N. Hidajat

D-GALACTOSE-BASED SIGNAL-ENHANCED COLOR DOPPLER SONOGRAPHY OF BREAST TUMORS AND TUMORLIKE LESIONS

RATIONALE AND OBJECTIVES This study sought to evaluate prospectively the diagnostic potential of unenhanced and enhanced color Doppler and power Doppler for the differentiation of tumors and tumorlike lesions of the breast. METHODS Ninety-two patients with 110 tumors or tumorlike lesions of the breast were investigated by unenhanced and enhanced color and power Doppler ultrasound. The sonomorphologic aspects of vascularization were analyzed. In addition, maximal systolic frequency shift, resistance, and pulsatility indices were determined. RESULTS In 15 (24%) of 63 primary carcinomas, 15 (68%) of 22 fibroadenomas, and all (100%) of 14 postoperative lesions, the sonomorphologic analysis for the differential diagnosis of breast tumors was improved after contrast enhancement in color Doppler mode. In comparing unenhanced color Doppler to power Doppler, the latter was found to be slightly superior (sensitivity, 60% vs. 67%; specificity, 39% vs. 45%, respectively); after enhancement, both modes were equivalent (sensitivity, 100% vs. 100%; specificity, 95% vs. 95%, respectively). Signal enhancement resulted in a significant improvement in sensitivity and specificity (P < 0.01). Typical signs of malignancy were irregular vessel calibers, serpiginous courses, penetration of the tumors margin, and irregular reticular vascularization. The quantitative parameters proved not to be helpful for the differential diagnosis of breast tumors. CONCLUSIONS By improved analysis of the vascularization pattern, d-galactose-enhanced color Doppler sonography was found to provide more reliable differential diagnostic information than unenhanced Doppler ultrasound in tumors and tumorlike lesions of the breast.

RADIATION EXPOSURE IN SPIRAL COMPUTED TOMOGRAPHY: DOSE DISTRIBUTION AND DOSE REDUCTION

RATIONALE AND OBJECTIVES The authors investigate the dose distribution of spiral and conventional computed tomography (CT) with film densitometry and to present a new method of evaluating the possibility of dose savings with spiral CT. METHODS Films were exposed in a cuboid polymethyl-methacrylate phantom in conventional and spiral scan technique. Axial density profiles were obtained by digitizing the films using a fluorescent light scanner. The ratio of the number of rotations in spiral CT to the number of slices in conventional CT was calculated. RESULTS In spiral CT with a pitch of 2, the densities in all points were lower than those in corresponding points in spiral CT with a pitch of 1 and in conventional CT with slice distance equal to slice thickness. A pitch of 1.5 in spiral CT led to a dose reduction of 14% to 30% compared with conventional CT. CONCLUSIONS Increasing the pitch in spiral CT leads to a reduction of both integral dose and absorbed doses within the examined body region. The reduction of the integral dose can be significant, especially in cases where slice overlapping is diagnostically advantageous.

Radiation Exposure to Patient and Staff in Hepatic Chemoembolization: Risk Estimation of Cancer and Deterministic Effects

The purpose of the study was to determine the risks of radiation-induced cancer and deterministic effects for the patient and staff in transarterial chemoembolization (TACE) of hepatocellular carcinoma (HCC). Sixty-five patients with HCC underwent the first cycle of TACE. Thermoluminescence dosemeters and conversion factors were used to measure surface doses and to calculate organ doses and effective dose. For the patient, the risk of fatal cancer and severe genetic defect was in the magnitude of 10−4 and 10−5, respectively. Five patients showed surface doses over the first lumbar vertebra exceeding 2000 mSv and 45 patients showed doses over the spine or the liver region above 500 mSv. The risk of fatal cancer and severe genetic defect for the radiologist and assistant was in the magnitude of 10−7 to 10−8. They could exceed the threshold for lens opacity in the case of more than 490 and 1613 TACE yearly for a period of many years, respectively. Radiation dose could lead to local transient erythema and/or local depression of hematopoiesis in many patients after TACE. For the radiologist and assistant, risk of fatal cancer and genetic defect and lens opacity might arise when they perform interventions such as TACE intensively.

Imaging and Radiological Interventions of Portal Vein Thrombosis

Portal vein thrombosis (PVT) is diagnosed by imaging methods. Once diagnosed by means of ultrasound, Doppler ultrasound can be performed to distinguish between a benign and malignant thrombus. If further information is required, magnetic resonance angiography or contrast‐enhanced computed tomography is the next step, and if these tests are unsatisfactory, digital subtraction angiography should be performed. Many papers have been published dealing with alternative methods of treating PVT, but the material is fairly heterogeneous. In symptomatic non‐cavernomatous PVT, recanalization using local methods is recommended by many authors. Implantation of transjugular intrahepatic portosystemic shunt is helpful in cirrhotic patients with non‐cavernomatous PVT in reducing portal pressure and in diminishing the risk of re‐thrombosis. In non‐cirrhotic patients with recent PVT, some authors recommend anticoagulation alone. In chronic thrombotic occlusion of the portal vein, local measures may be implemented if refractory symptoms of portal hypertension are evident.

Transjugular intrahepatic portosystemic shunt: Experiences at a liver transplantation center

Objective: Transjugular intrahepatic portosystemic shunt (TIPS) placement is an established therapy for portal hypertension that leads to variceal bleeding or refractory ascites. We present experiences of the role of TIPS at a liver transplantation center. Material and Methods: One hundred and ten patients were referred to the Radiological Department for TIPS placement. One of the 110 patients had recurrent cirrhosis after liver transplantation with refractory ascites. Function of the TIPS was controlled with Doppler US at 1 day, 1 week, 4 weeks and 4 months after TIPS placement and subsequently every 3 months. Shunt insufficiency was supposed when the blood flow velocity within the stent tract was under 50 cm/s and was an indication for TIPS revision. Results: TIPS was placed in 101 patients. After TIPS placement, 10 patients underwent liver transplantation. While waiting for the new liver, none of them developed variceal rebleeding, ascites or other complications of portal hypertension. Two of the 101 patients had episodes of rebleeding. The frequency of patients undergoing TIPS revision within the first year after TIPS placement was 67.5%, within the second year 38.0% and within the third year 24.4%. The revisions led to sufficient reduction of the portosystemic pressure gradient. Conclusion: In some liver transplant candidates, TIPS can be useful in minimizing the risk of complications of portal hypertension during the waiting time for a liver transplantation. TIPS can be monitored by Doppler US and revised if occlusion occurs.

Vascularization of reactively enlarged lymph nodes analyzed by color duplex sonography

PURPOSE This study involved a prospective evaluation of the reliability of sonography, and especially duplex sonography, in confirmation of the benign nature of enlarged cervical lymph nodes. PATIENTS AND METHODS In 53 untreated patients with enlarged cervical lymph nodes, B-mode, plain, and d-galactose-enhanced color duplex sonography were performed. The B-mode sonomorphology was analyzed for the structure of vascularization. Quantitative parameters such as maximum flow velocity, pulsatility index, and resistive index were also assessed. The benignity of the lymph nodes was confirmed by microscopic analysis. RESULTS The B-mode showed 20 homogeneous lymph nodes, 23 with a central echogenoic line covering less than one third, and 10 with a distinct hilus sign extending to more than one third of the lymph node diameter. Microscopically, the least fibrotic or chronic inflammatory changes in the parenchyma were observed in the homogeneous lymph nodes, whereas those with central echogeneoity had fibrotic and lipoid hilus changes. Histologically, all lymph nodes had normal afferent and efferent hilus vessels. In 37 lymph nodes, the vessel structure could be reliably visualized by both plain and enhanced color duplex sonography, whereas in 16 it could only be demonstrated after the use of signal enhancement. Nine of 53 lymph nodes had Solbiati-(L/T-) indices below 2, which were suggestive of malignancy. Quantitative flow parameters did not provide useful information. CONCLUSION Color duplex analysis of enlarged lymph nodes is a useful method for assessment of benignity, especially after application of a signal-enhancing agent.

Placement of transjugular intrahepatic portosystemic shunt via the left hepatic vein under sonographic guidance in a patient with right hemihepatectomy.

In a patient with refractory ascites after right hemihepatectomy TIPS was created between the left hepatic vein and the left portal vein via a transjugular approach. The puncture was guided only by sonography from the epigastrium. Portosystemic pressure gradient was reduced from 28 to 7 mm Hg and ascites disappeared. This case shows that TIPS can be created with technical and clinical success after right hemihepatectomy as left hepatic vein to left portal vein shunt under sonographic guidance.

Quantitative Computertomographie der Knochenmineraldichte des Unterkiefers Darstellung der topographischen Verteilung der Knochenmineraldichte bei automatisierter Segmentierung der Kieferstrukturen

ZusammenfassungFragestellung. Verifizierung einer neuen Technik zur Bestimmung der Knochenmineraldichte bei automatisierter Segmentierung der Kieferstrukturen. Farblich differenzierte Darstellung der topographischen Verteilung der Knochenmineraldichte der Spongiosa. Methoden. Für 20 Patienten wurden Dental-CT-Untersuchungen des Unterkiefers in Axialschichten durchgeführt. Die Bildpunkte der Kortikalis und Spongiosa wurden auf Höhe der Foramina mentalia über eine Schwellenwerteinstellung automatisiert segmentiert. Die Segmente wurden in implantologisch interessierende Regionen unterteilt. Für jede Region wurde die Knochenmineraldichte mittels quantitativer Computertomographie gemessen. Die Spongiosa von 20 Unterkiefern wurde durch 3 Schwellenwertintervalle segmentiert, um die topographische Verteilung der Knochenmineraldichte darzustellen. Ergebnisse. Bei 20 Unterkieferknochen konnten Kortikalis und Spongiosa automatisiert segmentiert werden. Die Knochenmineraldichte konnte für jede Region gemessen werden. Die Messwerte waren mit denen anderer Techniken vergleichbar. Drei Schwellenwertintervalle wurden für 20 Unterkiefer im Bereich der Spongiosa segmentiert, um die topographische Verteilung der Knochenmineraldichte darzustellen. Schlussfolgerungen. Durch die Darstellung der topographischen Verteilung der Knochenmineraldichte können Bereiche mit geringer Knochendichte erkannt werden. Subjektive Einschätzungen von Seiten des Untersuchers werden hierdurch eliminiert.AbstractPurpose. Confirmation of a new technique for evaluating bone mineral density (BMD). Colored coded imaging of topographical distribution of bone mineral density in the spongy substance. Method. For 20 patients, dental CT examinations of the mandible were made in axial slices. Spongy substance and cortical bone pixels were automatically segmented at foramina mentalia level by means of threshold fixation. The segments were separated in areas relevant to implantology. For each region, BMD was measured by means of quantitative computed tomography (QCT). Spongiose substance of 20 mandibles was segmented by using three treshold intervals to image topographical BMD distribution. Results. Cortical bone and spongy substance could be automatically segmented for 20 mandibles. BMD could be measured in each region. The results were comparable with those of other techniques. Three threshold intervals were segmented for 20 mandibles in the spongy substance to depict topographical BMD distribution. Conclusions. Areas of low BMD can be detected by imaging topographical BMD distribution. This way, subjective rating by the examiner is eliminated.

Wertigkeit der signalverstärkten farbkodierten Duplexsonographie in der Beurteilung von reaktiv vergrößerten Lymphknoten

ZusammenfassungZiel: In einer prospektiven Studie wurden reaktiv vergrößerte Lymphknoten hinsichtlich ihrer Sonomorphologie und der Vaskularisation mittels signalverstärkter farbkodierter Duplexsonographie untersucht. Methodik: 40 Patienten mit reaktiv vergrößerten Lymphknoten wurden mittels nativer und signalverstärkter farbkodierter Duplexsonographie untersucht. Die Lymphknoten wurden qualitativ in drei morphologische Gruppen differenziert: 1. homogenes Parenchym, 2. zentrale echogene Linie und 3. echogener „Hilus-Reflex”. In einer quantitativen Analyse wurden die maximale Flußrate sowie die Pulsatilitäts- und Widerstandsindizes bestimmt. Die qualitativen und quantitativen Befunde wurden mit der Histologie verglichen. Ergebnisse: 15 Lymphknoten (37,5%) stellten sich homogen dar. 17 Lymphknoten (42,5%) zeigten eine zentrale echogene Linie. Bei 8 Lymphknoten (20%) konnte ein zentraler hilärer Reflex nachgewiesen werden. Histologisch war der sonographischen Veränderung des Lymphknotenhilus eine Fibrose zuzuordnen. Die Vaskularisation der reaktiv vergrößerten Lymphknoten konnte bei 32,5% (13) erst nach Levovistgabe beurteilt werden. Die Flußgeschwindigkeit und Spektraldoppelindices zeigten für reaktiv vergrößerte Lymphknoten keinen spezifischen Unterschied. Schlußfolgerungen: Reaktiv vergrößerte Lymphknoten zeigen eine typische Sonomorphologie. Die Applikation von Levovist ermöglicht die Darstellung eines typischen Vaskularisationsmusters von reaktiv vergrößerten Lymphknoten.SummaryPurpose: This prospective study was performed to investigate characteristic sonomorphological features and vascularity of reactively enlarged lymph nodes. Method: We examined 40 patients with enlarged lymph nodes of the neck by Doppler sonography before and after administration of an ultrasound signal-enhancing agent. Peak flow velocity, pulsatility- and resistant indices were assessed. Lymph nodes were sonomorphologically classified into three groups: homogeneous parenchyma (1), a centrally located echogenoic line (2) and an echogenoic ”hilus reflex” (3). The quantitative and qualitative criteria were compared to histological findings. Results: A total of 15 lymph nodes appeared homogeneous. A centrally located echogenoic line was found in 17 (42.5%) nodes and echogenoic ”hilus reflex” in 8 (20%). These sonomorphological patterns correlate to hilus fibrosis in the histological specimen. In 32.5% (13) of the nodes the analysis of vascularity was possible only after application of the galactose-based ultrasound signal enhancer. Quantitative analysis did not result in specific new aspects. Conclusions: Reactive lymph nodes show typical sonomorphological features. Administration of an ultrasound enhancer allows assessment of a characteristic nodal vascualrity.

Intraluminal brachytherapy of de novo TIPS: a prospective randomized double-blind study.

OBJECTIVE The aim of this prospective double-blind and randomized study was to assess whether intraluminal brachytherapy of de novo transjugular intrahepatic portosystemic shunts (TIPS) can prevent significant shunt stenosis. SUBJECTS AND METHODS Forty patients with portal hypertension due to liver cirrhosis were enrolled. In the irradiation group of 20 patients, the gamma radiation source, iridium-192, was introduced into the shunt within a special balloon catheter that allows the radionuclide to be centered within the shunt. A dose of 14 Gy in the shunt wall at a depth of 2 mm should be achieved. In the control group of 20 patients, a dummy source was used. Doppler sonography was performed immediately, 1 day, 1 week, 4 weeks, and 3 months after TIPS placement and then at an interval of 3 months during the first year. The primary end point of the study was the percentage of patients who developed significant shunt stenosis, defined as a reduction of maximum flow velocity below 50 cm/sec in the proximal part of the shunt 1 cm from the entry of the stent into the punctured portal vein branch. Fishers exact test was used. RESULTS The TIPS procedure was technically successful in all patients. Seventeen patients in the irradiation group and 15 patients in the control group were followed up. Five patients (29.4%) in the irradiation group and 10 (66.7%) in the control group developed significant shunt stenosis during the first year after TIPS placement (p = 0.0392). The time until such stenosis occurred did not differ significantly between the two groups. CONCLUSION Our results suggest that brachytherapy can be useful in reducing the incidence of TIPS stenosis. A larger study with histopathologic analysis may be needed to confirm these findings.