G. Christopoulos

Congenital anomalies of the coronary arteries: imaging with contrast-enhanced, multidetector computed tomography

The objective of this study is to evaluate multidetector CT (MDCT) in detecting and characterizing anomalous coronary arteries. Forty-four patients with anomalies of the coronaries were selected from a total of 1758 individuals examined with ECG-gated 4- and 16-row MDCT including thinMIP, MPR and VRT post-processing. Twenty-eight patients showed origin and course anomalies of the central coronary segments, and in this subgroup 13 were judged as “malignant” because of interarterial courses between the aortic root and the pulmonary trunk, either of the right coronary artery (n=11) or the left coronary artery (n=2). Twelve non-hemodynamic anomalies were found, affecting the coronary origins only (n=10) or the peripheral vessels courses (n=2). Four arteriovenous fistulas were present, all of them with complex arterial feeders. Regardless of vessel anatomy, coronary opacification was always possible by means of the systemic contrast agent, and the aberrant coronary arteries were visualized synoptically in direct relation to the great mediastinal vessels. In contrast to MDCT, selective cannulation and final diagnosis was possible in only 11 of the 20 catheter angiograms performed (accuracy of 55.0%). In conclusion, its non-invasiveness and precise visualization makes MDCT the standard of reference for evaluating anomalous coronary arteries.

Avascular necrosis (AVN) of the proximal fragment in scaphoid nonunion: Is intravenous contrast agent necessary in MRI?

PURPOSE The purpose of this prospective study is to assess the diagnostic value of intravenously applied contrast agent for diagnosing osteonecrosis of the proximal fragment in scaphoid nonunion, and to compare the imaging results with intraoperative findings. MATERIALS AND METHODS In 88 patients (7 women, 81 men) suffering from symptomatic scaphoid nonunion, preoperative MRI was performed (coronal PD-w FSE fs, sagittal-oblique T1-w SE nonenhanced and T1-w SE fs contrast-enhanced, sagittal T2*-w GRE). MRI interpretation was based on the intensity of contrast enhancement: 0 = none, 1 = focal, 2 = diffuse. Intraoperatively, the osseous viability was scored by means of bleeding points on the osteotomy site of the proximal scaphoid fragment: 0=absent, 1 = moderate, 2 = good. RESULTS Intraoperatively, 17 necrotic, 29 compromised, and 42 normal proximal fragments were found. In nonenhanced MRI, bone viability was judged necrotic in 1 patient, compromised in 20 patients, and unaffected in 67 patients. Contrast-enhanced MRI revealed 14 necrotic, 21 compromised, and 53 normal proximal fragments. Judging surgical findings as the standard of reference, statistical analysis for nonenhanced MRI was: sensitivity 6.3%, specificity 100%, positive PV 100%, negative PV 82.6%, and accuracy 82.9%; statistics for contrast-enhanced MRI was: sensitivity 76.5%, specificity 98.6%, positive PV 92.9%, negative PV 94.6%, and accuracy 94.3%. Sensitivity for detecting avascular proximal fragments was significantly better (p<0.001) in contrast-enhanced MRI in comparison to nonenhanced MRI. CONCLUSION Viability of the proximal fragment in scaphoid nonunion can be significantly better assessed with the use of contrast-enhanced MRI as compared to nonenhanced MRI. Bone marrow edema is an inferior indicator of osteonecrosis. Application of intravenous gadolinium is recommended for imaging scaphoid nonunion.

Comprehensive MR angiography of the lower limbs: a hybrid dual-bolus approach including the pedal arteries

The purpose of this study was to include the pedal vasculature into the coverage of peripheral multistation magnetic resonance angiography (3DceMRA). A total of 216 patients suffering from peripheral vascular disease were examined with a modified hybrid dual-bolus technique. The cruropedal arteries were acquired first with two sagittal slabs and time-resolved 3D sequences. Then the aortofemoral vessels were visualized using the bolus-chase technique and a second contrast injection. Interventional procedures were performed in 104 patients, and in 69 of those, the cruropedal vessels were also examined with digital subtraction angiography (iaDSA). Using 3DceMRA, the cruropedal arteries were displayed with both excellent and good quality in 95% (205/216 cases), and without any venous overlay in 94% (203/216 cases). The aortofemoral vessels were not jeopardized by the first contrast injection. With iaDSA as the standard of reference, observed sensitivity of 3DceMRA was found in ranges from 80% (29%, 99%) to 100% (86%, 100%) for assessing significant stenoses, and observed specificity ranged between 93% [80%, 98%] and 100% (82%, 100%). In conclusion, hybrid dual-bolus 3DceMRA significantly reduces the limitations of standard single-bolus 3DceMRA in anatomic coverage and temporal resolution of the cruropedal arteries, thus providing high-quality images of the entire peripheral vasculature.

[TFCC-lesion. MR arthrography vs. arthroscopy of the wrist].

ZusammenfassungIn einer ‘geblindeten’ Studie wurden von Januar bis Juli 2000 prospektiv 125 Patienten mit klinischem Verdacht auf eine Handgelenkverletzung mittels Arthro-MRT untersucht. Innerhalb von 24 h erfolgte eine Handgelenkarthroskopie.Anhand der Arthro-MRT-Befunde wurde bei 70 Patienten bzw.56% des Gesamtkrankengutes eine Verletzung des TFCC gefunden.Bei 65 Patienten konnte dies arthroskopisch bestätigt werden. Bei den übrigen 55 Patienten wurde in der Arthro-MRT keine TFCC-Läsion diagnostiziert. Jedoch fanden sich in 3 Fällen, in denen der kernspintomographische Befund einen intakten TFCC vermuten ließ, arthroskopisch Läsionen. In den übrigen 52 Fällen konnte die MRT eine Verletzung des ulnokarpalen Komplexes korrekt ausschließen.Eine Übereinstimmung der MRT und Arthroskopieergebnisse konnte also in 93,6% der Fälle ermittelt werden (Korrelation). Die mittels MRT gestellte Diagnose einer TFCC-Läsion war in 94% der Fälle richtig (Sensitivität), der Ausschluss einer derartigen Verletzung in 89% (Spezifität).Positive bzw.negative prädiktive Werte von 91% bzw.93% wurden erreicht. Da derzeit weder eine Spezifität noch eine Sensitivität von 100% erreicht wird, kann die Arthro-MRT die Arthroskopie nicht ersetzen. Sie stellt jedoch durch die oben gezeigten hohen Trefferquoten bei intraartikulärer Verwendung von Kontrastmittel eine wertvolle ergänzende Untersuchungsmethode dar, die dem Chirurgen die Diagnostik und die Indikationsstellung zur operativen Intervention am ulno-karpalen Handgelenkkompartiment erleichtern und zur Reduzierung der rein diagnostischen Handgelenkeingriffe ohne therapeutische Konsequenzen beitragen kann.Bei zunehmend verbesserter MRT-Technik darf man noch Verbesserungen der Trefferquote und des klinischen Nutzens der MRT-Untersuchung zur Diagnostik am ulnokarpalen Handgelenk erwarten.AbstractIn a blinded study from January to July 2000, 125 patients suffering from specific complaints of the wrist were examined with direct MR arthrography prospectively.Within 24 hours an arthroscopy of the wrist was performed.With the MR arthrography in 70 patients or 56% of all patients injury of the TFCC was diagnosed. In 65 patients this could be verified arthroscopically. In the remaining 55 patients no TFCC lesion was diagnosed with the MR arthrography.However lesions were found via arthroscopy in three cases,were MRI findings expected an intact TFCC. In the remaining 52 cases the MRT could exclude a lesion of the TFCC correctly.An agreement of the MRT and arthroscopic results could be determined in 93,6% of the cases (correlation).The diagnosis of a TFCC lesion by means of MRI was correct in 94% of the cases (sensitivity), the exclusion of such lesion in 89% (specificity).Positive or negative predictive values of 91% or 93% were achieved. Since neither a specificity nor a sensitivity of 100% can be reached at the moment, the MR arthrography cannot replace the arthroscopy.However it could be a potent additional tool for wrist diagnosis if intraarticular contrast is used. It can facilitate the diagnostics and the indication for surgery at the ulnocarpal wrist and help to reduce arthoscopic interventions that are only for diagnostic purposes and without any therapeutic consequences.With improvement of the technique of magnet resonance tomography we can expect further increase of accuracy and the clinical use of the MR arthrography in the diagnostic workup at the ulnocarpal wrist.

[Scaphoid fracture and nonunion: current status of radiological diagnostics].

ZusammenfassungSkaphoidfrakturen, die ca. 2/3 aller Verletzungen am Handgelenk ausmachen, entziehen sich häufig dem Nachweis in der radiologischen Erstdiagnostik. Mit der hochaufgelösten CT und der dezidiert durchgeführten MRT stehen mittlerweile Werkzeuge zur Verfügung, die die Detektion der Skaphoidfraktur bereits am Unfalltag ermöglichen und eine Abschätzung der Fragmentstabilität erlauben. Dabei kann die CT therapierelevante Informationen sowohl zum Frakturausmaß als auch zur Therapiekontrolle liefern. Die MRT weist Skaphoidfrakturen am sensitivsten nach, jedoch müssen diese sicher gegenüber einem „bone bruise“ abgegrenzt werden. Bei primär übersehener Fraktur oder nicht erfolgter Konsolidierung kann sich nachfolgend eine Skaphoidpseudarthrose stadienhaft entwickeln. Die CT gibt wichtige Detailinformationen zur knöchernen Morphologie des Kahnbeins, die kontrastmittelverstärkte MRT zur Vitalitätsbeurteilung des proximalen Skaphoidfragments.AbstractScaphoid fractures, which involve approximately two-thirds of all wrist injuries, are often not detected during initial radiographic examination. By using high-resolution CT and dedicated MRI, it is possible to recognize scaphoid fractures soon at the first diagnostic approach and to assess fragment stability. CT imaging provides all the relevant information of the fracture extent and of the fracture healing in the follow-up. MRI is most sensitive in the detection of scaphoid fractures; however, fracture signs must be differentiated from those of a bone bruise. Both the initially overseen scaphoid fracture and the unsuccessful healing can lead to the natural history of scaphoid nonunion. In the injured scaphoid, CT imaging is essential for depicting the osseous morphology, whereas contrast-enhanced MRI is crucial for assessing the viability of the proximal fragment.

Skaphoidfraktur und -pseudarthrose@@@Scaphoid fracture and nonunion: Eine aktuelle Standortbestimmung der radiologischen Diagnostik@@@Current status of radiological diagnostics

ZusammenfassungSkaphoidfrakturen, die ca. 2/3 aller Verletzungen am Handgelenk ausmachen, entziehen sich häufig dem Nachweis in der radiologischen Erstdiagnostik. Mit der hochaufgelösten CT und der dezidiert durchgeführten MRT stehen mittlerweile Werkzeuge zur Verfügung, die die Detektion der Skaphoidfraktur bereits am Unfalltag ermöglichen und eine Abschätzung der Fragmentstabilität erlauben. Dabei kann die CT therapierelevante Informationen sowohl zum Frakturausmaß als auch zur Therapiekontrolle liefern. Die MRT weist Skaphoidfrakturen am sensitivsten nach, jedoch müssen diese sicher gegenüber einem „bone bruise“ abgegrenzt werden. Bei primär übersehener Fraktur oder nicht erfolgter Konsolidierung kann sich nachfolgend eine Skaphoidpseudarthrose stadienhaft entwickeln. Die CT gibt wichtige Detailinformationen zur knöchernen Morphologie des Kahnbeins, die kontrastmittelverstärkte MRT zur Vitalitätsbeurteilung des proximalen Skaphoidfragments.AbstractScaphoid fractures, which involve approximately two-thirds of all wrist injuries, are often not detected during initial radiographic examination. By using high-resolution CT and dedicated MRI, it is possible to recognize scaphoid fractures soon at the first diagnostic approach and to assess fragment stability. CT imaging provides all the relevant information of the fracture extent and of the fracture healing in the follow-up. MRI is most sensitive in the detection of scaphoid fractures; however, fracture signs must be differentiated from those of a bone bruise. Both the initially overseen scaphoid fracture and the unsuccessful healing can lead to the natural history of scaphoid nonunion. In the injured scaphoid, CT imaging is essential for depicting the osseous morphology, whereas contrast-enhanced MRI is crucial for assessing the viability of the proximal fragment.

Skaphoidfraktur und -pseudarthrose

ZusammenfassungSkaphoidfrakturen, die ca. 2/3 aller Verletzungen am Handgelenk ausmachen, entziehen sich häufig dem Nachweis in der radiologischen Erstdiagnostik. Mit der hochaufgelösten CT und der dezidiert durchgeführten MRT stehen mittlerweile Werkzeuge zur Verfügung, die die Detektion der Skaphoidfraktur bereits am Unfalltag ermöglichen und eine Abschätzung der Fragmentstabilität erlauben. Dabei kann die CT therapierelevante Informationen sowohl zum Frakturausmaß als auch zur Therapiekontrolle liefern. Die MRT weist Skaphoidfrakturen am sensitivsten nach, jedoch müssen diese sicher gegenüber einem „bone bruise“ abgegrenzt werden. Bei primär übersehener Fraktur oder nicht erfolgter Konsolidierung kann sich nachfolgend eine Skaphoidpseudarthrose stadienhaft entwickeln. Die CT gibt wichtige Detailinformationen zur knöchernen Morphologie des Kahnbeins, die kontrastmittelverstärkte MRT zur Vitalitätsbeurteilung des proximalen Skaphoidfragments.AbstractScaphoid fractures, which involve approximately two-thirds of all wrist injuries, are often not detected during initial radiographic examination. By using high-resolution CT and dedicated MRI, it is possible to recognize scaphoid fractures soon at the first diagnostic approach and to assess fragment stability. CT imaging provides all the relevant information of the fracture extent and of the fracture healing in the follow-up. MRI is most sensitive in the detection of scaphoid fractures; however, fracture signs must be differentiated from those of a bone bruise. Both the initially overseen scaphoid fracture and the unsuccessful healing can lead to the natural history of scaphoid nonunion. In the injured scaphoid, CT imaging is essential for depicting the osseous morphology, whereas contrast-enhanced MRI is crucial for assessing the viability of the proximal fragment.