Investigation of Choice

CT scan HRCT (basic principle: “Bone algorithm”+ 1mm sections + small FOV & Narrowbeam collumation).
Lungs: - ILD
- Bronchiectasis
- Emphysema

Temporal bone: - Petrositis
- Mastoiditis
- Ossicular chain disruption
- Cong. anom [e.g.Mondani’s malforman]..MRI can be equally good
- EAC osteoma
- Cholesteatoma
- Fracture facial canal

NonContrast CT (NCCT)
- Initial test of choice for acute stroke (to R/o hemorrhagic stroke)
- Fractures: Skull
Facial bones
Vertebral
Pelvis
Talus
Scaphoid
- Acute hemorrhage
Intratumoral
Intracerebral
Intraventriclular
EDH/SDH
Acute SAH
- Minimum air:
Pneumoperitonium
Pneumocephalus
Pneumomediastinum
- Calcification anywhere in body
- Ureteric calculi
- Head injury (both for fracture skull& for acute h’ges)
- Metallic foreign body especially in eye
- CT PNS (coronal CT)
- Chronic recurrent sinusitis
- Sinonasal polyps
- Complicated sinusitis
- Pre-FESS ct

CTA (CT angiography)
- Screening of intracranial internal carotid (ICA) lesions
- Screening of circle of Willi’s lesions
- Chronic abdominal angina (SMV thrombosis)
- Pulmonary embolism
- Non-invasive coronary angiography
- Coronary anomalies
- Pulmonary sequestration (angio will demonstrate the supplying artery which arises directly for descending thoracic aorta; most common in LLL)
- Rapid screening tool for aortic lesions (as is TEE)
- Sensitive and specific screening tool for Renal artery stenosis

CT Head
- Oligodendroglioma (dense, blotchy, nodular or ribbon-like calcification)
- Screening for cortical venous thrombosis (‘Empty delta sign’ inn lateral sinus thrombosis)
- Evaluation of an acute change in mental status
- Evaluation of an Focal neurologic findings
- Conductive hearing loss
- Craniopharyngioma (suprasellar arc-like/ring-like calcification)
- Craniosynostosis
- Krabbe’s disease (Globoid cell dystrophy): bilateral hypodense thalami

CECT neck
- Staging of Ca larynx
- Staging of Ca thyroid
- Nodal characterization

CT PNS
- Chronic/ recurrent sinusitis (NCCT)
- Noninvasive fungal sinusitis (NCCT)
- Sinonasal polyps (NCCT)
- Pre-FESS CT (NCCT)
- Neoplasms of maxilla (CECT)
- Juvenile angiofibroma (CECT; Holman Miller/Antral sign)
- Screening for Glomus jugulare (Phelp sign)
- CSF rhinorrhea (CT cisterography)

CT Orbit
- Metallic foreign body (NCCT)
- Optic drusen
- Retinoblastoma (calcification is pathognomonic; CECT)

CECT chest
- Screening, detection, and staging of lung cancer.
- Lung Hamartoma (well-defined mass with irregular or popcorn calcification)
- Pleural lesions
- Diaphragmatic hernia
- Anterior and middle mediastinal lesions.
- Congenital lobar emphysema (most common in LUL)
- Congenital adenomatoid lung malformation
- Morgagni’s hernia (seen at cardiophrenic angle)
- Medistinal lymphnode characterization (‘rim enhancement’=TB)
- Tubercular pericarditis
- Calcified cardiac tumors

CECT abdomen
- Blunt trauma abdomen (FAST i.e. Focused Assessment by Sonography for Trauma USG for screening & pref in hemodynamically unstable patients)
- Abdominal lump
- Abdominal wall hematoma
- Advanced rectal/ esophagus/ stomach/ bladder cancer
- Detection and Staging of Ca gall bladder and small bowel tumors
- Focal hepatic lesions
- Adrenal imaging (Nonfunctional lesions)
- Renal carcinoma detection and staging
- Oncocytoma (‘Central stellate’ scar)
- Renal and perirenal infections
- Complicated ADPKD
- Mesenteric cyst
- Enteric duplication cyst
- Abdominal lymphnode and peritoneal TB
- Diverticulitis and diverticular abscess (diverticulosis IOC=)
- Subdiaphragmatic abscess
- Bowel obstruction evaluation
- Complicated appendicitis
- Appendigitis epiploicae

CECT pelvis
- Adenexal mass
- Ovarian dermoid
- Ca urinary bladder
- Advanced prostatic cancer staging
- Sacrococcygeal teratoma

CRANIAL MRI
- Chronic Hemorrhage (GRE < FLAIR)
- Sensitive most for acute and hyperacute ischemic stroke (DWMRI)
- Demyelinating disorders (e.g. MS [Periventricular plaques; “Dawson’s fingers”], ALS, SSPE, SACD, SMON, CPM, ADEM, PML, PVL, PRES, etc)
- Infectious processes (encephalitis, meningitis)
- Abscesses
- Brain Neoplasms (supra as well as infra-tentorial & extra as well as intra-axial)
- Neurofibromatosis
- Diffuse Axonal Injury
- Vascular disorders (AVM’s, aneurysms, vasculitis, Moya-moya disease)
- Metastasis
- Internal auditory canal pathology
- Pituitary pathology
- Hydrocephalus especially in adults
- Cranial nerve pathology (e.g. vestibular schwannoma)
- Congenital anomalies (for anatomical review)
- Epilepsy (seizures in general)
- Parameningeal tumors
- Low CSF volume headache
Leptomeningeal metastases/carcinomatosis

SPINE MRI
- Cauda equina syndrome
- Tethered cord
- Arachnoiditis
- Marrow-replacing processes
- Degenerative disc disease
- Discitis
- Congenital anomalies
- Radiculopathy
- Spinal cord Tumours
- Trauma/contusion
- Syringomyelia
- Metastasis
- Vascular disorders
- Cord edema
- M.S. plaques
- Traumatic paraplegia
- Retroperitoneal tumor with spine extension
- Pott’s spine
- Myelomalacia

Musculoskeletal MRI
- Meniscal pathology
- Ligament/tendon injury
- PVNS
- Muscle/nerve impingement
- Rotator cuff tear
- Avascular necrosis
- Labral tears (shoulder, hip)
- Chondromalacia
- Inflammation (acute osteomyelitis)
- Primary bone tumors
- Spinal metastases
- Soft tissue tumors
- Perthe’s disease
- Cartilage injury (SPGRE sequence)

Cardiac MRI (Gating required):
- Infiltrative diseases like sarcoidosis, amyloidosis, etc
- Arrythmogenic Right Ventricular Dysplasia
- Ventricular function (accurate most)
- Myocardial perfusion especially in cases of Compact myocardium
- Post-op cases of Complex Congenital cyanotic heart disease
- Coarctation of aorta (better than 2D-echo because the size of stenosis, pre-stenotic lumen diameter and post-stenotic dilatated aortic size is best assessed; also echo has relatively poor acoustic window and is operator dependent).
- Cardiomyopathies (in general).
- Mediastinal masses Invading heart/pericardium
- Malignant cardiac tumors

MRCP:
- Congenital anomalies of bile duct and the entire biliary apparatus.
- Screening test of choice for primary sclerosing cholangitis, bile duct strictures, cholangiocarcinoma, bile leaks, etc
- Dysfunctional sphincter of oddi (scretin-MRCP).
- Liver donor transplant workup
- Segmental obstructions

MRA (Gd-enhanced MRA > TOF or PC MRA):
- Circle of Willis’s lesions
- Venous sinus thrombosis (MR venograms)
- Carotid and vertebral artery lesions
- Aortic lesions (in hemodynamically unstable patients we may prefer TEE or CT)
- Renal artery stenosis (3D-CE-Dynamic-MRA preferred)
- Vascular slings and anomalies (e.g. aberrant right subclavian, pulmonary sling, double aortic arch, right sided aortic arch, etc)

Miscellaneous:
- Retropharyngeal abscess
- Nasopharyngeal carcinoma
- Carotid lesions like carotid body tumor (Lyre’s sign-splaying of ECA from ICA)
- Posterior mediastinal lesions (because usually these are neurogenic)
- Superior sulcus tumor (Pancoast tumor)
- Staging of Ca prostate, ca endometrium and anorectal cancers
- Anorectal sepsis and malformations
- Sensitive most for extraadrenal pheochromocytoma (however sensitivity is less than that of DOPA-PET)
- Brachial plexus injuries (pre-ganglionic as well as post-ganglionic).
---------------------

Ultrasound - Hydrocephalus in infantsQ
- Thyroid nodule (hyperechoic lesions are less likely to be malignant)
- Initial evaluation of Rotator cuff injury/ subacromial bursitis/ bicipital tendinitisQ [MRI is more accurate and IOC]
- Synovial cysts (superficial ones)
- Pleural/ Pericardial effusionQ
- First investigation done for Acute abdomen and obstructive jaundice Q
- Congenital Hypertrophic Pyloric Stenosis (Target sign [transverse scan]; Cervix sign [longitudinal scan]).
- Intussusception (Doughnut sign [resolving one], Psuedokidney sign [basically consistent with bowel wall edema or thickening], Hamburger sign [longitudinal scan] and Target sign [transverse scan]).Q
- GallstonesQ
- Adenomyomatosis of Gall bladder (wall thickening of GB with “Comet tail” artefacts)
- Initial evaluation of focal liver lesions
- Initial evaluation of blunt trauma abdomen (FAST protocol) Q
- Minimal ascites Q
- Cystic hygroma
- Prostatic pathologies (TRUS)
- Seminal vesicle pathologies (TRUS)
- Staging of early rectal/pancreatic head malignancies (EUS)
- Neuroectodermal pancreatic tumors- insulinoma & gastrinoma (EUS)
- Scrotal pathologies
- Developmental dysplasia of HipQ
- Ectopic pregnancy (Empty uterus with pseudodecidual reaction with adnexal mass showing “Ring of fire” appearance on Doppler due to peritrophoblastic vascularity; TVS is IOC) Q