Differential diagnosis in Radiology

Checklist: Post Rx imaging of head and neck cancers

2011-01-19T11:41:00.001Z

Clinical information:
Histopathology:
TNM staging:
Surgery: Radical/ modified radical neck dissection, laser, no surgery
Reconstruction surgery: yes/ no
If yes, flap details:
Radiotherapy: yes/ no
If yes, type of radiotherapy

Primary site review:
Residual disease/ recurrence/ post-op change
Radiation induced sarcoma: latent period is 5 years, radiation induces SCC, lymphoma and meningioma

Post RT changes:
Acute post-RT changes (within 2-4 weeks): skin, platysma, neck space edema, enhancing salivary glands, enhancement of mucosal lining, increased attenuation of paralaryngeal fat
Subacute post-RT changes (few months to 18 months): chronic mucositis (polyps), chronic sialadenitis, i.e, loss of volume (virtually in ALL), especially parotids, fibrosis (may or may not enhance, stop enhancing after 18 months), persistent reactive nodes

Radionecrosis:
Sites: larynx, mandible, temporal bone, basisphenoid, maxillary bone
6- 15 months
Sclerosis, fragmentation, mottled appearance, sloughing, break of cartilage and bone with sequestration, pathological fracture, loss of trabeculae. Subluxation/ dislocation (of arytenoids). Soft tissue thickening, abscess, fistula, gas in the soft tissue. Enhancement of the adjacent muscles and fat.

Neurological changes:
Radiation cerebral necrosis: Deep white matter of medial and inferior temporal lobes or frontal lobes (depending on site of RT)
Brainstem encepahlopathy, myelopathy and transverse myelitis
RT induced brachial plexopathy
Traumatic neuroma
Denervation od V, XI and XII nerves

Reference:
Post-treatment imaging appearances in head and neck cancer patients

Staging Sarcoidosis

2010-04-08T15:39:00.001+01:00

CXR:
Stage 0: normal
Stage 1: hilar and/or mediastinal lymphadenopathy (resolve in 65%)
Stage 2: hilar and/or mediastinal lymphadenopathy and visible lung disease (resolve in 50%)
Stage 3: Lung disease only (resolve in 20%)
Stage 4: End stage fibrosis (irreversible)

Interstitial lung disease: Simplified approach

2010-03-25T16:55:00.001Z

Most common ILD: idiopathic interstitial pneumonia (idiopathic pulmonary fibrosis). Always keep sarcoidosis in the differential, before you are fairly sure of other diagnosis. Few ILDs have characteristics (or even pathognomonic) features, although they are rare. Othe rare ones with no typical HRCT features are rare, who cares?

HISTORY:
Get the clue from history, which is unfortunately seldom given on the radiological request form. Dig the history from clinical notes. Clinicians seldom give this information to radiologists.

Exposure related:

Smoking: look for respiratory bronchiolitis-related ILD

Occupuation related:

Farmer: hypersensitivity pneumonitis

Medication related:

Many drugs cause ILD. Refer books if you find long term medication of any drugs to see if they cause ILD.

Connective tissue disorder, arthropathies, inflammaroty bowel disease:

If the referral has come from rheumatologists, the patient is likely to have at lest suspected connective tissue disorder.

Characteristic HRCT features:
Sarcoidosis: bilateral symmetrical mediastinal and/or hilar lymph nodes and/or fissural beading
Asbestosis: calcified and non-calcified pleural plaques with bibasal ILD
Lymphangioleiomyomatosis/ tuberous sclerosis: child bearing woman with numerous diffuse cystic areas!
Pulmonary alveolar protenosis: diffuse mosaic ground glass crazy paving pattern without fibrosis.
Chronic hypersensitivity pneumonitis: UIP pattern with centrilobular nodules, sparing the lung bases

Typical patterns in CTDs:
Most common pattern in CTD: NSIP, next UIP
Rheumatoid arthritis: UIP, less common - NSIP
Scleroderma/ systemic sclerosis: fibrotic NSIP
Polymyositis: NSIP or organising pneumonia
Sjogren's: LIP
Dermatomyositis/ polymyositis: NSIP, less common - organising pneumonia
Mized collagen vascular disorder: NSIP

Diagnosis to be considered in a smoker:
Never miss a lung tumor on HRCT!
Histiocytosis: centrilobular fine nodules of 1-10mm and cysts in upper zones with relative sparing of lower zones. Stop smoking = good prognosis
RB-ILD:
Histopathological diagnosis on HRCT!:
UIP/ IPF: Bibasal zones peripheral reticulation, honeycombing, fibrosis. Ground glass is less than reticulation. UIP pattern is seen in asbestosis, CTD (especially RA), drug toxicity, sarcoid, chronic hypersensitivity pneumonitis (centrilobular nodules and sparing of bases)
NSIP: Bibisal peripheral symmetric ground glass opacity. Honeycombing uncommon.
COP: Non-smokers more than smokers! subpleural, peribronchial and/or perilobular consolidation. Air bronchogram. ground glass opacity. Smooth well defined "reverse halo" nodules (reverse halo is also seen in Wegeners').
AIP: patchy bilateral anteroposterior increasing ground glass opacity with lobular sparing. Looks similar to ARDS, but clinically not.
RB-ILD: Occurs always in smokers. Cntrilobular nodules, pathcy ground glass, bronchial wall thickening, with added centrilobular emphsema.
DIP: Rare. Common in smokers. Bilateral ground glass predominantly mid and lower zones. Reticulations and honeycombing may be seen.
LIP: a/w Sjogren's, PBC. Bilateral groound glass, thin preivascular cysts, centrilobular nodules, mild reticulations.

Reference:
1. Interstitial lung disease, Seminars in roenthenology volume 45, no 1

Diffusion weighted images

2010-03-24T13:59:00.001Z

Basics:
Bright signal on DWI (B=1000) means restricted diffusion and/or T2 effect.
On ADC, low signal in the same region means restricted diffusion, and bright or isointense signal means T2 shine through effect.
On T2, the same area may appear bright or isointense.

Pathologies with restricted diffusion:
Acute stroke, acute stroke, acute stroke... (repeat this 10 times before proceeding to next)
Infection: Herpes encephalitis, Pyogenic infection, CJD, meningoencephalitis
Epidermoid (ADC usually cannot be calculated)

Diffuse axonal injury
Oxyhemoglobin (intracellular and hyperacute) (extracellular methHb shows increased signal on both DWI and ADC!)

A few acute MS lesions
Post-ictal
Susceptibility artefact: in inferior frontal and temporal regions should not be mistaken for restricted diffusion

Non-restricted diffusion:
Infection: HIV encepahlopathy
Tumor: primary or secondary, arachnoid cyst
Inflammation: most acute MS lesions
Chronic lesions: chronic stroke, gliosis, neuronal loss
Others: hypertensive encephalopathy, clyclosporin toxicity, hyperperfusion after endartertectomy

List of diseases involving Hoffa's fat

2010-03-19T10:40:00.000Z

Hoffa's disease
Intracapsular chondroma
Localized nodular synovitis
Post artthroscopy fibrosis
Shear injury
Intraarticular loose bodies
Meniscal cyst
Ganglion cyst
Cylops (arthrofibrosis)
PVNS
Hemophilia
Synovial hemanagioma
Synovial chonromatosis
Lipoma arborescens
Synvoial proliferation in inflammatory arthritis

Stable vs unstable fracture of the vertebrae

2010-03-16T10:13:00.000Z

Unstable:
neurologic deficit
loss of 50% of vertebral body height
fracture dislocation
angulation of the thoracolumbar junctionmore than 20 degree
canal comprimisemore than 30 percent

Stable:
neurologically intact
posterior arch remains intact

RECIST criteria simplified

2010-02-09T10:56:00.001Z

Measurable lesion:
o Presence of at least one measurable lesion, at least10 mm on spiral CT, or 20 mm on other techniques

Non-measurable lesion:
o less than 10 mm on spiral CT, 20 mm on other technique
o bone lesions
o leptomengeal disease
o ascites, pleural and pericardial effusion.
o Lymphangitis carcinomatosa
o Cystic lesions
o Abdomen masses

Target lesions (TL):
o All measurable lesions up to maximum of 5 per organ or 10 in total
o Selected on basis of size and reproducibility
o Sum of fall target lesions (longest diameter) is taken as baseline sum

Non target lesions (NTL):
o No measurement is required, but noted.

New lesions:
o All new lesions should be noted

Response criteria:
• Target lesions:
o CR: Complete response: Disappearance of all target lesions
o PR: Partial response: At least 30% decrease in the sum of target lesions
o PD: Progressive disease: At least 20% increase in the sum of target lesions
o SD: Stable disease: No change
• Non-target lesions:
o CR: Complete response: Disappearance of all non-target lesions
o SD: Incomplete response/ stable disease: Persistence of non-target lesions
o PD: Progressive disease: new lesions/ unequivocal increase

Evaluation of overall response:
• CR: complete response
o TL CR, NTL CR, no new lesions
• PR: partial response
o TL CR, NTL SD, no new lesions
o TL PR, NTL non-PD, no new lesions
• SD: stable disease
o TL SD, NTL non-PD, no new lesions

• PD: progressive disease
o TL PD, any, + new lesions
o TL any, NTL PD, + new lesions
o TL any, NTL any, new lesions

Grading subarachnoid haemorrhage

2009-12-30T10:41:00.000Z

CT grading: Fischer scale:
Grade 1: No clot seen on CT scan
Grade 2: Diffuse thin layer of SA clot (less than 1mm thickness)
Grade 3: Localised clot or thicker layer of SA clot (more than 1mm thickness)
Grade 4: Intracerebral or intraventricular clot with diffuse or no SA clot

Hunt and Hess grading system:
Grade 1: Asymptomatic or mild headache
Grade 2: Moderate-to-severe headache, nuchal rigidity, no neurological deficit other than cranial nerve palsy
Grade 3: Mild altered mental status (confusion, lethargy), mild focal neurological deficit
Grade 4: Stupor, hemiparesis
Grade 5: Comatose and/or decerebrate

WFNS (World federation of neurological surgeons) scale:
Grade 1: GCS 15, no motor deficit
Grade 2: GCS 13-14, no motor deficit
Grade 3: GCS 13-14, motor deficit +
Grade 4: GCS 7-12, motor deficit +/-
Grade 5: GCS 3-6, motor deficit +/-

Renal cysts: Grading

2009-12-19T13:38:00.002Z

Bosniak 1:
Simple cyst, anechoic on US and water density ( less than 10HU) on CT, imperceptable (hairline) wall, rounded, no calcification, no septation, no enhancement.
No further follow-up.
Malignant potential - nil

Bosniak 2:
Cystic or hyperdense, minimally complex, one or two thin ( less than 1mm, if more than 1 mm type 3) septations, thin calcification, no enhancement.
No further follow-up.
Malignant potential - nil

Bosniak 2F:
Cystic or hyperdense, minimally complex, well defined, round, thin (one or two) septations (less than 1mm), thick calcification, mild enhancement, less than 3cm diameter, at least 1/4 wall seen, solid component do not enhance.
Follow-up by US/CT.
Malignant potential is about 5%

Bosniak 3:
Indeterminate, thick or multiple septations, mural nodule, hyperdense on CT, shows enhancement, thick or irregular wall.
Need partial nephrectomy or RF ablation.
Malignant potential about 50%

Bosniak 4:
Clearly malignant, solid mass with cystic spaces, enhance.
Need partial / total nephrectomy.
Malignant rate nears 100%

Renal trauma: Grading

2009-12-09T16:10:00.000Z

AAST renal scale:

Grade1:
Non-expanding subcapsular haematoma with no laceration

Grade 2:
Non-expanding perinephric hameatoma confined to retroperitoneum
Lacerations less than 1 cm without involvement of pelvicalyceal system

Grade 3:
Laceration more than 1 cm without involvement of pelvicalyceal system

Grade 4:
Laceration extending through cortex, medulla and collecting system
Injury to main renal artery or vein with contained haematoma and/or segmental infarcts, but without lacerations

Grade 5:
Shattered kidney
Ureteopelvic avulsion
Complete avulsion or thrombosis of main renal artery or vein with complete devascularization

Endometrial carcinoma: Staging

2009-12-03T16:38:00.002Z

TNM/ FIGO staging of endometrial cancer:
I - T1: confined to corpus. IA-T1a - endometrium. IB-T1b - less than 1/2 of myometrium. Stage IC - T1C - more than 1/2 myometrium
II - T2: cervical extension. IIA-T2a - endocervical glandular. IIB-T2b - cervical stroma
III - T3: local +/- regional spread. IIIA-T3a - serosa/adnexa/peritoneal cytology. IIIB-T3b - vagina. IIIC-regional LN.
IVA - T4: mucosa of bladder/bowel involvement. IVB - Distant metastasis
Lymphnode drainage:
Mid and lower to parametrium, paracervical and obturator nodes - inguinal
Upper and fundus to iliac and para-aortic.

Intraventricular lesions

2009-12-03T16:37:00.001Z

Choroid plexus papilloma: rough-irregular surface, atriaof the lateral ventricles, children less than 10 years, homogenous marked enhancement

Meningioma: calcification common, trigone of lateral ventricle, not close to septum pellucidum, strong enhancement, older women

Astrocytoma: calcium +/-, peritumoral edema

Ependymoma: fourth ventricle, peritumoral brain invasion, childhood

Subependymoma: fifth decade, no enhancement

Central neurocytoma: 2-3 decade, lateral ventrcle with 3rd ventricle extension, attaches to septum pellucium, some enhencement, no peritumoral edema or brain invasion, calcium common

Gaint cell astrocytoma: in tuberous sclerosis, at lateral-third ventricle junction

Oligodendroglioma: rare, calcium, brain invasion,

Reference: Zhang et al. Central neurocytoma: clinical, pathological and neuroradiological findings. Clin Rad (2006): 61: 348-357
.

Lytic bone lesion

2009-12-03T16:31:00.000Z

Lytic lesion, location
Well defined - Narrow zone of transition = benign
Diaphyseal Medulla With or without sclerotic margin
Enchondroma - Hands and feet, May have GG appearance, May have calcification, mildly expansile, endosteal scalloping
EG - Can have sclerotic margin during healing, Sclerotic margin
SBC -
FD

- No sclerotic margin
Mets, plasmacytoma, lymphoma
Illdefined – wide zone of transition = malignant
Mets – may have narrow zone of transition
Myeloma – rain drops, multiple
Lymphoma
OS – periosteal reaction, osteoid matrix
Ewings – periosteal reaction, age
CS – cartilage matrix
MFH – non specific
Osteomyelitis – sequestraion, involucrum

Metaphyseal
ABC
Unfused epiphysis, expansile
NOF
Eccentric, medullary
FCD
Eccentric, cortical
CMF
May extend into epiphysis
May have sclerotic margins

Metaepiphyseal
GCT
Eccentric, expansile

Epiphpyseal
Brodie’s
CB
Epiphyseal
Can have calcification
Subarticular
OA/ CPPD/ arthritidis subarticular cysts
Gout
PVNS
Hemophilia
Mets, myeloma, lymphoma
GCT
CB
Post traumatic
TB

Grossly expansile

Mets
RCC
Thyroid
Melanoma
Also bronchus, breast, pheochromocytoma
Myeloma/ plasmacytoma
Lymphoma

CS
OS – telangiectactic

ABC
GCT
Enchondroma
FD

Hemophilic pseudotumor
Brown tumor

Calcium containing lytic lesions

Cartilage tumors
EC
CB
CMF
Bone tumors
OO
OB
OS
FD
Paget’s
OM sequestration
Introsseous lipoma

Moth eaten appearance

Mets
Myeloma
Lymphoma
Leukemia
Ewings
OS
CS
His X

Approach to joint disease

2009-12-03T16:30:00.000Z

SOFT TISSUE:

Soft tissue swelling/ nodules:
Gout - lobulated swelling, tophi
RA - earliest sign, very subjective,
PVNS - increased density
Sarcoidosis - rare
Amyloidosis - rare

Soft tissue calcification:
Scleroderma - tip of the fingers
Dermatomyositis - sheets ofdermal calcification

---------------------------------------------------------------------------------------

JOINT SPACE:

Preserved joint space till late:
Early pyogenic – may be wide
Psoriasis
Gout
PVNS
SLE

Increased joint space:
Acromegaly
Septic arthritis - early

Reduced joint space:
RA
Seronegative - late

---------------------------------------------------------------------------------------

EROSIONS:

Extra articular erosions:
Gout
Amyloid

Periarticular erosions = synovial:
RA
SS
SLE
AS
Reiter’s
Psoriatic
Enteropathic
JRA

Subchondral cysts/ erosions:
OA
Neuropathic
Hemophilia
CPPD
Hemochormatosis

---------------------------------------------------------------------------------------

Osteoporosis:
RA, JRA
SS
SLE
Pyogenic arthirtis, TB arthritis
Hemophilia

No osteoporosis:
OA
CPPD
Gout
Psoriasis
AS
Reiter’s
Neuropathic arthorpathy
PVNS

---------------------------------------------------------------------------------------

Perosteal reaction:
JRA
Reiter’s
Pyogenic arthirtis
AS
Psoriatic
Enteopathic
Hemophila
HOA (Pulmonary osteoarthropathy)

---------------------------------------------------------------------------------------

SCLEROSIS:

Subchondral sclerosis:
CPPD
OA
Neuropathic
Loose bodies

Cartilage calcification:
Osteophyte
OA
AS
Psoriasis

New bone formation:
Psoriasis
AS

---------------------------------------------------------------------------------------

Mono/ polyarticular
Septic arthritis
TB
Hemophilia
PVNS
RA
Symmetrical
RA
Asymmetrical
All including RA
Site
1st CMCJ
OA
RA
Radiocarpal
RA
OA
Intercarpal
JCA
RA
Metacarpophalyngeal
RA
Hemochromatosis
PIPJ
RA
DIPJ
Psoriasis
Erosive arthritis
Metatarsophalyngeal joint
RA
Gout
Interphalyngeal jonts
RA
OA
Psoriasis
Acroosteolysis
Psoriasis

History

Arthritis mutilans
RA
JRA
Psoriasis
Leprosy
Neuropathic joint
Reiter’s

Tunica Vaginalis pathology

2009-12-03T16:23:00.001Z

Congenital:
Patent processus vaginalais:
Spermatic cord hydrocele: Funicular hydrocele, encysted hydrocele
Inguinoscrotal hernia

Infection:
Scrotal abscess, pyocele
Scrotal tuberculosis
Scrotal scistosomiasis

Inflammation:
Acquired hydrocele
Scrotal pearls/ calculi
Fibrous pseudotumour of scrotum: nodular and diffuse types

Trauma:
Haematocele
Scrotal calculi
Fibrous pseudotumour
Scrotal tunical cyst

Tumour:
Adenomatoid tumour
Scrotal tunica cyst
Mesothelioma
Lipoma
Leiomyoma
Liposarcoma

Reference:
http://radiographics.rsna.org/content/29/7/2017.abstract
Leimyosarcoma

Absent nasal septum

2009-07-31T14:04:00.002+01:00

Cocaine
Wegener's granulomatosis
Surgery
Trauma
Syphillis
Sarcoidosis

Retroperitoneal lesions

2009-02-27T03:18:00.004Z

Fat containing:
Pelvic lipomatosis
Lipoma
Lipoblastoma (paediatric)
Liposarcoma
Hibernoma
Teratoma
Myelolipoma
Angiomyolipoma

Reference:
Craih WD et al. Fat-containing Lesions of the Retroperitoneum: Radiologic-Pathologic Correlation. RadioGraphics 2009;29:261-290. link: http://radiographics.rsnajnls.org/cgi/content/abstract/29/1/261

Tracheobraonchial tumours

2009-02-26T16:56:00.003Z

Malignant:
SCC, adenoid cystic carcinoma, adenocarcinoma, neuroendocrinal (carcinoid), sarcoma, lymphoma

Invasion:
from thyroid, larynx, lung or oesophageal carcinoma

Metastasis:
melanoma, breast, renal cell carcinom, colonic carcinoma

Benign:
papillomatosis, mesenchymal, mucus gland, salivary gland, neurogenic tumors

Reference:
Park CM et al. Tumors in the Tracheobronchial Tree: CT and FDG PET Features. RadioGraphics 2009;29:55-71. Link: RadioGraphics 2009;29:55-71

Differentiating acute and chronic pulmonary embolism

2009-02-26T13:41:00.004Z

Acute PE: diameter of pulmonary artery may be increased
Chronic PE: diameter of pulmonary artery may be decreased

Acute PE: may be central or eccentric; if eccentric, the filling defect shows acute angle with vessel wall; if central, defect may be surrounded by contrast
Chronic PE: peripheral crescent defect making obtuse angles with vessel wall

Acute PE atteniuation value (about 30 HU) is less than chronic PE (about 85 HU); this may be due to thrombus enhancement, iron and calcium.

Additional signs in acute PE: dilated right ventricle, deviation of interventricular septum towards left ventricle (right ventricular strain)

Additional signs in chronic PE: dilated bronchial arteries, dilated intercostal arteries, right ventricular hypertrophy.

Reference:
http://radiographics.rsnajnls.org/cgi/content/abstract/29/1/31
Castañer et al. CT Diagnosis of Chronic Pulmonary Thromboembolism. RadioGraphics 2009;29:31-50

Renal sinus

2009-02-10T15:07:00.003Z

Sinus fat: Renal sinus lipomatosis, Replacement lipomatosis
Renal sinus cyst: Peripelvic cyst (often bilateral, multiple, small, confluent, non-interconnected cysts), Parapelvic cyst (usually single, large, mostly from adjacent parenchyma), Parapelvic lymphatic cyst, parapelvic lymphangiectasia
Vascular: renal artery aneurysm, AVM, AVF, renal varices
Inflammation: spread of infection, especially fungal
Benign: leiomyoma, hemangioma, hemangiopericytoma
Malignant: TCC, SCC, leiomyosarcoma, metastasis, lymphoma
Others: Urinoma, Haematoma, multilocular cystic nephroma

Reference:
http://radiographics.rsnajnls.org/cgi/content/full/24/suppl_1/S117

Leptomeningeal thickening

2008-12-29T12:16:00.004Z

Leptomeningeal thickening may or may not enhance. Leptomengeal thickening secondary to , inflammation, tumour usually enhance. Leptomeningeal thickening secondary to SAH or craniotomy may not enhance. I have not included dural tail sign here.

Inflammation:
Histiocytosis X: paediatric
Sarcoidosis
Wegener's granulomatosis

Infection:
Meningitis - bacterial, TB, fungal, syphillis

Tumor:
Primary leptomeningeal glioblastomatosis
Primary leptomeningeal gliosarcomatosis
Sarcoma
Medulloblastoma - paediatric
Germinoma - paediatric
Pineoblastoma
Rupture of epidermoid - chemical meningitis
Meningeal carcinomatosis - breast, leukemia, lymphoma. lung, melanoma, GI, GU

Haemorrhage:
Old SAH

Post-Op:
Craniotomy scarring
Post LP

Mandibular lesions

2008-07-29T10:52:00.004+01:00

Cystic lesions
radicular cyst = periapical cyst - commonest - around the apex
dentigenorus cyst = follicular cyst - very common - around unerupted tooth
odontogenic keratocyst - body or ramus of mandible, expand/erode cortex
Stafne's cyst = static bone cavity - medial surface of the posterior mandible, filled with salivary gland. not true cyst
residual cyst - post op
premordial cyst - cyst in place of tooth
medullary pseuso cyst
SBC, ABC - like in other bones

Osseous lesions:
Odontogenic:
Benign:
odontoma - most common, between teeth, may be a/w impacted tooth, simple or compund
amelablastoma - posterior mandible - 3rd molar, soap bubble, +/- cortical erosion,
odontogenic myxoma, cementoblastoma, etc
Malignant: odontogenic carcinoma, odontogenic sarcoma, etc
Non-odontogenic:
Benign: ossigying fibroma, cemento-osseous dysplasias, exostosis - torus mandibularis, osteoma, FD, Pagets
Malignant: OS, CS, mets, lymphoma, leukemia, myeloma/plasmacytoma (rare), SCC

Soft tissue lesions:
Benign: NF, schwannoma, AVM, gaint cell reparative cyst, hemangioma,

Metabolic diseases:
osteoporosis, osteomalacia, renal osteodystrophy, osteitis fibrosa cystica

References:
Dunfee BL et al. Radiologic and Pathologic Characteristics of Benign and Malignant Lesions of the Mandible. RadioGraphics 2006;26:1751-1768

Multiple spine lesions

2008-07-24T10:33:00.002+01:00

Mets, myeloma, lymphoma
Hemagiomas, Multiple bone islands
Eosinophilic granulloma - young ones
Multifocal infection

Perirenal spaces

2008-07-20T00:37:00.003+01:00

Lymphoma, leukemia, mets
Extramedullary hemopoisis
Castleman's disease
Extraadrenal myelolipoma
Extension from renal lesion
Extension from retroperitoneal lesion

Reference:
Surabhi VR et al. Neoplastic and Non-neoplastic Proliferative Disorders of the Perirenal Space: Cross-sectional Imaging Findings. Radiographics 2008;28:1005-1017

Cystic pancreatic lesions

2007-12-20T16:43:00.001Z

Mucinous lesions (malignant or potentially malignant):
Mucinous cystic neoplasms (MCN)
Indtraductal papillary mucinous neoplasm (IPMN)

Non-mucinous lesions:
Serous cystadenoma
Pseudocyst
Epithelial cyst (in ADPKD, VHL syndrome, cystic fibrosis)

Scrotal lesions

2007-09-12T01:36:00.002+01:00

Testis:
Solid
Orchitis - large, hypervascular, a/w epididymitis
Infarct - wedge shaped, hypoechoic
Germ cell tumor - seminoma, non-seminomatous tumors
Epidermoid cyst - onion peel is diagnostic
Leydig cell hyperplasia - multiple small hypoechoic areas
Sarcoidosis - hypoechoic
Hematoma - hyper-iso-hypoechoic
Lymphoma
Metastasis
Cyst
Tunica albuginia cyct - periphery, small
Testicular cyst
Dilated rete testis
Calcium:
Microcalcifications
Regressing germ cell tumor

Epididymis:
Solid
Epididymitis - large, heterogenous and hypervascular
Adenomatoid tumor - most common epididymal tumor, common in lower pole,
Cystadenoma - a/w VHL disease

Spermatic cord:
Lipoma - most common spermatic cord tumor

Scrotal sac:
Scrotal pearls - fibrous pseudo tumors
Hidradenitis Suppurativa

Sclerotic bone lesions

2007-09-11T00:53:00.001+01:00

Generalized sclerosis
Mets - patchy, but can be diffuse in spine. Prostate in males, Breast in females
Paget’s – never forget, a/w bone expansion and thick trabeculae
Renal osteodystrophy – mixed, a/w brown tumors, subperiosteal resorption
Fluorosis - rare, but exam case; Thick cortex at expense of medulla, Periosteal reaction, Prominent tendon attachments, Changes most marked in pelvis and lumbar spine
Myelosclerosis - Patchy lucencies, look for clue - Hepatosplenomegaly
Mastocytosis - rare
Lymphoma - always keep in differential

Multiple sclerotic bones
Mets
FD – McCune Albright’s
Paget’s
Lymphoma
Melorheostosis - Molten wax flowing down the burning candle, sclerotome distribution, May have periosteal new bone formation
Mastocytosis

Multiple sclerotic lesions
Osteopoikilosis - periarticular, innocent lesions, no treatment required
Gardner’s - multiple osteomas
Infarcts - seprginous sclerotic areas, think of sickle cell
Callus - multiple fractures, think of OI
TS

Solitary sclerotic lesion
Mets - rarely solitory
Lymphoma
OO - cortical location with lucent nidus
OB - similar to OO, but larger
OS - agressive peristeal reaction and new bone formation
Osteoma - innocent
Bone island - innocent
FD - ground glass opacity
Bone infarct - serpigenous
Callus, healing fracture - compare with old films
Sclerosing OM of Garre
Paget’s - bone expansion, thick coarse trabeculae
Bone graft - well defined dense bone
Melorheostosis - Molten wax flowing down the burning candle, sclerotome, May have periosteal new bone formation

Solitary sclerotic lesion with lucent centre
OO
OB
Brodie’s abscess
TB

Sclerotic lesion with periosteal reaction
Healing fracture with callus
Mets
Lymphoma
OO
OB
OS
CS
Melorheostosis

PAEDIATRIC SCLEROSIS:
Generalized increase in bone density
< 1 year/ newborn Osteopetrosis - bone in bone
Pyknodysostosis -Hypoplastic lateral end of clavicle
Caffey’s infantle cortical hyperostosis - most common – clavicle, mandible, ribs; Massive periosteal bone formation, periosteal reaction; seen up to 6 months of age
Physiological
Idiopathic hypercalcemia of infancy
> 1year
Osteopetrosis
Pyknodysostosis
Renal osteodystrophy
Rickets
Hypervitaminosis A - not before 1 year, Cortical thickening, especially of feet, Subperiosteal new bone formation, Normal epiphysis
Hypervitaminosis D - Dense metaphyseal bands, Wide zone of provisional calcification
Focal sclerosis
Callus

Approach to joint diseases (arhtritides)

2007-09-11T00:39:00.001+01:00

The most important differentiation in any arthritides is between erosive and non-erosive arthritis. The following is extensive list of differentials, if combined together will help in reducing differentials.

Soft tissue swelling/ nodules
Gout
RA
PVNS
Sarcoidosis
Amyloidosis

Soft tissue calcification
Scleroderma
Dermatomyositis

Joint space
Preserved
Early pyogenic – may be wide
Psoriasis
Gout
PVNS
SLE
Increased
Acromegaly
Reduced
RA
Seronegative - late

Erosions
Extra articular
Gout
Amyloid
Periarticular = synovial
RA
SS
SLE
AS
Reiter’s
Psoriatic
Enteropathic
JRA
Subchondral
OA
Neuropathic
Hemophilia
CPPD
Hemochormatosis
Porosis
RA, JRA
SS
SLE
Pyogenic arthirtis, TB arthritis
Hemophilia

Osteoporosis
No porosis
OA
CPPD
Gout
Psoriasis
AS
Reiter’s
Neuropathic arthorpathy
PVNS
Porosis
RA
JRA

Perosteal reaction
JRA
Reiter’s
Pyogenic arthirtis
AS
Psoriatic
Enteopathic
Hemophila
HOA (Pulmonary osteoarthropathy)

Sclerosis
CPPD
OA
Neuropathic

Osteophytes
OA
AS
Psoriasis

New bone formation
Psoriasis
AS

Symmetry:
Symmetrical
RA
Asymmetrical
All including RA

Site
1st CMCJ
OA
RA
Radiocarpal
RA
OA
Intercarpal
JCA
RA
Metacarpophalyngeal
RA
Hemochromatosis
PIPJ
RA
DIPJ
Psoriasis
Erosive arthritis
Metatarsophalyngeal joint
RA
Gout
Interphalyngeal jonts
RA
OA
Psoriasis
Acroosteolysis
Psoriasis

Arthritis mutilans
RA
JRA
Psoriasis
Leprosy
Neuropathic joint
Reiter’s

Approach to bone tumours

2007-08-16T00:00:00.001+01:00

Is the tumour diaphyseal, metaphyseal or epiphyseal?

Diaphyseal
Lymphoma, Myeloma, mets - these DDs are always there
Ewing’s - young, onion peel periosteal reaction
Central chondrosarcoma - chondroid matrix, adult
OO - sclerotic, cortical
Diaphyseal OS - codman's triangle, periosteal reaction, osteoid formation
EC - hands and feet, meduallry, enosteal scalloping, cartilage matrix
SBC - lucent, no cartilage matrix, fallen fragment sign if fractured
FD - this DD is always there

Diametaphyseal
FCD, NOF - need no further follow up
FD - this DD is always there
CMF - rare, cartilage matrix
OO - cortical, sclerosis
SBC - lucent, no cartilage matrix, fallen fragment sign if fractured

Metaphyseal
Peripheral CS - chondroid matrix, adult
OS - codman's triangle, periosteal reaction, osteoid formation
SBC - lucent, no cartilage matrix, fallen fragment sign if fractured
OB - similar to OO, but larger, rare
EC - hands and feet, meduallry, enosteal scalloping, cartilage matrix
ABC - multicystic lucent, seen in unfused epiphysis (teens)

Metaepiphyseal = subarticular
GCT - soap bubble, after epiphyseal fusion, eccentric
CB - cartilage matrix

Epiphyseal
CB - Purely epiphyseal lesion, there is only one DD!

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Is the tumour medullary or cortical?

Medulla
Enchondroma - expansile, endosteal scalloping, cartilage matrix

Cortex
FCD - purely cortical

Both cortex and medulla
All others

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What is the age?

Baby
NB - neuroblastoma secondaries should always be considered
NAI - though not a tumour, may mimic
LCH - always bes considered

Child
Leukemia - more than one bone, medullary
Ewings - onion peel periosteal reaction

Teen
OS - Codman's triangle, osteoid matrix
ABC - before fusion of epiphysis, multiloculated

Adult
Rest of the primaries

Elderly
Mets
Myeloma
Lymphoma
Osteosarcoma in known Paget's

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Approach to bone radiography

2007-08-15T23:50:00.001+01:00

When you look at any extremity radiograph, the first question to be asked is...

Is it bone disease, joint disease or soft tissue disease?

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Remember to keep the following as differentials in all bone lesions:
Pagets
FD
Mets, myeloma, lymphoma
Trauma related

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Is it a single bone disease or more than one bone involved?
Single bone = Local disease
More than one bone = Systemic disease

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Is it a joint disease?

Is it monoarthirtis/ poly?
Bilateral/ unilateral?
Symmetric/ asymmtric?
Erosive or not?
Porotic or not?
Joint space narrowing or not?

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Is it a soft tissue disease?

Needs further imaging

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Cardiophrenic space

2007-08-14T22:35:00.001+01:00

Fat containing:
Normal or increased pericardial fat: obesity, steroids
Diaphragmatic hernia - Morgagni's, continues into abdomen
Pericardial fat necrosis - fat with stranding, rarely diagnosed on CT
Thymolipoma - continues to anterior mediastinum
Lipoma - rare
Liposarcoma - rare too

Cystic:
Pleuropericardial cyst - most common cystic lesion in cariophrenic recess, more common on right
Encysted pleural effusion
Thymic cyst - continues to anterior mediastinum
Hydatid cyst - tropical, daughter cysts

Solid:
Lymphnodes - lymphoma, metastasis, infection, inflammation
Thymoma - continues to anterior mediastinum

Air containing:
Diaphragmatic hernia - Morgagni's
Colonic interposition - rare

Vascular:
Varices - signs of cirrhosis of the liver

References:
Pineda V et al. Lesions of the Cardiophrenic Space: Findings at Cross-sectional Imaging. RadioGraphics 2007;27:19-32