Differentiation of bone and bone marrow infarcts from osteomyelitis in sickle cell disorders

To determine whether imaging techniques can differentiate osteomyelitis from bone infarction in sickle cell disorders, 39 sets of bone scans (BS) and bone marrow scans (BMS) were performed on 31 patients with sickling disorders and bone pain. In addition, three patients who had either a BS or a BMS were included. Results were analyzed according to whether scans were performed three days or less (Period 1), four to six days (Period 2), or seven or more days (Period 3) after the onset of pain. Regardless of the period, all but five BMS for 34 episodes of assumed infarction showed decreased uptake. BS findings varied depending on the time interval, with none of the ten in Period 1 showing increased uptake, but all 11 in Period 3 showing increased uptake. However, in Period 2, about half of the 13 BS showed increased uptake. All three patients with osteomyelitis in Period 3 had increased uptake on BS. The BMS done in one of these patients showed decreased uptake. Three patients with cellulitis had normal BS and BMS. One patient with septic arthritis had normal BMS, but slightly increased uptake on BS. Although typical imaging patterns are present in early and late infarction (Periods 1 and 3), the patterns for late infarction may not differ from those of advanced osteomyelitis. Therefore, imaging studies are only of value in differentiating infarction from osteomyelitis when both BS and BMS are performed soon after the appearance of symptoms.     

Actinomycetes as the causative organism of osteomyelitis in sickle cell disease

The case of a 17-year-old girl with sickle cell anaemia who presented with extensive osteomyelitis due to actinomycetes is reported. Osteomyelitis in the long bones due to actinomycosis is extremely rare. A review of the literature reveals only six cases in which actinomycetes have been isolated from lesions affecting a long bone. The occurrence of this condition in sickle cell haemoglobinopathy has not been previously reported.     

3D fat-saturated T1 SPACE sequence for the diagnosis of cervical artery dissection

Introduction

This study aims to demonstrate the added value of a 3D fat-saturated (FS) T1 sampling perfection with application-optimised contrast using different flip angle evolutions (SPACE) sequence compared to 2D FS T1 spin echo (SE) for the diagnosis of cervical artery dissection.

Methods

Thirty-one patients were prospectively evaluated on a 1.5-T MR system for a clinical suspicion of acute or subacute cervical artery dissection with 3D T1 SPACE sequence. In 23 cases, the axial 2D FS T1 SE sequence was also used; only these cases were subsequently analysed. Two neuroradiologists independently and blindly assessed the 2D and 3D T1 sequences. The presence of recent dissection (defined as a T1 hyperintensity in the vessel wall) and the quality of fat suppression were assessed. The final diagnosis was established in consensus, after reviewing all the imaging and clinical data.

Results

Overall sensitivity and specificity were 0.929 and 1 for axial T1 SE, and 0.965 and 0.945 for T1 SPACE (P?>?0.05), respectively. The two readers had excellent agreement for both sequences (k?=?1 and 0.8175 for T1 SE and T1 SPACE, respectively; P?>?0.05). The quality of the fat saturation was similar. Very good fat saturation was obtained in the upper neck. Multiplanar reconstructions were very useful in tortuous regions, such as the atlas loop of the vertebral artery or the carotid petrous entry. 3D T1 SPACE sequence has a shorter acquisition time (3 min 25 s versus 5 min 32 s for one T1 SE sequence) and a larger coverage area.

Conclusion

3D T1 SPACE sequence offers similar information with its 2D counterpart, in a shorter acquisition time and larger coverage area.     

Detection of acute osteomyelitis with indium-111 labeled white blood cells in a patient with sickle cell disease

A young patient with sickle cell disease (SCD) and multiple hospitalizations for crisis was admitted because of suspected osteomyelitis. Initial laboratory work, radiographs, and bone images were not contributory. An In-111 white blood cell (WBC) study demonstrated two areas of increased radionuclide uptake consistent with osteomyelitis. One of these had associated soft tissue infection. No other areas of active osteomyelitis were visualized, in spite of the presence of several additional infection sites. Imaging with In-111 WBC is probably not justified for routine diagnosis of acute osteomyelitis in areas free of previous disease, where conventional bone images are highly efficient. In-111 WBC imaging, however, may be helpful in detecting osteomyelitis in selected patients with SCD in whom Tc-99m bone images and radiographs are usually abnormal and difficult to interpret due to previous bone infarcts. Localization of the infection focus is very important in choosing the aspiration site for bacteriologic studies. A negative study, however, should be interpreted cautiously.     

Quantitative MR imaging of children with sickle cell disease: Striking T1 elevation in the thalamus

Nineteen patients with sickle cell disease (SCD) were examined with conventional MR imaging (cMRI), including T1- and T2-weighted sequences and MR angiography (MRA). qMRI mapping of T1 was also done using a precise and accurate inversion-recovery (PAIR) technique optimized and validated previously. In addition, 21 healthy African-American control subjects had the qMRI examination. Nonparametric Kruskal-Wallis analysis of variance of control subjects, of SCD patients without stroke, and of SCD patients with stroke showed that T1 increased with disease severity in the thalamus, frontal white matter, genu, and occipital white matter. T1 was significantly longer in SCD patients without stroke (n=13) than in control subjects (n=21) in the thalamus and frontal white matter. In addition, T1 values were significantly longer in SCD patients with stroke than in patients without stroke in the genu and frontal white matter. Abnormality of the thalamus was identified by qMRI in a substantial fraction of patients read as normal by both cMRI and MRA, suggesting that it may be possible to use T1 elevation to identify a subset of patients with SCD who are at elevated risk for stroke.     

Hepatic iron deposition in patients with sickle cell disease: Role of breath-hold multiecho T2-weighted MRI sequence

Introduction

The purpose of this study is to detect the role of breath-hold multiecho T2^∗-weighted MRI, in quantification of hepatic iron deposition in patients with sickle cell disease.

Methods

Thirty-seven patients underwent 1.5-T MRI of the liver that included a multiecho T2^∗-weighted sequence. Hepatic T2^∗ iron grading was done for each patient by placing regions of interest in the hepatic parenchyma. Hepatic T2^∗ values were correlated with histopathological iron grade. Liver biopsy was done for all patients. Written consent was obtained from all patients prior to MRI studies.

Results

Thirty-two patients (86.5 %) had evidence of hepatic iron deposition on histopathological examination, including eight (25%) with grade 3, eleven (34%) with grade 2 and thirteen patients (41%) with grade 1.Patients with negative iron deposition histologically, had T2^∗ values ranging from 28–32 ms. For the patients with positive hepatic iron deposition, hepatic T2^∗ decreased with increasing iron grade.Statistical analysis showed that for differentiation of hepatic iron deposition grade 3 from grades 1 and 2, hepatic T2^∗ less than 13 ms had a sensitivity and specificity of 100 % and 98%, respectively.

Conclusion

Breath-hold multiecho T2^∗-weighted MRI sequence offers an accurate estimation of hepatic iron deposition.     

Technetium-99m white blood cell imaging: false-negative result in salmonella osteomyelitis associated with sickle cell disease

The authors report a case of sickle cell anemia associated osteomyelitis where the Tc-99m white blood cell imaging was negative, and bone imaging showed increased uptake in the region in question. The reasons for the possible false-negative image are discussed.     

A prospective study of soft-tissue ultrasonography in sickle cell disease patients with suspected osteomyelitis

AIM: A prospective study was done to assess the accuracy of soft tissue ultrasonography in patients with sickle cell disease (SCD) presenting with suspected osteomyelitis. MATERIALS AND METHODS: Thirty-one SCD patients had soft tissue ultrasonography on 38 occasions (18 men, 13 women; mean age 8.2 years). The initial ultrasonographic signs and diagnosis were compared with the final clinical diagnosis, which was based on clinical progress and scintigraphy. RESULT: The overall sensitivity of ultrasound in diagnosing osteomyelitis was 74% with a specificity of 63%. The principal ultrasonographic finding of subperiosteal fluid was present in 14 (74%) patients with osteomyelitis and seven (37%) patients without infection. A finding of a subperiosteal fluid depth of 4 mm or more was significantly associated with osteomyelitis (P < 0.01). CONCLUSION: Ultrasonography should be the initial investigation in SCD patients if osteomyelitis is suspected clinically. In such a clinical setting, a finding of 4 mm depth or more of subperiosteal fluid appears to be diagnostic. Previous statements that the presence of any subperiosteal fluid indicates infection are shown to be inaccurate. Patients with less than 4 mm of subperiosteal fluid require further imaging or aspiration to establish the diagnosis of osteomyelitis.     

Acute soft head syndrome in a sickle cell disease patient

Acute soft head syndrome is an extremely rare complication in children with sickle cell anemia. We present a 16-year old male patient known to have sickle cell anemia who presented to our emergency department with low grade fever, headache, skull pain and swelling. Magnetic Resonance of the brain was done demonstrating subgaleal collections overlying calvarial signal abnormalities. The combination of clinical and radiological findings were indicative of acute soft head syndrome. Acute soft head syndrome is a rare complication in children with sickle cell anemia and the pathophysiology is related to osteonecrosis and bone infarcts of the calvarium as well as secondary reactive sub-galeal collections. Treatment includes conservative management with intravenous fluids and analgesics, in addition, our patient was treated with antibiotics since differentiation clinically and by imaging can be challenging. Acute soft head syndrome should be considered in the differential diagnosis of headache and skull swelling in children with sickle cell anemia.     

Optimal 3-T MRI for depiction of the finger A2 pulley: comparison between T1-weighted, fat-saturated T2-weighted and gadolinium-enhanced fat-saturated T1-weighted sequences

Objective To compare three spin-echo sequences, transverse T1-weighted (T1WI), transverse fat-saturated (FS) T2-weighted (T2WI), and transverse gadolinium-enhanced (Gd) FS T1WI, for the visualisation of normal and abnormal finger A2 pulley with magnetic resonance (MR) imaging at 3 tesla (T). Materials and methods Sixty-three fingers from 21 patients were consecutively investigated. Two musculoskeletal radiologists retrospectively compared all sequences to assess the visibility of normal and abnormal A2 pulleys and the presence of motion or ghost artefacts. Results Normal and abnormal A2 pulleys were visible in 94% (59/63) and 95% (60/63) on T1WI sequences, in 63% (40/63) and 60% (38/63) on FS T2WI sequences, and in 87% (55/63) and 73% (46/63) on Gd FS T1WI sequences when read by the first and second observer, respectively. Motion and ghost artefacts were higher on FS T2WI sequences. Seven among eight abnormal A2 pulleys were detected, and were best depicted with Gd FS T1WI sequences in 71% (5/7) and 86% (6/7) by the first and the second observer, respectively. Conclusion In 3-T MRI, the comparison between transverse T1WI, FS T2WI, and Gd FS T1WI sequences shows that transverse T1WI allows excellent depiction of the A2 pulley, that FS T2WI suffers from a higher rate of motion and ghost artefacts, and transverse Gd FS T1WI is the best sequence for the depiction of abnormal A2 pulley.     

qMRI relaxometry of mandibular bone marrow: A monomodal distribution in sickle cell disease

Purpose:

To identify and characterize sickle cell disease (SCD)‐related changes in the composition of mandibular bone marrow using qMRI relaxometry histograms.

Materials and Methods:

Thirteen SCD patients and 17 controls underwent brain MR imaging with the mixed turbo spin‐echo (TSE) pulse sequence at 1.5T. The mandible was manually segmented and divided into body, angle, ramus, and condyle. T1 and T2 histograms of each mandible were modeled with Gaussian functions. The relaxation time histogram peaks were calculated, and the number of monomodal versus bimodal curves was compared.

Results:

SCD patients exhibited monomodal distributions on both T1 and T2 histograms, consistent with a composition of predominantly red hematopoietic marrow. Eighty‐eight percent of mandibles in control subjects exhibited a bimodal distribution in T1 and all showed a bimodal distribution in T2, indicating mixed but predominantly yellow marrow composition. The second peak in control subjects was shorter in T1 and longer in T2, consistent with yellow marrow composition.

Conclusion:

Instead of physiological fatty replacement, SCD patients exhibit red marrow persistence in the mandible, likely due to the increased demand for hematopoiesis. This phenomenon can be manifested by a monomodal curve in both T1 and T2 relaxometric histograms. J. Magn. Reson. Imaging 2013;37:1182–1188. © 2012 Wiley Periodicals, Inc.