Characterization of liver hemangiomas with pulse inversion harmonic imaging

The purpose of this study was to determine if pulse inversion harmonic imaging (PIHI) can characterize liver hemangiomas. We retrospectively evaluated 39 consecutive patients with liver hemangiomas, 20 typical on conventional US (hyperechoic, homogeneous, or slightly inhomogeneous and with sharp margins) and 19 atypical (11 inhomogeneous with different echogenicity larger than 3 cm, 6 hypoechoic, and 2 isoechoic smaller than 3 cm). Each liver hemangioma was firstly evaluated by PIHI and then confirmed by dynamic helical CT (28 patients) or by 6 months of US follow-up (11 patients). The PIHI was performed by two distinct sweeps on a marker lesion, 30 s (vascular phase) and from 3 to 5 min (late phase) after bolus injection of Levovist (2.5 g, 300 mg/ml). Scans were digitally stored and reviewed using a dedicated software. Contrast enhancement features of marker lesion were subjectively evaluated. Typical hemangiomas on conventional US revealed on PIHI a characteristic rim-like or peripheral globular enhancement on 30-s scan in 4 of 20 cases (20%) and a characteristic isoechoic pattern on late phase in 16 of 20 cases (80%). On PIHI, all (11 of 11) atypical hemangiomas larger than 3 cm and 4 of 8 atypical liver hemangiomas smaller than 3 cm revealed a characteristic rim-like or peripheral globular enhancement on vascular phase with a characteristic centripetal fill-in on late phase. In 4 of 8 atypical liver hemangiomas smaller than 3 cm no characteristic pattern was revealed by PIHI. Pulse inversion harmonic imaging revealed a typical pattern in the majority of liver hemangiomas typical and atypical on conventional US. In few liver hemangiomas atypical on conventional US PIHI did not identify a characteristic pattern and helical CT was necessary for final characterization.     

Detection of liver metastases by pulse inversion harmonic imaging during Levovist late phase: comparison with conventional ultrasound and helical CT in 160 patients

The aim of this study was to evaluate capabilities of pulse inversion harmonic imaging (PIHI) with Levovist in detection of liver metastases compared with conventional ultrasound (US) and helical CT (HCT). One hundred sixty consecutive patients with known malignancies were evaluated by conventional US, PIHI 2 min (40 patients) or 4 min (120 patients) after Levovist injection and HCT. Conspicuity and number of the identified metastatic lesions were evaluated and assessed by statistical analysis (significance p<0.05). Mean diameter of the smallest identified metastases was computed for conventional US, PIHI and HCT. In cases where PIHI revealed more lesions suspicious for metastases than HCT, intraopertive US with surgical biopsy or 3–6-month US follow-up were performed to confirm diagnosis. Images were stored on magneto-optical disk and evaluated off-line by a dedicated software. Metastases conspicuity was significantly improved on PIHI if compared with conventional US (p<0.05). In 49 patients all the employed imaging techniques did not reveal any lesion, whereas in the remaining 111 patients, 28 patients revealed more than five metastatic lesions and 83 patients presented from one to five metastatic lesions. In comparison with conventional US, PIHI revealed more metastases in 39/83 (47%), the same number in 44/83 (53%) and a lower number in 0/83 (0%) patients. In comparison with HCT, PIHI revealed more metastases in 10/83 (12%), the same number in 61/83 (74%) and a lower number in 12/83 (14%) patients. Average number ± SD (standard deviation) of confirmed metastases for patients was 2.21±1.6 for conventional US, 3.1±2.44 for PIHI and 3.05±2.41 for HCT. The difference between PIHI and conventional US was statistically significant (p<0.0001), whereas the difference between PIHI and HCT was not significant (p=0.9). The smallest identified metastases presented 3-mm mean diameter on PIHI, 5-mm on HCT and 7-mm on conventional US. PIHI with Levovist is a reliable technique in metastases detection. Electronic Publication     

Characterization of renal tumours with pulse inversion harmonic imaging by intermittent high mechanical index technique: initial results

Our objective was to evaluate whether contrast-specific ultrasound (US) technique pulse inversion harmonic imaging (PIHI) with Levovist could reveal differential morphological features in solid and cystic renal masses. Twenty-six renal masses in 26 patients were evaluated by PIHI after Levovist injection with intermittent high mechanical index stimulation, performed every 10–15 s during arterial and delayed phase. Helical CT (HCT; n=6) or histological findings on surgical/bioptic specimen (n=20) were considered as the reference procedures for definitive diagnosis. Eleven solid renal cell carcinomas (RCCs), 1 embryonal matanephric adenoma (EMA), 7 angiomyolipomas (AMLs), 4 cystic RCCs and 3 complex inflammatory cysts were identified. Solid RCCs revealed a much higher (p<0.05) contrast enhancement than AMLs with typical pattern on conventional US (n=6). The EMA and AML with atypical pattern on conventional US (n=1) revealed intense contrast enhancement during arterial phase, progressively decreasing during delayed phase. Cystic RCCs and complex inflammatory cysts revealed intense contrast enhancement on the peripheral thick wall during arterial phase decreasing on delayed phase. The PIHI has been shown to differentiate solid RCC from typical AML by contrast enhancement assessment after Levovist injection, but differential diagnosis both in solid and in cystic renal masses still remains difficult. Electronic Publication     

Benign focal liver lesions: spectrum of findings on SonoVue-enhanced pulse-inversion ultrasonography

The prevalence of benign focal liver lesions (BFLL) is high both in the general population and in patients with known malignancies. The gray-scale ultrasound (US) technique is usually the first-line imaging modality used in the radiological workup of such lesions, but unfortunately it lacks specificity. Furthermore, Doppler examination may often be unsatisfactory owing to motion artefacts, or when small or deeply located lesions are evaluated. Recently, microbubble-based contrast agents used in combination with gray-scale US techniques, which are very sensitive to nonlinear behavior of microbubbles, have led to a better depiction of both microvasculature and macrovasculature of focal hepatic masses, thus improving the reliability of using US in the assessment of liver tumors. This review illustrates the spectrum of enhancement patterns of BFLL on contrast-enhanced ultrasonography with SonoVue, a second-generation microbubble-based contrast agent.This paper is based on a work accepted for presentation as a scientific paper at the Scientific Assembly and Annual Meeting of the ECR 2004.     

Centrifugal (inside-out) enhancement of liver hemangiomas: a possible atypical appearance on contrast-enhanced US

OBJECTIVE: To report the prevalence and to describe the atypical centrifugal (inside-out) appearance of contrast-enhancement of liver hemangiomas on contrast-enhanced sonography. MATERIALS AND METHODS: Baseline and SonoVue-enhanced ultrasonography of 92 patients with 158 liver hemangiomas - considered atypical at grey-scale examination and confirmed by computed tomography, magnetic resonance imaging and ultrasound follow-up - were reviewed in consensus by two experienced radiologists, who evaluated baseline echogenicity and the dynamic enhancement pattern of each lesion looking for the presence of central enhancing foci in the arterial phase followed by a centrifugal (inside-out) enhancement in the portal-venous and late phases. RESULTS: After administration of SonoVue, 12/158 hemangiomas (7.6%) (size range: 1-7cm; mean: 3.2cm) in seven patients (5 women, 2 men; age range: 34-71 years, mean: 50.8 years) showed a central enhancing focus in the arterial phase followed by a centrifugal enhancement in the portal-venous and late phases. In all cases centrifugal enhancement was incomplete at contrast-enhanced sonography, whereas computed tomography and/or magnetic resonance imaging were able to depict a complete and homogeneous fill-in. CONCLUSION: Radiologist should be aware that centrifugal (inside-out) appearance on contrast-enhanced sonography is a rare but possible feature of liver hemangioma.     

Liver haemangiomas undetermined at grey-scale ultrasound: contrast-enhancement patterns with SonoVue and pulse-inversion US

The objective of this study was to describe the spectrum of contrast-enhancement patterns of hepatic haemangiomas undetermined at grey-scale ultrasound (US) on SonoVue-enhanced pulse-inversion (PI) US. Twenty patients (11 women, nine men) with 35 haemangiomas (size range: 1–7 cm; mean: 3.1 cm) undetermined at baseline US underwent PI at low M.I. (0.05–0.08) after i.v. injection of SonoVue. All haemangiomas were confirmed by typical helical computed tomography (CT) and/or magnetic resonance imaging (MRI) findings. US examinations were videotaped and then reviewed by two experienced radiologists blinded to the final diagnosis. Readers evaluated by consensus the baseline echogenicity and the dynamic enhancement pattern of each lesion, in comparison with adjacent liver parenchyma. After administration of SonoVue, 31/35 (88%) haemangiomas showed peripheral hyperechoic nodules in the arterial phase, followed by progressive centripetal fill-in, which was complete in 25/35 cases and incomplete in 6/35 cases. Three out of 35 (9%) haemangiomas showed rapid and complete fill-in in the arterial phase, which persisted in the portal and delayed phases. Finally, 1/35 haemangiomas (3%) showed a rim of arterial contrast enhancement with progressive and complete centripetal fill-in in portal-venous and delayed phases. In conclusion, PI after the administration of SonoVue enabled the depiction of typical contrast-enhancement patterns in haemangiomas undetermined at baseline US.     

Signal changes in liver and spleen after Endorem administration in patients with and without liver cirrhosis

The goal of this study was to compare the effect of Endorem on the signal intensity of the spleen in patients with normal liver tissue and in patients with liver cirrhosis. Thirty patients with normal liver tissue and 47 with liver cirrhosis were examined before and after i. v. Endorem administration. The patients were examined with a 1.5-T magnet system (Magnetom Vision) using a semiflexible cp-array coil. Three different pulse sequences were used: a T1-weighted gradient-echo sequence, a T2-weighted fast spin-echo sequence with spectral fat suppression, and a T2^*-weighted gradient-echo sequence. The signal-to-noise ratios (SNRs) of two areas of the liver and spleen were determined. The mean SNRs of the liver and spleen in patients with and without liver cirrhosis were compared. For assessment of statistical significance, the t-test at a level of P < 0.05 was applied. After i. v. administration of Endorem, no differences were seen with the T1-weighted gradient-echo sequence for the liver and spleen and, with the T2-weighted fast spin-echo sequence, no differences were found for the spleen. Significant differences between both groups were seen for the liver with the T2-weighted fast spin-echo sequence. The SNR in the noncirrhotic liver group was 57.4 % lower than the SNR in the cirrhotic liver group. With the T2^*-weighted gradient-echo sequence, the SNRs of the liver and spleen in the noncirrhotic liver group, compared with the cirrhotic liver group, were 126.8 % and 45.6 % less, respectively. The effect of Endorem on the liver in patients with Child C-stage liver cirrhosis was 32.1 % less than in patients with Child B-stage liver cirrhosis. Likewise, the Endorem effect on the spleen was 27.1 % less in patients with Child C-stage compared with Child B-stage liver cirrhosis. Hepatic and splenic uptake of Endorem is significantly decreased in patients with liver cirrhosis. Received: 3 February 1999; Revision received: 21 October 1999; Accepted: 27 October 1999     

Angiomyolipoma of the liver: ferumoxides-enhanced MR imaging

We report a case of angiomyolipoma of the liver with emphasis on the appearance at MRI after administration of ferumoxides. Post-contrast T1- and T2-weighted images showed a frank decrease of signal intensity in a rim on the margin of the tumor. This unusual finding was related to the presence of an increased number of CD68-positive histiocytic cells in the periphery of the lesion and in the adjacent liver parenchyma. Received: 13 September 1999; Revised: 2 February 2000; Accepted: 3 February 2000     

Detection of liver metastases with pulse inversion harmonic imaging: preliminary results

The aim of this study is to evaluate capability of contrast enhanced ultrasonography (US) using pulse inversion harmonic imaging (PIHI) to detect liver metastases in comparison to fundamental B-mode ultrasound and spiral CT. Thirty-six consecutive patients with known malignancies and sonographically proved or suspicious liver metastases have been examined with fundamental B-mode US, with PIHI 2', 4' and 6' after Levovist injection and with four phase spiral-CT. Presence, conspicuity and number of lesions have been evaluated comparing PIHI with fundamental B-mode US and spiral-CT. A strong grey-scale enhancement of the liver parenchyma has been observed 2' and 4' after Levovist injection. The optimum parenchymal enhancement and contrast difference between liver and metastases was observed during the 2' measurements. PIHI revealed more lesions than fundamental B-mode US in 56 % of patients, while in 39 % and in 5 % revealed respectively the same number and fewer lesions. PIHI and spiral-CT were in agreement in 67 % of patients, while in 22 % and 11 % PIHI revealed respectively more and fewer lesions. PIHI accurancy presents restrictions in anterior superficial and in deep liver areas, whereas it may be superior to spiral-CT in studying sub-diaphragmatic liver regions.     

Clinical use of Levovist, an ultrasound contrast agent, in the imaging of liver transplantation: assessment of the pre- and post-transplant patient

Colour Doppler US is well established for imaging of hepatic vessels in the assessment of pre- and post-liver transplant patients. Unfortunately, a full colour Doppler US examination of the portal or hepatic venous and hepatic arterial systems is frequently precluded by technical factors. Ultrasound contrast agents are useful in enhancing vascular Doppler signal and play an important role in liver transplantation assessment. A series of patients with vascular problems illustrates the role of US contrast in the pre-transplant candidate, where portal vein patency and direction of flow is assessed, presence of portal vein thrombus is confirmed and cavernous transformation demonstrated. Occlusion of hepatic veins in Budd-Chiari syndrome is confidently confirmed. Following liver transplantation, US contrast allows a comprehensive assessment of hepatic artery thrombosis, hepatic artery stenosis and pseudoaneurysm formation. The need for further imaging is reduced or confidently deferred in many instances. Ultrasound contrast agents play an important role in the liver transplant candidate. Received: 15 April 1999; Revised: 21 June 1999; Accepted: 22 June 1999     

Therapeutic effect of transcatheter arterial chemoembolization on hepatocellular carcinoma: evaluation with contrast-enhanced harmonic power Doppler ultrasound

The aim of this study was to investigate the usefulness of contrast-enhanced harmonic power Doppler ultrasound (US) for the detection of residual viable hepatocellular carcinoma (HCC) after treatment with transcatheter arterial chemoembolization (TACE). Forty-seven patients with 68 HCC lesions 1.8–9.5 cm in diameter (mean ± SD 4.3 ± 1.7 cm) underwent contrast-enhanced power Doppler US, in the harmonic mode, before and after treatment with TACE. Unenhanced spiral CT and contrast-enhanced dynamic MR imaging were also performed to help establish the outcome of therapy. Before treatment, intratumoral blood flow signals were detected at contrast-enhanced harmonic power Doppler US in 65 (95 %) of 68 lesions. After TACE, flow signals were no longer detectable in 22 of these 65 lesions, which showed complete response at spiral CT and dynamic MR imaging. In 38 (88 %) of the 43 lesions with partial response, intratumoral flow signals were still identified at contrast-enhanced harmonic power Doppler US. Twenty-eight of these 38 lesions underwent additional treatment with percutaneous ethanol injection (PEI) using contrast-enhanced harmonic power Doppler US guidance. Complete response was seen after PEI in 23 of 28 lesions. Contrast-enhanced harmonic power Doppler US proved useful for assessing the therapeutic effect of TACE on HCC and for guiding additional treatment with PEI in cases of partial response. Received: 25 January 2000; Revised: 21 April 2000; Accepted: 25 April 2000     

Focal liver lesions: Doppler ultrasound

Echo patterns of focal liver lesions as well as other morphological criteria do not suffice for differential diagnosis. In an attempt to increase the specificity of ultrasound of focal liver lesions, several years of Doppler-flow information was evaluated. Recent advances in ultrasound technology (power Doppler imaging, second harmonic imaging) as well as commercial availability of an intravenous signal enhancer (contrast agent) have additionally improved results of this technique. Received: 9 January 1998; Revision received: 18 May 1998; Accepted: 14 July 1998     

Benign and malignant hepatocellular tumors: evaluation of tumoral enhancement after mangafodipir trisodium injection on MR imaging

The aim of this work was to study the ability of mangafodipir trisodium (Mn-DPDP)-enhanced MR imaging in differentiating malignant from benign hepatocellular tumors. Eleven patients with pathologically proved hepatocellular carcinomas, six with focal nodular hyperplasias, and one with a single hepatocellular adenoma were examined by spin-echo and gradient-echo T1-weighted sequences before, 1 h after, and 24 h after intravenous injection of Mn-DPDP (5 μmol/kg). Quantitative analysis including enhancement and lesion-to-liver contrast-to-noise ratio, and qualitative analysis including the presence of a central area and a capsule were done on pre- and post-Mn-DPDP-enhanced images. Enhancement was observed in all the tumors with significant improvement (p < 0.05) in contrast-to-noise ratio 1 h after, and 24 h after intravenous injection of Mn-DPDP. There were no significant differences in the mean enhancement and the mean contrast-to-noise ratio (CNR) between benign and malignant tumors. No enhancement was seen within internal areas observed in 7 hepatocellular carcinomas, and in 5 focal nodular hyperplasias, and within capsules which were observed in 9 hepatocellular carcinomas. In our study, Mn-DPDP increased CNR of both benign and malignant tumors but did not enable differentiation between benign and malignant tumors of hepatocellular nature. Received: 7 October 1997; Revision received: 25 February 1998; Accepted: 10 July 1998     

Effect of superparamagnetic iron oxide on bone marrow

The goal of this study was to compare the effects of SPIO particles on the signal intensity of the bone marrow of the vertebra spine in patients with and without liver cirrhosis. Forty-eight patients with normal liver tissue and 56 patients with liver cirrhosis were examined before and after intravenous SPIO administration, using a 1.5-T system (Magnetom Vision, Siemens, Erlangen, Germany) with a semiflexible cp-array coil. Three different pulse sequences were applied: a T1-weighted gradient-echo sequence, a T2-weighted fast spin-echo sequence with spectral fat suppression and a T2^*-weighted gradient-echo sequence. The signal-to-noise ratio (SNR) of the liver, vertebra bone and paraspinal muscle were obtained. The SNR value change in each patient group and the SNR value difference between the two groups were evaluated. For assessment of statistical significance, Student's t-test with a level of p < 0.05 was applied. No significant differences in the SNR values of the liver and bone marrow between the two groups could be seen with any of the three sequences precontrast. Using the T1-weighted gradient-echo sequence in the noncirrhotic liver group, pre- and postcontrast comparisons of the SNR values of the liver and bone marrow indicated a decrease of approximately –44.3 % (p = 0.02) and increase of approximately 15.3 % (p = 0.04), respectively. No significant change was seen in the cirrhotic liver group. With the T2-weighted fast spin-echo sequence, a significant decrease of the SNR value of the liver and the bone marrow in both groups was seen. With the T2^*-weighted gradient-echo sequence, the signal intensity decrease of the normal liver tissue was approximately –65.6 % (p = 0.00), in cirrhotic liver tissue the decrease was –29.9 % (p = 0.02). The SNR values of the bone marrow showed a decrease of –27.8 % (p = 0.04) in the noncirrhotic liver group, whereas in the cirrhotic liver group it was only –11.3 % and statistically not significant. The effect of SPIO particles on the liver and bone marrow is significantly less in patients with liver cirrhosis. Received: 2 April 1999; Revised: 5 October 1999; Accepted: 2 February 2000     

Graft-dependent recurrence of hyperparathyroidism: imaging with frequency amplitude and encoded Doppler sonography

A 48-year-old woman underwent total parathyroidectomy with autotransplantation into the left forearm due to secondary hyperparathyroidism. Recurrence of hyperparathyroidism was observed 5 years later. B-mode high-resolution ultrasonography of the left forearm demonstrated an ill-defined hypoechoic lesion. Frequency- and amplitude-encoded Doppler sonography revealed marked hypervascularity, which was diagnostic for graft hyperplasia in association with the history of the patient. These findings were confirmed by scintigraphy and histological examination of the excised graft. Received: 22 November 1999; Revised: 8 February 1999; Accepted: 9 February 1999     

Characterization of hypoechoic focal hepatic lesions in patients with fatty liver: diagnostic performance and confidence of contrast-enhanced ultrasound

The objective of this study was to assess the diagnostic performance of contrast-enhanced ultrasound (CEUS) to characterize hypoechoic focal hepatic lesions (HFHL) in fatty liver (FL). A study group of 105 patients with FL and 105 HFHLs (52 malignant and 53 benign) underwent CEUS after SonoVue administration. Two blinded readers independently reviewed baseline ultrasound (US) and CEUS scans and classified each lesion as malignant or benign on a five-point scale of confidence, and recorded whether further imaging work-up was needed. Sensitivity, specificity, areas under the receiver operating characteristic (ROC) curve (A (z)), and interobserver agreement were calculated. We observed that the diagnostic confidence improved after reviewing CEUS scans for both readers (A (z)=0.706 and 0.999 and A (z)=0.665 and 0.990 at baseline US and CEUS, respectively; p<0.0001). Inter-reader agreement increased (weighted k=0.748 at baseline US vs. 0.882 at CEUS). For both readers, after CEUS, the occurrence of correctly characterized lesions increased (from 27/105 [27.5%] to 94/105 [89.5%], and from 19/105 [18.1%] to 93/105 [88.6%], respectively; p<0.0001) and the need for further imaging decreased (from 93/105 [88.6%] to 26/105 [24.8%], and from 96/105 [91.4%] to 40/105 [38.1%], respectively; p<0.0001). We conclude that CEUS improves the diagnostic performance of radiologists in the characterization of HFHLs in FL and reduces the need for further imaging work-up.     

Multifocal nodular fatty infiltration of the liver mimicking metastatic disease on CT: imaging findings and diagnosis using MR imaging

The aim of this study was to describe the MR appearance of multifocal nodular fatty infiltration of the liver (MNFIL) using T1-weighted in-phase (IP) and opposed-phase (OP) gradient-echo as well as T2-weighted turbo-spin-echo sequences with fat suppression (FSTSE) and without (HASTE). Magnetic resonance imaging examinations at 1.5 T using T1-weighted IP and OP-GRE with fast low angle shot (FLASH) technique, and T2-weighted FSTSE, T2-weighted HASTE of 137 patients undergoing evaluation for focal liver lesions were reviewed. Five patients were identified in whom CT indicated metastatic disease; however, no liver malignancy was finally proven. Diagnosis was confirmed by biopsy (n = 3), additional wedge resection (n = 1) or follow-up MRI 6–12 months later (n = 5). Regarding the identified five patients, the number of focal liver lesions was 2 (n = 2) and more than 20 (n = 3). The MR imaging characteristics were as follows: OP-image: markedly hypointense (n = 5); IP image: isointense (n = 2) or slightly hyperintense (n = 3); T2-weighted FSTSE-image: isointense (n = 5); T2-weighted HASTE image isointense (n = 1); slightly hyperintense (n = 4). On OP images all lesions were sharply demarcated and of almost spherical configuration (n = 5). Further evaluation by histology or follow-up MR imaging did not give evidence of malignancy in any case. Histology revealed fatty infiltration of the liver parenchyma in three patients. Magnetic resonance follow-up showed complete resolution in two patients and no change in three patients. Multifocal nodular fatty infiltration can simulate metastatic disease on both CT and MR imaging. The combination of in-phase (IP) and opposed-phase (OP) gradient-echo imaging can reliably differentiate MNFIL from metastatic disease. Received: 15 September 1999 Revised: 3 February 2000; Accepted: 7 February 2000     

Frequency of pancreatitis after endoscopic retrograde cholangiopancreatography with iopromid or iotrolan: a randomized trial

Blood isotone contrast media is considered to be less toxic to vascular and pancreatic duct endothelium than high-osmolar contrast media. In this study we assessed the impact of a low-osmolar contrast agent compared with a blood isotone product on pancreatic damage induced by endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic retrograde sphincterotomy (EST). In a prospective trial 42 consecutive ERCP/EST patients were randomized to receive either iopromid, a low-osmolar non-ionic contrast agent (770 mosmol/kg H₂O), or iotrolan, a blood-isotone non-ionic product (320 mosmol/kg H₂O). The endoscopies were performed by two experienced endoscopists. Forty patients were included in the study. Blood samples were collected before and 40 min, 2, 4, 6 and 24 h after the endoscopic procedure. Samples were analysed for pancreatic serum enzymes, acute-phase proteins and blood counts. A clinical pain score was investigated. Post-ERCP pancreatitis was diagnosed in 2 patients in the iopromid group and in 5 patients in the iotrolan group. There was no significant difference between groups in the time course of pancreatic serum enzymes, acute-phase proteins or in the pain score. Due to the small number of patients in this study, only stronger differences caused by the two contrast media could have led to statistically significant results. We did not observe statistically significant differences in comparing iotrolan and iopromid concerning ERCP/EST-induced pancreatic damage. Received: 26 February 1999; Revised: 14 May 1999; Accepted: 9 June 1999     

Dynamic magnetic resonance imaging in the assessment of chronic medical nephropathies with impaired renal function

We examined the value of dynamic magnetic resonance imaging (MRI) in chronic renal disease with renal insufficiency. In 33 consecutive patients (21 vascular nephropathy, 12 glomerular nephropathy) MRI was performed using a 1.5-T unit and a body coil, with SE T1-weighted (TR/TE = 600/19 ms) and dynamic TFFE T1-weighted sequences (TR/TE = 12/5 ms, flip angle = 25 °) after manual bolus injection (via a cubital vein) of 0.1 mmol/kg Gd-DTPA-BMA. Morphological evaluation was performed in unblinded fashion by three radiologists, evaluating renal size, cortical thickness, and corticomedullary differentiation. Functional analysis was performed by one reviewer. Time-signal intensity curves, peak intensity value (P), time to peak intensity (T), and the P/T ratio were obtained at the cortex, medulla, and pyelocaliceal system of each kidney. The relationship of these parameters to serum creatinine and with creatinine clearance was investigated. A good correlation between morphological features of the kidneys and serum creatinine values was found. Morphological findings could not distinguish between vascular and glomerular nephropathies. A statistically significant correlation (P <0.01) between cortical P, cortical P/T, medullary P, and serum creatinine and creatinine clearance was found. A significant correlation (P <0.01) was also found between cortical T, medullary P/T, T of the excretory system, and creatinine clearance. The cortical T value was significantly higher (P <0.01) in vascular nephropathy than in glomerular nephropathy. Thus in patients with chronic renal failure dynamic MRI shows both morphological and functional changes. Morphological changes are correlated with the degree of renal insufficiency and not with the type of nephropathy; the functional changes seem to differ in vascular from glomerular nephropathies. Received: 5 March 1999; Revised: 28 June 1999; Accepted: 9 August 1999