Role of imaging (images) in my practice Dr P Senthur Nambi Consultant Infectious Diseases
Medical images: My thoughts Images are just images Subject to the intellect of the interpreter View it in conjuction with history & clinical exam Disease evolves, so images evolve too Discuss with the radiologist
45 yrs male, fever with cough, sputum - 5 days Is it Bronchitis or Pneumonia?
Chest Xray in Pulmonary TB Reasonably sensitive but lacks specificity PPV around 60% & results in overtreatment May miss Mediastinal nodes Retrocardiac infiltrates Pulmonary vascular disease Miliary TB
X-ray based evaluation causes over diagnosis of TB 100 80 60 Overdiagnosis 40 20 0 Diagnosed by X- ray alone Actual cases NTI, Ind J Tuberc, 1974
THICK WALLED CAVITY IN LEFT MIDZONE..POOR RESPONSE TO ATT..
Fungal cultures..
Pneumonia with air bronchogram sign
Tree in bud appearance
Air fluid level
CT chest in FUO when? FUO with no localisation Patient has cough, SOB But normal chest x ray No sputum avl or unable to expectorate
Miliary TB
Necrotic mediastinal nodes Pericardial effusion
Lobar pneumonia Continues to have fever on appropriate therapy
20 years male, cough with dyspnoea - 1 month, 3kg weight loss
HRCT Thorax
CKD host on dialysis; cough with sputum 10 days
Unequivocal Halo sign surrounding a nodule Halo Small vessel angio invasion
Young male admitted with dengue..developed IV site phlebitis
US abdomen Liver or splenic enlargement or abscess Abdominal nodes Abdominal abscess Clarifies etiology of deranged LFT Renal abnormalities
USG Abdomen
Emphysematous cystitis Prostatic abscess
Loculated abscess collections (black arrows) posterior to the uterus (U)
Infected peritoneal fluid collection (A) with abnormal enhancement and thickening of the peritoneum (arrow).
Bilateral adrenal masses
CT abdomen When? Patient with pyelonephritis has fever on appropriate therapy FUO with no localisation & normal chest imaging Post intraabdominal surgery with complications
Meningitis Axial contrast-enhanced T1W MR image in a child with acute pyogenic meningitis reveals enhancing leptomeningeal exudates over bilateral cerebral convexities (arrows)
Meningitis - Acute complications Hydrocephalus Subdural effusion or empyema Stroke Abscess Dural sinus thrombophlebitis
Abscess Well defined Thick border Surrounding oedema
Etiology MRI Finding Herpes simplex Japanese B encephalitis West Nile virus Chandipura virus medial temporal lobe, cingulate gyrus, orbital surface of frontal lobes thalami (87-94%), substantia nigra, basal ganglia deep gray matter and brainstem (50%); white matter lesions mimicking demyelination; meningeal involvement on contrast enhanced images Normal EV 71 dorsal pons, medulla, midbrain, and dentate nuclei of the cerebellum; anterior horn cells of spinal cord in patients with acute flaccid paralysis
Herpes Encephalitis MR image shows high signal in the temporal lobes including hippocampal formations and parahippogampal gyrae, insulae, and right inferior frontal gyrus.
Chronic Meningoencephalitis (TB) Normal Enhancement in the basal cistern and meninges, with dilatation of the ventricles Tuberculous abscess in the left parietal region. Note the enhancing thick-walled abscess. 34
Tuberculoma Contrast MRI, showing multiple tuberculomas
Arachnoiditis Severe Arachnoiditis. A T2- weighted sagittal image reveals thickened nerve roots (arrows), intradural cysts (arrowheads) and pseudotethering
Poorly controlled diabetic..
PET CT Final frontier?
PET-CT scan Not a routine procedure in the workup of FUO due to high cost & limited availability Should eliminate the need for many unnecessary invasive & noninvasive diagnostic tests Important role as a second-line procedure in the management of nearly 50% of patients with FUO
Role of PET - CT Localisation of abnormal foci to guide the etiological diagnosis in FUO Diagnosis of infections in suspected chronic infections of bone & joints, painful hip prosthesis vascular prosthesis diabetes with suspicion of charcot s neuroarthropathy fever in AIDS
Role of PET-CT Detection of extent of inflammation in Sarcoidosis Inflammatory bowel disease Vasculitis involving the great vessels RA, Polymyalgia rheumatica Asses response to therapy
Imaging Final thoughts Important role in localising the site of problem & to analyse the extent of involvement Helps in predicting the etiology to some extent Great value in Immunecompromised host, HIV+ individuals Cost, commercial considerations Radiation exposure Special considerations (MRI, pregnancy)
Thanks..