[Evaluation of an electromagnetic virtual target system (CT-guide) for CT-guided interventions]

PURPOSE

Evaluation of the accuracy of a new electromagnetic target system for interventional CT-guided procedures with virtual navigation in a previously acquired helical CT.

MATERIAL AND METHODS

The new target system CT-Guide 1010 (Ultraguide, Tirat Hacarmel, Israel) for CT-guided interventions was adapted to the video signal of the Somatom Plus 4 and Volume Zoom (Siemens, Erlangen, Germany). A helical CT-dataset including skin-based sensor cubes was transferred to the integrated navigation system inside the scanner room. 50 image-guided interventions and biopsies were performed outside the gantry using virtual navigation to reach the lesion. The accuracy of the procedures was evaluated using documentation of the needle tip with CT-fluoroscopy, results of histology, and follow-up.

RESULTS

The deviation between planned and documented needle tip was 2.2 +/- 2.1 mm in 50 procedures. Time between the end of planning-CT and needle positioning using the system was 13 minutes. There were no complications due to the use of the system.

CONCLUSION

The CT-Guide allows for virtual real-time navigation with high accuracy. Advantages are the free needle angulation without gantry tilt, use of optimal CT perfusion phase for virtual navigation, and reduction of radiation exposure to the patient and interventionalist.

Extracorporeal shock-wave therapy for chronic lateral tennis elbow--prediction of outcome by imaging

Today the clinical use of extracorporeal shockwave application (ESWA) for the treatment of lateral tennis elbow is hampered by the lack of results from randomized controlled trials and of predictive parameters of clinical outcome. The present prospective study aimed to provide the latter by means of magnetic resonance imaging (MRI). Twenty-three female and 19 male patients with unilateral chronic tennis elbow of the dominant site were clinically examined before and after repetitive low-energy ESWA. MRI was performed before ESWA to evaluate signal intensity changes or contrast enhancement of the common extensor tendon and the lateral epicondyle. After ESWA (mean follow-up period 18.6 months for all patients), clinical evaluation showed a significantly better mean clinical performance after ESWA than before treatment. Interestingly, male patients showed a significantly better mean clinical performance after ESWA than female patients, and male and female patients differed significantly in the signal intensity of the common extension tendon cross-section and tendon thickening on MRI. For female patients, MRI scans could be applied for predicting a positive clinical outcome of ESWA. This study reports the first indication of predictability of positive clinical outcome of the treatment of chronic lateral tennis elbow by ESWA using imaging prior to treatment. This may serve as an important step towards overcoming the therapeutic nihilism with respect to the non-operative management of this condition recently in the literature.

[Benign bone-forming tumors]

Benign bone-forming tumors include osteomas, enostomas, osteoid osteomas, and osteoblastomas. These lesions are often characterized by typical imaging findings on radiographs, CT and MR imaging studies. Radiologic findings and additional clinical information allow for a specific diagnosis in most cases. This review article emphasizes the radiological patterns of benign bone-forming tumors as well as their epidemiological, clinical, and pathological characteristics. In addition, minimally invasive interventional procedures for the therapy of osteoid osteoma are reviewed.

Shockwave application in calcifying tendinitis of the shoulder--prediction of outcome by imaging

This prospective study examined 62 patients (65 shoulders) with chronic courses of calcifying tendinitis of the shoulder before and after low-energy extracorporeal shockwave application (ESWA) in order to identify variables associated with the outcome of this treatment. Before ESWA, radiographs and contrast-enhanced magnetic resonance imaging (MRI) of the affected shoulders were obtained in order to document the size and morphology of the calcifications and the contrast media reactions in areas of interest (deposit, synovia, bursae), respectively. In addition, a clinical evaluation was performed. After ESWA (mean follow-up 18.2 months), clinical evaluations of all 65 shoulders revealed an increase in the Constant score from 44% to 78% (p < 0.0001). While size (p = 0.61) and morphology (p = 0.7) of the deposits before ESWA were not associated with the clinical outcome, negative contrast reactions around the deposits (p) = 0.0001), synovia (p = 0.0049) and bursae (p < 0.01) were associated with improved clinical outcomes. After the total study group was divided into two groups, one with Constant scores > or = 75% (n = 43) and the other with scores < 75% (n = 22), the positive predictive value (ppv), specificity (sp) and sensitivity (se) were determined for the negative reaction around the deposit (ppv: 0.94; sp: 0.95; se: 0.38), synovia (ppv: 0.84; sp: 0.82; se: 0.49) and bursae (ppv: 0.86; sp: 0.86; se: 0.44). In 5 cases (7.7%), surgery of the affected shoulder during the follow-up period was performed. No major side-effects were seen in the study group. In conclusion, our results suggest that in patients with chronic calcifying tendinitis, the absence of contrast enhancement, especially around the deposit, is a strong predictive parameter of a positive clinical outcome of ESWA.

Imaging of spinal infection

MR imaging is the modality of choice for the detection, staging, and differential diagnosis of inflammatory disorders of the spine. Infectious spondylitis is characterized by the involvement of two adjacent vertebrae and the intervening disk with severe BME and early destruction of the end plates. The disk space is narrowed and typically exhibits water-equivalent signal intensity on T2-weighted or STIR images. Prevertebral and epidural extensions, abscess formation, enhancement of the BME, the disk space, and the surrounding granulation tissue are well demonstrated by gadolinium-enhanced images. Cervical spondylitis frequently involves more than one level. Bone marrow abnormalities may be subtle at this level and increased signal intensity of the disk space on T2-weighted or STIR images is an important finding. The risk for neurologic complications is increased. Granulomatous infections caused by tuberculosis, brucellosis, fungi, and parasites, including hydatid disease (Echinococcus), are frequently associated with imaging findings different from those seen with nonspecific bacterial infection. In patients with chronic infectious spondylitis, diffuse reactive bone marrow changes with decreased signal intensity on T1-weighted images, increased signal intensity on T2-weighted and STIR images, and increased uptake after gadolinium administration may occur. This phenomenon is probably caused by reactive bone marrow stimulation, simulating diffuse hematologic neoplastic disease. Erosive intervertebral osteochondrosis with bandlike disk gadolinium enhancement and BME, which is commonly associated with local pain, is the most important differential diagnosis of bacterial spondylitis.

[Radiofrequency ablation of liver metastases. Technique and initial results]

Primary and secondary malignant hepatic tumors are the most common tumors with a much more higher incidence of hepatic metastases. Chemotherapy and radiation therapy are in general ineffective. Therefore, surgical resection is considered the method of choice in the treatment of malignant hepatic lesions. Due to systemic disease, general medical or procedure-related reasons hindering surgery, only 25 to 45% of the patients with metastatic disease of the liver are suitable for a curative surgical therapy. In resectable lesions thermoablative methods can offer an alternative to the surgical therapy. The most experience exists in radiofrequency ablation techniques. Technique, indications, contraindications, and limitations of the radiofrequency ablation will be discussed together with a presentation of own cases and a review of the literature. In 37 patients the primary technical success rate of the ablation was 97.3% (72 of 74 lesions). In 4 cases a hematoma of the liver capsule occurred. One of these had to be treated interventionally. During the limited follow-up period of 9 months no local recurrency was seen, however 4 patients developed new hepatic metastases. Beside differences in practicability it is not yet clarified if there are differences in the therapeutic efficacy of the different thermoablation methods. Nevertheless, the results of the ablation therapy may parallel the results of the surgical resection. Interstitial thermotherapy can provide a valuable contribution to local tumor control. However, the final significance of the thermoablation techniques within oncological therapy regimens has to be evaluated in further multidisciplinary studies.

Reactive bone marrow changes in infectious spondylitis: quantitative assessment with MR imaging

PURPOSE

To evaluate diffuse, reactive bone marrow changes in unaffected vertebrae on magnetic resonance (MR) images in patients with proved infectious spondylitis.

MATERIALS AND METHODS

Percentage signal intensity increase of the unaffected bone marrow on contrast material-enhanced MR images (percentage enhancement) was calculated retrospectively in 22 cases of infectious spondylitis and 86 cases without bone marrow disease. Multiple regression analysis and Student t test statistics were performed.

RESULTS

Multiple regression analysis showed a significant influence of age and the presence of spondylitis on the values of percentage enhancement (P: <.001). For those aged 35 years or younger, the mean percentage enhancement was 43.2% +/- 4.0 for patients with infectious spondylitis (n = 3) and was 26.4% +/- 8.6 for the control group (n = 23). For those older than 35 years, the mean percentage enhancement was 28.2% +/- 12.2 for patients with infectious spondylitis (n = 19) and 17.5% +/- 7.9 (P: <.001) for the control group (n = 63). Six (27%) of 22 patients with infectious spondylitis showed abnormal percentage enhancement values in unaffected bone marrow when the upper limit of the normal value was 2 SDs above the mean of the control group.

CONCLUSION

On MR images, reactive bone marrow changes can be found in unaffected vertebrae in patients with infectious spondylitis. The signal intensity changes and increased percentage enhancement associated with this disease are similar to those of myeloproliferative and diffuse neoplastic disorders and bone marrow stimulation in hemolytic anemia.

Extracorporeal shock wave application for chronic plantar fasciitis associated with heel spurs: prediction of outcome by magnetic resonance imaging

OBJECTIVE

To clarify morphologic features associated with the clinical outcome of extracorporeal shock wave application (ESWA) in chronic plantar fasciitis.

METHODS

In this prospective study 43 patients (48 heels) with chronic courses of plantar fasciitis were clinically examined before and after repetitive low energy ESWA. Standard radiographs of the affected heels were obtained before ESWA to document the existence of a calcaneal heel spur. Magnetic resonance imaging (MRI) was performed before ESWA to evaluate abnormalities of the plantar fascia, the surrounding soft tissue structures, and bone marrow edema of the calcaneus.

RESULTS

After ESWA (mean followup 19.3 mo), clinical evaluation of all 48 heels revealed a statistically significant decrease in the mean visual analog scale score from 74.5 to 25.4. Using the Roles and Maudsley score (RM), an established scoring system for categorizing results of treatment following ESWA for patients with plantar fasciitis, patients could be divided into 2 groups, i.e., satisfactory clinical outcome of ESWA (grades 1 and 2 by RM scale; n = 36 heels) and unsatisfactory outcome (grades 3 and 4 by RM scale; n = 12 heels). While thickness of plantar aponeurosis, soft tissue signal intensity changes, and soft tissue contrast medium uptake did not correlate with clinical outcome, the presence of a calcaneal bone marrow edema was highly predictive for satisfactory clinical outcome (positive predictive value 0.94, sensitivity 0.89, specificity 0.8).

CONCLUSION

This study indicates that in patients with chronic plantar fasciitis, the presence of calcaneal bone marrow edema on pretherapeutic MRI is a good predictive variable for a satisfactory clinical outcome of ESWA.

[The diagnosis of metastases in the bone marrow by MRT]

MRI plays an important role in the diagnostic workup of skeletal metastases. In principle two different applications of MRI can be distinguished: apart from the well known indications of clarifying uncertain lesions seen with other imaging modalities or demonstrating known osseous lesions with high resolution imaging for therapeutic planing, MRI can also be used as a primary screening modality for skeletal metastases. Besides the higher lesion detection rate the major advantage of MRI compared to bone scintigraphy lies in the demonstration of morphology which on the one hand exactly shows the extension of tumorous lesions and on the other hand clearly distinguishes between malign and benign processes. As unclear findings on bone scintigraphy often require additional imaging studies, especially in patients with clinical findings or lab results suggestive for metastatic disease, we think that whole-body-skeletal-MRI is not only an accurate but also a cost effective diagnostic modality in the detection and screening for skeletal metastases, if the indication for the examination is closely related to clinical findings and the therapeutic relevance of the imaging results.

Partial rupture of the distal biceps tendon

Partial rupture of the distal biceps tendon is a relatively rare event, and various degrees of partial tendon tears have been reported. In the current study four patients with partial atraumatic distal biceps tendon tears (mean age, 59 years; range, 40-82 years) are reported. In all four patients, a common clinical pattern emerged. Pain at the insertion of the distal biceps tendon in the radius unrelated to any traumatic event was the main symptom. In all patients the diagnosis was based on magnetic resonance imaging or computed tomography imaging. In three of four patients the partial rupture of the tendon caused a significant bursalike lesion. The typical appearance was a partially ruptured biceps tendon, with contrast enhancement signaling the degree of degeneration, tenosynovitis, and soft tissue swelling extending along the tendon semicircular to the proximal radius. In three patients, conservative treatment was successful. Only one patient needed surgery, with reinsertion of the tendon resulting in total functional recovery.

Musculoskeletal MR: knee

Magnetic resonance imaging is the most sensitive, specific, and accurate noninvasive method for diagnosing internal derangement of the knee. During the past 15 years knowledge of pathologic conditions of the knee had evolved significantly. Beyond the basic principles of imaging knee injuries great impact was made on the understanding of indirect or collateral findings, even in rare diseases. In this article the spectrum of disorders of the knee are reviewed and an overview of the current literature is given. This includes considerations about how to achieve a high-standard MR imaging study of the knee, and principles of imaging anterior cruciate ligament and meniscal tears. A focus is put on distinct diseases including intra-articular and intraosseous ganglion cysts, iliotibial band friction syndrome, transient osteoporosis, osteonecrosis, osteochondritis dissecans, and imaging of the articular cartilage.

[Magnetic resonance imaging of the wrist--comparison of high resolution pulse sequences and different fat signal suppression techniques in cadavers]

PURPOSE

To evaluate high resolution sequences with and without fat-suppression techniques for MR imaging of the wrist.

MATERIALS AND METHODS

10 cadaver wrist specimens were imaged with 12 MR sequences (SE: 400 ms/20 ms, TSE: 3000 ms/119 ms/17 ms, fatsat (FS) TSE: 3000 ms/17 ms and 3000 ms/45 ms, STIR: 2619 ms/29 ms/160 ms, DESS 3D: 43.7 ms/9 ms/35 degrees FS and 25.4 ms/9 ms/35 degrees water excitation (WE), CISS 3D: 12.2 ms/5.9 ms/40 degrees and FLASH-sequences: 53 ms/11 ms/40 degrees FS, 23 ms/11 ms/40 degrees WE and 45 ms/11 ms/30 degrees FS) at 1.5 T. Slice thickness was 3 mm, FOV 80 x 70 mm (pixel size 0.31 x 0.31 mm). Signal intensity was measured by an ROI in bone marrow, fluid, hyaline cartilage, scapholunate (SL) ligament and triangular fibrocartilage and S/N- and C/N-ratios were calculated. Additionally, a visual evaluation was performed.

RESULTS

The highest homogeneity and the least artifacts were achieved by the T1-w SE sequence. For the STIR and PD-FS TSE sequence high rankings were found for the detection of free water. The PD FS sequence had high ranking also for visualization of the SL ligament and the triangular fibrocartilage. The best sequence for the assessment of hyaline cartilage was the FLASH-FS sequence. For detailed analysis of bony structures the CISS sequence performed best.

CONCLUSION

The isolated use of a PD-FS-TSE sequence enables for evaluation of all clinically relevant structures at the wrist. Dedicated questions for hyaline cartilage are answered best by the use of a FLASH 3D-FS sequence. Selective water excitation reduces acquisition time to 60%, nevertheless FS sequences are still diagnostically superior to WE sequences.

[Spondylolysis in the developmental stage: diagnostic contribution of MRI]

PURPOSE

To assess the value of MR imaging in demonstrating ongoing spondylolysis in adolescents.

METHODS

MRI was performed in 9 juvenile patients (3 female, 6 male aged 8-16 years; mean 12.5 y) with pain during hyperextension. In 6 patients a CT scan and in 5 a plain film was available.

RESULTS

In all patients bone marrow edema was found in the pars interarticularis and the pedicle, which was bilateral in 4 patients. In 7/9 cases the L5 vertebra was affected, in 2/9 cases spondylolysis was found in L4. In 3 cases the edema reached the middle third of the vertebral body and a tumor was suspected. In all CT scans a bilateral incomplete or complete cleft in the pars inter-articularis was found. In 4/6 CT-scans a sclerosis was seen in the area of the bone marrow edema. Only in 1/5 plain films was there a suspicion for a spondylolysis, four examinations were completely normal.

CONCLUSIONS

To eliminate underlying causal conditions of spondylolysis and to install specific therapy, early diagnosis is mandatory. MR imaging should be the first and only imaging modality in young patients with low back pain during and after exercise and pain with hyperextension. Bone scans and CT scans should be avoided due to irradiation, plain films usually do not reveal pathological findings in developing sponylolysis.

Intravertebral vacuum phenomenon following fractures: CT study on frequency and etiology

PURPOSE

The purpose of this work was to determine the frequency and etiology of the intravertebral vacuum phenomenon (IVP).

METHOD

CT examinations of 96 vertebral fractures were evaluated for IVP. Bone mineral density (BMD) was determined in nonfractured vertebrae. For calibration purposes, densities of a standard phantom measured in 30 patients who underwent quantitative CT examinations in the same time period were used and precision was calculated.

RESULTS

Eleven of 96 fractures (11.5%) showed IVP. IVP was present in 4 of 20 fractures at T12 (20%), in 4 of 23 at L1 (17.4%), and 1 IVP was found at L2-4 each. Mean +/- SD age of patients with IVP was 68.3 +/- 10.5 years and without 47.8 +/- 19.4 years (p < 0.001). Mean +/- SD density of nonaffected vertebra was 45.9 +/- 17.0 mg of hydroxyapatite/ml for patients with IVP and 139.5 +/- 62.6 mg/ml for those without IVP (p < 0.0005). An average precision of 1.2% was calculated for the density measurements over the investigated time.

CONCLUSION

Following vertebral fractures, IVP on CT scans is more common than presumed and increases with age. There exists a significant inverse correlation between the BMD and the frequency of IVP.

Symptomatic fibrous lunato-triquetral coalition

In general, carpal coalitions are considered to be asymptomatic. Incomplete separated joints and associated changes similar to osteoarthritis and pseudoarthrosis are known as possible causes of wrist pain. We present the clinical history, plain-film, and MR imaging findings of two patients with symptomatic fibrous lunato-triquetral coalition. Conventional films disclosed a narrowed space between the lunate and triquetral bone with cysts and sclerosis similar to pseudoarthrosis. Magnetic resonance imaging showed bone marrow edema adjacent to the incomplete separated lunato-triquetral joint and Gd-DTPA enhancing fibrovascular tissue in the synovium and subarticular cysts, explaining the pain over the ulnar-sided wrist. Patients with congenital lunato-triquetral coalition may poorly tolerate stress loading or trauma, resulting in a symptomatic state similar to degenerative arthritis or pseudoarthrosis, which is demonstrated by enhanced MR imaging.

[Pseudoaneurysm of the lingual artery after tonsillectomy. A rare complication]

BACKGROUND

Tonsillectomy is one of the most common surgical procedures in otorhinolaryngology; however, life-threatening complications can occur in rare cases.

PATIENTS

We report about a seven-year-old girl who developed a pseudoaneurysm of the lingual artery following elective routine tonsillectomy.

RESULTS AND CONCLUSION

Initial ENT examination will reveal a painful cervical mass or unilateral palatal swelling that can easily be misinterpreted as a peritonsillar (or parapharyngeal) abscess. Computed tomography and angiography are indicated to confirm the diagnosis. Bleeding from a pseudoaneurysm of any branch of the external carotid artery represents a serious and life-threatening complication. Surgery is the treatment of choice.

[Reliability of functional x-ray analysis of cervical vertebrae flexion and extension]

Functional radiographic analysis of the cervical spine in flexion and extension position is increasingly used as screening method for the diagnosis of segmental functional disorders. The objective of this study was to prove Penning's evaluation method for the metrical recording of segmental angles in the sagittal plane for selectivity, reliability and usability. Passive functional radiographs of the cervical spine in flexion and extension were taken of 20 patients with painful limitation of mobility of the cervical spine and 20 subjects, similar in sex and age, without complaints. The radiographs were duplicated. Five physicians measured the angles of segmental mobility in a blind study. Statistical analysis was conducted using the t-test and calculating the correlation coefficient "r". The results of the study prove that the evaluation method by Penning shows a usable and, for segments C3/C4 to C6/C7, significant selectivity. The selectivity of p < or = 0.05 and p < or = 0.01 is sufficient to distinguish patients from healthy subjects. The correlation between the five reviewers showed good to very good results (0.6 < r < or = 0.8; r > 0.8). The measured values, however, have to be considered, in connection with the appropriate clinical symptoms, as still "normal" or "functionally disordered" in the context of segmental hypo-resp. hypermobility.

[Evaluation of right heart load with spiral CT in patients with acute lung embolism]

PURPOSE

Purpose of this study was to evaluate whether spiral-CT allows judgment of right ventricular failure in patients with acute pulmonary embolism.

MATERIALS AND METHODS

61 patients underwent spiral-CT due to suspicion of acute pulmonary embolism. Patients with pulmonary embolism were divided into subpopulations according to the severity of pulmonary embolism in the CT scan. Cardiac measurements were performed on axial spiral-CT images and compared to those of patients without suspicion of pulmonary embolism or cardiac diseases.

RESULTS

In 30 patients spiral-CT revealed acute pulmonary embolism. Significant differences in cardiac measurements in patients with severe and less severe pulmonary embolism were found on comparing the following dimensions: left ventricular width (p = 0.0003), left (p = 0.008) and right (p = 0.009) ventricular cross-sectional area, proportion of right to left ventricular width (p = 0.0003) and proportion of right to left ventricular cross-sectional area (p = 0.0001). The proportion of the cross-sectional areas (r = 0.65) and the proportion of the width (r = 0.60) of both ventricles correlated well with the severity of central pulmonary embolism.

CONCLUSION

Besides reliable assessment of pulmonary embolism spiral-CT allows the evaluation of cardiac dimensions for judgment of right ventricular failure.

MRI findings of muscle involvement in idiopathic hypereosinophilic syndrome

A 40-year-old white man presented with fever, muscle pain, skin nodules and persistent hypereosinophilia over a period of 1 year. In addition, he had ventricular arrhythmias with episodes of tachycardia. Besides a lack of response to antiparasitic therapy, laboratory and pathological data excluded the diagnosis of trichinosis or any other parasitic infection. The patient's course of the disease over the previous 1(1)/2 years was compatible with hypereosinophilic syndrome. In a muscle biopsy several eosinophilic perivascular and leucocytic intravascular infiltrates were found, indicative of muscle involvement by the disease. This is a report on the MRI findings of muscle involvement in idiopathic hypereosinophilic syndrome.

Erdheim-Chester disease: a case report and literature overview

Erdheim-Chester (EC) disease belongs to the group of lipoid granulomatosis. Symmetric sclerosis of the meta- and diaphysis of long tubular bones are pathognomonic radiologic changes. Additionally, other skeletal segments can be affected. Extraskeletal manifestations can occur in almost all organs; lungs, pericardium, retroperitoneum, skin, and orbita play particularly important roles. The last case of 38 cases of Erdheim-Chester disease with an extraordinary mediastinal and perirenal involvement is described. For the second time following the initial description by Chester, an axial skeletal pattern of eburnated vertebra is shown.