivary gland masses (n = 3) {Parotitis (1 case), Parotid carcinoma (2 cases)}, Nasopharyngeal masses (n = 5), Oropharyngeal masses (n = 2), Ludwig angina (n = 2) and Laryngeal masses (n = 2).The mean ADC of the malignant neck masses was (0.699 + 0.267 × 10^-3 mm²/s) while that of the benign masses was (1.879 + 0.751 × 10^-3 mm²/s).The results confirmed by biopsy in 23 cases and follow up (7 cases).The sensitivity, specificity, PPV, NPV and overall accuracy of quantitative diffusion WI in differentiating benign from malignant neck masses were 95.4%, 83.3%, 95.4%, 83%, and 92%.

Conclusion

ADC value calculation are promising noninvasive imaging approach that can be used in distinguishing between benign and malignant neck masses. Benign lesions have higher mean ADC values than malignant lesions, the cutoff value was 1.25 × 10^-3 mm²/s while 0.8 × 10^-3 mm²/s in thyroid lesions.     

Assessment of dynamic contrast-enhanced magnetic resonance imaging in the differentiation of malignant from benign orbital masses

Objective

Dynamic contrast enhanced MR imaging (DCE-MRI) allows imaging of the physiology of the microcirculation. The purpose of this study was to determine the diagnostic efficacy of time intensity curve (TIC) and DCE parameters for characterization of orbital masses.

Methods

Fifty-nine patients with untreated orbital lesions underwent DCE-MRI before surgery. For each lesion, peak height (PH), maximum enhancement ratio (ER_max), time of peak enhancement (T_peak) and maximum rise slope (Slope_max) were plotted and calculated. Receiver operator characteristics (ROC) analysis was conducted to assess the appropriate cut-off value.

Results

All 26 lesions that demonstrated persistent pattern (type-I) TICs were benign. Most of the masses with the washout pattern (type-III) TIC were malignant (10/14), including lymphoma (n = 6) and melanoma (n = 4). The Slope_max of benign lesions was statistically lower than malignant ones, while the ER_max and T_peak values of benign lesions were significantly higher. No statistical difference was found in PH (P = 0.121). The AUC for ER_max, T_peak and Slope_max in differentiating benign orbital lesions from malignant ones were 0.683, 0.837 and 0.738, respectively. In the three DCE parameters, Slope_max cut-off value of 1.10 provided the highest sensitivity of 93.8%; however, the corresponding specificity was low (58.1%). The ER_max cut-off value of 1.37 and T_peak cut-off value of 35.14 respectively offered the best diagnostic performances.

Conclusion

DCE-MRI, especially the qualitative TIC pattern and quantitative value of Slope_max, ER_max and T_peak, could be a complementary investigation in distinguishing malignant orbital tumor from benign ones.     

Pseudotumours in chronic kidney disease: Can diffusion-weighted MRI rule out malignancy

Objectives

To evaluate whether diffusion-weighted MRI (DW-MRI) can distinguish pseudotumours in chronic kidney disease (CKD pseudotumours) from renal-cell-carcinomas (RCCs) (with or without CKD) and whether it offers additional benefit over conventional MRI.

Methods

One-hundred patients underwent MDCT, MRI and DW-MRI (at b-values of 0 and 500 s/mm²) for evaluation of focal renal lesions. Of these, 20 patients with 40 CKD pseudotumours and 36 patients with 40 RCCs were retrospectively analyzed. T1-weighted, T2-weighted, diffusion-weighted images were evaluated, apparent-diffusion-coefficient (ADC) values were compared and receiver-operating-characteristic (ROC) curves were drawn to establish cut-off ADC-values.

Results

92.5% of CKD pseudotumours remained indeterminate after conventional MRI. On DW-MRI, none of them showed restricted diffusion and thus malignancy could be ruled out in 100% of the lesions. In contrast, all the solid RCCs showed diffusion restriction. Mean ADC-value for CKD pseudotumours was significantly higher than RCCs and surrounding diseased parenchyma [2.50 vs 1.56 (×10⁻³ mm²/s) (P < 0.0001) and 2.05 (×10⁻³ mm²/s) (P = 0.0001) respectively]. ROC analysis for differentiating CKD pseudotumours and RCC yielded high sensitivity (91.7%) and specificity (100%) for cut-off ADC-value of 2.04 (×10⁻³ mm²/s).

Conclusions

CKD pseudotumors usually remain indeterminate on conventional non-contrast MRI. DW-MRI can distinguish CKD pseudotumors from RCCs and offers a non-contrast non-invasive alternative for ruling out malignancy.     

Impact of liver cirrhosis on liver enhancement at Gd-EOB-DTPA enhanced MRI at 3 Tesla

Purpose

The purpose of this study was to assess differences in enhancement effects of liver parenchyma between normal and cirrhotic livers on dynamic, Gd-EOB-DTPA enhanced MRI at 3 T.

Materials and methods

93 patients with normal (n = 54) and cirrhotic liver (n = 39; Child–Pugh class A, n = 18; B, n = 16; C, n = 5) underwent contrast-enhanced MRI with liver specific contrast media at 3 T. T1-weighted volume interpolated breath hold examination (VIBE) sequences with fat suppression were acquired before contrast injection, in the arterial phase (AP), in the late arterial phase (LAP), in the portal venous phase (PVP), and in the hepatobiliary phase (HBP) after 20 min. The relative enhancement (RE) of the signal intensity of the liver parenchyma was calculated for all phases.

Results

Mean RE was significantly different among all evaluated groups in the hepatobiliary phase and with increasing severity of liver cirrhosis, a decreasing, but still significant reduction of RE could be shown. Phase depending changes of RE for each group were observed. In case of non-cirrhotic liver or Child–Pugh Score A cirrhosis mean RE showed a significant increase between AP, LAP, PVP and HBP. For Child–Pugh B + C cirrhosis RE increased until PVP, however, there was no change in case of B cirrhosis (p = 0.501) and significantly reduced in case of C cirrhosis (p = 0.043) during HBP.

Conclusion

RE of liver parenchyma is negatively affected by increased severity of liver cirrhosis, therefore diagnostic value of HBP could be limited in case of Child Pugh B + C cirrhosis.     

Diffusion tensor imaging differentiates vascular parkinsonism from parkinsonian syndromes of degenerative origin in elderly subjects

Background and Purpose

The etiologic diagnosis of parkinsonian syndromes is of particular importance when considering syndromes of vascular or degenerative origin. The purpose of this study is to find differences in the white-matter architecture between those two groups in elderly patients.

Materials and Methods

Thirty-five patients were prospectively included (multiple-system atrophy, n = 5; Parkinson's disease, n = 15; progressive supranuclear palsy, n = 9; vascular parkinsonism, n = 6), with a mean age of 76 years. Patients with multiple-system atrophy, progressive supranuclear palsy and Parkinson's disease were grouped as having parkinsonian syndromes of degenerative origin. Brain MRIs included diffusion tensor imaging. Fractional anisotropy and mean-diffusivity maps were spatially normalized, and group analyses between parkinsonian syndromes of degenerative origin and vascular parkinsonism were performed using a voxel-based approach.

Results

Statistical parametric-mapping analysis of diffusion tensor imaging data showed decreased fractional anisotropy value in internal capsules bilaterally in patients with vascular parkinsonism compared to parkinsonian syndromes of degenerative origin (p = 0.001) and showed a lower mean diffusivity in the white matter of the left superior parietal lobule (p = 0.01).Fractional anisotropy values were found decreased in the middle cerebellar peduncles in multiple-system atrophy compared to Parkinson's disease and progressive supranuclear palsy. The mean diffusivity was increased in those regions for these subgroups.

Conclusion

Clinically defined vascular parkinsonism was associated with decreased fractional anisotropy in the deep white matter (internal capsules) compared to parkinsonian syndromes of degenerative origin. These findings are consistent with previously published neuropathological data.     

Ex vivo MRI of axillary lymph nodes in breast cancer

Purpose

To provide a strategy for precise co-localization of lymph nodes on axillary lymph-node dissection (ALND) specimens both on pathology and MR.To identify nodal features suggestive of metastatic involvement on a node-to-node basis.

Materials and methods

National Institutional review-board approved this prospective study of 18 patients with breast cancer referred for ALND. Ex vivo T1 and inversion recovery (IR) T2 WI of ALND specimens tightly positioned within scaled plastic cranes was performed immediately after surgery. The correspondence of MR-based or pathologically based nodes location was assessed. The MR size and morphological presentation of metastatic and normal nodes were compared (Student's t-test or Mann–Whitney test). Quantitative variables were compared using Pearson coefficient.

Results

207 nodes were retrieved on pathology and 165 on MR. MR–pathological correlation of nodes location was high regarding MR-identified nodes (r = 0.755). An MR short axis threshold of 4 mm yielded the best predictive value for metastatic nodal involvement (Se = 78.6%; Sp = 62.3%). Irregular contours (Se = 35.7%; Sp = 96.7%), central nodal hyper-intensity on IR T2 WI (Se = 57.1%; Sp = 91.4%), and a cortical thickness above 3 mm (Se = 63.6%; Sp = 83.2%) were significantly associated with metastatic involvement.

Conclusion

Ex vivo MR allows node-to-node correlation with pathology. Morphological MR criteria can suggest metastatic involvement.     

Depiction and characterization of liver lesions in whole body [F]-FDG PET/MRI

Objectives

To assess the value of PET/MRI with [¹⁸F]-FDG using a whole body protocol for the depiction and characterization of liver lesions in comparison to PET/CT.

Methods

70 patients (31 women, 39 men) with solid tumors underwent [¹⁸F]-FDG PET/CT and followed by an additional PET/MRI using an integrated scanner. Two readers rated the datasets (PET/CT; PET/MRI) regarding conspicuity of hepatic lesions (4-point ordinal scale) and diagnostic confidence (5-point ordinal scale). Median scores for lesion conspicuity and diagnostic confidence were compared using Wilcoxon's rank sum test. Prior examinations, histopathology and clinical follow-up (116 ± 54 days) served as standard of reference.

Results

36 of 70 (51%) patients showed liver lesions. Using PET/CT and PET/MRI all patients with liver metastases could correctly be identified. A total of 97 lesions were found (malignant n = 26; benign n = 71). For lesion conspicuity significantly higher scores were obtained for PET/MRI in comparison to PET/CT (p < 0.001). Significantly better performance for diagnostic confidence was observed in PET/MRI, both for malignant as for benign lesions (p < 0.001).

Conclusions

PET/MRI, even in the setting of a whole body approach, provides higher lesion conspicuity and diagnostic confidence compared to PET/CT and may therefore evolve as an attractive alternative in oncologic imaging.     

Brain MR imaging abnormalities in pediatric patients after allogeneic bone marrow transplantation

Objective

Our aim was to analyze brain MRI findings in pediatric patients who developed neurologic complications after allogeneic bone marrow transplantation.

Materials and methods

This prospective study included 33 consecutive patients (age range from 3 to 18 years, mean 11.8 ± 5.1 years). They were referred to the MRI unit because of the neurological symptoms in the post transplant period. The underlying disorders included: non malignant hematological disorders (n = 20, 60.6%) and hematological malignancies (n = 13, 39.4%). Onset of the presentation of the complication in relation to the chronology of the transplant was identified in each patient (phase1: from days 0 to 30, phase 2: from days 30 to 100, and late phase after day 100).

Results

According to the MRI findings 6 patients (18.2%) showed normal examinations. Twenty-seven patients (81.8%) with positive MRI findings, are grouped into 7 main categories: posterior reversible encephalopathy syndrome (n = 16, 48.48%), intracranial hemorrhage (n = 2, 6.06%), cerebral venous sinus thrombosis (n = 1, 3.03%), CNS infection (n = 2, 6.06%), leukoencephalopathy (n = 5, 15.15%), mild atrophy (n = 11, 33.33%), CNS relapse (n = 1, 3.03%), with 9 patients having more than one diagnosis. Ten cases of PRES and 1 case of sinus thrombosis were detected in phase 1. Two cases of PRES and 2 cases of intracranial hemorrhage were detected in phase 2. Four cases of leukoencephalopathy, 4 cases of PRES, 2 cases of CNS infection, and 1 case of CNS relapse were detected in phase 3.

Conclusion

CNS complications after allogenic BMT in pediatric patients could cause a significant clinical problem. MRI can provide early diagnosis and follow-up to monitor treatment changes. Knowing the onset of the presentation of the complication in relation to the chronology of the transplant is important as it provides significant guidance on which causes to consider.