Benedikt V. Czermak

Trace of diffusion tensor differentiates the Parkinson variant of multiple system atrophy and Parkinson's disease.

We have recently shown that diffusion-weighted magnetic resonance (MR) imaging (DWI) discriminates patients with the Parkinson variant of multiple system atrophy (MSA-P) from those with Parkinsons disease (PD) by regional apparent diffusion coefficients (rADC) in the putamen. Because rADCs measured in one direction may underestimate diffusion-related pathologic processes, we investigated the diffusivity in different brain areas by trace of diffusion tensor (Trace(D)) in a new cohort of patients with MSA-P and PD. We studied 11 MSA-P, 17 PD patients, and 10 healthy volunteers matched for age and disease duration. Regional ADCs in three orthogonal directions and Trace(D) values were determined in selected brain regions including the basal ganglia, gray matter, white matter, substantia nigra, and pons. MSA-P patients had significantly higher putaminal and pallidal rTrace(D) values as well as rADCs in y- and z-direction than both PD patients and healthy volunteers. Moreover, putaminal Trace(D) discriminated completely MSA-P from both PD and healthy volunteers. The rADCs in the y- and z-direction provided a complete or near complete separation. In conclusion, our study confirms the results of previous studies of our group that patients with MSA-P show an increased putaminal diffusivity due to neuronal loss and gliosis. Because rADCs in one direction are dependent on the slice orientation relative to the directions of fiber tracts, Trace(D) imaging appears to be more accurate in the separation of MSA-P from PD.

Echinococcosis of the liver

Echinococcosis, also known as hydatid disease, is an infection of larval stage animal tapeworm, Echinococcus. The larvae reside in the liver and lungs, producing multiloculated fluid-filled cysts. Imaging findings of Echinococcosis caused by E. granulosus are single, unilocular cyst or multiseptated cysts, showing “wheel-like”, “rosette-like” or “honeycomb-like” appearances. There may be “snow-flakes” sign, reflecting free floating protoscoleces (hydatid-sand) within the cyst cavity. Degenerating cysts show wavy or serpentine bands or floating membranes representing detached or ruptured membranes. Degenerated cysts show heterogeneous, solid-looking pseudotumor that may show “ball of wool sign”. Dead cysts show calcified cyst wall. Echinococcosis caused by E. multilocularis produces multilocular alveolar cysts with exogeneous proliferation, progressively invading the liver parenchyma and other tissues of the body. Imaging findings are ill-defined infiltrating lesions of the liver parenchyma, consisting of multiple small clustered cystic and solid components. On sonography, lesions are heterogeneous with indistinct margins, showing “hailstorm appearance” or “vesicular or alveolar appearance”. CT and MR imaging displays multiple, irregular, ill-defined lesions. Multiple small round cysts with solid components are frequent. Large lesions show “geographical map” appearance. Calcifications are very frequent, appearing as peripheral calcification or punctuate scattered calcific foci. Invasion into the bile ducts, portal vein or hepatic vein may occur. Direct spread of infected tissue may result in cysts in the peritoneal cavity, kidneys, adrenal gland or bones.

Type a Dissection following Endovascular Thoracic Aortic Stent-Graft Repair:

Purpose: To describe our experience with endovascular stent-graft repairs in the thoracic aorta focusing on the secondary complication of type A dissection. Methods: Between January 1996 and April 2004, 73 patients were treated for traumatic thoracic aortic rupture (n=15), type B dissection (n=22), or atherosclerotic descending thoracic aortic aneurysms (TAA, n=36). A retrospective review of the records found 5 (6.8%) patients (3 men; median age 64 years, range 43–87) who experienced a type A dissection at a median 20 days (range 2–124) after thoracic stent-graft repair for 3 type B dissections, 1 TAA, and a late type I endoleak that appeared 28 months after initial stent-graft repair of a traumatic dissection. Results: In 3 patients (2 dissections, 1 endoleak), a tear in the aortic wall at the proximal stent-graft was responsible for a retrograde type A dissection. Underlying disease was the cause of the type A dissection in the 2 other patients (1 dissection, 1 TAA) and was unrelated to the stent-grafts. Three patients underwent open surgery at 3, 26, and 124 days after stent-graft placement; 2 procedures were successful, but the third patient died 3 months later due to multiorgan failure. Two type A dissections were untreated: one patient died from cardiac tamponade 14 days after successful stent-graft exclusion of the type I endoleak; the other patient refused further treatment and survived. The procedure-related mortality following acute retrograde type A dissection was 40%. Conclusions: Endovascular stent-graft repair of the thoracic aorta is associated with lower morbidity and mortality rates than surgical repair, although potentially lethal complications, acute or delayed, may occur.

Serial CT Volume Measurements after Endovascular Aortic Aneurysm Repair

Purpose: To evaluate the efficacy of transluminal stent-graft placement in aortic aneurysms using postoperative enhanced spiral computed tomographic (CT) volumetric measurements of the aneurysm sac, the intra-aneurysmal vascular channel (IAVC), the thrombus, and the stent-graft. Methods: Among 53 patients (45 men; mean age 74 years, range 59–85) who underwent elective endovascular aortic aneurysm repair, 37 patients with 27 abdominal and 10 thoracic aortic aneurysms completed at least a 6-month follow-up that included computerized CT volumetric analysis prior to discharge and at 3, 6, 12, 24, and 36 months. A variety of bifurcated (n = 23) and tube (n = 14) stent-grafts were observed for signs of endoleak and aneurysm enlargement. Results: Mean follow-up was 16 months (range 6–48). Total aneurysm volumes and thrombus volumes decreased, whereas IAVC and stent-graft volumes increased over time. Between the postoperative and 12-month imaging studies, reductions in total aneurysm (p = 0.011) and thrombus (p < 0.001) volumes were significant. No statistically significant difference in volume changes for the aneurysm sac (p = 0.555) or the thrombus (p = 0.920) was found when comparing the 24 patients without primary leak to the 12 with primary type-II leak. In all 5 cases with secondary leak, the volume of the aneurysm sac increased after initial shrinkage. Conclusions: Postoperative CT volumetric analysis is an effective tool for evaluating the outcome of endovascular aortic aneurysm repair. Thrombus volume measurements are more accurate than total aneurysm volumes. In patients in whom contrast agents are contraindicated, volume measurements can also be obtained without the use of contrast.

Dialysis-Related Amyloidosis Revisited

OBJECTIVE Dialysis-related amyloidosis occurs secondarily to the deposition of beta(2)-microglobulin. Dialysis-related amyloidosis predominantly involves the osteoarticular system and is clinically manifested by erosive and destructive osteoarthropathies, destructive spondyloarthropathy, and carpal tunnel syndrome. This article illustrates the radiographic, sonographic, CT, and MRI findings of dialysis-related amyloid arthropathies. CONCLUSION Dialysis-related amyloidosis is characterized by various imaging appearances. In evaluating amyloidosis, MRI provides considerably more information than that obtained from conventional radiographic, CT, and sonographic studies.

Frameless Stereotactic Cannulation Of The Foramen Ovale For Ablative Treatment Of Trigeminal Neuralgia

OBJECTIVE: Ablative neurosurgical treatment of trigeminal neuralgia, including percutaneous radiofrequency thermocoagulation, requires cannulation of the foramen ovale. To maximize patient security and cannulation success, a frameless stereotactic system was evaluated in a phantom study, a cadaveric study, and a preliminary clinical trial. METHODS: Frameless stereotaxy using an optical navigation system, an aiming device, and a noninvasive vacuum mouthpiece-based registration and patient fixation technique was used for the targeting of a test body based on 1-, 3-, and 5-mm axial computed tomographic slices and of the foramen ovale in three cadavers and 15 patients based on 3-mm axial computed tomographic slices. RESULTS: The mean normal (x/y) localization accuracy/standard deviation (n = 360) was 1.31/0.67 mm (1-mm slices), 1.38/0.65 mm (3-mm slices), and 1.84/0.96 mm (5-mm slices). Significantly better results were achieved with 1- and 3-mm slices when compared with 5-mm slices (P < 0.001). The foramen ovale (3 × 6 mm) was successfully cannulated at the first attempt in all cadavers and patients, which indicates clinical localization accuracies better than 1.5 mm in the anteroposterior and 3 mm in the medial-lateral directions. CONCLUSION: Based on the noninvasive Vogele-Bale-Hohner vacuum mouthpiece, there is no need for invasive head clamp fixation. Imaging, real laboratory simulation, and the actual surgical intervention can be separated in time and location. The presented data suggest that frameless stereotaxy is a predictable and reproducible procedure, which may enhance patient security and cannulation success independent of the surgeon’s experience.

Serial CT Volume and Thrombus Length Measurements after Endovascular Repair of Stanford Type B Aortic Dissection

Purpose: To evaluate the outcome of stent-graft placement in Stanford type B aortic dissection using contrast-enhanced spiral computed tomographic (CT) measurements of true and false lumen volumes and thrombus length. Methods: Among 18 consecutive patients (13 men; mean age 60 years, range 44–79) who underwent endovascular repair of Stanford type B dissection, 12 completed at least a 12-month follow-up, which included CT measurements of true and false lumen volumes and thrombus lengths prior to discharge and at 6 and 12 months postimplantation. Volumes were assessed in 3 different aortic segments (A1, A2, A3) extending from the proximal attachment site of the prosthesis to the aortic bifurcation. In addition, thrombus length was measured to evaluate the influence of clot formation on outcome of the false lumen volume. Results: Mean follow-up was 27 months (range 12–60). Within 12 months, mean true lumen volumes showed statistically significant increases in the A1 (p<0.001) and A2 (p=0.003) segments; false lumen volumes showed a significant decrease in the A1 segment (p=0.002) but an insignificant increase in the A2 segment. No substantial volume changes were observed in the A3 segment. Extension of clot formation in the false lumen varied among patients and over time. Length of stent-grafts, percentage of stented dissection length, or visceral arteries originating from the false lumen did not significantly influence thrombus development, nor did these parameters or thrombus formation distal to the prosthesis have a relationship to false lumen volumes. Conclusions: Volumetric analysis after endovascular repair of Stanford type B dissection shows optimal technical outcome in the stented segment, whereas the false lumen in the segment immediately adjacent to the stent-graft seems to be a vulnerable area. Extension of clot formation beyond the endograft seems to be no reliable predictor of outcome.

Emergency endovascular treatment of traumatic aortic arch rupture with multiple arch vessel involvement.

Purpose: To report successful endovascular stent-graft placement for emergency treatment of a complex traumatic injury involving the aortic arch and multiple arch vessels. Case Report: An 81-year-old man underwent stent-graft placement for a complex traumatic vascular injury. Computed tomography on admission documented a dissection along the course of the aortic arch, intramural hematoma along the ascending aorta, dissection of the innominate artery, and a right subclavian artery pseudoaneurysm. The dissection of the aortic arch and the pseudoaneurysm of the right subclavian artery were treated immediately, the dissection of the innominate artery 7 days later. The patient did not develop any complications. Follow-up studies performed prior to discharge and at 6 and 12 months after the interventions showed successful repair of the complex vascular injuries. Conclusions: Traumatic injury of the aortic arch with multiple arch vessel involvement can be treated effectively by means of stent-graft placement.

Endoluminale Therapie der akuten und chronischen Dissektion Stanford Typ B

Ziel dieses Fortbildungsposters ist es, die Erfahrung eines „Single Centers“ in der endoluminalen Therapie der Aortendissektion Stanford Typ B in Zusammenschau mit der vorliegenden Literatur zu prasentieren. Seit 1996 wurden insgesamt 49 Patienten mit einer akuten (n=39)oder chronischen (n=10) Dissektion Stanford Typ B mit diesem neuen Therapieverfahren behandelt, die mittlere Beobachtungszeit betragt 36 Monate (0–103 Monate). Es werden prainterventionelle Abklarung, Indikationen und Kontraindikationen, technische Uberlegungen, intraoperative Komplikationen mit Vermeidungsstrategien, postinterventionelles Imaging, postinterventionelle Komplikationen, Strategien zur Behandlung von postinterventionellen Komplikationen, Erfahrungen mit verschiedenen Stent-Graft Designs, Volumensveranderungen des wahren und falschen Lumens im Kurz und Langzeitverlauf, Thrombosierung des falschen Lumens im Kurz und Langzeitverlauf und Mortalitat bzw. Morbiditat im Kurz und Langzeitverlauf prasentiert und diskutiert. Lernziele: Erlernen der Indikationen und Kontraindikationen fur die endoluminalen Therapie der Aortendissektion Stanford Typ B Erlernen der Komplikationen im Kurz und Langzeitverlauf nach der endoluminalen Therapie der Aortendissektion Stanford Typ B Imaging nach der endoluminalen Therapie der Aortendissektion Stanford Typ B Korrespondierender Autor: Czermak BV Universitatsklinik Innsbruck, Radiologie, Anichstrasse 35, 6020, Innsbruck E-Mail: benedikt.czermak@i-med.ac.at