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. 2021 Jun 1;9(4):283–297. doi: 10.1007/s40336-021-00435-y

Table 4.

Summary table on [18F]FDG PET/CT imaging in fungal and viral infections

Disease Clinical indication Patient preparation Imaging protocol Interpretation criteria Pitfalls Final report
Invasive Fungal Infections

To identify clinically occult and disseminated invasive fungal infections in immune-compromised and HIV-positive patients when CT is non-contributory;

To monitor treatment response;

To diagnose HIV-related opportunistic infections, associated neoplasms, and Castleman’s disease;

To monitor response to HAART in HIV-positive patients

To avoid the use of non-steroidal anti-inflammatory drugs, glucocorticoids or immunosuppressive agents;

According to EANM/SNMMI procedural guidelines

Whole body acquisitions (50–60’ after i.v. injection of 4–5 MBq/Kg of [18F]FDG);

Additional acquisition of lower limbs (1–3 min/bed) could be helpful in selected patients

Qualitative analysis

 (1) Pattern:

  Focal uptake: strongly suggestive for invasive fungal infections;

  Diffuse uptake in subcutaneous fat: could be related to HIV-associated lipodystrophy syndrome

 (2) Intensity of uptake:

  Splenic uptake > hepatic uptake: earlier stages of HIV with a lymphomatous involvement of the spleen;

  Hypermetabolism of basal ganglia and globally reduced cortical uptake: HIV patients with subclinical neurologic dysfunction;

  Increased uptake in bone marrow, spleen and lymph nodes: immune reconstitution inflammatory syndrome

Semi-qualitative analysis

 Limited role for SUVmax

FP findings in

 Neoplasms;

 Other infections;

 Benign hypermetabolic lymph nodes in HIV patients could mimic lymphoma

FN findings in:

 Small lesion size;

 Low metabolic rate;

 Ongoing steroid treatment

Presence/absence of lesions;

Pattern of uptake;

Location;

Extent;

Intensity of uptake;

Possible DD;

Comparison with previous [18F]FDG PET/CT if performed;

Time between injection and image acquisition (in order to better compare SUVmax of basal and FU studies)
SARS-CoV2

Detection of lung inflammatory status and evaluation of its extent;

Monitoring inflammation, its progression and treatment outcomes

According to

 EANM/SNMMI procedural guidelines

 Whole body acquisitions (60’ after i.v. injection of 2.5–5.0 MBq/Kg of [18F]FDG)

Qualitative analysis

 (1) Location

  Involved lung (right and/or left), lobes and segments, mediastinal lymph nodes

 (2) Pattern

  Usually diffuse uptake on ground-glass/consolidative area detected by CT

Semi-qualitative analysis

 Limited value for SUVmax

Drug-induced interstitial pneumonia;

Pneumonia of other etiology

Presence/absence of uptake;

Pattern of uptake;

Location;

Extent;

Intensity of uptake;

Evaluation of CT component;

Possible DD;

Comparison with previous [18F]FDG PET/CT if performed;

Comparison to previous 18F-FDG PET/CT, if performed;

Time between injection and image acquisition (in order to better compare SUVmax of basal and FU studies)

HIV human immunodeficiency virus, HAART highly active anti-retroviral therapy, EANM European Association of Nuclear Medicine, SNMMI Society of Nuclear Medicine and Molecular Imaging, i.v. intra-venous, MBq Mega Bequerel, Kg Kilograms, [18F]FDG 18Fluorine fluorodeoxyglucose, p.i. post-injection, SUVmax standardized uptake value, FP false positive, FN false negative, FU follow-up, DD differential diagnosis, SARS-CoV2 severe acute respiratory syndrome coronavirus 2, CT computed tomography, PET/CT positron emission tomography/computed tomography