Forensic age estimation based on development of third molars: a staging technique for magnetic resonance imaging.

BACKGROUND: The development of third molars can be evaluated with medical imaging to estimate age in subadults. The appearance of third molars on magnetic resonance imaging (MRI) differs greatly from that on radiographs. Therefore a specific staging technique is necessary to classify third molar development on MRI and to apply it for age estimation. AIM: To develop a specific staging technique to register third molar development on MRI and to evaluate its performance for age estimation in subadults. MATERIALS AND METHODS: Using 3T MRI in three planes, all third molars were evaluated in 309 healthy Caucasian participants from 14 to 26 years old. According to the appearance of the developing third molars on MRI, descriptive criteria and schematic representations were established to define a specific staging technique. Two observers, with different levels of experience, staged all third molars independently with the developed technique. Intra- and inter-observer agreement were calculated. The data were imported in a Bayesian model for age estimation as described by Fieuws et al. (2016). This approach adequately handles correlation between age indicators and missing age indicators. It was used to calculate a point estimate and a prediction interval of the estimated age. Observed age minus predicted age was calculated, reflecting the error of the estimate. RESULTS: One-hundred and sixty-six third molars were agenetic. Five percent (51/1096) of upper third molars and 7% (70/1044) of lower third molars were not assessable. Kappa for inter-observer agreement ranged from 0.76 to 0.80. For intra-observer agreement kappa ranged from 0.80 to 0.89. However, two stage differences between observers or between staging sessions occurred in up to 2.2% (20/899) of assessments, probably due to a learning effect. Using the Bayesian model for age estimation, a mean absolute error of 2.0 years in females and 1.7 years in males was obtained. Root mean squared error equalled 2.38 years and 2.06 years respectively. The performance to discern minors from adults was better for males than for females, with specificities of 96% and 73% respectively. CONCLUSION: Age estimations based on the proposed staging method for third molars on MRI showed comparable reproducibility and performance as the established methods based on radiographs.

ISCHIOFEMORAL IMPINGEMENT DUE TO A SOLITARY EXOSTOSIS.

Ischiofemoral impingement is a rare cause of hip pain related to narrowing of the space between the ischial tuberosity and the lesser trochanter. It is usually seen in middle-aged women. We report a rare case of a young male patient presenting with ischiofemoral impingement due to a solitary exostosis at the lesser trochanter. Imaging, especially Magnetic Resonance Imaging (MRI), is an excellent tool to confirm the diagnosis by demonstrating narrowing of the ischiofemoral space and soft tissue edema in the muscle belly of the quadratus femoris muscle.

Direct comparison of conventional radiography and cone-beam CT in small bone and joint trauma.

OBJECTIVE: To compare the diagnostic value of cone-beam computed tomography (CBCT) and conventional radiography (CR) after acute small bone or joint trauma. MATERIALS AND METHODS: Between March 2013 and January 2014, 231 patients with recent small bone or joint trauma underwent CR and subsequent CBCT. CR and CBCT examinations were independently assessed by two readers, blinded to the result of the other modality. The total number of fractures as well as the number of complex fractures were compared, and inter- and intraobserver agreement for CBCT was calculated. In addition, radiation doses and evaluation times for both modalities were noted and statistically compared. RESULTS: Fracture detection on CBCT increased by 35% and 37% for reader 1 and reader 2, respectively, and identification of complex fractures increased by 236% and 185%. Interobserver agreement for CBCT was almost perfect, as was intraobserver agreement for reader 1. The intraobserver agreement for reader 2 was substantial. Radiation doses and evaluation time were significantly higher for CBCT. CONCLUSION: CBCT detects significantly more small bone and joint fractures, in particular complex fractures, than CR. In the majority of cases, the clinical implication of the additionally detected fractures is limited, but in some patients (e.g., fracture-dislocations), the management is significantly influenced by these findings. As the radiation dose for CBCT substantially exceeds that of CR, we suggest adhering to CR as the first-line examination after small bone and joint trauma and keeping CBCT for patients with clinical-radiographic discordance or suspected complex fractures in need of further (preoperative) assessment.

A rare case of diffuse alveolar hemorrhage following oral amphetamine intake.

Diffuse alveolar hemorrhage (DAH) is a clinical syndrome, which refers to injury to the capillaries, arterioles and venules, leading to red blood cell accumulation in the distal air spaces. It is defined by the clinical triad of hemoptysis, anemia and progressive hypoxemia. Chest radiographs reveal non-specific patchy or diffuse bilateral pulmonary consolidation. Multiple conditions are associated with DAH, of which Wegener's granulomatosis is the most frequent, and underlying disease determines the prognosis and treatment. This case describes DAH as a result of oral amphetamine abuse in a young patient of which the diagnosis was established by laboratory, clinical and radiologic findings. The patient experienced a rapid recovery without significant sequelae.

How sensitive and specific are MRI features of sacroiliitis for diagnosis of spondyloarthritis in patients with inflammatory back pain?

OBJECTIVE: To determine the sensitivity and specificity of MRI features of sacroiliitis in spondyloarthritis (SpA). MATERIALS AND METHODS: A retrospective study reviewed MRI of the sacroiliac (SI) joints in 517 patients with inflammatory back pain. Sensitivity, specificity, positive and negative likelihood ratios of active and structural lesions of sacroiliitis with final clinical diagnosis as golden standard was calculated. RESULTS: MRI showed active inflammation in 42% of patients (bone marrow oedema (BMO) (41.5%), capsulitis (3.3%), enthesitis (2.5%)) and structural changes in 48.8% of patients (erosion (25%), fat infiltration (31.6%), sclerosis (32%) and ankylosis (7.6%)). BMO was the MRI feature with the highest sensitivity (65.1%) for diagnosis of SpA. Capsulitis (99%), enthesitis (98.4%), ankylosis (97.4%) and erosion (94.8%) had a high specificity for diagnosis of SpA, whereas BMO (74.3%), sclerosis (75.8%) and fat infiltration (84.0%) were less specific. BMO concomitant with enthesitis, capsulitis or erosions increased the specificity. Concomitant presence of BMO and sclerosis or fat infiltration decreased the specificity. CONCLUSION: BMO is moderately sensitive and specific for diagnosis of SpA in patients with inflammatory back pain. BMO concomitant with enthesitis, capsulitis, ankylosis or erosion increases the specificity. Concomitant fat infiltration or sclerosis decreases the specificity for diagnosis of SpA. Of all lesions, erosion had by far the highest positive likelihood ratio for diagnosis of SpA.

Peroneal nerve: Normal anatomy and pathologic findings on routine MRI of the knee.

BACKGROUND: Peroneal nerve lesions are not common and are often exclusively assessed clinically and electromyographically. METHODS: On a routine MR examination without dedicated MR-neurography sequences the peroneal nerve can readily be assessed. Axial T1-weighted sequences are especially helpful as they allow a good differentiation between the nerve and the surrounding fat. RESULTS: The purpose of this article is to review the normal anatomy and pathologic conditions of the peroneal nerve around the knee. CONCLUSION: In the first part the variable anatomy of the peroneal nerve around the knee will be emphasized, followed by a discussion of the clinical findings of peroneal neuropathy and general MR signs of denervation. Six anatomical features may predispose to peroneal neuropathy: paucity of epineural tissue, biceps femoris tunnel, bifurcation level, superficial course around the fibula, fibular tunnel and finally the additional nerve branches. In the second part we discuss the different pathologic conditions: accidental and surgical trauma, and intraneural and extraneural compressive lesions. TEACHING POINTS: • Six anatomical features contribute to the vulnerability of the peroneal nerve around the knee. • MR signs of muscle denervation within the anterior compartment are important secondary signs for evaluation of the peroneal nerve. • The most common lesions of the peroneal nerve are traumatic or compressive. • Intraneural ganglia originate from the proximal tibiofibular joint. • Axial T1-weighted images are the best sequence to visualise the peroneal nerve on routine MRI.

Optimizing communication between the radiologist and the general practitioner.

Adequate communication between radiologist and referring general practitioner (GP) is mandatory in a good practice clinical setting. Several hurdles may interfere with good communication. Inappropriate imaging requests or incomplete clinical details conveyed to the radiologist may result in inappropriate imaging and interpretation. GPs may find the radiology report confusing or may feel it takes too much time to receive the reports. Communication issues may dissatisfy GPs and make them look for alternative providers for imaging referrals. In the digital era, electronic radiology request forms, digital access for the GP to radiology images and reports and networks centralizing patient data may all help to improve communication between radiologist and GP. In this paper we outline practical ways of improving this communication.

Proceedings of the Joint Meeting RBRS Bone Section and Nederlandse Vereniging Voor Skeletaradiologie, Leiden, The Netherlands, 25.0.3.2011-Part II. Tumors and tumorlike conditions of the calcaneous: the usual and the unusual.

The calcaneus is an uncommon site for involvement by tumors or tumorlike conditions of bone, although any lesion may involve the calcaneus. The purpose of this paper is to highlight the imaging features of common and uncommon tumors and tumorlike conditions occurring in the calcaneus. Typical case studies will illustrate the imaging findings on different imaging modalities.

MR imaging findings of lesions involving cartilage and bone in the paediatric knee: a pictorial review.

The knee is the joint which is most commonly imaged by MRI in children and adolescents. With increasing participation in competitive sports, traumatic knee injuries with osteochondral lesions are increasingly common in children. However, it is also important to exclude non traumatic conditions that result in defects of the articular cartilage and/or subchondral bone plate or growth plate of the knee, since timely diagnosis and therapy may help prevent lifelong disability in these patients. Moreover, there are normal variants that occur in the ossifying knee that should not be mistaken for lesions. The aim of this essay is to review the wide range of conditions that may result in MRI signal changes of the ossifying knee in children.

Incidental radiological finding of a renal tumour leading to the diagnosis of Birt-Hogg-Dube syndrome.

Birt-Hogg-Dubé (BHD) syndrome is a rare autosomal dominant condition characterised by benign tumours of the hair follicle, renal cancer, pulmonary cysts and spontaneous pneumothorax. We report the diagnosis of a BHD syndrome achieved after incidental radiological finding of a renal tumour in a 24-year old man. The patient also displayed recurrent pneumothoraces and showed to have cysts in the basis of both lungs. The association of recurrent pneumothoraces and renal neoplastic disease should alert for the possible presence of this syndrome.

Complications of bone tumors after multimodal therapy.

PURPOSE: To define and compare the complications of bone tumors after resection, extracorporeal irradiation and re-implantation, with or without radiotherapy. MATERIALS AND METHODS: Eighty patients (40 males and 40 females, ages 4-77 years) with 61 malignant and 19 benign bone tumors were evaluated for local and distant complications after treatment. Two groups of patients were studied: (1) 53 patients had resection without (43 patients) or with external beam radiotherapy (RadRx) (10 patients) and (2) 27 patients underwent extracorporeal irradiation and re-implantation without (22 patients) or with RadRx (5 patients). Patient follow-up varied from 1 month to 13.63 years with mean follow-up of 4.7 years. Imaging studies included bone and chest radiography, spin echo T1- and T2-weighted (or STIR) magnetic resonance imaging (MRI), dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), computed tomography (CT) for thoracic and abdominopelvic metastases and 3-phase technetium-99m-labeled-methylene-diphosphonate (Tc99m MDP) scintigraphy for bone metastases. RESULTS: DCE-MRI differentiated the rapidly enhancing recurrences, residual tumors and metastases from the slowly enhancing inflammation, and the non-enhancing seromas and fibrosis. Recurrences, metastases (mainly to lung and bone), and seromas were greater than twice as frequent in patients after resection than after ECCRI. Although 11.3% of post-resection patients had residual tumor, no ECRRI-treated patient had residual tumor. In contrast, after ECRRI, infection was almost three times as frequent and aseptic loosening twice as frequent as compared with the post-resection patients. Bones treated with RadRx and/or ECRRI showed increased prevalence of fractures and osteoporosis. In addition, muscle inflammation was more common in the externally irradiated patient as compared with the patient who did not receive this therapy. However, another soft tissue complication, heterotopic ossification, was rare in the patient after RadRx, but 25.6% of patients after resection and 40.9% after ECRRI showed heterotopic ossification. Unusual complications after resection or ECRRI involved adjacent nerves with partial denervation, amputation neuroma, or entrapment (secondary to recurrence or fibrosis) after resection or ECRRI with or without RadRx. One patient developed a posterior tibial artery pseudoaneurysm after ECRRI. CONCLUSIONS: Follow-up of patients with benign and malignant bone tumors demonstrated the efficacy of DCE-MRI for distinguishing rapidly enhancing viable tumor from the slowly enhancing or non-enhancing benign processes after different therapies. Although recurrences, residual tumors, metastases and seromas were more common after resection, fractures, osteoporosis, infection, and muscular atrophy predominated in the ECRRI-treated patient. RadRx further predisposed post-resection and post-ECRRI patients to develop fractures, osteoporosis and infection and was the major cause of persistent muscle inflammation at MRI. Because complications can evolve and resolve years after treatment, the patients with bone tumors, particularly sarcomas, must receive life-time multimodal imaging for maximal diagnosis and treatment.

MRI evaluation of a new scaffold-based allogenic chondrocyte implantation for cartilage repair.

AIM: The present study was designed to evaluate the implantation of alginate beads containing human mature allogenic chondrocytes for the treatment of symptomatic cartilage defects of the knee. MRI was used for the morphological analysis of cartilage repair. The correlation between MRI findings and clinical outcome was also studied. METHODS: A biodegradable, alginate-based biocompatible scaffold containing human mature allogenic chondrocytes was used for the treatment of symptomatic chondral and osteochondral lesions in the knee. Twenty-one patients were prospectively evaluated with use of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the Visual Analogue Scale (VAS) for pain preoperatively and at 3, 6, 9 and 12 months of follow-up. Of the 21 patients, 12 had consented to follow the postoperative MRI evaluation protocol. MRI data were analyzed based on the original MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) and modified MOCART scoring system. The correlation between the clinical outcome and MRI findings was evaluated. RESULTS: A statistically significant clinical improvement became apparent after 6 months and patients continued to improve during the 12 months of follow-up. One of the two MRI scoring systems that were used, showed a statistically significant deterioration of the repair tissue at 1 year of follow-up. Twelve months after the operation complete filling or hypertrophy was found in 41.6%. Bone-marrow edema and effusion were seen in 41.7% and 25% of the study patients, respectively. We did not find a consistent correlation between the MRI criteria and the clinical results. DISCUSSION: The present study confirmed the primary role of MRI in the evaluation of cartilage repair. Two MOCART-based scoring systems were used in a longitudinal fashion and allowed a practical and morphological evaluation of the repair tissue. However, the correlation between clinical outcome and MRI findings was poor. Further validation of these scoring systems is mandatory. The promising short-term clinical outcome of the allogenic chondrocytes/alginate beads implantation was not confirmed by the short-term MRI findings.

Whole body MR imaging in neurofibromatosis type 1.

OBJECTIVE: To assess the value of whole body MR imaging in patients with neurofibromatosis type 1 (NF1). MATERIALS AND METHODS: 24 patients (15-59 years; mean and median 36 years; 7 males; 17 females) with genetically proven neurofibromatosis type 1 were examined with whole body MR imaging. Axial and coronal T1- and fat-suppressed T2-weighted images (slice thickness 6-12 mm) were acquired on a 1.5T MR unit (Symphony; Siemens, Erlangen, Germany). The images were reviewed by 2 radiologists: 1 senior, 1 junior. The criterion for a neurofibroma was a mass lesion with low signal intensity on T1 and high signal intensity on T2, along the course of a nerve. The location, size, general morphology and course along plexuses and nerves were evaluated. Cutaneous and subcutaneous neurofibromas were defined as "superficial" neurofibromas. The other neurofibromas were regarded as "deep" neurofibromas. RESULTS: There were no major problems to differentiate neurofibromas from lymph nodes, vessels or cysts. The latter three were easily recognised by their typical shape and location, whereas neurofibromas occurred in regions where no mass lesion was anatomically expected. There was no relation between age and total number of neurofibromas throughout the body. Classification according to location and number of neurofibromas: 8 patients had only superficial neurofibromas, 1 only deep and 15 both superficial and deep lesions. Twelve patients had less than 15 neurofibromas and 12 had more. Classification according to course: in 8 patients the neurofibromas occurred along plexuses or proximal part of the intercostal nerves; in 16 patients the lesions were more peripheral. Classification according to morphology: 4 patients had plexiform neurofibromas and 20 patients had multiple solitary lesions. Twelve of these 20 patients had less than 15 lesions, and 8 had more. In 2 patients multiple solitary neurofibromas occurred along the nerve in a chain configuration. In one patient a clinically unsuspected brain tumour was found. CONCLUSION: Whole body MR imaging is a reliable method to evaluate the distribution, size and morphology of neurofibromas in patients with NF1.

Post-treatment complications of soft tissue tumours.

PURPOSE: To identify local and distant complications of patients with soft tissue tumours and evaluate their relationships to types of therapy. METHODS AND MATERIALS: Fifty-one patients (29 males and 22 females, ages 14-80 years) with 34 malignant and 17 benign soft tissue tumours were evaluated for local and distant complications after resection or amputation only (26 patients) or after the addition of radiotherapy (25 patients: 17 patients had external beam therapy, 7 patients had external beam therapy and brachytherapy, and one patient had extracorporeal irradiation and reimplantation). Duration of follow-up averaged 3.75 years for malignant tumours and 2.79 years for benign tumours. Follow-up studies included radiography, T1- and T2-weighted magnetic resonance (MR) imaging, dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), computed tomography for thoracic and abdominal metastases, and 3-phase technetium-99m-labeled-methylene-diphosphonate scintigraphy for bone metastases. RESULTS: Recurrent tumours were 2.2 times more frequent in patients who had undergone their initial resection at an outside hospital as compared with those first treated at the university hospital. Nine of 11 recurrences occurred after marginal surgery. Metastases from soft tissue sarcomas, most commonly to lung (nine patients) and to bone and muscle (five patients), showed no specific relationship to type of therapy. DCE-MRI differentiated rapidly enhancing soft tissue recurrences (11 patients) and residual tumours (6 patients) from slowly enhancing muscle inflammation, and non-enhancing fibrosis and seromas that usually did not enhance. Seromas developed in 76% of patients who had postoperative radiation therapy and in 7.7% of patients who had only surgery. Subcutaneous and cutaneous oedema and muscle inflammation was at least four times more frequent after adjunct radiotherapy than after resection alone. Irrespective of the type of treatment, inflammatory changes in muscle and subcutaneous and cutaneous tissue and the majority of seromas were evident at the first follow-up study. Although seromas after resection and external beam therapy resolved with time, seromas after additional brachytherapy persisted. Inflammatory changes in muscle and cutaneous and subcutaneous tissue after resection alone disappeared by the second follow-up study, whereas these changes after radiotherapy resolved months to years after treatment. Fourteen of 51 patients showed MR findings of chronic muscular atrophy, predominantly located in the lower extremity. Heterotopic ossification was seen in three patients after resection and amputation without radiotherapy. Except for one patient with aggressive fibromatosis, bone and nerve complications occurred in patients with soft tissue malignancy. Twelve patients had osteoporosis. Six patients sustained fractures in irradiated osteoporotic bone of the lower extremity, and one patient had a vertebral fracture in radiographically normal but irradiated bone. In addition, one patient was found to have a medullary infarct in an irradiated femur. In nerve entrapment, DCE-MRI demonstrated the rapidly enhancing recurrent tumour or non-enhancing fibrosis surrounding the slowly enhancing nerve. T1- and T2-weighted MR images displayed the acute and chronic sequelae of nerve entrapment and nerve transection with denervation as T2-hyperintense acute muscle atrophy or T1-hypertense chronic fatty muscular atrophy with decrease in muscle volume. CONCLUSION: This study suggests a possible relationship between types of treatment of soft tissue tumours and subsequent complications. Postoperative radiotherapy was associated with a significant number of patients with seromas, muscle, cutaneous and subcutaneous inflammation, and fractures. Incomplete or difficult surgery resulted in residual or recurrent tumours and heterotopic ossification. Muscle atrophy and nerve entrapment were related to both treatments (resection alone or radiotherapy after resection). Diligent follow-up of patients with soft tissue tumours with recognition of these complications and their differentiation from recurrent or residual tumour can help guide clinical care and may negate the need for surgery when benign disease is defined.

Imaging of the opacified middle ear.

Middle ear opacification on imaging studies performed in a non-traumatic setting mostly reflects chronic inflammatory/infectious disease. In some of these patients an underlying cholesteatoma will be found. High-resolution computed tomography examinations and magnetic resonance imaging are often used in the work-out of the disease. High-resolution computed tomography of the opacified middle ear serves to describe the status of the ossicular chain, and its suspensory apparatus, as well as the status of the tympanic and mastoid wall. When ossicular erosions are visualized, the probability of a present cholesteatoma is about 90%. Whereas high-resolution computed tomography is not able to differentiate cholesteatoma from other types of opacification, magnetic resonance imaging is. The combined use of delayed post-Gd T1-weighted images and non-EPI based DWI seems to be the actual best option on this matter.

Health technology assessment of magnetic resonance imaging of the knee.

A search of the available literature was performed and the role of MR imaging of the knee is discussed. Based on this search the authors concluded that MR has a high sensitivity in detecting any abnormalities in the knee but it does not have the same diagnostic accuracy as a clinical investigation performed by a trained knee specialist when all knee injuries are taken together. It does lead to a decrease in the number of surgical interventions due to its high negative predictive value. For the detection of meniscal injury, MR has the same accuracy as arthroscopy and should be performed in order to avoid unnecessary surgical interventions. A negative MR also obviates further investigation in suspected cartilage damage. This is not true for anterior and posterior cruciate ligament problems where MRI is less accurate than clinical investigation.

Health technology assessment of magnetic resonance.

MR imaging has established itself as a reliable means of imaging pathology in many different regions of the body without the disadvantage of ionizing radiation. There was also hope that MRI might replace not only CT but also more invasive imaging techniques. Until now the substitution, especially that of CT has been less than expected. To evaluate the possible substitution of CT by MR imaging, it is paramount to have high quality evidence regarding the efficacy of MRI. This was collected by performing a systematic search of the available literature using Medical Subject Heading (MeSH) terms. The retrieved articles were classified according to the different levels of diagnostic efficacy as described by Fryback and Thornbury. Based on the available studies and the quality assessment, a level of evidence is attributed for the diagnostic efficacy of MRI in each indication.