Arthroscintigraphy in Suspected Rotator Cuff Rupture

Aim: In order to evaluate the diagnostic efficiency of arthroscintigraphy in suspected rotator cuff ruptures this new imaging procedure was performed 20 times in 17 patients with clinical signs of a rotator cuff lesion. The scintigraphic results were compared with sonography (n = 20), contrast arthrography (n = 20) and arthroscopy (n = 10) of the shoulder joint. Methods: After performing a standard bone scintigraphy with intravenous application of 300 MBq 99m-Tc-methylene diphosphonate (MDP) for landmarking of the shoulder region arthroscintigraphy was performed after an intraarticular injection of 99m-Tc microcolloid (ALBURES 400 μCi/5 ml). The application was performed either in direct combination with contrast arthrography (n = 10) or ultrasound conducted mixed with a local anesthetic (n = 10). Findings at arthroscopical surgery (n = 10) were used as the gold standard. Results: In case of complete rotator cuff rupture (n = 5), arthroscintigraphy and radiographic arthrography were identical in 5/5. In one patient with advanced degenerative alterations of the shoulder joint radiographic arthrography incorrectly showed a complete rupture which was not seen by arthroscintigraphy and endoscopy. In 3 patients with incomplete rupture, 2/3 results were consistant. A difference was seen in one patient with a rotator cuff, that has been already revised in the past and that suffered of capsulitis and calcification. Conclusion: Arthroscintigraphy is a sensitive technique for detection of rotator cuff ruptures. Because of the lower viscosity of the active compound, small ruptures can be easily detected, offering additional value over radiographic arthrography and ultrasound, especially for evaluation of incomplete cuff ruptures.

[Acute aortic diseases. Diagnostic imaging and therapy]

Diagnostic imaging is crucial in the work-up of acute aortic diseases. Current imaging algorithms enable radiologists differentiating the various entities with subsequent clinically relevant treatment options. Within this educational overview we focus on non-traumatic acute aortic disease. Recent developments of cross sectional imaging are summarized. As for acute aortic disease, we discuss dissections, intramural hematoma, penetrating aortic ulcer, and aortitis. Current treatment options are presented.

[Contrast agents in radiology: current agents approved, recommendations, and safety aspects]

The manuscript summarizes current approved contrast media and their indications. Contrast agents that are discussed include iodinated contrast agents, magnetic resonance (MR) contrast agents, and ultrasound contrast agents. Allergic and non-allergic renal adverse events are described. The clinical issue of metformin and the administration of contrast agents are updated. Nephrogenic systemic fibrosis (NSF) is discussed and safety issues of available MR contrast agents are analyzed. The most recent changes in European Society of Urogenital Radiology (ESUR) guidelines are also presented.

[Cerebral vasculitis associated with gemcitabine]

Neoadjuvant chemotherapy consisting of cisplatin and gemcitabine was given to a 50-year-old woman suffering from transitional cell carcinoma of the bladder. Whereas the first cycle was administered without major side effects, the patient experienced a generalized tonic-clonic seizure and a prolonged cognitive deficit with the second cycle. Magnetic resonance imaging of the brain was consistent with cerebral vasculitis. The short interval between the application of gemcitabine and the neurological deterioration suggests a causal relationship. Although recent reports have linked this drug with leukoencephalopathy and vasculitis in various localizations, this is the first case of cerebral vasculitis associated with gemcitabine.

Nephrogenic systemic fibrosis

Nephrogenic systemic fibrosis (NSF) is a relative new disease affecting predominantly patients with severely impaired kidney function. Strict adherence to a concordant clinical and pathological definition has allowed for careful separation of this entity from other fibrosing disorders, leading eventually to the realization that gadolinium based contrast agents were closely associated with its onset. Gadodiamide and similarly unstable Gd-CA should therefore not be used in patients with renal insufficiency. The clinical symptoms of NSF vary considerably from patient to patient. NSF should be suspected in renal failure patients presenting any possible NSF symptom appearing in the weeks after Gd-enhanced MRI. Suspected cases should have a skin biopsy taken from an affected region for the histological confirmation or rejection of the diagnosis. There are no established curative treatments to NSF patients. Prevention is the only alternative. Guidelines for the daily routine seem to be the right way. When NSF is identified the primary goal is reversal of underlying renal failure or renal transplantation. In addition, use of physical therapy and pain control is mandatory. One of the best news in late 2007 is the decreasing rate of newly detected NSF cases. In the case this development continues, NSF may become an historical disease in the near future.

Off-label use of contrast agents

When contrast agents are approved, the label describes the approved indications and particular circumstances of use such as age, organ function or pregnancy. The use of contrast agents outside their labelled indications is increasing, namely with contrast agents used for MRI. The aim of this paper is to improve the knowledge about this topic. The basis for off-label use is the physician's prerogative, which finds its basis in the "Declaration of Helsinki". Off-label use is allowed under special conditions and might be even the medical state of the art. The necessity for off-label use will continue to increase for MR-contrast agents, as the regulatory requirements for approval of new indications continuously increase, and clinical trials for registration purposes are quite costly and time consuming. As a consequence, manufacturers will concentrate on clinical studies for the essential indications.

[Peripheral arteries]

Peripheral arterial disease is a main cause of morbidity in industrialised countries. It chiefly affects older people. The most common causes are atherosclerosis and vasodilatatory abnormalities. In the presence of unexplained leg symptoms, peripheral arterial disease can be diagnosed or ruled out by non-invasive diagnostic methods such as history, clinical examination and the measurement of ankle and brachial artery pressure by Doppler ultrasound, as well as by calculating the ankle brachial index. Colour coded duplex sonography, computer tomography angiography, magnetic resonance angiography and arteriography are the imaging modalities used. Current diagnostic strategies are analysed for the different peripheral artery diseases.

[Imaging of aortic disease]

Diseases of the aorta are imaged using different modalities according to the cause and clinical situation. Current imaging strategies for the clinically most pertinent aortic diseases are analysed. These disease entities may be differentiated into congenital, acquired and inflammatory diseases. Traumatic and non-traumatic aortic aneurysms and dissections are emphasised in context with endovascular treatment options and subsequent follow-up.

[Magnetic resonance imaging as the primary diagnostic method for ectopic discharging ureteral insertion of a dysplastic kidney]

Ectopic ureters associated with dysplastic kidneys remain a diagnostic dilemma. Ultrasound, endoscopy as well as intravenous urography do not always show correct urinary tract morphology and function. We report the case of a 6-year-old girl with continuous urine dribbling to demonstrate the diagnostic value of MR urography.

Diagnosis and follow up of aortitis in the elderly

OBJECTIVES

To evaluate the correlation of MRI and [(18)F]FDG-PET scans with the clinical course and inflammatory markers in patients with aortitis.

METHODS

Eight patients with aortitis presenting with unspecific GCA-like symptoms were examined. Aortitis was diagnosed and followed up by [(18)F]FDG-PET and MRI. The aorta was divided into three vascular regions (ascending aorta, aortic arch, and descending aorta) to localise the aortic inflammation and compare both imaging techniques.

RESULTS

were correlated with clinical and laboratory examinations.

RESULTS

At diagnosis, 20/24 vascular regions from eight patients were positive by [(18)F]FDG-PET scan and 15/21 aortic regions by MRI. Patients were treated with corticosteroids and followed up for a mean (SD) of 13.3 (4.7) months. In [(18)F]FDG-PET, 11/20 (55%) initially pathological aortic regions returned to normal in the follow up examination, which correlated closely with the clinical and laboratory follow up examination. Conversely, in MRI, 14/15 initially affected vascular regions were unchanged.

CONCLUSIONS

[(18)F]FDG-PET and MRI are both effective techniques for detecting early aortitis and have a high correlation with laboratory inflammatory measures. However, during the follow up examination, [(18)F]FDG-PET uptake decreased in line with the clinical symptoms and inflammatory serum markers, whereas MRI scans gave more static results.

Kontrastmittel in der MRT

The use of intravenous contrast agents in magnetic resonance imaging (MRI) has become well established clinical practice. Contrast agents provide additional information in many applications. Gadolinium chelates constitute the largest group of MR contrast agents and are considered to be safe. Different groups of contrast agents are established for clinical application: low concentrated gadolinium chelates, high concentrated gadolinium chelates, superparamagnetic iron oxide particles and hepatobiliary contrast agents. The review discusses the clinical applications and the safety issues involved with administration of intravenous contrast agents in MR imaging. Several approaches of intravascular or blood pool agents are also presented.

[Contrast-enhanced MR angiography of the arterial and portovenous system of the liver with varying concentrations of contrast medium]

PURPOSE

To evaluate the diagnostic value of a higher concentrated contrast medium (gadobutrol) for contrast-enhanced MRA of the hepatic arteries and portovenous system.

MATERIALS AND METHODS

The examinations were performed on a 1.5-Tesla whole body imaging system (Magnetom Symphony Quantum, Siemens) with a 30-mTesla/m gradient field strength using a phased-array body coil. A 3D FLASH sequence (TR/TE/FA 3.88 ms/1.44 ms/25(3)) was used imaging the hepatic arteries and portovenous system after determination of the circulation time. The study included 50 patients, with 25 patients (group 1) injected with 0.2 mmol Gd-GTPA/kg body weight and 25 patients (group 2) injected with 0.1 mmol gadobutrol/kg body weight. The signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR) were calculated for both groups. The image quality was graded by three radiologists on a 5-point scale.

RESULTS

The highest SNR was measured in group 1, with no statistically significant differences of the SNR in the abdominal aortal, coeliac trunk and common hepatic artery. CNR was also similar in both groups. Likewise, portal, superior mesenteric and splenic veins showed no statistically significant differences. All cases were found to have a good image quality.

CONCLUSION

For MRA of the hepatic arteries and the portal veins, the higher concentrated Gd-DTPA contrast medium gadobutrol can be used at half the dosage recommended for the standard Gd-DTPA contrast medium.

MRI in the evaluation of müllerian duct anomalies

OBJECTIVE

Müllerian duct anomalies (MDAs) result from nondevelopment or nonfusion of the müllerian ducts and occur in 1-5% of women. Accurate diagnosis of the various subtypes is of great importance as MDAs are frequently associated with a broad variety of clinical symptoms. Recently, evidence arose that MRI might play a major role in diagnosis of MDAs. We present four cases of diverse subtypes of MDAs and the corresponding MRI findings.

MATERIALS AND METHODS

Patients (n = 4) with clinical suspicion of MDAs were examined with MRI. Coronal and transaxial T1- and T2-weighted images were acquired. Diagnosis was made and patients were grouped according to the American Fertility Society's classification. Patients underwent laparoscopy or laparotomy in order to confirm the diagnosis.

RESULTS

MRI revealed MDAs in all patients. In detail, one patient was diagnosed with hypoplastic uterus, one with unicornuate uterus with a noncommunicating rudimentary horn, one with bicornuate uterus bicollis with a double vagina and one with septate uterus. MRI diagnosis was correct in all cases, as confirmed by subsequent surgical intervention.

CONCLUSION

MRI is a valuable tool in diagnosis of MDA subtypes. Its use will help to spare patients mutilating surgery and to prevent pregnancy-associated complications.

[Refixation of osteochondral fragments using absorbable implants. First results of a retrospective study]

An osteochondral lesion in a weight bearing joint causes therapeutic problems. Surgical therapy focuses on the restoration of the articular surface, unlimited motion of the joint and prevention of cartilaginous degeneration. A causal therapy to prevent posttraumatic osteoarthritis is the fixation of osteochondral fragments. Various absorbable implants for the purpose of refixation are available, but only a few have proved to be biocompatible. This retrospective study presents the preliminary results after refixation of osteochondral fragments of the ankle and knee joints. We used self-reinforced absorbable pins, nails and screws made of polylactide acid. The results for 15 patients with 17 fractures of 16 joints were evaluated. All patients were scored by the Tegner-activity-level, the McDermott-score and the DGKKT-score, and 13 of them were monitored by postoperative magnetic resonance imaging (MRI). The follow-up extended for an average of 14.3 months (range: 4-43 months). The clinical results for all patients were good (McDermott-score: Ø 89 points, DGKKT-score: Ø 78.8 points, Tegner: pre-op vs post-op=Ø 4.6 vs Ø 5.1) and the surgical therapy proved to be successful. The MRI showed the complete incorporation and vitality of the fragment as well as a congruence of the joint surface. The clinical course and the MRI gave little reference to an inflammatory reaction due to the implants that complicated the course of two patients. These results indicate that absorbable implants made of polylactide acid are biocompatible and effective in the fixation of osteochondral fragments.

Early diagnosis and follow-up of aortitis with [(18)F]FDG PET and MRI

The aim of this prospective study was to compare fluorine-18 fluorodeoxyglucose ([(18)F]FDG) positron emission tomography (PET) with magnetic resonance imaging (MRI) in patients with early aortitis, at the time of initial diagnosis and during immunosuppressive therapy. The study population consisted of 15 patients (nine females and six males; median age 62 years, range 26-76 years) who presented with fever of unknown origin or an elevated erythrocyte sedimentation rate or elevated C-reactive protein and who showed pathological aortic [(18)F]FDG uptake. Fourteen of these patients had features of early giant cell arteritis (GCA), while one had features of early Takayasu arteritis. During follow-up, seven PET scans were performed in six patients with GCA 4-30 months (median 19 months) after starting immunosuppressive medication. The results of [(18)F]FDG imaging were compared with the results of MRI at initial evaluation and during follow-up and with the clinical findings. At baseline, abnormal [(18)F]FDG uptake was present in 59/104 (56%) of the vascular regions studied in 15 patients. Seven follow-up PET studies were performed in six patients. Of 30 regions with initial pathological uptake in these patients, 24 (80%) showed normalisation of uptake during follow-up. Normalisation of [(18)F]FDG uptake correlated with clinical improvement and with normalisation of the laboratory findings. All except one of the patients with positive aortic [(18)F]FDG uptake were investigated with MRI and MRA. Thirteen of these 14 patients showed inflammation in at least one vascular region. Of 76 vascular regions studied, 41 (53%) showed vasculitis on MRI. Of 76 vascular regions studied with both PET and MRI, 47 were concordantly positive or negative on both modalities, 11 were positive on MRI only and 18 were positive on PET only. MRI was performed during follow-up in six patients: of 17 regions with inflammatory changes, 15 regions remained unchanged and two showed improvement. Whole-body [(18)F]FDG PET is valuable in the primary diagnosis of early aortitis. The results of [(18)F]FDG PET and MRI in the diagnosis of aortitis in this study were comparable, but FDG imaging identified more vascular regions involved in the inflammatory process than did MRI. In a limited number of patients [(18)F]FDG PET was more reliable than MRI in monitoring disease activity during immunosuppressive therapy.

Value of F-18 FDG hybrid camera PET and MRI in early takayasu aortitis

Takayasu aortitis (TA) is a chronic inflammatory and fibrotic vasculitis of large- and medium-sized arteries. Early stages of the disease show a panarteritis and inflammatory wall thickening of the aorta and its branches, whereas advanced (fibrotic) stages comprise stenosis, aneurismatic transformation and occlusion. Magnetic resonance imaging visualises early-stage disease with high accuracy and is considered to be the method of choice in the diagnosis of TA. The aim of this article is the detailed comparison of FDG-PET performed with a hybrid camera and MR imaging in five patients with early TA. Five patients (median age 60 years) were enrolled during an ongoing prospective study on [18F]2'-deoxy-2-fluoro-D-glucose (FDG) hybrid camera PET in patients with fever of unknown origin (FUO). These patients underwent MR imaging after establishing the diagnosis of TA. Abnormal FDG uptake in the wall of the aorta was noted in all patients. The bracheocephalic artery and the common carotid arteries were visualized in 3 cases. Increased uptake of the subclavian artery was found in 3 patients and in 4 patients pathological uptake was noted in the ilio-femoral vessels. Of 34 vascular regions studied, 26 (76%) showed elevated FDG uptake. On transversal MR images vessel wall thickening and contrast enhancement of the thoracic aorta was found in 4 patients (ascending aorta/aortic arch: n=2; descending aorta: n=3; abdominal aorta: n=1). Additionally, vessel wall pathologies of the subclavian and the common carotid arteries could be shown in 1 patient and in another patient in the ilio-femoral arteries. No abnormalities were found using contrast-enhanced MR angiography. Of 28 vascular regions studied, 9 (32%) showed vasculitis on MRI. The FDG-PET is a suitable whole-body screening method in the primary diagnosis of early TA, especially in those cases with early disease that present with uncharacteristic symptoms such as FUO. Both MRI and MRA remain indispensable in the exact determination of the pathomorphological changes and in the documentation of complications such as stenosis, aneurismatic transformation and occlusion.

Comparative study in patients with microcalcifications: full-field digital mammography vs screen-film mammography

The goal of this prospective study was to compare a full-field digital mammography system (FFDM) to a conventional screen-film mammography system (SFM) for the detection and characterization of microcalcifications. Fifty-five patients with 57 isolated microcalcification clusters were examined using a FFDM system (Senographe 2000D, GE Medical Systems, Milwaukee, Wis.) and a SFM system (Senographe DMR, GE Medical Systems, Milwaukee, Wis.). A conventional screen-film mammogram and a digital contact mammogram were obtained of each cluster. The image quality and the number of calcification particles were evaluated, and a characterization (BI-RADS 1-5) of microcalcifications was given by four experienced readers. Histopathology revealed 16 benign lesions (sclerosing adenosis, dysplasia, hamartoma, radial scar) in 15 patients and 21 malignant tumors (in situ carcinoma, invasive carcinoma) in 20 patients. Twenty patients had benign changes verified by long-term follow-up. Image quality of FFDM was assessed as superior to SFM in more than 50% of the cases. The FFDM showed more calcifications in 41% of all cases. Sensitivity and specificity for FFDM vs SFM were 95.2 vs 91.9% and 41.4 vs 39.3%, respectively. Moreover, FFDM demonstrated a higher diagnostic accuracy (deviation: 0.86 BI-RADS steps) compared with FSM (deviation 0.93 BI-RADS steps). The FFDM system with a 100- micro m pixel size provides better image quality than SFM in patients with mammographic microcalcifications. The FFDM has a higher sensitivity and a higher reliability in characterizing microcalcifications.

[Quality management in a radiology department]

PURPOSE

To increase the quality of internal and external interactions (patients, clinical colleagues, technicians, radiologists) in a department of radiology.

METHOD

Accompanied by a well-experienced adviser workshops have been performed dealing with different topics like "contact to patients," "performance of the radiological report and interaction with the referring colleague" or "research and teaching." A catalogue of different actions was defined to reduce hindrances within the internal and external work-flow.

RESULTS

A total number of 53 actions was defined and related to different persons who were responsible for the realisation of the measures within a time interval. Six months after starting the quality management 46 (86%) of the defined actions were realised successfully, and another 4 (8%) measures were still running. There was a moderate increase of satisfaction of the patients and clinical colleagues considering the waiting time.

CONCLUSIONS

A quality management in a radiological department allows an optimisation of the internal and external interactions. However, the guidance of a well-experienced adviser is as essential as the continuous control of successful finished measures.

Classification of hypervascularized lesions in CE MR imaging of the breast

The purpose of this paper is to define and evaluate a classification category for contrast-enhanced (CE) MR imaging of the breast based on the BI-RADS mammographic categories of the American College of Radiology. Using five evaluation criteria for MR findings (initial signal increase, post-initial signal behavior, shape, border, and contrast material distribution within enhancing tumors) 522 patients (1031 breasts) were analyzed. Scores were given from 0 to 8 points and classified into five categories (group I: 0 points, negative; group II: 1-2 points, benign; group III: 3 points, probably benign; group IV: 4-5 points, suspicious abnormality; group V: 6-8 points, highly suspicious for malignancy) to 265 focal hypervascularized breast lesions in 244 breasts (patient group A). These findings were correlated with histology or follow-up. Additionally, this classification was correlated to the contrast medium uptake within the parenchyma of the remaining 787 breasts without any focal lesion (patient group B). Two hundred sixty-five hypervascularized lesions in 238 patients (244 breasts, patient group A) were classified into group I: 0%; group II: 27.3%; group III: 22.3%; group IV: 18.6%; and group V: 31.8%. Histology revealed 115 benign and 134 malignant tumors in these groups. Sixteen benign lesions were controlled by follow-up. Sensitivity for the detection of malignancy using the presented multifactorial MRM classification was 92%, and specificity was 92%. Excluding cases of ductal carcinoma in situ specificity increased to 95%. Seven hundred eighty-seven breasts without any focal hypervascularized lesion (patient group B) were classified into groups I or II. Follow-up ( n=771) or histology ( n=14) confirmed the diagnosis in 785 of these breasts. Histopathology revealed, however, malignant tumors in the remaining two cases. The classification of lesions based on a multifactorial analysis is very helpful in the interpretation of CE MRI of the breast. The evaluation of all diagnostic imaging modalities, however, is essential in determining the correct diagnosis and/or in deciding on the appropriate therapeutic procedure.

Preoperative local MRI-staging of patients with a suspected pancreatic mass

The aim of this study was to define the value of MRI of the pancreas for preoperative local staging of patients with a suspected pancreatic mass. Ninety-four patients (41 women, 53 men; age range 32-87 years) with a suspected pancreatic tumor underwent preoperative staging with MRI on a 1.5-T system. The MRI protocol included breath-hold MR cholangiopancreatography in turbo spin-echo technique, biphasic contrast-enhanced 3D MR angiography, and MRI of the upper abdomen with breath-hold T2-weighted half-Fourier acquired single-shot turbo spin-echo and T1-weighted fast-low-angle-shot (pre- and postcontrast) sequences. Data were collected prospectively and analyzed by two radiologists in agreement modality. Evaluation criteria were vascular involvement, resectability, and a characterization benign vs malignant. Results were compared to histopathology in 78 patients. Sixteen patients were followed-up. In 74 of 94 patients a solid tumor or an inflammation of the pancreas ( n=62) or the papilla ( n=12) was detected. In this group, MRI had a sensitivity of 98%, a specificity of 92%, and an accuracy of 96% in the characterization of malignant tumors. Regarding only the solid tumors, the positive predictive value of MRI was 87% with respect to resectability. Other pathologic findings included adenoma or inflammation of the duodenum ( n=5), carcinoma or benign stenosis of the choledochus duct ( n=7) and carcinoma of the gall bladder ( n=2). In 6 patients MRI did not depict any pathologic findings, and follow-up confirmed this interpretation. Magnetic resonance imaging allows a local preoperative staging in patients with suspected pancreatic tumor. Limitations, however, concern to the diagnostics of peritoneal and/or liver metastases.

Contrast-enhanced MR angiography of abdominal vessels: is there still a role for angiography?

The purpose of this review article is to describe recent advantages in contrast-enhanced (CE) three-dimensional (3D) magnetic resonance angiography (MRA) in comparison with other vascular imaging techniques, and to discuss their current clinical applications for the imaging of abdominal vessels. Principles and technical considerations are presented and clinical applications are reviewed for different vascular diseases. In ruptured aortic aneurysms and acute dissections CT is the method of first choice. Contrast-enhanced 3D MRA can be well used for therapeutic planning and follow-up in patients with stable disease. A comprehensive MR examination including CE 3D MRA, MR urography and MR nephrogram has the potential to replace the conventional studies for the evaluation of renal vascular disease. It is an accurate method for imaging the origins of coeliac and superior mesenteric arteries, although the image resolution is too low for reliable assessment of the inferior mesenteric artery. Contrast-enhanced 3D MRA has emerged as the method of choice for studying the portal venous system in liver transplant recipients, in patients with portal hypertension and in cases with abdominal tumours for preoperative evaluation. Additional non-invasive flow measurements are useful in monitoring portal hypertension. The abdominal veins can be well imaged using unenhanced MR techniques. Imaging may be facilitated with intravascular contrast media. Contrast-enhanced 3D MRA can replace intra-arterial DSA for diagnosis, therapy planning and follow-up in patients with abdominal vascular disease. Catheter-based arteriography will still be used for interventional procedures such as percutaneous transluminal angioplasty, stent placement and embolisation.

[MR-angiography in portal hypertension. State of the art]

When imaging the portal vascular system colour-coded sonography and CT angiography are used as an alternative to intraarterial DSA. Today fast CE 3D-MRA is the imaging modality of choice in the diagnostic of patients with portal hypertension. It enables a clear picture of the portalvenous vascular system and portalsytemic shunts. Statements regarding velocity and direction of blood flow can be made with additional use of TOF and PC techniques. CE-3D MRA can be used preoperatively before liver transplantation or shunt surgery. In the follow-up of interventional or surgical procedures exact statements concerning haemodynamically significant pathologies e.g. vascular thromboses, stenoses and occlusions can be made. Patient consent is symplify and the numbers of complications can be reduced as well as duration of surgery minimized applying this technique.

[Experimental evaluation of vessel diameter from 0.3 to 8 mm in CE MR angiography]

PURPOSE

To evaluate the detection rate of vascular stenosis in contrast-enhanced 3D MR angiography using a flow phantom.

MATERIAL AND METHODS

The examinations were performed on a 1.5 T whole body imaging system (Magnetom Symphony/Quantum) with 30 mT/m gradient field strength using a body-phased-array coil. Different 3D sequences (TR/TE/FA < 5 ms/< 2 ms/25 degrees ) with slice thicknesses ranging from 0.67 to 1.25 mm were applied. A gelantine-filled plastic cylinder with PVC tubes of 8 mm diameter was used as a vascular phantom. The tubes had concentric and excentric stenoses (50 - 90 %) of different lengths. For the detection of different vessel diameters another phantom with 0.3 - 8 mm silicon tubes was used. Both systems were flushed with a solution of Gd-DTPA (0.15 mmol/l) and saline at flow rates from 50 to 200 cm/s. The phantoms were positioned 0 degrees, 45 degrees, and 90 degrees towards the z-axis.

RESULTS

The degree of stenosis was under- and overestimated in less than 10 %. The sequence with the highest spatial resolution provided the best results. Detection and evaluation of tubes >/= 2 mm proved to be reliable.

CONCLUSION

Contrast-enhanced 3D MR angiography provides an almost exact evaluation of the degree of stenosis in the phantom study. Evaluation of vessel diameters < 2 mm is not possible.

[Intramural hematomas of the aorta]

Intramural hematomas (IMH) are regarded as a hemorrhage into the aortic wall. In general a traumatic form can de differentiated from a spontaneous non-traumatic. There is a predisposition of IMH with arterial hypertension and mesoectodermal dysplastic syndromes. The diagnosis is established with the clinical presentation in combination with the findings of different imaging modalities. Acute and subacute discomfort associated with a tendency of collaps are considered as typical presenting complaints. A semicircular or concentric thickening of the aortic wall with the absence of blood flow or a dissection membrane are typical findings in transesophageal echocardiography, computed tomography and magnetic resonance tomography. From a differential diagnostic point of view a distinction from atherosclerotic wall changes, intraluminal thrombi and inflammatory aortic diseases is essential. The IMH is considered as an early presentation of aortic dissection, put into and treated according to the Stanford classification. In the course of natural history an IMH can disappear, rupture or progress into a classic aortic dissection.

[The radial scar in contrast media-enhanced MR mammography]

INTRODUCTION

In patients with the mammographic findings of a radial scar, contrast enhanced (CE) MR mammography was evaluated in a retrospective study.

MATERIAL AND METHODS

In 24 women with radial opacities and black star configurations, CE MR mammography was performed. Examinations were done on a 1.5 T system using bilateral superficial coil (2D technique, T1-weighted FLASH-sequence, TR 336 ms, TE 5 ms, FA 90 degrees). Findings in mammography and MR mammography were compared with the histological results.

RESULTS

15 radial scars (including 4 with additional ADH) and 9 carcinomas (6 in coexistence with a radial scar) presenting with a diameter of 3 mm to 13 mm were evaluated. There was no evidence of malignancy in MRI in 12 of 15 radial scars. In MR mammography 6 of the carcinomas fulfilled the criteria for malignant tumors. There were 3 borderline cases (scored 3 points) corresponding histologically to 1 radial scar, and to 2 carcinomas. Within the results found in MRI there were 2 false positives and 1 false negative.

CONCLUSION

CE MR mammography is superior to other imaging modalities in the differentiation between radial scars and carcinomas. However, lesions suggestive of radial scars have to be removed surgically.

[Stent artifacts in 3D MR angiography: experimental studies]

PURPOSE

The purpose of this phantom study was to evaluate the visualization of vascular stents by using contrast-enhanced (CE) 3D MR angiography (MRA).

METHODS

The measurements were performed on a Magnetom Vision operating at 1.5 T with 25 mT/m gradients by using a head coil; a 3D FISP sequence (TR/TE/FA 4.6 ms/1.8 ms/30 degrees) was used. A phantom was designed with a length of 20 cm and consisted of a plastic cylinder filled with hydrogel. Tubes were used to install 7 different stents (Strecker, Boston Scientific; Cragg, Mintec; Wall, Schneider; Memotherm, Angiomed; St-Come, Trigon-MTS; Sinus, Optimed; Palmaz, Johnson & Johnson) with different metal components. The tubes were perfused with a solution of water and Gd-DTPA. Four radiologists evaluated the image quality. The measurements of the endoluminal stent diameters were compared with the findings obtained by digital subtraction angiography. The signal intensities were measured before (inflow), within (stent) and after (outflow) the different stent types.

RESULTS

The endoluminal diameter of the Cragg stent and the strecker graft were easily detectable. The signal loss within the lumen of the Wall stent was approx. 10% in relation to the inflow and outflow measurements. The result was an only slightly reduced image quality. The other grafts (St-Come, Sinus, Palmaz, Memotherm) showed significant signal losses ranging from 65% to 96%. A correct diagnosis was not possible within these graft lumina.

CONCLUSION

Contrast-enhanced MR angiography can be used to evaluate vascular stents. A prerequisite is the application of particular commercially available grafts.

3D MR angiography of the entire aorta: modified application of the body-phased array coil for a single-shot technique

OBJECTIVE

Evaluation of different contrast-enhanced MR angiography imaging protocols for visualization of the entire aorta in breath-hold technique.

METHODS AND PATIENTS

Three different CE (0.15 mmol/kg) MRA protocols were evaluated by phantom and patient studies: (1) two separate MRA with conventional application of the body-phased array coil; (2) a single-shot MRA with modified application of the body-phased array coil; (3) a single-shot MRA with the body coil. Duplex sonography, CTA and DSA were used as standard of reference.

RESULTS

In all examinations the entire aorta could be visualized. The best SNR was acquired with protocol (1). The SNR of protocol (2) was reduced if the sagittal body diameter of the patient was greater than 20 cm and decreased significantly with diameters over 30 cm. By the use of protocol (3) the SNR was notably poor. The quality scored for the visualization of the entire aorta was 97.5% (protocol 1); 92.5% (protocol 2); and 80.0% (protocol 3).

CONCLUSION

In most cases the modified application of the body-phased array coil allows the imaging of the entire aorta as a single-shot 3D CE MRA in diagnostic quality.

Hepatic blood supply: comparison of optimized dual phase contrast-enhanced three-dimensional MR angiography and digital subtraction angiography

PURPOSE

To optimize and determine the value of dual-phase contrast material-enhanced three-dimensional (3D) magnetic resonance (MR) angiography for preoperative evaluation of the blood supply to the liver.

MATERIALS AND METHODS

Dual phase 3D MR angiography of the hepatic arteries and portal vein was performed in 140 patients. In 80 patients, the value of fat saturation, digital image subtraction, an anticholinergic agent, and a high-caloric meal were evaluated. In the next 60 patients, MR angiographic and digital subtraction angiographic (DSA) image quality and diagnostic value were compared.

RESULTS

Fat-saturated images were of significantly better quality (P < .01) than non-fat-saturated images. Digital image subtraction was useful in only 23 of 40 patients. The injection of an anticholinergic agent was superfluous, whereas administration of a high-caloric meal helped in demonstration of the superior mesenteric artery and portal vein. Classification on MR angiograms of the arterial blood supply was correct in 57 of 60 patients. All arterial and portal venous lesions were seen on MR angiograms, and MR angiograms had a significantly higher subjective image-quality ranking than did DSA images in the evaluation of the portal vein (P < .05).

CONCLUSION

Fat saturation and use of a high-caloric meal improve the results of MR angiography of hepatic vessels. MR angiography was comparable to DSA for evaluation of the arterial system and was superior for demonstration of the portal vein; therefore, MR angiography could replace intraarterial DSA.

Investigation of the imaging properties of an X-ray film scanner

In this note, the imaging properties of a CCD x-ray film scanner were investigated. The relationship between optical density and the logarithm of output pixel value provides information on the linearity of the system. The resolution properties of the scanner can be characterized by the presampling modulation transfer function which was calculated from a set of line spread functions with various alignments relative to the sampling grid. Our results show that the scanner is linear up to 2.0 optical density units, which leads to restrictions in digitizing x-ray films with higher optical density. The measured MTF shows the good spatial resolution of the CCD scanner which is demonstrated on an example.

Arthroscintigraphy in suspected rotator cuff rupture

AIM

In order to evaluate the diagnostic efficiency of arthroscintigraphy in suspected rotator cuff ruptures this new imaging procedure was performed 20 times in 17 patients with clinical signs of a rotator cuff lesion. The scintigraphic results were compared with sonography (n = 20), contrast arthrography (n = 20) and arthroscopy (n = 10) of the shoulder joint.

METHODS

After performing a standard bone scintigraphy with intravenous application of 300 MBq 99m-Tc-methylene diphosphonate (MDP) for landmarking of the shoulder region arthroscintigraphy was performed after an intraarticular injection of 99m-Tc microcolloid (ALBU-RES 400 MicroCi/5 ml). The application was performed either in direct combination with contrast arthrography (n = 10) or ultrasound conducted mixed with a local anesthetic (n = 10). Findings at arthroscopical surgery (n = 10) were used as the gold standard.

RESULTS

In case of complete rotator cuff rupture (n = 5), arthroscintigraphy and radiographic arthrography were identical in 5/5. In one patient with advanced degenerative alterations of the shoulder joint radiographic arthrography incorrectly showed a complete rupture which was not seen by arthroscintigraphy and endoscopy. In 3 patients with incomplete rupture, 2/3 results were consistent. A difference was seen in one patient with a rotator cuff, that has been already revised in the past and that suffered of capsulitis and calcification.

CONCLUSION

Arthroscintigraphy is a sensitive technique for detection of rotator cuff ruptures. Because of the lower viscosity of the active compound, small ruptures can be easily detected, offering additional value over radiographic arthrography and ultrasound, especially for evaluation of incomplete cuff ruptures.

[Determination of contour clarity in contrast-enhanced MR angiography: definition and clinical evaluation exemplified by ECG-triggered imaging of the thoracic aorta]

PURPOSE

The sharpness of the vessel contour in 3D contrast-enhanced MR angiography is defined by particular measurements of the signal intensity. To evaluate the facilities of an ECG-triggered data acquisition to optimize the MRA image quality of the thoracic aorta.

METHOD

In phantom studies the sharpness of the vessel contour was defined as the distance of the extraluminal signal-minimum to the extraluminal maximum. Afterwards 30 examinations of the thoracic aorta with and without the use of an ECG-triggering were evaluated with regard to the sharpness of the vessel outline.

RESULTS

The presented definition of the signal intensity is suitable for objective measurements of the vessel outline. At the level of the ascending aorta, ECG-triggered data acquisition increased the image quality significantly.

CONCLUSIONS

An easy, practicable definition enables measurements of the sharpness of the vessel outline. ECG-triggered data acquisition is recommended for optimal visualization, especially of the ascending aorta.

Electrocardiograph-triggered two-dimensional time-of-flight versus optimized contrast-enhanced three-dimensional MR angiography of the peripheral arteries

We determined whether the accuracy of magnetic resonance angiography (MRA) in the peripheral run-off vessels can be improved by using contrast-enhanced (CE) three-dimensional (3D) technique in comparison to electrocardiograph (ECG)-triggered two-dimensional (2D) time-of-flight (TOF) technique. In a prospective study 20 patients with occlusions of the pelvic and/or femoral arteries underwent a CE 3D MRA (repetition time (TR): 5 ms, (TE) echo time: 2 ms, flip angle (FA): 30 degrees ) and an ECG-triggered 2D time-of-flight (TOF) technique (TR: 408 resp. 608 ms, TE: 7 ms, FA: 70 degrees) of the run-off vessels on a 1.5 T MR system. Each patient received a contrast material volume of 0.15 mmol/kg of body weight of gadolinium (Gd)/DTPA using an automatic injector. The tube system to the patient was flushed by 50 mL of a saline solution applied with the same injection rate as the contrast material administration. The start of the 3D MR sequence was tailored individually to the applied contrast material after determination of circulation times by a prior bolus. All patients underwent each conventional or digital arteriography for comparison, as well. The visualization of the run-off vessels was ranked on a scale of 0-3 (0 = poor, 1 = fair, 2 = good, 3 = excellent) by three blinded reviewers. They also graded the vascular segments as either occluded or significantly altered (>50% reduction in diameter) or free of significant stenosis. CE 3D MRA was significantly faster in imaging the run-off vessels in comparison to the ECG-triggered 2D TOF technique. All 160 vascular segments were visualized with the 3D method, whereas only 142/160 segments were seen with 2D technique. The resulting image quality ranking of all vascular segments was significantly higher (p < 0.05) using CE 3D MRA (2.8) than with the 2D TOF technique (2.4). The detection of the stenoses was possible with both techniques. The grading of seven of seven stenoses was correct with 3D method and in five of seven cases with the 2D TOF technique. All vessel occlusions were detected by using both techniques. Small collaterals were visualized in more detail with the CE 3D MR angiography. These data demonstrate an improvement in image quality and accuracy of MRA of the peripheral arteries using a CE 3D technique in comparison to an ECG-triggered 2D TOF sequence.

Differences in injection rates on contrast-enhanced breath-hold three-dimensional MR angiography

OBJECTIVE

The aim of the study was to evaluate the optimization of injection rates with an automatic power injector versus manual injection for contrast-enhanced breath-hold three-dimensional (3D) MR angiography of the abdominal aorta and its branches.

SUBJECTS AND METHODS

In a prospective study, 50 patients underwent breath-hold 3D MR angiography (5/2 [TR/TE]; flip angle, 30 degrees) of the abdominal vessels on a 1.5-T system. Each patient received 0.15 mmol/kg of gadopentetate dimeglumine. All patients were randomly assigned to one of five equally sized groups. The contrast bolus was injected manually in group 1, always by the same investigator, who tried to perform a steady injection rate of 2 ml/sec. An automatic injector was used in groups 2-5 with injection flow rates of 0.5 ml/sec, 2 ml/sec, 4 ml/sec, and 6 ml/sec. The start of the MR sequence was tailored individually to the applied volume of contrast material after determination of circulation times by a test bolus. We measured the signal-to-noise and contrast-to-noise ratios as well as the relative vascular enhancement. The visualization of different abdominal vessel segments was independently ranked on a scale of 1-5 (1 = not visible; 5 = excellent visualization) by three reviewers who were unaware of the applied contrast material injection rate.

RESULTS

The signal-to-noise and contrast-to-noise ratios of groups 3 and 4 (2 ml/sec and 4 ml/sec, respectively) were significantly (p < .05) higher than the ratios of groups 1, 2, and 5. The average relative vascular enhancement of groups 3 and 4 was significantly higher (p < .05) than the enhancement of all other groups. The contrast bolus applied with a faster injection rate (group 5) did not cover large parts of the K-space, resulting in increased blurring of the vessel contours. The subjective evaluation of large and small diameter vessels showed significantly better results in groups 3 and 4 than in groups 1, 2, and 5.

CONCLUSION

The use of an automatic MR power injector proved superior to manual injection of contrast material. The optimal injection rate was 2 ml/sec for 3D breath-hold MR angiography of the abdominal vessels.

[Contrast media-enhanced 3D MR angiography of the peripheral vessels using a "tracking technique": preliminary results]

PURPOSE

A single bolus contrast-enhanced (CE) 3D MR angiography (MRA) of the peripheral vessels was evaluated using a combination of two surface coils with manual incrementation of the patient table.

METHODS

Fifteen patients with peripheral arterial occlusive disease were examined using an ultrafast CE 3D MRA (TR/ TE/FA 5 ms/2 ms/30 degrees). For imaging of the vessels from the distal aorta to the arteries of the lower limbs a combination of a body-array coil and a flexible extremity coil was applied. A coil-interface was designed for a connection of the two coils. The examinations were performed after a single bolus of 0.15 mmol Gd-DTPA/kg. The tracking technique included a manual incrementation of the patient table and the coil-interface had to be switched from the body-array coil to the flexible extremity coil. For acquisition delay measurement of the MR sequence the individual transit times of the contrast material were detected by using a test bolus.

RESULTS

CE 3D MRA was technically successful in 14/15 cases. In one case two vascular segments were not imaged. The qualitative evaluation of all vascular segments documented a high quality without any significant differences between the proximal and the distal arteries (p < 0.05). All hemodynamically significant stenoses (n = 15) and all vessel occlusions (n = 36) were detected.

CONCLUSION

The single bolus CE 3D MRA using a tracking technique is a favourable method in the evaluation of patients with peripheral arterial occlusive disease.

[Case report of a large lipomatous soft tissue tumor]

A case of diffuse infiltrating lipomatosis is reported. This entity represents a particular type of lipoma. It can be distinguished from other fatty tumors by its localisation, extent, therapeutic procedure, and prognosis. Magnetic resonance imaging (MRI) enables the differentiation from lipomatosis pelvis and malignant tumors as well. Histopathological examination, however, is necessary to exclude liposarcoma. Further growth or recurrence of diffuse infiltrating lipomatosis can be detected by MRI follow-up examinations.

[Contrast medium enhanced MR angiography of peripheral blood vessels]

Currently 2D time-of-flight MR angiography (MRA) is most commonly used for the evaluation of the extremities. The major limitation is their susceptibility to signal loss from intravoxel phase dispersion. This leads to overestimation in the grading of stenoses. Further difficulties are motion artifacts and the limited spatial resolution. Phase-contrast MRA is increasingly used. However, further studies are required to verify its diagnostic potential. MRA technology continues to advance rapidly. Stronger gradient fields, shorter echo times and high resolution surface coils are developed. Contrast medium can be applied under standardized conditions with MR compatible power injectors. In phantom studies, the contrast-enhanced gradient echo sequences show reduced phase dispersion, resulting in an improved grading of stenoses. Initial patient studies underline these findings. Contrast-enhanced MR angiography has the potential to replace invasive arteriography in the evaluation of peripheral arterial vessels in the near future.

[Results of a contrast-medium supported 3D MR-angiography in respiratory arrest following optimization of contrast medium bolus]

PURPOSE

Reduction of the contrast material volume by optimised bolus administration during a breath-hold 3D MR angiography and its clinical value.

MATERIALS AND METHODS

Breath-hold ultrafast 3D gadolinium-enhanced MR angiography (TR 5 ms, TE 2 ms, FA 20 degrees) of the thoracic and abdominal aorta was performed in 50 patients and correlated with an i.a. DSA. 25 patients (group 1) were examined with a contrast material volume of 40 ml Gd-DTPA and three successive acquisitions at fixed intervals (25, 53 and 81 s) after start of the contrast material injection. Another group of 25 patients (group 2) received only 20 ml Gd-DTPA and the start of the MR acquisition was determined individually by prior evaluation of the contrast material transit times after injection of a test bolus. The signal-to-noise (S/N) and contrast-to-noise (C/N) ratios were compared and a subjective image quality rating (0-3) by three reviewers was achieved in both groups.

RESULTS

A total of 37 vascular pathologies were correctly detected by MR angiography compared to i.a. DSA. The grading of stenoses was overestimated in some cases. The S/N and C/N were higher in group 2 (63.2 and 50.1) than in group 1 (58.0 and 38.9). The subjective ratings also showed better results in group 2 (2.76) than in group 1 (2.20).

CONCLUSION

The ultrafast gadolinium-enhanced 3D MR angiography allowed a reliable visualisation of the thoracic and abdominal aorta and its branches in a single breath-hold. An optimised examination with a reduced contrast material volume can be achieved by an individual adaptation of the MR acquisition to contrast material administration after measurement of the contrast material transit times.

Sexual dysfunction in Peyronie's disease: an analysis of 222 patients without previous local plaque therapy

PURPOSE

We obtained an objective evaluation of erectile function in patients with Peyronie's disease.

MATERIALS AND METHODS

Sexual dysfunction was analyzed in 222 patients with Peyronie's disease without previous local plaque therapy using a standardized protocol.

RESULTS

Of the 222 patients 70 (31.5%) complained of not being able to perform intercourse. In 4 men (1.8%) standardized diagnostic procedure demonstrated only a severe angulation making coitus impossible, and in 3 men (1.4%) intercourse became unsatisfactory due to pain. Seven men (3.1%) reported distal penile flaccidity, including 4 in whom dynamic pharmacocavernosometry and pharmacocavernosography revealed veno-occlusive dysfunction. Of 56 men who complained of a complete loss of erection 51 did not respond to intracavernous pharmacological injection with prostaglandin E1, and 27 (48.2%) had abnormal arterial blood flow as shown by duplex sonography of the cavernous arteries, 47 (83.9%) had evidence of veno-occlusive dysfunction based on cavernosometric criteria and 33 (58.9%) also had cavernosographic evidence of the condition. Plaque associated venous drainage was evident in 15 of the 56 impotent patients (26.8%), equivalent to 45.5% of all cases with abnormal cavernosographic findings.

CONCLUSIONS

Sexual dysfunction was evaluable in 31.5% of patients, and the main cause of impotence and loss of erection was veno-occlusive dysfunction.

[MR angiography of the pelvic-leg blood vessels: current status and perspectives]

Currently 2D time-of-flight (TOF) MR angiography (MRA) is most commonly used for the evaluation of the extremities. The major limitation of all MRA techniques is their susceptibility to signal loss from intra-voxel phase dispersion. This leads to an overestimated grading of the stenosis. Further difficulties are motion artifacts and the limited spatial resolution. Therefore, MRA alone cannot be used routinely as a preoperative diagnostic procedure in patients with peripheral arterial disease. The postoperative examination of patients with vascular bypasses, however, seems to be a practical application of this technique. It is also possible to use MRA to image the lower limbs after percutaneous interventional angioplasty. The application of 2D-ECG-triggered sequences or the current fast technique of contrast-enhanced 3D-TOF MRA might play a role in combination with surface coils for future examinations of peripheral arterial disease.

MR arthrography in the diagnosis of rotator cuff tears. Standard spin-echo alone or with fat suppression?

PURPOSE

To examine the value of fat-suppressed images in MR arthrography of the shoulder in patients with rotator cuff tears.

MATERIAL AND METHODS

MR arthrography was performed in 25 patients (9 women, 16 men) ranging from 19 to 64 years. Standard T1-weighted spin-echo images (sSE) and fat-suppressed images (FS) were obtained after intraarticular injection of contrast material. The MR studies were analyzed according to contrast, image quality and conspicuity of pathology. A diagnosis was established without knowledge of the conventional arthrographic findings on the basis of sSE versus FS techniques.

RESULTS

The contrast between the intraarticular fluid and the adjacent structures in FS images was increased compared to sSE images in all patients. The conspicuity of anatomical structures was improved in 8 patients. Without fat suppression, 2 false-negative and one false-positive full-thickness tears were diagnosed. With the FS technique, 14 full-thickness tears and 4 partial-thickness tears of the cuff were correctly classified.

CONCLUSION

The results suggest that, if MR arthrography is chosen for a diagnosis of rotator cuff disorders, a fat suppression sequence should be included.