Initial experience with FSE STIR whole-body MR imaging for staging lymphoma in children

Our objective was to compare fast spin-echo (FSE) short inversion time inversion recovery (STIR) whole-body MR imaging with standard procedures in staging children with lymphoma. Eight children (age range, 2–16 years) underwent multi-station FSE STIR whole-body MR at initial staging (n=5) or for restaging following completion of therapy (n=5). Whole-body MR and conventional staging procedures, including CT (n=10), gallium-67 scintigraphy (n=9), bone scintigraphy (n=3) and bone marrow biopsy (n=7) were retrospectively compared for detection of sites involved by lymphoma and for the assigned stage. FSE STIR whole-body MR detected more sites of possible lymphomatous involvement at initial staging (87/88) and at restaging (5/5) than did conventional imaging (74/88, 3/5). MR was more sensitive than conventional imaging in detecting bone marrow involvement at initial staging. Following treatment, however, residual and therapy-induced bone marrow signal abnormalities could not be differentiated from lymphomatous involvement. Detection of nodal and visceral involvement correlated well. Our results suggest that FSE STIR whole-body MR imaging is a sensitive technique for evaluating lymphomatous involvement of bone marrow as well as non-marrow sites. Larger prospective trials are needed to determine if FSE STIR whole-body MR can replace standard radiographic procedures for initial staging and contribute in the follow-up of lymphoma in children.     

“One-stop-shop” staging: Should we prefer FDG-PET/CT or MRI for the detection of bone metastases?

Aim

The aim of this study was to compare the diagnostic accuracy of fully diagnostic, contrast-enhanced whole-body FDG-PET/CT and whole-body MRI for detection of bone metastases in patients suffering from newly diagnosed non-small cell lung cancer and malignant melanoma.

Material and Methods

109 consecutive non-small cell lung cancer (n = 54) and malignant melanoma (n = 55) patients underwent whole-body FDG-PET/CT and whole-body MRI for initial tumor staging. All images were evaluated by four experienced physicians (three radiologists, one nuclear medicine physician). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for detection of bone metastases were determined for both modalities. Statistically significant differences between FDG-PET/CT and MRI were calculated with Fisher's Exact test (p < 0.05). Clinical and imaging follow-up data with a mean follow-up time of 434 days served as the reference standard.

Results

According to the reference standard 11 patients (10%) suffered from bone metastases. The sensitivity, specificity, PPV, NPV, and accuracy for the detection of osseous metastases was 45%, 99%, 83%, 94%, and 94% with whole-body FDG-PET/CT and 64%, 94%, 54%, 96%, and 91% with whole-body MRI. The difference was not statistically significant (p = 0.6147).

Conclusions

FDG-PET/CT and MRI seem to be equally suitable for the detection of skeletal metastases in patients suffering from newly diagnosed non-small cell lung cancer and malignant melanoma. Both modalities go along with a substantial rate of false-negative findings requiring a close follow-up of patients who are staged free of bone metastases at initial staging.     

Potential impact of PET/CT on the initial staging of lymphoma

Purpose

The aim of this study was to investigate the potential impact of PET/CT on the initial staging of lymphoma with comparison to each of the PET and CT components alone.

Materials and methods

PET/CTs from 37 patients with lymphoma undergoing initial staging were studied. Review of PET, CT and PET/CT images were done and staging of each patient by each modality was assigned and compared together. Clinical follow-up, additional imaging and histology served as the standard of reference.

Results

PET/CT correctly diagnosed 83 nodal regions as positive for lymphomatous involvement versus 61 and 57 detected by PET and CT respectively. The respective sensitivities, specificities, and accuracies for the detection of nodal involvement were: PET: 88.4%, 65%, 94%, CT 89.1%, 60.1%, 96.1%, PET/CT 96.3%, 88.3%, 98.2%. PET/CT also correctly identified more extra-nodal lesions (n = 24) than CT (n = 16) and PET (n = 15). Correct staging was more accurate at PET/CT (n = 31) in comparison to PET alone (n = 23) and CT alone (n = 21).

Conclusions

PET/CT was superior to PET and CT in the initial staging of lymphoma with significant better performance compared to PET and CT to clarify nodal and extra-nodal involved sites. The application of PET/CT rather than CT or PET is likely to be more beneficial.     

Avascular necrosis (AVN) of the proximal fragment in scaphoid nonunion: is intravenous contrast agent necessary in MRI?

Purpose

The purpose of this prospective study is to assess the diagnostic value of intravenously applied contrast agent for diagnosing osteonecrosis of the proximal fragment in scaphoid nonunion, and to compare the imaging results with intraoperative findings.

Materials and methods

In 88 patients (7 women, 81 men) suffering from symptomatic scaphoid nonunion, preoperative MRI was performed (coronal PD-w FSE fs, sagittal-oblique T1-w SE nonenhanced and T1-w SE fs contrast-enhanced, sagittal T2*-w GRE). MRI interpretation was based on the intensity of contrast enhancement: 0 = none, 1 = focal, 2 = diffuse. Intraoperatively, the osseous viability was scored by means of bleeding points on the osteotomy site of the proximal scaphoid fragment: 0 = absent, 1 = moderate, 2 = good.

Results

Intraoperatively, 17 necrotic, 29 compromised, and 42 normal proximal fragments were found. In nonenhanced MRI, bone viability was judged necrotic in 1 patient, compromised in 20 patients, and unaffected in 67 patients. Contrast-enhanced MRI revealed 14 necrotic, 21 compromised, and 53 normal proximal fragments. Judging surgical findings as the standard of reference, statistical analysis for nonenhanced MRI was: sensitivity 6.3%, specificity 100%, positive PV 100%, negative PV 82.6%, and accuracy 82.9%; statistics for contrast-enhanced MRI was: sensitivity 76.5%, specificity 98.6%, positive PV 92.9%, negative PV 94.6%, and accuracy 94.3%. Sensitivity for detecting avascular proximal fragments was significantly better (p < 0.001) in contrast-enhanced MRI in comparison to nonenhanced MRI.

Conclusion

Viability of the proximal fragment in scaphoid nonunion can be significantly better assessed with the use of contrast-enhanced MRI as compared to nonenhanced MRI. Bone marrow edema is an inferior indicator of osteonecrosis. Application of intravenous gadolinium is recommended for imaging scaphoid nonunion.     

Osteoradionecrosis of the upper cervical spine: MR imaging following radiotherapy for nasopharyngeal carcinoma

Purpose

To document the MRI appearances of radiation-induced abnormalities in the cervical spine following treatment for nasopharyngeal carcinoma (NPC).

Methods

Patients with radiation-induced abnormalities in the upper cervical spine were identified from a retrospective analysis of reports from patients undergoing MRI follow-up. Imaging and clinical records of these patients were reviewed. Symmetrical distribution of abnormalities at C1 (anterior arch ± adjacent aspect of the lateral masses) and C2 (dens ± body especially with a characteristic horizontal rim of marrow preservation above the inferior endplate) were considered typical for osteoradionecrosis (ORN).

Results

Abnormalities of C1/2 were identified in 9/884 (1%) patients. The MRI distribution of abnormalities was typical for ORN in four and atypical in five patients. Abnormal soft tissue was present in the atlantoaxial joint in eight patients, forming a florid mass in six. This soft tissue was in direct continuity with the posterior nasopharyngeal wall ulceration via the retropharyngeal region. The final clinical diagnosis was ORN in eight, five of whom had clinical factors which suggested infection could have played a contributory role, and osteomyelitis in one patient. All patients had undergone additional radiotherapy treatment comprising of brachytherapy (7), stereotactic radiotherapy (1) or radiotherapy boost (2) and three had undergone nasopharyngectomy.

Conclusion

ORN of the upper cervical spine following radiotherapy for NPC is more common than previously suspected and is seen in patients with additional treatment, especially brachytherapy. MRI features are often atypical and a contributory role of infection in the development of some cases of ORN is postulated.     

Preoperative staging of renal cell carcinoma using triphasic helical computed tomography

Objective

To determine if staging of renal cell carcinoma (RCC) can be predicted from preoperative triphasic helical computed tomography (CT) findings.

Patients and methods

We reviewed the triphasic helical CT scans of 48 consecutive patients with pathologic diagnosis RCCs. All tumors were staged according to the 2002 version of TNM staging system. The preoperative radiologic staging was compared with postoperative pathologic staging. Agreement between the two staging systems was determined using the kappa test.

Results

Comparison between triphasic helical CT staging and pathologic staging showed harmony in all lesions in stage T1a, and T1b. Triphasic helical CT over diagnosed two cases of stage T1b regarded as stage T3a while agreement was noted in all cases of stage T2. Harmony was noted between triphasic helical CT and pathologic staging in two lesions stage T3a, four lesions in stage T3b, and two lesions stage T4. The agreement between triphasic helical CT and pathologic T stages was perfect (K = 0.941). Forty-two cases were staged N0, one case was N1, and five cases were staged N2 by triphasic CT. Three cases were over staged, and six cases were under staged while, 39 were correctly N staged. The agreement between triphasic helical CT and pathologic N staging was poor (K = 0.33).

Conclusion

The agreement between the preoperative triphasic helical CT staging and postoperative pathologic T staging is perfect, while agreement in N stages is poor. So T staging of RCC can be predicted from triphasic helical CT findings while N staging cannot be predicted preoperatively.     

Magnetic resonance imaging of active sacroiliitis: Do we really need gadolinium?

Introduction

Magnetic resonance imaging (MRI) of active inflammatory changes of the sacroiliac joint (SIJ) in spondyloarthritis (SpA) is performed with short tau inversion recovery (STIR) sequences and fat-saturated T1-weighted fast spin-echo (FSE) sequences after administration of gadolinium-based contrast medium (T1/Gd). The aim of the present study was to compare these two pulse sequences in terms of diagnosis, diagnostic confidence, and quantification of inflammatory changes.

Materials and methods

The study included 105 patients with suspected SpA; 72 patients developed clinical SpA over time. All patients were examined with STIR and T1/Gd and each of the two sequences was analyzed separately in conjunction with unenhanced T1 FSE images. For quantitative estimation of inflammatory changes, each sacroiliac joint (SIJ) was divided into 4 quadrants (and severity per quadrant was assigned a score of 0-4, resulting in a maximum sum score of 16 per SIJ). Diagnostic confidence was assessed on a visual analogue scale ranging from 0 to 10.

Results

Active sacroiliitis was diagnosed in 46 patients and ruled out in 34 using STIR, whereas findings were inconclusive in 25 patients. The corresponding numbers for T1/Gd were 47, 44, and 14. Diagnostic confidence was significantly lower for STIR (7.3 ± 2.6) compared with T1/Gd (8.7 ± 1.9) (p < 0.001).The sum scores were 2.5 (±3.3) for STIR and 2.2 (±3.2) for T1/Gd for the right SIJ and 2.2 (±2.9) (STIR) and 1.9 (±3.1) (T1/Gd) for the left SIJ. Agreement was high with intraclass correlation coefficient (ICC) values of 0.86 for the right SIJ and 0.90 for the left SIJ and positive correlation (r = 0.62 right, 0.60 left).

Summary

STIR sequences alone are sufficient for establishing a reliable diagnosis and quantify the amount of inflammation in active sacroiliitis. A contrast-enhanced study is dispensable in patients with established disease or in the setting of clinical follow-up studies. However, a contrast-enhanced MR sequence is beneficial to ensure maximum diagnostic confidence when patients with early sacroiliitis are examined.     

The role of ultrasound imaging in the evaluation of peripheral nerve in systemic sclerosis (scleroderma)

Background

Patients affected by scleroderma may complain of sensory disturbances especially in the hands.

Purpose

To study the imaging features of upper limb nerves in patients affected by scleroderma (SSc).

Materials and method

Twenty-five patients affected only by SSc were prospectively evaluated with high-resolution US and magnetic resonance (MRI) or computer tomography (CT) when necessary (2 patients). Median and ulnar nerves were evaluated bilaterally. Nerve conduction studies were performed in the symptomatic patients (n = 10). Results of imaging studies were correlated with disease duration, autoimmunity and immunosuppression. Nerves of SSc patients were compared with a control group of 90 patients matched for age and body mass index.

Results

The prevalence of sensory disturbances revealed by clinical examination was 40%. In symptomatic SSc patients (n = 10) US evaluation revealed nerve abnormalities in 70% of cases (n = 7/10). n = 2 had a carpal tunnel syndrome. n = 5 had cubital tunnel syndrome. In two of them CT and MR were necessary to identify the compressed nerve at the level of the elbow due to the presence of calcifications. There was no association between the presence of an entrapment neuropathy and disease duration, autoantibodies and immunosuppression.

Conclusion

Ultrasound, CT and MR may detect nerve abnormalities in 70% of SSc patients complaining of neurologic disturbances in the hands. The results of imaging studies support the hypothesis of a vascular dependent neuropathy in SSc.     

Observer variation of magnetic resonance imaging and diffusion weighted imaging in pelvic lymph node detection

Aim

Conventional MRI and the recently developed diffusion weighted imaging (DWI) technique both are being used for the detection of pelvic lymph node metastasis in gynaecologic cancers. Little is known about the reproducibility of DWI. This study assesses the reproducibility of pelvic lymph node detection by conventional MRI and DWI.

Materials and methods

17 patients with gynaecological malignancies eligible for curative surgery were selected as population of interest. They had undergone preoperative conventional MRI and DWI on a 3.0 T MR scanner. All images were evaluated by two experienced radiologists. Inter- and intra-observer agreements were assessed, and whether lymph node size and region were related to reproducibility. Differences were tested by Chi-square statistics.

Results

The reproducibility ranged between 42% and 65% for the two observers and for the two imaging tests, conventional MRI and DWI. Higher percentages of agreement were found for larger lymph nodes, i.e. for long as well as short axis diameter exceeding 5 mm. Also, agreement was better for lymph nodes in the external iliac region and the obturator region compared to detection of lymph nodes in the common iliac area. Results for the newer technique, DWI, were comparable to the results of the more conventional MRI sequences.

Conclusion

Reproducibility of MRI and DWI in the detection of pelvic lymph nodes in patients with a gynaecological malignancy was similar. For lymph nodes exceeding 5 mm in both long and short axis diameter the agreement was considerably better than for smaller nodes.     

Analysis of perfusion weighted image of CNS lymphoma

Purpose

It is difficult to differentiate CNS lymphoma from other tumors such as malignant gliomas, metastases, or meningiomas with conventional MR imaging, because the imaging findings are overlapped between these tumors. The purpose of this study is to investigate the perfusion weighted MR imaging findings of CNS lymphomas and to compare the relative cerebral blood volume ratios between CNS lymphomas and other tumors such as high grade gliomas, metastases, or meningiomas.

Materials and methods

We retrospectively reviewed MRI findings and clinical records in 13 patients with pathologically proven CNS lymphoma between January 2006 and November 2008. We evaluated the relative cerebral blood volume ratios of tumor, which were obtained by dividing the values obtained from the normal white matter on MRI.

Results

Total 13 patients (M:F = 8:5; age range 46-67 years, mean age 52.3 years) were included. The CNS lymphomas showed relatively low values of maximum relative CBV ratio in most patients regardless of primary or secondary CNS lymphoma.

Conclusion

Perfusion weighted image may be helpful in the diagnosis of CNS lymphoma in spite of primary or secondary or B cell or T cell.     

Persistent bone marrow edema after osteochondral autograft transplantation in the knee joint

Background and objective

The assessment of bone marrow edema-like signal intensity in magnetic resonance imaging (MRI) in patients after osteochondral autograft transplantation (OCT) in the knee joint is a parameter of yet indefinite value. This study determines the prevalence of persistent edema-like signal intensity in OCT patients and evaluates the correlation between edema and morphological imaging findings of the graft and clinical pain symptoms.

Materials and methods

In this longitudinal observational study, 10 patients after OCT were followed by MRI prospectively 1 month, 3 months, 6 months, 12 months, and 24 months post-operatively. All MR examinations were performed on a 1.0 T MR unit with the same protocol using a modified scoring system (magnetic resonance observation of cartilage repair tissue—MOCART) for evaluation. Edema-like signal intensity in and beneath the osteochondral graft was assessed in its prevalence and graded using a coronal short tau inversion recovery fast spin echo (STIR-FSE) sequence: grade 1, normal; grade 2, moderate (diameter <2 cm); grade 3, severe (diameter >2 cm). The finding of edema-like signal intensity was correlated with graded parameters describing the morphology of the repair tissue assessed in a sagittal dual FSE sequence including: (a) surface of repair tissue: grade 1, intact; grade 2, damaged. (b) Cartilage interface: grade 1, complete; grade 2, incomplete. (c) Bone interface: grade 1, complete; grade 2, delamination. The finding of edema-like signal intensity was also correlated with the KOOS pain score assessing knee pain after 12 months.

Results

Initially, after 1 month the prevalence of edema-like signal intensity was 70% (7/10 patients) and finally after 24 months 60% (6/10 patients). We found no significant relationship between the prevalence and degree of edema-like signal intensity and parameters describing the morphology of the repair tissue. Also the clinical pain score did not show significant correlation with edema.

Conclusion

Persistent bone marrow edema-like signal intensity in MRI is frequently found in patients after OCT and may post-operatively continue for years without significant relation to delamination and loss of the graft and knee pain.     

Susceptibility-weighted imaging in grading brain astrocytomas

Objective

To evaluate the value of intratumoral vessels and micro-hemorrhage shown in susceptibility weighted imaging (SWI) for grading brain astrocytomas and to analyze the difference between SWI and conventional imaging techniques.

Methods

22 patients with astrocytomas were diagnosed with surgical specimens, 9 of which were grades I-II, and 13 were grades III-IV. All examinations were performed on Signa DEx 3.0 T MRI scanner. Conventional imaging techniques (T1WI, T2WI, T2FLAIR, CE-T1WI) and SWI sequence were used. The parameters of SWI sequence were the following: TR = 35 ms, TE = 20 ms, FA = 15°, slice thickness = 2 mm. The small vessels and blood products of the tumors in SW images were analyzed. The differences between the two groups in SW images were analyzed statistically.

Results

The findings in SW images of brain astrocytomas were correlated strongly with pathology. SWI was more sensitive compared to conventional imaging techniques for showing small vessels and micro-hemorrhage in brain astrocytomas. Statistical comparison showed that the small vessels and micro-hemorrhage of two groups of brain astrocytomas in SW images differed significantly.

Conclusion

SWI is superior to conventional imaging techniques at showing the small vessels and micro-hemorrhage in brain astrocytomas, which plays an important role in the tumor grading.     

Abnormal findings in hallucal sesamoids on MR imaging—Associated with different pathologies of the forefoot? An observational study

Background

To evaluate the prevalence and localization of abnormalities in the hallucal sesamoids detectable by magnetic resonance (MR) imaging in patients with forefoot pain and to determine which pathologies of tarsus, metatarsus and phalanges are associated with these abnormalities.

Materials and methods

The forefoot MRI examinations of 50 consecutive patients (32 females, 18 males; mean age 51 years, age range 20-86 years) were retrospectively analyzed by two musculoskeletal radiologists. A minimum of coronal and sagittal T1-weighted images and STIR images or T2-weighted images with fat saturation were performed on a 1.5-T scanner. Abnormal findings in the sesamoids were correlated with pathology in the I.MTP (metatarsal-phalangeal) joint, pathology in other parts of the forefoot and clinical information.

Results

Signal abnormalities of the sesamoids were found in 7 patients out of 50 (14%). Two patients presented a bone marrow edema (BME) in both sesamoids, in 1 patient only the lateral one was affected; all three associated with pathology and pain in the I.MTP joint. In four patients only the medial sesamoid was affected, not associated with pathology in the I.MTP joint but with pathology in other parts of the forefoot.

Conclusion

The prevalence of signal abnormalities in hallucal sesamoids was 14%. BME of the lateral sesamoid or of both were predominantly associated with pathology in the I.MTP joint. In contrast, signal abnormalities of the medial sesamoid, without affection of the lateral one, were associated with pathology in other parts of the forefoot suggesting an overuse injury as a result of compensating posture.     

Non-contrast-enhanced hepatic MR angiography: Do two-dimensional parallel imaging and short tau inversion recovery methods shorten acquisition time without image quality deterioration?

Objective

To study whether shortening the acquisition time for selective hepatic artery visualization is feasible without image quality deterioration by adopting two-dimensional (2D) parallel imaging (PI) and short tau inversion recovery (STIR) methods.

Materials and methods

Twenty-four healthy volunteers were enrolled. 3D true steady-state free-precession imaging with a time spatial labeling inversion pulse was conducted using 1D or 2D-PI and fat suppression by chemical shift selective (CHESS) or STIR methods. Three groups of different scan conditions were assigned and compared: group A (1D-PI factor 2 and CHESS), group B (2D-PI factor 2 × 2 and CHESS), and group C (2D-PI factor 2 × 2 and STIR). The artery-to-liver contrast was quantified, and the quality of artery visualization and overall image quality were scored.

Results

The mean scan time was 9.5 ± 1.0 min (mean ± standard deviation), 5.9 ± 0.8 min, and 5.8 ± 0.5 min in groups A, B, and C, respectively, and was significantly shorter in groups B and C than in group A (P < 0.01). The artery-to-liver contrast was significantly better in group C than in groups A and B (P < 0.01). The scores for artery visualization and overall image quality were worse in group B than in groups A and C. The differences were statistically significant (P < 0.05) regarding the arterial branches of segments 4 and 8. Between group A and group C, which had similar scores, there were no statistically significant differences.

Conclusion

Shortening the acquisition time for selective hepatic artery visualization was feasible without deterioration of the image quality by the combination of 2D-PI and STIR methods. It will facilitate using non-contrast-enhanced MRA in clinical practice.     

Musculoskeletal manifestations of sickle cell disease,diagnosis with whole body MRI

Purpose

The aim of work is to define the musculoskeletal abnormalities in patients with sickle-cell disease using whole body MRI.

Patients and methods

Twenty-seven patients with known sickle cell disease were included in this study complaining of acute painful vaso-occlusive crisis. All the patients complaining of bony pain in different body regions. Some patients complaining of bony swellings and joint pain. Whole body (W.B) MRI studies were performed for all the patients .Three coronal (T1, T2, and STIR) sequences were performed for whole-body MR imaging. In selected cases, dedicated examination of certain body parts was performed.

Results

Persistent red marrow, intramedullary bone hyperplasia and bone infarcts were seen in all patients. Vertebral bone infarcts were found in 23 patients. Bilateral proximal femoral head epiphysis avascular necrosis were found in 9 patients. Osteomylitis was diagnosed in 6 patients and septic arthritis in 2 patients.

Conclusion

Whole body MRI can help identifying muscloskeletal abnormalities in sickle cell disease in a single session. MRI is a useful imaging tool in distinguishing acute osteomylitis and bone infarct. Knowledge of the range of imaging findings is crucial in order to accurately depict the complication and initiate appropriate therapy.     

Diagnostic imaging in Merkel cell carcinoma: Lessons to learn from 16 cases with correlation of sonography, CT, MRI and PET

Objective

The authors report imaging findings in a series of 16 patients with MCC, a rare tumour which is often managed primarily by a dermatologist. To our knowledge, no equivalent series of MCC has been described in the nuclear medicine literature.

Material and Methods

In this IRB-approved retrospective noncomparative case series 16 patients with biopsy-proven Merkel cell carcinoma were included between January 1999 and October 2007. Twenty-nine whole body PET scans (18F-FDG n = 24, 18F-FDOPA n = 5) in 16 patients were retrospectively reviewed with regard to tracer uptake in six anatomical sites per patient. For 127/144 of FDG-PET evaluated regions and 68/144 of regions depicted by conventional imaging methods, a valid standard of reference could be obtained. A combined standard of reference was applied, which consisted of histopathology (lymphadenectomy or biopsy) or clinical or radiological follow-up for at least 12 months. Results: the mean FDG uptake over the clinicopatholigical verified FDG avid areas was 4.7 SUV (1.5-9.9 SUV). The region based assessment of diagnostic value, in consideration of the standard of reference, resulted in a sensitivity of 85.7% and a specificity of 96.2% of FDG-PET (n = 127) and in a combined sensitivity of 95.5% and a specificity of 89.1% for morphological imaging methods (n = 68). Differences between methods did not reach statistical significance (p = 1.00, p = 0.18).

Conclusions

FDG-PET is a highly useful whole body staging method of comparable value compared to conventional imaging methods with restricted field of view. The lessons learned from case series are discussed.     

PET/CT in initial staging and therapy response assessment of early mediastinal lymphoma

Objective

To detect accuracy of PET/CT in the initial staging, response after the first line and end of treatment in early mediastinal lymphoma patients compared to contrast CT.

Materials and methods

We studied 50 patients with pathologically proven lymphoma with a mean age = 27.5. All patients were at early stage. All patients performed CT and PET/CT for initial staging, after the first course of chemotherapy (after 4–6 weeks) and at the end of treatment (after 2–4 months).

Results

PET/CT upstaged 5 cases. At first line of treatment, PET/CT and CECT were agreeable in 32% of cases. PET/CT showed 100% sensitivity, 96.7% specificity, 95% positive predictive value and 100% negative predictive value. At the end of treatment both methods showed a 46% agreement. PET/CT was statistically significant in the follow up of hilar and axillary lymph nodes. PET/CT showed 100% sensitivity and specificity; compared to 62.5% sensitivity and 97.6% specificity for CECT in detection of extra-nodal disease sites.

Conclusion

PET/CT proved higher sensitivity and specificity over CECT. The major strength of PET/CT over CECT was its higher ability for detection of extra-nodal sites of lymphoma and excluding active disease in residual nodal mass lesions on follow up.     

The meniscofibular ligament: an MRI study

Aim

To describe the appearances and determine the prevalence of the meniscofibular ligament (ligamentum fibulare-MFibL) on MRI of the knee.

Subjects and methods

Retrospective observational review of 160 knee MRI studies (152 patients) which was performed for a variety of clinical presentations over a period of 31 months. The images were assessed independently by two musculoskeletal radiology Fellows.

Results

The MFibL was optimally visualised on far lateral sagittal oblique fat suppressed PDW FSE images. The MFibL appeared as a curvilinear or straight, hypointense band of variable thickness extending between the inferior margin of the posterior third of the lateral meniscus and the fibular head. The ligament was demonstrated in 42.5% (n = 68) of the total knee MRI studies, but this prevalence increased to 63% (56/88) in the presence of fluid in the posterolateral corner of the joint.

Conclusion

The MFibL is commonly seen on far lateral fat suppressed oblique sagittal PD weighted MR images, particularly in the presence of fluid in the posterolateral corner, and should be recognised as a normal structure in the posterolateral corner of the knee.     

Rectal villous tumours: MR features and correlation with TRUS in the preoperative evaluation

Aim

The aim of this study was to assess the clinical relevance of MR and transrectal ultrasonography (TRUS) imaging of rectal villous tumours to elucidate the correlation between imaging results and specific histopathological tumour features, such as tumour size (T) and lymph node involvement (N), in order to establish the better technique for the pre-surgical patient evaluation.

Patients and methods

23 cases of villous tumours of the rectum were studied with phased-array MR and TRUS. All patients underwent either surgical or endoscopic treatment. Final diagnosis was based on histopathological results. In particular, the following features were characterized by the imaging techniques mentioned above: lesion site, distance between lesion and ano-rectal junction, size, morphology and contrast enhancement of lesions, fluid layer around the lesion, alterations of the deep layers of the rectal wall, sphincter infiltration, presence or absence of mesorectal, iliac and obturatory lymphnode involvement.

Results

Histology established muscular involvement in 7 cases (T2), perirectal fat infiltration in 1 case (T3); in the remaining 15 cases, staging was Tis-T1. In 17/23 cases (73.9%) the lesions were correctly staged with both imaging techniques, whereas in 5/23 cases (21.7%) the lesions were overstaged. No cases were understaged. TRUS concorded with histological exams in 17/23 cases (73.9%). 5/23 cases (21.7%) were overstaged and 1/23 (4%) was understaged. MR and TRUS were in accordance in 20/23 cases (86.9%).

Discussion

Considering the frequent degeneration of villous tumours, correct preoperative identification and precise evaluation of these lesions, such as the detection of rectal wall invasion, is essential in deciding optimal treatment strategy. MRI and TRUS allow the identification of specific features of villous tumours and of malignant degeneration, allowing for a correct local disease staging.     

Normal cranial bone marrow MR imaging pattern with age-related ADC value distribution

Objective

To determine MRI appearances of normal age-related cranial bone marrow and the relationship between MRI patterns and apparent diffusion coefficient (ADC) values.

Methods

Five hundred subjects were divided into seven groups based on ages. Cranial bone marrow MRI patterns were performed based on different thickness of the diploe and signal intensity distribution characteristics. ADC values of the frontal, parietal, occipital and temporal bones on DWI were measured and calculated. Correlations between ages and ADC values, between patterns and ADC values, as well as the distribution of ADC values were analyzed.

Results

Normal cranial bone marrow was divided into four types and six subtypes, Type I, II, III and IV, which had positive correlation with age increasing (χ² = 266.36, P < 0.01). The ADC values of normal parietal and occipital bone marrow showed significant negative correlation with age growing (r = −0.561 and −0.622, P < 0.01), while there were no significant differences of that with age increasing in frontal and temporal bone marrow (P > 0.05). In addition, there was significant negative correlation between the ADC values and MRI patterns in the normal parietal and occipital bones (r = −0.691 and −0.750, P < 0.01).

Conclusion

The combination of MRI features and ADC values changes in different cranial bones showed significant correlation with age increasing. Familiar with the MRI appearance of the normal bone marrow conversion pattern in different age group and their ADC value will aid the diagnosis and differential of the cranial bone pathology.