Value of renal resistive index in hepatitis C virus related liver cirrhosis and its response to midodrine

Background

Hyperdynamic circulatory state in liver cirrhosis is characterized by increased splanchnic blood flow and renal vasoconstriction.

Aim

To evaluate the relationship between renal resistive indices (RI) and HCV liver cirrhosis severity and RI value in predicting 6 month survival of those patients. Also we aimed to assess the effect of midodrine on RI.

Patients and methods

120 patients with HCV liver cirrhosis and 40 healthy controls were enrolled in the study. INR, total bilirubin, albumin, creatinine and sodium were measured in all patients. Both patients and controls underwent abdominal ultrasound with duplex Doppler examination of the kidneys with RI calculated. Patients were followed for 6 months. Surviving patients with highest risk underwent renal duplex with RI calculation (RI2). They then received oral midodrine at a dose of 7.5 mg three times daily for 3 months with revaluation of RI (RI3).

Results

57 (47.5%) patients had high RI (RI > 0.7) while 63 (52.5%) patients had normal RI. Patients had significantly higher RI than healthy controls (P < 0.001). There was a significant positive correlation between RI and MELD, MELD-Na, and Child class (r = 0.859, r = 0.769, rho = 0.56 respectively and P < 0.001). Patients with RI > 0.73 are at higher risk of death within 6 months (P < 0.001). Administration of midodrine resulted in no significant difference in RI in the 37 surviving patients with baseline RI > 0.73 (P = 0.1605).

Conclusion

RI is strongly correlated with liver cirrhosis severity and had comparable prognostic value with MELD score. Midodrine had no significant effect on RI in high risk patients.     

Kidney changes after extracorporeal shock wave lithotripsy: appearance on MR imaging

The occurrence of changes in the kidneys after extracorporeal shock wave lithotripsy (ESWL) was evaluated with magnetic resonance (MR) imaging in 34 patients, utilizing T1-weighted spin-echo pulse sequences. Five of the 34 patients underwent bilateral ESWL therapy before MR imaging. Of the 39 kidneys studied, 29 (74%) showed one or more changes on MR imaging: subcapsular or perinephric fluid (n = 10), focal (n = 16) or diffuse (n = 8) loss of the corticomedullary junction (CMJ), and focal areas of increased (n = 7) or decreased (n = 3) signal intensity. The CMJ changes were more prominent with increasing numbers of shock waves administered during the procedure. These relatively subtle changes detected on MR imaging may not be apparent with other imaging techniques. The long-term clinical significance of these findings is not yet known, although no apparent serious renal pathologic condition was detected.     

Reliability of ADC values in recognition of renal changes produced by extracorporeal shock wave lithotripsy (ESWL)

Objectives

To evaluate the reliability of diffusion-weighted imaging (DWI) in evaluating kidney changes after extracorporeal shock wave lithotripsy (ESWL) treatment for kidney stones.

Apparent diffusion coefficient of renal parenchyma and color Doppler ultrasound of intrarenal arteries in patients with cirrhosis related renal dysfunction

Objectives

The aim of this work was to study the renal hemodynamic changes which occur with liver cirrhosis using diffusion weighted magnetic resonance imaging (DW-MRI) and renal color duplex Doppler ultrasound.

Patients and methods

Patients were divided into four groups: Group A: 15 cirrhotic patients with compensated liver cirrhosis, Group B: 15 cirrhotic patients with refractory ascites, Group C: 15 cirrhotic patients with hepatorenal syndrome, Group D: 10 healthy persons as a control. The apparent diffusion coefficient (ADCs) of the kidneys was calculated using low b values (ADC_low) and high b values (ADC_high). Color Doppler ultrasound was performed in interlobar and arcuate arteries to calculate resistive index (RI) and pulsatility index (PI) in all patients.

Results

ADC_low showed a statistically significant difference between patients with hepatorenal syndrome and other groups. Using ADC_high no significant difference between different groups was noted. RI and PI of both interlobar and arcuate arteries were significantly higher in all the patient groups than the control group (P < 0.0001). RI and PI of both interlobar and arcuate arteries were significantly higher in patients with hepatorenal syndrome.

Conclusion

Liver cirrhosis, even in the presence of refractory ascites, did not affect the ADC value of renal parenchyma, however ADC value is affected in renal parenchyma of patients with hepato-renal syndrome. Duplex-Doppler ultrasound of intrarenal arteries enables the early detection of renal hemodynamic disturbances in patients with liver cirrhosis.     

Renal changes from extracorporeal shock-wave lithotripsy: evaluation using Doppler sonography

In this study, duplex Doppler sonography was used to evaluate flow changes within renal intraparenchymal vessels induced by extracorporeal shock-wave lithotripsy (ESWL). We have examined 20 patients with caliceal stones before, 1 h and 24 h after ESWL. Doppler waveforms were obtained both from arteries located near the stone and at least at 3 cm from it, and resistive index (RI) measured. A statistically significant increase of the RI (0.079 ± 0.039 mean increase; P < 0.001) was detected 1 h after ESWL in vessels located near the stone. After 24 h, RI tended to normalize (0.056 ± 0.037 mean decrease; P < 0.001). The residual difference (0.022 ± 0.043; P = 0.399) between mean RI values obtained near the stone before and 24 h after ESWL was mainly due to persistent elevated RI values in three patients with ESWL induced hydronephrosis. No significant RI changes were recognized in intraparenchymal vessels located far from the stone. In all patients, Doppler alterations were not associated with morphologic changes of renal parenchyma. Correspondence to: L. E. Derchi     

Evaluation of the relationship between renal function and renal volume-vascular indices using 3D power Doppler ultrasound

Purpose

To investigate the relationship between renal function and total renal volume-vascular indices using 3D power Doppler ultrasound (3DPDUS).

Materials and methods

One hundred six patients with hypertensive proteinuric nephropathy (HPN) (49 male, 57 female) and 65 healthy controls (32 male, 33 female) were evaluated prospectively using 3DPDUS. Total renal volume (RV), vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were calculated using Virtual Organ Computer-aided Analysis (VOCAL). The estimated glomerular filtration rates (GFRs) of the patients with HPN and the control group were calculated. The patients with HPN were divided into two groups on the basis of GFR, normal (≥90) or reduced (<90). Differences between groups were compared using ANOVA. Correlations between GFR, renal volume and vascular indices were analyzed using Pearson's correlation analysis. Significance was set at p < 0.05.

Results

The mean total RV, VI, FI and VFI values in the reduced GFR, normal GFR and control groups were RV (ml): 234.7, 280.7 and 294.6; VI: 17.6, 27.6 and 46.8; FI: 79.1, 88.7 and 93.9 and VFI: 7.1, 12.7 and 23.8. There were statistically significant differences between the groups (p < 0.001). Total RVs and vascular indices exhibited significant correlations with estimated GFR (r = 0.53–0.59, p < 0.001)

Conclusion

Three-dimensional power Doppler ultrasound is a reliable predictive technique in renal function analysis.     

Effect of gadolinium chelate contrast agents on diffusion weighted MR imaging of the liver, spleen, pancreas and kidney at 3 T

Purpose

To retrospectively test the null hypotheses that the qualitative appearance of DWI and the signal intensity values in DWI and corresponding ADC values of the liver, spleen, pancreas and kidneys are identical before and after the administration of gadolinium.

Materials and methods

Following IRB approval, DWI was acquired in 50 patients (25 male; mean age 54.9 years) prior to and after contrast administration, using single-shot echo planar imaging with b-values of 50 s/mm² and 800 s/mm² at 3 T. Binomial analysis was used to determine which image set was more significantly preferred in conveying the diffusion information. Pre- and post-gadolinium DWI and ADC values of corresponding regions of each organ were analyzed using standardized signal intensity measurements.

Results

Pre-contrast DWI images of the liver, spleen, and pancreas were preferred 52%, 49%, and 58%, respectively, with none of the differences being statistically significant. DWI of the kidneys was preferred on pre-contrast images in 83% (p < 0.001). In the liver and spleen, contrast caused a significant increase in the post-contrast DWI signal intensity values at b = 50 (p < 0.02) and b = 800 (p < 0.05) but had no statistically significant effect on the ADC value (p > 0.40). Pancreatic DWI signal intensity and ADC values pre- and post-contrast were also not significantly different (p = 0.489). In the renal parenchyma, significant decrease in the values of DWI at b = 50 (p < 0.01) and b = 800 (p < 0.01) as well as ADC (p < 0.02) was demonstrated following gadolinium administration.

Conclusion

Intravenous gadolinium administration does not make a statistically significant difference in the qualitative appearance or ADC measurements of the liver, spleen, or pancreas when comparing pre-contrast to post-contrast DWI. In the kidneys, however, ADC values are significantly lower post-contrast with the pre-contrast diffusion weighted images also being qualitatively preferred.     

Diffusion weighted MR imaging of pancreatic islet cell tumors

Purpose

The aim of our study is to demonstrate the feasibility of body diffusion weighted (DW) MR imaging in the evaluation of pancreatic islet cell tumors (ICTs) and to define apparent diffusion coefficient (ADC) values for these tumors.

Materials and methods

12 normal volunteers and 12 patients with histopathologically proven pancreatic ICT by surgery were included in the study. DW MR images were obtained by a body-phased array coil using a multisection single-shot echo planar sequence on the axial plane without breath holding. In addition, the routine abdominal imaging protocol for pancreas was applied in the patient group. We measured the ADC value within the normal pancreas in control group, pancreatic ICT, and surrounding pancreas parenchyma. Mann-Whitney U-test has been used to compare ADC values between tumoral tissues and normal pancreatic tissues of the volunteers. Wilcoxon Signed Ranks Test was preferred to compare ADC values between tumoral tissues and surrounding pancreatic parenchyma of the patients.

Results

In 11 patients out of 12, conventional MR sequences were able to demonstrate ICTs succesfully. In 1 patient an indistinct suspicious lesion was noted at the pancreatic tail. DW sequence was able to demonstrate the lesions in all of the 12 patients. On the DW images, all ICTs demonstrated high signal intensity relative to the surrounding pancreatic parenchyma. The mean and standard deviations of the ADC values (×10⁻³ mm²/s) were as follows: ICT (n = 12), 1.51 ± 0.35 (0.91-2.11), surrounding parenchyma (n = 11) 0.76 ± 0.15 (0.51-1.01) and normal pancreas in normal volunteers (n = 12), 0.80 ± 0.06 (0.72-0.90). ADC values of the ICT were significantly higher compared with those of surrounding parenchyma (p < 0.01) and normal pancreas (p < 0.001).

Conclusion

DW MR imaging does not appear to provide significant contribution to routine MR imaging protocol in the evaluation of pancreatic islet cell tumors. But it can be added to MR imaging protocol to detect the lesion in a limited number of patients with clinical suspicion for pancreatic ICT with negative or suspicious imaging findings.     

T2-weighted MR imaging of the liver: Qualitative and quantitative comparison of SPACE MR imaging with turbo spin-echo MR imaging

Objective

To qualitatively and quantitatively compare T2-weighted MR imaging of the liver using volumetric spin-echo with sampling perfection with application-optimized contrast using different flip angle evolutions (SPACE) with conventional turbo spin-echo (TSE) sequence for fat-suppressed T2-weighted MR imaging of the liver.

Materials and methods

Thirty-three patients with suspected focal liver lesions had SPACE MR imaging and conventional fat-suppressed TSE MR imaging. Images were analyzed quantitatively by measuring the lesion-to-liver contrast-to-noise ratio (CNR), and the signal-to-noise ratio (SNR) of main focal hepatic lesions, hepatic and splenic parenchyma and qualitatively by evaluating the presence of vascular, respiratory motion and cardiac artifacts. Wilcoxon signed rank test was used to search for differences between the two sequences.

Results

SPACE MR imaging showed significantly greater CNR for focal liver lesions (median = 22.82) than TSE MR imaging (median = 14.15) (P < .001). No differences were found for SNR of hepatic parenchyma (P = .097), main focal hepatic lesions (P = .35), and splenic parenchyma (P = .25). SPACE sequence showed less artifacts than TSE sequence (vascular, P < .001; respiratory motion, P < .001; cardiac, P < .001) but needed a longer acquisition time (228.4 vs. 162.1 s; P < .001).

Conclusion

SPACE MR imaging provides a significantly increased CNR for focal liver lesions and less artifacts by comparison with the conventional TSE sequence. These results should stimulate further clinical studies with a surgical standard of reference to compare the two techniques in terms of sensitivity for malignant lesions.     

Doppler-duplex ultrasound in renal colic

Objective: To determine the role of intrarenal Doppler ultrasound (US) in patients with renal colic and to establish the usefulness of this diagnostic method. Materials and methods: In 121 patients with renal colic and 70 healthy individuals, 382 kidneys were examined with color duplex US. Mean intrarenal-arterial resistive index (RI), and the difference of mean RIs (dRI) between both kidneys were determined. In 64 patients, RI and dRI were compared with urographic findings (time of delay pyelogram between both kidneys). Results: In the 70 healthy individuals, RI was 0.62 ± 0.045 and dRI 0.018 ± 0.01. In the 121 patients with renal colic, RI (0.71 ± 0.06) was significantly superior (P < 0.001) with respect to the opposite kidney, with a dRI of 0.09 ± 0.055. In a correlation performed in 64 patients with urographic findings among color doppler US, with a RI ≥ 0.70 and/or dRI ≥ 0.06 as an indicative value of obstruction, sensitivity and specifity were 91.8% for patients with delayed pyelogram (n = 37 patients), and 48.1% for patients with nondelayed pyelogram (n = 27 patients) with a specificity of 92.8% with respect to the group of normal patients. In the group of patients with delayed pyelogram, RI was significantly superior (P < 0.05) in patients with an evolution time greater than 24 hours, in patients with proximal ureteral obstruction and in patients who had signs of pyelonephritis. There were no significant differences in the group of patients with nondelayed pyelograms. Conclusion: Color Doppler US is useful to fundamentally evaluate the consequences of the obstruction on renal function. Other factors such as evolution time of the symptomology, obstruction level, or existence of pyelonephritis can alter the US-Doppler values.     

Non-enhanced MR angiography of renal artery using inflow-sensitive inversion recovery pulse sequence: A prospective comparison with enhanced CT angiography

Purpose

To prospectively evaluate the diagnostic value of non-enhanced inflow-sensitive inversion recovery (IFIR) MR angiography for the detection of renal artery stenosis (RAS), with enhanced CT angiography performed as the reference standard.

Materials and methods

Sixty consecutive patients suspected of RAS underwent both of IFIR MR and enhanced CT angiography. Subjective image quality, renal artery depiction and renal artery grading were all evaluated on artery-by-artery basis. Spearman rank correlation analysis was used to assess agreement between the two techniques. The diagnostic sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for RAS detection at IFIR MR angiography were calculated.

Results

One hundred twenty-six main renal arteries were visualized on enhanced CT and non-enhanced MR angiographic images, respectively. The Spearman rank correlation was 0.773 (P < .001) for renal artery depiction, 0.998 (P < .001) for renal arteries grading and 0.833 (P < .001) for RAS detection between the two modalities. The sensitivity, specificity, PPV and NPV of IFIR MR angiography for RAS detection demonstrated 100%, 99.0%, 92.0% and 100%, respectively.

Conclusion

Non-enhanced IFIR MR angiography had high sensitivity, specificity, PPV and NPV for RAS detection. It could be the first choice of renal artery imaging methods to avoid ionizing irradiation and renal toxicity from contrast media.     

Metastatic retropharyngeal lymph nodes: Comparison of CT and MR imaging for diagnostic accuracy

Purpose

The purpose of this study was to compare the diagnostic accuracies of CT and MR imaging for the detection of metastatic retropharyngeal lymph nodes (RLNs) in patients with nasopharyngeal and oropharyngeal squamous cell carcinoma (SCC).

Materials and methods

The study included 38 patients (28 men and 10 women; mean age, 65 years; age range, 48–82 years) with nasopharyngeal (n = 15) and oropharyngeal (n = 23) SCC who underwent both contrast-enhanced CT and MR imaging before chemoradiotherapy. RLNs were classified as malignant or benign on the basis of the results of follow-up MR imaging. Two radiologists independently evaluated the images for diagnosing metastatic RLNs.

Results

Among a total of 68 RLNs (minimum diameter, ≥4 mm) that were detected on gadolinium-enhanced fat-suppressed T1-weighted images, 30 (44%) were malignant and 38 (56%) were benign. The sensitivities of CT versus MRI were 60% versus 97% for observer 1 (p < 0.01) and 37% versus 90% for observer 2 (p < 0.01). The specificities of CT versus MRI were 92% versus 97% for observer 1 (p = 0.50) and 92% versus 100% for observer 2 (p = 0.25). The areas under the receiver operating characteristic curve (AUC) for CT versus MRI were 0.788 versus 0.996 for observer 1 (p < 0.01) and 0.693 versus 0.961 for observer 2 (p < 0.01).

Conclusion

MR imaging was superior to CT for the detection of metastatic RLNs.     

Diffusion weighted magnetic resonance imaging of kidneys in children with vesicoureteral reflux

Purpose

The apparent diffusion coefficient (ADC) which obtain from diffusion-weighted magnetic resonance imaging (DWI), is a quantitative parameter representing the renal function and parenchymal damage in some renal disorders. The primary aim of this study was to investigate whether renal tissue alterations associated with vesicoureteral reflux (VUR) can be displayed by DWI. The secondary aim was to assess how ADC values change with age in kidneys with and without VUR.

Materials and methods

This prospective study included 46 patients (8 boys, 38 girls; mean age 7.3 ± 4.2; range 1–15 years) with VUR and 54 control subjects (21 boys, 33 girls; mean age 7.7 ± 5.2; range 1–17 years). All subjects underwent DWI of the kidneys using b value of 600 s/mm² in addition to MR urography. The ADC values of 71 kidneys with VUR were compared with those of 81 kidneys without VUR.

Results

The mean ADC values were (1.93 ± 0.36) × 10⁻³ mm²/s, (1.97 ± 0.24) × 10⁻³ mm²/s, (1.83 ± 0.37) × 10⁻³ mm²/s, (1.98 ± 0.20) × 10⁻³ mm²/s and (2.08 ± 0.42) × 10⁻³ mm²/s in normal kidneys, and in those with grade 1, grade 2, grade 3 and grade 4 VUR, respectively. There was no significant difference in ADC values between kidneys with and without VUR. There was a significant positive correlation between the age and ADC values both in kidneys with and without VUR (r = 0.79, p < 0.001 and r = 0.82; p < 0.001, respectively).

Conclusion

DWI does not reveal probable parenchymal alterations in reflux nephropathy. ADC values increase with age during childhood not only in normal kidneys but also in kidneys with VUR.     

Effects of lithotripsy on rat kidney: evaluation with MR imaging, histology, and electron microscopy

Magnetic resonance (MR) imaging at 1.5 T was used to evaluate the effects of extracorporeal shock wave lithotripsy (ESWL) in 30 rats and the findings on T1- and T2-weighted (spin echo 600/22, 1,600-2,000/90) images were compared with histology and scanning microscopy. The observed pathologic changes increased in severity with the number of shock waves given (500-5,000 15 kV). Post-ESWL MR findings in 54 kidneys included perirenal and subcapsular fluid (n = 30), diffuse loss of corticomedullary junction definition (n = 28), intrarenal foci of increased (n = 7) or decreased (n = 6) signal intensity, focal indentation of the renal contour (n = 5), and loss of distinction between the renal, splenic, or hepatic contour (n = 7). The subcapsular and intrarenal findings corresponded pathologically to areas of hemorrhage and hematoma formation--the contour changes to foci of renal scarring or perirenal adhesions. Electron microscopy demonstrated marked alterations of the renal tubules and vasculature. The study shows the feasibility of assessing the nature and chronology of renal damage post-ESWL in a rat model by MR.     

The detection of coronary stiffness in cardiac allografts using MR imaging

Objective

To test the hypothesis that biomechanical changes are quantitatively related to morphological features of coronary arteries in heart transplant (HTx) recipients.

Materials and methods

With IRB approval, three-dimensional (3D) magnetic resonance (MR) angiography and two-dimensional (2D) black-blood stead-state free precession (SSFP) MR imaging were performed to image coronary arteries of 36 HTx patients. Contours of coronary wall were manually drawn. For each coronary segment, coronary wall thickness, wall area, lumen area (in systole and diastole) were acquired. Coronary distensibility index (CDI) and the percent of the coronary wall occupying the vessel area (PWOV) were calculated.

Results

There are totally 98 coronary segments eligible for quantitative analysis from 27 HTx patients. The CDI is 4.90 ± 2.44 mmHg⁻¹. The mean wall thickness is 1.49 ± 0.24 mm and the PWOV is 74.6% ± 7.5%. CDI has moderate correlations with wall thickness (r = −0.531, P < 0.001) and with PWOV (R = −0.435, P < 0.001).

Conclusions

Detected with coronary MR imaging, CDI is quantitatively correlated with the morphological features of the coronary artery in HTx patients. Coronary stiffness has the potential to become an alternative imaging biomarker for the quantitative assessment of the status of cardiac allografts.     

3D dynamic pituitary MR imaging with CAIPIRINHA: Initial experience and comparison with 2D dynamic MR imaging

Objectives

To evaluate the validity of 3D dynamic pituitary MR imaging with controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA), with special emphasis on demarcation of pituitary posterior lobe and stalk.

Methods

Participants comprised 32 patients who underwent dynamic pituitary MR imaging due to pituitary or parasellar lesions. 3D dynamic MR with CAIPIRINHA was performed at 3 T with 20-s-interval, precontrast, 1st to 5th dynamic images. Normalized values and enhanced ratios (dynamic postcontrast image values divided by precontrast ones) were compared between 3D and 2D dynamic MR imaging for patients with visual identification of posterior lobe and stalk.

Results

In 3D, stalk was identified in 29 patients and unidentified in 3, and posterior lobe was identified in 28 and unidentified in 4. In 2D, stalk was identified in 26 patients and unidentified in 6 patients, and posterior lobe was identified in 15 and unidentified in 17. Normalized values of pituitary posterior lobe and stalk were higher in 3D than 2D (P < 0.001). No significant difference in enhancement ratio was seen between 3D and 2D.

Conclusions

3D dynamic pituitary MR provided better identification and higher normalized values of pituitary posterior lobe and stalk than 2D.     

Magnetic resonance imaging of renal involvement in genetically studied patients with tuberous sclerosis complex

Purpose

To evaluate renal involvement in tuberous sclerosis complex (TSC).

Materials and methods

A series of 24 TSC patients (19 with genetically demonstrated disease), underwent abdominal 1.0-T MR imaging with axial/coronal T1- and T2-weighted scans, with/without fat saturation. We looked for angyomiolipomas (AMLs) and cysts in 47 kidneys of 24 patients. We evaluated the percentage of parenchymal involvement by manual contouring on the coronal scans in 39 kidneys of 20 patients.

Results

We detected AMLs in 15/24 (63%) patients and in 27/47 (57%) kidneys, cysts in 14/24 (58%) and in 26/47 (55%); respectively. AMLs were found in 2/4 TSC1 and in 11/15 TSC2 patients, cysts were found in 2/4 TSC1 and in 9/15 TSC2 patients. The global renal involvement ranged from 0 to 32% (median, 18%) in TSC1 and from 0 to 100% (median, 39%) in TSC2 patients. A fair correlation (r = .464) was found between patient’s age and renal involvement, a good correlation (r = 0.655) between renal involvement and creatinine clearance.

Conclusion

Renal parenchyma of TSC patients can be evaluated with MR imaging. A detectable renal involvement was found in 83% of patients, higher in TSC2 than in TSC1. Renal function seems to correlate with renal involvement quantified with MR imaging.     

Necrotic cervical nodes: Usefulness of diffusion-weighted MR imaging in the differentiation of suppurative lymphadenitis from malignancy

Purpose

The purpose of this study was to assess the efficacy of diffusion-weighted (DW) MR imaging for the differentiation between suppurative lymphadenitis and malignancy in necrotic cervical lymph nodes.

Materials and methods

Fifteen patients with suppurative lymphadenitis, 40 with squamous cell carcinoma (SCC), eight with lymphoma, and six with thyroid cancer were accompanied by necrotic cervical nodes. All 69 patients underwent 1.5-T MR imaging including DW and 58 underwent gadolinium-enhanced MR imaging. Necrotic area-to-spinal cord signal intensity ratios (SIR) on T1-, T2- and DW images and apparent diffusion coefficients (ADCs) [10⁻³ mm²/s] were correlated with the pathologies.

Results

Nineteen necrotic cervical nodes with suppurative lymphadenitis, 67 with SCC, 10 with lymphoma, and 12 with thyroid cancer were identified. SIR on DW images was higher in suppurative lymphadenitis (2.50 ± 1.21) than in malignancies (1.29 ± 0.67) (p < .01), and ADC value was lower in suppurative lymphadenitis (0.89 ± 0.21) than in malignancies (1.46 ± 0.46) (p < .01). SIR on T1-weighted images was higher in thyroid cancer (1.95 ± 0.53) than in suppurative lymphadenitis (0.87 ± 0.17), SCC (0.92 ± 0.13), and lymphoma (0.95 ± 0.09) (p < .01). No significant difference in SIR on T2-weighted images was found between suppurative lymphadenitis (1.46 ± 0.50) and malignancies (1.61 ± 0.56).

Conclusion

DW imaging with ADC measurements may play a supplementary role in the differentiation of necrotic cervical nodes between suppurative lymphadenitis and malignancy.     

Tumor tissue characterization evaluating the luciferase activity under the control of a hsp70 promoter and MR imaging in three tumor cell lines

We investigated the luciferase activity under the control of a hsp70 promoter and MR imaging for three tumor cell lines. Three tumor cell lines, SCCVII, NIH3T3 and M21 were transfected with a plasmid containing the hsp70 promoter fragment and the luciferase reporter gene and grown in mice. Bioluminescence imaging of the tumors was performed every other day. MR imaging, pre- and post-contrast T1-wt SE, T2-wt FSE, Diffusion-wt STEAM-sequence, T2-time determination were obtained on a 1.5-T GE MRI scanner at a tumor size of 600–800 mm³ and 1400–1600 mm³. Comparing the different tumor sizes the luciferase activity of the M21 tumors increased about 149.3%, for the NIH3T3 tumors about 47.4% and for the SCCVII tumors about 155.8%. Luciferase activity of the M21 tumors (r = 0.82, p < 0.01) and the SCCVII tumors (r = 0.62, p = 0.03) correlated significant with the diffusion coefficient. In the NIH3T3 tumors the best correlation between the luciferase activity and the MRI parameter was seen for the SNR (T2) values (r = 0.78, p < 0.01). The luciferase activity per mm³ tumor tissue correlated moderate with the contrast medium uptake (r = 0.55, p = 0.01) in the M21 tumors. In the NIH3T3 and SCCVII tumors a negative correlation (r = −0.78, p < 0.01, respectively, r = −0.49, p = 0.02) was found with the T2 time. Different tissue types have different luciferase activity under the control of the same hsp70 promoter. The combination of MR imaging with bioluminescence imaging improves the characterization of tumor tissue giving better information of this tissue on the molecular level.     

Detection of prostate cancer: Utility of diffusion-weighted MR imaging and 3D MR spectroscopic imaging

Purpose

To prospectively compare the mean ADC generated from DWI, the mean choline + creatine/citrate ratio generated from 3D MRS and the combined mean ADC and mean choline + creatine/citrate ratio in the detection of prostate cancer, and to correlate between the choline + creatine/citrate ratio and the aggressiveness of malignancy determined by Gleason score, with histopathological examination of the excised gland as the reference standard.

Patients and methods

Forty-six patients with biopsy-proved cancer underwent pre-operative MRI at 1.5 T. Axial T1, axial, coronal and sagittal T2-weighted, diffusion-weighted and 3D MRS using a point-resolved spectroscopic sequence (PRESS) were acquired. The mean ADC, mean choline + creatine/citrate ratio and combined parameters for malignant lesions are correlated with the pathological results. For each malignant lesion choline + creatine/citrate ratio was correlated with the aggressiveness of malignancy determined by Gleason score. Receiver operating characteristic (ROC) curves were used to determine sensitivity, and specificity of the studied parameters, and Kappa measures of agreement were calculated for prostate cancer detection.

Results

The mean ADC for tumor tissue was 1.0 ± 0.22 × 10⁻³ mm²/s (mean ± SD), and was significantly lower than that for non-tumor tissue 1.44 ± 0.28 × 10⁻³ mm²/s (p < 0.001). For MRS study the mean (choline + creatine)/citrate ratio in tumor tissue was 1.98 ± 1.0, and was significantly higher than that for non-tumor tissue, 0.72 ± 0.39 (p < 0.001). By combining both ADC values and (choline + creatine)/citrate ratio for differentiating malignant from non-malignant tissues a receiver operating characteristic analysis (ROC) curve showed Area under curve (AUC = 0.93) and was significantly higher than either (choline + creatine)/citrate ratio alone (AUC = 0.86) (p < 0.001) or ADC value alone (AUC = 0.89) (p < 0.001). There is an increasing (choline + creatine)/citrate ratio with increasing Gleason score, however, there is overlap between groups. A greater sensitivity of MRS for tumor detection 85% and 92% was present for tumors with Gleason score 4 + 3 and ?4 + 4, respectively, while for tumors with Gleason score 3 + 3 the sensitivity was 63%.

Conclusion

The combination of ADC and (choline + creatine)/citrate ratio is better than each parameter alone in differentiating between tumor and non-tumor prostatic tissue, also MR spectroscopic imaging findings of prostate tumor (Cho + Cr)/Cit ratio correlate with pathologic Gleason score. The combined parameters offer a promising non-invasive method for the diagnostic workup of prostate cancer.