Absent Anterior Cruciate Ligament.

This case report presents the MRI findings of aplasia of the anterior cruciate ligament with associated hypoplasia of the posterior cruciate ligament (Manner type 2). Radiographically the presence of a shallow femoral notch and hypoplastic tibial spines (the so-called "dromedar" sign) can aid in the diagnosis. Operative treatment is often not indicated since the congenital absence of the ACL implies longstanding altered biomechanics to which the knee has well adapted in the majority of cases.

Clinical significance of signal changes in the quadratus femoris muscle on MR.

OBJECTIVES: To evaluate the clinical significance of quadratus femoris muscle signal changes (QFMC) on MRI. METHODS: 204 consecutive bilateral MRI hip examinations (132 female, 72 male) were reviewed in retrospect for QFMC. Inclusion imaging parameters were edema or atrophy of the quadratus femoris muscle. The presence or absence of symptoms and additional ipsilateral and/or contralateral imaging findings were used to differentiate between isolated symptomatic, co-incidental and asymptomatic QFMC. RESULTS: 24 (11.8%) patients and 30 (7.3%) hips demonstrated QFMC. Atrophy was present in 5 symptomatic hips. Female to male ratio was 23:1. Isolated symptomatic QFMC: 4 hips (13.3%), 1 bilateral. Clinical symptoms in this group were non-specific greater trochanter pain and stiffness of the hip. Co-incidental QFMC: 19 symptomatic hips, ipsilateral associated findings present in 18 hips (94.7%) and contralateral additional findings present in 8 hips (42.1%). Asymptomatic QFMC: 7 hips (23.3%), ipsilateral associated asymptomatic findings in 5 hips (71.4%) and contralateral associated symptomatic findings in 6 hips (85.7%). Edema around the greater trochanter and hamstring insertions were the most frequent associated findings. CONCLUSION: In this study, most cases of QFMC were co-incidental or asymptomatic. In isolated symptomatic QFMC clinical complaints were non-specific. Atrophy was found only in the symptomatic hips.

Hearing loss as a presenting symptom of cleidocranial dysplasia.

OBJECTIVES: To report two cases of cleidocranial dysplasia in which hearing loss was the first presenting symptom. STUDY DESIGN: Retrospective case review. PATIENTS: Two cases of cleidocranial dysplasia, a rare autosomal dominant skeletal dysplasia affecting both membranous and enchondral bone formation. SETTING: Tertiary referral center. INTERVENTIONS: Clinical, audiometric, and imaging diagnostic procedures. CONCLUSION: With this report, we want to illustrate the possibility of a rare genetic disorder as the underlying cause of hearing loss. We also want to emphasize the need for a multidisciplinary approach and evaluation of unexplained hearing loss to obtain a correct diagnosis, which is important for genetic counseling and management of the patient and his or her family.

T1 relaxation times for viability evaluation of the engrafted and the native liver in a rat model of heterotopic auxiliary liver transplantation: a pilot study.

Following a heterotopic auxiliary liver transplantation, commonly used measurements are either invasive or non-indicative of individual viability of the coexisting engrafted and native livers. Magnetic resonance imaging (MRI) was therefore tested for its potential to monitor the post-transplant hepatic viability in a rat model. Thirteen Wistar rats were systematically evaluated with MRI and serum biochemical liver parameters. Post-transplant complications and the causes of animal death were identified by autopsy and histo-pathological examinations. The data of the healthy survivors were compared with those of the rats that developed complications. On MRI, the hepatic complications could be depicted in the individual livers. A specific pattern of signal evolution was found in the livers of the healthy survivors: the mean T1 relaxation times of the engrafted livers increased immediately after transplantation (476 +/- 64 ms, mean +/- standard deviation, pre-operative; 730 +/- 48 ms, week 1) and then declined steadily to a 3 month value of 489 +/- 246 ms, while, following a transient first rise (476 +/- 64 ms, pre-operative; 589 +/- 28 ms, week 1), the mean T1 value of the native livers increased again 4 weeks after surgery and reached a 3 month value of 859 +/- 43 ms. However, in the rats with various complications, the mean T1 relaxation times of the engrafted livers continued to increase throughout the first post-operative month (760 +/- 48 ms, week 1; 922 +/- 76 ms, week 4), while that of the native liver only varied mildly (546 +/- 25 ms, week 1; 473 +/- 25 ms, week 4). After the first post-transplant week, the healthy engrafted livers could already be distinguished from those with complications by a significant decrease in T1 relaxation times. These data suggest that, besides demonstrating major complications, MRI may allow one to monitor the viability of each liver by analysing the relative signal intensity and T1 relaxation times after a heterotopic auxiliary liver transplantation.

Neonatal infarction within basal cerebral vein territory.

In this report, an unusual intracranial haemorrhage in a term male infant born to a mother with diabetes is explained on the basis of occlusion of both basal veins of Rosenthal. This diagnosis relies on anatomical location and iconographic aspect of the clots. Evidence that this vessel is occluded cannot be ascertained from ultrasound or MR angiographic techniques in the neonatal period. The basal vein has not been implicated in previous reports of neonatal brain haemorrhage.

Imaging studies in the diagnostic workup of neonatal nasal obstruction.

Twelve neonates presenting with nasal obstruction after birth were evaluated by imaging studies for diagnostic reasons. Four groups were recognized: Group I: choanal atresia (n = 5) and choanal stenosis (n = 1); Group II: congenital nasal pyriform aperture stenosis (CNPAS) (n = 3) and holoprosencephaly (n = 1); Group III: nasolacrimal duct mucocele (n = 1); Group IV: nasal hypoplasia (n = 1). Associated anomalies were found in eight patients. Four patients with choanal atresia showed manifestations of the CHARGE (coloboma, congenital heart defect, atretic choanae, retarded physical and neuromotor development associated with central nervous system anomalies, genital hypoplasia, and ear anomaly and/or deafness) association. In the fifth patient with choanal atresia, the diagnosis of amnion disruption sequence was made. One patient with CNPAS had a solitary maxillary central incisor (SMCI), a mild form of holoprosencephaly. Besides proboscis and synophthalmos, SMCI was also present in the holoprosencephaly case. The patient with severe nasal hypoplasia had warfarin embryopathy. This review emphasizes the need for performing imaging studies in the diagnostic workup of neonates born with nasal obstruction.

CT and MRI of the semicircular canals in the normal and diseased temporal bone.

Imaging of the semicircular canals specifically is part of the imaging process of the temporal bone in general. The semicircular canals are easily seen on CT images and 3DFT-CISS-weighted MR images, both performed with 1.0-mm-thick slices, or even thinner slices. In selected cases, the T1-weighted images give unique information on the semicircular canals. This article briefly reviews the variety of semicircular canal anomalies that are most frequently present and can be routinely seen on CT and MR examinations of the temporal bone. It also provides a list that can be used by the radiologist in clinical practice to decide which technique, CT or MR, should be used to detect specific anomalies at the level of the semicircular canals.

Diagnostic imaging and clinical findings in rhombencephalosynapsis: case report and literature review.

Rhombencephalosynapsis is a rare condition in which most cases are found in newborns and infants. Morphological findings are predominantly characterized by fusion of the cerebellar hemispheres and absence of the vermis with often associated supratentorial anomalies. We review the literature with emphasis on diagnostic imaging of this condition and present a case of a 2-year-old girl.

Unilateral semicircular canal aplasia in Goldenhar's syndrome.

A patient with Goldenhar's syndrome (oculoauriculovertebral dysplasia) and unilateral aplasia of all semicircular canals is presented. This is the first report of such a finding and may support the hypothesis that Goldenhar's syndrome and the CHARGE association have a common pathogenetic mechanism.

Factor VIII Inhibitors. Natural autoantibodies and anti-idiotypes.

Natural antibodies to factor VIII are present in the normal antibody repertoire as other self-reactive antibodies to soluble proteins. The question as to whether they represent just a chance occurrence linked to the huge diversification of the antibody repertoire or whether these antibodies have an actual physiological relevance is not entirely settled. Evidence is in favor of a role in the maintenance of immune homeostasis, however, namely self-reactive antibodies are required to maintain the capacity of the immune system to distinguish self from nonself. Anti-factor VIII antibodies pose an interesting case in point because they exhibit the capacity to inhibit the function of factor VIII. Such a property is neutralized at least in part by the production of corresponding anti-idiotypic antibodies. Normal homeostasis can therefore be viewed as a network of interacting molecules, idiotypes, and anti-idiotypes; disruption of this equilibrium leads to the development of autoimmunity. A question that remains open for the time being is whether this network of interactions can be modulated in a defined way for the treatment of autoimmune reactions. This would mean either passive administration of anti-idiotypic antibodies or active immunization with idiotypes. The former has proved to be efficient, and the latter has still to be demonstrated. Further, and probably most importantly, is the question of the possible application of the idiotypic network concept to the treatment of hemophilia patients producing inhibitors. This essentially requires that an analysis of the anti-factor VIII immune response be carried out at the clonal level. Such work is ongoing in our laboratory.

Humanized severe combined immunodeficient mice as a potential model for the study of tolerance to factor VIII.

A Severe Combined Immunodeficient (SCID) mouse model has been established to evaluate experimental conditions leading to the production of factor VIII (FVIII) autoantibodies. To this end, we humanized 10 groups of 7 mice with peripheral blood mononuclear cells of 10 unrelated healthy blood donors (15 x 10(6) cells/mouse). Mice were injected with saline or immunized i.p. with 50 IU of a plasma derived human FVIII 24 h after reconstitution. Further immunization was made with 25 IU of FVIII every fortnight during 6 weeks and animals were sacrificed after 8 weeks. All reconstituted mice showed a spontaneous production of anti-FVIII antibodies in the absence of immunization with the corresponding antigen. However, no differences were observed regarding the quantity or the quality of these antibodies produced in the immunized or the saline group, indicating that tolerance to FVIII had been transferred with cell reconstitution. Affinity purified FVIII specific antibodies were capable of inhibiting FVIII activity and preventing the binding of FVIII to phospholipids in a dose-dependent manner. Immunoprecipitation experiments showed that the antibodies recognized only the C1 and C2 light chain domains. Since antibodies of interest can be found in the SCID mouse model and, moreover, since they are qualitatively comparable with the source donor's antibodies, this model provides a tool to study the regulation of tolerance against self antigens in normal subjects and in acquired haemophilia patients.

A novel cause of mild/moderate hemophilia A: mutations scattered in the factor VIII C1 domain reduce factor VIII binding to von Willebrand factor.

The mechanisms responsible for the low factor VIII (fVIII) activity in the plasma of patients with mild/moderate hemophilia A are poorly understood. In such patients, we have identified a series of fVIII mutations (Ile2098Ser, Ser2119Tyr, Asn2129Ser, Arg2150His, and Pro2153Gln) clustered in the C1 domain and associated with reduced binding of fVIII to von Willebrand factor (vWf). For each patient plasma, the specific activity of mutated fVIII was close to that of normal fVIII. Scatchard analysis showed that the affinity for vWf of recombinant Ile2098Ser, Ser2119Tyr, and Arg2150His fVIII mutants was reduced 8-fold, 80-fold, and 3-fold, respectively, when compared with normal fVIII. Given the importance of vWf for the stability of fVIII in plasma, these findings suggested that the reduction of fVIII binding to vWf resulting from the above-mentioned mutations could contribute to patients' low fVIII plasma levels. We, therefore, analyzed the effect of vWf on fVIII production by Chinese hamster ovary (CHO) cells transfected with expression vectors for recombinant B domain-deleted normal, Ile2098Ser, Ser2119Tyr, and Arg2150His fVIII. These 3 mutations impaired the vWf-dependent accumulation of functional fVIII in culture medium. Analysis of fVIII production by transiently transfected CHO cells indicated that, in addition to the impaired stabilization by vWf, the secretion of functional Ile2098Ser and Arg2150His fVIII was reduced about 2-fold and 6-fold, respectively, by comparison to Ser2119Tyr and normal fVIII. These findings indicate that C1-domain mutations resulting in reduced fVIII binding to vWf are an important cause of mild/moderate hemophilia A.

Effects of Re-arterialization on early graft function and regeneration in the rat model of heterotopic auxiliary liver transplantation.

In the rat model of heterotopic auxiliary liver transplantation, graft re-arterialization may influence the outcome of inter-liver competition. This was investigated in the current study using two transplanted groups with or without graft re-arterialization. Immediately after reperfusion, the re-arterialized grafts showed significantly higher bile flow rate and bilirubin excretion than the grafts without re-arterialization. DNA synthesis rate was also increased more drastically in the re-arterialized group following the transplantation. Without re-arterialization, the rats developed more pronounced cytolysis and cholestasis. Among the long-term survivors, all healthy re-arterialized grafts regenerated, whereas 5/6 non-re-arterialized grafts atrophied. These data demonstrate that the re-arterialization increases graft survival by improving early hepatic function, enhancing regenerative response and preventing post-transplant biliary complications in this rat model.

Perinatal cortical infarction within middle cerebral artery trunks.

AIM: To define neonatal pial middle cerebral artery infarction. METHODS: A retrospective study was made of neonates in whom focal arterial infarction had been detected ultrasonographically. A detailed study was made of cortical middle cerebral artery infarction subtypes. RESULTS: Forty infarctions, with the exception of those in a posterior cerebral artery, were detected ultrasonographically over a period of 10 years. Most were confirmed by computed tomography or magnetic resonance imaging. Factor V Leiden heterozygosity was documented in three. The onset was probably antepartum in three, and associated with fetal distress before labour in one. There were 19 cases of cortical middle cerebral artery stroke. The truncal type (n=13) was more common than complete (n = 5) middle cerebral artery infarction. Of six infarcts in the anterior trunk, four were in term infants and five affected the right hemisphere. Clinical seizures were part of the anterior truncal presentation in three. One of these infants, with involvement of the primary motor area, developed a severe motor hemisyndrome. The Bayley Mental Developmental Index was above 80 in all of three infants tested with anterior truncal infarction. Of seven patients with posterior truncal infarction, six were at or near term. Six of these lesions were left sided. Clinical seizures were observed in three. A mild motor hemisyndrome developed in at least three of these infants due to involvement of parieto-temporal non-primary cortex. CONCLUSIONS: Inability to differentiate between truncal and complete middle cerebral artery stroke is one of the explanations for the reported different outcomes. Severe motor hemisyndrome can be predicted from neonatal ultrasonography on the basis of primary motor cortex involvement. Clinical seizures were recognised in less than half of the patients with truncal infarction; left sided presentation was present in the posterior, but not the anterior truncal type of infarction. Asphyxia is a rare cause of focal arterial infarction.

Imaging of the normal pontine cisternal segment of the abducens nerve, using three-dimensional constructive interference in the steady state MRI.

Our objective was to determine the visibility of the cisternal segment of the normal abducens nerve using a three-dimensional Fourier-Transform constructive interference in the steady state (3DFT-CISS) sequence. Its visibility was rated in 150 patients without clinical evidence of abducens nerve disturbance. Axial 1-mm 3DFT-CISS images were obtained (TR/TE 17/7 ms, flip angle 50 degrees, field of view 160 mm, matrix 256 x 256). The cisternal segment was seen in 79% of cases, bilaterally in 73% and unilaterally in 11% of cases; neither cisternal segment was seen in 16% of cases. Identification of Dorello's canal was often of help in detecting the point lateral to the dorsum sellae at which the nerve pierces the dura mater. Flow artifacts and vascular loops in the pontine cistern sometimes caused problems in interpretation. 3DFT-CISS MRI with 1-mm-thick sections can however be considered a reasonably reliable technique for showing the cisternal segment of the abducens nerve.

The Lacrimo-Auriculo-Dento-Digital (LADD) syndrome: temporal bone CT findings.

The temporal bone CT examination of a 16-year-old female patient with the LADD syndrome or Levy-Hollister syndrome showed multiple bilateral middle as well as inner ear malformations. Ossicular chain anomalies were seen, especially of the incus and stapes. The oval window was very narrow to absent. Both cochleas were hypoplastic and showed modiolar deficiency. A common cavity between the vestibule and lateral semicircular canal was bilaterally present.

Neurocutaneous melanosis presenting with intracranial amelanotic melanoma.

We describe imaging findings in a 2-year-old girl with neurocutaneous melanosis and malignant cerebral melanoma. Because the cerebral melanoma in this child was of the amelanotic type, high-signal intensity on unenhanced T1-weighted images was not present. The cutaneous lesions played a crucial role in establishing a correct (presumed) histopathologic diagnosis on the basis of the imaging findings. To our knowledge this is the first report describing an intracranial amelanotic malignant melanoma in association with neurocutaneous melanosis.

Lyme disease in a child presenting with bilateral facial nerve palsy: MRI findings and review of the literature.

We report a 7-year-old boy with neuroborreliosis presenting with headache and bilateral facial nerve palsy. MRI demonstrated tentorial and bilateral facial and trigeminal nerve enhancement.