MR imaging of pseudosarcoma in Paget’s disease of bone: a report of two cases

Pseudosarcoma is a rare manifestation of Paget’s disease of bone. We report the MR imaging of two cases highlighting the difficulties in diagnosis. One of the cases is the first time this condition has been described outside the long bones of the lower limb. Received: 11 July 2000 Revision requested: 10 August 2000 Revision received: 8 November 2000 Accepted: 15 November 2000     

Radiological patterns of childhood thoracic tuberculosis in a developed country: a single institution’s experience on 217/255 cases

The incidence of tuberculosis is increasing in the developed world and children in particular represent a high-risk group for developing the disease. The aim of this review is to analyse the spectrum of radiological signs as reported in the recent literature, in light of our series over a 15-year period, to pinpoint the most common radiological patterns in a developed country and to determine the role played by the different chest imaging techniques in diagnosis improvement. Lung TB was present in 217 out of 255 patients (85 %): 146 patients were under 5 years of age (76 under 2 years) and 71 over 5 years (41 over 10 years). We describe different patterns differentiating adolescents and young adults from infants and children. Adolescents and young adult tuberculosis are apical and cavitary. Thoracic TB in infants and children is characterized by lymph node and parenchymal disease. In 21 cases with lymphadenopathies without lymph-bronchial diffusion (age range 2 months–7 years), CT identified the Ghon focus in 16/21 cases; chest X-ray never identified the Ghon focus. In our series, pleural TB was present in 8 cases out of 146 under 5 years of age, 5 cases out of 76 under 2 years, and 18 cases out of 71 over 5 years. Radiologists should be aware of typical patterns of tuberculosis, to provide an early diagnosis.     

Heterogeneous signal in bone marrow on MRI of children’s feet: a normal finding?

Objective To describe the magnetic resonance (MR) appearances of the bone marrow of children’s feet and to determine their frequency and significance. Design and patients. A review of MR studies obtained in a retrospective series of 35 children with foot pain and in a prospective series of 19 asymptomatic children was performed. The MR appearances on T1-weighted, T2-weighted and STIR sequences were assessed and the frequency of patchy areas of low signal intenstiy on T1-weighted and high signal intenstiy on T2-weighted or STIR sequences was determined and correlated with clinical features. Results and conclusions. Low signal intenstiy on T1-weighted and high signal intenstiy on T2-weighted and STIR sequences were seen in 63% of symptomatic and 57% of asymptomatic children. In all cases where both feet were imaged, the changes were seen bilaterally. The marrow pattern varied from multiple discrete foci to more extensive confluent areas of high signal on the STIR sequence. These appearances are frequent and represent normal variation in the growing skeleton, and should not necessarily be interpreted as a sign of pathology. Received: 2 October 1998 Revision requested: 20 January 1999 Revision received: 18 February 1999 Accepted: 2 March 1999     

Unveiling the ‘unique bone’: a study of the distribution of focal clavicular lesions

AIM: Clavicle is a unique bone for many reasons. There is no study discussing the differential diagnosis of clavicular lesions based on the site of occurrence or age at presentation. This study aims to determine whether the distribution of lesions affecting the clavicle and age at presentation aid in the differential diagnosis of focal clavicular lesions. MATERIALS AND METHODS: Clinical notes, imaging and histopathological reports of the clavicular lesions between Jan 1999 and Jan 2006 were reviewed. Virtually, all patients had been referred as suspected neoplasm. RESULTS: Fifty-nine patients were identified. Patients <20 years (n = 27) had non-neoplastic or benign lesions. Patients between 20-50 years (n = 14) had predominantly non-neoplastic lesions. Patients >50 years (n = 18) had predominantly malignant lesions. The lesions most commonly affected the medial third (n = 35) and were predominantly non-neoplastic or benign. The middle third was affected in 15 patients and showed both benign and malignant lesions. The lateral third was least affected with predominance of malignant lesions. CONCLUSIONS: The clavicle is not a primary common site for any particular tumour; hence, diagnosis of the lesions can be challenging. Our study has suggested that few factors like age and site of the lesions may be helpful in diagnosis.     

Differential diagnosis of tumours and tumour-like lesions of the infrapatellar (Hoffa’s) fat pad: pictorial review with an emphasis on MR imaging

A variety of intrinsic and extrinsic tumours and tumour-like conditions may affect the infrapatellar (Hoffas) fat pad (IFP). MR imaging is the technique of choice in evaluating these conditions, but correlation with radiographs is important to identify those lesions producing mineralization. This pictorial review illustrates the spectrum of mass-like lesions that can affect the IFP, emphasizing the radiographic and MR findings that suggest a specific diagnosis.     

MDCT imaging of Alloderm biologic mesh spacers in the abdomen and pelvis — preliminary experience

The purpose of this study was to assess the attenuation characteristics of the Alloderm Biologic Mesh Spacer (ABMS) in the abdomen and pelvis. Of nine patients with ABMS, five underwent multidetector computed tomographic scans at 1, 4, and 7 months postsurgery. Two patients underwent positron emission tomography–computed tomography (PET–CT). The pre- and postcontrast images were evaluated for attenuation characteristics of ABMS. The PET–CT scans were reviewed for [18F]-fluorodeoxyglucose (FDG) uptake. We observed increase in the attenuation characteristics of the spacers on follow-up imaging (P< .05). No FDG uptake was noted on PET–CT. To conclude, ABMS demonstrates soft tissue attenuation on noncontrast CT and shows increase attenuation on serial CT scans.     

Magnetic resonance imaging for evaluation of disease activity in Crohn’s disease: a systematic review

To systematically review the evidence on the accuracy of MRI for grading disease activity in Crohn’s disease (CD). The MEDLINE, EMBASE, CINAHL and Cochrane databases were searched for studies on the accuracy of MRI in grading CD compared to a predefined reference standard. Two independent observers scored all relevant data. Three disease stages were defined: remission, mild and frank disease. The accuracy rates of MRI per disease stage were calculated by means of a random-effects model. Seven studies were included from a search resulting in 253 articles. In total 140 patients (16 patients in remission, 29 with mild disease and 95 with frank disease) were used for data analysis. MRI correctly graded 91% (95% CI: 84–96%) of patients with frank disease, 62% (95% CI: 44–79) of patients with mild disease and 62% (95% CI: 38–84) of patients in remission. MRI more often overstaged than understaged disease activity; MRI overstaged disease activity in 38% of patients in remission, mostly as mild disease. Overstaging of mild disease was observed in 21%, understaging in 17%. MRI correctly grades disease activity in a large proportion of patients with frank disease. For patients in remission or with mild disease, MRI correctly stages disease activity in many patients (62%).     

Clinical applications of susceptibility weighted MR imaging of the brain – a pictorial review

Introduction Susceptibility-weighted imaging (SWI) is a novel magnetic resonance (MR) technique that exploits the magnetic susceptibility differences of various tissues, such as blood, iron and calcification. This pictorial review covers many clinical conditions illustrating its usefulness. Methods SWI consists of using both magnitude and phase images from a high-resolution, three-dimensional fully velocity-compensated gradient echo sequence. Phase mask is created from the MR phase images, and multiplying these with the magnitude images increase the conspicuity of the smaller veins and other sources of susceptibility effects, which is depicted using minimal intensity projection (minIP). Results The phase images are useful in differentiating between diamagnetic and paramagnetic susceptibility effects of calcium and blood, respectively. This unique MR sequence will help in detecting occult low flow vascular lesions, calcification and cerebral microbleed in various pathologic conditions and aids in characterizing tumors and degenerative diseases of the brain. This sequence also can be used to visualize normal brain structures with conspicuity. Conclusion Susceptibility-weighted imaging is useful in differentiating and characterizing diverse brain pathologies.     

18F-FDG PET/CT bone/bone marrow findings in Hodgkin’s lymphoma may circumvent the use of bone marrow trephine biopsy at diagnosis staging

Purpose

Accurate staging of Hodgkin’s lymphoma (HL) is necessary in selecting appropriate treatment. Bone marrow trephine biopsy (BMB) is the standard procedure for depicting bone marrow involvement. BMB is invasive and explores a limited part of the bone marrow. ¹⁸F-FDG PET/CT is now widely used for assessing response to therapy in HL and a baseline study is obtained to improve accuracy. The aim of this retrospective analysis was to assess whether routine BMB remains necessary with concomitant ¹⁸F-FDG PET/CT.

Methods

Data from 83 patients (newly diagnosed HL) were reviewed. All patients had received contrast-enhanced CT, BMB and ¹⁸F-FDG PET/CT. Results of BMB were not available at the time of ¹⁸F-FDG PET/CT imaging.

Results

Seven patients had lymphomatous involvement on BMB. Four patients had bone involvement on conventional CT (two with negative BMB). All patients with bone marrow and/or bone lesions at conventional staging were also diagnosed on ¹⁸F-FDG PET/CT scan. PET/CT depicted FDG-avid bone/bone marrow foci in nine additional patients. Four of them had only one or two foci, while the other had multiple foci. However, the iliac crest, site of the BMB, was not involved on ¹⁸F-FDG PET/CT. Osteolytic/sclerotic lesions matching FDG-avid foci were visible on the CT part of PET/CT in three patients. MRI ordered in three other patients suggested bone marrow involvement. Interim and/or end-therapy ¹⁸F-FDG PET/CT documented response of FDG-avid bone/bone marrow foci to chemotherapy in every patient.

Conclusion

¹⁸F-FDG PET/CT highly improves sensitivity for diagnosis of bone/bone marrow lesions in HL compared to conventional staging.     

Accuracy of diagnostic imaging modalities for peripheral post-traumatic osteomyelitis – a systematic review of the recent literature

Aims

Post-traumatic osteomyelitis (PTO) is difficult to diagnose and there is no consensus on the best imaging strategy. The aim of this study is to present a systematic review of the recent literature on diagnostic imaging of PTO.

Methods

A literature search of the EMBASE and PubMed databases of the last 16 years (2000–2016) was performed. Studies that evaluated the accuracy of magnetic resonance imaging (MRI), three-phase bone scintigraphy (TPBS), white blood cell (WBC) or antigranulocyte antibody (AGA) scintigraphy, fluorodeoxyglucose positron emission tomography (FDG-PET) and plain computed tomography (CT) in diagnosing PTO were considered for inclusion. The review was conducted using the PRISMA statement and QUADAS-2 criteria.

Results

The literature search identified 3358 original records, of which 10 articles could be included in this review. Four of these studies had a comparative design which made it possible to report the results of, in total, 17 patient series. WBC (or AGA) scintigraphy and FDG-PET exhibit good accuracy for diagnosing PTO (sensitivity ranged from 50–100%, specificity ranged from 40–97% versus 83–100% and 51%–100%, respectively). The accuracy of both modalities improved when a hybrid imaging technique (SPECT/CT & FDG-PET/CT) was performed. For FDG-PET/CT, sensitivity ranged between 86 and 94% and specificity between 76 and 100%. For WBC scintigraphy?+?SPECT/CT, this is 100% and 89–97%, respectively.

Conclusions

Based on the best available evidence of the last 16 years, both WBC (or AGA) scintigraphy combined with SPECT/CT or FDG-PET combined with CT have the best diagnostic accuracy for diagnosing peripheral PTO.

     

Bone marrow edema syndrome of the foot: one year follow-up with MR imaging

OBJECTIVE: To describe the MR findings of bone marrow edema syndrome (BMES) of the foot and its evolution at 1 year follow-up. DESIGN AND PATIENTS: Twenty-five of 32 patients with disabling foot and ankle pain unrelated to trauma diagnosed as BMES when MR imaging demonstrated a bone marrow edema pattern in one or more bones without any radiological or underlying clinical cause, were re-evaluated by MR imaging 1 year later. RESULTS: On the initial MR examinations an average of 4.7 individual bones were involved by bone marrow edema. Soft tissue edema was present in every patient and joint effusion in 10 patients. MR imaging at 1 year showed resolution of bone edema in 18 patients (72%), partial improvement in five (20%) and no improvement in two (8%). Six patients (24%) developed similar symptoms in the other foot during follow-up. Ten of 17 available plain radiographs showed some loss of radiodensity. Further bone marrow edema developed in bones of the same foot that were initially normal, or in uninvolved distant bone marrow areas in the same affected bone, in six of seven patients on follow-up MR imaging. CONCLUSIONS: The evolution of the MR findings of BMES of the foot is to complete resolution or partial improvement at 1 year in the majority of cases. Migration to the other foot occurs in up to a quarter of patients.     

“Black bone” MRI: a potential alternative to CT when imaging the head and neck: report of eight clinical cases and review of the Oxford experience

Objective

The potential risks associated with ionising radiation are well documented. We have previously reported the “black bone” MRI sequence, useful when imaging cortical bone. The objective of this paper is to report our initial experience of this technique in patients undergoing imaging of the head and neck region.

Methods

Using the departmental database those patients having had “black bone” sequences of the head and neck performed as part of their MRI examination in the preceding 5 years were identified. The radiological reports were reviewed to identify those cases where “black bone” or conventional MRI sequences had been performed in place of the requested CT, and the patient medical records for these cases were reviewed. Medical record review was also conducted for those cases where it was considered that the pathological condition requiring imaging would ordinarily be investigated with CT.

Results

The “black bone” sequence had been performed in 69 patients as part of routine MRI of the head and neck. Of these, 67% (n=46) were performed in combination with CT imaging, the majority of cases being primary tumours. In four cases, an MRI was performed in place of the requested CT scan. We present eight clinical cases illustrating the potential benefits of the “black bone” sequence.

Conclusions

“Black bone” MRI offers a radiation-free method of imaging the head and neck, and has been successfully utilised in a range of benign and malignant conditions affecting this region.

Advances in knowledge

Adoption of this approach, where feasible, would be a significant advance in radiation protection.Hounsfield, in his 1973 paper on CT, stated that “the exposure of the patient to x-rays must be restricted” [1]. The potential risks of ionising radiation are well documented; however, we continue to fall short of Hounsfield’s advice because of increased imaging demands through a combination of defensive medicine, a decrease in exploratory surgery and the ability to meet the increased requests for CT. The largest increases in CT use have been in paediatric diagnosis and adult screening [2]. Further concern relates to the use of cone-beam CT, with scanners being installed and used in a rapidly increasing number of dental practices within the UK [3]. During the year 2002–3 the National Health Service in England [4] reported 1.7 million CT examinations, representing 8% of all X-ray examinations, and 6% of all imaging investigations. By 2009–10 this had risen to over 3.7 million: 13% and 10%, respectively. The United Nations Scientific Committee estimated that CT constitutes 5% of all X-ray examinations worldwide while accounting for about 34% of the resultant collective dose [5].The consensus among radiology professionals is that steps should be taken to reverse, or at least arrest, radiation exposure from CT [6]; yet for maxillo-cranio-facial imaging this has largely consisted of radiation reduction techniques and the introduction of cone-beam CT. The superior quality of bony imaging on CT and the ability to create three-dimensional (3D) rendered images of the craniofacial skeleton has maintained CT as the gold standard for this region.However, we have been increasingly utilising MRI when imaging the head and neck, following close collaboration between the MRI and oral and maxillofacial departments. In particular, we have previously reported the “black bone” MRI sequence for imaging cortical bone as a potential replacement for CT [7]. The technique utilises a low flip angle, with short repetition and echo times, to produce uniform contrast of the soft tissues, with densely black cortical bone. The imaging parameters are shown in

The role of nasoenteric intubation in the MR study of patients with Crohn??s disease: our experience and literature review

Purpose

The aim of this study was to compare magnetic resonance (MR) enteroclysis with MR enterography to verify whether nasoenteric intubation in patients affected by Crohn??s disease can provide supplementary information to that afforded by MR study of the small bowel.

Materials and methods

In a 12-month period, 40 patients (28 women and 12 men, mean age 35 years) affected by Crohn??s disease underwent MR imaging. Distension of the small-bowel loops was obtained by administering polyethylene glycol: 15 patients were given the mixture by mouth (MR enterography), whereas the remaining 25 received it via nasoenteric intubation (MR enteroclysis). Our study protocol included morphological sequences taken before and after intravenous injection of contrast medium and real-time functional sequences. Accuracy criteria for the execution of the examinations were designed according to 11 bands.

Results

Complete distension of the small-bowel loops was obtained in the 25 patients who underwent MR enteroclysis, with the additional advantage of a suitable assessment of those segments involved in the pathological process. This was not the case for the 15 patients who underwent MR enterography, because both the jejunum and the small-bowel loops appeared partially collapsed.

Conclusions

MR enteroclysis is the most effective technique for studying the small bowel in Crohn??s disease, as it not only provides a suitable morphological assessment but also supplies functional information.     

Diagnosis of perfusion abnormality of the pulmonary artery in Takayasu’s arteritis using contrast-enhanced MR perfusion imaging

To determine the clinical efficacy of contrast-enhanced magnetic resonance (MR) perfusion imaging in the diagnosis of perfusion abnormality in the pulmonary artery (PA) in Takayasu’s arteritis (TA). Twenty-one patients were evaluated. Pulmonary MR perfusion images were acquired using a 2-dimensional (2D) fast spoiled gradient echo sequence with single-slice technique (TR/TE, 5.3/1.3; flip angle, 30°; receiver bandwidth, 31.2 kHz/pixel; acquisition time, 0.7 s; and total acquisition time, 49 s). Seventy continuous subtracted MR images were evaluated, and the presence of perfusion abnormality was determined in lobe-based (n=126) and patient-based (n=21) analyses. Sensitivity, specificity, positive predictive value (PPV), and negative predictive values (NPV) were calculated using perfusion scintigraphy as a standard reference. For lobe-based analysis, sensitivity was 91.7–95.8%, specificity was 92.2–93.7%, and PPV and NPV were 73.3–76.7% and 97.9–99.0%, respectively. For patient-based analyses, sensitivity was 100%, specificity was 72.7%, and PPV and NPV were 76.9% and 100%, respectively. Kappa values for each analysis were between 0.78–1.00. In conclusion, MR perfusion imaging appears to be a valuable, noninvasive method to estimate PA involvement in patients with TA.     

Sonography of the painful shoulder: role of the operator’s experience

Objective  The aim of our study was to determine the role of the operator’s experience in the sonographic evaluation of the painful shoulder and to validate assumptions about its technical performance in routine practice. Materials and methods  Two radiologists, respectively standard and expert sonographic operators, independently and prospectively scanned 65 patients with clinical suspicion of rotator cuff lesion. Magnetic resonance arthrography was the reference standard. Results  The sensitivity of the expert ultrasound operator was 95.3% for full-thickness rotator cuff tears (41/43), 70.6% for partial-thickness tears (12/17), 64.3% for intratendinous tears (9/14), 100% for abnormality of the long head of biceps tendon (seven of seven), 88.9% for supraspinatus tendinosis (16/18), 96.4% for subacromial bursa abnormalities (53/55), and 91.7% for acromioclavicular joint osteoarthritis (33/36). The two sonographic operators were in very good agreement about full-thickness rotator cuff tears (κ = 0.90), supraspinatus tendinosis (κ = 0.80), abnormalities of the long head of biceps tendon (κ = 0.84), subacromial bursa abnormalities (κ = 0.89), and acromioclavicular osteoarthritis (κ = 0.81). The agreement was only moderate for partial-thickness tears (κ = 0.63) and intratendinous tears (κ = 0.57). Conclusions  Our results show that in moderately experienced hands as in experts’ hands, sonography has a low level of interobserver variability for full-thickness rotator cuff tears. Considering partial-thickness and intratendinous rotator cuff tears, our data suggest that interobserver variability is higher.     

Liver volumetry: Is imaging reliable? Personal experience and review of the literature

The amount of the future liver remnant volume is fundamental for hepato-biliary surgery, representing an important potential risk-factor for the development of post-hepatectomy liver failure. Despite this, there is no uniform consensus about the amount of hepatic parenchyma that can be safely resected, nor about the modality that should be chosen for this evaluation. The pre-operative evaluation of hepatic volume, along with a precise identification of vascular and biliar anatomy and variants, are therefore necessary to reduce surgical complications, especially for extensive resections. Some studies have tried to validate imaging methods [ultrasound, computed tomography (CT), magnetic resonance imaging] for the assessment of liver volume, but there is no clear evidence about the most accurate method for this evaluation. Furthermore, this volumetric evaluation seems to have a certain degree of error, tending to overestimate the actual hepatic volume, therefore some conversion factors, which should give a more reliable evaluation of liver volume, have been proposed. It is widespread among non-radiologists the use of independent software for an off-site volumetric analysis, performed on digital imaging and communications in medicine images with their own personal computer, but very few studies have provided a validation of these methods. Moreover, while the pre-transplantation volumetric assessment is fundamental, it remains unclear whether it should be routinely performed in all patients undergoing liver resection. In this editorial the role of imaging in the estimation of liver volume is discussed, providing a review of the most recent literature and a brief personal series of correlations between liver volumes and resection specimens’ weight, in order to assess the precision of the volumetric CT evaluation.