Nils Vetti

Magnetic resonance imaging of the alar and transverse ligaments in acute whiplash-associated disorders 1 and 2: a cross-sectional controlled study.

Study Design. Cross-sectional. Objective. To describe alar- and transverse-ligament magnetic resonance imaging (MRI) high-signal changes in acute whiplash-associated disorders (WAD) grades 1 and 2 in relation to the severity and mechanics of trauma, and to compare them with controls. Summary of Background Data. The alar and transverse ligaments are important stabilizers at the craniovertebral junction. Acute injury of these ligaments should be detected as high-signal changes on high-resolution MRI. Methods. In the study, 114 consecutive acute WAD 1–2 patients and 157 noninjured controls underwent upper-neck high-resolution MRI, using proton-weighted sequences and Short Tau Inversion Recovery (STIR). Two blinded radiologists independently graded high-signal changes 0 to 3 on proton images and assessed ligament high-signal intensity on STIR. Image quality was evaluated as good, reduced, or poor (not interpretable). Multiple logistic regression was used for both within- and between-groups analyses. Results. All proton and STIR images were interpretable. Interobserver agreement for grades 2 to 3 versus grades 0 to 1 changes was moderate to good (&kgr; = 0.71 alar; and 0.54 transverse). MRI showed grades 2 to 3 alar ligament changes in 40 (35.1%) and grades 2 to 3 transverse ligament changes in 27 (23.7%) of the patients. Such changes were related to contemporary head injury (P = 0.041 alar), neck pain (P = 0.042 transverse), and sex (P = 0.033 transverse) but did not differ between patients and controls (P = 0.433 alar; and 0.254 transverse). STIR ligament signal intensity, higher than bone marrow, was found in only three patients and one control. Conclusion. This first study on high-resolution MRI of craniovertebral ligaments in acute WAD 1–2 indicates that such trauma does not induce high-signal changes. Follow-up studies are needed to find out whether pretraumatic high-signal changes imply reduced ligament strength and can predict chronic WAD.

Follow-up MR imaging of the alar and transverse ligaments after whiplash injury: a prospective controlled study.

Whiplash injuries may damage the anterior longitudinal ligament, which is not critical because as long as the injury is isolated the spine remains stable. These authors studied 91 patients acutely and 12 months after whiplash injury with special attention to damaged transverse and alar ligaments. High proton density signal was seen in both injured and control patients with similar prevalence. Moreover, in those with a history of whiplash injury, these areas of high signal were seen in identical numbers acutely and on follow-up studies. Thus, these high signal areas, commonly assumed to represent injury to the ligaments, cannot be solely explained by trauma. BACKGROUND AND PURPOSE: The cause and clinical relevance of upper neck ligament high signal intensity on MR imaging in WAD are controversial. The purpose of this study was to explore changes in the signal intensity of the alar and transverse ligaments during the first year after a whiplash injury. MATERIALS AND METHODS: Dedicated high-resolution upper neck proton attenuation–weighted MR imaging was performed on 91 patients from an inception WAD1–2 cohort, both in the acute phase and 12 months after whiplash injury, and on 52 controls (noninjured patients with chronic neck pain). Two blinded radiologists independently graded alar and transverse ligament high signal intensity 0–3, compared initial and follow-up images to assess alterations in grading, and solved any disagreement in consensus. The Fisher exact test was used to compare proportions. RESULTS: Alar and transverse ligament grading was unchanged from the initial to the follow-up images. The only exceptions were 1 alar ligament changing from 0 to 1 and 1 ligament from 1 to 0. The prevalence of grades 2–3 high signal intensity in WAD was thus identical in the acute phase and after 12 months, and it did not differ from the prevalence in noninjured neck pain controls (alar ligaments 33.0% versus 46.2%, P = .151; transverse ligament 24.2% versus 23.1%, P = 1.000). CONCLUSIONS: Alar and transverse ligament high signal intensity in patients with WAD1–2 observed within the first year after injury cannot be explained by the trauma. Dedicated upper neck MR imaging cannot be recommended as a routine examination in these patients.

Are two readers more reliable than one? A study of upper neck ligament scoring on magnetic resonance images.

BackgroundMagnetic resonance imaging (MRI) studies typically employ either a single expert or multiple readers in collaboration to evaluate (read) the image results. However, no study has examined whether evaluations from multiple readers provide more reliable results than a single reader. We examined whether consistency in image interpretation by a single expert might be equal to the consistency of combined readings, defined as independent interpretations by two readers, where cases of disagreement were reconciled by consensus.MethodsOne expert neuroradiologist and one trained radiology resident independently evaluated 102 MRIs of the upper neck. The signal intensities of the alar and transverse ligaments were scored 0, 1, 2, or 3. Disagreements were resolved by consensus. They repeated the grading process after 3–8 months (second evaluation). We used kappa statistics and intraclass correlation coefficients (ICCs) to assess agreement between the initial and second evaluations for each radiologist and for combined determinations. Disagreements on score prevalence were evaluated with McNemar’s test.ResultsHigher consistency between the initial and second evaluations was obtained with the combined readings than with individual readings for signal intensity scores of ligaments on both the right and left sides of the spine. The weighted kappa ranges were 0.65-0.71 vs. 0.48-0.62 for combined vs. individual scoring, respectively. The combined scores also showed better agreement between evaluations than individual scores for the presence of grade 2–3 signal intensities on any side in a given subject (unweighted kappa 0.69-0.74 vs. 0.52-0.63, respectively). Disagreement between the initial and second evaluations on the prevalence of grades 2–3 was less marked for combined scores than for individual scores (P ≥ 0.039 vs. P ≤ 0.004, respectively). ICCs indicated a more reliable sum score per patient for combined scores (0.74) and both readers’ average scores (0.78) than for individual scores (0.55-0.69).ConclusionsThis study was the first to provide empirical support for the principle that an additional reader can improve the reproducibility of MRI interpretations compared to one expert alone. Furthermore, even a moderately experienced second reader improved the reliability compared to a single expert reader. The implications of this for clinical work require further study.

Intra- and inter-observer repeatability of radiographic measurements for previously slipped capital femoral epiphysis at skeletal maturity

Background Recent studies suggest that even a mild slip of the femoral capital epiphysis may lead to later degenerative changes when undiagnosed. However, little is written on the accuracy of radiographic measurements used to diagnose a slip at skeletal maturity. Purpose To assess the accuracy of radiographic measurements commonly used for assessment of previously slipped capital femoral epiphysis (SCFE) at skeletal maturity. Material and Methods All children born at our hospital during 1989 (n = 4006) were invited to participate in a follow-up hip trial at age 18–19 years. Erect pelvic anteroposterior and supine frog leg radiographs were obtained in a standardized fashion. For the purpose of this study, we selected a subset of 100 radiographs. To balance the data-set, we added another 28 radiographs from skeletal mature patients diagnosed and operated for a SCFE. Two observers independently measured Southwicks head-shaft angle, Murrays tilt-index, and the femoral head-neck angle. Intra- and inter-observer variation was assessed using the mean difference, with its 95% limits of agreement. Results A high percentage of the images (40%), particularly for the measurement of the Southwicks head-shaft angle, were judged immeasurable by at least one observer. Mean head-shaft angle was 11.0° (SD = 17.0), head-neck angle was 8.0° (SD = 12.0), and Murrays tilt-index was 1.18 (SD = 0.4). For head-shaft angle, the mean difference between measurements (Observer 2) was 0.8° (SD = 2.7°, 95% limits of agreement –4.5° to 6.1°), while the corresponding figure for the Murrays tilt-index was 0.02 (SD = 0.08, 95% limits of agreement –0.18 to 0.14), and for the head-neck angle 0.9° (SD = 4.0, 95% limits of agreement of –6.9° to 8.7°). Slightly higher variance was seen for Observer 1 and between the two observers. Conclusion Common radiographic measurements for the assessment of a previously slipped capital femoral epiphysis are relatively inaccurate in skeletal mature adolescents, in particular between observers (inter-observer), but also for the same observer (intra-observer). Our results underscore the importance of thorough standardization for both image and measurement technique when used in a clinical setting.

Traumatic dissection of the vertebral artery in a toddler following a short fall

Spontaneous subarachnoid haemorrhage (SAH) in children is uncommon, but is sometimes seen after rupture of aneurysms, and in different disorders. Traumatic SAH is common after serious accidental head injury, but is also reported after child abuse with vigorous shaking. To avoid unnecessary accusations of innocent care givers, it is important not to misinterpret the findings as abusive head trauma in small children with SAH. In the presented case, a nearly two-year-old girl was brought to the hospital after a fall witnessed by her father. The girl was unconscious, with elevated intracranial pressure, SAH and bilateral retinal haemorrhage (RH). She was pronounced dead after 9h. Premortem angiography revealed a dissection of the right vertebral artery, and postmortem examination revealed a traumatic lesion deep in the neck, at the base of the skull. Cerebral edema, in combination with SAH and RH, is highly suggestive of abusive head trauma. However, no external lesions, no skeletal lesions, especially no long bone metaphyseal lesions, or subdural haematomas occurring at the same time as SAH, were found. There was no report of previous child abuse in the family. Based on the radiological and postmortem findings, we believe that an accidental fall caused a blunt force trauma with a subsequent dissection of the right vertebral artery. To our knowledge, accidental tear of one of the vertebral arteries, leading to SAH in a toddler, has previously not been described. Child abuse is an important exclusion diagnosis with serious legal implications.

Metal artifact reduction in CT, a phantom study: subjective and objective evaluation of four commercial metal artifact reduction algorithms when used on three different orthopedic metal implants:

Background Metal implants may introduce severe artifacts in computed tomography (CT) images. Over the last few years dedicated algorithms have been developed in order to reduce metal artifacts in CT images. Purpose To investigate and compare metal artifact reduction algorithms (MARs) from four different CT vendors when imaging three different orthopedic metal implants. Material and Methods Three clinical metal implants were attached to the leg of an anthropomorphic phantom: cobalt-chrome; stainless steel; and titanium. Four commercial MARs were investigated: SmartMAR (GE); O-MAR (Philips); iMAR (Siemens); and SEMAR (Toshiba). The images were evaluated subjectively by three observers and analyzed objectively by calculating the fraction of pixels with CT number above 500 HU in a region of interest around the metal. The average CT number and image noise were also measured. Results Both subjective evaluation and objective analysis showed that MARs reduced metal artifacts and improved the image quality for CT images containing metal implants of steel and cobalt-chrome. When using MARs on titanium, all MARs introduced new visible artifacts. Conclusion The effect of MARs varied between CT vendors and different metal implants used in orthopedic surgery. Both in subjective evaluation and objective analysis the effect of applying MARs was most obvious on steel and cobalt-chrome implants when using SEMAR from Toshiba followed by SmartMAR from GE. However, MARs may also introduce new image artifacts especially when used on titanium implants. Therefore, it is important to reconstruct all CT images containing metal with and without MARs.

Successful eradication of leptomeningeal plasma cell disease

Abstract Plasma cell leukaemia (PCL) is a rare and aggressive form of malignant monoclonal gammopathy characterized by the presence of high levels of plasma cells in peripheral blood. Central nervous system involvement of PCL has no established treatment and an extremely poor prognosis. We here present a 59-year-old male patient diagnosed with PCL, initially treated with induction chemotherapy followed by autologous peripheral blood hematopoietic stem cell transplantation. After achieving a partial response, he relapsed and presented with leptomeningeal disease. He was then successfully treated with dexamethasone, pomalidomide, and an intrathecal combination of methotrexate, methylprednisolone and cytarabine. This cleared his cerebrospinal fluid from plasma cells achieving a durable partial response.

Bone marrow abnormalities detected by magnetic resonance imaging as initial sign of hematologic malignancies

The increasing use of radiological examination, especially magnetic resonance imaging (MRI), will probably increase the risk of unintended discovery of bone marrow abnormalities in patients where a hematologic disease would not be expected. In this paper we present four patients with different hematologic malignancies of nonplasma cell types. In all patients the MRI bone marrow abnormalities represent an initial presentation of the disease. These case reports illustrate the importance of a careful diagnostic follow-up without delay of patients with MRI bone marrow abnormalities, because such abnormalities can represent the first sign of both acute promyelocytic leukemia as well as other variants of acute leukemia.