Bucket Handle Meniscal Tear-MRI

"The double PCL sign is associated with bucket-handle tears of the medial meniscus that occur in the presence of an intact anterior cruciate ligament (ACL). A bucket-handle tear is a longitudinal tear of a meniscus that results in a displaced but attached meniscal fragment. . The fragment may become displaced into the notch between the PCL and the medial tibial eminence in the midline, with the fragment orientated parallel to the PCL." Reference- November 2004 Radiology, 233, 503-504.

In our case of running injury this sign is well seen on the sagittal images and confirmed on coronal images.

Intraventricular oligodendroglioma

Findings:

Figure 1: Non-contrast CT shows a large rounded mass in the lateral ventricles with intermediate density and large foci of calcification within it. This is causing significant hydrocephalus with enlargement of the third ventricle.


Intraventricular oligodendroglioma


Oligodentrogliomas are well differentiated, slowly growing but diffusely infiltrating cortical and subcortical tumors. Although most of them involve the frontal and frontotemporal cortex, a small proportion of them are seen in the ventricular walls (1-10%), cerebellum and exceedingly rarely within the brainstem, spinal cord and leptomeninges. No age is exempt and the peak incidence is in the 4th or 5th decades. It usually have a long standing history of symptoms and the most common being seizures and headaches.

Intraventricular oligodentrogliomas can present with hydrocephalus. Pathologically, they are well defined, grayish-pink soft unencapsulated mass and calcification is extremely common. Focal cystic degeneration and hemorrhage are frequent findings. CSF seeding is uncommon. Histopathologically, these are moderately cellular tumors with occasional mitosis. Perinuclear halos or the "fried egg artifact" is a distinctive feature of oligodentroglioma. Majority of the "intraventricular oligodentrogliomas" described in the literature are central neurocytomas and immunohistochemistry helps to distinguish them.

On CT, oligodentrogliomas usually have mixed density with nodular, clumped or linear tumoral calcification seen in majority (50-90%). Cystic degeneration is common. Intratumoral hemorrhage and edema is uncommon. The hemispheric lesions may expand, remodel or erode the calvarium. Enhancement is variable. On MR, oligodentrogliomas are typically heterogeneously hypointense or isointense to grey matter on T1 and heterogeneously hyperintense on T2 and FLAIR due to calcification, cystic change and hemorrhage. Nearly 50% show heterogeneous enhancement following contrast administration. Areas of calcification and hemorrhage demonstrate "blooming" on gradient echo MR sequences. No diffusion restriction on DWI.

Surgical resection is the primary treatment of choice. Radiation therapy and chemotherapy is reserved for recurrent tumors. Local recurrence is common and hence regular surveillance is recommended.

Post Spinal Anesthesia Syrinx-MRI

This is 25 year old who was operated for appendicitis in the peripheral centre followed by right sided monoparesis. MRI revealed focal syrinx-myelomalacia at D11-L1 levels towards right side. Attempting to use higher lumbar intervertebral spaces for access to the subarachnoid space or epidural space may lead to inadvertent puncture of the lower dorsal spaces; this makes the procedure of spinal anesthesia at this level prone for spinal cord injury, with subsequent risk of development of myelomalacic syrinx in the conus and epiconus region of the spinal cord.

Pigmented Villonodular synovitis (PVNS)

30 yr old young lady with non specific pain knee joint.  MR shows well defined regular, intensely enhancing heterogenously altered signal intensity  lesion anterior to hoffas pad with presence of haemosiderin and  no bone involvement -  focal variety of PVNS is likely. Case submitted by Dr MGK Murthy and Dr Akshay Sahoo.

 Pigmented Villonodular synovitis (PVNS)

 Teaching points
Definition: benign proliferative disease of the synovium  affecting joints, bursae, and tendon sheaths(called giant cell tumour of tendons sheath)

Clinical: pain/ restricted  movements

Types: diffuse-common(Shag carpet type or fern like proliferation of synovium) ,  and rarer focal nodular form(sessile or pedunculated with no true capsule), usually monoarticular, knee (80%) , focal -small joints of hands and feet (commonest  soft tisue tumour of hand)

Xray---soft tissue swelling, no calcification, subchondral  saucerised erosions
CT- hyperdense (haemosiderin), enhancement
MRI- Modality of choice--- soft tissue enhancing swelling , crossing joints with no involvement of articular margins, haemosiderin on gradient sequences, subtle bright on T1 due to lipid laden macrophages and fat, secondary degeneraive changes

Paget's Disease of Bone

This patient aged 70 years male with history of CABG and bone pains exhibits cotton wool appearance, widened diploae, coarse trabecular pattern of the left femur, not so classical picture frame of L2 vertebral body, nonhomogenous presentation of left sacral ala. Diagnosis- Pagets disease of the bone

Case Submitted by-Dr UV Krishna Murthy and Dr MGK Murthy.

About Pagets disease- 3 to 4 % of the general population above the age of 40 years is expected to harbour the disease. Highest incidence is in the 7 and the 8 decades with male preponderance.  There is genetic predisposition to the disease with other theories of etiology being viral ( paramyxoma virus ) / Autoimmune / Vascular / Connective tissue disease / Metabolic ( parathormone abnormality ) / truly neoplastic. The basic defect is excessive and abnormal remodeling of the bone. Clinically varies from being asymptomatic to bone pains, fractures, anemia, expansion of the bones particularly with reference to craniofacial ( in India, manifesting as frequent changing of the spectacles frames ).

Radiological Findings

Skeletal survey continues to be the number one diagnostic parameter.  Skull 25-65%, spine 30-75%, pelvis 30-75%, proximal long bones 25-30% involvement.

  Depends on the stage of presentation

a)      Lytic ( Incipient – Active ) – Gross Destructive, Expansile, radio lucency of the region with advanced wedging of osteolysis demonstrating chronic sharp margin without sclerosis ( Blade of grass sign )

b)      Mixed ( Active ) - Coarse thickening of the trabecular and the cortical pattern with enlarging of the bone, with areas of new bone formation, with possible incremental fractures and cotton wool appearance of the skull.

c)      Blastic ( late inactive ) – Predominantly new bone formation.

    Nuclear Scintigraphy – Shows hyperactivity in all the phases. CT is more demonstrative of the plain radiographic findings.   MR is good for differentiating and excluding sarcomatous transformation ( 1% of the cases ) – Is reflected as focal bone destruction through the cortex, with the breach and invading the neighboring the soft tissues

Ewing sarcoma of the occipital bone

Findings

Figure 1: Unenhanced CT shows a heterogeneous attenuation mass with cystic spaces in the posterior fossa.
Figure 2: Intense enhancement is noted after contrast administration.
Figure 3: Bone window section showing permeative destruction of the left occipital bone.
Figure 4: Axial T1 weighted image showing extra- axial mass with multiple cystic spaces.
Figure 5: Coronal T2 image showing the extra-axial origin clearly with mass effect on the cerebellum. The cystic spaces appear hyperintense.
Figure 6: Axial T1 weighted image showing intense enhancement of the mass.


Diagnosis: Ewing sarcoma of the occipital bone


Ewing sarcoma is a small round-cell tumor arising from mesenchymal cells. These tumors affect children and young adults in the age group of 5-15 years. The long bones, flat bones like the scapula and the vertebrae are the most common sites. Primary Ewing sarcoma affecting the calvarium is extremely rare, making just 1% of the cases. In the skull, the tumor more often arises from the frontal and parietal bones and less common locations include ethmoid, temporal and occipital bones.

CT scans (bone window) reveal poorly marginated permeative destructive lesion involving both inner and outer tables of the skull. The "onion peel" appearance typical of Ewing sarcoma in long bones is not seen commonly in the calvarium. The extra-dural soft tissue shows intense enhancement on contrast administration.

MR imaging provides better soft tissue delineation of these tumors. The extra dural soft tissue appears hypointense on T1 weighted images while the cystic and necrotic areas appear hyperintense on T2 weighted images. Good contrast enhancement is noted.
The differential diagnosis should include rhabdomyosarcoma, metastatic neuroblastoma and lymphomas.

Treatment is surgery followed by chemotherapy and radiation.

Osteitis Condensans ilii-MRI

32 years multiparous lady with complaints of pain SI joints location ( left > right ) with pain involving the hip joint as well with clinically positive compression test for SI joints. MR shows diffuse pyriform areas of low signal intensity  juxta articular lesions involving both iliac bones symmetrically in the lower 2/3^rd with focal fatty marrow changes of the juxta articular sacral alae, with no widening, asymmetry, destruction, marrow edema, soft tissue collection. The features are highly suggestive of Osteitis Condensans ilii

Case by Dr MGK Murthy, MD, DNB

Teaching points:

1. It is predominantly found in women usually after child births.
2. It is often seen in young people, bilaterally and symmetrically with  general prevalence of 1.6 to 3 percent.
3. Sacral involvement is not noted.
4. Unilateral types are uncommon but noted.
5. The etiology is possibly due to laxity of the ligaments in pregnancy, leading to subtle malalignments and fibrous tissue proliferation with stress response with increase osteoblastic activity with some authers suggesting increase density of trabeculations.
6. Clinically the compression test for  sacro-iliac tenderness is likely to be positive amongst few people. However not associated chronic back pain or disability.
7. Marrow edema / Radiological malalignment / destruction / soft tissue collection is most uncommon.
8. All the other varieties of sacro-ilitis particularly the ankylosing spondylitis would show some marrow edema, ill definition and subchondral erosions.
9. Chest X-ray, serological evaluation particularly with reference to HLAB27, X-ray / CT sacro-iliac joints along with contrast MRI and if needed bone scan would play useful role.

Kropek

Kropek (or kropeck), photographed above, is a very common Pinoy snack that has stood the test of time. It is a fish or prawn cracklings (mixed with flour) that have been dried in the sun and deep fried. The Star brand pack consists of around 20 pieces of rectangular-shaped kropek cracklings. There is another variety, though, the oval-shaped one that is slightly a bit thinner but same delicious taste.

In one sitting, I could eat one pack of this kropek, especially if I sink each of its contents in a small bowl of sukang maanghang. When I was a kid, a piece of kropek was 10 centavos (one pack would be around 2 pesos). No one sells it by the piece now, however, as it is usually sold in one pack for ten pesos. The sukang maanghang is always free, though. Back then, one pack of kropek would be an ideal snack while watching the Crispa-Toyota games in our old Black and White TV set. Or perhaps a snack while reading Tagalog Klasiks or Aliwan Komiks.

I think every Pinoy must have had acquired a taste of this ubiquitous snack, especially as it is sold in every street corner by our same Balut vendor. In Sari-sari stores, the kropek is among the bestsellers, especially on Sundays, when many Pinoy istambays, hard of cash, prefer it as pulutan with the Tanduay, over the slightly more expensive chicharong baboy.

With the numerous arrivals of foreign-branded snacks like Pringles or Pik-nik, I still prefer the lowly kropek, especially if paired with a bottle of Cosmos or Mirinda. Although some older people would have preferred a sarsaparilla.

PGI Nov 2010-Radiology Recalled Questions

Few Radiology  recall questions from PGI Nov 2010 examination.



Metastases to bones is infrequent in
1. Spine
2. Proximal long bones
3. Hands and feet
4. Not recalled
5. Pubic bones

Answer- Hand and Feet.  Secondaries distal to the knee and elbow are uncommon. Only three tumours BBC, Bronchus, Bladder and Colon may show secondaries to small bones of hand and feet. Spine, proximal long bones and flat bones are marrow containing areas in adult skeleton, so metastatis is common in this bones.

Bare orbit is seen in
1. Neurofibromatosis
2. osteomyelitis
3. Metastasis
4. Meningioma
5. Hemangioma

Answer 1, 3, 4.
Bare orbit appearance is seen in the NF due to sphenoid dysplasia, Mets due to destruction and meningioma due to sclerosis. Reference -Chapman's Differential diagnosis book.

Heterotopic ossification is seen in 
1. Gout
2.  Revision surgery
3. Reiters
4. prolonged surgery 
5. Forresteir disease

Answer- All

Isotope in external beam therapy
1. cs 137
2. co 60
3. radium 226
4. I-131
5. iridium

1, 2, 5.

Screenin of prostate ca.
1. transrectal usg
2. digital exam
3. PSA
4. Not recalled
5. ct scan

Answer 2, 3. CT scan has not role in diagnosis of prostatic malignancy.

Choanal Atresia-CT

There is evidence of retained secretions in the bilateral nasal cavities with fluid level in both nasal cavities more on the right side. Also noted is thickening of vomer which measures 0.4cm, posterior nasal apertures measure 0.13cm on the right side and 0.15cm on the left side.  There is bowing and thickening of the posterior medial maxilla. Findings are consistent with choanal atresia.

Reference- CT criteria for choanal atresia include  narrowing of the posterior choanae (LWNC-V < 0.34 cm in newborn), medial bowing and thickening of the posterior medial maxilla (which may be fused with the lateral margin of vomer), thickening of vomer (>0.34 cm) and retained fluid in the nasal cavity.

Post Traumatic Rupture of Arachnoid Cyst-CT

Arachnoid cysts are a well-recognized benign intracranial lesion occuring most commonly in the middle cranial fossa. Spontaneous and post-traumatic intracystic and subdural haemorrhage has also been reported. This is case of young girl with minor trauma resulting in subdural rupture of the arachnoid cyst.  Arachnoid cysts derive from the meninx primitive, embryologically, which is the primitive membrane ensheathing the developing central nervous system (CNS). As subarachnoid CSF accumulates, this meninx cavitates and resorbs under normal circumstances leaving only the subarachnoid space and the arachnoid membrane. During this process, the arachnoid membrane may split with secretion of fluid by the arachnoid cells into the resulting cleft ultimately yielding a cyst – the so called arachnoid cyst – which is truly intra-arachnoid anatomically. 

Suprasellar arachnoid cyst

Findings:

Figure 1, Figure 2 and Figure 3 show severe hydrocephalus involving the lateral and third ventricles.
Figure 4, Figure 5, Figure 6, show a suprasellar mass lesion which follows CSF signal on all sequences, including FLAIR.


Diagnosis: Suprasellar arachnoid cyst


Arachnoid cyst is the most common congenital lesion of the brain. It is typically an incidental imaging finding and is rarely symptomatic. However, in this case the size and location of the lesion in the suprasellar cistern resulted in severe obstructive hydrocephalus and precocious puberty. Both of these complications resolved following surgical drainage of the cyst.

Arachnoid cysts arise from a splitting of the arachnoid membrane with formation of a cyst wall consisting of fibrous connective tissue. There is no epithelial lining in the wall. Expansion occurs following trapping of cerebral spinal fluid through defects in the cyst wall. Arachnoid cysts occur most commonly in the middle cranial fossa and have a 4-to-1 male-to-female ratio. Even large cysts tend to be asymptomatic. Associated clinical features in symptomatic patients include headache, calvarial bulging, intracranial hypertension, craniomegaly, developmental delay, visual loss, precocious puberty, and seizures. Treatment of arachnoid cysts is not recommended by many unless there is a clear cause and effect relationship between the cyst and symptoms as shown in this case.

MRI is the preferred diagnostic modality for arachnoid cysts because of its ability to demonstrate the location, extent and relationship of the cyst to surrounding neurologic structures. Lesions typically have the signal intensity of CSF on all sequences, do not enhance and do not demonstrate restricted diffusion. The most important differential diagnostic consideration is between arachnoid and epidermoid cysts. Epidermoid cysts show restricted diffusion on diffusion-weighted images. In addition, unlike epidermoid cysts, arachnoid cysts show suppressed signal on fluid-attenuated inversion recovery (FLAIR) images.

Possible Rassmussen's Encephalitis-MRI

Rassmussen's Encephalitis is also known as Hemiconvulsion-Hemiplegia Epilepsy. This is 9month oldinfant with fever, convulsion and one sided weakness. On MRI left sided hemisphere is swollen and shows white matter hyperintensity confined to one hemisphere well seen on DWI possibly indicating cytotoxic edema. This appearance may indicate early stage of rassmussen's encephalitis and may progress to hemiatrophy. Further follow up was advised.

Gynecological MRI- Two Cases

These are two cases that were referred to Teleradiology Providers ,  one is 55 year old lady with ca endometrium with myometrial invasion more anteriorly and involvement of cervix. Other case is lady with pedunculated lower uterine segment fibroid seen arising from the anterior myometrium with is seen hanging in endocervical and endovaginal cavity.

Malignant melanoma of the uvea

Findings

Thin section axial fat-suppressed fast spin-echo T2-weighted imaging
Figure 1 and Figure 2 show a V-shaped retinal detachment pointing toward the optic nerve. There is increased T1 signal posterior to the detachment suggesting hemorrhage.

Thin section axial fat-suppressed T1-weighted imaging
Figure 3 and Figure 4 show a mass arising from the nasal aspect of the right ocular globe. There is a collar button configuration to this mass, which assumes the typical configuration strongly suggesting elevation of Bruch’s membrane. The mass is near isointense to muscle on precontrast T1 and T2 weighted images. This mass extends towards the vitreous but no extension beyond the sclera is identified.

Postcontrast fat-suppressed T1-weighted imaging
Figure 5 and Figure 6: The mass is near isointense to muscle on pre-contrast T1 and T2 weighted images and demonstrates prominent contrast enhancement.


Diagnosis: Malignant melanoma of the uvea


Uveal melanoma is the most frequent primary intraocular malignant tumor in adults. It is rare in children. Its importance is that it is the main intraocular disease that can be fatal in adults.
Uveal melanoma can erupt through Bruch's Membrane. When this occurs, they develop a characteristic collar button configuration that extends through the vitreous chamber.
Uveal melanomas have differing MR characteristics, depending on the amount of melanin, which has paramagnetic properties. Melanomas containing a lot of melanin will demonstrate T1 hyperintensity, and markedly decreased T2 signal. However, in amelanotic or slightly melanotic melanomas, the typical MR pattern is isointense on T1, and slightly hypointense on T2.

Uveal melanoma is the most frequent form of intraocular malignancy in adulthood (4). As the uvea is the most vascular region of the globe, it is a common site for primary and metastatic neoplasm. Uveal melanomas comprise 70% of malignant intraocular tumors. It affects approximately 5-7 out of 1,000,000 people (3). Uveal melanoma can occur in any of the three subdivisions of the uvea: the iris, ciliary body, and choroid.

Uveal melanomas start with a flat growth profile along the choroid. With progression, they become elevated, and frequently extend through Bruch's membrane, where they can track into the subretinal space. With spread through Bruch's membrane, the melanoma can have a "mushroom shape" or "collar button" appearance that extends through the vitreous chamber.

Uveal melanomas typically appear as a solid, well-defined mass on magnetic resonance imaging. Melanin is paramagnetic, so in melanomas containing a lot of melanin, there is increased T1 signal with markedly decreased T2 signal. This signal intensity pattern is pathognomonic for uveal melanoma, as there are no other intraocular lesions with this appearance. In low-melanin or amelanotic melanomas, Magnetic Resonance imaging is less specific, but typically shows isointense signal on T1-weight images and slightly hypointense signal on T2-weighted images. Uveal melanomas typically have moderate to strong contrast enhancement following administration of gadolinium.

B-mode ultrasound typically shows a rounded, hypoechoic, highly vascular lesion. Retinal elevation and vitreous hemorrhage can also be seen, as these are complications of uveal melanomas. Uveal melanomas on unenhanced computed tomography appear sharply marginated, hyperattenuating, and elevated.

Uveal melanomas also have a propensity to metastasize hematogenously, and do so most frequently to the liver. Uveal melanoma is the most common fatal intraocular disease in the adult population.

Optimal treatment for uveal melanomas is controversial and clinical trials are ongoing. Large melanomas, typically greater than 10-mm in thickness, are usually managed with enucleation. For medium sized melanomas, 3-mm to 10-mm thick, plaque brachytherapy and external-beam radiation therapy have been accepted as alternatives to enucleation. For small lesions, less than 3-mm, routine monitoring with ultrasound is recommended as these may represent benign choroid nevi. These small lesions may also be biopsied, with a positive result placing the small melanomas into the medium melanoma treatment category.

Prognosis is dependent on many factors. Increasing tumor pigmentation is associated with a less favorable prognosis. Additionally, increasing size, infiltration through Bruch's membrane, and retinal detachment are all associated with a poorer prognosis. In metastatic disease to the liver, the mean survival has been reported to be nine months.

Posterior Limbus Vertebrae-MRI

Limbus vertebra develops in the immature skeleton due to focal herniation of the disc through the vertebral endplate, isolating fragment of the peripheral secondary ossification center (ring apophysis). The majority involves the anterior margin of the endplate, although posterior limbus veretbrae are not exceedingly rare. Posterior involvement may have neurological implications due to compression and/or inflammation of nerve roots.

Pulmonary Embolism-Spiral CT

Pulmonary embolism (PE) was clinically described in the early 1800s, and von Virchow first described the connection between venous thrombosis and PE. This image shows an intraluminal filling defect that occludes the left pulmonary artery. Also present is an infarction of the corresponding lung, which is indicated by a triangular consolidation and pleural effusion.

Sternoclavicular Joint Tuberculosis-MRI

The occurrence of tuberculosis in the flat bones of chest and skull is very rare. With the resurgence of tuberculosis all over the world, there have been reports of unusual sites being affected by the disease. However, cases of clavicular or sternoclavicular tuberculosis are few. The rarity of occurrence of tubercular arthritis of the sternoclavicular joint can be attributed to the peculiar blood supply of this joint. The common conditions, which have to be differentiated from sternoclavicular tuberculosis are low grade pyogenic infections, rheumatoid disease, myeloma or secondary deposits. This is confirmed case of tuberculosis in a 46year old Indian male.