Christoph Rehnitz

CT-guided radiofrequency ablation of osteoid osteoma and osteoblastoma: Clinical success and long-term follow up in 77 patients

The purpose of this study was to retrospectively evaluate long-term success of CT-guided radiofrequency ablation (RFA) in patients with osteoid osteoma (OO) and osteoblastoma (OB) including tumors in critical locations. Eighty-one CT-guided RFA procedures were performed in 77 patients with OO (65 patients) and OB (12) including 6 spinal and 15 intra/periarticular tumors. Procedural techniques included multiple needle positions, three-dimensional access planning, as well as, thermal protection techniques. Long-term success was assessed using a questionnaire including, among others, several VAS (visual analogue scale) scores. All patients completed 3-6 months follow-up, overall response to the questionnaire was 64/77 (83.1%). Primary success rate was 74/77 (96.1%) of all patients. Retreatment with RFA in 3 patients resulted in a secondary success rate of 77/77 (100%). Long-term follow-up (mean, 38.5 months; range, 3-92) revealed a highly significant (p<0.001) reduction of all assessed limitation scores reaching normal or almost normal values. One major complication, a cannula break leading to a secondary short hospital stay, occurred. In conclusion, RFA is a safe and effective long-lasting treatment of OO and OB. Advanced procedural techniques aid treating tumors in critical locations and in the coverage of larger tumors. Besides night pain, RFA also greatly improves other factors negatively affecting the quality of life.

Morphologic patterns of autoimmune pancreatitis in CT and MRI.

Background/Aims: To retrospectively evaluate the morphologic characteristics of autoimmune pancreatitis (AIP) using MRI and CT. Methods: 86 dynamic contrast-enhanced CT and MRI scans in 36 AIP patients were evaluated regarding: different enlargement types, abnormalities of the main pancreatic duct (MPD), morphology of the parenchyma and other associated findings. Results: 3 types of enlargement were found: (1) a focal type (28%), (2) a diffuse type (involving the entire pancreas, 11%) and (3) a combined type (56%). The MPD was usually dilated together with focal or diffuse narrowing in 67% (24/36). Unenhanced MRI showed AIP area in 56% (mostly T1 hypo- and T2 hyperattenuating), and CT in 10% (hypoattenuating). The arterial phase depicted similar patterns for CT and MRI (hypoattenuating in 58 and 52%, respectively). Venous and late venous phase patterns were usually hyperattenuating in MRI (65 and 74%, late enhancement), while CT mostly showed no signal differences (isoattenuating in 57 and 75%), yielding significant differences between CT and MRI for the venous (p < 0.0001) and the late phase (p = 0.025). Miscellaneous findings were: rim sign (25%), pseudocysts (8%) and infiltration of large vessels (11%). Conclusions: The ‘late-enhancement’ sign seems to be a key feature and is best detectable with MRI. MRI may be recommended in the diagnostic workup of AIP patients.

CT-guided radiofrequency ablation of osteoid osteoma: correlation of clinical outcome and imaging features

PURPOSEnWe aimed to retrospectively evaluate the computed tomography (CT) and magnetic resonance imaging (MRI) findings of patients with osteoid osteoma treated with CT-guided radiofrequency ablation (RFA) along with the clinical outcome and long-term success.nnnMATERIALS AND METHODSnSeventy-three CT-guided RFA procedures were performed in 72 patients. The long-term success was assessed using a questionnaire including several visual analog scale scores. The CT evaluation included pre- and immediate postprocedural imaging of all 72 patients, and MRI was performed in 18 patients with follow-up imaging (mean, 3.4±2.2 months). The evaluation criteria included nidus morphology and a correlation with markers of clinical success.nnnRESULTSnThe primary technique effectiveness rate was 71/72 (99%). One relapse was successfully retreated, leading to a secondary technique effectiveness rate of 72/72 (100%). The long-term follow-up (mean, 51.2±31.2 months; range, 3-109 months) revealed a highly significant reduction of all assessed limitation scores (P < 0.001). The CT morphology was typical in all cases and did not change during the short-term follow-up. The follow-up MRI patterns varied considerably, including persistent nidus contrast enhancement in one-third (6/18) and persistent marrow edema in half (9/18) of the patients. None of the investigated MRI and CT patterns correlated with the clinical outcome.nnnCONCLUSIONnThe long-term outcome of CT-guided RFA of osteoid osteoma is excellent. There is no correlation of the CT and MRI patterns with the clinical outcome. Thus, the treatment decisions should not be solely based on the imaging findings. Investigators should also be aware of the variety of imaging patterns after RFA.

Cartilage imaging of the hand and wrist using 3-T MRI.

The prevalence of osteoarthritis of the hand and wrist is high, and a thorough assessment of even subtle cartilage injuries is necessary before surgical interventions. Although magnetic resonance imaging (MRI) has been established as an important diagnostic tool for the evaluation of hand and wrist disorders, the focus has been on the assessment of the triangular fibrocartilage complex, tendons, ligaments, and the detection of avascular necrosis or occult fractures rather than on cartilage imaging. 3-T MR systems have become more and more widely available and yield an improved signal-to-noise ratio and thus a higher spatial resolution than 1.5-T systems. In principle, this should be especially beneficial for depicting the thin cartilage layers of the hand and wrist. This review focuses on cartilage imaging of the hand and wrist with 3-T MRI and addresses these four topics: (1) the advantages of 3-T versus 1.5- and 1-T MRI, (2) dedicated sequence protocols at 3 T including novel three-dimensional sequences, (3) imaging findings in common cases of overuse or sports injury, and (4) functional cartilage imaging techniques of the hand and wrist, for instance, delayed gadolinium-enhanced MRI of the cartilage.

Left atrial wall dissection, mitral valve prosthesis dehiscence and pericardial hematoma: complex findings after successful cardiac resuscitation

Sirs, A 84-year-old woman, under stable condition after mitral valve replacement with a Hancock bioprosthesis for severe mitral regurgitation secondary to partial rupture chordae tendineae with flail P2 segment with no evidence of papillary muscle compromise, and a saphenous vein graft to the left anterior descending coronary artery was transferred after surgical procedure to the internal medicine intensive care unit. The patient was under permanent mechanical ventilation after successful cardiopulmonary resuscitation in the setting of an acute non-ST elevation myocardial infarction that took place 5 days before surgery. Preserved left ventricular systolic function was confirmed with laevocardiography and with echocardiography during follow-up. Clinical course was stable until 8 days after surgery, when she suddenly deteriorated hemodynamically requiring cardiopulmonary resuscitation. A comprehensive transthoracic and transesophageal echocardiographic examination conducted after successful resuscitation showed a posterior dehiscence of the bioprosthesis with severe para-prosthetic leak, a large hematoma localized posterior to the left ventricle and to the left atrium (Fig. 1a–c, Movies 1–3). This diagnosis was thereafter also documented in a computed tomography conducted during preparation for intervention (Fig. 1d, Movie 4). An emergency surgery conducted afterwards confirmed all but one diagnosis, the effusion at the left atrium was not a pericardial but an intramural hematoma. By reviewing digital images of transesophageal examination offline, a definite pericardial line (Fig. 1a, arrow) could be clearly seen. Surgical repair was attempted, but no substantial compact atrial tissue could be found that would hold the suture, even with use of corresponding surgical patches. Despite heroic efforts, surgery was unsuccessful. Ventricular rupture, valvular dehiscence and atrial dissection are possible complications due to pronounced tissue friability. This condition can be found in older ages, infectious states, myxomatous mitral valve, tissue calcifications, several connective tissue disorders [1], thoracic trauma, cardiopulmonary resuscitation and in acute postoperative phase. Left ventricular rupture after mitral valve replacement is a rare and lethal complication, with an incidence of 0.24% and mortality of 61.5% [2]. Left atrial dissection after mitral valve operation occurs in approximately 0.8% of cases [3]. Higher perioperative risks of cardiac surgical procedures in older ages compared to younger patients are acceptable, with good midand long-term survival. However, combined procedures and increased comorbidity require more resources and have a higher in-hospital mortality [4]. Transesophageal echocardiography is a valuable tool Electronic supplementary material The online version of this article (doi:10.1007/s00392-009-0087-0) contains supplementary material, which is available to authorized users.

Comparison of Modern 3D and 2D MR Imaging Sequences of the Wrist at 3 Tesla

PURPOSEnTo compare the image quality of modern 3u200aD and 2u200aD sequences for dedicated wrist imaging at 3 Tesla (T) MRI.nnnMATERIALS AND METHODSnAt 3u200aT MRI, 18 patients (mean age: 36.2 years) with wrist pain and 16xa0healthy volunteers (mean age: 26.4 years) were examined using 2u200aD proton density-weighted fat-saturated (PDfs), isotropic 3u200aD TrueFISP, 3u200aD MEDIC, and 3u200aD PDfs SPACE sequences. Image quality was rated on a five-point scale (0u200a-u200a4) including overall image quality (OIQ), visibility of important structures (cartilage, ligaments, TFCC) and degree of artifacts. Signal-to-noise ratios (SNR) and contrast-to-noise ratios (CNR) of cartilage/bone/muscle/fluid as well as the mean overall SNR/CNR were calculated using region-of-interest analysis. ANOVA, paired t-, and Wilcoxon-signed-rank tests were applied.nnnRESULTSnThe image quality of all tested sequences was superior to 3u200aD PDfs SPACE (pu200a<u200a0.01). 3u200aD TrueFISP had the highest combined cartilage score (mean: 3.4) and performed better in cartilage comparisons against 3u200aD PDfs SPACE in both groups and 2u200aD PDfs in volunteers (pu200a<u200a0.05). 3u200aD MEDIC performed better in 7 of 8 comparisons (pu200a<u200a0.05) regarding ligaments and TFCC. 2u200aD PDfs provided constantly high scores. The mean overall SNR/CNR for 2u200aD PDfs, 3u200aD PDfs SPACE, 3u200aD TrueFISP, and 3u200aD MEDIC were 68/65, 32/27, 45/47, and 57/45, respectively. 2u200aD PDfs performed best in most SNR/CNR comparisons (pu200a<u200a0.05) and 3u200aD MEDIC performed best within the 3u200aD sequences (pu200a<u200a0.05).nnnCONCLUSIONnExcept 3u200aD PDfs SPACE, all tested 3u200aD and 2u200aD sequences provided high image quality. 3u200aD TrueFISP was best for cartilage imaging, 3u200aD MEDIC for ligaments and TFCC and 2u200aD PDfs for general wrist imaging.nnnKEY POINTSn•u20073u200aD TrueFISP is recommended for cartilage imaging of the wrist at 3u200aT.•u20073u200aD MEDIC is recommended for ligaments and TFCC.•u2007Robust 2u200aD PDfs should be used in routine protocols. 3u200aD sequences may be added depending on the clinical question.•u20073u200aD PDfs SPACE is currently inferior. Citation Format: •u2007Rehnitz C, Klaan B, von Stillfried F etu200aal. Comparison of Modern 3D and 2D MR Imaging Sequences of the Wrist at 3 Tesla. Fortschr Röntgenstr 2016; 188: 753u200a-u200a762.

Osteoidosteoma. From diagnosis to treatment

An osteoid osteoma is a benign bone-forming tumor which usually presents in childhood and adolescence and is characterized by extensive nocturnal pain. Computed tomography (CT) is used to reveal the typical radiolucent nidus surrounded by a sclerotic reaction and in magnetic resonance imaging (MRI) a nidal enhancement and perifocal edema can confirm the diagnosis. Having shown excellent success rates radiofrequency ablation has become the treatment of choice which allows minimally invasive and precise destruction of nidal tumor tissue. By using thermal protection techniques and multiple ablation positions successful therapy of perineural tumors and niduses with diameters of more than 2xa0cm are possible.

Imaging of the Knee Following Repair of Focal Articular Cartilage Lesions

Abstract Focal chondral or osteochondral lesions of the knee are common lesions involving either the cartilage layers or the cartilage layers and the subchondral bone. Despite their heterogeneous clinical presentation, they are important risk factors for the premature development of osteoarthritis. Therefore, early detection of osteochondral lesions and focal cartilage defects is crucial. In symptomatic (osteo‐)chondral lesions, numerous therapeutic strategies, ranging from conservative treatment to surgical procedures such as marrow stimulation, osteochondral autograft transplantation, or autologous chondrocyte implantation are available. Musculoskeletal radiologists should be familiar with these surgical procedures, the evaluation of the postoperative findings as well as the possible complications when interpreting postoperative imaging studies. This review article describes the different surgical approaches to focal osteochondral lesions of the knee with emphasis on postoperative imaging findings and the pitfalls possibly encountered by the radiologist.

Entscheidender radiologischer Befund bei Polytrauma im Schock und Versagen der Volumentherapie

Nach der Anlage zentraler Venenkatheter kommt es in 5–26 % der Falle zu Komplikationen. Diese lassen sich nach ihrer Art in thrombotische, infektiose und mechanische einteilen [4]. Die haufigsten mechanischen Komplikationen machen akzidentelle arterielle Punktionen, Hamatome und Pneumothoraces sowie intravasale Katheterfehllagen aus. n nEin Infusothorax ist eine seltene mechanische Komplikation nach ZVK-Anlage mit Extravasation der uber den Katheter gegebenen Flussigkeiten in den Pleuraspalt, die in weniger als 1 % der Falle nach ZVK-Anlage auftritt [1]. In der englischsprachigen Literatur findet v. a. der allgemeinere Begriff „Hydrothorax“ in diesem Zusammenhang Verwendung. n nUrsachlich ist eine extravasale Lage der Katheterspitze im Mediastinum [5] oder im Pleuraspalt [3], wobei der Katheter entweder, wie im hier beschriebenen Fall, a priori fehlpositioniert sein kann oder mehrere Tage nach Anlage durch Gefasarrosion oder durch akzidentellen Zug sekundar disloziert [2]. n nEine Pradilektionsstelle fur eine Gefasarrosion besteht am Zusammenfluss der Vv. brachiocephalicae (anonymae). Die linke V. anonyma trifft hierbei in einem spitzen Winkel auf die V. cava superior, was Gefaswandverletzungen bei ZVK-Anlagen von links besonders begunstigt [1]. n nHaufige Symptome eines Infusothorax sind Dyspnoe und thorakale Schmerzen [1]. Im hier beschriebenen Fall hatte v. a. das fehlende Ansprechen auf die Volumen- und Katecholamingabe an einen fehlpositionierten ZVK denken lassen konnen, was sich im Nachhinein und ohne Schockraumbedingungen naturgemas leichter sagen lasst. In der klinischen Untersuchung wie auch im konventionellen Rontgenbild dominiert ein haufig sehr ausgepragter Pleuraerguss. Bereits projektionsradiographisch lasst sich in den meisten Fallen eine extravasale Lage des Katheters nachweisen (Abb. 4). n nOpen image in new window n nAbb. 4 nEin weiterer Fall eines Infusothorax. a Neu eingebrachter zentralvenoser Katheter von rechts jugular in Projektion rechts-lateral der V. cava superior mit geringem Pleuraerguss. Die Fehllage wurde initial ubersehen. b 24 h spater Bild eines ausgepragten Infusothorax mit subtotaler Verschattung des rechten Hemithorax. c Weitere 7 h spater nach Zug des Katheters nahezu vollstandige Regredienz des Ergusses n n nHauptzeichen, die fur eine Fehllage eines ZVK sprechen: n n nkein suffizientes Aspirieren von Blut uber den Katheter, n n nfehlendes klinisches Ansprechen auf uber den ZVK gegebene Medikamente oder Flussigkeiten, n n nDyspnoe, thorakale Schmerzen (in engem zeitlichen Zusammenhang mit der ZVK Anlage), n n nungewohnlicher Verlauf des ZVK, Spitze nicht in Projektion auf die V. cava superior in der Projektionsradiographie oder auf dem Topogramm des CTs (beachte: ein Blick auf das Topogramm eines „Schockraum-CTs“ ist haufig hilfreich), n n nzunehmende Pleuraergusse, mediastinale Verbreiterung, Hamatom/Verschattung der Lungenapices.

Entscheidender radiologischer Befund bei Polytrauma im Schock und Versagen der Volumentherapie@@@Decisive radiological findings in multiple trauma and shock unresponsive to volume therapy

Nach der Anlage zentraler Venenkatheter kommt es in 5–26 % der Falle zu Komplikationen. Diese lassen sich nach ihrer Art in thrombotische, infektiose und mechanische einteilen [4]. Die haufigsten mechanischen Komplikationen machen akzidentelle arterielle Punktionen, Hamatome und Pneumothoraces sowie intravasale Katheterfehllagen aus. n nEin Infusothorax ist eine seltene mechanische Komplikation nach ZVK-Anlage mit Extravasation der uber den Katheter gegebenen Flussigkeiten in den Pleuraspalt, die in weniger als 1 % der Falle nach ZVK-Anlage auftritt [1]. In der englischsprachigen Literatur findet v. a. der allgemeinere Begriff „Hydrothorax“ in diesem Zusammenhang Verwendung. n nUrsachlich ist eine extravasale Lage der Katheterspitze im Mediastinum [5] oder im Pleuraspalt [3], wobei der Katheter entweder, wie im hier beschriebenen Fall, a priori fehlpositioniert sein kann oder mehrere Tage nach Anlage durch Gefasarrosion oder durch akzidentellen Zug sekundar disloziert [2]. n nEine Pradilektionsstelle fur eine Gefasarrosion besteht am Zusammenfluss der Vv. brachiocephalicae (anonymae). Die linke V. anonyma trifft hierbei in einem spitzen Winkel auf die V. cava superior, was Gefaswandverletzungen bei ZVK-Anlagen von links besonders begunstigt [1]. n nHaufige Symptome eines Infusothorax sind Dyspnoe und thorakale Schmerzen [1]. Im hier beschriebenen Fall hatte v. a. das fehlende Ansprechen auf die Volumen- und Katecholamingabe an einen fehlpositionierten ZVK denken lassen konnen, was sich im Nachhinein und ohne Schockraumbedingungen naturgemas leichter sagen lasst. In der klinischen Untersuchung wie auch im konventionellen Rontgenbild dominiert ein haufig sehr ausgepragter Pleuraerguss. Bereits projektionsradiographisch lasst sich in den meisten Fallen eine extravasale Lage des Katheters nachweisen (Abb. 4). n nOpen image in new window n nAbb. 4 nEin weiterer Fall eines Infusothorax. a Neu eingebrachter zentralvenoser Katheter von rechts jugular in Projektion rechts-lateral der V. cava superior mit geringem Pleuraerguss. Die Fehllage wurde initial ubersehen. b 24 h spater Bild eines ausgepragten Infusothorax mit subtotaler Verschattung des rechten Hemithorax. c Weitere 7 h spater nach Zug des Katheters nahezu vollstandige Regredienz des Ergusses n n nHauptzeichen, die fur eine Fehllage eines ZVK sprechen: n n nkein suffizientes Aspirieren von Blut uber den Katheter, n n nfehlendes klinisches Ansprechen auf uber den ZVK gegebene Medikamente oder Flussigkeiten, n n nDyspnoe, thorakale Schmerzen (in engem zeitlichen Zusammenhang mit der ZVK Anlage), n n nungewohnlicher Verlauf des ZVK, Spitze nicht in Projektion auf die V. cava superior in der Projektionsradiographie oder auf dem Topogramm des CTs (beachte: ein Blick auf das Topogramm eines „Schockraum-CTs“ ist haufig hilfreich), n n nzunehmende Pleuraergusse, mediastinale Verbreiterung, Hamatom/Verschattung der Lungenapices.