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Enhancement characteristics of liver metastases, hepatocellular carcinomas, and hemangiomas with Gd-EOB-DTPA: preliminary results with dynamic MR imaging

Abstract Our objective was to study Gd-EOB-DTPA for the characterization of focal liver lesions by means of dynamic MR imaging. A double-blind and randomized dose-ranging phase-2 clinical trial was performed in 31 patients (liver metastases n = 23, hepatocellular carcinoma n = 4, and hemangioma n = 4) at a field strength of 1.0 Tesla. Gd-EOB-DTPA (Schering AG, Berlin, Germany) was administered as an IV bolus (12.5, 25, or 50 μmol/kg body weight) with dynamic T1-weighted MRI during the distribution and cellular uptake of the contrast agent at multiple time points up to 45 min post contrast. Dynamic changes in tumor signal intensity, tumor–liver contrast, enhancement patterns, side effects, and adverse events were evaluated. Monitoring of vital signs revealed no significant changes during bolus injection of Gd-EOB-DTPA. Liver metastases demonstrated an inhomogeneous uptake of Gd-EOB-DTPA during the distribution phase with a washout effect on delayed images > 3 min and highest tumor–liver contrast 20 and 45 min post contrast. Hepatocellular carcinomas showed prolonged enhancement as compared with metastases and hemangiomas. Hemangiomas exhibited an early peripheral–nodular enhancement with subsequent partial or complete filling, persisting enhancement < 10 min following injection of Gd-EOB-DTPA, and delayed washout as compared with liver metastases. Initial clinical experience suggests that Gd-EOB-DTPA as a bolus injectable hepatobiliary MR contrast agent may offer useful features for the characterization of focal liver lesions.

IN-VITRO HIGH-RESOLUTION ULTRASONOGRAPHY OF BENIGN AND MALIGNANT LYMPH NODES. A SONOGRAPHIC-PATHOLOGIC CORRELATION

RATIONALE AND OBJECTIVES.The authors assess the value of combining high-resolution ultrasonography (HRUS) findings in a scoring scale for distinguishing malignant from reactive lymphadenopathy and explain the pathologic causes of altered nodal sonographic architecture. MATERIALS AND METHODS.Sixty-one nodes obtained from 32 consecutive patients were prospectively scanned with 7.5-MHz ultrasound probes in a waterbath. Three sonographic features— long-to-short axis ratio (L/S), hilar width, and cortical width—were graded on a 5-level scoring scale (0-4). Nodes scored 5≥ 3 were considered malignant and ≤ 2 benign. Subsequently, all nodes were microscctioned in a plane matching the sonograms, allowing direct sonographic-pathologic correlation. RESULTS.Eighty-two percent of nodes were correctly characterized using the above cut-off point (sensitivity: 87%, specificity: 74%). Eighty-three percent of nodes scored 4 were malignant and 95% scored 0 were benign. Eighty-two percent of nodes with L/S < 2, 81% with no hilus, and 70% with eccentric cortical widening were malignant, whereas 72% with L/S ≥ 2, 86% with a wide hilus, and 91% with a narrow cortex were benign. Sonographic-pathologic correlation showed that tumor infiltration results in rounded nodal shape, loss of hilar echogenicity and cortical widening, whereas reactive disease tends to preserve nodal architecture. CONCLUSION.Morphologic changes detectable using HRUS help distinguish benign from malignant lymph nodes.

Gadolinium-DTPA in rheumatoid arthritis and related diseases: first results with dynamic magnetic resonance imaging

Thirty-four joints (19 knees, 15 wrists) of 31 patients suffering from rheumatoid arthritis and related disorders were examined prior to and following intravenous administration of Gadolinium-DTPA (0.1 mmol/kg body weight). T1-weighted spin-echo sequences and the gradient-echo technique FLASH were applied. FLASH scanning was used for the registration of the time-dependent changes of signal intensity following Gd-DTPA. Synovial proliferations exhibited a rapid and marked increase of signal intensity whereas fatty tissue, bone marrow, muscle and synovial effusion demonstrated only minor changes, causing enhanced contrast between synovial pannus and joint effusion or other neighbouring structures. Within the synovial pannus, ratios (absolute signal increase) of 131.3±53.4% and 122.9±51.1% were found in T1-weighted spin-echo and in FLASH sequences respectively. The average signal increase gradient of pannus (108.2±70.6%/min) was significantly (p<0.001) different from muscle (13.4±7.8%/min), fatty tissue (10.2±8.4%/min), bone marrow (5.5±7.1%/min), and joint effusion (14.7±7.8%/min).

Magnetic resonance in cartilaginous lesions of the knee joint with three-dimensional gradient-echo imaging

Diagnosis of chondromalacia of the patellofemoral joint using three-dimensional gradient-echo sequences was investigated in 41 patients, with arthroscopic verification in 25 patients. In vitro examinations in human caderveric patellae were performed in order to determine optimal imaging parameters. FLASH (TR=40 ms, TE=10 ms, flip angle=30°) and FISP (TR=40 ms, TE=10 ms, flip angle=40°) were used in clinical studies. Advanced stages of chrondromalacia could be visualized with high sensitivity. The therapeutically relevant differentiation of major and minor degrees of chondromalacia seems to be possible. 30° FLASH-images in the axial plane proved to be the most efficacious technique for the diagnosis of chondromalacia.

Comparison of technetium 99m polyclonal human immunoglobulin and technetium 99m monoclonal antibodies for imaging chronic osteomyelitis. First clinical results.

The accuracy of technetium-99m human immunoglobulin (HIG) for the detection of chronic osteomyelitis (OM) was compared with white blood cell scintigraphy using99mTc-labelled monoclonal mouse antibodies (MAB). Seventeen patients suspected of having OM in 20 lesions went through three-phase skeletal scintigraphy, HIG scintigraphy and MAB scintigraphy. The final diagnosis was established by open surgery, histology and bacteriology. Chronic OM was proved in 14/20 lesions. Six of these 14 infections were located in peripheral areas without active bone marrow and 8/14 in central areas with active bone marrow. In peripheral OM, 5/6 with HIG and 6/6 with MAB were true positives. In the central skeleton all 8/8 infections appeared as cold lesions in the MAB study, which were defined as being false negative due to their non-specificity. Using HIG, 5/8 central infections were determined to be truly positive by showing photon-rich lesions. These 5 lesions were located in the hip region and in the pelvis, whereas 3 lesions of the spine were missed. There were no false-positive results in either studies. In conclusion, MAB was superior to HIG in peripheral OM concerning sensitivity, anatomical landmarks and differentiation of soft tissue versus bone infection. In central OM MAB detected all lesions accurately, but no differential diagnosis was possible due to the non-specificity of photon-low areas. In this respect HIG seems to be more specific due to the increased accumulation even in central infection sites.

Brain imaging: Reduced sensitivity of RARE-derived techniques to susceptibility effects

OBJECTIVE Our goal was to evaluate the decreased sensitivity of RARE-derived pulse sequences to susceptibility effects. MATERIALS AND METHODS A variety of RARE-derived T2-weighted fast SE echo (FSE) sequences with echo trains from 6 to 16 were compared with conventional SE (CSE) sequences by means of MRI in phantoms (iron oxides), volunteers (n = 10), and patients (n = 13) with old hemorrhagic brain lesions. All experiments were performed on a 1.5 T clinical MR system (Magnetom SP 4000; Siemens AG, Erlangen, Germany) with constant imaging parameters. Contrast-to-noise ratios (CNRs) of tubes doped with iron oxides at different concentrations and brain areas with physiological iron deposition (red nucleus, substantia nigra) were calculated for CSE and FSE pulse sequences. Areas of old brain hemorrhage were analyzed for lesion conspicuity by blinded analysis with CSE as an internal standard. RESULTS CNR of iron oxide tubes (TE 90 ms, CSE 45.0 +/- 3.5, FSE 16 echo trains 28.5 +/- 3.1; p < or = 0.01) and iron-containing brain areas decreased with increasing echo trains of FSE sequences. A significantly lower number of old hemorrhagic brain lesions was visible in patients scanned with FSE sequences (6 echo trains: n = 28; 16 echo trains; n = 26) than CSE (n = 40). CONCLUSION Our results demonstrate that the sensitivity of RARE-derived techniques to susceptibility effects is significantly decreased compared with CSE. CSE sequences or GE sequences should still be preferred in patients with a history of seizures or intracranial hemorrhage.

Popliteal pseudoaneurysm and arteriovenous shunt following arthroscopic meniscectomy: case report.

Arthroscopic procedures have a low complication rate regarding vascular injury. This report describes a pseudoaneurysm of the right popliteal artery with an arteriovenous shunt following arthroscopic resection of remnants of the posterior horn of the medial meniscus, a complication not previously reported.

Neue MR-Kontrastmittel in der LeberdiagnostikErste klinische Ergebnisse mit hepatobiliärem Eovist® (Gadolinium-EOB-DTPA) und RES-spezifischem Resovist® (SH U 555 A)

ZusammenfassungIn der vorliegenden Arbeit werden erste klinische Ergebnisse (66 Patienten) der für die Leberbildgebung entwickelten Kontrastmittel Resovist® und Eovist® vorgestellt. Es wurden Sicherheitsaspekte, Dosierungsfragen und die optimale Untersuchungstechnik am Beispiel fokaler Leberläsionen untersucht. Beide „leberspezifischen“ Kontrastmittel zeigten bei guter Verträglichkeit eine Verbesserung des Nachweises fokaler Leberläsionen. Die Untersuchung mit Resovist® kann bereits 10 min nach der Kontrastmittelinjektion erfolgen. Mit einer Dosis von 8 μmol Fe/kg Körpergewicht konnte eine ausreichender Tumor-Leber-Kontrast erzielt werden. Da Eovist® zusätzlich im Bolus injiziert werden kann, ergeben sich neben dem Nachweis fokaler Leberläsionen Möglichkeiten der Charakterisierung durch Analyse der Perfusionsmuster. Atemgehaltene T 1-gewichtete FLASH-Sequenzen waren sonstigen T 1-gewichteten Sequenzen ohne und mit Fettgesättigung überlegen.SummaryThe purpose of this work is to describe our initial clinical experience (in 66 patients) with Resovist and Eovist, two new liver-specific MR contrast agents. We focus our report on safety aspects, dose finding, and optimization of technical parameters. Both contrast agents were well tolerated and improved the detectability of focal liver lesions. With Resovist, postcontrast MRI may be started as early as 10 min following injection. The dose of 8 μmol Fe/kg bodyweight was sufficient to achieve diagnostic tumor-liver contrast levels. Since Eovist can also be administered as a bolus, dynamic enhance- ment patterns may be studied for tumor characterization as well. Breath-hold T 1-weighted FLASH images were superior to other T 1-weighted techniques with and without fat saturation.

Study of susceptibility-induced artefacts in GRASE with different echo train length

Abstract. The aim of this study was to evaluate the sensitivity of gradient-and-spin-echo (GRASE) sequences to susceptibility effects. GRASE sequences with 21 and 33 echoes per echo train were compared with a T2-weighted FSE sequence with an echo train length of 5 by means of MRI in phantoms, volunteers (n = 10), and patients (n = 19) with old hemorrhagic brain lesions. All experiments were performed on a 1.0-T clinical MR system (Impact Expert, Siemens AG, Erlangen, Germany) with constant imaging parameters. Contrast-to-noise ratios (CNRs) of tubes doped with iron oxides at different concentrations, of brain areas with physiological iron deposition (red nucleus, substantia nigra), and of areas of old brain hemorrhage were calculated for FSE and GRASE pulse sequences. Areas of old brain hemorrhage were also qualitatively analyzed for the degree of visible susceptibility effects by blinded reading. The CNR of iron oxide tubes and iron-containing brain areas decreased with increasing echo trains of GRASE sequences. The CNR of GRASE sequences decreased when compared with CNR of their FSE counterparts (GRASE 21 echo trains 23.8 ± 0.8, FSE 5 echo trains 26.7 ± 0.9; p≤ 0.01). Qualitative analysis confirmed these measurements. FSE with an ETL of 5 demonstrated significantly stronger susceptibility effects than their GRASE counterpart with an ETL of 21. The results demonstrate that GRASE sequences do not necessarily compensate for the reduced sensitivity of FSE to susceptibility effects. The complex signal behavior of GRASE makes conventional SE, gradient echo, or FSE sequences containing shorter echo trains preferable when patients with intracranial hemorrhage are clinically evaluated.

Die Wertigkeit der 3-Phasen-Spiral-CT und der Magnetresonanztomographie in der präoperativen Diagnostik des Pankreaskarzinoms

ZusammenfassungDas Ziel der vorliegenden Untersuchung an 28 Patienten war die Bestimmung der Wertigkeit der Spiralcomputertomographie (Spiral-CT) und der Magnetresonanztomographie (MRT) im präoperativen Staging des Pankreaskarzinoms. Dazu wurde vergleichend die Infiltration peripankreatischer arterieller und venöser Gefäßstrukturen analysiert. Die Befunde wurden mit dem Ergebnis der Laparotomie korreliert, der alle Patienten unabhängig von den Ergebnissen der Spiral-CT und der MRT unterzogen wurden. Zur präoperativen Bestimmung der lokalen Ausdehnung von Pankreaskarzinomen und damit der Operabilität sind sowohl die 3-Phasen-Spiral-CT und die MRT (± Gadolinium-DTPA) gleichermaßen geeignete Untersuchungsmethoden. Insbesondere können beide Untersuchungsverfahren die Infiltration benachbarter vaskulärer Strukturen präoperativ mit hoher Genauigkeit nachweisen und somit die Planung des operativen Vorgehens beeinflussen.SummaryThe purpose of this study was to assess the role of spiral computed tomography (SCT) and magnetic resonance imaging (MRI) in the preoperative work-up of patients with pancreatic carcinoma, regarding local resectability and vascular involvement. Methods and materials: A total of 28 patients (19 men and 9 women; mean age 58 years) with known or highly suspected carcinoma of the pancreas were included in this study. All patients prospectively underwent MRI (± gadolinium-DTPA) and SCT (3-phase examination) as preoperative diagnostic imaging studies, and laparotomy was carried out within 7 days, irrespective of the MRI or SCT findings. SCT and MR studies were reviewed independently by two radiologists, without knowing the results of the surgical exploration. Standardized image analysis was correlated with findings at laparatomy. Results: Laparotomy identified 10 patients to be suitable for surgical resection and 18 pancreatic carcinomas to be unresectable. In 17 of 18 non-resectable carcinomas MRI and SCT were able to obtain correct information about unresectability (sensitivity 94 %), in 7 (MRI), resp. 8 (SCT) carcinomas were correctly considered to be resectable (sensitivity 70 % for MRI and 80 % for SCT). The presence of vascular involvement was depicted by SCT with a sensitivity of 82–100 % and 62–100 % by MRI. The specificity varied between 85–100 % for SCT and 77–100 % for MRI. Conclusion: Both MRI and SCT are good techniques for the preoperative work-up of pancreatic carcinomas in order to obtain a correct assessment of local resectability.