What’s new in MSK Imaging – February 2021

12 months ago

 

Advanced MR imaging of bone marrow: quantification of signal alterations on T1-weighted Dixon and T2-weighted Dixon sequences in red marrow, yellow marrow, and pathologic marrow lesions

Chayanit Sasiponganan, Kevin Yan, Parham Pezeshk, Yin Xi, Avneesh Chhabra

Skeletal Radiology

Background

Radiologists interpreting MR images of skeletal lesions (or with incidental skeletal lesions) must assess signal changes in order to make a diagnosis, however data on quantitative signal changes is limited in the literature. This article assesses signal intensity of fatty marrow, hemapoetic marrow, and bone marrow lesions on MRI.

Question

Can yellow marrow, red marrow, and osseous lesions each be distinguished by signal intensity on T1 and T2 weighted Dixon images?

Study Design

Retrospective study

Participants

141 patients (77 controls and 64 with osseous lesions – 33 benign and 31 malignant) with imaging performed between January 2016 and December 2017 at a single site.

Methods

Regions of interest (ROI) were drawn within the L5 vertebral body, in the bilateral iliac bones, and in the bilateral femurs on in-phase and out-of-phase T1 and T2 weighted images. ROIs of best fit were drawn over lesions on the same sequences. Signal intensity changes in each group were compared.

Results

Smaller SI changes were seen in fatty marrow as compared to hematopoetic marrow on both T1W and T2W Dixon imaging at all locations (p < 0.0001) except at L5 on T2W Dixon imaging. Both benign and malignant lesions showed significantly smaller SI changes as compared to both yellow and red marrow on T2W Dixon imaging. Malignant lesions also notably exhibited smaller SI change as compared to benign lesions on T2W Dixon imaging. Signal intensity loss on both red and yellow marrow were smaller on T1W Dixon as compared to T2W Dixon.

Conclusion

There are significant differences in signal intensity changes on in- and out-of-phase Dixon images when comparing fatty marrow, hematopoetic marrow, and bone lesions. These differences are more conspicuous when using T2 weighted imaging. This suggests significant utility of obtaining in- and out-of-phase T2 Dixon images when characterizing marrow/osseous lesions on MR exams.

Link

https://doi.org/10.1007/s00256-019-03303-z

Senior editorial comment

This is an important work establishing the utility of T2 Dixon for marrow lesions. As a result, T2 Dixon serves as one-stop shop for internal derangement and marrow lesion characterization. It is used routinely in our practice and we do not do T1W imaging in our practice for internal derangements to save time on imaging while keeping high diagnostic accuracy. In addition, a 3-4 minute T2 Dixon or PD Dixon sequence replaces PD and PDFS for internal derangement evaluation.

Evaluation of marrow abnormalities can be a challenge and many different techniques have been used in the past. The authors demonstrate very well the utility of the Dixon technique to accentuate these differences between normal and pathological marrow.- KJ

Radiology trainee’s take home message

When characterizing an osseous lesion on MRI, Dixon in-phase and out-of-phase imaging may be useful in both accentuating the lesion due to relatively less signal drop within the lesion compared to normal bone marrow, and may be useful as one of many imaging features to support benignity versus malignancy.

T2 Dixon is the more useful in evaluation of most lesions.

 

Femoral Version in Hip Arthroscopy: Does it Matter?

Robert W. Westermann and Michael C. Willey

Sports Medicine and Arthroscopy Reviews

Background

Arthroscopic management of femoroacetabular impingement (FAI) has been substantially increasing over the past two decades. Femoral version is a variable component of FAI patient anatomy that may be less well known. Low degrees of version can contribute to anterior impingement, while high degrees of version can be seen in dysplasia and may contribute to hip instability or posterior impingement.

Question

Does careful measurement of femoral version aid in treatment of patients with FAI or hip dysplasia? What are the methods of obtaining this measurement?

Study Design

Review article/commentary

Results

Femoral version is defined as the angle between the femoral head/neck and the distal femoral condyles. The normal range of femoral version has been stated to be between 10 – 14 degrees with a standard deviation of 12 degrees.

Several radiologic methods of measurement exist, and version is most commonly assessed on CT (see Figure 1 from the article).

Because version describes the angle between the femoral head/neck and distal femoral condyles, images must include both the proximal and distal femur (without intervening patient motion) to provide accurate measurement.

Physical examination may also be useful in assessment of version, with in-toeing suggesting the possibility of excess anteversion and out-toeing suggesting relative retroversion. A trochanteric prominence test (“Craig’s test”) can be performed in the prone position with palpation of the greater trochanter as the leg is rotated and measurement of the tibia relative to the vertical axis when the trochanter feels most prominent.

Relative femoral retroversion increases the possibility of anterior femoral neck impingement (with or without cam deformity) and may influence the required arthroscopic technique for pain relief. Low degrees of femoral version also predisposis to subspinous impingement. High degrees of version may contribute to ischiofemoral impingement and may indicate need for more aggressive (non-arthroscopic) surgery in hip dysplasia for lasting results.

Conclusion

Femoral version is an important component of hip anatomy that may contribute to symptoms and surgical planning. Accurate measurement is important for pre-surgical assessment of the patient’s pathology.

Link

https://doi.org/10.1097/jsa.0000000000000299

Senior editorial comment

Thank you for a nice review. Excessive femoral anteversion in the setting of hip dysplasia requires femoral de-rotational osteotomy. Association of decreased version with ischiofemoral attachment is not clear. I personally do not believe in this diagnosis and in my practice, several patients show fatty change or increased signal of quadratus femoris muscle with no symptoms whatsoever. I have tried to inject ischiofemoral space with good technical success but no clinical success.

https://radiology.wisc.edu/wp-content/uploads/2017/11/Femoral_Anteversion.pdf

A very well explained way to measure fem version.- KJ

Radiology trainee comment

Femoral version is the angle between the femoral head/neck and the distal femoral condyles (normal 5-15 degrees).

This is commonly measured on CT in our hip preservation practice, which must include both the proximal and distal femur in order to provide a value.

Commonly used methods of measurement of the femoral head/neck angle relative to the line along the posterior distal femoral condyles are included in figure 1 of this article.

Version angles can be measured with limited cuts through the hip, knee, and ankle. These can also be measured off MRI images. Whole limb assessments are made with the evaluation of the hip, knee, and ankle rotations to make appropriate rotational corrections, either at the femoral or at the tibial levels. MK

 

Is Second Metatarsal Protrusion Related to Metatarsophalangeal Plantar Plate Rupture?

Tania S. Mann, Caio Nery, Daniel Baumfeld, Eloy A. Fernandes

American Journal of Radiology

Background

Plantar plate (PP) degeneration and tears are common causes of forefoot pain, with the second metatarsophalangeal joint (MTP) the most frequently involved due to range of motion and loading during gait. Relative length of the second metatarsal protrusion has been suggested as a predisposing factor.

Question

Does second metatarsal protrusion increase likelihood of PP degeneration and tear? If so, is there an exact degree of protrusion that significantly increases this possibility?

Study Design

Retrospective study

Participants

166 patients >18 years of age (including 211 feet) that presented for forefoot pain from March 2015 to December 2017. Mean age was 47 and 79% were women.

Exclusion Criteria

Patients with neuropathy, arthritis, diabetes, infections, or history of prior forefoot surgery were excluded

Methods

Retrospective review of imaging of the included patients was performed. Weight bearing radiographs and MR images were included for review by a musculoskeletal radiologist and a foot and ankle orthopedic surgeon. Second metatarsal protrusion length was measured (on axial images on MRI and on AP radiographs). The measurement of second metatarsal protrusion was the perpendicular distance from the apex of the 2nd metatarsal head to a line drawn between the distal 1st and 3rd metatarsal heads. Images were also reviewed for PP tear. A direct sign of complete tear is fluid signal at the PP insertion. Fibrosis, retraction, and partial/degenerative tears were also noted. Clinical findings were reviewed and statistical analysis was performed.

Results

Excellent interreader agreement was observed. MRI measurement of protrusion was highly correlated with foot radiographic measurement; however the absolute values were smaller on MRI than on radiograph (MRI measurement = 0.656 × radiographic measurement or radiographic measurement = 1.44 × MRI measurement (in millimeters)). ROC curve revealed a cutoff value for PP tear, with values of 5.5 mm on radiographs and 3.2 mm on MRI having a sensitivity of 36-53% and specificity of 68-89%.

Conclusion

This study found a significant correlation between degree of second metatarsal head protrusion and the rate of plantar plate tear, with a protrusion of 5.5 mm on weightbearing radiographs (or 3.2 mm on MRI) correlating with PP tear.

Link

https://doi.org/10.2214/ajr.19.22563

Senior editor comments:

Thank you for your work. Low sensitivity and specificity are expected given the methods used. First, MRI measurements are smaller than on X-rays, likely due to non-weightbearing effects. Secondly, the metatarsal heads are bound by curvature of a parabola. If the authors look for broken parabola due to the longer 2nd MT, it could have been a useful assessment than measurement connecting 1st and 3rd MTs. Lastly, without good clinical correlation, it could be a chicken or egg phenomenon, whether plantar plate tear leads to change in alignment of 2nd MT or the former predisposes to plantar plate tear. Nevertheless, good exploratory work.

Radiology trainee comment

Patients with increased length of protrusion of the second metatarsal have increased risk of plantar plate rupture. Protrusion was measured as the distance between the distal aspect of the second metatarsal head to a line drawn between the distal first and third metatarsal heads.

Biomechanics of the foot are significantly regulated by the second metatarsal. The second metatarsal forms the strike zone, or the bone that load bears when the foot “takes off”.

 

MRI of the Carpal Tunnel 3 and 12 Months After Endoscopic Carpal Tunnel Release

Alex Wing Hung Ng, James Francis Griffith, MD1 Chris Siu Chun Tsai, Wing Lim Tse, Michael Mak, , Pak Cheong Ho

American Journal of Radiology

Background

While there are detailed descriptions of findings in carpal tunnel syndrome, the natural course of signal changes in the median nerve and the MR appearance of the carpal tunnel after surgical release are less well characterized.  Understanding the expected appearance is important as residual or recurrent symptoms are present in up to 20% of patients after release, and up to 10% will need repeat surgery.

Question

What is the expected postoperative appearance of the carpal tunnel after release? How do signal changes in the median nerve evolve over time.

Study Design

Prospective study

Participants

32 patients (35 wrists) with carpal tunnel syndrome (CTS) diagnosed clinically and by nerve conduction studies were included in the study. 27 of the 32 patients were women and the average age was 57.

Methods

Baseline and postoperative MRs at 3 months 12 months were obtained on a 3T system. MR images were analyzed with measurements made by two musculoskeletal radiologists. Median nerve cross sectional area, caliber-change ratio (proximal and distal), flattening, and signal intensity were all measured.  Retinacular bowing, retinacular gap size, and carpal tunnel cross sectional area were also measured. Statistical analysis was performed. Clinical assessments of CTS symptoms were also performed.

Results

All patients had some relief of symptoms at 3 and 12 months. Median nerve cross sectional area proximal to the carpal tunnel, median nerve inlet caliber change, flattening ratio at the inlet were improved postoperatively. Median nerve signal intensity was also decreased at 12 months. Retinacular bowing and carpal tunnel cross sectional area were also improved over time. A retinaculum gap was seen in 94% of patients at 3 months but only 12% at 12 months. None of these parameters were associated with clinical improvement scores except for median nerve signal intensity ratio distal to the carpal tunnel at 12 months.

Conclusions

MRI imaging findings of carpal tunnel syndrome are expected to improve postoperatively, particularly at the inlet, however these findings do not significantly correlate with symptoms/clinical improvement. Median nerves also remained enlarged (despite improvement) at 12 months postoperative, even with good clinical response. Thus, while the natural course of imaging after carpal tunnel release is now described, these must be correlated with clinical findings/symptoms to be of utility.

Link

https://doi.org/10.2214/ajr.20.23066

Senior editor comments

This is a great work and establishes the fact that MRI findings lag clinical improvement. From my experience, role of MRI in follow-up of such cases is to detect worsening of nerve findings due to re-entrapment and determination of nerve injury and neurovascular anatomy in patients not improving clinically or worsening after failed surgery. The study also establishes that flexor retinaculum or transverse carpal ligament can reform after surgery due to scarring and re-ligamentization.

Radiology trainee comments

Typical imaging findings that suggest carpal tunnel syndrome include flattening, change in caliber, swelling, and hyperintensity of the median nerve, thickening/bowing of the flexor retinaculum, and effacement of the carpal tunnel fat. In the postoperative patient, many of these findings may be present at least 1 year after surgery despite improvement in symptoms, suggesting the preoperative imaging criteria for median neuropathy are less helpful in this population.

Understanding the normal postoperative appearance in carpal tunnel release helps in limiting overdiagnosis of abnormalities. Always correlate imaging findings with patient presentations.

 

Best Practices: Best Imaging Modality for Surveillance of Metal-On-Metal Hip Arthroplasty

Jonelle M. Petscavage-Thomas, Alice Ha

American Journal of Radiology

Background

Metal-on-metal hip arthroplasty may result in soft tissue complications. Imaging is essential in detection and surveillance of these adverse reactions to metal debris (ARMD) and adverse local tissue reactions, however, a review is necessary to assess the optimal imaging modality to monitor these reactions.

Question

What are the advantages and disadvantages of ultrasound, CT, and MR for detection/monitoring ARMD? Which is most commonly clinically useful?

Study Design

Review

Methods

83 articles published between December 2014 and September 2019 were reviewed for level I-IV studies (including randomized and observational studies) and excluding duplicates and studies without reference standard or sensitivity/specificity/accuracy data. MR was most commonly mentioned (54/83), while only 4 articles about CT utility were included.

Results

MRI (particularly using MARS protocol with higher bandwidth, smaller voxels, 1.5 T magnets, fast spin-echo sequences, and STIR rather than T2 fat suppressed sequences) are well described in the literature. 3D multispectral imaging has also been applied to reduce susceptibility artifact, particularly when evaluating the adjacent bone. MRI performs well in detection/monitoring of pseudotumors, synovitis, and fluid collections.

Ultrasound has the advantage of low cost, wide availability, and quick performance time, and visualization of soft tissues directly adjacent to metal, however operator dependence and difficulty visualizing deep structures are cons of the modality in this setting. In comparison studies, US and MRI both performed well with >90% sensitivity, specificity, and agreement for pseudotumors.

Finally, there is less literature for CT in this setting. CT exams do include radiation exposure, however these are generally less expensive than MRI and faster to perform than US or MRI. In some studies, CT seems to find more osteolysis and similar rates of pseudotumor compared to MRI.

Conclusions

In the setting of metal hip arthroplasty and possible ARMD, the authors recommend MARS MRI or 3D MSI MRI as first line of imaging. US offers an inexpensive exam focused on soft tissues, while CT is more sensitive to osteolysis but includes radiation exposure.

Link

https://doi.org/10.2214/ajr.19.22344

Radiology senior editor comments

Thank you for your work. MRI is the standard of care for metal related complications following a screening radiography. US is however an essential and excellent tool for interventions in these cases, such as for finding and draining collections, painful bursitis, and joint sampling for suspected infection.

Radiology trainee comments

In the setting of metal hip arthroplasty, MRI is likely the best imaging modality to pursue (with use of metal artifact reduction such as MARS protocols). CT may also be of particular use, especially if there is the possibility of osteolysis. Ultrasound is most helpful for evaluation of relatively superficial soft tissues.

Also think about the change in biomechanics and non-hip causes of pain in patients presenting with complications post total hip replacements.

 

An update on imaging of Paget’s sarcoma

William Tilden and Asif Saifuddin

Skeletal Radiology

Background

Paget disease of bone is characterized by abnormal bone turnover. The disease is usually seen in patients >60 years of age and most commonly with those of Caucasian heritage and remains idiopathic. The disease also carries a risk of malignancy arising within the abnormal bone including osteosarcoma, chondrosarcoma, and malignant fibrous histiocytoma, with approximately 1% of patients with Paget’s disease affected by malignant transformation.

Question

What are the imaging findings and clinical course of Paget sarcoma in the literature?

What mimics of Paget sarcoma should the radiologist be aware of?

Study Design

Review of the literature

Results

The most common histology of sarcoma arising in Paget disease is osteosarcoma. Secondary sarcomas most commonly arise in the pelvis, followed by the femur and humerus. Imaging findings include typical findings of an aggressive osseous lesion including cortical destruction and soft tissue mass. Pathologic fracture is seen in up to 1/3 of cases. MR allows for local staging including extent of soft tissue mass as well as extent of marrow-replacing component of the mass. Padget Sarcoma may also be first noted as a “cold” area on bone scan. PET/CT is not suggested due to at least one false negative result reported in the literature. Other malignancies and the early, lytic, phase of Padget disease may mimic sarcoma.

Conclusion

Padget sarcoma is a rare and aggressive malignancy, usually presenting with a destructive lesion and soft tissue mass. MRI is helpful in local staging as well as differenting Padget sarcoma from its mimics.

Link

https://doi.org/10.1007/s00256-020-03682-8

Senior editor comments

Thank you for nice work and case illustrations. We encounter Pagets disease cases infrequently these days, however knowledge of radiologic signs of sarcomatous transformation are important. Interestingly, in Texas, we are seeing primary adult osteosarcoma more frequently than secondary ones due to underlying Pagets disease or radiation, etc.

Radiology Trainee comments

This article is an important reminder that secondary sarcomas can occur in Paget disease. The mimics are especially useful for trainees. Paget sarcoma usually presents with an aggressive appearance on radiograph/CT and a soft tissue mass and marrow replacement on T1. Mimics typically lack these characteristics.

 

Preoperative Hounsfield Units at the Planned Upper Instrumented Vertebrae May Predict Proximal Junctional Kyphosis in Adult Spinal Deformity

Yu-Cheng Yao, Jonathan Elysee, Renaud Lafage, Michael McCarthy, Philip K. Louie, Basel Sheikh Alshabab, Karen Weissmann† Virginie Lafage, Frank Schwab, Han Jo Kim

Spine

Background

Proximal junctional kyphosis is a common complication following surgery for adult spinal deformity (ASD) and osteopenia is a risk factor. CTs are commonly done preoperatively, and having a readily available metric for measuring risk of this deformity would be useful clinically.

Question

Is there a correlation between the Hounsfield units of the upper instrumented vertebra (UIV) and the risk of proximal junctional kyphosis (PJK) postoperatively?

Study Design

Retrospective cohort

Inclusion Criteria

A retrospective review of patients who underwent surgery for ASD between May 2013 and July 2018 was performed, including both primary and revision surgeries. Patients were >18 years of age, had a posterior fusion for more than 5 levels, had a preoperative CT within 6 months prior to index surgery, and had a minimum of one year follow up.

Exclusion Criteria

Patients with incomplete medical record and/or loss of follow up were excluded.

Methods

108 patients were reviewed and 63 met criteria for inclusion in the study. Clinical data including BMI and sex were collected. Patients were classified into groups with bony proximal junctional kyphosis (caused by bone failure), non-bony proximal junctional kyphosis (caused by ligamentous/disc issues), and no proximal junctional kyphosis. Preoperative Hus of vertebral bodies at the UIV and UIV + 1) and statistical analysis was performed.

Results

Demographically, PJK and non-PJK were similar, with the overall group approximately 75% female and approximately 43% of the included surgeries being revisions. However, the mean HU values for the bony PJK group were significantly lower that that in the no PJK group. The mean HU in the non-bony PJK group was not significantly different from either ot the other groups. In particular, patients with a HU value of <120 had 5.74 times the risk of bony PJK compared to those with values >120.

Conculsion

Houndsfield units of vertebrae provides a valuable and simple look at patient’s degree of demineralization and thus postoperative risk of developing bony PJK. This is a valuable data point that can be obtained from the routine preoperative imaging that patients undergo for spinal deformity.

Link

https://doi.org/10.1097/brs.0000000000003798

Senior editor comments

Nice work! Altough osteoporosis has a lower threshold of HU on CT. Demonstration of increased risk of kyphosis with bone density<120HU is a useful finding. Correlation with patient activity level and Vit D levels, although difficult to assess in retrospective studies, would have been useful to find their effects on development of kyphosis.

Radiology trainee comments

Demineralized bone increases patient risk of developing kyphosis postoperatively after fusion surgery. Hounsfield units provide a simple measurement that can aid clinicians in determining the risk of this deformity for preoperative planning and counseling.

 

A comparison of femoral component rotation after total knee arthroplasty in Kanekasu radiographs, axial CT slices and 3D reconstructed images

Emma L. Robertson, Martin Hengherr, Felix Amsler, Michael T. Hirschmann, Dominic T. Mathis

Skeletal Radiology

Background

Relative component position in total knee arthroplasty (TKA) is an important factor for clinical outcome and significantly affects the acting forces on the knee joint. Femoral component rotation is defined by the posterior condylar axis (PCA) relative to the surgical or anatomical transepicondylar axis (sTEA or aTEA) – this is defined as the posterior condylar angle. There are various methods to measure this angle and some controversy on whether to use sTEA or aTEA for reference.

Question

Do Kanekasu radiographic measurements for rotational alignment compare to 2D CT or 3D CT reliability?

Study Design

Retrospective cohort study

Inclusion Criteria

82 consecutive knees from 78 patients who underwent primary TKA from 2004 – 2019 in the single center included.

Exclusion Criteria

History of trauma to the knee or revision surgery.

Methods

All patients underwent Kanekasu radiograph and axial 2D CT and had a completed 3D CT. Two independent raters measured femoral TKA rotation based on posterior condylar angles on Kanekasu view radiographs and 2D axial CT slices. 3D CT measurements had previously been recorded by a musculoskeletal specialized radiologist and were considered the gold standard.

Results

Inter and intrarater reliability for Kanekasu view radiographs and 2D CT measurements were excellent, however a systemic difference was found between Kanekasu view radiograph and 2D CT measurements and the gold standard 3D CT. Kanekasu view radiograph predicts the true angle in 66% of cases while 2D CT can measure the angle with 83% certainty.

Conclusion

2D-CT showed a higher correlation with 3D-CT (the gold standard) than Kanekasu measurements. If 3D-CT is available, it should be preferred over 2D-CT and radiographs for femoral component rotation measurement.

Link

https://doi.org/10.1007/s00256-020-03702-7

Senior editor comments

Nice work defining femoral prosthesis anatomy on radiographs and CT imaging! It is however not clear how much angular variation is acceptable clinically and what is the threshold of abnormal rotation that impacts patient symptoms or failure of TKR.

Radiology trainee comments

Femoral component rotation is an important and under recognized factor that may contribute to patient pain after TKA. Radiology trainees should be aware of how to measure this in order to provide valuable information to the orthopedist. Orthobullets has a thorough but simple explanation of optimal positioning.

https://www.orthobullets.com/recon/5017/tka-patellofemoral-alignment

Try to identify the trans epicondylar region on the distal femur on all post op knee CT to evaluate a TKA. This is what the orthopedic team is gauging in trying to evaluate the TKR for any femoral rotation. This is also important for any revision TKA procedures.

 

Li-Fraumeni Syndrome and Whole-Body MRI Screening: Screening Guidelines, Imaging Features, and Impact on Patient Management

Nikita Consul, Behrang Amini, Juan Jose Ibarra-Rovira, Katherine J. Blair, Tanya W. Moseley, Ahmed Taher, Komal B. Shah, Khaled M. Elsayes

American Journal of Radiology

Background

Li-Fraumeni syndrome (LFS) is a rare autosomal-dominant inherited syndrome containing a germline mutation in the TP53 gene, which predisposes to oncogenesis, with 41% of patients developing tumors by 18 years of age. Leukemia and tumors of the brain, soft tissues, breasts, adrenal glands, and bone are the most common cancers associated with this syndrome. Patients with LFS are very susceptible to radiation, therefore the use of whole-body MRI is recommended for regular cancer screening. It is important to recognize the common tumors associated with LFS on MRI, and it is also important to be aware of the high rate of false-positive lesions.

Question

What are the most common tumors and their imaging appearances in LFS?

Study Design

Review article

Results

LFS patients have a variety of tumors. Approximately 13% develop brain tumors such as choroid plexus carcinomas and gliomas including astrocytomas, oligodendrogliomas, and glioblastoma multiforme.  All of these are best assessed with MRI. Approximately 27% of LFS patients will develop soft tissue sarcomas, most commonly rhabdomyocarcomas followed by liposarcomas and pleiomorphic sarcomas. These are all heterogeneously or homogeneously T2 hyperintense and demonstrate avid enhancement, readily apparent on MRI. 60% of LFS patients will also develop breast cancer, which is more common before menopause and more commonly bilateral in this population. They are also at a higher rate of post-radiation malignancies after treatment. Breast cancer may present as non-mass or mass-like enhancement on post contrast T1-weighted images. 13% of these patients will also develop adrenocortical carcinoma, most commonly as a child, a tumor that demonstrates heterogeneous enhancement and intrinsic T1 and T2 hyperintensity with intratumoral necrosis, hemorrhage, and calcifications. Osteosarcoma is also seen in 16% of TP53 carriers, and often demonstrate heterogeneity on T1- and T2-weighted images and usually restrict diffusion. Leukemia is found in approximately 4% of this population and often demonstrates mild T2-hyperintensity and T1 hypointensity in bone marrow. Lesions in the skin, arms, colon, or small abnormal lymph nodes may lead to false negative whole-body MR exams. False postitives could be seen with red marrow or incidental lesions such as those in the liver, kidney, or thyroid. In-and-out of phase imaging to minimize the misinterpretation of hemapoetic marrow and incidental lesions could be followed/characterized by further, dedicated imaging.

Conclusion

LFS patients are the optimal patient population to benefit from MRI given their high incidence of tumor occurance and higher risks from radiation exposure. MRI may detect early leukemia, sarcomas, intracranial tumors, and breast cancer, however it is important for the interpreting radiologist to understand conditions it may underestimate/not detect (skin or colon malignancies) and how to manage incidental findings.

Link

https://doi.org/10.2214/ajr.20.23008

Senior editor comments

Pretty images and a great review! LFS is becoming a common indication for WBMRI apart from its use for multiple myeloma and neurocutaneous syndromes, such as neurofibromatosis and schwannomatosis. One should however note that breast cancer and brain masses are best assessed with focused high-resolution imaging in the event of detection of a potential malignant lesion in these organs on screenign WBMRI.

Radiology trainee comments

LFS is a genetic condition that predisposes patients to a variety of malignancies. This article provides a great review of the lesions that radiologists should monitor for when evaluating these patients by screening whole body MRI including sarcomas, intracranial lesions, breast cancer, and leukemia.

References
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